objc2-file-provider 0.3.2

//! This file has been automatically generated by `objc2`'s `header-translator`.
//! DO NOT EDIT
use core::ffi::*;
use core::ptr::NonNull;
use objc2::__framework_prelude::*;
#[cfg(feature = "objc2-core-foundation")]
use objc2_core_foundation::*;
use objc2_foundation::*;

use crate::*;

/// Options passed on item creation.
///
/// See also [Apple's documentation](https://developer.apple.com/documentation/fileprovider/nsfileprovidercreateitemoptions?language=objc)
// NS_OPTIONS
#[repr(transparent)]
#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash, PartialOrd, Ord)]
pub struct NSFileProviderCreateItemOptions(pub NSUInteger);
bitflags::bitflags! {
    impl NSFileProviderCreateItemOptions: NSUInteger {
/// The imported item may already exist.
///
/// This can happen because:
///
/// 1. The imported item was found on disk after the synchronisation state was
/// lost, for example following the restoration of a backup, or the migration
/// to a new device.
///
/// 2. Two directories are merged together, due to the extension returning
/// the same itemIdentifier for both directories on the createItem completion handler.
/// Each child resulting of the merge may be recreated with the
/// mayAlreadyExist option. This allows the extension to recursively merge
/// directories.
///
/// The Extension should assess whether the item could actually be a disk
/// representation of an already existing item.
///
/// The best user experience is to match the requested item to one on the server,
/// if the extension is able to confirm that the disk item is representing an item already on
/// the server.
///
/// Given that this flag may be set when the system is reimporting all items from disk,
/// it is advised that the Extension attempts assessment methods for each item
/// in order from cheapest to most expensive (in terms of CPU and network), in order
/// to avoid unnecessary work.
///
/// When all the items pending reimport have been processed, the system
/// will call -[NSFileProviderExtension importDidFinishWithCompletionHandler:].
        #[doc(alias = "NSFileProviderCreateItemMayAlreadyExist")]
        const MayAlreadyExist = 1<<0;
/// This item is recreated after the system failed to apply a deletion requested
/// by the extension because the item was found to be edited locally.
/// This happens only if the edit wasn't yet known by the system at the time the
/// deletion was requested.
        #[doc(alias = "NSFileProviderCreateItemDeletionConflicted")]
        const DeletionConflicted = 1<<1;
    }
}

unsafe impl Encode for NSFileProviderCreateItemOptions {
    const ENCODING: Encoding = NSUInteger::ENCODING;
}

unsafe impl RefEncode for NSFileProviderCreateItemOptions {
    const ENCODING_REF: Encoding = Encoding::Pointer(&Self::ENCODING);
}

/// Options passed on item deletion.
///
/// See also [Apple's documentation](https://developer.apple.com/documentation/fileprovider/nsfileproviderdeleteitemoptions?language=objc)
// NS_OPTIONS
#[repr(transparent)]
#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash, PartialOrd, Ord)]
pub struct NSFileProviderDeleteItemOptions(pub NSUInteger);
bitflags::bitflags! {
    impl NSFileProviderDeleteItemOptions: NSUInteger {
/// The deletion of the item is recursive.
        #[doc(alias = "NSFileProviderDeleteItemRecursive")]
        const Recursive = 1<<0;
    }
}

unsafe impl Encode for NSFileProviderDeleteItemOptions {
    const ENCODING: Encoding = NSUInteger::ENCODING;
}

unsafe impl RefEncode for NSFileProviderDeleteItemOptions {
    const ENCODING_REF: Encoding = Encoding::Pointer(&Self::ENCODING);
}

/// NSFileProviderMaterializationFlags are used to inform the system about specific conditions
/// that apply to the content retrieved by the provider in fetchPartialContentsForItemWithIdentifier.
///
/// See also [Apple's documentation](https://developer.apple.com/documentation/fileprovider/nsfileprovidermaterializationflags?language=objc)
// NS_OPTIONS
#[repr(transparent)]
#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash, PartialOrd, Ord)]
pub struct NSFileProviderMaterializationFlags(pub NSUInteger);
bitflags::bitflags! {
    impl NSFileProviderMaterializationFlags: NSUInteger {
/// By default, the system will track which parts of the returned file are sparse; those parts will remain non-materialized
/// and trigger subsequent calls to the materialization methods on access. Returning this flag will instead cause the entire
/// file to be marked as materialized. This is useful if the resulting file is known to contain sparse parts,
/// and all the remaining parts have been filled in.
/// This flag is ignored if the provided range doesn't cover the entire file (ie. [0, EOF]).
/// This flag is not functional prior to macOS 13.3.
        #[doc(alias = "NSFileProviderMaterializationFlagsKnownSparseRanges")]
        const KnownSparseRanges = 1<<0;
    }
}

unsafe impl Encode for NSFileProviderMaterializationFlags {
    const ENCODING: Encoding = NSUInteger::ENCODING;
}

unsafe impl RefEncode for NSFileProviderMaterializationFlags {
    const ENCODING_REF: Encoding = Encoding::Pointer(&Self::ENCODING);
}

/// Used by the system to express options and constraints to the provider in fetchPartialContentsForItemWithIdentifier.
///
/// See also [Apple's documentation](https://developer.apple.com/documentation/fileprovider/nsfileproviderfetchcontentsoptions?language=objc)
// NS_OPTIONS
#[repr(transparent)]
#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash, PartialOrd, Ord)]
pub struct NSFileProviderFetchContentsOptions(pub NSUInteger);
bitflags::bitflags! {
    impl NSFileProviderFetchContentsOptions: NSUInteger {
/// Set by the system to inform the provider that any other content version than the requested one
/// will be discarded.
/// If the provider cannot supply this version, it should fail with NSFileProviderErrorVersionNoLongerAvailable.
        #[doc(alias = "NSFileProviderFetchContentsOptionsStrictVersioning")]
        const StrictVersioning = 1<<0;
    }
}

unsafe impl Encode for NSFileProviderFetchContentsOptions {
    const ENCODING: Encoding = NSUInteger::ENCODING;
}

unsafe impl RefEncode for NSFileProviderFetchContentsOptions {
    const ENCODING_REF: Encoding = Encoding::Pointer(&Self::ENCODING);
}

extern_protocol!(
    /// [Apple's documentation](https://developer.apple.com/documentation/fileprovider/nsfileproviderenumerating?language=objc)
    pub unsafe trait NSFileProviderEnumerating: NSObjectProtocol {
        #[cfg(all(
            feature = "NSFileProviderEnumerating",
            feature = "NSFileProviderItem",
            feature = "NSFileProviderRequest"
        ))]
        /// Create an enumerator for an item.
        ///
        /// This method is called when the user lists the content of folder it never accessed
        /// before. This can happen either when using Finder or when listing the content of
        /// the directory from a Terminal (for instance using the `ls` command line tool). The
        /// system will use the enumerator to list the children of the directory by calling
        /// -[NSFileProviderEnumerator enumerateItemsForObserver:startingAtPage:] until nil
        /// is passed to -[NSFileProviderEnumerationObserver finishEnumeratingUpToPage:].
        /// Once this has been called, the directory and its children should be included in the
        /// working set.
        ///
        /// This is also used to subscribe to live updates for a single document.
        ///
        /// The system will keep an enumerator open in the extension on directories that are
        /// presented to the user (for instance, in Finder), and on document on which an application
        /// has a NSFilePresenter. The provider can use the existence of that enumerator as a hint
        /// that the user is actively seeing / using the item in question, and prioritize the delivery
        /// of updates on the item or its children in the working set.
        ///
        /// If returning nil, you must set the error out parameter.
        ///
        /// Working set enumerator:
        /// -----------------------
        /// The working set enumerator is a special enumerator (NSFileProviderWorkingSetContainerItemIdentifier)
        /// the system uses to detect changes that should be synced to the disk and/or searchable
        /// in Spotlight. Because that enumerator is by definition used for change detection, the
        /// working set enumerator must implement
        /// -[NSFileProviderEnumerator enumerateChangesForObserver:fromSyncAnchor:] and
        /// -[NSFileProviderEnumerator currentSyncAnchorWithCompletionHandler:].
        ///
        /// The system guarantees that it has a single consumer for the working set. This means there
        /// will never be two concurrent enumerations of the working set and will always do forward
        /// progress: the system will only ask for changes from the last requested sync anchor or
        /// the last returned sync anchor and the extension should be prepared for it.
        ///
        /// The expiration of the sync anchor of the working set will cause a very expensive scan
        /// of all the items known by the system.
        ///
        /// The system ingests the changes from the working set and applies the changes to the
        /// disk replicate and the spotlight index. Before ingesting the update for an item,
        /// the system will check if the enumeration of the item races against a call to
        /// createItemBasedOnTemplate, modifyItem, ... that may affect the item. If a potential race
        /// is detected, the system will call itemForItemIdentifier in order to resolve the race.
        ///
        /// If the provider exposes the key NSExtensionFileProviderAppliesChangesAtomically with value
        /// YES in its Info.plist, it is considered to apply the changes atomically, in which case the
        /// system does not need to check for potential races.
        ///
        /// Execution time:
        /// ---------------
        /// The system expects this call to complete quickly, it should build the object that will be
        /// used for enumeration and return it. The enumeration logic should happen when the system
        /// calls `-[NSFileProviderEnumerator enumerateItemsForObserver:startingAtPage:]` or
        /// `-[NSFileProviderEnumerator enumerateChangesForObserver:fromSyncAnchor:]`.
        ///
        /// Error cases:
        /// ------------
        /// If containerItemIdentifier is NSFileProviderTrashContainerItemIdentifier and
        /// the extension does not support trashing items, then it should fail the call
        /// with the NSFeatureUnsupportedError error code from the NSCocoaErrorDomain
        /// domain.
        ///
        /// If the item requested containerItemIdentifier does not exist in the provider,
        /// the extension should fail with NSFileProviderErrorNoSuchItem. In that case,
        /// the system will consider the item has been deleted and attempt to delete the
        /// item from disk.
        ///
        /// The extension can also report the NSFileProviderErrorNotAuthenticated,
        /// NSFileProviderErrorServerUnreachable in case the item cannot be fetched
        /// because of the current state of the system / domain. In that case, the
        /// system will present an appropriate error message and back off until the
        /// next time it is signalled.
        ///
        /// Any other error, including crashes of the extension process, will be considered to be transient
        /// and will cause the enumeration to be retried.
        ///
        /// Errors must be in one of the following domains: NSCocoaErrorDomain, NSFileProviderErrorDomain.
        ///
        /// For errors which can not be represented using an existing error code in one of these domains, the extension
        /// should construct an NSError with domain NSCocoaErrorDomain and code NSXPCConnectionReplyInvalid.
        /// The extension should set the NSUnderlyingErrorKey in the NSError's userInfo to the error which could not
        /// be represented.
        #[unsafe(method(enumeratorForContainerItemIdentifier:request:error:_))]
        #[unsafe(method_family = none)]
        unsafe fn enumeratorForContainerItemIdentifier_request_error(
            &self,
            container_item_identifier: &NSFileProviderItemIdentifier,
            request: &NSFileProviderRequest,
        ) -> Result<Retained<ProtocolObject<dyn NSFileProviderEnumerator>>, Retained<NSError>>;
    }
);

