camera: Add new RingBufferConsumer to keep a ring buffer of acquired frames

Bug: 8563838
Change-Id: I5a95e0be94e5388b30639905efae42d3c3279f72

2 files changed, 535 insertions, 0 deletions

diff --git a/services/camera/libcameraservice/gui/RingBufferConsumer.cpp b/services/camera/libcameraservice/gui/RingBufferConsumer.cpp
new file mode 100644
index 0000000..1b2a717
--- /dev/null
+++ b/services/camera/libcameraservice/gui/RingBufferConsumer.cpp
@@ -0,0 +1,346 @@
+/*
+ * Copyright (C) 2013 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.
+ */
+
+#undef NDEBUG
+#include <cassert>
+
+//#define LOG_NDEBUG 0
+#define LOG_TAG "RingBufferConsumer"
+#define ATRACE_TAG ATRACE_TAG_GRAPHICS
+#include <utils/Log.h>
+
+#include <gui/RingBufferConsumer.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__)
+
+typedef android::RingBufferConsumer::PinnedBufferItem PinnedBufferItem;
+
+namespace android {
+
+RingBufferConsumer::RingBufferConsumer(uint32_t consumerUsage,
+        int bufferCount) :
+    ConsumerBase(new BufferQueue(true)),
+    mBufferCount(bufferCount)
+{
+    mBufferQueue->setConsumerUsageBits(consumerUsage);
+    mBufferQueue->setSynchronousMode(true);
+    mBufferQueue->setMaxAcquiredBufferCount(bufferCount);
+
+    assert(bufferCount > 0);
+}
+
+RingBufferConsumer::~RingBufferConsumer() {
+}
+
+void RingBufferConsumer::setName(const String8& name) {
+    Mutex::Autolock _l(mMutex);
+    mName = name;
+    mBufferQueue->setConsumerName(name);
+}
+
+sp<PinnedBufferItem> RingBufferConsumer::pinSelectedBuffer(
+        const RingBufferComparator& filter,
+        bool waitForFence) {
+
+    sp<PinnedBufferItem> pinnedBuffer;
+
+    {
+        List<RingBufferItem>::iterator it, end, accIt;
+        BufferInfo acc, cur;
+        BufferInfo* accPtr = NULL;
+
+        Mutex::Autolock _l(mMutex);
+
+        for (it = mBufferItemList.begin(), end = mBufferItemList.end();
+             it != end;
+             ++it) {
+
+            const RingBufferItem& item = *it;
+
+            cur.mCrop = item.mCrop;
+            cur.mTransform = item.mTransform;
+            cur.mScalingMode = item.mScalingMode;
+            cur.mTimestamp = item.mTimestamp;
+            cur.mFrameNumber = item.mFrameNumber;
+            cur.mPinned = item.mPinCount > 0;
+
+            int ret = filter.compare(accPtr, &cur);
+
+            if (ret == 0) {
+                accPtr = NULL;
+            } else if (ret > 0) {
+                acc = cur;
+                accPtr = &acc;
+                accIt = it;
+            } // else acc = acc
+        }
+
+        if (!accPtr) {
+            return NULL;
+        }
+
+        pinnedBuffer = new PinnedBufferItem(this, *accIt);
+        pinBufferLocked(pinnedBuffer->getBufferItem());
+
+    } // end scope of mMutex autolock
+
+    if (pinnedBuffer != 0) {
+        BI_LOGV("Pinned buffer frame %lld, timestamp %lld",
+                pinnedBuffer->getBufferItem().mFrameNumber,
+                pinnedBuffer->getBufferItem().mTimestamp);
+    }
+
+    if (waitForFence) {
+        status_t err = pinnedBuffer->getBufferItem().mFence->waitForever(1000,
+                "RingBufferConsumer::pinSelectedBuffer");
+        if (err != OK) {
+            BI_LOGE("Failed to wait for fence of acquired buffer: %s (%d)",
+                    strerror(-err), err);
+        }
+    }
+
+    return pinnedBuffer;
+}
+
+status_t RingBufferConsumer::clear() {
+
+    status_t err;
+    Mutex::Autolock _l(mMutex);
+
+    BI_LOGV("%s", __FUNCTION__);
+
+    // Avoid annoying log warnings by returning early
+    if (mBufferItemList.size() == 0) {
+        return OK;
+    }
+
+    do {
+        size_t pinnedFrames = 0;
+        err = releaseOldestBufferLocked(&pinnedFrames);
+
+        if (err == NO_BUFFER_AVAILABLE) {
+            assert(pinnedFrames == mBufferItemList.size());
+            break;
+        }
+
+        if (err == NOT_ENOUGH_DATA) {
+            // Fine. Empty buffer item list.
