From d9822a3843017444364899afc3c23fb5be6b9cb9 Mon Sep 17 00:00:00 2001
From: Dan Stoza <stoza@google.com>
Date: Fri, 28 Mar 2014 15:25:31 -0700
Subject: BufferQueueProducer: add detachNextBuffer

Adds a new method, IGBP::detachNextBuffer, that effectively does
dequeue + request + detach in a single call, but does not need to
know anything about the dequeued buffer, and will not block on
dequeue. This is mostly for the upcoming StreamSplitter to use in
its onBufferReleased callback.

Change-Id: Ie88a69de109003acebaa486a5b44c8a455726550
---
 libs/gui/BufferQueueProducer.cpp | 44 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 44 insertions(+)

(limited to 'libs/gui/BufferQueueProducer.cpp')

diff --git a/libs/gui/BufferQueueProducer.cpp b/libs/gui/BufferQueueProducer.cpp
index ea37309fdb..61846dd46a 100644
--- a/libs/gui/BufferQueueProducer.cpp
+++ b/libs/gui/BufferQueueProducer.cpp
@@ -393,6 +393,50 @@ status_t BufferQueueProducer::detachBuffer(int slot) {
     return NO_ERROR;
 }
 
+status_t BufferQueueProducer::detachNextBuffer(sp<GraphicBuffer>* outBuffer,
+        sp<Fence>* outFence) {
+    ATRACE_CALL();
+
+    if (outBuffer == NULL) {
+        BQ_LOGE("detachNextBuffer: outBuffer must not be NULL");
+        return BAD_VALUE;
+    } else if (outFence == NULL) {
+        BQ_LOGE("detachNextBuffer: outFence must not be NULL");
+        return BAD_VALUE;
+    }
+
+    Mutex::Autolock lock(mCore->mMutex);
+
+    if (mCore->mIsAbandoned) {
+        BQ_LOGE("detachNextBuffer: BufferQueue has been abandoned");
+        return NO_INIT;
+    }
+
+    // Find the oldest valid slot
+    int found = BufferQueueCore::INVALID_BUFFER_SLOT;
+    for (int s = 0; s < BufferQueueDefs::NUM_BUFFER_SLOTS; ++s) {
+        if (mSlots[s].mBufferState == BufferSlot::FREE &&
+                mSlots[s].mGraphicBuffer != NULL) {
+            if (found == BufferQueueCore::INVALID_BUFFER_SLOT ||
+                    mSlots[s].mFrameNumber < mSlots[found].mFrameNumber) {
+                found = s;
+            }
+        }
+    }
+
+    if (found == BufferQueueCore::INVALID_BUFFER_SLOT) {
+        return NO_MEMORY;
+    }
+
+    BQ_LOGV("detachNextBuffer detached slot %d", found);
+
+    *outBuffer = mSlots[found].mGraphicBuffer;
+    *outFence = mSlots[found].mFence;
+    mCore->freeBufferLocked(found);
+
+    return NO_ERROR;
+}
+
 status_t BufferQueueProducer::attachBuffer(int* outSlot,
         const sp<android::GraphicBuffer>& buffer) {
     ATRACE_CALL();
-- 
cgit v1.2.3-59-g8ed1b