Add BufferItemConsumer, a simple BufferQueue consumer.

BufferItemConsumer allows for acquiring BufferQueue's BufferItems,
which contain all the data and metadata the BufferQueue has for a
given graphics buffer.

This consumer is useful when direct access to the native buffer_handles
is needed by the client.

Also includes a minor cleanup of CpuConsumer's use of 'virtual'.

Bug: 6243944
Change-Id: If7dc4192b15ac499555f1eda42a85140f2434795

include/gui/BufferItemConsumer.h

@@ -0,0 +1,91 @@
+/*
+ * Copyright (C) 2012 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef ANDROID_GUI_BUFFERITEMCONSUMER_H
+#define ANDROID_GUI_BUFFERITEMCONSUMER_H
+
+#include <gui/ConsumerBase.h>
+
+#include <ui/GraphicBuffer.h>
+
+#include <utils/String8.h>
+#include <utils/Vector.h>
+#include <utils/threads.h>
+
+#define ANDROID_GRAPHICS_BUFFERITEMCONSUMER_JNI_ID "mBufferItemConsumer"
+
+namespace android {
+
+/**
+ * BufferItemConsumer is a BufferQueue consumer endpoint that allows clients
+ * access to the whole BufferItem entry from BufferQueue. Multiple buffers may
+ * be acquired at once, to be used concurrently by the client. This consumer can
+ * operate either in synchronous or asynchronous mode.
+ */
+class BufferItemConsumer: public ConsumerBase
+{
+  public:
+    typedef ConsumerBase::FrameAvailableListener FrameAvailableListener;
+
+    typedef BufferQueue::BufferItem BufferItem;
+
+    enum { INVALID_BUFFER_SLOT = BufferQueue::INVALID_BUFFER_SLOT };
+    enum { NO_BUFFER_AVAILABLE = BufferQueue::NO_BUFFER_AVAILABLE };
+
+    // Create a new buffer item consumer. The consumerUsage parameter determines
+    // the consumer usage flags passed to the graphics allocator. The
+    // bufferCount parameter specifies how many buffers can be locked for user
+    // access at the same time.
+    BufferItemConsumer(uint32_t consumerUsage,
+            int bufferCount = BufferQueue::MIN_UNDEQUEUED_BUFFERS,
+            bool synchronousMode = false);
+
+    virtual ~BufferItemConsumer();
+
+    // set the name of the BufferItemConsumer that will be used to identify it in
+    // log messages.
+    void setName(const String8& name);
+
+    // Gets the next graphics buffer from the producer, filling out the
+    // passed-in BufferItem structure. Returns NO_BUFFER_AVAILABLE if the queue
+    // of buffers is empty, and INVALID_OPERATION if the maximum number of
+    // buffers is already acquired.
+    //
+    // Only a fixed number of buffers can be acquired at a time, determined by
+    // the construction-time bufferCount parameter. If INVALID_OPERATION is
+    // returned by acquireBuffer, then old buffers must be returned to the
+    // queue by calling releaseBuffer before more buffers can be acquired.
+    //
+    // If waitForFence is true, and the acquired BufferItem has a valid fence object,
+    // acquireBuffer will wait on the fence with no timeout before returning.
+    status_t acquireBuffer(BufferItem *item, bool waitForFence = true);
+
+    // Returns an acquired buffer to the queue, allowing it to be reused. Since
+    // only a fixed number of buffers may be acquired at a time, old buffers
+    // must be released by calling releaseBuffer to ensure new buffers can be
+    // acquired by acquireBuffer. Once a BufferItem is released, the caller must
+    // not access any members of the BufferItem, and should immediately remove
+    // all of its references to the BufferItem itself.
+    status_t releaseBuffer(const BufferItem &item,
+            const sp<Fence>& releaseFence = Fence::NO_FENCE);
+
+    sp<ISurfaceTexture> getProducerInterface() const { return getBufferQueue(); }
+
+};
+
+} // namespace android
+
+#endif // ANDROID_GUI_CPUCONSUMER_H

include/gui/CpuConsumer.h

@@ -59,6 +59,8 @@ class CpuConsumer: public ConsumerBase
     // how many buffers can be locked for user access at the same time.
     CpuConsumer(uint32_t maxLockedBuffers);
 
