| // |
| // Copyright 2015 Google, Inc. |
| // |
| // 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. |
| // |
| |
| #pragma once |
| |
| #include <mutex> |
| #include <unordered_map> |
| |
| #include <base/logging.h> |
| #include <base/macros.h> |
| #include <binder/IBinder.h> |
| #include <binder/IInterface.h> |
| |
| namespace ipc { |
| namespace binder { |
| |
| // A map of remote interfaces where the value type "V" must inherit from |
| // android::IInterface. This is just like RemoteCallbackList except it provides |
| // a key-value mapping. |
| // |
| // TODO(armansito): We should make this class non-final and the template |
| // interface abstract, so that code that depends on this can be unit tested |
| // against a mock version of this class. |
| template <typename K, typename V> |
| class RemoteCallbackMap final { |
| public: |
| RemoteCallbackMap() = default; |
| ~RemoteCallbackMap(); |
| |
| // The Delegate interface is used to notify when a registered callback is |
| // removed from the map as a result of the death of the remote process that |
| // owns the registered callback. |
| class Delegate { |
| public: |
| virtual ~Delegate() = default; |
| |
| // Called when a remote callback associated with the key |key| has been |
| // removed. This won't get called if the callback was removed as a result of |
| // a call to RemoteCallbackMap::Unregister. |
| virtual void OnRemoteCallbackRemoved(const K& key) = 0; |
| }; |
| |
| // Register a callback interface and associate it with the given key. |
| // Registering will automatically start tracking for death notifications in |
| // case the remote process hosting the Binder dies. In such a case, the Binder |
| // is automatically removed from the map. |
| // |
| // An optional |delegate| can be passed which will be assocated with the given |
| // key/value pair. |delegate| must outlive this map. |
| bool Register(const K& key, const android::sp<V>& callback, |
| Delegate* delegate = nullptr); |
| |
| // Unregisters a previously registered callback with the given key. Returns |
| // false if |key| doesn't exist. |
| bool Unregister(const K& key); |
| |
| // Returns the callback associated with the given key. Returns NULL if |key| |
| // doesn't exist. |
| android::sp<V> Get(const K& key); |
| |
| // Removes the callback associated with the given key from the map and returns |
| // the value. Returns NULL if the key doesn't exists. |
| android::sp<V> Remove(const K& key); |
| |
| // Clear the contents of the map. |
| void Clear(); |
| |
| private: |
| class CallbackDeathRecipient : public android::IBinder::DeathRecipient { |
| public: |
| CallbackDeathRecipient(const K& key, const android::sp<V>& callback, |
| RemoteCallbackMap<K, V>* owner, Delegate* delegate); |
| |
| android::sp<V> get_callback() const { return callback_; } |
| |
| // android::IBinder::DeathRecipient override: |
| void binderDied(const android::wp<android::IBinder>& who) override; |
| |
| private: |
| K key_; |
| android::sp<V> callback_; |
| RemoteCallbackMap<K, V>* owner_; // weak |
| Delegate* delegate_; // weak |
| }; |
| |
| // Typedef for internal map container. |
| using CallbackMap = |
| std::unordered_map<K, android::sp<CallbackDeathRecipient>>; |
| |
| bool UnregisterInternal(typename CallbackMap::iterator iter); |
| |
| std::mutex map_lock_; |
| CallbackMap map_; |
| |
| DISALLOW_COPY_AND_ASSIGN(RemoteCallbackMap); |
| }; |
| |
| // Template Implementation details below |
| |
| using android::IBinder; |
| using android::IInterface; |
| using android::sp; |
| using android::wp; |
| using std::lock_guard; |
| using std::mutex; |
| |
| template <typename K, typename V> |
