HTML MessagePort as mojo::MessagePipeHandle

content/browser/android/app_web_message_port.cc

+// Copyright 2017 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 "content/browser/android/app_web_message_port.h"
+
+#include "base/android/jni_android.h"
+#include "base/android/jni_string.h"
+#include "base/bind.h"
+#include "content/browser/android/string_message_codec.h"
+#include "jni/AppWebMessagePort_jni.h"
+
+namespace content {
+
+// static
+void AppWebMessagePort::CreateAndBindToJavaObject(
+    JNIEnv* env,
+    mojo::ScopedMessagePipeHandle handle,
+    const base::android::JavaRef<jobject>& jobject) {
+  AppWebMessagePort* instance =
+      new AppWebMessagePort(env, std::move(handle), jobject);
+  Java_AppWebMessagePort_setNativeAppWebMessagePort(
+      env, jobject, reinterpret_cast<jlong>(instance));
+}
+
+// static
+std::vector<MessagePort> AppWebMessagePort::UnwrapJavaArray(
+    JNIEnv* env,
+    const base::android::JavaRef<jobjectArray>& jports) {
+  std::vector<MessagePort> ports;
+  if (!jports.is_null()) {
+    jsize num_ports = env->GetArrayLength(jports.obj());
+    for (jsize i = 0; i < num_ports; ++i) {
+      base::android::ScopedJavaLocalRef<jobject> jport(
+          env, env->GetObjectArrayElement(jports.obj(), i));
+      jlong native_port =
+          Java_AppWebMessagePort_releaseNativePortForTransfer(env, jport);
+      // Uninitialized ports should be trapper earlier at the Java layer.
+      DCHECK(native_port != -1);
+      AppWebMessagePort* instance =
+          reinterpret_cast<AppWebMessagePort*>(native_port);
+      ports.push_back(instance->port_);  // Transfers ownership.
+      delete instance;
+    }
+  }
+  return ports;
+}
+
+void AppWebMessagePort::CloseMessagePort(
+    JNIEnv* env,
+    const base::android::JavaParamRef<jobject>& jcaller) {
+  // Explicitly reset the port here to ensure that OnMessagesAvailable has
+  // finished before we destroy this.
+  port_ = MessagePort();
+
+  delete this;
+}
+
+void AppWebMessagePort::PostMessage(
+    JNIEnv* env,
+    const base::android::JavaParamRef<jobject>& jcaller,
+    const base::android::JavaParamRef<jstring>& jmessage,
+    const base::android::JavaParamRef<jobjectArray>& jports) {
+  port_.PostMessage(
+      EncodeStringMessage(base::android::ConvertJavaStringToUTF16(jmessage)),
+      UnwrapJavaArray(env, jports));
+}
+
+jboolean AppWebMessagePort::DispatchNextMessage(
+    JNIEnv* env,
+    const base::android::JavaParamRef<jobject>& jcaller) {
+  base::android::ScopedJavaLocalRef<jobject> obj = java_ref_.get(env);
+  if (obj.is_null())
+    return false;
+
+  jmethodID app_web_message_port_constructor =
+      base::android::MethodID::Get<base::android::MethodID::TYPE_INSTANCE>(
+          env, AppWebMessagePort_clazz(env), "<init>", "()V");
+
+  base::string16 encoded_message;
+  std::vector<MessagePort> ports;
+  if (!port_.GetMessage(&encoded_message, &ports))
+    return false;
+
+  base::string16 message;
+  if (!DecodeStringMessage(encoded_message, &message))
+    return false;
+
+  base::android::ScopedJavaLocalRef<jstring> jmessage =
+      base::android::ConvertUTF16ToJavaString(env, message);
+
+  base::android::ScopedJavaLocalRef<jobjectArray> jports;
+  if (ports.size() > 0) {
+    jports = base::android::ScopedJavaLocalRef<jobjectArray>(
+        env,
+        env->NewObjectArray(ports.size(),
+                            AppWebMessagePort_clazz(env),
+                            nullptr));
+
+    // Instantiate the Java and C++ wrappers for the transferred ports.
+    for (size_t i = 0; i < ports.size(); ++i) {
+      base::android::ScopedJavaLocalRef<jobject> jport(
+          env,
+          env->NewObject(AppWebMessagePort_clazz(env),
+                         app_web_message_port_constructor));
+      CreateAndBindToJavaObject(env, ports[i].ReleaseHandle(), jport);
+
+      env->SetObjectArrayElement(jports.obj(), i, jport.obj());
+    }
+  }
+
+  Java_AppWebMessagePort_onReceivedMessage(env, obj, jmessage, jports);
+  return true;
+}
+
+void AppWebMessagePort::StartReceivingMessages(
+    JNIEnv* env,
+    const base::android::JavaParamRef<jobject>& jcaller) {
+  port_.SetCallback(
+      base::Bind(&AppWebMessagePort::OnMessagesAvailable,
+                 base::Unretained(this)));
+}
+
+AppWebMessagePort::AppWebMessagePort(
+    JNIEnv* env,
+    mojo::ScopedMessagePipeHandle handle,
+    const base::android::JavaRef<jobject>& jobject)
+    : port_(std::move(handle)),
+      java_ref_(env, jobject) {
+}
+
+AppWebMessagePort::~AppWebMessagePort() {
+}
+
+void AppWebMessagePort::OnMessagesAvailable() {
+  // Called on a background thread.
+  JNIEnv* env = base::android::AttachCurrentThread();
+  base::android::ScopedJavaLocalRef<jobject> obj = java_ref_.get(env);
+  if (obj.is_null())
+    return;
+  Java_AppWebMessagePort_onMessagesAvailable(env, obj);
+}
+
+bool RegisterAppWebMessagePort(JNIEnv* env) {
+  return RegisterNativesImpl(env);
+}
+
+void InitializeAppWebMessagePortPair(
+    JNIEnv* env,
+    const base::android::JavaParamRef<jclass>& jcaller,
+    const base::android::JavaParamRef<jobjectArray>& ports) {
+  DCHECK_EQ(2, env->GetArrayLength(ports.obj()));
+
+  mojo::MessagePipe pipe;
+
+  base::android::ScopedJavaLocalRef<jobject> jport0(
+      env, env->GetObjectArrayElement(ports.obj(), 0));
+  AppWebMessagePort::CreateAndBindToJavaObject(
+      env, std::move(pipe.handle0), jport0);
+
+  base::android::ScopedJavaLocalRef<jobject> jport1(
+      env, env->GetObjectArrayElement(ports.obj(), 1));
+  AppWebMessagePort::CreateAndBindToJavaObject(
+      env, std::move(pipe.handle1), jport1);
+}
+
+}  // namespace content