+            break;
+        }
+
+        if (err != OK) {
+            BI_LOGE("Clear failed, could not release buffer");
+            return err;
+        }
+
+    } while(true);
+
+    return OK;
+}
+
+void RingBufferConsumer::pinBufferLocked(const BufferItem& item) {
+    List<RingBufferItem>::iterator it, end;
+
+    for (it = mBufferItemList.begin(), end = mBufferItemList.end();
+         it != end;
+         ++it) {
+
+        RingBufferItem& find = *it;
+        if (item.mGraphicBuffer == find.mGraphicBuffer) {
+            find.mPinCount++;
+            break;
+        }
+    }
+
+    if (it == end) {
+        BI_LOGE("Failed to pin buffer (timestamp %lld, framenumber %lld)",
+                 item.mTimestamp, item.mFrameNumber);
+    }
+}
+
+status_t RingBufferConsumer::releaseOldestBufferLocked(size_t* pinnedFrames) {
+    status_t err = OK;
+
+    List<RingBufferItem>::iterator it, end, accIt;
+
+    it = mBufferItemList.begin();
+    end = mBufferItemList.end();
+    accIt = it;
+
+    if (it == end) {
+        /**
+         * This is fine. We really care about being able to acquire a buffer
+         * successfully after this function completes, not about it releasing
+         * some buffer.
+         */
+        BI_LOGV("%s: No buffers yet acquired, can't release anything",
+              __FUNCTION__);
+        return NOT_ENOUGH_DATA;
+    }
+
+    for (; it != end; ++it) {
+        RingBufferItem& find = *it;
+        if (find.mTimestamp < accIt->mTimestamp && find.mPinCount <= 0) {
+            accIt = it;
+        }
+
+        if (find.mPinCount > 0 && pinnedFrames != NULL) {
+            ++(*pinnedFrames);
+        }
+    }
+
+    if (accIt != end) {
+        RingBufferItem& item = *accIt;
+
+        // In case the object was never pinned, pass the acquire fence
+        // back to the release fence. If the fence was already waited on,
+        // it'll just be a no-op to wait on it again.
+        err = addReleaseFenceLocked(item.mBuf, item.mFence);
+
+        if (err != OK) {
+            BI_LOGE("Failed to add release fence to buffer "
+                    "(timestamp %lld, framenumber %lld",
+                    item.mTimestamp, item.mFrameNumber);
+            return err;
+        }
+
+        BI_LOGV("Attempting to release buffer timestamp %lld, frame %lld",
+                item.mTimestamp, item.mFrameNumber);
+
+        err = releaseBufferLocked(item.mBuf,
+                                  EGL_NO_DISPLAY,
+                                  EGL_NO_SYNC_KHR);
+        if (err != OK) {
+            BI_LOGE("Failed to release buffer: %s (%d)",
+                    strerror(-err), err);
+            return err;
+        }
+
+        BI_LOGV("Buffer timestamp %lld, frame %lld evicted",
+                item.mTimestamp, item.mFrameNumber);
+
+        size_t currentSize = mBufferItemList.size();
+        mBufferItemList.erase(accIt);
+        assert(mBufferItemList.size() == currentSize - 1);
+    } else {
+        BI_LOGW("All buffers pinned, could not find any to release");
+        return NO_BUFFER_AVAILABLE;
+
+    }
+
+    return OK;
+}
+
+void RingBufferConsumer::onFrameAvailable() {
+    status_t err;
+
+    {
+        Mutex::Autolock _l(mMutex);
+
+        /**
+         * Release oldest frame
+         */
+        if (mBufferItemList.size() >= (size_t)mBufferCount) {
+            err = releaseOldestBufferLocked(/*pinnedFrames*/NULL);
+            assert(err != NOT_ENOUGH_DATA);
+
+            // TODO: implement the case for NO_BUFFER_AVAILABLE
+            assert(err != NO_BUFFER_AVAILABLE);
+            if (err != OK) {
+                return;
+            }
+            // TODO: in unpinBuffer rerun this routine if we had buffers
+            // we could've locked but didn't because there was no space
+        }
+
+        RingBufferItem& item = *mBufferItemList.insert(mBufferItemList.end(),
+                                                       RingBufferItem());
+
+        /**
+         * Acquire new frame
+         */
+        err = acquireBufferLocked(&item);