| RemoteCallbackMap<K, V>::~RemoteCallbackMap() { |
| Clear(); |
| } |
| |
| template <typename K, typename V> |
| bool RemoteCallbackMap<K, V>::Register(const K& key, const sp<V>& callback, |
| Delegate* delegate) { |
| lock_guard<mutex> lock(map_lock_); |
| |
| if (map_.find(key) != map_.end()) { |
| VLOG(1) << "Callback map already contains key"; |
| return false; |
| } |
| |
| sp<CallbackDeathRecipient> dr( |
| new CallbackDeathRecipient(key, callback, this, delegate)); |
| sp<IBinder> binder = IInterface::asBinder(callback.get()); |
| if (binder->linkToDeath(dr) != android::NO_ERROR) { |
| LOG(ERROR) << "Failed to link death recipient to binder"; |
| return false; |
| } |
| |
| map_[key] = dr; |
| |
| VLOG(2) << "Callback successfully registered with map"; |
| |
| return true; |
| } |
| |
| template <typename K, typename V> |
| bool RemoteCallbackMap<K, V>::Unregister(const K& key) { |
| lock_guard<mutex> lock(map_lock_); |
| |
| auto iter = map_.find(key); |
| if (iter == map_.end()) { |
| VLOG(1) << "Callback with given key not found"; |
| return false; |
| } |
| |
| return UnregisterInternal(iter); |
| } |
| |
| template <typename K, typename V> |
| sp<V> RemoteCallbackMap<K, V>::Get(const K& key) { |
| lock_guard<mutex> lock(map_lock_); |
| |
| auto iter = map_.find(key); |
| if (iter == map_.end()) return nullptr; |
| |
| return iter->second->get_callback(); |
| } |
| |
| template <typename K, typename V> |
| sp<V> RemoteCallbackMap<K, V>::Remove(const K& key) { |
| lock_guard<mutex> lock(map_lock_); |
| |
| auto iter = map_.find(key); |
| if (iter == map_.end()) return nullptr; |
| |
| sp<V> val = iter->second->get_callback(); |
| UnregisterInternal(iter); |
| |
| return val; |
| } |
| template <typename K, typename V> |
| void RemoteCallbackMap<K, V>::Clear() { |
| lock_guard<mutex> lock(map_lock_); |
| |
| for (auto iter = map_.begin(); iter != map_.end();) |
| UnregisterInternal(iter++); |
| } |
| |
| template <typename K, typename V> |
| bool RemoteCallbackMap<K, V>::UnregisterInternal( |
| typename CallbackMap::iterator iter) { |
| sp<CallbackDeathRecipient> dr = iter->second; |
| map_.erase(iter); |
| |
| if (IInterface::asBinder(dr->get_callback().get())->unlinkToDeath(dr) != |
| android::NO_ERROR) { |
| LOG(ERROR) << "Failed to unlink death recipient from binder"; |
| |
| // We removed the entry from |map_| but unlinkToDeath failed. There isn't |
| // really much we can do here other than deleting the binder and returning |
| // an error. |
| return false; |
| } |
| |
| VLOG(2) << "Callback successfully removed from map"; |
| |
| return true; |
| } |
| |
| template <typename K, typename V> |
| RemoteCallbackMap<K, V>::CallbackDeathRecipient::CallbackDeathRecipient( |
| const K& key, const sp<V>& callback, RemoteCallbackMap<K, V>* owner, |
| Delegate* delegate) |
| : key_(key), callback_(callback), owner_(owner), delegate_(delegate) { |
| CHECK(callback_.get()); |
| } |
| |
| template <typename K, typename V> |
| void RemoteCallbackMap<K, V>::CallbackDeathRecipient::binderDied( |
| const wp<IBinder>& who) { |
| VLOG(1) << "Received binderDied"; |
| |
| sp<IBinder> binder = IInterface::asBinder(callback_.get()); |
| CHECK(who.unsafe_get() == binder.get()); |
| |
| // Remove the callback but no need to call unlinkToDeath. |
| { |
| lock_guard<mutex> lock(owner_->map_lock_); |
| auto iter = owner_->map_.find(key_); |
| CHECK(iter != owner_->map_.end()); |
| owner_->map_.erase(iter); |
| } |
| |
| VLOG(1) << "Callback from dead process unregistered; notifying delegate"; |
| |
| // Notify delegate. |
| if (delegate_) delegate_->OnRemoteCallbackRemoved(key_); |
| } |
| |
| } // namespace binder |
| } // namespace ipc |