missing added files from merge

From-SVN: r86958

2 files changed, 411 insertions, 0 deletions

diff --git a/libjava/gnu/java/awt/peer/gtk/GThreadMutex.java b/libjava/gnu/java/awt/peer/gtk/GThreadMutex.java
new file mode 100644
index 0000000..111c9a8
--- /dev/null
+++ b/libjava/gnu/java/awt/peer/gtk/GThreadMutex.java
@@ -0,0 +1,109 @@
+/* GThreadMutex.java -- Implements a mutex object for glib's gthread
+   abstraction, for use with GNU Classpath's --portable-native-sync option.
+   This is used in gthread-jni.c
+   
+   Copyright (C) 2004 Free Software Foundation, Inc.
+
+This file is part of GNU Classpath.
+
+GNU Classpath is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2, or (at your option)
+any later version.
+
+GNU Classpath is distributed in the hope that it will be useful, but
+WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with GNU Classpath; see the file COPYING.  If not, write to the
+Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+02111-1307 USA.
+
+Linking this library statically or dynamically with other modules is
+making a combined work based on this library.  Thus, the terms and
+conditions of the GNU General Public License cover the whole
+combination.
+
+As a special exception, the copyright holders of this library give you
+permission to link this library with independent modules to produce an
+executable, regardless of the license terms of these independent
+modules, and to copy and distribute the resulting executable under
+terms of your choice, provided that you also meet, for each linked
+independent module, the terms and conditions of the license of that
+module.  An independent module is a module which is not derived from
+or based on this library.  If you modify this library, you may extend
+this exception to your version of the library, but you are not
+obligated to do so.  If you do not wish to do so, delete this
+exception statement from your version. */
+
+package gnu.java.awt.peer.gtk;
+
+/** Implements a mutex object for glib's gthread
+    abstraction, for use with GNU Classpath's --portable-native-sync option.
+    This is used in gthread-jni.c.
+
+    We use this object to implement the POSIX semantics for Mutexes.  They are
+    needed are needed for the function vector that is passed to glib's
+    g_thread subpackage's initialization function.
+
+    The GThreadMutex object itself serves as the Real Lock; if code has
+    entered the monitor for this GThreadMutex object (in Java language, if
+    it's synchronized on this object) then it holds the lock that this object
+    represents.
+
+    @author Steven Augart
+    May, 2004
+
+    
+*/
+   
+class GThreadMutex 
+{
+  /** Might "lock" be locked?  Is anyone waiting
+      to get that lock?  How long is the queue?
+
+      If zero, nobody holds a lock on this GThreadMutex object, and nobody is
+      trying to get one.   Before someone attempts to acquire a lock on this
+      object, they must increment potentialLockers.  After they release their
+      lock on this object, they must decrement potentialLockers.
+
+      Access to this field is guarded by synchronizing on the object
+      <code>lockForPotentialLockers</code>.
+
+      After construction, we only access this field via JNI.
+  */
+  volatile int potentialLockers;
+
+  /** An object to synchronize to if you want to examine or modify the
+      <code>potentialLockers</code> field.  Only hold this lock for brief
+      moments, just long enough to check or set the value of
+      <code>lockForPotentialLockers</code>.  
+      
+      We use this representation so that g_thread_mutex_trylock() will work
+      with the POSIX semantics.  This is the only case in which you ever hold a
+      lock on <code>lockForPotentialLockers</code> while trying to get another
+      lock -- if you are the mutex_trylock() implementation, and you have just
+      checked that <code>potentialLockers</code> has the value zero.  In that
+      case, mutex_trylock() holds the lock on lockForPotentialLockers so that
+      another thread calling mutex_trylock() or mutex_lock() won't increment
+      potentialLockers after we've checked it and before we've gained the lock
+      on the POSIX mutex.   Of course, in that case the operation of gaining
+      the POSIX lock itself will succeed immediately, and once it has
+      succeeded, trylock releases lockForPotentialLockers right away,
+      incremented to 1 (one).
+
+      After construction, we only access this field via JNI.
+  */     
+  Object lockForPotentialLockers;
+
+  GThreadMutex() 
+  {
+    potentialLockers = 0;
+    lockForPotentialLockers = new Object();
+  }
+}
+// Local Variables:
+// c-file-style: "gnu"
+// End:
diff --git a/libjava/gnu/java/awt/peer/gtk/GThreadNativeMethodRunner.java b/libjava/gnu/java/awt/peer/gtk/GThreadNativeMethodRunner.java
new file mode 100644
index 0000000..a4cb35a
--- /dev/null
+++ b/libjava/gnu/java/awt/peer/gtk/GThreadNativeMethodRunner.java
@@ -0,0 +1,302 @@
+/* GThreadNativeMethodRunner.java -- Implements pthread_create(), under
+   glib's gthread abstraction, for use with GNU Classpath's
+   --portable-native-sync option. 
+   This is used by gthread-jni.c
+   
+   Copyright (C) 2004 Free Software Foundation, Inc.
+
+This file is part of GNU Classpath.
