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      1 /*
      2  * Copyright (C) 2008 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 #include "common_throws.h"
     18 #include "debugger.h"
     19 #include "jni_internal.h"
     20 #include "monitor.h"
     21 #include "mirror/object.h"
     22 #include "scoped_thread_state_change.h"
     23 #include "ScopedUtfChars.h"
     24 #include "thread.h"
     25 #include "thread_list.h"
     26 
     27 namespace art {
     28 
     29 static jobject Thread_currentThread(JNIEnv* env, jclass) {
     30   ScopedObjectAccess soa(env);
     31   return soa.AddLocalReference<jobject>(soa.Self()->GetPeer());
     32 }
     33 
     34 static jboolean Thread_interrupted(JNIEnv* env, jclass) {
     35   return static_cast<JNIEnvExt*>(env)->self->Interrupted() ? JNI_TRUE : JNI_FALSE;
     36 }
     37 
     38 static jboolean Thread_isInterrupted(JNIEnv* env, jobject java_thread) {
     39   ScopedObjectAccess soa(env);
     40   MutexLock mu(soa.Self(), *Locks::thread_list_lock_);
     41   Thread* thread = Thread::FromManagedThread(soa, java_thread);
     42   return (thread != NULL) ? thread->IsInterrupted() : JNI_FALSE;
     43 }
     44 
     45 static void Thread_nativeCreate(JNIEnv* env, jclass, jobject java_thread, jlong stack_size,
     46                                 jboolean daemon) {
     47   Thread::CreateNativeThread(env, java_thread, stack_size, daemon == JNI_TRUE);
     48 }
     49 
     50 static jint Thread_nativeGetStatus(JNIEnv* env, jobject java_thread, jboolean has_been_started) {
     51   // Ordinals from Java's Thread.State.
     52   const jint kJavaNew = 0;
     53   const jint kJavaRunnable = 1;
     54   const jint kJavaBlocked = 2;
     55   const jint kJavaWaiting = 3;
     56   const jint kJavaTimedWaiting = 4;
     57   const jint kJavaTerminated = 5;
     58 
     59   ScopedObjectAccess soa(env);
     60   ThreadState internal_thread_state = (has_been_started ? kTerminated : kStarting);
     61   MutexLock mu(soa.Self(), *Locks::thread_list_lock_);
     62   Thread* thread = Thread::FromManagedThread(soa, java_thread);
     63   if (thread != NULL) {
     64     internal_thread_state = thread->GetState();
     65   }
     66   switch (internal_thread_state) {
     67     case kTerminated:                     return kJavaTerminated;
     68     case kRunnable:                       return kJavaRunnable;
     69     case kTimedWaiting:                   return kJavaTimedWaiting;
     70     case kSleeping:                       return kJavaTimedWaiting;
     71     case kBlocked:                        return kJavaBlocked;
     72     case kWaiting:                        return kJavaWaiting;
     73     case kStarting:                       return kJavaNew;
     74     case kNative:                         return kJavaRunnable;
     75     case kWaitingForGcToComplete:         return kJavaWaiting;
     76     case kWaitingPerformingGc:            return kJavaWaiting;
     77     case kWaitingForCheckPointsToRun:     return kJavaWaiting;
     78     case kWaitingForDebuggerSend:         return kJavaWaiting;
     79     case kWaitingForDebuggerToAttach:     return kJavaWaiting;
     80     case kWaitingInMainDebuggerLoop:      return kJavaWaiting;
     81     case kWaitingForDebuggerSuspension:   return kJavaWaiting;
     82     case kWaitingForJniOnLoad:            return kJavaWaiting;
     83     case kWaitingForSignalCatcherOutput:  return kJavaWaiting;
     84     case kWaitingInMainSignalCatcherLoop: return kJavaWaiting;
     85     case kSuspended:                      return kJavaRunnable;
     86     // Don't add a 'default' here so the compiler can spot incompatible enum changes.
     87   }
     88   return -1;  // Unreachable.
