--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/agent/src/share/classes/sun/jvm/hotspot/runtime/JNIHandleBlock.java	Sat Dec 01 00:00:00 2007 +0000
@@ -0,0 +1,154 @@
+/*
+ * Copyright 2000-2001 Sun Microsystems, Inc.  All Rights Reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code 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
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ *
+ */
+
+package sun.jvm.hotspot.runtime;
+
+import java.util.*;
+import sun.jvm.hotspot.debugger.*;
+import sun.jvm.hotspot.runtime.*;
+import sun.jvm.hotspot.types.*;
+import sun.jvm.hotspot.utilities.*;
+
+/** */
+public class JNIHandleBlock extends VMObject {
+  private static Field         handlesField;
+  private static CIntegerField topField;
+  private static AddressField  nextField;
+
+  private static int           blockSizeInOops;
+
+  static {
+    VM.registerVMInitializedObserver(new Observer() {
+        public void update(Observable o, Object data) {
+          initialize(VM.getVM().getTypeDataBase());
+        }
+      });
+  }
+
+  private static synchronized void initialize(TypeDataBase db) {
+    Type type = db.lookupType("JNIHandleBlock");
+
+    handlesField = type.getField("_handles");
+    topField = type.getCIntegerField("_top");
+    nextField = type.getAddressField("_next");
+
+    blockSizeInOops = db.lookupIntConstant("JNIHandleBlock::block_size_in_oops").intValue();
+  }
+
+  public JNIHandleBlock(Address addr) {
+    super(addr);
+  }
+
+  public JNIHandleBlock next() {
+    Address handleAddr = nextField.getValue(addr);
+    if (handleAddr == null) {
+      return null;
+    }
+
+    /* the next handle block is valid only if the current block is full */
+    if (top() < blockSizeInOops) {
+      return null;
+    }
+    return new JNIHandleBlock(handleAddr);
+  }
+
+  public int top() {
+    return (int) topField.getValue(addr);
+  }
+
+  public void oopsDo(AddressVisitor visitor) {
+    // Visit handles in this block
+    for (int i = 0; i < top(); i++) {
+      Address cur = getOopHandleAddress(i);
+      if (cur != null) {
+        visitor.visitAddress(cur);
+      }
+    }
+
+    // Visit handles in subsequent blocks if necessary
+    JNIHandleBlock n = next();
+    if (n != null) {
+      n.oopsDo(visitor);
+    }
+  }
+
+  public OopHandle getOopHandle(int x) {
+    Address oopAddr = getOopHandleAddress(x);
+    if (oopAddr != null) {
+      return oopAddr.getOopHandleAt(0);
+    }
+    return null;
+  }
+
+  /** Debugging routine only. Returns non-null JNIHandleBlock
+      containing the JNI handle or null if this handle block and its
+      successors did not contain it (or if the handle was deleted). */
+  public JNIHandleBlock blockContainingHandle(Address jniHandle) {
+    JNIHandleBlock cur = this;
+    while (cur != null) {
+      if (indexOfHandle(jniHandle) >= 0) {
+        return cur;
+      }
+      cur = cur.next();
+    }
+    return null;
+  }
+
+  /** Debugging routine: returns the index (0..top() - 1) of the
+      handle in this block, or -1 if the handle was not contained in
+      this block. Does not search successor blocks. */
+  public int indexOfHandle(Address jniHandle) {
+    for (int i = 0; i < top(); i++) {
+      Address addr = getOopHandleAddress(i);
+      if (addr != null) {
+        if (addr.equals(jniHandle)) {
+          return i;
+        }
+      }
+    }
+    return -1;
+  }
+
+  public String toString() {
+    Address handleBase = addr.addOffsetTo(handlesField.getOffset());
+    Address handleEnd = addr.addOffsetTo(handlesField.getOffset() + top() * VM.getVM().getOopSize());
+    return "JNIHandleBlock [" + handleBase + ", " + handleEnd + ")";
+  }
+
+  /** Only returns addresses of valid OopHandles */
+  private Address getOopHandleAddress(int x) {
+    if (Assert.ASSERTS_ENABLED) {
+      Assert.that(x < top(), "out of bounds");
+    }
+
+    Address oopAddr = addr.addOffsetTo(handlesField.getOffset() + x * VM.getVM().getOopSize());
+    OopHandle handle = oopAddr.getOopHandleAt(0);
+    if (VM.getVM().getUniverse().isInReserved(handle) && !VM.getVM().getJNIHandles().isDeletedHandle(handle)) {
+      /* the oop handle is valid only if it is not freed (i.e. reserved in heap) and is not a deleted oop */
+      return oopAddr;
+    } else {
+      return null;
+    }
+  }
+}