+        if (err != OK) {
+            if (err != NO_BUFFER_AVAILABLE) {
+                BI_LOGE("Error acquiring buffer: %s (%d)", strerror(err), err);
+            }
+
+            mBufferItemList.erase(--mBufferItemList.end());
+            return;
+        }
+
+        BI_LOGV("New buffer acquired (timestamp %lld), "
+                "buffer items %u out of %d",
+                item.mTimestamp,
+                mBufferItemList.size(), mBufferCount);
+
+        item.mGraphicBuffer = mSlots[item.mBuf].mGraphicBuffer;
+    } // end of mMutex lock
+
+    ConsumerBase::onFrameAvailable();
+}
+
+void RingBufferConsumer::unpinBuffer(const BufferItem& item) {
+    Mutex::Autolock _l(mMutex);
+
+    List<RingBufferItem>::iterator it, end, accIt;
+
+    for (it = mBufferItemList.begin(), end = mBufferItemList.end();
+         it != end;
+         ++it) {
+
+        RingBufferItem& find = *it;
+        if (item.mGraphicBuffer == find.mGraphicBuffer) {
+            status_t res = addReleaseFenceLocked(item.mBuf, item.mFence);
+
+            if (res != OK) {
+                BI_LOGE("Failed to add release fence to buffer "
+                        "(timestamp %lld, framenumber %lld",
+                        item.mTimestamp, item.mFrameNumber);
+                return;
+            }
+
+            find.mPinCount--;
+            break;
+        }
+    }
+
+    if (it == end) {
+        BI_LOGE("Failed to unpin buffer (timestamp %lld, framenumber %lld",
+                 item.mTimestamp, item.mFrameNumber);
+    }
+}
+
+status_t RingBufferConsumer::setDefaultBufferSize(uint32_t w, uint32_t h) {
+    Mutex::Autolock _l(mMutex);
+    return mBufferQueue->setDefaultBufferSize(w, h);
+}
+
+status_t RingBufferConsumer::setDefaultBufferFormat(uint32_t defaultFormat) {
+    Mutex::Autolock _l(mMutex);
+    return mBufferQueue->setDefaultBufferFormat(defaultFormat);
+}
+
+status_t RingBufferConsumer::setConsumerUsage(uint32_t usage) {
+    Mutex::Autolock _l(mMutex);
+    return mBufferQueue->setConsumerUsageBits(usage);
+}
+
+} // namespace android
diff --git a/services/camera/libcameraservice/gui/RingBufferConsumer.h b/services/camera/libcameraservice/gui/RingBufferConsumer.h
new file mode 100644
index 0000000..454fbae
--- /dev/null
+++ b/services/camera/libcameraservice/gui/RingBufferConsumer.h
@@ -0,0 +1,189 @@
+/*
+ * Copyright (C) 2013 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_RINGBUFFERCONSUMER_H
+#define ANDROID_GUI_RINGBUFFERCONSUMER_H
+
+#include <gui/ConsumerBase.h>
+
+#include <ui/GraphicBuffer.h>
+
+#include <utils/String8.h>
+#include <utils/Vector.h>
+#include <utils/threads.h>
+#include <utils/List.h>
+
+#define ANDROID_GRAPHICS_RINGBUFFERCONSUMER_JNI_ID "mRingBufferConsumer"
+
+namespace android {
+
+/**
+ * The RingBufferConsumer maintains a ring buffer of BufferItem objects,
+ * (which are 'acquired' as long as they are part of the ring buffer, and
+ *  'released' when they leave the ring buffer).
+ *
+ * When new buffers are produced, the oldest non-pinned buffer item is immediately
+ * dropped from the ring buffer, and overridden with the newest buffer.
+ *
+ * Users can only access a buffer item after pinning it (which also guarantees
+ * that during its duration it will not be released back into the BufferQueue).
+ *
+ * Note that the 'oldest' buffer is the one with the smallest timestamp.
+ *
+ * Edge cases:
+ *  - If ringbuffer is not full, no drops occur when a buffer is produced.
+ *  - If all the buffers get filled or pinned then there will be no empty
+ *    buffers left, so the producer will block on dequeue.
+ */
+class RingBufferConsumer : public ConsumerBase,
+                           public ConsumerBase::FrameAvailableListener
+{
+  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 ring buffer consumer. The consumerUsage parameter determines
+    // the consumer usage flags passed to the graphics allocator. The
+    // bufferCount parameter specifies how many buffers can be pinned for user
+    // access at the same time.
