BQ: Add and expose a unique id

Bug 29422927

Change-Id: I80eab94f073ebc378302f00fa86a740c3643657e
diff --git a/libs/gui/BufferQueueCore.cpp b/libs/gui/BufferQueueCore.cpp
index ba34eb6..569b8f9 100644
--- a/libs/gui/BufferQueueCore.cpp
+++ b/libs/gui/BufferQueueCore.cpp
@@ -44,6 +44,12 @@
             android_atomic_inc(&counter));
 }
 
+static uint64_t getUniqueId() {
+    static std::atomic<uint32_t> counter{0};
+    static uint64_t id = static_cast<uint64_t>(getpid()) << 32;
+    return id | counter++;
+}
+
 BufferQueueCore::BufferQueueCore(const sp<IGraphicBufferAlloc>& allocator) :
     mAllocator(allocator),
     mMutex(),
@@ -82,7 +88,8 @@
     mAutoRefresh(false),
     mSharedBufferSlot(INVALID_BUFFER_SLOT),
     mSharedBufferCache(Rect::INVALID_RECT, 0, NATIVE_WINDOW_SCALING_MODE_FREEZE,
-            HAL_DATASPACE_UNKNOWN)
+            HAL_DATASPACE_UNKNOWN),
+    mUniqueId(getUniqueId())
 {
     if (allocator == NULL) {
         sp<ISurfaceComposer> composer(ComposerService::getComposerService());
diff --git a/libs/gui/BufferQueueProducer.cpp b/libs/gui/BufferQueueProducer.cpp
index be3b6c3..234a863 100644
--- a/libs/gui/BufferQueueProducer.cpp
+++ b/libs/gui/BufferQueueProducer.cpp
@@ -1422,4 +1422,11 @@
     disconnect(api);
 }
 
+status_t BufferQueueProducer::getUniqueId(uint64_t* outId) const {
+    BQ_LOGV("getUniqueId");
+
+    *outId = mCore->mUniqueId;
+    return NO_ERROR;
+}
+
 } // namespace android
diff --git a/libs/gui/IGraphicBufferProducer.cpp b/libs/gui/IGraphicBufferProducer.cpp
index 2c48d83..7d7d09d 100644
--- a/libs/gui/IGraphicBufferProducer.cpp
+++ b/libs/gui/IGraphicBufferProducer.cpp
@@ -55,6 +55,7 @@
     SET_AUTO_REFRESH,
     SET_DEQUEUE_TIMEOUT,
     GET_LAST_QUEUED_BUFFER,
+    GET_UNIQUE_ID,
 };
 
 class BpGraphicBufferProducer : public BpInterface<IGraphicBufferProducer>
@@ -418,6 +419,25 @@
         *outFence = fence;
         return result;
     }
+
+    virtual status_t getUniqueId(uint64_t* outId) const {
+        Parcel data, reply;
+        data.writeInterfaceToken(IGraphicBufferProducer::getInterfaceDescriptor());
+        status_t result = remote()->transact(GET_UNIQUE_ID, data, &reply);
+        if (result != NO_ERROR) {
+            ALOGE("getUniqueId failed to transact: %d", result);
+        }
+        status_t actualResult = NO_ERROR;
+        result = reply.readInt32(&actualResult);
+        if (result != NO_ERROR) {
+            return result;
+        }
+        result = reply.readUint64(outId);
+        if (result != NO_ERROR) {
+            return result;
+        }
+        return actualResult;
+    }
 };
 
 // Out-of-line virtual method definition to trigger vtable emission in this
@@ -659,6 +679,20 @@
             }
             return NO_ERROR;
         }
+        case GET_UNIQUE_ID: {
+            CHECK_INTERFACE(IGraphicBufferProducer, data, reply);
+            uint64_t outId = 0;
+            status_t actualResult = getUniqueId(&outId);
+            status_t result = reply->writeInt32(actualResult);
+            if (result != NO_ERROR) {
+                return result;
+            }
+            result = reply->writeUint64(outId);
+            if (result != NO_ERROR) {
+                return result;
+            }
+            return NO_ERROR;
+        }
     }
     return BBinder::onTransact(code, data, reply, flags);
 }
diff --git a/libs/gui/Surface.cpp b/libs/gui/Surface.cpp
index 9d130cd..bcfe714 100644
--- a/libs/gui/Surface.cpp
+++ b/libs/gui/Surface.cpp
@@ -1279,6 +1279,11 @@
     return mQueueBufferCondition.waitRelative(mMutex, timeout) == OK;
 }
 
+status_t Surface::getUniqueId(uint64_t* outId) const {
+    Mutex::Autolock lock(mMutex);
+    return mGraphicBufferProducer->getUniqueId(outId);
+}
+
 namespace view {
 
 status_t Surface::writeToParcel(Parcel* parcel) const {