extern_protocol!(
    /// FileProvider extension for which the system replicates the content on disk.
    ///
    /// The extension exposes a hierarchy of NSFileProviderItem instances that the system
    /// will replicate on disk as a file hierarchy. The file hierarchy reflects the filename,
    /// parent, content, and metadata described by the NSFileProviderItem. In case two items
    /// are at the same disk location (same parent and filename), the system may choose to
    /// "bounce" an item.
    ///
    /// The system lazily replicates the item hierarchy: items are created "dataless" on disk
    /// and the content (for files) or list of children (for folders) is fetched on first
    /// access by calling fetchContentsForItemWithIdentifier, or enumeratorForContainerItemIdentifier.
    ///
    /// The provider can notify the system of changes on the items by publishing those on the
    /// enumerator for the working set. The system notifies the extension of changes made by the
    /// user on disk by calling createItemBasedOnTemplate, modifyItem, or deleteItemWithIdentifier.
    ///
    /// Concurrency:
    /// ------------
    /// A replicated extension class must be prepared to handle multiple concurrent calls since the
    /// system may perform several concurrent operations (for instance, modifying an item, while enumerating
    /// the working set, creating another item, and fetching the contents of yet another item).
    ///
    /// The system has limits to the number of concurrent operations.When the number of concurrent
    /// operations is reached, the system will not schedule additional operations falling in that category
    /// until at least one of the running operation has completed by calling its completion handler.
    ///
    /// The system currently separates the operations into the following categories:
    /// - enumeration of the working set. At most 1 enumeration of the working set can happen at a given time
    /// - downloads. The system has a per-domain limit on the number of concurrent calls to fetchContents and similar calls.
    /// That limit is configurable by setting the NSExtensionFileProviderDownloadPipelineDepth key to an integer
    /// value (between 1 and 128) in the Info.plist of the extension.
    /// The configuration key is honored starting in macOS 11.0 and iOS 16.0.
    /// - uploads. The system has a per-domain limit on the number of concurrent calls to createItemBasedOnTemplate and
    /// modifyItem when the call includes new content to be uploaded.
    /// That limit is configurable by setting the NSExtensionFileProviderUploadPipelineDepth key to an integer value
    /// (between 1 and 128) in the Info.plist of the extension.
    /// The configuration key is honored starting in macOS 12.0 and iOS 16.0.
    /// - metadata-only uploads. The system has a per-domain limit on the number of concurrent calls to createItemBasedOnTemplate
    /// and modifyItem when the call does not include new content to be uploaded.
    /// That limit is configurable by setting the NSExtensionFileProviderMetadataOnlyUploadPipelineDepth key to an
    /// integer value (between 1 and 128) in the Info.plist of the extension.
    /// The configuration key is honored starting in macOS 15.0 and iOS 18.0.
    ///
    /// See also [Apple's documentation](https://developer.apple.com/documentation/fileprovider/nsfileproviderreplicatedextension?language=objc)
    pub unsafe trait NSFileProviderReplicatedExtension:
        NSObjectProtocol + NSFileProviderEnumerating
    {
        #[cfg(feature = "NSFileProviderDomain")]
        /// Create a new instance of the replicated provider for the specified domain.
        #[unsafe(method(initWithDomain:))]
        #[unsafe(method_family = init)]
        unsafe fn initWithDomain(
            this: Allocated<Self>,
            domain: &NSFileProviderDomain,
        ) -> Retained<Self>;

        /// Called before the instance is discarded.
        ///
        /// Several instances of a replicated provider can be hosted by the same process, either because
        /// the user has several active domains, or because an instance got discarded and a new one
        /// is created by the system. This method is called before an instance is discarded and should
        /// make sure that all references to the instance are released so that the instance can be
        /// deallocated.
        #[unsafe(method(invalidate))]
        #[unsafe(method_family = none)]
        unsafe fn invalidate(&self);

        #[cfg(all(
            feature = "NSFileProviderItem",
            feature = "NSFileProviderRequest",
            feature = "block2"
        ))]
        /// Fetch the metadata for the item with the provider identifier.
        ///
        /// Error cases:
        /// ------------
        /// If the metadata lookup fails because the item is unknown, the call should
        /// fail with the NSFileProviderErrorNoSuchItem error. In that case, the system
        /// will consider the item has been removed from the domain and will attempt to
        /// delete it from disk. In case that deletion fails because there are local
        /// changes on this item, the system will re-create the item using createItemBasedOnTemplate.
        ///
        /// The extension can also report the NSFileProviderErrorNotAuthenticated,
        /// NSFileProviderErrorServerUnreachable in case the item cannot be fetched
        /// because of the current state of the system / domain. In that case, the
        /// system will present an appropriate error message and back off until the
        /// next time it is signalled.
        ///
        /// Any other error, including crashes of the extension process, will be considered to be
        /// transient and will cause the lookup to be retried.
        ///
        /// Errors must be in one of the following domains: NSCocoaErrorDomain, NSFileProviderErrorDomain.
        ///
        /// For errors which can not be represented using an existing error code in one of these domains, the extension
        /// should construct an NSError with domain NSCocoaErrorDomain and code NSXPCConnectionReplyInvalid.
        /// The extension should set the NSUnderlyingErrorKey in the NSError's userInfo to the error which could not
        /// be represented.
        ///
        /// Cancellations:
        /// ------------
        /// If the NSProgress returned by this method is cancelled, the extension should
        /// call the completion handler with (nil, NSUserCancelledError) in the NSProgress
        /// cancellation handler.
        ///
        /// Execution time:
        /// ---------------
        /// This method is not expected to take more than a few seconds to complete the retrieval of the
        /// metadata of the item. If the operation may not complete in a reasonable amount of time because,
        /// for instance, of bad network conditions, it is recommended to report an error (for instance
        /// NSFileProviderErrorServerUnreachable). The system will call `cancel` on the progress if the
        /// operation takes too much time. The extension is then expected to quickly call the completion
        /// handler.
        #[unsafe(method(itemForIdentifier:request:completionHandler:))]
        #[unsafe(method_family = none)]
        unsafe fn itemForIdentifier_request_completionHandler(
            &self,
            identifier: &NSFileProviderItemIdentifier,
            request: &NSFileProviderRequest,
            completion_handler: &block2::DynBlock<dyn Fn(*mut NSFileProviderItem, *mut NSError)>,
        ) -> Retained<NSProgress>;

