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      1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 #include "base/message_loop/message_pump_android.h"
      6 
      7 #include <jni.h>
      8 
      9 #include "base/android/jni_android.h"
     10 #include "base/android/scoped_java_ref.h"
     11 #include "base/lazy_instance.h"
     12 #include "base/logging.h"
     13 #include "base/run_loop.h"
     14 #include "base/time/time.h"
     15 #include "jni/SystemMessageHandler_jni.h"
     16 
     17 using base::android::ScopedJavaLocalRef;
     18 
     19 // ----------------------------------------------------------------------------
     20 // Native JNI methods called by Java.
     21 // ----------------------------------------------------------------------------
     22 // This method can not move to anonymous namespace as it has been declared as
     23 // 'static' in system_message_handler_jni.h.
     24 static void DoRunLoopOnce(JNIEnv* env, jobject obj, jint native_delegate) {
     25   base::MessagePump::Delegate* delegate =
     26       reinterpret_cast<base::MessagePump::Delegate*>(native_delegate);
     27   DCHECK(delegate);
     28   // This is based on MessagePumpForUI::DoRunLoop() from desktop.
     29   // Note however that our system queue is handled in the java side.
     30   // In desktop we inspect and process a single system message and then
     31   // we call DoWork() / DoDelayedWork().
     32   // On Android, the java message queue may contain messages for other handlers
     33   // that will be processed before calling here again.
     34   bool did_work = delegate->DoWork();
     35 
     36   // This is the time when we need to do delayed work.
     37   base::TimeTicks delayed_work_time;
     38   did_work |= delegate->DoDelayedWork(&delayed_work_time);
     39 
     40   // Always call this if there is a delayed message waiting in the queue
     41   // since is at most one delayed message in the Java message handler, and this
     42   // function call may be the result of that message being handled.
     43   if (!delayed_work_time.is_null()) {
     44     Java_SystemMessageHandler_setDelayedTimer(env, obj,
     45         (delayed_work_time - base::TimeTicks::Now()).InMillisecondsRoundedUp());
     46   }
     47 
     48   // This is a major difference between android and other platforms: since we
     49   // can't inspect it and process just one single message, instead we'll yeld
     50   // the callstack.
     51   if (did_work)
     52     return;
     53 
     54   delegate->DoIdleWork();
     55 }
     56 
     57 namespace base {
     58 
     59 MessagePumpForUI::MessagePumpForUI()
     60     : run_loop_(NULL) {
     61 }
     62 
     63 MessagePumpForUI::~MessagePumpForUI() {
     64 }
     65 
     66 void MessagePumpForUI::Run(Delegate* delegate) {
     67   NOTREACHED() << "UnitTests should rely on MessagePumpForUIStub in"
     68       " test_stub_android.h";
     69 }
     70 
     71 void MessagePumpForUI::Start(Delegate* delegate) {
     72   run_loop_ = new RunLoop();
     73   // Since the RunLoop was just created above, BeforeRun should be guaranteed to
     74   // return true (it only returns false if the RunLoop has been Quit already).
     75   if (!run_loop_->BeforeRun())
     76     NOTREACHED();
     77 
     78   DCHECK(system_message_handler_obj_.is_null());
     79 
     80   JNIEnv* env = base::android::AttachCurrentThread();
     81   DCHECK(env);
     82 
     83   system_message_handler_obj_.Reset(
     84       Java_SystemMessageHandler_create(env, reinterpret_cast<jint>(delegate)));
     85 }
     86 
     87 void MessagePumpForUI::Quit() {
     88   if (!system_message_handler_obj_.is_null()) {
     89     JNIEnv* env = base::android::AttachCurrentThread();
     90     DCHECK(env);
     91 
     92     Java_SystemMessageHandler_removeTimer(env,
     93         system_message_handler_obj_.obj());
     94     system_message_handler_obj_.Reset();
     95   }
     96 
     97   if (run_loop_) {
     98     run_loop_->AfterRun();
     99     delete run_loop_;
    100     run_loop_ = NULL;
    101   }
    102 }
    103 
    104 void MessagePumpForUI::ScheduleWork() {
    105   DCHECK(!system_message_handler_obj_.is_null());
    106 
    107   JNIEnv* env = base::android::AttachCurrentThread();
    108   DCHECK(env);
    109 
    110   Java_SystemMessageHandler_setTimer(env,
    111       system_message_handler_obj_.obj());
    112 }
    113 
    114 void MessagePumpForUI::ScheduleDelayedWork(const TimeTicks& delayed_work_time) {
    115   DCHECK(!system_message_handler_obj_.is_null());
    116 
    117   JNIEnv* env = base::android::AttachCurrentThread();
    118   DCHECK(env);
    119 
    120   jlong millis =
    121       (delayed_work_time - TimeTicks::Now()).InMillisecondsRoundedUp();
    122   // Note that we're truncating to milliseconds as required by the java side,
    123   // even though delayed_work_time is microseconds resolution.
    124   Java_SystemMessageHandler_setDelayedTimer(env,
    125       system_message_handler_obj_.obj(), millis);
    126 }
    127 
    128 // static
    129 bool MessagePumpForUI::RegisterBindings(JNIEnv* env) {
    130   return RegisterNativesImpl(env);
    131 }
    132 
    133 }  // namespace base
    134