wifi(implementation): Callback death handler
Add a new utility to handle callback death notifications. The new class
HidlCallbackHandler will be used by all the HIDL interface objects to
manage callbacks. Any dead clients will automatically removed from the
cb list by the utility class.
Bug: 34840719
Test: Compiles
Test: Verified that the cbs are deleted on crashing the framework
manually
Change-Id: I0f7ba8b3ed717c2e8e8fbf744a2501d0ad2d48c8
diff --git a/wifi/1.0/default/hidl_callback_util.h b/wifi/1.0/default/hidl_callback_util.h
new file mode 100644
index 0000000..a1c6819
--- /dev/null
+++ b/wifi/1.0/default/hidl_callback_util.h
@@ -0,0 +1,123 @@
+/*
+ * Copyright (C) 2017 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 HIDL_CALLBACK_UTIL_H_
+#define HIDL_CALLBACK_UTIL_H_
+
+#include <set>
+
+#include <hidl/HidlSupport.h>
+
+namespace {
+// Type of callback invoked by the death handler.
+using on_death_cb_function = std::function<void(uint64_t)>;
+
+// Private class used to keep track of death of individual
+// callbacks stored in HidlCallbackHandler.
+template <typename CallbackType>
+class HidlDeathHandler : public android::hardware::hidl_death_recipient {
+ public:
+ HidlDeathHandler(const on_death_cb_function& user_cb_function)
+ : cb_function_(user_cb_function) {}
+ ~HidlDeathHandler() = default;
+
+ // Death notification for callbacks.
+ void serviceDied(
+ uint64_t cookie,
+ const android::wp<android::hidl::base::V1_0::IBase>& /* who */) override {
+ cb_function_(cookie);
+ }
+
+ private:
+ on_death_cb_function cb_function_;
+
+ DISALLOW_COPY_AND_ASSIGN(HidlDeathHandler);
+};
+} // namespace
+
+namespace android {
+namespace hardware {
+namespace wifi {
+namespace V1_0 {
+namespace implementation {
+namespace hidl_callback_util {
+template <typename CallbackType>
+// Provides a class to manage callbacks for the various HIDL interfaces and
+// handle the death of the process hosting each callback.
+class HidlCallbackHandler {
+ public:
+ HidlCallbackHandler()
+ : death_handler_(new HidlDeathHandler<CallbackType>(
+ std::bind(&HidlCallbackHandler::onObjectDeath,
+ this,
+ std::placeholders::_1))) {}
+ ~HidlCallbackHandler() = default;
+
+ bool addCallback(const sp<CallbackType>& cb) {
+ // TODO(b/33818800): Can't compare proxies yet. So, use the cookie
+ // (callback proxy's raw pointer) to track the death of individual clients.
+ uint64_t cookie = reinterpret_cast<uint64_t>(cb.get());
+ if (cb_set_.find(cb) != cb_set_.end()) {
+ LOG(WARNING) << "Duplicate death notification registration";
+ return true;
+ }
+ if (!cb->linkToDeath(death_handler_, cookie)) {
+ LOG(ERROR) << "Failed to register death notification";
+ return false;
+ }
+ cb_set_.insert(cb);
+ return true;
+ }
+
+ const std::set<android::sp<CallbackType>> getCallbacks() {
+ return cb_set_;
+ }
+
+ // Death notification for callbacks.
+ void onObjectDeath(uint64_t cookie) {
+ CallbackType *cb = reinterpret_cast<CallbackType*>(cookie);
+ const auto& iter = cb_set_.find(cb);
+ if (iter == cb_set_.end()) {
+ LOG(ERROR) << "Unknown callback death notification received";
+ return;
+ }
+ cb_set_.erase(iter);
+ LOG(DEBUG) << "Dead callback removed from list";
+ }
+
+ void invalidate() {
+ for (const sp<CallbackType>& cb : cb_set_) {
+ if (!cb->unlinkToDeath(death_handler_)) {
+ LOG(ERROR) << "Failed to deregister death notification";
+ }
+ }
+ cb_set_.clear();
+ }
+
+ private:
+ std::set<sp<CallbackType>> cb_set_;
+ sp<HidlDeathHandler<CallbackType>> death_handler_;
+
+ DISALLOW_COPY_AND_ASSIGN(HidlCallbackHandler);
+};
+
+} // namespace hidl_callback_util
+} // namespace implementation
+} // namespace V1_0
+} // namespace wifi
+} // namespace hardware
+} // namespace android
+#endif // HIDL_CALLBACK_UTIL_H_