        #[cfg(all(
            feature = "NSFileProviderItem",
            feature = "NSFileProviderRequest",
            feature = "block2"
        ))]
        /// Download the item for the given identifier and return it via the completion handler.
        ///
        /// The system learns of items through enumerations. Initially, this means that the
        /// system is aware that an item (with a specific version) exists on the device.
        ///
        /// When the user accesses the item, the system makes a request for the contents of
        /// the item. The provider can then fulfill the request by providing the item.
        ///
        /// The system takes ownership of the item and will move it out of the sandbox of
        /// the provider.
        ///
        /// If the provider wishes to force materialization of a given item, the provider should use
        /// `-[NSFileProviderManager requestDownloadForItemWithIdentifier:requestedRange:completionHandler:]`,
        /// or configure the `-[NSFileProviderItem contentPolicy]`.
        ///
        /// The requestedVersion parameter specifies which version should be returned. A nil value
        /// means that the latest known version should be returned. Except for the error case, the
        /// version of the returned item is assumed to be identical to what was requested.
        ///
        /// requestedVersion is currently always set to nil.
        ///
        /// Concurrent Downloads:
        /// ----------
        /// The system will call fetchContents concurrently if there are multiple outstanding file download requests.
        /// The provider can control the concurrency by setting the key NSExtensionFileProviderDownloadPipelineDepth
        /// in the Info.plist of the extension to the number of concurrent downloads that the system should create
        /// per domain. This number must be between 1 and 128, inclusive.
        ///
        /// File ownership:
        /// ---------------
        /// The retrieved content at `fileContents` URL must be a regular file on the same volume as the user-visible URL.
        /// A suitable location can be retrieved using -[NSFileProviderManager temporaryDirectoryURLWithError:].
        /// The system clones and unlinks the received fileContents. The extension should not mutate the corresponding
        /// file after calling the completion handler. If the extension wishes to keep a copy of the content, it must
        /// provide a clone of the that content as the URL passed to the completion handler.
        ///
        /// In case the extension or the system crashes between the moment the completion handler is called and the
        /// moment the system unlinks the file, the file may unexpectedly still be on disk the next time an instance
        /// of the extension is created. The extension is then responsible for deleting that file.
        ///
        /// Disallowing processes from fetching items:
        /// ---------------
        ///
        /// The system automatically downloads files on POSIX accesses. The extension may wish to disallow this class of
        /// downloads for specific applications.
        ///
        /// The extension can set an array of strings into the UserDefault key
        /// "NSFileProviderExtensionNonMaterializingProcessNames". A process whose executable's filename on disk is an
        /// exact match for an entry in this array will not be allowed to fetch items in the extension's domains. The comparison
        /// is case sensitive.
        ///
        /// In macOS 11.0 and later, this list will be checked when a download is initiated through a POSIX filesystem call.
        /// In macOS 11.4 and later, this list will also be checked for downloads initiated through file coordination.
        ///
        /// Error cases:
        /// ------------
        /// If the download fails because the item was deleted on the server, the call should
        /// fail with the NSFileProviderErrorNoSuchItem error. In that case, the system
        /// will consider the item has been removed from the domain and will attempt to
        /// delete it from disk. In case that deletion fails because there are local
        /// changes on this item, the system will re-create the item using createItemBasedOnTemplate,
        /// passing the NSFileProviderCreateItemDeletionConflicted flag.
        ///
        /// If the user does not have access to the content of the file, the provider
        /// can fail the call with NSCocoaErrorDomain and code NSFileReadNoPermissionError.
        /// That error will then be presented to the user. The extension can also report
        /// the NSFileProviderErrorNotAuthenticated, NSFileProviderErrorServerUnreachable
        /// in case the item cannot be fetched because of the current state of the system / domain.
        /// In those cases, the system will present an appropriate error message and back off
        /// until the next time it is signalled.
        ///
        /// Any other error, including crashes of the extension process, will be considered to be transient
        /// and will cause the download to be retried.
        ///
        /// Errors must be in one of the following domains: NSCocoaErrorDomain, NSFileProviderErrorDomain.
        ///
        /// For errors which can not be represented using an existing error code in one of these domains, the extension
        /// should construct an NSError with domain NSCocoaErrorDomain and code NSXPCConnectionReplyInvalid.
        /// The extension should set the NSUnderlyingErrorKey in the NSError's userInfo to the error which could not
        /// be represented.
        ///
        /// Cancellations:
        /// ------------
        /// If the NSProgress returned by this method is cancelled, the extension should
        /// call the completion handler with (nil, nil, NSUserCancelledError) in the NSProgress
        /// cancellation handler.
        ///
        /// The returned NSProgress is used to show progress to the user. If the user cancels the
        /// fetch, the extension should stop fetching the item, as it is no longer required.
        ///
        /// Execution time:
        /// ---------------
        /// The system will grant enough time to the extension to download the file. The system will interrupt the
        /// call if it stops making progress or if download takes an unexpectedly long time. In that case, the system
        /// will call `cancel` on the progress. The extension is then expected to quickly call the completion
        /// handler.
        #[unsafe(method(fetchContentsForItemWithIdentifier:version:request:completionHandler:))]
        #[unsafe(method_family = none)]
        unsafe fn fetchContentsForItemWithIdentifier_version_request_completionHandler(
            &self,
            item_identifier: &NSFileProviderItemIdentifier,
            requested_version: Option<&NSFileProviderItemVersion>,
            request: &NSFileProviderRequest,
            completion_handler: &block2::DynBlock<
                dyn Fn(*mut NSURL, *mut NSFileProviderItem, *mut NSError),
            >,
        ) -> Retained<NSProgress>;

        #[cfg(all(
            feature = "NSFileProviderItem",
            feature = "NSFileProviderRequest",
            feature = "block2"
        ))]
        /// Create a new item.
        ///
        /// The itemTemplate object describes the expected state of the newly created item,
        /// including its location provided by parentItemIdentifier and filename. The list
        /// of fields to conside in that object is defined by the fields parameter. Fields
        /// not listed should be considered as not being defined.
        ///
        /// The url is used to transfer the content of the file from the system to the
        /// extension. It can be nil if the item has no content. This will be the case if
        /// the item is a folder or if the item is being reimported (flag
        /// NSFileProviderCreateItemMayAlreadyExist set) and the file is dataless on disk.
        /// If the item is a symbolic link, the target path is provided by the symlinkTargetPath
        /// of the itemTemplate.
        ///
        /// The system is setting the itemIdentifier of the itemTemplate to a unique value that
        /// is guaranteed to stay the same for a given item in case the creation is replayed
        /// after a crash. That itemIdentifier is not intended to be the identifier assigned
        /// to the item by the provider.
        ///
        /// In the completion block, the createdItem is expected to reflect the properties of the
        /// newly created item, which usually means matching the properties passed in by the
        /// template. An exception is the itemIdentifier which should be the identifier assigned
        /// to that item by the provider rather than the identifier passed in through the template.
        /// If the provider reuses an existing identifier, the item that used that identifier will
        /// be removed from disk, replaced by the createdItem. If the item is a directory, the two
        /// directories will be merged and the items from the existing one will be modified with
        /// the NSFileProviderModifyItemMayAlreadyExist option set.
        ///
        /// If the provider is not able to apply all the fields at once, it should return a
        /// set of stillPendingFields in its completion handler. In that case, the system will
        /// attempt to modify the item later by calling modifyItem with those fields.
        ///
        /// The filename and contents fields should be synced together.
        /// If synced independently, files may appear corrupted on other devices, due to
        /// a mismatch between the file extension and the actual file data.
        ///
        /// If a field in the returned createdItem does not match the itemTemplate, and is
        /// not in the list of stillPendingFields, the value from the createdItem will be
        /// propagated to the disk. If the content of the item as described by createdItem
        /// does not match the content from url, the provider should set shouldFetchContent
        /// in the completion handler. The content from the provider will then be fetched
        /// and propagated to disk.
        ///
        /// In case the deletion of an item from the working set could not be applied to the
        /// disk by the system because it conflicted with a local edit of the file, the system
        /// will attempt to create the edited item. In that case the creation call will receive
        /// the NSFileProviderCreateItemDeletionConflicted option and the itemIdentifier in the
        /// template will be set to the itemIdentifier of the item deleted from the working set.
        /// The itemVersion will also be set to the last itemVersion of the item that was made
        /// available on disk before the item was edited locally. If such a conflict happens
        /// on a dataless item on disk, the item will be immediately deleted from the disk instead
        /// of issuing a new creation.
        ///
        /// In case the NSFileProviderCreateItemMayAlreadyExist option
        /// is passed, the content may be nil if the item is found by the system without any
        /// associated content. In that case, you should return a nil item if you are not
        /// able to match the created item with an existing item from the provider.
        ///
        /// In case of path collision with an already existing item, the provider
        /// can either fail using -[NSError (NSFileProviderError) fileProviderErrorForCollisionWithItem:]
        /// or resolve the collision by itself (e.g. by returning an item with a different name).
        /// If the error is returned, the system will try to resolve the collision by itself by bouncing
        /// away one of the items (renaming the item).
        ///
        /// If the imported item is refused by the extension, it should return nil for the
        /// createdItem without any error. In that case, the source item will be deleted
        /// from disk. In case the item represents a directory, the content will be deleted
        /// recursively.
        ///
        /// If the extension does not wish to sync the item, while still
        /// keeping the item on disk, on macOS 13.0, iOS 16.0, and later,
        /// it should return `NSFileProviderErrorExcludedFromSync`
        /// on the completion handler. For more details, see the header comment for that
        /// error code.
        /// On earlier versions of macOS, where `NSFileProviderErrorExcludedFromSync` is
        /// unavailable, the extension could choose to respond to FileProvider API calls as
        /// if the item is synced to it's server, but the extension only tracks the item
        /// in it's own local database on the device. The extension must be careful to respond to
        /// all FileProvider API calls as if the file is really synced to it's server, including
        /// enumerations of the parent directory of that item, itemForIdentifier calls, etc.
        ///
        /// The progress returned by createItemBasedOnTemplate is expected to include the
        /// upload progress of the item and will be presented in the user interface until
        /// the completion handler is called.
        ///
        /// Creation is gated by the NSFileProviderItemCapabilitiesAllowsAddingSubItems
        /// capability on the parent folder on a UI level, but direct file system changes
        /// (e.g. from Terminal) can still result in changes that must be handled.
        ///
        /// Structural consistency:
        /// -----------------------
        /// The system guarantees that the creation is called after the creation of the
        /// parent completed.
        ///
        /// File ownership:
        /// ---------------
        /// The file at `url` is owned by the system and is unlinked after the completion
        /// handler is called. If the extension wishes to keep access to the content of
        /// file after calling the completion handler, it should clone the file in its
        /// container.
        ///
        /// Atomicity:
        /// ----------
        /// By default, the system assumes all the changes are applied non-atomically, which
        /// means that the change or an intermediary state from the change can be observed
        /// (for instance while enumerating the working set) while the call is in progress
        /// (before the completion handler is called). The provider can indicate to the system
        /// that it applies changes atomically (that is, the change cannot be observed before
        /// the completion handler is called) by setting the key NSExtensionFileProviderAppliesChangesAtomically
        /// in the Info.plist of the extension to YES.
        ///
        /// The atomicity declaration only describes the visibility of the changes, not
        /// the ability of the provider to apply all the fields at once: a provider that applies
        /// changes atomically might still apply a subset of the changedFields communicated
        /// by the system and defer the remaining fields by setting the stillPendingFields
        /// parameter in the completion handler.
        ///
        /// Error cases:
        /// ------------
        /// If the creation fails because the target directory does not exist, the extension
        /// must fail the creation using the NSFileProviderErrorNoSuchItem error code. In
        /// that case, the system will attempt the re-create the parent directory.
        ///
        /// In case the location of the new item is already in use by another item, the extension
        /// can chose to either resolve the collision by moving one of the items
        /// away, or reject the creation with the NSFileProviderErrorFilenameCollision
        /// error code. In that error case, the system will be responsible for resolving the
        /// collision, by renaming one of the colliding items. When the collision is resolved,
        /// the system will call createItemBasedOnTemplate again.
        ///
        /// The extension can also report NSFileProviderErrorNotAuthenticated,
        /// NSFileProviderErrorCannotSynchronize, or NSFileProviderErrorExcludedFromSync,
        /// in case the modification cannot be applied because of the current state of the
        /// system / domain. In that case, the system will present an appropriate error message
        /// and back off until the next time it is signalled. The provider can signal the error
        /// resolution by calling signalErrorResolved:completionHandler:.
        ///
        /// Any other error, including crashes of the extension process, will be considered to be transient
        /// and will cause the creation to be retried.
        ///
        /// Errors must be in one of the following domains: NSCocoaErrorDomain, NSFileProviderErrorDomain.
        ///
        /// For errors which can not be represented using an existing error code in one of these domains, the extension
        /// should construct an NSError with domain NSCocoaErrorDomain and code NSXPCConnectionReplyInvalid.
        /// The extension should set the NSUnderlyingErrorKey in the NSError's userInfo to the error which could not
        /// be represented.
        ///
        /// Cancellations:
        /// ------------
        /// If the NSProgress returned by this method is cancelled, the extension should
        /// call the completion handler with (nil, [], NO, NSUserCancelledError) in the NSProgress
        /// cancellation handler.
        ///
        /// Execution time:
        /// ---------------
        /// The system will grant enough time to the extension to upload the file if content is passed to the call,
        /// otherwise the call is expected to completed within a few seconds. The system will interrupt the
        /// call if it stops making progress or if upload takes an unexpectedly long time. In that case, the system
        /// will call `cancel` on the progress. The extension is then expected to quickly call the completion
        /// handler.
        #[unsafe(method(createItemBasedOnTemplate:fields:contents:options:request:completionHandler:))]
        #[unsafe(method_family = none)]
        unsafe fn createItemBasedOnTemplate_fields_contents_options_request_completionHandler(
            &self,
            item_template: &NSFileProviderItem,
            fields: NSFileProviderItemFields,
            url: Option<&NSURL>,
            options: NSFileProviderCreateItemOptions,
            request: &NSFileProviderRequest,
            completion_handler: &block2::DynBlock<
                dyn Fn(*mut NSFileProviderItem, NSFileProviderItemFields, Bool, *mut NSError),
            >,
        ) -> Retained<NSProgress>;

