Build Android's MessagePumpForUI by upstreaming SystemMessageHandler

BUG=
TEST=The "DumpRenderTree" target on the FYI bot should link.


Review URL: http://codereview.chromium.org/9706022

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@126769 0039d316-1c4b-4281-b951-d872f2087c98

5 files changed, 114 insertions, 59 deletions

diff --git a/base/android/java/org/chromium/base/SystemMessageHandler.java b/base/android/java/org/chromium/base/SystemMessageHandler.java
new file mode 100644
index 0000000..f7bb19f
--- /dev/null
+++ b/base/android/java/org/chromium/base/SystemMessageHandler.java
@@ -0,0 +1,93 @@
+// Copyright (c) 2012 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.
+
+package org.chromium.base;
+
+import android.os.Handler;
+import android.os.Message;
+import android.os.SystemClock;
+
+import java.util.concurrent.atomic.AtomicBoolean;
+
+class SystemMessageHandler extends Handler {
+
+    private static final int TIMER_MESSAGE = 1;
+    private static final int DELAYED_TIMER_MESSAGE = 2;
+
+    // Native class pointer set by the constructor of the SharedClient native class.
+    private int mMessagePumpDelegateNative = 0;
+
+    // Used to ensure we have at most one TIMER_MESSAGE pending at once.
+    private AtomicBoolean mTimerFired = new AtomicBoolean(true);
+
+    // Used to insert TIMER_MESSAGE on the front of the system message queue during startup only.
+    // This is a wee hack, to give a priority boost to native tasks during startup as they tend to
+    // be on the critical path. (After startup, handling the UI with minimum latency is more
+    // important).
+    private boolean mStartupComplete = false;
+    private final long mStartupCompleteTime = System.currentTimeMillis() + 2000;
+    private final boolean startupComplete() {
+        if (!mStartupComplete && System.currentTimeMillis() > mStartupCompleteTime) {
+            mStartupComplete = true;
+        }
+        return mStartupComplete;
+    }
+
+    private SystemMessageHandler(int messagePumpDelegateNative) {
+        mMessagePumpDelegateNative = messagePumpDelegateNative;
+    }
+
+    @Override
+    public void handleMessage(Message msg) {
+        if (msg.what == TIMER_MESSAGE) {
+            mTimerFired.set(true);
+        }
+        while (nativeDoRunLoopOnce(mMessagePumpDelegateNative)) {
+            if (startupComplete()) {
+                setTimer();
+                break;
+            }
+        }
+    }
+
+    @CalledByNative
+    private void setTimer() {
+        if (!mTimerFired.getAndSet(false)) {
+            // mTimerFired was already false.
+            return;
+        }
+        if (startupComplete()) {
+            sendEmptyMessage(TIMER_MESSAGE);
+        } else {
+            sendMessageAtFrontOfQueue(obtainMessage(TIMER_MESSAGE));
+        }
+    }
+
+    // If millis <=0, it'll send a TIMER_MESSAGE instead of
+    // a DELAYED_TIMER_MESSAGE.
+    @SuppressWarnings("unused")
+    @CalledByNative
+    private void setDelayedTimer(long millis) {
+        if (millis <= 0) {
+            setTimer();
+        } else {
+            removeMessages(DELAYED_TIMER_MESSAGE);
+            sendEmptyMessageDelayed(DELAYED_TIMER_MESSAGE, millis);
+        }
+    }
+
+    @SuppressWarnings("unused")
+    @CalledByNative
+    private void removeTimer() {
+        removeMessages(TIMER_MESSAGE);
+        removeMessages(DELAYED_TIMER_MESSAGE);
+    }
+
+    @CalledByNative
+    private static SystemMessageHandler create(int messagePumpDelegateNative) {
+        return new SystemMessageHandler(messagePumpDelegateNative);
+    }
+
+    private native boolean nativeDoRunLoopOnce(int messagePumpDelegateNative);
+}
diff --git a/base/base.gyp b/base/base.gyp
index e3ccc34..e7d8624 100644
--- a/base/base.gyp
+++ b/base/base.gyp
@@ -123,9 +123,11 @@
           'inputs': [
             'android/jni_generator/jni_generator.py',
             'android/java/org/chromium/base/PathUtils.java',
+            'android/java/org/chromium/base/SystemMessageHandler.java',
           ],
           'outputs': [
             '<(SHARED_INTERMEDIATE_DIR)/base/jni/path_utils_jni.h',
+            '<(SHARED_INTERMEDIATE_DIR)/base/jni/system_message_handler_jni.h',
           ],
           'action': [
             'python',
diff --git a/base/base.gypi b/base/base.gypi
index 399b9e8..c4df5b7 100644
--- a/base/base.gypi
+++ b/base/base.gypi
@@ -484,9 +484,6 @@
               ['include', '^sys_info_linux\\.cc$'],
               ['include', '^sys_string_conversions_posix\\.cc$'],
               ['include', '^worker_pool_linux\\.cc$'],
-              # TODO(michaelbai): The below files are excluded because of the
-              # missing JNI, add them back when JNI is ready.
-              ['exclude', '^message_pump_android\\.cc$'],
             ],
           }],
           [ 'OS != "mac"', {
diff --git a/base/message_pump_android.cc b/base/message_pump_android.cc
index 7136eff..2daf98d 100644
--- a/base/message_pump_android.cc
+++ b/base/message_pump_android.cc
@@ -1,4 +1,4 @@
-// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Copyright (c) 2012 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.
 
