Add a BufferQueue CPU consumer.

Aimed for use cases where gralloc buffers need to be consumed by CPU
users, such as camera image data streams.

The CpuConsumer is a synchronous queue, which exposes raw pointers to
the underlying graphics buffers to applications. Multiple buffers may
be acquired at once, up to the limit set at time of construction.

Change-Id: If1d99f12471438e95a69696e40685948778055fd
diff --git a/libs/gui/CpuConsumer.cpp b/libs/gui/CpuConsumer.cpp
new file mode 100644
index 0000000..48a54c7
--- /dev/null
+++ b/libs/gui/CpuConsumer.cpp
@@ -0,0 +1,231 @@
+/*
+ * 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 "CpuConsumer"
+#define ATRACE_TAG ATRACE_TAG_GRAPHICS
+#include <utils/Log.h>
+
+#include <gui/CpuConsumer.h>
+
+#define CC_LOGV(x, ...) ALOGV("[%s] "x, mName.string(), ##__VA_ARGS__)
+#define CC_LOGD(x, ...) ALOGD("[%s] "x, mName.string(), ##__VA_ARGS__)
+#define CC_LOGI(x, ...) ALOGI("[%s] "x, mName.string(), ##__VA_ARGS__)
+#define CC_LOGW(x, ...) ALOGW("[%s] "x, mName.string(), ##__VA_ARGS__)
+#define CC_LOGE(x, ...) ALOGE("[%s] "x, mName.string(), ##__VA_ARGS__)
+
+namespace android {
+
+// Get an ID that's unique within this process.
+static int32_t createProcessUniqueId() {
+    static volatile int32_t globalCounter = 0;
+    return android_atomic_inc(&globalCounter);
+}
+
+CpuConsumer::CpuConsumer(uint32_t maxLockedBuffers) :
+    mMaxLockedBuffers(maxLockedBuffers),
+    mCurrentLockedBuffers(0)
+{
+    mName = String8::format("cc-unnamed-%d-%d", getpid(),
+            createProcessUniqueId());
+
+    for (int i = 0; i < BufferQueue::NUM_BUFFER_SLOTS; i++) {
+        mBufferPointers[i] = NULL;
+    }
+
+    mBufferQueue = new BufferQueue(true);
+
+    wp<BufferQueue::ConsumerListener> listener;
+    sp<BufferQueue::ConsumerListener> proxy;
+    listener = static_cast<BufferQueue::ConsumerListener*>(this);
+    proxy = new BufferQueue::ProxyConsumerListener(listener);
+
+    status_t err = mBufferQueue->consumerConnect(proxy);
+    if (err != NO_ERROR) {
+        ALOGE("CpuConsumer: error connecting to BufferQueue: %s (%d)",
+                strerror(-err), err);
+    } else {
+        mBufferQueue->setSynchronousMode(true);
+        mBufferQueue->setConsumerUsageBits(GRALLOC_USAGE_SW_READ_OFTEN);
+        mBufferQueue->setConsumerName(mName);
+    }
+}
+
+CpuConsumer::~CpuConsumer()
+{
+    Mutex::Autolock _l(mMutex);
+    for (int i = 0; i < BufferQueue::NUM_BUFFER_SLOTS; i++) {
+        freeBufferLocked(i);
+    }
+    mBufferQueue->consumerDisconnect();
+    mBufferQueue.clear();
+}
+
+void CpuConsumer::setName(const String8& name) {
+    Mutex::Autolock _l(mMutex);
+    mName = name;
+    mBufferQueue->setConsumerName(name);
+}
+
+status_t CpuConsumer::lockNextBuffer(LockedBuffer *nativeBuffer) {
+    status_t err;
+
+    if (!nativeBuffer) return BAD_VALUE;
+    if (mCurrentLockedBuffers == mMaxLockedBuffers) {
+        return INVALID_OPERATION;
+    }
+
+    BufferQueue::BufferItem b;
+
+    Mutex::Autolock _l(mMutex);
+
+    err = mBufferQueue->acquireBuffer(&b);
+    if (err != OK) {
+        if (err == BufferQueue::NO_BUFFER_AVAILABLE) {
+            return BAD_VALUE;
+        } else {
+            CC_LOGE("Error acquiring buffer: %s (%d)", strerror(err), err);
+            return err;
+        }
+    }
+
+    int buf = b.mBuf;
+
+    if (b.mGraphicBuffer != NULL) {
+        if (mBufferPointers[buf] != NULL) {
+            CC_LOGE("Reallocation of buffer %d while in consumer use!", buf);
+            mBufferQueue->releaseBuffer(buf, EGL_NO_DISPLAY, EGL_NO_SYNC_KHR);