+
+GNU Classpath is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2, or (at your option)
+any later version.
+
+GNU Classpath is distributed in the hope that it will be useful, but
+WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with GNU Classpath; see the file COPYING.  If not, write to the
+Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+02111-1307 USA.
+
+Linking this library statically or dynamically with other modules is
+making a combined work based on this library.  Thus, the terms and
+conditions of the GNU General Public License cover the whole
+combination.
+
+As a special exception, the copyright holders of this library give you
+permission to link this library with independent modules to produce an
+executable, regardless of the license terms of these independent
+modules, and to copy and distribute the resulting executable under
+terms of your choice, provided that you also meet, for each linked
+independent module, the terms and conditions of the license of that
+module.  An independent module is a module which is not derived from
+or based on this library.  If you modify this library, you may extend
+this exception to your version of the library, but you are not
+obligated to do so.  If you do not wish to do so, delete this
+exception statement from your version. */
+
+package gnu.java.awt.peer.gtk;
+import java.lang.ref.WeakReference;
+import java.util.Set;
+import java.util.Collections;
+import java.util.HashSet;
+
+/** Implements pthread_create(), under glib's gthread abstraction, for use
+    with GNU Classpath's --portable-native-sync option.  This is used in
+    gthread-jni.c
+
+    Also implements a registry for threads, mapping Thread objects to small
+    integers.  The registry uses weak references for threads that aren't
+    joinable, so that they will be garbage collected.
+
+    There are a number of possible alternative implementations.
+    
+    
+    The rest of this comment consists of an answer to a question that was
+    raised on the commit-classpath mailing list:
+
+    Mark Wielaard wrote:
+
+    > Can't we assume that jobject and gpointer are both (void *) so we don't
+    > need the int <-> Thread (global jobject ref) mapping?
+    > Maybe there are platforms where jobject and gpointer aren't the same,
+    > but I guess that is pretty unlikely.
+
+
+    I agree with you on the pointer size issues.  A gpointer is a void *, so
+    it's certainly guaranteed to be at least as large as any other
+    pointer. And a jobject is implicitly an opaque pointer (in Jikes RVM, we
+    use small integers, but we coerce them into the representation of a
+    pointer).
+
+    The int <==> Thread mapping addresses a different issue.  I realize that I
+    did not document this properly (two and a half lines in thread_create),
+    and the point is subtle (at least to me; took me a while to figure out).
+
+    The int => Thread mapping always returns jobjects that are local
+    references, not global ones.  This is because Thread objects need to be
+    able to go away and be garbage collected after the thread they refer to
+    has died.
+
+    If we keep a global object reference to a thread, then when do we delete
+    that global object reference?  We have an answer in the case of GThread
+    objects that were explicitly created with the joinable attribute.  It is
+    safe for us to maintain a global reference to any joinable thread, since
+    the joinable thread must linger (even if only in a zombie state)
+    until it's explicitly joined via a g_thread_join() call.  The global ref
+    could be cleaned up at that point too.
+
+    However, in the case of GThreads that were created non-joinable by
+    g_thread_create(), and in the case of Java threads that were created
+    within pure Java code (not via g_thread_create()), we don't want them to
+    linger forever, and there is no way to tell when the last reference
+    to such threads needs to expire.  In the case of this application -- AWT
+    with GTK peers -- it would probably be safe anyway, since there are not
+    very many threads we create, but I was going for correctness even in the
+    case of long-running programs that might set up and tear down AWT
+    interfaces many times.
+
+    So, I duplicated the POSIX thread-ID semantics.  The thread ID of a
+    non-joinable thread remains valid as long as that thread is still alive.
+    Once that thread dies, the old thread ID may be reused at any moment.  And
+    that's why the array indexed by thread ID numbers is an array of weak
+    references.
+
+    That's also why the int => Thread jobject mapping function always returns
+    local references, since global references would lock the Thread in memory
+    forever.
+
+    I would dearly love there to be a cleaner solution.  I dislike the
+    repeated dips from C code into Java that are necessary to look up thread
+    ID numbers.  If anyone can think of one, I'm all ears.
+*/
+
+class GThreadNativeMethodRunner 
+  extends Thread 
+{
+  /** The C function pointer that was passed to g_thread_create().
+      Specifically, this the numeric address of an object of 
+      C type "void *(*funcPtr)(void *funcArg)".   
+  */
+  private final long funcPtr;
+
+  /** The argument for the function "funcPtr(funcArg)". */
+  private final long funcArg;
+  
+  GThreadNativeMethodRunner(long funcPtr, long funcArg, boolean joinable) 
+  {
+    this.funcPtr = funcPtr;
+    this.funcArg = funcArg;
+
+    if (joinable)
+      registerSelfJoinable();
+  }
+
+  public void run() 
+  {
+    nativeRun(funcPtr, funcArg);
+  }
+
+  private native void nativeRun(long funcPtr, long funcArg);
+
+  /** THREADS is an array of threads, indexed by thread ID codes.  Not sure
+      whether this is the "best" approach but it does make it O(1) to look up a
+      thread by its ID. 