@@ -7,16 +7,17 @@
 #include <jni.h>
 
 #include "base/android/jni_android.h"
+#include "base/android/scoped_java_ref.h"
+#include "base/lazy_instance.h"
 #include "base/logging.h"
 #include "jni/system_message_handler_jni.h"
 
-using base::android::ScopedJavaReference;
+using base::android::ScopedJavaLocalRef;
 
 namespace {
 
-const char* kClassPathName = "com/android/chromeview/base/SystemMessageHandler";
-
-jobject g_system_message_handler_obj = NULL;
+base::LazyInstance<base::android::ScopedJavaGlobalRef<jobject> >
+    g_system_message_handler_obj = LAZY_INSTANCE_INITIALIZER;
 
 }  // namespace
 
@@ -53,7 +54,6 @@ static jboolean DoRunLoopOnce(JNIEnv* env, jobject obj, jint native_delegate) {
     jlong millis =
         (delayed_work_time - base::TimeTicks::Now()).InMillisecondsRoundedUp();
     Java_SystemMessageHandler_setDelayedTimer(env, obj, millis);
-    base::android::CheckException(env);
   }
   return more_work_is_plausible;
 }
@@ -75,34 +75,23 @@ void MessagePumpForUI::Run(Delegate* delegate) {
 void MessagePumpForUI::Start(Delegate* delegate) {
   state_ = new MessageLoop::AutoRunState(MessageLoop::current());
 
-  DCHECK(!g_system_message_handler_obj);
+  DCHECK(g_system_message_handler_obj.Get().is_null());
 
   JNIEnv* env = base::android::AttachCurrentThread();
   DCHECK(env);
 
-  jclass clazz = env->FindClass(kClassPathName);
-  DCHECK(clazz);
-
-  jmethodID constructor = base::android::GetMethodID(env, clazz, "<init>",
-                                                     "(I)V");
-  ScopedJavaReference<jobject> client(env, env->NewObject(clazz, constructor,
-                                                          delegate));
-  DCHECK(client.obj());
-
-  g_system_message_handler_obj = env->NewGlobalRef(client.obj());
-
-  base::android::CheckException(env);
+  g_system_message_handler_obj.Get().Reset(
+      Java_SystemMessageHandler_create(env, reinterpret_cast<jint>(delegate)));
 }
 
 void MessagePumpForUI::Quit() {
-  if (g_system_message_handler_obj) {
+  if (!g_system_message_handler_obj.Get().is_null()) {
     JNIEnv* env = base::android::AttachCurrentThread();
     DCHECK(env);
 
-    Java_SystemMessageHandler_removeTimer(env, g_system_message_handler_obj);
-    env->DeleteGlobalRef(g_system_message_handler_obj);
-    base::android::CheckException(env);
-    g_system_message_handler_obj = NULL;
+    Java_SystemMessageHandler_removeTimer(env,
+        g_system_message_handler_obj.Get().obj());
+    g_system_message_handler_obj.Get().Reset();
   }
 
   if (state_) {
@@ -112,19 +101,18 @@ void MessagePumpForUI::Quit() {
 }
 
 void MessagePumpForUI::ScheduleWork() {
-  if (!g_system_message_handler_obj)
+  if (g_system_message_handler_obj.Get().is_null())
     return;
 
   JNIEnv* env = base::android::AttachCurrentThread();
   DCHECK(env);
 
-  Java_SystemMessageHandler_setTimer(env, g_system_message_handler_obj);
-  base::android::CheckException(env);
-
+  Java_SystemMessageHandler_setTimer(env,
+      g_system_message_handler_obj.Get().obj());
 }
 
 void MessagePumpForUI::ScheduleDelayedWork(const TimeTicks& delayed_work_time) {
-  if (!g_system_message_handler_obj)
+  if (g_system_message_handler_obj.Get().is_null())
     return;
 
   JNIEnv* env = base::android::AttachCurrentThread();
@@ -134,9 +122,8 @@ void MessagePumpForUI::ScheduleDelayedWork(const TimeTicks& delayed_work_time) {
       (delayed_work_time - base::TimeTicks::Now()).InMillisecondsRoundedUp();
   // Note that we're truncating to milliseconds as required by the java side,
   // even though delayed_work_time is microseconds resolution.
-  Java_SystemMessageHandler_setDelayedTimer(env, g_system_message_handler_obj,
-                                            millis);
-  base::android::CheckException(env);
+  Java_SystemMessageHandler_setDelayedTimer(env,
+      g_system_message_handler_obj.Get().obj(), millis);
 }
 
 // Register native methods
diff --git a/base/test/test_stub_android.cc b/base/test/test_stub_android.cc
index c806e22..be45e42 100644
--- a/base/test/test_stub_android.cc
+++ b/base/test/test_stub_android.cc
@@ -178,27 +178,3 @@ void InitAndroidTestStub() {
 
   MessageLoop::InitMessagePumpForUIFactory(&CreateMessagePumpForUIStub);
 }
-
-namespace base {
-
-// TODO(michaelbai): The below MessagePumpForUI were added because we excluded
-// message_pump_android.{h|cc} which require JNI to compile. Remove them when
-// those 2 files added.
-MessagePumpForUI::MessagePumpForUI()
-    : state_(NULL) {
-}
-
-MessagePumpForUI::~MessagePumpForUI() {}
-
-void MessagePumpForUI::Run(Delegate* delegate) {}
-
-void MessagePumpForUI::Start(Delegate* delegate) {}
-
-void MessagePumpForUI::Quit() {}
-
-void MessagePumpForUI::ScheduleWork() {}
-
-void MessagePumpForUI::ScheduleDelayedWork(const TimeTicks& delayed_work_time) {
-}
-
-}  // namespace base