Mercurial > hg > release > icedtea7-forest-2.4 > jdk

changeset 6333:98ad2f1e25d1

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8009063: Improve reliability of ConcurrentHashMap Reviewed-by: alanb, ahgross
author chegar
date Sun, 03 Mar 2013 10:11:45 +0000
parents 17ac71e7b720
children c2fff439d91a
files src/share/classes/java/util/concurrent/ConcurrentHashMap.java
diffstat 1 files changed, 27 insertions(+), 1 deletions(-) [+]
line wrap: on
line diff
--- a/src/share/classes/java/util/concurrent/ConcurrentHashMap.java	Tue Mar 05 16:46:10 2013 -0800
+++ b/src/share/classes/java/util/concurrent/ConcurrentHashMap.java	Sun Mar 03 10:11:45 2013 +0000
@@ -40,6 +40,7 @@
 import java.io.IOException;
 import java.io.ObjectInputStream;
 import java.io.ObjectOutputStream;
+import java.io.ObjectStreamField;
 
 /**
  * A hash table supporting full concurrency of retrievals and
@@ -1535,7 +1536,23 @@
     @SuppressWarnings("unchecked")
     private void readObject(java.io.ObjectInputStream s)
         throws IOException, ClassNotFoundException {
-        s.defaultReadObject();
+        // Don't call defaultReadObject()
+        ObjectInputStream.GetField oisFields = s.readFields();
+        final Segment<K,V>[] oisSegments = (Segment<K,V>[])oisFields.get("segments", null);
+
+        final int ssize = oisSegments.length;
+        if (ssize < 1 || ssize > MAX_SEGMENTS
+            || (ssize & (ssize-1)) != 0 )  // ssize not power of two
+            throw new java.io.InvalidObjectException("Bad number of segments:"
+                                                     + ssize);
+        int sshift = 0, ssizeTmp = ssize;
+        while (ssizeTmp > 1) {
+            ++sshift;
+            ssizeTmp >>>= 1;
+        }
+        UNSAFE.putIntVolatile(this, SEGSHIFT_OFFSET, 32 - sshift);
+        UNSAFE.putIntVolatile(this, SEGMASK_OFFSET, ssize - 1);
+        UNSAFE.putObjectVolatile(this, SEGMENTS_OFFSET, oisSegments);
 
         // set hashMask
         UNSAFE.putIntVolatile(this, HASHSEED_OFFSET, randomHashSeed(this));
@@ -1568,6 +1585,9 @@
     private static final long TBASE;
     private static final int TSHIFT;
     private static final long HASHSEED_OFFSET;
+    private static final long SEGSHIFT_OFFSET;
+    private static final long SEGMASK_OFFSET;
+    private static final long SEGMENTS_OFFSET;
 
     static {
         int ss, ts;
@@ -1581,6 +1601,12 @@
             ss = UNSAFE.arrayIndexScale(sc);
             HASHSEED_OFFSET = UNSAFE.objectFieldOffset(
                 ConcurrentHashMap.class.getDeclaredField("hashSeed"));
+            SEGSHIFT_OFFSET = UNSAFE.objectFieldOffset(
+                ConcurrentHashMap.class.getDeclaredField("segmentShift"));
+            SEGMASK_OFFSET = UNSAFE.objectFieldOffset(
+                ConcurrentHashMap.class.getDeclaredField("segmentMask"));
+            SEGMENTS_OFFSET = UNSAFE.objectFieldOffset(
+                ConcurrentHashMap.class.getDeclaredField("segments"));
         } catch (Exception e) {
             throw new Error(e);
         }