commit 021d92e6b92a877b9c8a2d17761be8c2251ad7f6
author Jiwen 'Steve' Cai <jwcai@google.com> Thu Mar 16 21:07:00 2017 -0700
committer Jiwen 'Steve' Cai <jwcai@google.com> Fri Mar 17 15:46:02 2017 -0700
tree 5652a15697cebebf587c1107868b8493353592b7
parent 46f224d19d94324f5e09733c8a16a13a08dd9137

BufferItemConsumer: Add onBufferFreedListener

This callback can reliably notify its listener when a GraphicBuffer is
being freed at the consumer end of a BufferQueue. This is extremely
useful when user of BufferItemConsumer caches the GraphicBuffer, so they
can listen to this callback and clean up resource properly.

Bug: 35114769
Test: Built system, flash marlin (should have no functional change as
the listener is optional).
Change-Id: I591cfd3ece697b1b4fb3efbeff987c7960422d24

libs/gui/BufferItemConsumer.cpp

diff --git a/libs/gui/BufferItemConsumer.cpp b/libs/gui/BufferItemConsumer.cpp
index 3491043..d9d50db 100644
--- a/libs/gui/BufferItemConsumer.cpp
+++ b/libs/gui/BufferItemConsumer.cpp
@@ -22,7 +22,7 @@
 #include <gui/BufferItem.h>
 #include <gui/BufferItemConsumer.h>
 
-//#define BI_LOGV(x, ...) ALOGV("[%s] " x, mName.string(), ##__VA_ARGS__)
+#define BI_LOGV(x, ...) ALOGV("[%s] " x, mName.string(), ##__VA_ARGS__)
 //#define BI_LOGD(x, ...) ALOGD("[%s] " x, mName.string(), ##__VA_ARGS__)
 //#define BI_LOGI(x, ...) ALOGI("[%s] " x, mName.string(), ##__VA_ARGS__)
 //#define BI_LOGW(x, ...) ALOGW("[%s] " x, mName.string(), ##__VA_ARGS__)
@@ -57,6 +57,12 @@
     mConsumer->setConsumerName(name);
 }
 
+void BufferItemConsumer::setBufferFreedListener(
+        const wp<BufferFreedListener>& listener) {
+    Mutex::Autolock _l(mMutex);
+    mBufferFreedListener = listener;
+}
+
 status_t BufferItemConsumer::acquireBuffer(BufferItem *item,
         nsecs_t presentWhen, bool waitForFence) {
     status_t err;
@@ -104,4 +110,14 @@
     return err;
 }
 
+void BufferItemConsumer::freeBufferLocked(int slotIndex) {
+    sp<BufferFreedListener> listener = mBufferFreedListener.promote();
+    if (listener != NULL && mSlots[slotIndex].mGraphicBuffer != NULL) {
+        // Fire callback if we have a listener registered and the buffer being freed is valid.
+        BI_LOGV("actually calling onBufferFreed");
+        listener->onBufferFreed(mSlots[slotIndex].mGraphicBuffer);
+    }
+    ConsumerBase::freeBufferLocked(slotIndex);
+}
+
 } // namespace android