        #[cfg(all(
            feature = "NSFileProviderItem",
            feature = "NSFileProviderModifyItemOptions",
            feature = "NSFileProviderRequest",
            feature = "block2"
        ))]
        /// Informs the provider that an item or its metadata have changed. More than one
        /// property may have changed, e.g.  an item may have been renamed, moved and also
        /// changed contents, in which case changedFields might contain [.contents,
        /// .filename, .parentItemIdentifier, .contentModificationDate].
        ///
        /// If the provider is not able to apply all the fields at once, it should return a
        /// set of stillPendingFields in its completion handler. In that case, the system will
        /// attempt to modify the item later by calling modifyItem with those fields.
        ///
        /// The filename and contents fields should be synced together.
        /// If synced independently, files may appear corrupted on other devices, due to
        /// a mismatch between the file extension and the actual file data.
        ///
        /// Starting in macOS 12.0, if the set of stillPendingFields returned by the provider is
        /// identical to the set of fields passed to modifyItem, then the system will consider that these fields
        /// are not supported by the provider. The system will not send these fields to the provider again,
        /// until the item is modified.
        ///
        /// If a field in the returned item does not match the itemTemplate, and is
        /// not in the list of stillPendingFields, the value from the item will be
        /// propagated to the disk. In case there is a content change and the content of
        /// the returned item as described by item does not match the content from url,
        /// the provider should set shouldFetchContent in the completion handler. The
        /// content from the provider will then be fetched and propagated to disk.
        ///
        /// If the item modification results from the parent directory being merged into another
        /// directory, the NSFileProviderModifyItemMayAlreadyExist flag will be passed
        /// to the call.
        ///
        /// The provider can chose to merge two existing items when receiving modifyItem. In that
        /// case, the item returned should carry the itemIdentifier of the item with which the
        /// item will be merged and well as the resulting state of that item. The system will then
        /// keep one of the items (the one whose itemIdentifier was returned) and remove
        /// the other one from disk. In case of directories, the content of the two directories
        /// is merged and sub-items will be modified with the
        /// NSFileProviderModifyItemMayAlreadyExist flag set.
        ///
        /// If the extension wishes the modify item to cause the deletion of the item on disk,
        /// it can call the completion handler with nil in place of the resulting item. If the
        /// item is directory, the item will be kept on disk until all its children has been deleted
        /// from the working set. The system will only apply the deletion on the disk if this
        /// does not conflict with local edits. Otherwise, the system will attempt to re-create
        /// the item with the NSFileProviderCreateItemDeletionConflicted option set.
        ///
        /// The progress returned by modifyItem is expected to include the upload progress if any,
        /// even if the provider chose to call the completion handler before the upload finishes.
        /// For example, the provider might decide to call the completion handler as soon as the
        /// metadata have been stored in a local database.
        ///
        /// Modifications are gated by the corresponding capabilities of the item on a UI level,
        /// but direct file system changes (e.g. from Terminal) can still result in changes that
        /// must be handled.
        ///
        /// Conflict resolution:
        /// -------------------
        /// The system passes a `baseVersion` parameter to the modifyItem call. This
        /// baseVersion describes the latest version of the file which was reflected on disk.
        /// This parameter can be used to detect conflicts with remote edits.
        ///
        /// For instance, if content version A of the file was downloaded to the local system, and
        /// the content was modified locally, the modifyItem call will receive baseVersion of A. If the server
        /// has in the meantime received another content edit of the same file, the server may
        /// have content version C. In this case, the extension can detect the mismatching baseVersion,
        /// and decide how to resolve the conflict. The extension informs the system of how it
        /// wishes to resolve the conflict by returning the resolved metadata on the completion handler.
        /// As an example resolution, if the extension informs that it wishes for the remote version
        /// of the item to be on disk (and to ignore the local edits), it should return the new
        /// contentVersion in the completion handler's item. The system will subsequently call
        /// fetchContents to retrieve the new contents and replace them on disk.
        ///
        /// The `baseVersion` might contain one or both component set to
        /// `+[NSFileProviderItemVersion beforeFirstSyncComponent]`, in case
        /// there has never been a version for which the item on disk and the item in the provider
        /// were known to be in sync.
        ///
        /// Structural consistency and Cycle handling:
        /// ------------------------------------------
        /// In case the parentItemIdentifier is modified, the system guarantees that the new
        /// parent has been created and the creation completed before the call to modifyItem
        /// is issued.
        ///
        /// The system guarantees that modifyItem called after local changes from the user will
        /// never create a cycle: that is all items will always be a descendent of either the
        /// root item or the trash item.
        ///
        /// However, cycles that are caused by concurrent local changes by the user and changes
        /// on the remote server can also create cycles. This is handled by the system as a
        /// conflict. This means the provider must validate that the call of modifyItem is not
        /// creating a cycle with a change it observed from the server. If such a cycle is
        /// detected, the provider must fix the conflict by breaking the cycle, and return the
        /// state of the item after resolving that conflict. If the resolution affects other
        /// items as well, updates for those other items must be published on the working set.
        ///
        /// File ownership:
        /// ---------------
        /// The file at `url` is owned by the system and is unlinked after the completion
        /// handler is called. If the extension wishes to keep access to the content of
        /// file after calling the completion handler, it should clone the file in its
        /// container.
        ///
        /// Atomicity:
        /// ----------
        /// By default, the system assumes all the changes are applied non-atomically, which
        /// means that the change or an intermediary state from the change can be observed
        /// (for instance while enumerating the working set) while the call is in progress
        /// (before the completion handler is called). The provider can indicate to the system
        /// that it applies changes atomically (that is, the change cannot be observed before
        /// the completion handler is called) by setting the key NSExtensionFileProviderAppliesChangesAtomically
        /// in the Info.plist of the extension to YES.
        ///
        /// The atomicity declaration only describes the visibility of the changes, not
        /// the ability of the provider to apply all the fields at once: a provider that applies
        /// changes atomically might still apply a subset of the changedFields communicated
        /// by the system and defer the remaining fields by setting the stillPendingFields
        /// parameter in the completion handler.
        ///
        /// Error cases:
        /// ------------
        /// The extension may fail the modification if the modified item does not exist
        /// anymore. In that case, the extension should fail the call the
        /// NSFileProviderErrorNoSuchItem error code. The system will attempt to delete
        /// the item on disk. If the item on disk actually has changes since this call
        /// to modifyItem, then it will be re-created by a call to createItemBasedOnTemplate.
        /// Likewise, if the item is reparented to a parent that no longer exists, the extension
        /// may return a NSFileProviderErrorNoSuchItem error with the parent item.
        ///
        /// In case the modification updates the location of the item and another item is
        /// already known at this location, the extension can chose to either resolve the
        /// collision by moving one of the items away, or reject the modification with
        /// the NSFileProviderErrorFilenameCollision error code. In that error case,
        /// the system will be responsible for resolving the collision, by renaming one of
        /// the colliding items. When the collision is resolved, the system will call
        /// modifyItem again.
        ///
        /// In case the NSFileProviderModifyItemFailOnConflict option is passed, the provider should
        /// fail the modification if the baseVersion does not match the version on the server. It
        /// will be up to the system to merge the conflict and call modifyItem again with an
        /// updated baseVersion.
        ///
        /// The extension can also report NSFileProviderErrorNotAuthenticated,
        /// NSFileProviderErrorCannotSynchronize, or NSFileProviderErrorExcludedFromSync,
        /// in case the modification cannot be applied because of the current state of the
        /// system / domain. In that case, the system will present an appropriate error message
        /// and back off until the next time it is signalled. The provider can signal the error
        /// resolution by calling signalErrorResolved:completionHandler:.
        ///
        /// Any other error, including crashes of the extension process, will be considered to be transient
        /// and will cause the modification to be retried.
        ///
        /// Errors must be in one of the following domains: NSCocoaErrorDomain, NSFileProviderErrorDomain.
        ///
        /// For errors which can not be represented using an existing error code in one of these domains, the extension
        /// should construct an NSError with domain NSCocoaErrorDomain and code NSXPCConnectionReplyInvalid.
        /// The extension should set the NSUnderlyingErrorKey in the NSError's userInfo to the error which could not
        /// be represented.
        ///
        /// Cancellations:
        /// ------------
        /// If the NSProgress returned by this method is cancelled, the extension should
        /// call the completion handler with (nil, [], NO, NSUserCancelledError) in the NSProgress
        /// cancellation handler.
        ///
        /// Execution time:
        /// ---------------
        /// The system will grant enough time to the extension to upload the file if content is passed to the call,
        /// otherwise the call is expected to completed within a few seconds. The system will interrupt the
        /// call if it stops making progress or if upload takes an unexpectedly long time. In that case, the system
        /// will call `cancel` on the progress. The extension is then expected to quickly call the completion
        /// handler.
        #[unsafe(method(modifyItem:baseVersion:changedFields:contents:options:request:completionHandler:))]
        #[unsafe(method_family = none)]
        unsafe fn modifyItem_baseVersion_changedFields_contents_options_request_completionHandler(
            &self,
            item: &NSFileProviderItem,
            version: &NSFileProviderItemVersion,
            changed_fields: NSFileProviderItemFields,
            new_contents: Option<&NSURL>,
            options: NSFileProviderModifyItemOptions,
            request: &NSFileProviderRequest,
            completion_handler: &block2::DynBlock<
                dyn Fn(*mut NSFileProviderItem, NSFileProviderItemFields, Bool, *mut NSError),
            >,
        ) -> Retained<NSProgress>;

