1 files changed, 119 insertions, 0 deletions
diff --git a/wifi/1.6/default/hidl_callback_util.h b/wifi/1.6/default/hidl_callback_util.h
new file mode 100644
index 0000000000..3ac54c1666
--- /dev/null
+++ b/wifi/1.6/default/hidl_callback_util.h
@@ -0,0 +1,119 @@
+/*
+ * 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_6 {
+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_6
+}  // namespace wifi
+}  // namespace hardware
+}  // namespace android
+#endif  // HIDL_CALLBACK_UTIL_H_