+
+      Zero is a valid thread ID code.  Any negative number is invalid.
+
+      Possible future fixes (TODO?)
+
+     - The THREADS array will only grow. probably not a problem.
+        But we could keep count when nulling entries and shrink when we have
+        lots of nulls at the end. Probably not worth it. --mjw
+
+     - Could make this a set of Object; see the comment on "joinable" below.
+
+     The initial size of 17 is just a starting point.  Any number will do,
+     including zero.
+  */ 
+  private static WeakReference[] threads = new WeakReference[17]; 
+
+  /**  Used by threadToThreadID, below.  Returns the registration number of
+       the newly-registered thread.  
+  */
+  private static synchronized int registerThread(Thread t) 
+  {
+    int i;
+
+    for (i = 0; i < threads.length; ++i) 
+      {
+	WeakReference ref = threads[i];
+	if (ref == null)
+	  break;                  // found an empty spot.
+      }
+
+    if (i == threads.length) 
+      {
+	/* expand the array */
+	WeakReference[] bigger = new WeakReference[threads.length * 2];
+        System.arraycopy(threads, 0, bigger, 0, threads.length);
+	threads = bigger;
+      }
+
+    threads[i] = new WeakReference(t);
+
+    return i;
+  }
+  
+  /**  Look up the Thread ID # for a Thread.  Assign a Thread ID # if none
+       exists.  This is a general routine for handling all threads, including
+       the VM's main thread, if appropriate.
+
+
+       Runs in O(n/2) time.
+
+       We can't just issue a threadID upon thread creation.  If we were to do
+       that, not all threads would have a threadID, because not all threads
+       are launched by GThreadNativeMethodRunner.
+  */ 
+  static synchronized int threadToThreadID(Thread t) 
+  {
+    for (int i = 0; i < threads.length; ++i ) 
+      {
+	if (threads[i] == null)
+	  continue;
+	Thread referent = (Thread) threads[i].get();
+	if (referent == null) 
+	  {
+	    threads[i] = null;      // Purge the dead WeakReference.
+	    continue;
+	  }
+	if (referent.equals(t))
+	  return i;
+      } // for()
+
+    /* No match found. */
+    return registerThread(t);
+  }
+
+  /** @param threadID Must be a non-negative integer.
+
+      Used to return null if the thread number was out of range or if
+      the thread was unregistered.   Now we throw an exception.
+
+      Possible Alternative Interface:  We could go back to returning null in
+           some sort of check-free mode, so code that calls this function must
+           be prepared to get null. 
+  */ 
+  static Thread threadIDToThread(int threadID) 
+    throws IllegalArgumentException
+  {
+    if (threadID < 0)
+      throw new IllegalArgumentException("Received a negative threadID, " 
+					 + threadID); 
+    if (threadID >= threads.length)
+      throw new IllegalArgumentException("Received a threadID (" + threadID 
+					 + ") higher than was" 
+					 + " ever issued"); 
+    
+    /* Note: if the user is using a stale reference, things will just
+       break.    We might end up getting a different thread than the one
+       expected. 
+       
+       TODO: Add an error-checking mode where the user's problems with threads
+          are announced.  For instance, if the user asks for the thread
+          associated with a threadID that was never issued, we could print a
+          warning or even abort.
+       
+       TODO: Consider optionally disabling all of the error-checking we
+          already have; it probably slows down the implementation.  We could
+          just return NULL.  This is just the reverse of the above TODO item.
+    */ 
+
+    WeakReference threadRef = threads[threadID];
+
+    if (threadRef == null)
+      throw new IllegalArgumentException("Asked to look up a stale or unissued"
+					 + "threadID (" + threadID + ")" );
+    
+      
+    Thread referent = (Thread) threadRef.get();
+    if (referent == null)
+      throw new IllegalArgumentException ("Asked to look up a stale threadID ("
+					  + threadID + ")");
+    return referent;
+  }
+  
+  /** Joinable threads need a hard reference, so that they won't go away when
+      they die.  That is because their thread IDs need to stay valid until the
+      thread is joined via thread_join(threadID).  Joinable threads have to be
+      explicitly joined before they are allowed to go away completely.
+
+      Possible Alternative Implementation: Eliminate the Joinable set.  When
+          calling getThreadIDFromThread() you know whether or not the thread
+          is joinable.  So just store the Thread itself in the threads array?
+          Make that array an Object array and check with instanceof.  This
+          looks cleaner and more robust to me and it saves a native -> Java
+          call. But instanceof might be expensive.  --mjw
+  */
+  private static final Set joinable = 
+       Collections.synchronizedSet(new HashSet()); 
+  
+  /** Only called from the constructor. */
+  private void registerSelfJoinable() 
+  {
+    joinable.add(this);
+  }
+  
+  /** This method is only called from JNI, and only after we have succeeded in
+      a thread_join() operation.  */
+  static void deRegisterJoinable(Thread thread) 
+  {
+    joinable.remove(thread);
+  }
+}
+
+// Local Variables:
+// c-file-style: "gnu"
+// End: