Provide a basic BLASTBufferQueue implementation.

Provide a utility class which hooks the consumer end of
a BufferQueue up to BLAST. This is a trivial implementation
to enable experimentation in the client framework to begin.

Bug: 135786080
Test: Accompanying frameworks/base changes
Change-Id: I7400dc421d264a00d14e0a928c060b94bc5e5dfc
diff --git a/libs/gui/BLASTBufferQueue.cpp b/libs/gui/BLASTBufferQueue.cpp
new file mode 100644
index 0000000..3a369cd
--- /dev/null
+++ b/libs/gui/BLASTBufferQueue.cpp
@@ -0,0 +1,126 @@
+/*
+ * Copyright (C) 2019 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.
+ */
+
+#include <gui/BLASTBufferQueue.h>
+#include <gui/BufferItemConsumer.h>
+
+#include <chrono>
+
+using namespace std::chrono_literals;
+
+namespace android {
+
+BLASTBufferQueue::BLASTBufferQueue(const sp<SurfaceControl>& surface, int width, int height)
+      : mSurfaceControl(surface), mWidth(width), mHeight(height) {
+    BufferQueue::createBufferQueue(&mProducer, &mConsumer);
+    mBufferItemConsumer =
+            new BufferItemConsumer(mConsumer, AHARDWAREBUFFER_USAGE_GPU_FRAMEBUFFER, 1, true);
+    mBufferItemConsumer->setName(String8("BLAST Consumer"));
+    mBufferItemConsumer->setFrameAvailableListener(this);
+    mBufferItemConsumer->setBufferFreedListener(this);
+    mBufferItemConsumer->setDefaultBufferSize(mWidth, mHeight);
+    mBufferItemConsumer->setDefaultBufferFormat(PIXEL_FORMAT_RGBA_8888);
+}
+
+void BLASTBufferQueue::update(const sp<SurfaceControl>& surface, int width, int height) {
+    std::unique_lock _lock{mMutex};
+    mSurfaceControl = surface;
+    mWidth = width;
+    mHeight = height;
+    mBufferItemConsumer->setDefaultBufferSize(mWidth, mHeight);
+}
+
+static void transactionCallbackThunk(void* context, nsecs_t latchTime,
+                                     const sp<Fence>& presentFence,
+                                     const std::vector<SurfaceControlStats>& stats) {
+    if (context == nullptr) {
+        return;
+    }
+    BLASTBufferQueue* bq = static_cast<BLASTBufferQueue*>(context);
+    bq->transactionCallback(latchTime, presentFence, stats);
+}
+
+void BLASTBufferQueue::transactionCallback(nsecs_t /*latchTime*/, const sp<Fence>& /*presentFence*/,
+                                           const std::vector<SurfaceControlStats>& stats) {
+    std::unique_lock _lock{mMutex};
+
+    if (stats.size() > 0 && mNextCallbackBufferItem.mGraphicBuffer != nullptr) {
+        mBufferItemConsumer->releaseBuffer(mNextCallbackBufferItem,
+                                           stats[0].previousReleaseFence
+                                                   ? stats[0].previousReleaseFence
+                                                   : Fence::NO_FENCE);
+        mNextCallbackBufferItem = BufferItem();
+    }
+    mDequeueWaitCV.notify_one();
+    decStrong((void*)transactionCallbackThunk);
+}
+
+void BLASTBufferQueue::onFrameAvailable(const BufferItem& item) {
+    std::unique_lock _lock{mMutex};
+
+    SurfaceComposerClient::Transaction localTransaction;
+    bool applyTransaction = true;
+    SurfaceComposerClient::Transaction* t = &localTransaction;
+    if (mNextTransaction != nullptr) {
+        t = mNextTransaction;
+        mNextTransaction = nullptr;
+        applyTransaction = false;
+    }
+
+    int status = OK;
+    mNextCallbackBufferItem = mLastSubmittedBufferItem;
+
+    mLastSubmittedBufferItem = BufferItem();
+    status = mBufferItemConsumer->acquireBuffer(&mLastSubmittedBufferItem, -1, false);
+    if (status != OK) {
+        ALOGE("Failed to acquire?");
+    }
+
+    auto buffer = mLastSubmittedBufferItem.mGraphicBuffer;
+
+    if (buffer == nullptr) {
+        ALOGE("Null buffer");
+        return;
+    }
+
+
+    // Ensure BLASTBufferQueue stays alive until we receive the transaction complete callback.
+    incStrong((void*)transactionCallbackThunk);
+
+    t->setBuffer(mSurfaceControl, buffer);
+    t->setAcquireFence(mSurfaceControl,
+                       item.mFence ? new Fence(item.mFence->dup()) : Fence::NO_FENCE);
+    t->addTransactionCompletedCallback(transactionCallbackThunk, static_cast<void*>(this));
+
+    t->setFrame(mSurfaceControl, {0, 0, (int32_t)buffer->getWidth(), (int32_t)buffer->getHeight()});
+    t->setCrop(mSurfaceControl, {0, 0, (int32_t)buffer->getWidth(), (int32_t)buffer->getHeight()});
+
+    if (applyTransaction) {
+        ALOGE("Apply transaction");
+        t->apply();
+
+        if (mNextCallbackBufferItem.mGraphicBuffer != nullptr) {
+            mDequeueWaitCV.wait_for(_lock, 5000ms);
+        }
+    }
+}
+
+void BLASTBufferQueue::setNextTransaction(SurfaceComposerClient::Transaction* t) {
+    std::unique_lock _lock{mMutex};
+    mNextTransaction = t;
+}
+
+} // namespace android