thruput_sdk/storage/
flags.rs

1//! Storage flags on leaf handles.
2//!
3//! A handle's exclusive access mode (from `at_mut_exclusive`, `set_exclusive`
4//! or `delete_exclusive`) is a write policy: each successful write through it
5//! is followed by a request for `ExclusiveLock`. Building, reading and
6//! dropping a handle leave the host's flags alone, and writes through an
7//! ordinary handle never remove them, so a lock taken once lasts for the rest
8//! of the transaction unless [`clear_flags`](Flaggable::clear_flags) removes
9//! it. See [`sys_result::flags`](crate::sys_result::flags).
10
11use super::sealed::Sealed;
12use crate::StorageFlags;
13use crate::types::StorageKey;
14
15/// A leaf handle whose key's storage flags can be read and changed.
16///
17/// Implemented by `Value`, `NNInt`, `Balance` and `Bytestring`. Sealed, like
18/// [`StorageType`](super::StorageType).
19#[allow(private_bounds)]
20pub trait Flaggable: Sealed {
21    /// The storage key the flags belong to.
22    #[doc(hidden)]
23    fn storage_key(&self) -> &StorageKey;
24
25    /// The storage flags the current transaction requests for this key, as
26    /// seen by the current call frame:
27    /// [`ExclusiveLock`](StorageFlags::ExclusiveLock) once an exclusive write
28    /// or [`set_flags`](Self::set_flags) has asked for it, until
29    /// [`clear_flags`](Self::clear_flags). A key with no pending write has
30    /// none.
31    fn flags(&self) -> StorageFlags {
32        crate::sys_exn::flags::storage_flags(self.storage_key())
33    }
34
35    /// Adds `flags` (a bitwise OR) to the key's storage flags. Later writes
36    /// through any handle keep them.
37    ///
38    /// Throws unless a write to the key is pending in the current call frame:
39    /// one made here, or inherited from a caller or a successful callee. A
40    /// value that only exists from an earlier block does not count.
41    fn set_flags(&mut self, flags: StorageFlags) {
42        crate::sys_exn::flags::set_storage_flags(self.storage_key(), flags)
43    }
44
45    /// Removes every storage flag from the key. Does nothing if no write to
46    /// it is pending.
47    fn clear_flags(&mut self) {
48        crate::sys_exn::flags::clear_storage_flags(self.storage_key())
49    }
50}
thruput_sdk/storage/flags.rs

thruput_sdk/storage/
flags.rs