+    virtual ~CpuConsumer();
+
     // set the name of the CpuConsumer that will be used to identify it in
     // log messages.
     void setName(const String8& name);
@@ -86,7 +88,7 @@ class CpuConsumer: public ConsumerBase
     // Maximum number of buffers that can be locked at a time
     uint32_t mMaxLockedBuffers;
 
-    void freeBufferLocked(int slotIndex);
+    virtual void freeBufferLocked(int slotIndex);
 
     // Array for tracking pointers passed to the consumer, matching the
     // mSlots indexing

libs/gui/Android.mk

@@ -23,7 +23,8 @@ LOCAL_SRC_FILES:= \
 	Surface.cpp \
 	SurfaceComposerClient.cpp \
 	DummyConsumer.cpp \
-	CpuConsumer.cpp
+	CpuConsumer.cpp \
+	BufferItemConsumer.cpp
 
 LOCAL_SHARED_LIBRARIES := \
 	libbinder \

libs/gui/BufferItemConsumer.cpp

@@ -0,0 +1,93 @@
+/*
+ * Copyright (C) 2012 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+//#define LOG_NDEBUG 0
+#define LOG_TAG "BufferItemConsumer"
+#define ATRACE_TAG ATRACE_TAG_GRAPHICS
+#include <utils/Log.h>
+
+#include <gui/BufferItemConsumer.h>
+
+#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__)
+#define BI_LOGE(x, ...) ALOGE("[%s] "x, mName.string(), ##__VA_ARGS__)
+
+namespace android {
+
+BufferItemConsumer::BufferItemConsumer(uint32_t consumerUsage,
+        int bufferCount, bool synchronousMode) :
+    ConsumerBase(new BufferQueue(true, bufferCount) )
+{
+    mBufferQueue->setConsumerUsageBits(consumerUsage);
+    mBufferQueue->setSynchronousMode(synchronousMode);
+}
+
+BufferItemConsumer::~BufferItemConsumer() {
+}
+
+void BufferItemConsumer::setName(const String8& name) {
+    Mutex::Autolock _l(mMutex);
+    mName = name;
+    mBufferQueue->setConsumerName(name);
+}
+
+status_t BufferItemConsumer::acquireBuffer(BufferItem *item, bool waitForFence) {
+    status_t err;
+
+    if (!item) return BAD_VALUE;
+
+    Mutex::Autolock _l(mMutex);
+
+    err = acquireBufferLocked(item);
+    if (err != OK) {
+        if (err != NO_BUFFER_AVAILABLE) {
+            BI_LOGE("Error acquiring buffer: %s (%d)", strerror(err), err);
+        }
+        return err;
+    }
+
+    if (waitForFence && item->mFence.get()) {
+        err = item->mFence->wait(Fence::TIMEOUT_NEVER);
+        if (err != OK) {
+            BI_LOGE("Failed to wait for fence of acquired buffer: %s (%d)",
+                    strerror(-err), err);
+            return err;
+        }
+    }
+
+    item->mGraphicBuffer = mSlots[item->mBuf].mGraphicBuffer;
+
+    return OK;
+}
+
+status_t BufferItemConsumer::releaseBuffer(const BufferItem &item,
+        const sp<Fence>& releaseFence) {
+    status_t err;
+
+    Mutex::Autolock _l(mMutex);
+
+    err = releaseBufferLocked(item.mBuf, EGL_NO_DISPLAY,
+            EGL_NO_SYNC_KHR, releaseFence);
+    if (err != OK) {
+        BI_LOGE("Failed to release buffer: %s (%d)",
+                strerror(-err), err);
+    }
+    return err;
+}
+
+} // namespace android

libs/gui/CpuConsumer.cpp

@@ -43,6 +43,9 @@ CpuConsumer::CpuConsumer(uint32_t maxLockedBuffers) :
     mBufferQueue->setConsumerUsageBits(GRALLOC_USAGE_SW_READ_OFTEN);
 }
 
+CpuConsumer::~CpuConsumer() {
+}
+
 void CpuConsumer::setName(const String8& name) {
     Mutex::Autolock _l(mMutex);
     mName = name;