Class: QgsReadWriteLocker¶

The QgsReadWriteLocker class is a convenience class that simplifies locking and unlocking QReadWriteLocks.

Locking and unlocking a QReadWriteLocks in complex functions and statements or in exception handling code is error-prone and difficult to debug. QgsReadWriteLocker can be used in such situations to ensure that the state of the lock is always well-defined.

QgsReadWriteLocker should be created within a function where a QReadWriteLock needs to be locked. The lock may be locked when QgsReadWriteLocker is created or when changeMode is called. You can unlock and relock the lock with unlock() and changeMode(). If locked, the lock will be unlocked when the QgsReadWriteLocker is destroyed.

Added in version 3.4.

Methods

`changeMode`	Change the mode of the lock to mode.
`unlock`	Unlocks the lock.

Attributes

`Read`
`Unlocked`
`Write`

class qgis.core.QgsReadWriteLocker[source]¶

Bases: object

__init__(lock: QReadWriteLock, mode: QgsReadWriteLocker.Mode)

Create a new QgsReadWriteLocker for lock and initialize in mode.

Parameters:

lock (QReadWriteLock)
mode (QgsReadWriteLocker.Mode)

__init__(a0: QgsReadWriteLocker)

Parameters:: a0 (QgsReadWriteLocker)

class Mode¶: Bases: int

Read = 0¶

Unlocked = 2¶

Write = 1¶

changeMode(self, mode: QgsReadWriteLocker.Mode)[source]¶

Change the mode of the lock to mode. The lock will be unlocked and relocked as required.

Parameters:: mode (QgsReadWriteLocker.Mode)

unlock(self)[source]¶: Unlocks the lock. Equivalent to doing changeMode( QgsReadWriteLocker.Unlock );