     89 }
     90 
     91 static jboolean Thread_nativeHoldsLock(JNIEnv* env, jobject java_thread, jobject java_object) {
     92   ScopedObjectAccess soa(env);
     93   mirror::Object* object = soa.Decode<mirror::Object*>(java_object);
     94   if (object == NULL) {
     95     ThrowNullPointerException(NULL, "object == null");
     96     return JNI_FALSE;
     97   }
     98   MutexLock mu(soa.Self(), *Locks::thread_list_lock_);
     99   Thread* thread = Thread::FromManagedThread(soa, java_thread);
    100   return thread->HoldsLock(object);
    101 }
    102 
    103 static void Thread_nativeInterrupt(JNIEnv* env, jobject java_thread) {
    104   ScopedObjectAccess soa(env);
    105   MutexLock mu(soa.Self(), *Locks::thread_list_lock_);
    106   Thread* thread = Thread::FromManagedThread(soa, java_thread);
    107   if (thread != NULL) {
    108     thread->Interrupt();
    109   }
    110 }
    111 
    112 static void Thread_nativeSetName(JNIEnv* env, jobject peer, jstring java_name) {
    113   ScopedUtfChars name(env, java_name);
    114   {
    115     ScopedObjectAccess soa(env);
    116     if (soa.Decode<mirror::Object*>(peer) == soa.Self()->GetPeer()) {
    117       soa.Self()->SetThreadName(name.c_str());
    118       return;
    119     }
    120   }
    121   // Suspend thread to avoid it from killing itself while we set its name. We don't just hold the
    122   // thread list lock to avoid this, as setting the thread name causes mutator to lock/unlock
    123   // in the DDMS send code.
    124   bool timed_out;
    125   Thread* thread = Thread::SuspendForDebugger(peer, true, &timed_out);
    126   if (thread != NULL) {
    127     {
    128       ScopedObjectAccess soa(env);
    129       thread->SetThreadName(name.c_str());
    130     }
    131     Runtime::Current()->GetThreadList()->Resume(thread, true);
    132   } else if (timed_out) {
    133     LOG(ERROR) << "Trying to set thread name to '" << name.c_str() << "' failed as the thread "
    134         "failed to suspend within a generous timeout.";
    135   }
    136 }
    137 
    138 /*
    139  * Alter the priority of the specified thread.  "new_priority" will range
    140  * from Thread.MIN_PRIORITY to Thread.MAX_PRIORITY (1-10), with "normal"
    141  * threads at Thread.NORM_PRIORITY (5).
    142  */
    143 static void Thread_nativeSetPriority(JNIEnv* env, jobject java_thread, jint new_priority) {
    144   ScopedObjectAccess soa(env);
    145   MutexLock mu(soa.Self(), *Locks::thread_list_lock_);
    146   Thread* thread = Thread::FromManagedThread(soa, java_thread);
    147   if (thread != NULL) {
    148     thread->SetNativePriority(new_priority);
    149   }
    150 }
    151 
    152 static void Thread_sleep(JNIEnv* env, jclass, jobject java_lock, jlong ms, jint ns) {
    153   ScopedObjectAccess soa(env);
    154   mirror::Object* lock = soa.Decode<mirror::Object*>(java_lock);
    155   Monitor::Wait(Thread::Current(), lock, ms, ns, true, kSleeping);
    156 }
    157 
    158 /*
    159  * Causes the thread to temporarily pause and allow other threads to execute.
    160  *
    161  * The exact behavior is poorly defined.  Some discussion here:
    162  *   http://www.cs.umd.edu/~pugh/java/memoryModel/archive/0944.html
    163  */
    164 static void Thread_yield(JNIEnv*, jobject) {
    165   sched_yield();
    166 }
    167 
    168 static JNINativeMethod gMethods[] = {
    169   NATIVE_METHOD(Thread, currentThread, "()Ljava/lang/Thread;"),
    170   NATIVE_METHOD(Thread, interrupted, "()Z"),
    171   NATIVE_METHOD(Thread, isInterrupted, "()Z"),
    172   NATIVE_METHOD(Thread, nativeCreate, "(Ljava/lang/Thread;JZ)V"),
    173   NATIVE_METHOD(Thread, nativeGetStatus, "(Z)I"),
    174   NATIVE_METHOD(Thread, nativeHoldsLock, "(Ljava/lang/Object;)Z"),
    175   NATIVE_METHOD(Thread, nativeInterrupt, "()V"),
    176   NATIVE_METHOD(Thread, nativeSetName, "(Ljava/lang/String;)V"),
    177   NATIVE_METHOD(Thread, nativeSetPriority, "(I)V"),
    178   NATIVE_METHOD(Thread, sleep, "(Ljava/lang/Object;JI)V"),
    179   NATIVE_METHOD(Thread, yield, "()V"),
    180 };
    181 
    182 void register_java_lang_Thread(JNIEnv* env) {
    183   REGISTER_NATIVE_METHODS("java/lang/Thread");
    184 }
    185 
    186 }  // namespace art
    187