Trait Vfs 

pub trait Vfs: Send + Sync {
    type Handle: VfsHandle;

    // Required methods
    fn open(
        &self,
        path: Option<&str>,
        opts: OpenOpts,
    ) -> VfsResult<Self::Handle>;
    fn delete(&self, path: &str) -> VfsResult<()>;
    fn access(&self, path: &str, flags: AccessFlags) -> VfsResult<bool>;
    fn file_size(&self, handle: &mut Self::Handle) -> VfsResult<usize>;
    fn truncate(&self, handle: &mut Self::Handle, size: usize) -> VfsResult<()>;
    fn write(
        &self,
        handle: &mut Self::Handle,
        offset: usize,
        data: &[u8],
    ) -> VfsResult<usize>;
    fn read(
        &self,
        handle: &mut Self::Handle,
        offset: usize,
        data: &mut [u8],
    ) -> VfsResult<usize>;
    fn lock(&self, handle: &mut Self::Handle, level: LockLevel) -> VfsResult<()>;
    fn unlock(
        &self,
        handle: &mut Self::Handle,
        level: LockLevel,
    ) -> VfsResult<()>;
    fn check_reserved_lock(&self, handle: &mut Self::Handle) -> VfsResult<bool>;
    fn close(&self, handle: Self::Handle) -> VfsResult<()>;

    // Provided methods
    fn canonical_path<'a>(&self, path: Cow<'a, str>) -> VfsResult<Cow<'a, str>> { ... }
    fn sync(&self, handle: &mut Self::Handle) -> VfsResult<()> { ... }
    fn pragma(
        &self,
        handle: &mut Self::Handle,
        pragma: Pragma<'_>,
    ) -> Result<Option<String>, PragmaErr> { ... }
    fn sector_size(&self, handle: &mut Self::Handle) -> VfsResult<i32> { ... }
    fn device_characteristics(
        &self,
        handle: &mut Self::Handle,
    ) -> VfsResult<i32> { ... }
    fn shm_map(
        &self,
        handle: &mut Self::Handle,
        region_idx: usize,
        region_size: usize,
        extend: bool,
    ) -> VfsResult<Option<NonNull<u8>>> { ... }
    fn shm_lock(
        &self,
        handle: &mut Self::Handle,
        offset: u32,
        count: u32,
        mode: ShmLockMode,
    ) -> VfsResult<()> { ... }
    fn shm_barrier(&self, handle: &mut Self::Handle) { ... }
    fn shm_unmap(
        &self,
        handle: &mut Self::Handle,
        delete: bool,
    ) -> VfsResult<()> { ... }
    fn fetch(
        &self,
        handle: &mut Self::Handle,
        offset: i64,
        amt: usize,
    ) -> VfsResult<Option<NonNull<u8>>> { ... }
    fn unfetch(
        &self,
        handle: &mut Self::Handle,
        offset: i64,
        ptr: *mut u8,
    ) -> VfsResult<()> { ... }
}

Required Associated Types

type Handle: VfsHandle

Required Methods

fn open(&self, path: Option<&str>, opts: OpenOpts) -> VfsResult<Self::Handle>

fn delete(&self, path: &str) -> VfsResult<()>

fn access(&self, path: &str, flags: AccessFlags) -> VfsResult<bool>

fn file_size(&self, handle: &mut Self::Handle) -> VfsResult<usize>

fn truncate(&self, handle: &mut Self::Handle, size: usize) -> VfsResult<()>

fn write( &self, handle: &mut Self::Handle, offset: usize, data: &[u8], ) -> VfsResult<usize>

fn read( &self, handle: &mut Self::Handle, offset: usize, data: &mut [u8], ) -> VfsResult<usize>

fn lock(&self, handle: &mut Self::Handle, level: LockLevel) -> VfsResult<()>

fn unlock(&self, handle: &mut Self::Handle, level: LockLevel) -> VfsResult<()>

fn check_reserved_lock(&self, handle: &mut Self::Handle) -> VfsResult<bool>

fn close(&self, handle: Self::Handle) -> VfsResult<()>

Provided Methods

fn canonical_path<'a>(&self, path: Cow<'a, str>) -> VfsResult<Cow<'a, str>>

construct a canonical version of the given path

fn sync(&self, handle: &mut Self::Handle) -> VfsResult<()>

fn pragma( &self, handle: &mut Self::Handle, pragma: Pragma<'_>, ) -> Result<Option<String>, PragmaErr>

fn sector_size(&self, handle: &mut Self::Handle) -> VfsResult<i32>

fn device_characteristics(&self, handle: &mut Self::Handle) -> VfsResult<i32>

fn shm_map( &self, handle: &mut Self::Handle, region_idx: usize, region_size: usize, extend: bool, ) -> VfsResult<Option<NonNull<u8>>>

fn shm_lock( &self, handle: &mut Self::Handle, offset: u32, count: u32, mode: ShmLockMode, ) -> VfsResult<()>

fn shm_barrier(&self, handle: &mut Self::Handle)

fn shm_unmap(&self, handle: &mut Self::Handle, delete: bool) -> VfsResult<()>

fn fetch( &self, handle: &mut Self::Handle, offset: i64, amt: usize, ) -> VfsResult<Option<NonNull<u8>>>

Memory-mapped page read (xFetch). Return a pointer to amt bytes of the file starting at offset, or Ok(None) to decline and have SQLite fall back to xRead.

The default implementation declines all mmap requests. Override this to enable memory-mapped I/O for your VFS (e.g. mmap the database file).

Safety contract

The returned pointer must remain valid until unfetch is called with the same offset. SQLite may read from the pointer concurrently from multiple threads.

fn unfetch( &self, handle: &mut Self::Handle, offset: i64, ptr: *mut u8, ) -> VfsResult<()>

Release a memory-mapped page previously returned by fetch.

If ptr is null, this is a hint that the VFS should reduce its memory-mapped footprint (SQLite calls this when shrinking mmap). The default implementation is a no-op.

Implementors