        #[cfg(all(
            feature = "NSFileProviderItem",
            feature = "NSFileProviderRequest",
            feature = "block2"
        ))]
        /// Delete an item forever.
        ///
        /// This is called when the user deletes an item that was already in the Trash and
        /// the item should no longer appear there after this call.  This call should
        /// remove the item from the working set.
        ///
        /// This call receives an optional baseVersion which represent the version of the
        /// item we are trying to delete.
        ///
        /// Unless the NSFileProviderDeleteItemRecursive options is passed, the
        /// deletion of a directory should be non-recursive. If the deletion is recursive
        /// the provider should take care of reporting the deletion of all the deleted
        /// items through the working set.
        ///
        /// Delete is gated by the capabilities of the removed item with
        /// NSFileProviderItemCapabilitiesAllowsDeleting.
        ///
        /// Modifications are gated by NSFileProviderItemCapabilitiesAllowsDeleting
        /// of the item on a UI level, but direct file system changes (e.g. from Terminal)
        /// can still result in changes that must be handled.
        ///
        /// Atomicity:
        /// ----------
        /// By default, the system assumes all the changes are applied non-atomically, which
        /// means that the change or an intermediary state from the change can be observed
        /// (for instance while enumerating the working set) while the call is in progress
        /// (before the completion handler is called). The provider can indicate to the system
        /// that it applies changes atomically (that is, the change cannot be observed before
        /// the completion handler is called) by setting the key NSExtensionFileProviderAppliesChangesAtomically
        /// in the Info.plist of the extension to YES.
        ///
        /// Error cases:
        /// ------------
        /// The extension may fail the deletion in different scenarios, for instance because
        /// the baseVersion is out of date or because the user does not have permissions to
        /// delete the item. In that case the extension should fail the call with the
        /// NSFileProviderErrorDeletionRejected error code which will cause the system to
        /// re-create the deleted item on disk based on the latest metadata available from
        /// the extension.
        ///
        /// If the options don't include NSFileProviderDeleteItemRecursive and the
        /// deletion targets a non-empty directory, the extension must reject the deletion
        /// with the NSFileProviderErrorDirectoryNotEmpty error code. This error can also
        /// be reported in case some children of the directory cannot be deleted when
        /// receiving the NSFileProviderDeleteItemRecursive option. In both cases,
        /// the system will re-create the deleted item on disk based on the latest metadata
        /// available from the extension.
        ///
        /// If the deletion targets an item that is unknown from the extension because
        /// that item may have already been deleted remotely, then the extension should
        /// report a success.
        ///
        /// The extension can also report the NSFileProviderErrorNotAuthenticated,
        /// NSFileProviderErrorServerUnreachable, or NSFileProviderErrorCannotSynchronize
        /// in case the deletion cannot be applied because of the current state of the
        /// system / domain. In that case, the system will present an appropriate error
        /// message and back off until the next time it is signalled.
        ///
        /// Any other error, including crashes of the extension process, will be considered to be transient
        /// and will cause the deletion to be retried.
        ///
        /// Errors must be in one of the following domains: NSCocoaErrorDomain, NSFileProviderErrorDomain.
        ///
        /// For errors which can not be represented using an existing error code in one of these domains, the extension
        /// should construct an NSError with domain NSCocoaErrorDomain and code NSXPCConnectionReplyInvalid.
        /// The extension should set the NSUnderlyingErrorKey in the NSError's userInfo to the error which could not
        /// be represented.
        ///
        /// Cancellations:
        /// ------------
        /// If the NSProgress returned by this method is cancelled, the extension should
        /// call the completion handler with (NSUserCancelledError) in the NSProgress
        /// cancellation handler.
        ///
        /// Execution time:
        /// ---------------
        /// This call is not expected to take more than a few seconds to complete. The system will interrupt the
        /// call if it stops making progress or if the deletion takes an unexpectedly long time. In that case,the system
        /// will call `cancel` on the progress. The extension is then expected to quickly call the completion
        /// handler.
        #[unsafe(method(deleteItemWithIdentifier:baseVersion:options:request:completionHandler:))]
        #[unsafe(method_family = none)]
        unsafe fn deleteItemWithIdentifier_baseVersion_options_request_completionHandler(
            &self,
            identifier: &NSFileProviderItemIdentifier,
            version: &NSFileProviderItemVersion,
            options: NSFileProviderDeleteItemOptions,
            request: &NSFileProviderRequest,
            completion_handler: &block2::DynBlock<dyn Fn(*mut NSError)>,
        ) -> Retained<NSProgress>;

