AIDL bufferpool implementation (just copy from HIDL impl)

Bug: 254050250
Change-Id: I48841189a8743dcd6533a9e61581e48f0f1717f1
diff --git a/media/bufferpool/aidl/default/BufferPoolClient.cpp b/media/bufferpool/aidl/default/BufferPoolClient.cpp
new file mode 100644
index 0000000..cda23ff
--- /dev/null
+++ b/media/bufferpool/aidl/default/BufferPoolClient.cpp
@@ -0,0 +1,876 @@
+/*
+ * Copyright (C) 2018 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_TAG "BufferPoolClient"
+//#define LOG_NDEBUG 0
+
+#include <thread>
+#include <utils/Log.h>
+#include "BufferPoolClient.h"
+#include "Connection.h"
+
+namespace android {
+namespace hardware {
+namespace media {
+namespace bufferpool {
+namespace V2_0 {
+namespace implementation {
+
+static constexpr int64_t kReceiveTimeoutUs = 2000000; // 2s
+static constexpr int kPostMaxRetry = 3;
+static constexpr int kCacheTtlUs = 1000000; // TODO: tune
+static constexpr size_t kMaxCachedBufferCount = 64;
+static constexpr size_t kCachedBufferCountTarget = kMaxCachedBufferCount - 16;
+
+class BufferPoolClient::Impl
+        : public std::enable_shared_from_this<BufferPoolClient::Impl> {
+public:
+    explicit Impl(const sp<Accessor> &accessor, const sp<IObserver> &observer);
+
+    explicit Impl(const sp<IAccessor> &accessor, const sp<IObserver> &observer);
+
+    bool isValid() {
+        return mValid;
+    }
+
+    bool isLocal() {
+        return mValid && mLocal;
+    }
+
+    ConnectionId getConnectionId() {
+        return mConnectionId;
+    }
+
+    sp<IAccessor> &getAccessor() {
+        return mAccessor;
+    }
+
+    bool isActive(int64_t *lastTransactionUs, bool clearCache);
+
+    void receiveInvalidation(uint32_t msgID);
+
+    ResultStatus flush();
+
+    ResultStatus allocate(const std::vector<uint8_t> &params,
+                          native_handle_t **handle,
+                          std::shared_ptr<BufferPoolData> *buffer);
+
+    ResultStatus receive(
+            TransactionId transactionId, BufferId bufferId,
+            int64_t timestampUs,
+            native_handle_t **handle, std::shared_ptr<BufferPoolData> *buffer);
+
+    void postBufferRelease(BufferId bufferId);
+
+    bool postSend(
+            BufferId bufferId, ConnectionId receiver,
+            TransactionId *transactionId, int64_t *timestampUs);
+private:
+
+    bool postReceive(
+            BufferId bufferId, TransactionId transactionId,
+            int64_t timestampUs);
+
+    bool postReceiveResult(
+            BufferId bufferId, TransactionId transactionId, bool result, bool *needsSync);
+
+    void trySyncFromRemote();
+
+    bool syncReleased(uint32_t msgId = 0);
+
+    void evictCaches(bool clearCache = false);
+
+    void invalidateBuffer(BufferId id);
+
+    void invalidateRange(BufferId from, BufferId to);
+
+    ResultStatus allocateBufferHandle(
+            const std::vector<uint8_t>& params, BufferId *bufferId,
+            native_handle_t **handle);
+
+    ResultStatus fetchBufferHandle(
+            TransactionId transactionId, BufferId bufferId,
+            native_handle_t **handle);
+
+    struct BlockPoolDataDtor;
+    struct ClientBuffer;
+
+    bool mLocal;
+    bool mValid;
+    sp<IAccessor> mAccessor;
+    sp<Connection> mLocalConnection;
+    sp<IConnection> mRemoteConnection;
+    uint32_t mSeqId;
+    ConnectionId mConnectionId;
+    int64_t mLastEvictCacheUs;
+    std::unique_ptr<BufferInvalidationListener> mInvalidationListener;
+
+    // CachedBuffers
+    struct BufferCache {
+        std::mutex mLock;
+        bool mCreating;
+        std::condition_variable mCreateCv;
+        std::map<BufferId, std::unique_ptr<ClientBuffer>> mBuffers;
+        int mActive;
+        int64_t mLastChangeUs;
+
+        BufferCache() : mCreating(false), mActive(0), mLastChangeUs(getTimestampNow()) {}
+
+        void incActive_l() {
+            ++mActive;
+            mLastChangeUs = getTimestampNow();
+        }
+
+        void decActive_l() {
+            --mActive;
+            mLastChangeUs = getTimestampNow();
+        }
+
+        int cachedBufferCount() const {
+            return mBuffers.size() - mActive;
+        }
+    } mCache;
+
+    // FMQ - release notifier
+    struct ReleaseCache {
+        std::mutex mLock;
+        // TODO: use only one list?(using one list may dealy sending messages?)
