Convert vendor HAL service to use new AIDL interface.

Bug: 205044134
Test: Pass AIDL VTS tests and regression tests.
Change-Id: I286ffbf67efddc6c34d34ebd9e9bd9f36139c962
diff --git a/wifi/aidl/default/aidl_callback_util.h b/wifi/aidl/default/aidl_callback_util.h
new file mode 100644
index 0000000..41d70a5
--- /dev/null
+++ b/wifi/aidl/default/aidl_callback_util.h
@@ -0,0 +1,140 @@
+/*
+ * Copyright (C) 2022 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 AIDL_CALLBACK_UTIL_H_
+#define AIDL_CALLBACK_UTIL_H_
+
+#include <android-base/logging.h>
+
+#include <set>
+#include <unordered_map>
+
+namespace {
+std::unordered_map<void* /* callback */, void* /* handler */> callback_handler_map_;
+}
+
+namespace aidl {
+namespace android {
+namespace hardware {
+namespace wifi {
+namespace aidl_callback_util {
+
+// Provides a class to manage callbacks for the various AIDL interfaces and
+// handle the death of the process hosting each callback.
+template <typename CallbackType>
+class AidlCallbackHandler {
+  public:
+    AidlCallbackHandler() {
+        death_handler_ = AIBinder_DeathRecipient_new(AidlCallbackHandler::onCallbackDeath);
+    }
+    ~AidlCallbackHandler() { invalidate(); }
+
+    bool addCallback(const std::shared_ptr<CallbackType>& cb) {
+        void* cbPtr = reinterpret_cast<void*>(cb->asBinder().get());
+        const auto& cbPosition = findCbInSet(cbPtr);
+        if (cbPosition != cb_set_.end()) {
+            LOG(WARNING) << "Duplicate death notification registration";
+            return true;
+        }
+
+        if (AIBinder_linkToDeath(cb->asBinder().get(), death_handler_, cbPtr /* cookie */) !=
+            STATUS_OK) {
+            LOG(ERROR) << "Failed to register death notification";
+            return false;
+        }
+
+        callback_handler_map_[cbPtr] = reinterpret_cast<void*>(this);
+        cb_set_.insert(cb);
+        return true;
+    }
+
+    const std::set<std::shared_ptr<CallbackType>>& getCallbacks() { return cb_set_; }
+
+    void invalidate() {
+        for (auto cb : cb_set_) {
+            void* cookie = reinterpret_cast<void*>(cb->asBinder().get());
+            if (AIBinder_unlinkToDeath(cb->asBinder().get(), death_handler_, cookie) != STATUS_OK) {
+                LOG(ERROR) << "Failed to deregister death notification";
+            }
+            if (!removeCbFromHandlerMap(cookie)) {
+                LOG(ERROR) << "Failed to remove callback from handler map";
+            }
+        }
+        cb_set_.clear();
+    }
+
+    // Entry point for the death handling logic. AIBinder_DeathRecipient
+    // can only call a static function, so use the cookie to find the
+    // proper handler and route the request there.
+    static void onCallbackDeath(void* cookie) {
+        auto cbQuery = callback_handler_map_.find(cookie);
+        if (cbQuery == callback_handler_map_.end()) {
+            LOG(ERROR) << "Invalid death cookie received";
+            return;
+        }
+
+        AidlCallbackHandler* cbHandler = reinterpret_cast<AidlCallbackHandler*>(cbQuery->second);
+        if (cbHandler == nullptr) {
+            LOG(ERROR) << "Handler mapping contained an invalid handler";
+            return;
+        }
+        cbHandler->handleCallbackDeath(cbQuery->first);
+    }
+
+  private:
+    std::set<std::shared_ptr<CallbackType>> cb_set_;
+    AIBinder_DeathRecipient* death_handler_;
+
+    typename std::set<std::shared_ptr<CallbackType>>::iterator findCbInSet(void* cbPtr) {
+        const auto& cbPosition = std::find_if(
+                cb_set_.begin(), cb_set_.end(), [cbPtr](const std::shared_ptr<CallbackType>& p) {
+                    return cbPtr == reinterpret_cast<void*>(p->asBinder().get());
+                });
+        return cbPosition;
+    }
+
+    bool removeCbFromHandlerMap(void* cbPtr) {
+        auto cbQuery = callback_handler_map_.find(cbPtr);
+        if (cbQuery != callback_handler_map_.end()) {
+            callback_handler_map_.erase(cbQuery);
+            return true;
+        }
+        return false;
+    }
+
+    void handleCallbackDeath(void* cbPtr) {
+        const auto& cbPosition = findCbInSet(cbPtr);
+        if (cbPosition == cb_set_.end()) {
+            LOG(ERROR) << "Unknown callback death notification received";
+            return;
+        }
+        cb_set_.erase(cbPosition);
+
+        if (!removeCbFromHandlerMap(cbPtr)) {
+            LOG(ERROR) << "Callback was not in callback handler map";
+        }
+    }
+
+    DISALLOW_COPY_AND_ASSIGN(AidlCallbackHandler);
+};
+
+}  // namespace aidl_callback_util
+}  // namespace wifi
+}  // namespace hardware
+}  // namespace android
+}  // namespace aidl
+
+#endif  // AIDL_CALLBACK_UTIL_H_