Implement BroadcastChannel

components/webmessaging/broadcast_channel_service.cc

+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "components/webmessaging/broadcast_channel_service.h"
+
+#include "base/bind.h"
+#include "base/stl_util.h"
+#include "mojo/public/cpp/bindings/associated_binding.h"
+#include "mojo/public/cpp/bindings/interface_ptr_set.h"
+#include "mojo/public/cpp/bindings/strong_binding.h"
+
+namespace webmessaging {
+
+// Connections are owned by the BroadcastChannelService, but can also destroy
+// and unregister themselves if the connection is disconnected.
+class BroadcastChannelService::Connection
+    : public mojom::BroadcastChannelService {
+ public:
+  Connection(mojom::BroadcastChannelServiceRequest request,
+             webmessaging::BroadcastChannelService* service)
+      : binding_(this, std::move(request)), service_(service) {}
+
+  ~Connection() override { service_->UnregisterConnection(this); }
+
+  void Subscribe(
+      const url::Origin& origin,
+      const mojo::String& name,
+      mojom::BroadcastChannelClientAssociatedPtrInfo clientInfo) override {
+    mojom::BroadcastChannelClientAssociatedPtr client;
+    client.Bind(std::move(clientInfo));
+    subscriptions_[ChannelKey(origin, name)].AddPtr(std::move(client));
+  }
+
+  void Broadcast(const url::Origin& origin,
+                 const mojo::String& name,
+                 const mojo::String& message) override {
+    service_->ReceivedMessageOnConnection(this, origin, name, message);
+  }
+
+  void DispatchMessage(const url::Origin& origin,
+                       const mojo::String& name,
+                       const mojo::String& message) {
+    auto it = subscriptions_.find(ChannelKey(origin, name));
+    if (it == subscriptions_.end())
+      return;
+    it->second.ForAllPtrs([message](mojom::BroadcastChannelClient* client) {
+      client->OnMessage(message);
+    });
+  }
+
+ private:
+  using ChannelKey = std::pair<url::Origin, std::string>;
+  std::map<ChannelKey,
+           mojo::AssociatedInterfacePtrSet<mojom::BroadcastChannelClient>>
+      subscriptions_;
+  mojo::StrongBinding<mojom::BroadcastChannelService> binding_;
+  webmessaging::BroadcastChannelService* service_;
+};
+
+BroadcastChannelService::BroadcastChannelService() {}
+
+void BroadcastChannelService::Connect(
+    mojom::BroadcastChannelServiceRequest request) {
+  connections_.insert(new Connection(std::move(request), this));
+}
+
+BroadcastChannelService::~BroadcastChannelService() {
+  STLDeleteElements(&connections_);
+}
+
+void BroadcastChannelService::UnregisterConnection(Connection* c) {
+  connections_.erase(c);
+}
+
+void BroadcastChannelService::ReceivedMessageOnConnection(
+    Connection* from,
+    const url::Origin& origin,
+    const mojo::String& name,
+    const mojo::String& message) {
+  for (Connection* c : connections_) {
+    if (c != from)
+      c->DispatchMessage(origin, name, message);
+  }
+}
+
+}  // namespace webmessaging