+        std::list<BufferId> mReleasingIds;
+        std::list<BufferId> mReleasedIds;
+        uint32_t mInvalidateId; // TODO: invalidation ACK to bufferpool
+        bool mInvalidateAck;
+        std::unique_ptr<BufferStatusChannel> mStatusChannel;
+
+        ReleaseCache() : mInvalidateId(0), mInvalidateAck(true) {}
+    } mReleasing;
+
+    // This lock is held during synchronization from remote side.
+    // In order to minimize remote calls and locking durtaion, this lock is held
+    // by best effort approach using try_lock().
+    std::mutex mRemoteSyncLock;
+};
+
+struct BufferPoolClient::Impl::BlockPoolDataDtor {
+    BlockPoolDataDtor(const std::shared_ptr<BufferPoolClient::Impl> &impl)
+            : mImpl(impl) {}
+
+    void operator()(BufferPoolData *buffer) {
+        BufferId id = buffer->mId;
+        delete buffer;
+
+        auto impl = mImpl.lock();
+        if (impl && impl->isValid()) {
+            impl->postBufferRelease(id);
+        }
+    }
+    const std::weak_ptr<BufferPoolClient::Impl> mImpl;
+};
+
+struct BufferPoolClient::Impl::ClientBuffer {
+private:
+    int64_t mExpireUs;
+    bool mHasCache;
+    ConnectionId mConnectionId;
+    BufferId mId;
+    native_handle_t *mHandle;
+    std::weak_ptr<BufferPoolData> mCache;
+
+    void updateExpire() {
+        mExpireUs = getTimestampNow() + kCacheTtlUs;
+    }
+
+public:
+    ClientBuffer(
+            ConnectionId connectionId, BufferId id, native_handle_t *handle)
+            : mHasCache(false), mConnectionId(connectionId),
+              mId(id), mHandle(handle) {
+        mExpireUs = getTimestampNow() + kCacheTtlUs;
+    }
+
+    ~ClientBuffer() {
+        if (mHandle) {
+            native_handle_close(mHandle);
+            native_handle_delete(mHandle);
+        }
+    }
+
+    BufferId id() const {
+        return mId;
+    }
+
+    bool expire() const {
+        int64_t now = getTimestampNow();
+        return now >= mExpireUs;
+    }
+
+    bool hasCache() const {
+        return mHasCache;
+    }
+
+    std::shared_ptr<BufferPoolData> fetchCache(native_handle_t **pHandle) {
+        if (mHasCache) {
+            std::shared_ptr<BufferPoolData> cache = mCache.lock();
+            if (cache) {
+                *pHandle = mHandle;
+            }
+            return cache;
+        }
+        return nullptr;
+    }
+
+    std::shared_ptr<BufferPoolData> createCache(
+            const std::shared_ptr<BufferPoolClient::Impl> &impl,
+            native_handle_t **pHandle) {
+        if (!mHasCache) {
+            // Allocates a raw ptr in order to avoid sending #postBufferRelease
+            // from deleter, in case of native_handle_clone failure.
