commit 7ef724dc97eb2fb997a5ecb4f6991f07971015d4
author Hans Boehm <hboehm@google.com> Fri Aug 17 20:37:19 2018 +0000
committer Gerrit Code Review <noreply-gerritcodereview@google.com> Fri Aug 17 20:37:19 2018 +0000
tree a1151b93541596f532482c850dad6db1be9150b1
parent 71a2d52f19d868751413e7664f208757b9214907
parent a1b4d0fdb906935d411b7fd363f7ee261c5aa995

Merge "Initialize mMetaData correctly, fix ref count"

media/libmediaextractor/MediaBuffer.cpp

diff --git a/media/libmediaextractor/MediaBuffer.cpp b/media/libmediaextractor/MediaBuffer.cpp
index 39f8d6e..d197b3f 100644
--- a/media/libmediaextractor/MediaBuffer.cpp
+++ b/media/libmediaextractor/MediaBuffer.cpp
@@ -39,7 +39,7 @@
       mRangeOffset(0),
       mRangeLength(size),
       mOwnsData(false),
-      mMetaData(new MetaData),
+      mMetaData(new MetaDataBase),
       mOriginal(NULL) {
 }
 
@@ -51,7 +51,7 @@
       mRangeOffset(0),
       mRangeLength(size),
       mOwnsData(true),
-      mMetaData(new MetaData),
+      mMetaData(new MetaDataBase),
       mOriginal(NULL) {
     if (size < kSharedMemThreshold
             || std::atomic_load_explicit(&mUseSharedMemory, std::memory_order_seq_cst) == 0) {
@@ -84,7 +84,7 @@
       mRangeLength(mSize),
       mBuffer(buffer),
       mOwnsData(false),
-      mMetaData(new MetaData),
+      mMetaData(new MetaDataBase),
       mOriginal(NULL) {
 }
 
@@ -96,7 +96,7 @@
         return;
     }
 
-    int prevCount = __sync_fetch_and_sub(&mRefCount, 1);
+    int prevCount = mRefCount.fetch_sub(1);
     if (prevCount == 1) {
         if (mObserver == NULL) {
             delete this;
@@ -110,13 +110,13 @@
 
 void MediaBuffer::claim() {
     CHECK(mObserver != NULL);
-    CHECK_EQ(mRefCount, 1);
+    CHECK_EQ(mRefCount.load(std::memory_order_relaxed), 1);
 
-    mRefCount = 0;
+    mRefCount.store(0, std::memory_order_relaxed);
 }
 
 void MediaBuffer::add_ref() {
-    (void) __sync_fetch_and_add(&mRefCount, 1);
+    (void) mRefCount.fetch_add(1);
 }
 
 void *MediaBuffer::data() const {

media/libmediaextractor/include/media/stagefright/MediaBuffer.h

diff --git a/media/libmediaextractor/include/media/stagefright/MediaBuffer.h b/media/libmediaextractor/include/media/stagefright/MediaBuffer.h
index f944d51..5a25965 100644
--- a/media/libmediaextractor/include/media/stagefright/MediaBuffer.h
+++ b/media/libmediaextractor/include/media/stagefright/MediaBuffer.h
@@ -86,12 +86,14 @@
     virtual MediaBufferBase *clone();
 
     // sum of localRefcount() and remoteRefcount()
+    // Result should be treated as approximate unless the result precludes concurrent accesses.
     virtual int refcount() const {
         return localRefcount() + remoteRefcount();
     }
 
+    // Result should be treated as approximate unless the result precludes concurrent accesses.
     virtual int localRefcount() const {
-        return mRefCount;
+        return mRefCount.load(std::memory_order_relaxed);
     }
 
     virtual int remoteRefcount() const {
@@ -146,7 +148,7 @@
     void claim();
 
     MediaBufferObserver *mObserver;
-    int mRefCount;
+    std::atomic<int> mRefCount;
 
     void *mData;
     size_t mSize, mRangeOffset, mRangeLength;