Re: [JVMTI] RFA: Implement GetAllThreads

[Kyle Galloway <kgallowa at redhat dot com>]

Keith responded to this off-list with some comments.  I have made some 
small changes, mostly some additional error checking, and a few 
formatting things I missed.  I also expanded the test case to a larger 
number of threads (22 instead of 3).  New patch is attached.

Comments, or is this ok to commit?

Kyle

2006-10-05  Kyle Galloway  <kgallowa@redhat.com>

   * jvmti.cc (_Jv_JVMTI_GetAllThreads): New method.
   * testsuite/getallthreads.java: New test.
   * testsuite/natgetallthreads.cc: Ditto.
   * testsuite/getallthreads.out: Output file for test.


Index: libjava/testsuite/libjava.jvmti/getallthreads.java
===================================================================
--- libjava/testsuite/libjava.jvmti/getallthreads.java	(revision 0)
+++ libjava/testsuite/libjava.jvmti/getallthreads.java	(revision 0)
@@ -0,0 +1,47 @@
+// Test JVMTI GetAllThreads method
+
+public class getallthreads extends Thread
+{
+  private boolean loop;
+  
+  public getallthreads ()
+  {
+    super ();
+    loop = true;
+  }
+  
+  public void run ()
+  {
+    while (loop)
+    {
+      try
+        {
+    	  sleep (100);
+        }
+      catch (Throwable t)
+        {
+        }
+    }
+  }
+  
+  public void done ()
+  {
+	loop = false;
+  }
+
+  public static native void do_getallthreads_tests ();
+
+  public static void main (String[] args)
+  {
+    System.out.println ("JVMTI GetAllThreads test");
+    getallthreads[] t = new getallthreads[20];
+    for (int i = 0; i < 20; i++)
+      {
+        t[i] = new getallthreads ();
+        t[i].start ();
+      }
+    do_getallthreads_tests ();
+    for (int i = 0; i < 20; i++)
+      t[i].done ();
+  }
+}
Index: libjava/testsuite/libjava.jvmti/getallthreads.out
===================================================================
--- libjava/testsuite/libjava.jvmti/getallthreads.out	(revision 0)
+++ libjava/testsuite/libjava.jvmti/getallthreads.out	(revision 0)
@@ -0,0 +1,27 @@
+JVMTI GetAllThreads test
+Threads:
+
+Found thread 0
+Found thread 1
+Found thread 2
+Found thread 3
+Found thread 4
+Found thread 5
+Found thread 6
+Found thread 7
+Found thread 8
+Found thread 9
+Found thread 10
+Found thread 11
+Found thread 12
+Found thread 13
+Found thread 14
+Found thread 15
+Found thread 16
+Found thread 17
+Found thread 18
+Found thread 19
+Found thread 20
+Found thread 21
+
+Thread count: 22
Index: libjava/testsuite/libjava.jvmti/natgetallthreads.cc
===================================================================
--- libjava/testsuite/libjava.jvmti/natgetallthreads.cc	(revision 0)
+++ libjava/testsuite/libjava.jvmti/natgetallthreads.cc	(revision 0)
@@ -0,0 +1,36 @@
+#include <gcj/cni.h>
+
+#include <jvm.h>
+#include <jvmti.h>
+#include <stdio.h>
+
+#include "jvmti-int.h"
+#include "getallthreads.h"
+
+static void
+print_threads (jthread *threads, jint threadCount)
+{
+  printf ("Threads:\n\n");
+  
+  java::lang::Thread *t = NULL;
+  
+  for (int i = 0; i < threadCount; i++)
+    {
+      printf ("Found thread %d\n", i);
+    }
+    
+  printf ("\nThread count: %d\n", (int) threadCount);
+}
+
+void
+getallthreads::do_getallthreads_tests ()
+{
+  jvmtiEnv *env;
+  JavaVM *vm = _Jv_GetJavaVM ();
+  vm->GetEnv (reinterpret_cast<void **> (&env), JVMTI_VERSION_1_0);
+  jthread *threads;
+  jint threadCount;
+  env->GetAllThreads (&threadCount, &threads);
+  print_threads (threads, threadCount);
+  env->Deallocate (reinterpret_cast<unsigned char *> (threads));
+}
Index: libjava/jvmti.cc
===================================================================
--- libjava/jvmti.cc	(revision 117434)
+++ libjava/jvmti.cc	(working copy)
@@ -24,7 +24,9 @@
 #include <java/lang/Class.h>
 #include <java/lang/ClassLoader.h>
 #include <java/lang/Object.h>
+#include <java/lang/OutOfMemoryError.h>
 #include <java/lang/Thread.h>
+#include <java/lang/ThreadGroup.h>
 #include <java/lang/Throwable.h>
 #include <java/lang/VMClassLoader.h>
 #include <java/lang/reflect/Field.h>
@@ -103,7 +105,61 @@
 	return JVMTI_ERROR_ILLEGAL_ARGUMENT;	\
     }						\
   while (0)
+  
+static jvmtiError JNICALL
+_Jv_JVMTI_GetAllThreads(MAYBE_UNUSED jvmtiEnv *env, jint *threadCount,
+                        jthread **threads)
+{
+  REQUIRE_PHASE (env, JVMTI_PHASE_LIVE);
+  NULL_CHECK (threadCount);
+  NULL_CHECK (threads);
+  
+  using namespace java::lang;
+  Thread *thr = Thread::currentThread ();
+  
+  ThreadGroup *thrGrp = thr->getThreadGroup ();
+  ThreadGroup *parent = thrGrp->getParent ();
+  
+  //get the root thread group
+  while (parent != NULL)
+    {
+      thrGrp = parent;
+      parent = thrGrp->getParent ();
+    }
+  
+  jint estimate = thrGrp->activeCount ();
+  
+  JArray<Thread *> *thrArray;
 
+  //allocate some extra space since threads can be created between calls
+  try
+    { 
+      thrArray = (JArray<Thread *> *) JvNewObjectArray ((estimate * 2),
+                  &Thread::class$, NULL);
+    }
+  catch (java::lang::OutOfMemoryError *err)
+    {
+      return JVMTI_ERROR_OUT_OF_MEMORY;
+    }
+   
+  (*threadCount) = thrGrp->enumerate (thrArray);
+  
+  jvmtiError ret
+    = env->Allocate ((jlong) ((*threadCount) * sizeof (jthread)),
+                     reinterpret_cast<unsigned char **> (threads));
+
+  if (ret != JVMTI_ERROR_NONE)
+    return ret;
+  
+  //now transfer the threads to the result array
+  jthread *tArrPtr = (*threads);
+  jthread *tmpArr = (jthread *) elements (thrArray);
+
+  memcpy (tArrPtr, tmpArr, (*threadCount));
+  
+  return JVMTI_ERROR_NONE;
+}
+
 static jvmtiError JNICALL
 _Jv_JVMTI_SuspendThread (MAYBE_UNUSED jvmtiEnv *env, jthread thread)
 {
@@ -1187,7 +1243,7 @@
   RESERVED,			// reserved1
   _Jv_JVMTI_SetEventNotificationMode, // SetEventNotificationMode
   RESERVED,			// reserved3
-  UNIMPLEMENTED,		// GetAllThreads
+  _Jv_JVMTI_GetAllThreads,		// GetAllThreads
   _Jv_JVMTI_SuspendThread,	// SuspendThread
   _Jv_JVMTI_ResumeThread,	// ResumeThread
   UNIMPLEMENTED,		// StopThread