+            BufferPoolData *ptr = new BufferPoolData(mConnectionId, mId);
+            if (ptr) {
+                std::shared_ptr<BufferPoolData> cache(ptr, BlockPoolDataDtor(impl));
+                if (cache) {
+                    mCache = cache;
+                    mHasCache = true;
+                    *pHandle = mHandle;
+                    return cache;
+                }
+            }
+            if (ptr) {
+                delete ptr;
+            }
+        }
+        return nullptr;
+    }
+
+    bool onCacheRelease() {
+        if (mHasCache) {
+            // TODO: verify mCache is not valid;
+            updateExpire();
+            mHasCache = false;
+            return true;
+        }
+        return false;
+    }
+};
+
+BufferPoolClient::Impl::Impl(const sp<Accessor> &accessor, const sp<IObserver> &observer)
+    : mLocal(true), mValid(false), mAccessor(accessor), mSeqId(0),
+      mLastEvictCacheUs(getTimestampNow()) {
+    const StatusDescriptor *statusDesc;
+    const InvalidationDescriptor *invDesc;
+    ResultStatus status = accessor->connect(
+            observer, true,
+            &mLocalConnection, &mConnectionId, &mReleasing.mInvalidateId,
+            &statusDesc, &invDesc);
+    if (status == ResultStatus::OK) {
+        mReleasing.mStatusChannel =
+                std::make_unique<BufferStatusChannel>(*statusDesc);
+        mInvalidationListener =
+                std::make_unique<BufferInvalidationListener>(*invDesc);
+        mValid = mReleasing.mStatusChannel &&
+                mReleasing.mStatusChannel->isValid() &&
+                mInvalidationListener &&
+                mInvalidationListener->isValid();
+    }
+}
+
+BufferPoolClient::Impl::Impl(const sp<IAccessor> &accessor, const sp<IObserver> &observer)
+    : mLocal(false), mValid(false), mAccessor(accessor), mSeqId(0),
+      mLastEvictCacheUs(getTimestampNow()) {
+    bool valid = false;
+    sp<IConnection>& outConnection = mRemoteConnection;
+    ConnectionId& id = mConnectionId;
+    uint32_t& outMsgId = mReleasing.mInvalidateId;
+    std::unique_ptr<BufferStatusChannel>& outChannel =
+            mReleasing.mStatusChannel;
+    std::unique_ptr<BufferInvalidationListener>& outObserver =
+            mInvalidationListener;
+    Return<void> transResult = accessor->connect(
+            observer,
+            [&valid, &outConnection, &id, &outMsgId, &outChannel, &outObserver]
+            (ResultStatus status, sp<IConnection> connection,
+             ConnectionId connectionId, uint32_t msgId,
+             const StatusDescriptor& statusDesc,
+             const InvalidationDescriptor& invDesc) {
+                if (status == ResultStatus::OK) {
+                    outConnection = connection;
+                    id = connectionId;
+                    outMsgId = msgId;
+                    outChannel = std::make_unique<BufferStatusChannel>(statusDesc);
+                    outObserver = std::make_unique<BufferInvalidationListener>(invDesc);
+                    if (outChannel && outChannel->isValid() &&
+                        outObserver && outObserver->isValid()) {
+                        valid = true;
+                    }
+                }
+            });
+    mValid = transResult.isOk() && valid;
+}
+
+bool BufferPoolClient::Impl::isActive(int64_t *lastTransactionUs, bool clearCache) {
+    bool active = false;
+    {
+        std::lock_guard<std::mutex> lock(mCache.mLock);
+        syncReleased();
+        evictCaches(clearCache);
+        *lastTransactionUs = mCache.mLastChangeUs;
+        active = mCache.mActive > 0;
+    }
+    if (mValid && mLocal && mLocalConnection) {
+        mLocalConnection->cleanUp(clearCache);
+        return true;
+    }
+    return active;
+}
+
+void BufferPoolClient::Impl::receiveInvalidation(uint32_t messageId) {
+    std::lock_guard<std::mutex> lock(mCache.mLock);
+    syncReleased(messageId);
+    // TODO: evict cache required?
