fix Thread.interrupt and Thread.interrupted

These were both totally broken; the latter wasn't even implemented.
This commit fixes/implements them and adds a simple test to exercise
them.

classpath/java/lang/Thread.java

@@ -139,9 +139,17 @@ public class Thread implements Runnable {
 
   public static native Thread currentThread();
 
-  public native void interrupt();
+  public void interrupt() {
+    interrupt(peer);
+  }
 
-  public native boolean interrupted();
+  private static native boolean interrupt(long peer);
+
+  public boolean interrupted() {
+    return interrupted(peer);
+  }
+
+  private static native boolean interrupted(long peer);
 
   public static boolean isInterrupted() {
     return currentThread().interrupted;

src/classpath-avian.cpp

@@ -554,6 +554,15 @@ Avian_java_lang_Thread_interrupt
   interrupt(t, reinterpret_cast<Thread*>(peer));
 }
 
+extern "C" JNIEXPORT int64_t JNICALL
+Avian_java_lang_Thread_interrupted
+(Thread* t, object, uintptr_t* arguments)
+{
+  int64_t peer; memcpy(&peer, arguments, 8);
+
+  return getAndClearInterrupted(t, reinterpret_cast<Thread*>(peer));
+}
+
 extern "C" JNIEXPORT int64_t JNICALL
 Avian_java_lang_Thread_getStackTrace
 (Thread* t, object, uintptr_t* arguments)

src/machine.h

@@ -3236,6 +3236,18 @@ interrupt(Thread* t, Thread* target)
   }
 }
 
+inline bool
+getAndClearInterrupted(Thread* t, Thread* target)
+{
+  if (acquireSystem(t, target)) {
+    bool result = target->systemThread->getAndClearInterrupted();
+    releaseSystem(t, target);
+    return result;
+  } else {
+    return false;
+  }
+}
+
 object
 intern(Thread* t, object s);
 

src/posix.cpp

@@ -151,6 +151,16 @@ class MySystem: public System {
       expect(s, rv == 0);
     }
 
+    virtual bool getAndClearInterrupted() {
+      ACQUIRE(mutex);
+
+      bool interrupted = r->interrupted();
+
+      r->setInterrupted(false);
+
+      return interrupted;
+    }
+
     virtual void join() {
       int rv UNUSED = pthread_join(thread, 0);
       expect(s, rv == 0);

src/system.h

@@ -30,6 +30,7 @@ class System {
   class Thread {
    public:
     virtual void interrupt() = 0;
+    virtual bool getAndClearInterrupted() = 0;
     virtual void join() = 0;
     virtual void dispose() = 0;
   };

src/windows.cpp

@@ -100,6 +100,16 @@ class MySystem: public System {
       }
     }
 
+    virtual bool getAndClearInterrupted() {
+      ACQUIRE(s, mutex);
+
+      bool interrupted = r->interrupted();
+
+      r->setInterrupted(false);
+
+      return interrupted;
+    }
+
     virtual void join() {
       int r UNUSED = WaitForSingleObject(thread, INFINITE);
       assert(s, r == WAIT_OBJECT_0);

test/Threads.java

@@ -1,15 +1,36 @@
 public class Threads implements Runnable {
   public static void main(String[] args) {
-    Threads test = new Threads();
-    Thread thread = new Thread(test);
+    { Threads test = new Threads();
+      Thread thread = new Thread(test);
 
-    try {
-      synchronized (test) {
-        thread.start();
-        test.wait();
+      try {
+        synchronized (test) {
+          thread.start();
+          test.wait();
+        }
+      } catch (Throwable e) {
+        e.printStackTrace();
       }
-    } catch (Throwable e) {
-      e.printStackTrace();
+    }
+
+    { Thread thread = new Thread() {
+        public void run() {
+          while (true) {
+            System.out.print(".");
+            try {
+              sleep(1000);
+            } catch (Exception e) {
+              System.out.println("thread interrupted? " + interrupted());
+              break;
+            }
+          }
+        }
+      };
+      thread.start();
+
+      System.out.println("\nAbout to interrupt...");
+      thread.interrupt();
+      System.out.println("\nInterrupted!");
     }
 
     System.out.println("finished");