diff options
| -rw-r--r-- | library/std/src/fs.rs | 57 |
1 files changed, 40 insertions, 17 deletions
diff --git a/library/std/src/fs.rs b/library/std/src/fs.rs index 1f8aac48a9a..a5b0111adfb 100644 --- a/library/std/src/fs.rs +++ b/library/std/src/fs.rs @@ -629,9 +629,9 @@ impl File { /// This acquires an exclusive advisory lock; no other file handle to this file may acquire /// another lock. /// - /// If this file handle, or a clone of it, already holds an advisory lock the exact behavior is - /// unspecified and platform dependent, including the possibility that it will deadlock. - /// However, if this method returns, then an exclusive lock is held. + /// If this file handle/descriptor, or a clone of it, already holds an advisory lock the exact + /// behavior is unspecified and platform dependent, including the possibility that it will + /// deadlock. However, if this method returns, then an exclusive lock is held. /// /// If the file not open for writing, it is unspecified whether this function returns an error. /// @@ -639,6 +639,9 @@ impl File { /// [`try_lock_shared`], and [`unlock`]. Its interactions with other methods, such as [`read`] /// and [`write`] are platform specific, and it may or may not cause non-lockholders to block. /// + /// The lock will be released when this file (along with any other file descriptors/handles + /// duplicated or inherited from it) is closed, or if the [`unlock`] method is called. + /// /// # Platform-specific behavior /// /// This function currently corresponds to the `flock` function on Unix with the `LOCK_EX` flag, @@ -671,19 +674,22 @@ impl File { self.inner.lock() } - /// Acquire a shared advisory lock on the file. Blocks until the lock can be acquired. + /// Acquire a shared (non-exclusive) advisory lock on the file. Blocks until the lock can be acquired. /// /// This acquires a shared advisory lock; more than one file handle may hold a shared lock, but - /// none may hold an exclusive lock. + /// none may hold an exclusive lock at the same time. /// - /// If this file handle, or a clone of it, already holds an advisory lock, the exact behavior is - /// unspecified and platform dependent, including the possibility that it will deadlock. - /// However, if this method returns, then a shared lock is held. + /// If this file handle/descriptor, or a clone of it, already holds an advisory lock, the exact + /// behavior is unspecified and platform dependent, including the possibility that it will + /// deadlock. However, if this method returns, then a shared lock is held. /// /// Note, this is an advisory lock meant to interact with [`lock`], [`try_lock`], /// [`try_lock_shared`], and [`unlock`]. Its interactions with other methods, such as [`read`] /// and [`write`] are platform specific, and it may or may not cause non-lockholders to block. /// + /// The lock will be released when this file (along with any other file descriptors/handles + /// duplicated or inherited from it) is closed, or if the [`unlock`] method is called. + /// /// # Platform-specific behavior /// /// This function currently corresponds to the `flock` function on Unix with the `LOCK_SH` flag, @@ -716,14 +722,18 @@ impl File { self.inner.lock_shared() } - /// Acquire an exclusive advisory lock on the file. Returns `Ok(false)` if the file is locked. + /// Try to acquire an exclusive advisory lock on the file. + /// + /// Returns `Ok(false)` if a different lock is already held on this file (via another + /// handle/descriptor). /// /// This acquires an exclusive advisory lock; no other file handle to this file may acquire /// another lock. /// - /// If this file handle, or a clone of it, already holds an advisory lock, the exact behavior is - /// unspecified and platform dependent, including the possibility that it will deadlock. - /// However, if this method returns, then an exclusive lock is held. + /// If this file handle/descriptor, or a clone of it, already holds an advisory lock, the exact + /// behavior is unspecified and platform dependent, including the possibility that it will + /// deadlock. However, if this method returns `Ok(true)`, then it has acquired an exclusive + /// lock. /// /// If the file not open for writing, it is unspecified whether this function returns an error. /// @@ -731,6 +741,9 @@ impl File { /// [`try_lock_shared`], and [`unlock`]. Its interactions with other methods, such as [`read`] /// and [`write`] are platform specific, and it may or may not cause non-lockholders to block. /// + /// The lock will be released when this file (along with any other file descriptors/handles + /// duplicated or inherited from it) is closed, or if the [`unlock`] method is called. + /// /// # Platform-specific behavior /// /// This function currently corresponds to the `flock` function on Unix with the `LOCK_EX` and @@ -764,20 +777,25 @@ impl File { self.inner.try_lock() } - /// Acquire a shared advisory lock on the file. - /// Returns `Ok(false)` if the file is exclusively locked. + /// Try to acquire a shared (non-exclusive) advisory lock on the file. + /// + /// Returns `Ok(false)` if an exclusive lock is already held on this file (via another + /// handle/descriptor). /// /// This acquires a shared advisory lock; more than one file handle may hold a shared lock, but - /// none may hold an exclusive lock. + /// none may hold an exclusive lock at the same time. /// /// If this file handle, or a clone of it, already holds an advisory lock, the exact behavior is /// unspecified and platform dependent, including the possibility that it will deadlock. - /// However, if this method returns, then a shared lock is held. + /// However, if this method returns `Ok(true)`, then it has acquired a shared lock. /// /// Note, this is an advisory lock meant to interact with [`lock`], [`try_lock`], /// [`try_lock`], and [`unlock`]. Its interactions with other methods, such as [`read`] /// and [`write`] are platform specific, and it may or may not cause non-lockholders to block. /// + /// The lock will be released when this file (along with any other file descriptors/handles + /// duplicated or inherited from it) is closed, or if the [`unlock`] method is called. + /// /// # Platform-specific behavior /// /// This function currently corresponds to the `flock` function on Unix with the `LOCK_SH` and @@ -813,7 +831,12 @@ impl File { /// Release all locks on the file. /// - /// All remaining locks are released when the file handle, and all clones of it, are dropped. + /// All locks are released when the file (along with any other file descriptors/handles + /// duplicated or inherited from it) is closed. This method allows releasing locks without + /// closing the file. + /// + /// If no lock is currently held via this file descriptor/handle, this method may return an + /// error, or may return successfully without taking any action. /// /// # Platform-specific behavior /// |