+}
+
+ResultStatus BufferPoolClient::Impl::flush() {
+    if (!mLocal || !mLocalConnection || !mValid) {
+        return ResultStatus::CRITICAL_ERROR;
+    }
+    {
+        std::unique_lock<std::mutex> lock(mCache.mLock);
+        syncReleased();
+        evictCaches();
+        return mLocalConnection->flush();
+    }
+}
+
+ResultStatus BufferPoolClient::Impl::allocate(
+        const std::vector<uint8_t> &params,
+        native_handle_t **pHandle,
+        std::shared_ptr<BufferPoolData> *buffer) {
+    if (!mLocal || !mLocalConnection || !mValid) {
+        return ResultStatus::CRITICAL_ERROR;
+    }
+    BufferId bufferId;
+    native_handle_t *handle = nullptr;
+    buffer->reset();
+    ResultStatus status = allocateBufferHandle(params, &bufferId, &handle);
+    if (status == ResultStatus::OK) {
+        if (handle) {
+            std::unique_lock<std::mutex> lock(mCache.mLock);
+            syncReleased();
+            evictCaches();
+            auto cacheIt = mCache.mBuffers.find(bufferId);
+            if (cacheIt != mCache.mBuffers.end()) {
+                // TODO: verify it is recycled. (not having active ref)
+                mCache.mBuffers.erase(cacheIt);
+            }
+            auto clientBuffer = std::make_unique<ClientBuffer>(
+                    mConnectionId, bufferId, handle);
+            if (clientBuffer) {
+                auto result = mCache.mBuffers.insert(std::make_pair(
+                        bufferId, std::move(clientBuffer)));
+                if (result.second) {
+                    *buffer = result.first->second->createCache(
+                            shared_from_this(), pHandle);
+                    if (*buffer) {
+                        mCache.incActive_l();
+                    }
+                }
+            }
+        }
+        if (!*buffer) {
+            ALOGV("client cache creation failure %d: %lld",
+                  handle != nullptr, (long long)mConnectionId);
+            status = ResultStatus::NO_MEMORY;
+            postBufferRelease(bufferId);
+        }
+    }
+    return status;
+}
+
+ResultStatus BufferPoolClient::Impl::receive(
+        TransactionId transactionId, BufferId bufferId, int64_t timestampUs,
+        native_handle_t **pHandle,
+        std::shared_ptr<BufferPoolData> *buffer) {
+    if (!mValid) {
+        return ResultStatus::CRITICAL_ERROR;
+    }
+    if (timestampUs != 0) {
+        timestampUs += kReceiveTimeoutUs;
+    }
+    if (!postReceive(bufferId, transactionId, timestampUs)) {
+        return ResultStatus::CRITICAL_ERROR;
+    }
+    ResultStatus status = ResultStatus::CRITICAL_ERROR;
+    buffer->reset();
+    while(1) {
+        std::unique_lock<std::mutex> lock(mCache.mLock);
+        syncReleased();
+        evictCaches();
+        auto cacheIt = mCache.mBuffers.find(bufferId);
+        if (cacheIt != mCache.mBuffers.end()) {
+            if (cacheIt->second->hasCache()) {
+                *buffer = cacheIt->second->fetchCache(pHandle);
+                if (!*buffer) {
+                    // check transfer time_out
+                    lock.unlock();
+                    std::this_thread::yield();
+                    continue;
+                }
+                ALOGV("client receive from reference %lld", (long long)mConnectionId);
+                break;
+            } else {
+                *buffer = cacheIt->second->createCache(shared_from_this(), pHandle);
+                if (*buffer) {
+                    mCache.incActive_l();
+                }
+                ALOGV("client receive from cache %lld", (long long)mConnectionId);
+                break;
+            }
+        } else {
+            if (!mCache.mCreating) {
+                mCache.mCreating = true;
+                lock.unlock();
+                native_handle_t* handle = nullptr;
+                status = fetchBufferHandle(transactionId, bufferId, &handle);
+                lock.lock();
+                if (status == ResultStatus::OK) {
+                    if (handle) {
+                        auto clientBuffer = std::make_unique<ClientBuffer>(
