bufferpool2.0: Implement buffer invalidation

Change-Id: If7a4a38004f50b4d43a2fae4781f541fe322c249
diff --git a/media/bufferpool/2.0/Observer.cpp b/media/bufferpool/2.0/Observer.cpp
new file mode 100644
index 0000000..5b23160
--- /dev/null
+++ b/media/bufferpool/2.0/Observer.cpp
@@ -0,0 +1,73 @@
+/*
+ * 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.
+ */
+
+#include "Observer.h"
+
+namespace android {
+namespace hardware {
+namespace media {
+namespace bufferpool {
+namespace V2_0 {
+namespace implementation {
+
+Observer::Observer() {
+}
+
+Observer::~Observer() {
+}
+
+// Methods from ::android::hardware::media::bufferpool::V2_0::IObserver follow.
+Return<void> Observer::onMessage(int64_t connectionId, uint32_t msgId) {
+    std::unique_lock<std::mutex> lock(mLock);
+    auto it = mClients.find(connectionId);
+    if (it != mClients.end()) {
+        const std::shared_ptr<BufferPoolClient> client = it->second.lock();
+        if (!client) {
+            mClients.erase(it);
+        } else {
+            lock.unlock();
+            client->receiveInvalidation(msgId);
+        }
+    }
+    return Void();
+}
+
+void Observer::addClient(ConnectionId connectionId,
+                         const std::weak_ptr<BufferPoolClient> &wclient) {
+    std::lock_guard<std::mutex> lock(mLock);
+    for (auto it = mClients.begin(); it != mClients.end();) {
+        if (!it->second.lock() || it->first == connectionId) {
+            it = mClients.erase(it);
+        } else {
+            ++it;
+        }
+    }
+    mClients.insert(std::make_pair(connectionId, wclient));
+
+}
+
+void Observer::delClient(ConnectionId connectionId) {
+    std::lock_guard<std::mutex> lock(mLock);
+    mClients.erase(connectionId);
+}
+
+
+}  // namespace implementation
+}  // namespace V2_0
+}  // namespace bufferpool
+}  // namespace media
+}  // namespace hardware
+}  // namespace android