        #[cfg(feature = "block2")]
        /// Signal the end of import of on-disk items.
        ///
        /// This is called after a reimport of on-disk items has been triggered by either
        /// `-[NSFileProviderManager reimportItemsBelowItemWithIdentifier:completionHandler:]`
        /// or after a new domain is created using
        /// `+[NSFileProviderManager importDomain:fromDirectoryAtURL:completionHandler:]` or
        /// `+[NSFileProviderManager addDomain:completionHandler:]`.
        ///
        /// `reimport` can also be started by the system independently from any request by the
        /// provider. The provider can detect those events by monitoring
        /// `-[NSFileProviderDomain backingStoreIdentity]`.
        ///
        /// During import, found items will be created via the
        /// -[NSFileProviderExtension createItemBasedOnTemplate:fields:contents:options:completionHandler:]
        /// call with the NSFileProviderCreateItemMayAlreadyExist flag set.
        /// At the end of an import the -[NSFileProviderExtension importDidFinishWithCompletionHandler:]
        /// is called.
        ///
        /// The system will attempt to import items as they are accessed by the user or applications. Import
        /// of the other items is scheduled by the system as a background task. That task may be delayed,
        /// for instance in low-power situations, or when the system is under heavy load. The provider can
        /// force the system to process a folder and its direct children by issuing a coordination request
        /// on that folder.
        ///
        /// Execution time:
        /// ---------------
        /// This call is not expected to take more than a few seconds to complete.
        #[optional]
        #[unsafe(method(importDidFinishWithCompletionHandler:))]
        #[unsafe(method_family = none)]
        unsafe fn importDidFinishWithCompletionHandler(
            &self,
            completion_handler: &block2::DynBlock<dyn Fn()>,
        );

        #[cfg(feature = "block2")]
        /// Called by the system if the set of materialized items changes.
        ///
        /// Materialized items are items that have synced to disk and are not
        /// dataless.  They may contain a mix of dataless and materialized files and
        /// directories, but in any case, all their children are represented on disk.
        /// Traversals of dataless directories by applications trigger an enumeration
        /// against the file provider extension; traversals of materialized directories
        /// do not.  It is the responsability of the file provider extension to notify
        /// the system on remote changes of these files: there is no alternative cache
        /// invalidation mechanism.
        ///
        /// If the extension doesn't keep track of the materialized set, it will have to
        /// notify the system of all remote changes.  In that case the working set is the
        /// entire dataset.  The system may drop items whose parent isn't materialized, to
        /// avoid unnecessary disk usage.  This saves some I/O, but isn't optimal.  The
        /// filtering by parentItemIdentifier is better done in the extension;  ideally,
        /// it would even be done server-side.  A hybrid model is possible, where some
        /// filtering is done server-side, and some finer filtering is done client-side.
        ///
        /// The file provider extension should therefore keep a list of the identifiers of
        /// the materialized directories.  This method is called when a new directory is
        /// materialized or when a materialized directory is rendered dataless.
        ///
        /// To enumerate the set of materialized containers,
        /// - Call -enumeratorForMaterializedItems on the instance of
        /// NSFileProviderManager corresponding to your domain;
        /// - Implement the NSFileProviderEnumerationObserver and
        /// NSFileProviderChangeObserver on an object;
        /// - Pass that object to the enumerator;
        /// - Use the identifiers of items or changes you receive to note the
        /// materialization status in your database.
        ///
        /// When an item is created, modified or deleted remotely, the file provider
        /// extension should check whether its parentItemIdentifier is in the materialized
        /// set.  If it is, the extension needs to inform the system so the system may
        /// create, modify or delete the file or directory (initially dataless) on disk.
        /// In the case when an item is reparented, the test should be that either the new
        /// or the old parentItemIdentifier is in the materialized set.  No need to pretend
        /// that the iten was deleted if the new parentItemIdentifier is no longer in the
        /// materialized set: the system will know what to do with an unknown parent
        /// identifier.
        ///
        /// To notify the system of this created, modified or deleted item,
        /// - Call -signalEnumeratorForContainerItemIdentifier: on the working set, i.e the
        /// container identified by NSFileProviderWorkingSetContainerItemIdentifier;
        /// - Include this item in the next enumeration of the working set.
        ///
        /// Since this method is called on every change of the set of materialized items,
        /// it is advisable to use it to set a flag and perform any resulting work as a
        /// timed task rather than performing any work directly.
        ///
        /// Execution time:
        /// ---------------
        /// This call is not expected to take more than a few seconds to complete.
        #[optional]
        #[unsafe(method(materializedItemsDidChangeWithCompletionHandler:))]
        #[unsafe(method_family = none)]
        unsafe fn materializedItemsDidChangeWithCompletionHandler(
            &self,
            completion_handler: &block2::DynBlock<dyn Fn()>,
        );

        #[cfg(feature = "block2")]
        /// Called by the system when the set of pending items is refreshed.
        ///
        /// The pending enumerator lists all the items for which a change has been observed either
        /// on the disk or in the working set more than one second ago and that change hasn't been
        /// applied on the other side yet. An item can appear in the pending set for various reasons:
        /// - the system is under load and cannot process all the events in a timely fashion
        /// - a long running operation is scheduled or running for the item to be in sync (for instance,
        /// the download or the upload of a new content)
        /// - an error occurred, in which case the error will be set on the item as `downloadError` if
        /// it occurred when applying a change to the disk, or `uploadError` in the other way around.
        ///
        /// The pending set will only include items that comply to the following rules:
        /// - They have been queued for changes for more time than the refresh interval;
        /// - The items are already known by the provider.
        ///
        /// These constraints imply that initial transfer of a file from the disk to the provider will not
        /// be listed in the pending set, even though the transfer could take several minutes to complete
        ///
        /// Furthermore, the pending set can only contain a limited number of items.
        /// The pending set provides an easy way to design an "in progress" UI containing a few items
        /// and to detect whether there's any activity pending on the system.
        /// In case the pending set reached its maximum size items, newly pending items won't be included
        /// in it. Already present items in the pending set will remain until they no longer are pending.
        ///
        /// The pending set is refreshed regurlary but only if there are meaningful changes:
        /// new pending items, items that were pending but are not anymore (deletions from the set),
        /// or domain version changed and set is not empty
        ///
        /// To enumerate the set of pending items,
        /// - Call -enumeratorForPendingItems on the instance of
        /// NSFileProviderManager corresponding to your domain;
        /// - Implement the NSFileProviderEnumerationObserver and
        /// NSFileProviderChangeObserver on an object;
        /// - Pass that object to the enumerator;
        /// - It will get called upon change to the set.
        ///
        /// This method is regularly called when changes happen to the pending set.
        /// implementeers are advised that this call will not happen as soon as an item is pending.
        /// Thus, implementeers should not use the pending set to detect when a change happens.
        /// The pending set will only contain items that were pending for a least one second before the
        /// last refresh date.
        ///
        /// Execution time:
        /// ---------------
        /// This call is not expected to take more than a few seconds to complete.
        #[optional]
        #[unsafe(method(pendingItemsDidChangeWithCompletionHandler:))]
        #[unsafe(method_family = none)]
        unsafe fn pendingItemsDidChangeWithCompletionHandler(
            &self,
            completion_handler: &block2::DynBlock<dyn Fn()>,
        );
    }
);

extern_protocol!(
    /// Protocol to implement if the provider instance supports fetching incremental content changes.
    ///
    /// See also [Apple's documentation](https://developer.apple.com/documentation/fileprovider/nsfileproviderincrementalcontentfetching?language=objc)
    pub unsafe trait NSFileProviderIncrementalContentFetching: NSObjectProtocol {
        #[cfg(all(
            feature = "NSFileProviderItem",
            feature = "NSFileProviderRequest",
            feature = "block2"
        ))]
        /// Update a previously provided item to a new version.
        ///
        /// If the system already has a version of an item and learns that a new version is
        /// available, it may call this method to update the existing version to a new
        /// version.
        ///
        /// The semantics of the requestedVersion parameter are the same as for the non-delta update method above.
        #[unsafe(method(fetchContentsForItemWithIdentifier:version:usingExistingContentsAtURL:existingVersion:request:completionHandler:))]
        #[unsafe(method_family = none)]
        unsafe fn fetchContentsForItemWithIdentifier_version_usingExistingContentsAtURL_existingVersion_request_completionHandler(
            &self,
            item_identifier: &NSFileProviderItemIdentifier,
            requested_version: Option<&NSFileProviderItemVersion>,
            existing_contents: &NSURL,
            existing_version: &NSFileProviderItemVersion,
            request: &NSFileProviderRequest,
            completion_handler: &block2::DynBlock<
                dyn Fn(*mut NSURL, *mut NSFileProviderItem, *mut NSError),
            >,
        ) -> Retained<NSProgress>;
    }
);