+                                mConnectionId, bufferId, handle);
+                        if (clientBuffer) {
+                            auto result = mCache.mBuffers.insert(
+                                    std::make_pair(bufferId, std::move(
+                                            clientBuffer)));
+                            if (result.second) {
+                                *buffer = result.first->second->createCache(
+                                        shared_from_this(), pHandle);
+                                if (*buffer) {
+                                    mCache.incActive_l();
+                                }
+                            }
+                        }
+                    }
+                    if (!*buffer) {
+                        status = ResultStatus::NO_MEMORY;
+                    }
+                }
+                mCache.mCreating = false;
+                lock.unlock();
+                mCache.mCreateCv.notify_all();
+                break;
+            }
+            mCache.mCreateCv.wait(lock);
+        }
+    }
+    bool needsSync = false;
+    bool posted = postReceiveResult(bufferId, transactionId,
+                                      *buffer ? true : false, &needsSync);
+    ALOGV("client receive %lld - %u : %s (%d)", (long long)mConnectionId, bufferId,
+          *buffer ? "ok" : "fail", posted);
+    if (mValid && mLocal && mLocalConnection) {
+        mLocalConnection->cleanUp(false);
+    }
+    if (needsSync && mRemoteConnection) {
+        trySyncFromRemote();
+    }
+    if (*buffer) {
+        if (!posted) {
+            buffer->reset();
+            return ResultStatus::CRITICAL_ERROR;
+        }
+        return ResultStatus::OK;
+    }
+    return status;
+}
+
+
+void BufferPoolClient::Impl::postBufferRelease(BufferId bufferId) {
+    std::lock_guard<std::mutex> lock(mReleasing.mLock);
+    mReleasing.mReleasingIds.push_back(bufferId);
+    mReleasing.mStatusChannel->postBufferRelease(
+            mConnectionId, mReleasing.mReleasingIds, mReleasing.mReleasedIds);
+}
+
+// TODO: revise ad-hoc posting data structure
+bool BufferPoolClient::Impl::postSend(
+        BufferId bufferId, ConnectionId receiver,
+        TransactionId *transactionId, int64_t *timestampUs) {
+    {
+        // TODO: don't need to call syncReleased every time
+        std::lock_guard<std::mutex> lock(mCache.mLock);
+        syncReleased();
+    }
+    bool ret = false;
+    bool needsSync = false;
+    {
+        std::lock_guard<std::mutex> lock(mReleasing.mLock);
+        *timestampUs = getTimestampNow();
+        *transactionId = (mConnectionId << 32) | mSeqId++;
+        // TODO: retry, add timeout, target?
+        ret =  mReleasing.mStatusChannel->postBufferStatusMessage(
+                *transactionId, bufferId, BufferStatus::TRANSFER_TO, mConnectionId,
+                receiver, mReleasing.mReleasingIds, mReleasing.mReleasedIds);
+        needsSync = !mLocal && mReleasing.mStatusChannel->needsSync();
+    }
+    if (mValid && mLocal && mLocalConnection) {
+        mLocalConnection->cleanUp(false);
+    }
+    if (needsSync && mRemoteConnection) {
+        trySyncFromRemote();
+    }
+    return ret;
+}
+
+bool BufferPoolClient::Impl::postReceive(
+        BufferId bufferId, TransactionId transactionId, int64_t timestampUs) {
+    for (int i = 0; i < kPostMaxRetry; ++i) {
+        std::unique_lock<std::mutex> lock(mReleasing.mLock);
+        int64_t now = getTimestampNow();
+        if (timestampUs == 0 || now < timestampUs) {
+            bool result = mReleasing.mStatusChannel->postBufferStatusMessage(
+                    transactionId, bufferId, BufferStatus::TRANSFER_FROM,
+                    mConnectionId, -1, mReleasing.mReleasingIds,
+                    mReleasing.mReleasedIds);
+            if (result) {
+                return true;
+            }
+            lock.unlock();
+            std::this_thread::yield();
+        } else {
+            mReleasing.mStatusChannel->postBufferStatusMessage(
+                    transactionId, bufferId, BufferStatus::TRANSFER_TIMEOUT,