+    RingBufferConsumer(uint32_t consumerUsage,
+            int bufferCount = BufferQueue::MIN_UNDEQUEUED_BUFFERS);
+
+    virtual ~RingBufferConsumer();
+
+    // set the name of the RingBufferConsumer that will be used to identify it in
+    // log messages.
+    void setName(const String8& name);
+
+    sp<IGraphicBufferProducer> getProducerInterface() const { return getBufferQueue(); }
+
+    // setDefaultBufferSize is used to set the size of buffers returned by
+    // requestBuffers when a with and height of zero is requested.
+    status_t setDefaultBufferSize(uint32_t w, uint32_t h);
+
+    // setDefaultBufferFormat allows the BufferQueue to create
+    // GraphicBuffers of a defaultFormat if no format is specified
+    // by the producer endpoint.
+    status_t setDefaultBufferFormat(uint32_t defaultFormat);
+
+    // setConsumerUsage allows the BufferQueue consumer usage to be
+    // set at a later time after construction.
+    status_t setConsumerUsage(uint32_t usage);
+
+    // Buffer info, minus the graphics buffer/slot itself.
+    struct BufferInfo {
+        // mCrop is the current crop rectangle for this buffer slot.
+        Rect mCrop;
+
+        // mTransform is the current transform flags for this buffer slot.
+        uint32_t mTransform;
+
+        // mScalingMode is the current scaling mode for this buffer slot.
+        uint32_t mScalingMode;
+
+        // mTimestamp is the current timestamp for this buffer slot. This gets
+        // to set by queueBuffer each time this slot is queued.
+        int64_t mTimestamp;
+
+        // mFrameNumber is the number of the queued frame for this slot.
+        uint64_t mFrameNumber;
+
+        // mPinned is whether or not the buffer has been pinned already.
+        bool mPinned;
+    };
+
+    struct RingBufferComparator {
+        // Return < 0 to select i1, > 0 to select i2, 0 for neither
+        // i1 or i2 can be NULL.
+        //
+        // The comparator has to implement a total ordering. Otherwise
+        // a linear scan won't find the most preferred buffer.
+        virtual int compare(const BufferInfo* i1,
+                            const BufferInfo* i2) const = 0;
+
+        virtual ~RingBufferComparator() {}
+    };
+
+    struct PinnedBufferItem : public LightRefBase<PinnedBufferItem> {
+        PinnedBufferItem(wp<RingBufferConsumer> consumer,
+                         const BufferItem& item) :
+                mConsumer(consumer),
+                mBufferItem(item) {
+        }
+
+        ~PinnedBufferItem() {
+            sp<RingBufferConsumer> consumer = mConsumer.promote();
+            if (consumer != NULL) {
+                consumer->unpinBuffer(mBufferItem);
+            }
+        }
+
+        bool isEmpty() {
+            return mBufferItem.mBuf == BufferQueue::INVALID_BUFFER_SLOT;
+        }
+
+        BufferItem& getBufferItem() { return mBufferItem; }
+        const BufferItem& getBufferItem() const { return mBufferItem; }
+
+      private:
+        wp<RingBufferConsumer> mConsumer;
+        BufferItem             mBufferItem;
+    };
+
+    // Find a buffer using the filter, then pin it before returning it.
+    //
+    // The filter will be invoked on each buffer item in the ring buffer,
+    // passing the item that was selected from each previous iteration,
+    // as well as the current iteration's item.
+    //
+    // Pinning will ensure that the buffer will not be dropped when a new
+    // frame is available.
+    sp<PinnedBufferItem> pinSelectedBuffer(const RingBufferComparator& filter,
+                                           bool waitForFence = true);
+
+    // Release all the non-pinned buffers in the ring buffer
+    status_t clear();
+
+  private:
+
+    // Override ConsumerBase::onFrameAvailable
+    virtual void onFrameAvailable();
+
+    void pinBufferLocked(const BufferItem& item);
+    void unpinBuffer(const BufferItem& item);
+
+    // Releases oldest buffer. Returns NO_BUFFER_AVAILABLE
+    // if all the buffers were pinned.
+    // Returns NOT_ENOUGH_DATA if list was empty.
+    status_t releaseOldestBufferLocked(size_t* pinnedFrames);
+
+    struct RingBufferItem : public BufferItem {
+        RingBufferItem() : BufferItem(), mPinCount(0) {}
+        int mPinCount;
+    };
+
+    // List of acquired buffers in our ring buffer
+    List<RingBufferItem>       mBufferItemList;
+    const int                  mBufferCount;
+};
+
+} // namespace android
+
+#endif // ANDROID_GUI_CPUCONSUMER_H