openpilot v0.6 release

phonelibs/android_frameworks_native/include/gui/BufferQueue.h

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+/*
+ * 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_BUFFERQUEUE_H
+#define ANDROID_GUI_BUFFERQUEUE_H
+
+#include <gui/BufferItem.h>
+#include <gui/BufferQueueDefs.h>
+#include <gui/IGraphicBufferConsumer.h>
+#include <gui/IGraphicBufferProducer.h>
+#include <gui/IConsumerListener.h>
+
+// These are only required to keep other parts of the framework with incomplete
+// dependencies building successfully
+#include <gui/IGraphicBufferAlloc.h>
+
+namespace android {
+
+class BufferQueue {
+public:
+    // BufferQueue will keep track of at most this value of buffers.
+    // Attempts at runtime to increase the number of buffers past this will fail.
+    enum { NUM_BUFFER_SLOTS = BufferQueueDefs::NUM_BUFFER_SLOTS };
+    // Used as a placeholder slot# when the value isn't pointing to an existing buffer.
+    enum { INVALID_BUFFER_SLOT = BufferItem::INVALID_BUFFER_SLOT };
+    // Alias to <IGraphicBufferConsumer.h> -- please scope from there in future code!
+    enum {
+        NO_BUFFER_AVAILABLE = IGraphicBufferConsumer::NO_BUFFER_AVAILABLE,
+        PRESENT_LATER = IGraphicBufferConsumer::PRESENT_LATER,
+    };
+
+    // When in async mode we reserve two slots in order to guarantee that the
+    // producer and consumer can run asynchronously.
+    enum { MAX_MAX_ACQUIRED_BUFFERS = NUM_BUFFER_SLOTS - 2 };
+
+    // for backward source compatibility
+    typedef ::android::ConsumerListener ConsumerListener;
+
+    // ProxyConsumerListener is a ConsumerListener implementation that keeps a weak
+    // reference to the actual consumer object.  It forwards all calls to that
+    // consumer object so long as it exists.
+    //
+    // This class exists to avoid having a circular reference between the
+    // BufferQueue object and the consumer object.  The reason this can't be a weak
+    // reference in the BufferQueue class is because we're planning to expose the
+    // consumer side of a BufferQueue as a binder interface, which doesn't support
+    // weak references.
+    class ProxyConsumerListener : public BnConsumerListener {
+    public:
+        ProxyConsumerListener(const wp<ConsumerListener>& consumerListener);
+        virtual ~ProxyConsumerListener();
+        virtual void onFrameAvailable(const BufferItem& item) override;
+        virtual void onFrameReplaced(const BufferItem& item) override;
+        virtual void onBuffersReleased() override;
+        virtual void onSidebandStreamChanged() override;
+    private:
+        // mConsumerListener is a weak reference to the IConsumerListener.  This is
+        // the raison d'etre of ProxyConsumerListener.
+        wp<ConsumerListener> mConsumerListener;
+    };
+
+    // BufferQueue manages a pool of gralloc memory slots to be used by
+    // producers and consumers. allocator is used to allocate all the
+    // needed gralloc buffers.
+    static void createBufferQueue(sp<IGraphicBufferProducer>* outProducer,
+            sp<IGraphicBufferConsumer>* outConsumer,
+            const sp<IGraphicBufferAlloc>& allocator = NULL);
+
+private:
+    BufferQueue(); // Create through createBufferQueue
+};
+
+// ----------------------------------------------------------------------------
+}; // namespace android
+
+#endif // ANDROID_GUI_BUFFERQUEUE_H