+                    mConnectionId, -1, mReleasing.mReleasingIds,
+                    mReleasing.mReleasedIds);
+            return false;
+        }
+    }
+    return false;
+}
+
+bool BufferPoolClient::Impl::postReceiveResult(
+        BufferId bufferId, TransactionId transactionId, bool result, bool *needsSync) {
+    std::lock_guard<std::mutex> lock(mReleasing.mLock);
+    // TODO: retry, add timeout
+    bool ret = mReleasing.mStatusChannel->postBufferStatusMessage(
+            transactionId, bufferId,
+            result ? BufferStatus::TRANSFER_OK : BufferStatus::TRANSFER_ERROR,
+            mConnectionId, -1, mReleasing.mReleasingIds,
+            mReleasing.mReleasedIds);
+    *needsSync = !mLocal && mReleasing.mStatusChannel->needsSync();
+    return ret;
+}
+
+void BufferPoolClient::Impl::trySyncFromRemote() {
+    if (mRemoteSyncLock.try_lock()) {
+        bool needsSync = false;
+        {
+            std::lock_guard<std::mutex> lock(mReleasing.mLock);
+            needsSync = mReleasing.mStatusChannel->needsSync();
+        }
+        if (needsSync) {
+            TransactionId transactionId = (mConnectionId << 32);
+            BufferId bufferId = Connection::SYNC_BUFFERID;
+            Return<void> transResult = mRemoteConnection->fetch(
+                    transactionId, bufferId,
+                    []
+                    (ResultStatus outStatus, Buffer outBuffer) {
+                        (void) outStatus;
+                        (void) outBuffer;
+                    });
+            if (!transResult.isOk()) {
+                ALOGD("sync from client %lld failed: bufferpool process died.",
+                      (long long)mConnectionId);
+            }
+        }
+        mRemoteSyncLock.unlock();
+    }
+}
+
+// should have mCache.mLock
+bool BufferPoolClient::Impl::syncReleased(uint32_t messageId) {
+    bool cleared = false;
+    {
+        std::lock_guard<std::mutex> lock(mReleasing.mLock);
+        if (mReleasing.mReleasingIds.size() > 0) {
+            mReleasing.mStatusChannel->postBufferRelease(
+                    mConnectionId, mReleasing.mReleasingIds,
+                    mReleasing.mReleasedIds);
+        }
+        if (mReleasing.mReleasedIds.size() > 0) {
+            for (BufferId& id: mReleasing.mReleasedIds) {
+                ALOGV("client release buffer %lld - %u", (long long)mConnectionId, id);
+                auto found = mCache.mBuffers.find(id);
+                if (found != mCache.mBuffers.end()) {
+                    if (found->second->onCacheRelease()) {
+                        mCache.decActive_l();
+                    } else {
+                        // should not happen!
+                        ALOGW("client %lld cache release status inconsitent!",
+                            (long long)mConnectionId);
+                    }
+                } else {
+                    // should not happen!
+                    ALOGW("client %lld cache status inconsitent!", (long long)mConnectionId);
+                }
+            }
+            mReleasing.mReleasedIds.clear();
+            cleared = true;
+        }
+    }
+    std::vector<BufferInvalidationMessage> invalidations;
+    mInvalidationListener->getInvalidations(invalidations);
+    uint32_t lastMsgId = 0;
+    if (invalidations.size() > 0) {
+        for (auto it = invalidations.begin(); it != invalidations.end(); ++it) {
+            if (it->messageId != 0) {
+                lastMsgId = it->messageId;
+            }
+            if (it->fromBufferId == it->toBufferId) {
+                // TODO: handle fromBufferId = UINT32_MAX
+                invalidateBuffer(it->fromBufferId);
+            } else {
+                invalidateRange(it->fromBufferId, it->toBufferId);
+            }
+        }
+    }
+    {
+        std::lock_guard<std::mutex> lock(mReleasing.mLock);
+        if (lastMsgId != 0) {
+            if (isMessageLater(lastMsgId, mReleasing.mInvalidateId)) {
+                mReleasing.mInvalidateId = lastMsgId;
+                mReleasing.mInvalidateAck = false;
+            }
+        } else if (messageId != 0) {
+            // messages are drained.
