libgui: Allow an IGBProducer to disable allocation

Adds a new method IGBP::allowAllocation, which controls whether
dequeueBuffer is permitted to allocate a new buffer. If allocation is
disallowed, dequeueBuffer will block or return an error as it
normally would (as controlled by *ControlledByApp).

If there are free buffers, but they are not of the correct dimensions,
format, or usage, they may be freed if a more suitable buffer is not
found first.

Bug: 19801715
Change-Id: I0d604958b78b2fd775c2547690301423f9a52165

1 files changed, 10 insertions, 0 deletions

diff --git a/libs/ui/GraphicBuffer.cpp b/libs/ui/GraphicBuffer.cpp
index 638ac62..d51d514 100644
--- a/libs/ui/GraphicBuffer.cpp
+++ b/libs/ui/GraphicBuffer.cpp
@@ -152,6 +152,16 @@ status_t GraphicBuffer::reallocate(uint32_t inWidth, uint32_t inHeight,
     return initSize(inWidth, inHeight, inFormat, inUsage);
 }
 
+bool GraphicBuffer::needsReallocation(uint32_t inWidth, uint32_t inHeight,
+        PixelFormat inFormat, uint32_t inUsage)
+{
+    if (static_cast<int>(inWidth) != width) return true;
+    if (static_cast<int>(inHeight) != height) return true;
+    if (inFormat != format) return true;
+    if ((static_cast<uint32_t>(usage) & inUsage) != inUsage) return true;
+    return false;
+}
+
 status_t GraphicBuffer::initSize(uint32_t inWidth, uint32_t inHeight,
         PixelFormat inFormat, uint32_t inUsage)
 {