Package buildbot :: Module locks :: Class BaseLock

Class BaseLock

Known Subclasses:

RealMasterLock

Class handling claiming and releasing of self, and keeping track of current and waiting owners.

We maintain the wait queue in FIFO order, and ensure that counting waiters in the queue behind exclusive waiters cannot acquire the lock. This ensures that exclusive waiters are not starved.

Instance Methods

__init__(self, name, maxCount=1)

source code

__repr__(self)

source code

isAvailable(self, requester, access)
Return a boolean whether the lock is available for claiming

source code

claim(self, owner, access)
Claim the lock (lock must be available)

source code

subscribeToReleases(self, callback)
Schedule callback to be invoked every time this lock is released. source code

release(self, owner, access)
Release the lock

source code

waitUntilMaybeAvailable(self, owner, access)
Fire when the lock *might* be available.

source code

stopWaitingUntilAvailable(self, owner, access, d)

source code

isOwner(self, owner, access)

source code

Class Variables
	description = `'<BaseLock>'`

Method Details

subscribeToReleases(self, callback)

source code

Schedule callback to be invoked every time this lock is released. Returns a Subscription.

waitUntilMaybeAvailable(self, owner, access)

source code

Fire when the lock *might* be available. The caller will need to check with isAvailable() when the deferred fires. This loose form is used to avoid deadlocks. If we were interested in a stronger form, this would be named 'waitUntilAvailable', and the deferred would fire after the lock had been claimed.