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.

Note: Ideally, we'd like to maintain FIFO order. The place to do that would be the isAvailable() function. However, this function is called by builds/steps both for the first time, and after waking them up by self from the self.waiting queue. There is currently no way of distinguishing between them.

Instance Methods

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__init__(self, name, maxCount=1)

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__repr__(self)

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_getOwnersCount(self)
Return the number of current exclusive and counting owners.

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

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

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release(self, owner, access)
Release the lock

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

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Class Variables

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description = '<BaseLock>'

Method Details

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_getOwnersCount(self)

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Return the number of current exclusive and counting owners.

Returns:: Tuple (number exclusive owners, number counting owners)

waitUntilMaybeAvailable(self, owner, access)

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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.