extern_protocol!(
    /// [Apple's documentation](https://developer.apple.com/documentation/fileprovider/nsfileproviderservicing?language=objc)
    pub unsafe trait NSFileProviderServicing: NSObjectProtocol {
        #[cfg(all(
            feature = "NSFileProviderItem",
            feature = "NSFileProviderService",
            feature = "block2"
        ))]
        /// A file provider can implemement this method to return service sources that provide custom
        /// communication channels to client applications.
        ///
        /// The service sources must be tied to the item identified by
        /// `itemIdentifier.`Client applications can retrieve the list of supported services by calling
        /// `-[NSFileManager`getFileProviderServicesForItemAtURL:] for a specific item URL.
        ///
        /// Cancellations:
        /// ------------
        /// If the NSProgress returned by this method is cancelled, the extension should
        /// call the completion handler with (nil, NSUserCancelledError) in the NSProgress
        /// cancellation handler.
        ///
        /// Execution time:
        /// ---------------
        /// This method is not expected to take more than a few seconds to complete the retrieval of the
        /// thumbnails. The system will call `cancel` on the progress if the
        /// operation takes too much time. The extension is then expected to quickly call the completion
        /// handler.
        #[unsafe(method(supportedServiceSourcesForItemIdentifier:completionHandler:))]
        #[unsafe(method_family = none)]
        unsafe fn supportedServiceSourcesForItemIdentifier_completionHandler(
            &self,
            item_identifier: &NSFileProviderItemIdentifier,
            completion_handler: &block2::DynBlock<
                dyn Fn(*mut NSArray<ProtocolObject<dyn NSFileProviderServiceSource>>, *mut NSError),
            >,
        ) -> Retained<NSProgress>;
    }
);

extern_protocol!(
    /// Protocol to implement if the provider supports fetching thumbnails for its items.
    ///
    /// See also [Apple's documentation](https://developer.apple.com/documentation/fileprovider/nsfileproviderthumbnailing?language=objc)
    pub unsafe trait NSFileProviderThumbnailing: NSObjectProtocol {
        #[cfg(all(
            feature = "NSFileProviderItem",
            feature = "block2",
            feature = "objc2-core-foundation"
        ))]
        /// The system calls this method to fetch thumbnails.
        ///
        /// The
        /// `perThumbnailCompletionHandler`should be called for each thumbnail, and
        /// `completionHandler`only after all the per thumbnail completion blocks.
        ///
        /// In the event of a global error, the implementation is allowed to skip calling
        /// the
        /// `perThumbnailCompletionHandler`for individual thumbnails. In that case,
        /// the
        /// `completionHandler's`error parameter would apply to all item identifiers
        /// for which
        /// `perThumbnailCompletionHandler`had not been called.
        ///
        /// If there is no thumbnail for a given item, the
        /// `perThumbnailCompletionHandler`should be called with its
        /// `imageData`and
        /// `error`parameters both
        /// set to nil.
        ///
        /// If the system decides that an in-flight thumbnail request is not needed anymore,
        /// it will call the returned
        /// `NSProgress`object's
        /// `-cancel`method,
        /// at which time the implementation should clean up any held resources.
        ///
        /// The system will cache the thumbnail for the item, and the cache will be
        /// invalidated when itemVersion.contentVersion changes.
        ///
        /// Thread safety:
        /// ------------
        ///
        /// The
        /// `perThumbnailCompletionHandler`may be called from multiple threads
        /// concurrently.
        ///
        /// Cancellations:
        /// ------------
        /// If the NSProgress returned by this method is cancelled, the extension should
        /// call the completion handler with (NSUserCancelledError) in the NSProgress
        /// cancellation handler.
        ///
        /// Execution time:
        /// ---------------
        /// This method is not expected to take more than a few tens seconds to complete the retrieval of the
        /// services exposed on the item. The system will call `cancel` on the progress if the
        /// operation takes too much time. The extension is then expected to quickly call the completion
        /// handler.
        #[unsafe(method(fetchThumbnailsForItemIdentifiers:requestedSize:perThumbnailCompletionHandler:completionHandler:))]
        #[unsafe(method_family = none)]
        unsafe fn fetchThumbnailsForItemIdentifiers_requestedSize_perThumbnailCompletionHandler_completionHandler(
            &self,
            item_identifiers: &NSArray<NSFileProviderItemIdentifier>,
            size: CGSize,
            per_thumbnail_completion_handler: &block2::DynBlock<
                dyn Fn(NonNull<NSFileProviderItemIdentifier>, *mut NSData, *mut NSError),
            >,
            completion_handler: &block2::DynBlock<dyn Fn(*mut NSError)>,
        ) -> Retained<NSProgress>;
    }
);

extern_protocol!(
    /// [Apple's documentation](https://developer.apple.com/documentation/fileprovider/nsfileprovidercustomaction?language=objc)
    pub unsafe trait NSFileProviderCustomAction: NSObjectProtocol {
        #[cfg(all(
            feature = "NSFileProviderActions",
            feature = "NSFileProviderItem",
            feature = "block2"
        ))]
        /// Perform a custom action identified by `actionIdentifier`, on items identified by
        /// `itemIdentifiers`.
        ///
        /// Custom actions are defined in the File Provider Extension's Info.plist, under the
        /// `NSExtensionFileProviderActions` key. The format of this key is identical to actions
        /// defined in a FileProviderUI extension.
        ///
        /// Cancellations:
        /// ------------
        /// If the NSProgress returned by this method is cancelled, the extension should
        /// call the completion handler with (NSUserCancelledError) in the NSProgress
        /// cancellation handler.
        #[unsafe(method(performActionWithIdentifier:onItemsWithIdentifiers:completionHandler:))]
        #[unsafe(method_family = none)]
        unsafe fn performActionWithIdentifier_onItemsWithIdentifiers_completionHandler(
            &self,
            action_identifier: &NSFileProviderExtensionActionIdentifier,
            item_identifiers: &NSArray<NSFileProviderItemIdentifier>,
            completion_handler: &block2::DynBlock<dyn Fn(*mut NSError)>,
        ) -> Retained<NSProgress>;
    }
);

extern_protocol!(
    /// Protocol to implement for managing UserInteraction alerts.
    ///
    /// See also [Apple's documentation](https://developer.apple.com/documentation/fileprovider/nsfileprovideruserinteractionsuppressing?language=objc)
    pub unsafe trait NSFileProviderUserInteractionSuppressing: NSObjectProtocol {
        /// Suppression management:
        ///
        /// The extension may choose to give the user the option to suppress certain UserInteraction alerts.
        /// In order to do so, the extension must both implement NSFileProviderUserInteractionSuppressing, as well as
        /// configure the desired UserInteractions in the Info.plist with the `SuppressionIdentifier` field.
        ///
        /// When FileProvider needs to evaluate whether to display a UserInteraction alert, it will call
        /// -[NSFileProviderUserInteractionSuppressing isInteractionSuppressedForIdentifier:]. When the user indicates that they do not
        /// wish to see a given SuppressionIdentifiers's alert again, FileProvider will call
        /// -[NSFileProviderUserInteractionSuppressing setInteractionSuppressed:forIdentifier:].
        ///
        /// The extension can choose whether the suppression should apply only to the domain upon which
        /// -[NSFileProviderUserInteractionSuppressing setInteractionSuppressed:forIdentifier:] was called, or if it should apply to all
        /// domains for their provider. For instance, the extension could choose to suppress future alerts related
        /// to adding an item to a shared folder across all domains, after the user chooses to suppress the alerts
        /// in a specific domain's context. Or, the extension could choose to only suppress that alert for the
        /// specific domain it was displayed within, and in the future, the user would see the same alert in the same
        /// context, if they take the same action in another domain.
        ///
        /// Execution time:
        /// ---------------
        /// This method is expected to complete immediately.
        #[unsafe(method(setInteractionSuppressed:forIdentifier:))]
        #[unsafe(method_family = none)]
        unsafe fn setInteractionSuppressed_forIdentifier(
            &self,
            suppression: bool,
            suppression_identifier: &NSString,
        );

        #[unsafe(method(isInteractionSuppressedForIdentifier:))]
        #[unsafe(method_family = none)]
        unsafe fn isInteractionSuppressedForIdentifier(
            &self,
            suppression_identifier: &NSString,
        ) -> bool;
    }
);

extern_protocol!(
    /// [Apple's documentation](https://developer.apple.com/documentation/fileprovider/nsfileproviderdomainstate?language=objc)
    pub unsafe trait NSFileProviderDomainState: NSObjectProtocol {
        #[cfg(feature = "NSFileProviderDomain")]
        /// Version of the domain.
        ///
        /// The domain version is an opaque value assigned by the provider. It is read by the system in the
        /// completion handler for createItemBasedOnTemplate, modifyItem, deleteItem and itemForIdentifier, as
        /// well as in the finish calls when enumerating the working set. The read is guaranteed to happen
        /// on the same dispatch queue the completion handler was called on.
        ///
        /// When the system discovers a change on disk, it associates that change to the currently known
        /// domain version. When that change get communicated to the extension, that version is included in
        /// the NSFileProviderRequest object passed by the system to the extension. As a consequence, the
        /// provider can use the domain version to identify the state of the system when a change was made on disk.
        ///
        /// The provider is responsible for defining when the domain version changes. When that value is
        /// updated, the provider must notify the system by signaling the working set.
        ///
        /// The system ignore any domain version that is smaller than the previously known version.
        #[unsafe(method(domainVersion))]
        #[unsafe(method_family = none)]
        unsafe fn domainVersion(&self) -> Retained<NSFileProviderDomainVersion>;

