libgui: Add generation numbers to BufferQueue
This change allows producers to set a generation number on a
BufferQueue. This number will be embedded in any new GraphicBuffers
created in that BufferQueue, and attempts to attach buffers which have
a different generation number will fail.
It also plumbs the setGenerationNumber method through Surface, with the
additional effect that any buffers attached to the Surface after
setting a new generation number will automatically be updated with the
new number (as opposed to failing, as would happen on through IGBP).
Bug: 20923096
Change-Id: I32bf726b035f99c3e5834beaf76afb9f01adcbc2
diff --git a/include/gui/IGraphicBufferProducer.h b/include/gui/IGraphicBufferProducer.h
index 5c50b2b..4ca4cd5 100644
--- a/include/gui/IGraphicBufferProducer.h
+++ b/include/gui/IGraphicBufferProducer.h
@@ -218,8 +218,9 @@
//
// Return of a negative value means an error has occurred:
// * NO_INIT - the buffer queue has been abandoned.
- // * BAD_VALUE - outSlot or buffer were NULL or invalid combination of
- // async mode and buffer count override.
+ // * BAD_VALUE - outSlot or buffer were NULL, invalid combination of
+ // async mode and buffer count override, or the generation
+ // number of the buffer did not match the buffer queue.
// * INVALID_OPERATION - cannot attach the buffer because it would cause
// too many buffers to be dequeued, either because
// the producer already has a single buffer dequeued
@@ -470,6 +471,15 @@
// eligible slot is available, dequeueBuffer will block or return an error
// as usual.
virtual status_t allowAllocation(bool allow) = 0;
+
+ // Sets the current generation number of the BufferQueue.
+ //
+ // This generation number will be inserted into any buffers allocated by the
+ // BufferQueue, and any attempts to attach a buffer with a different
+ // generation number will fail. Buffers already in the queue are not
+ // affected and will retain their current generation number. The generation
+ // number defaults to 0.
+ virtual status_t setGenerationNumber(uint32_t generationNumber) = 0;
};
// ----------------------------------------------------------------------------