+            if (isMessageLater(messageId, mReleasing.mInvalidateId)) {
+                mReleasing.mInvalidateId = messageId;
+                mReleasing.mInvalidateAck = true;
+            }
+        }
+        if (!mReleasing.mInvalidateAck) {
+            // post ACK
+            mReleasing.mStatusChannel->postBufferInvalidateAck(
+                    mConnectionId,
+                    mReleasing.mInvalidateId, &mReleasing.mInvalidateAck);
+            ALOGV("client %lld invalidateion ack (%d) %u",
+                (long long)mConnectionId,
+                mReleasing.mInvalidateAck, mReleasing.mInvalidateId);
+        }
+    }
+    return cleared;
+}
+
+// should have mCache.mLock
+void BufferPoolClient::Impl::evictCaches(bool clearCache) {
+    int64_t now = getTimestampNow();
+    if (now >= mLastEvictCacheUs + kCacheTtlUs ||
+            clearCache || mCache.cachedBufferCount() > kMaxCachedBufferCount) {
+        size_t evicted = 0;
+        for (auto it = mCache.mBuffers.begin(); it != mCache.mBuffers.end();) {
+            if (!it->second->hasCache() && (it->second->expire() ||
+                        clearCache || mCache.cachedBufferCount() > kCachedBufferCountTarget)) {
+                it = mCache.mBuffers.erase(it);
+                ++evicted;
+            } else {
+                ++it;
+            }
+        }
+        ALOGV("cache count %lld : total %zu, active %d, evicted %zu",
+              (long long)mConnectionId, mCache.mBuffers.size(), mCache.mActive, evicted);
+        mLastEvictCacheUs = now;
+    }
+}
+
+// should have mCache.mLock
+void BufferPoolClient::Impl::invalidateBuffer(BufferId id) {
+    for (auto it = mCache.mBuffers.begin(); it != mCache.mBuffers.end(); ++it) {
+        if (id == it->second->id()) {
+            if (!it->second->hasCache()) {
+                mCache.mBuffers.erase(it);
+                ALOGV("cache invalidated %lld : buffer %u",
+                      (long long)mConnectionId, id);
+            } else {
+                ALOGW("Inconsitent invalidation %lld : activer buffer!! %u",
+                      (long long)mConnectionId, (unsigned int)id);
+            }
+            break;
+        }
+    }
+}
+
+// should have mCache.mLock
+void BufferPoolClient::Impl::invalidateRange(BufferId from, BufferId to) {
+    size_t invalidated = 0;
+    for (auto it = mCache.mBuffers.begin(); it != mCache.mBuffers.end();) {
+        if (!it->second->hasCache()) {
+            BufferId bid = it->second->id();
+            if (from < to) {
+                if (from <= bid && bid < to) {
+                    ++invalidated;
+                    it = mCache.mBuffers.erase(it);
+                    continue;
+                }
+            } else {
+                if (from <= bid || bid < to) {
+                    ++invalidated;
+                    it = mCache.mBuffers.erase(it);
+                    continue;
+                }
+            }
+        }
+        ++it;
+    }
+    ALOGV("cache invalidated %lld : # of invalidated %zu",
+          (long long)mConnectionId, invalidated);
+}
+
+ResultStatus BufferPoolClient::Impl::allocateBufferHandle(
+        const std::vector<uint8_t>& params, BufferId *bufferId,
+        native_handle_t** handle) {
+    if (mLocalConnection) {
+        const native_handle_t* allocHandle = nullptr;
+        ResultStatus status = mLocalConnection->allocate(
+                params, bufferId, &allocHandle);
+        if (status == ResultStatus::OK) {
+            *handle = native_handle_clone(allocHandle);
+        }
+        ALOGV("client allocate result %lld %d : %u clone %p",
+              (long long)mConnectionId, status == ResultStatus::OK,
+              *handle ? *bufferId : 0 , *handle);
+        return status;
+    }
+    return ResultStatus::CRITICAL_ERROR;
+}
+
+ResultStatus BufferPoolClient::Impl::fetchBufferHandle(
+        TransactionId transactionId, BufferId bufferId,
+        native_handle_t **handle) {
+    sp<IConnection> connection;
+    if (mLocal) {
+        connection = mLocalConnection;
+    } else {
+        connection = mRemoteConnection;
+    }
+    ResultStatus status;
+    Return<void> transResult = connection->fetch(
+            transactionId, bufferId,
+            [&status, &handle]
+            (ResultStatus outStatus, Buffer outBuffer) {
+                status = outStatus;
+                if (status == ResultStatus::OK) {
+                    *handle = native_handle_clone(
+                            outBuffer.buffer.getNativeHandle());
+                }
+            });
+    return transResult.isOk() ? status : ResultStatus::CRITICAL_ERROR;
+}
+
+
+BufferPoolClient::BufferPoolClient(const sp<Accessor> &accessor,
+                                   const sp<IObserver> &observer) {
+    mImpl = std::make_shared<Impl>(accessor, observer);
+}
+
+BufferPoolClient::BufferPoolClient(const sp<IAccessor> &accessor,
+                                   const sp<IObserver> &observer) {
+    mImpl = std::make_shared<Impl>(accessor, observer);
+}
+
+BufferPoolClient::~BufferPoolClient() {
+    // TODO: how to handle orphaned buffers?