        /// Global state of the domain.
        ///
        /// Use this dictionary to add state information to the domain. It is accessible to predicates for
        /// User Interactions, FileProvider Actions, and FileProviderUI Actions, via the top-level `domainUserInfo` context
        /// key.
        ///
        /// This dictionary must only contain key and value classes in the following list:
        /// NSString, NSNumber, NSDate, and NSPersonNameComponents.
        ///
        /// The system expects the domainVersion to be updated when the value of the userInfo property
        /// changes.
        #[unsafe(method(userInfo))]
        #[unsafe(method_family = none)]
        unsafe fn userInfo(&self) -> Retained<NSDictionary>;
    }
);

extern_protocol!(
    /// [Apple's documentation](https://developer.apple.com/documentation/fileprovider/nsfileproviderpartialcontentfetching?language=objc)
    pub unsafe trait NSFileProviderPartialContentFetching: NSObjectProtocol {
        #[cfg(all(
            feature = "NSFileProviderItem",
            feature = "NSFileProviderRequest",
            feature = "block2"
        ))]
        /// Download the requested extent of an item for the given identifier and return it via the completion
        /// handler.  If this protocol is not implemented the system defaults to fetchContentsForItemWithIdentifier.
        ///
        /// The requestedVersion parameter specifies which version should be returned. This version will always be
        /// specified by the system so as to prevent extents from different versions from being written into the same
        /// file. The system tolerates a version mismatch for the first materialization of a fully dataless file (strictVersion=NO).
        ///
        /// The requested range is
        /// <location
        /// , length>.  The implementation can provide any properly aligned range that
        /// covers the requested range (including the entire item).  The system provides the minimal alignment value.
        /// The location (or start offset) of the fetched range should be a multiple of this value for it to be considered
        /// properly aligned. The length of the fetched range should be a multiple of this value, with an exception for
        /// the end of the file, checked against the documentSize attribute the implementation supplied for this item.
        /// The alignment value should not be expected to be stable across reboots. It is guaranteed by the system to be
        /// a power of two.
        /// In addition to the content the extension needs to fill in fetchedRange with either the requestest range,
        /// <location
        /// , length>, or indicate full materialization with,
        /// <
        /// 0, file size>.
        ///
        /// On-disk layout:
        /// ---------------
        /// The retrieved content at `fileContents` URL must be a regular file on the same volume as the user-visible URL.
        /// A suitable location can be retrieved using -[NSFileProviderManager temporaryDirectoryURLWithError:].
        /// The file contents outside of the fetched range are ignored by the system. The system only requires the file
        /// to be at least as large as the end of the fetched range. For instance, if the fetchedRange is {offset:0x100000, length:0x1000},
        /// the file size must be at least 0x101000 bytes. Any data (or lack thereof) beyond the fetched range is ignored.
        ///
        /// The fetched range must be stored in this file at the same offset as the range indicates.
        /// For instance if the retrievedRange  is {offset:0x100000, length:0x1000} then it should actually be at offset 0x100000 in the
        /// `fileContents` file. The ranges {0, 0x100000}, and {0x101000, EOF} can be anything including sparse ranges.
        ///
        /// Concurrent Downloads:
        /// ---------------
        /// The system will call fetchContents concurrently if there are multiple outstanding file download requests.
        /// The provider can control the concurrency by setting the key NSExtensionFileProviderDownloadPipelineDepth
        /// in the Info.plist of the extension to the number of concurrent downloads that the system should create
        /// per domain. This number must be between 1 and 128, inclusive.
        ///
        /// File ownership:
        /// ---------------
        /// The system clones and unlinks the received fileContents. The extension should not mutate the corresponding
        /// file after calling the completion handler. If the extension wishes to keep a copy of the content, it must
        /// provide a clone of the that content as the URL passed to the completion handler.
        ///
        /// In case the extension or the system crashes between the moment the completion handler is called and the
        /// moment the system unlinks the file, the file may unexpectedly still be on disk the next time an instance
        /// of the extension is created. The extension is then responsible for deleting that file.
        ///
        /// Disallowing processes from fetching items:
        /// ---------------
        ///
        /// The system automatically downloads files on POSIX accesses. The extension may wish to disallow this class of
        /// downloads for specific applications.
        ///
        /// The extension can set an array of strings into the UserDefault key
        /// "NSFileProviderExtensionNonMaterializingProcessNames". A process whose executable's filename on disk is an
        /// exact match for an entry in this array will not be allowed to fetch items in the extension's domains. The comparison
        /// is case sensitive.
        ///
        /// In macOS 11.0 and later, this list will be checked when a download is initiated through a POSIX filesystem call.
        /// In macOS 11.4 and later, this list will also be checked for downloads initiated through file coordination.
        ///
        /// Error cases:
        /// ------------
        /// If the download fails because the item is unknown, the call should
        /// fail with the NSFileProviderErrorNoSuchItem error. In that case, the system
        /// will consider the item has been removed from the domain and will attempt to
        /// delete it from disk. In case that deletion fails because there are local
        /// changes on this item, the system will re-create the item using createItemBasedOnTemplate.
        ///
        /// If the user does not have access to the content of the file, the provider
        /// can fail the call with NSCocoaErrorDomain and code NSFileReadNoPermissionError.
        /// That error will then be presented to the user. The extension can also report
        /// the NSFileProviderErrorNotAuthenticated, NSFileProviderErrorServerUnreachable
        /// in case the item cannot be fetched because of the current state of the system / domain.
        /// In those cases, the system will present an appropriate error message and back off
        /// until the next time it is signalled.
        ///
        /// If the requested version cannot be retrieved, the provider can choose to provide a different
        /// version of the file, unless NSFileProviderFetchContentsOptionsStrictVersioning  is set. In this case,
        /// the provider should fail with NSFileProviderErrorVersionNoLongerAvailable.
        /// If some content is returned, the item must have the corresponding version. The system will detect
        /// any mismatch and handle it as a remote update.
        /// For the reading application, the materialization will fail with the same error as reading from
        /// a dataless file that got remotely updated (-1/errno=ESTALE). Upon retry the new version will be
        /// requested by the system.
        ///
        /// Any other error will be considered to be transient and will cause the
        /// download to be retried.
        ///
        /// Cancellations:
        /// ------------
        /// If the NSProgress returned by this method is cancelled, the extension should
        /// call the completion handler with (nil, nil, someRange, 0, NSUserCancelledError) in the NSProgress
        /// cancellation handler.
        ///
        /// The returned NSProgress is used to show progress to the user. If the user cancels the
        /// fetch, the extension should stop fetching the item, as it is no longer required.
        ///
        /// Execution time:
        /// ---------------
        /// The system will grant enough time to the extension to download the file. The system will interrupt the
        /// call if it stops making progress or if download takes an unexpectedly long time. In that case, the system
        /// will call `cancel` on the progress. The extension is then expected to quickly call the completion
        /// handler.
        #[unsafe(method(fetchPartialContentsForItemWithIdentifier:version:request:minimalRange:aligningTo:options:completionHandler:))]
        #[unsafe(method_family = none)]
        unsafe fn fetchPartialContentsForItemWithIdentifier_version_request_minimalRange_aligningTo_options_completionHandler(
            &self,
            item_identifier: &NSFileProviderItemIdentifier,
            requested_version: &NSFileProviderItemVersion,
            request: &NSFileProviderRequest,
            requested_range: NSRange,
            alignment: NSUInteger,
            options: NSFileProviderFetchContentsOptions,
            completion_handler: &block2::DynBlock<
                dyn Fn(
                    *mut NSURL,
                    *mut NSFileProviderItem,
                    NSRange,
                    NSFileProviderMaterializationFlags,
                    *mut NSError,
                ),
            >,
        ) -> Retained<NSProgress>;
    }
);

extern_protocol!(
    /// [Apple's documentation](https://developer.apple.com/documentation/fileprovider/nsfileproviderexternalvolumehandling?language=objc)
    pub unsafe trait NSFileProviderExternalVolumeHandling: NSObjectProtocol {
        #[cfg(feature = "block2")]
        /// Implement this protocol on your extension's Principal Class in order for the system
        /// to ask your extension whether a domain located on an external volume should be connected.
        ///
        /// Your extension may use this method as an opportunity to check for, and setup if necessary,
        /// state to operate the extension. Such as prompting the user to login in your application.
        /// When creating domains on external drive, store state related to the domain in the `userInfo` parameter to
        /// `-[NSFileProviderDomain initWithDisplayName:userInfo:volumeURL:]`,
        /// such as the user's ID, to help your extension identify the domain when connected on other devices. This userInfo will be
        /// persisted on the external volume, and provided in the ReplicatedExtension initializer when the drive is connected to a new device.
        ///
        /// If your extension responds with an NSError, the domain will be in a disconnected state. Non-downloaded files
        /// in the domain will not be downloadable, and file edits will not be synced up. The system will display
        /// UI to inform the user. Your extension will be able to enumerate this domain in
        /// `+[NSFileProviderManager getDomainsWithCompletionHandler:]`, with the
        /// `-[NSFileProviderDomain disconnected]` property set as YES.
        ///
        /// If at a later point, the user has setup the necessary state to service requests for the disconnected external
        /// domain, your extension may call `-[NSFileProviderManager reconnectWithCompletionHandler:]`.
        ///
        /// If your extension does not implement this protocol, domains on external volumes will automatically be
        /// connected and instantiated in your extension.
        #[unsafe(method(shouldConnectExternalDomainWithCompletionHandler:))]
        #[unsafe(method_family = none)]
        unsafe fn shouldConnectExternalDomainWithCompletionHandler(
            &self,
            completion_handler: &block2::DynBlock<dyn Fn(*mut NSError)>,
        );
    }
);