+            return BAD_VALUE;
+        }
+        mBufferSlot[buf] = b.mGraphicBuffer;
+    }
+
+    err = mBufferSlot[buf]->lock(
+        GraphicBuffer::USAGE_SW_READ_OFTEN,
+        b.mCrop,
+        &mBufferPointers[buf]);
+
+    if (mBufferPointers[buf] != NULL && err != OK) {
+        CC_LOGE("Unable to lock buffer for CPU reading: %s (%d)", strerror(-err),
+                err);
+        return err;
+    }
+
+    nativeBuffer->data   = reinterpret_cast<uint8_t*>(mBufferPointers[buf]);
+    nativeBuffer->width  = mBufferSlot[buf]->getWidth();
+    nativeBuffer->height = mBufferSlot[buf]->getHeight();
+    nativeBuffer->format = mBufferSlot[buf]->getPixelFormat();
+    nativeBuffer->stride = mBufferSlot[buf]->getStride();
+
+    nativeBuffer->crop        = b.mCrop;
+    nativeBuffer->transform   = b.mTransform;
+    nativeBuffer->scalingMode = b.mScalingMode;
+    nativeBuffer->timestamp   = b.mTimestamp;
+    nativeBuffer->frameNumber = b.mFrameNumber;
+
+    mCurrentLockedBuffers++;
+
+    return OK;
+}
+
+status_t CpuConsumer::unlockBuffer(const LockedBuffer &nativeBuffer) {
+    Mutex::Autolock _l(mMutex);
+    int buf = 0;
+    status_t err;
+
+    void *bufPtr = reinterpret_cast<void *>(nativeBuffer.data);
+    for (; buf < BufferQueue::NUM_BUFFER_SLOTS; buf++) {
+        if (bufPtr == mBufferPointers[buf]) break;
+    }
+    if (buf == BufferQueue::NUM_BUFFER_SLOTS) {
+        CC_LOGE("%s: Can't find buffer to free", __FUNCTION__);
+        return BAD_VALUE;
+    }
+
+    mBufferPointers[buf] = NULL;
+    err = mBufferSlot[buf]->unlock();
+    if (err != OK) {
+        CC_LOGE("%s: Unable to unlock graphic buffer %d", __FUNCTION__, buf);
+        return err;
+    }
+    err = mBufferQueue->releaseBuffer(buf, EGL_NO_DISPLAY, EGL_NO_SYNC_KHR);
+    if (err == BufferQueue::STALE_BUFFER_SLOT) {
+        freeBufferLocked(buf);
+    } else if (err != OK) {
+        CC_LOGE("%s: Unable to release graphic buffer %d to queue", __FUNCTION__,
+                buf);
+        return err;
+    }
+
+    mCurrentLockedBuffers--;
+
+    return OK;
+}
+
+void CpuConsumer::setFrameAvailableListener(
+        const sp<FrameAvailableListener>& listener) {
+    CC_LOGV("setFrameAvailableListener");
+    Mutex::Autolock lock(mMutex);
+    mFrameAvailableListener = listener;
+}
+
+
+void CpuConsumer::onFrameAvailable() {
+    CC_LOGV("onFrameAvailable");
+    sp<FrameAvailableListener> listener;
+    { // scope for the lock
+        Mutex::Autolock _l(mMutex);
+        listener = mFrameAvailableListener;
+    }
+
+    if (listener != NULL) {
+        CC_LOGV("actually calling onFrameAvailable");
+        listener->onFrameAvailable();
+    }
+}
+
+void CpuConsumer::onBuffersReleased() {
+    CC_LOGV("onBuffersReleased");
+
+    Mutex::Autolock lock(mMutex);
+
+    uint32_t mask = 0;
+    mBufferQueue->getReleasedBuffers(&mask);
+    for (int i = 0; i < BufferQueue::NUM_BUFFER_SLOTS; i++) {
+        if (mask & (1 << i)) {
+            freeBufferLocked(i);
+        }
+    }
+
+}
+
+status_t CpuConsumer::freeBufferLocked(int buf) {
+    status_t err = OK;
+
+    if (mBufferPointers[buf] != NULL) {
+        CC_LOGW("Buffer %d freed while locked by consumer", buf);
+        mBufferPointers[buf] = NULL;
+        err = mBufferSlot[buf]->unlock();
+        if (err != OK) {
+            CC_LOGE("%s: Unable to unlock graphic buffer %d", __FUNCTION__, buf);
+        }
+        mCurrentLockedBuffers--;
+    }
+    mBufferSlot[buf] = NULL;
+    return err;
+}
+
+} // namespace android