+}
+
+bool BufferPoolClient::isValid() {
+    return mImpl && mImpl->isValid();
+}
+
+bool BufferPoolClient::isLocal() {
+    return mImpl && mImpl->isLocal();
+}
+
+bool BufferPoolClient::isActive(int64_t *lastTransactionUs, bool clearCache) {
+    if (!isValid()) {
+        *lastTransactionUs = 0;
+        return false;
+    }
+    return mImpl->isActive(lastTransactionUs, clearCache);
+}
+
+ConnectionId BufferPoolClient::getConnectionId() {
+    if (isValid()) {
+        return mImpl->getConnectionId();
+    }
+    return -1;
+}
+
+ResultStatus BufferPoolClient::getAccessor(sp<IAccessor> *accessor) {
+    if (isValid()) {
+        *accessor = mImpl->getAccessor();
+        return ResultStatus::OK;
+    }
+    return ResultStatus::CRITICAL_ERROR;
+}
+
+void BufferPoolClient::receiveInvalidation(uint32_t msgId) {
+    ALOGV("bufferpool2 client recv inv %u", msgId);
+    if (isValid()) {
+        mImpl->receiveInvalidation(msgId);
+    }
+}
+
+ResultStatus BufferPoolClient::flush() {
+    if (isValid()) {
+        return mImpl->flush();
+    }
+    return ResultStatus::CRITICAL_ERROR;
+}
+
+ResultStatus BufferPoolClient::allocate(
+        const std::vector<uint8_t> &params,
+        native_handle_t **handle,
+        std::shared_ptr<BufferPoolData> *buffer) {
+    if (isValid()) {
+        return mImpl->allocate(params, handle, buffer);
+    }
+    return ResultStatus::CRITICAL_ERROR;
+}
+
+ResultStatus BufferPoolClient::receive(
+        TransactionId transactionId, BufferId bufferId, int64_t timestampUs,
+        native_handle_t **handle, std::shared_ptr<BufferPoolData> *buffer) {
+    if (isValid()) {
+        return mImpl->receive(transactionId, bufferId, timestampUs, handle, buffer);
+    }
+    return ResultStatus::CRITICAL_ERROR;
+}
+
+ResultStatus BufferPoolClient::postSend(
+        ConnectionId receiverId,
+        const std::shared_ptr<BufferPoolData> &buffer,
+        TransactionId *transactionId,
+        int64_t *timestampUs) {
+    if (isValid()) {
+        bool result = mImpl->postSend(
+                buffer->mId, receiverId, transactionId, timestampUs);
+        return result ? ResultStatus::OK : ResultStatus::CRITICAL_ERROR;
+    }
+    return ResultStatus::CRITICAL_ERROR;
+}
+
+}  // namespace implementation
+}  // namespace V2_0
+}  // namespace bufferpool
+}  // namespace media
+}  // namespace hardware
+}  // namespace android