Concurrency fixes for read shared mode.

jhalliday · Feb 12, 2020 · 576acf7 · 576acf7
1 parent 3b88731
commit 576acf7
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Showing 2 changed files with 22 additions and 7 deletions.
diff --git a/logwriting/src/main/java/com/redhat/mashona/logwriting/MappedFileChannel.java b/logwriting/src/main/java/com/redhat/mashona/logwriting/MappedFileChannel.java
@@ -25,7 +25,7 @@
 import java.nio.channels.*;
 import java.nio.file.Files;
 import java.nio.file.StandardOpenOption;
-import java.util.EnumSet;
+import java.util.*;
 import java.util.concurrent.locks.Lock;
 import java.util.concurrent.locks.ReentrantLock;
 
@@ -310,6 +310,10 @@ public int write(ByteBuffer src, long position) throws IOException {
 
     private int writeInternal(ByteBuffer src, int position) throws ClosedChannelException {
 
+        if(metadata.isReadShared()) {
+            throw new IllegalStateException();
+        }
+
         if (position < metadata.getPersistenceIndex()) {
             throw new IllegalArgumentException();
         }
@@ -324,9 +328,7 @@ private int writeInternal(ByteBuffer src, int position) throws ClosedChannelExce
         dst.put(srcSlice);
         src.position(src.position() + length);
 
-        int startIndex = position;
-
-        persist(startIndex, length);
+        persist(position, length);
 
         return length;
     }
@@ -531,12 +533,16 @@ protected void implCloseChannel() throws IOException {
             // https://bugs.openjdk.java.net/browse/JDK-4724038
             unsafe.invokeCleaner(rawBuffer);
 
-            fileChannel.truncate(metadata.getPersistenceIndex());
-
-            // TODO close metadata (assuming it's private instance)
+            if(!metadata.isReadShared()) {
+                int persistenceIndex = metadata.getPersistenceIndex();
+                logger.trace("truncating {} to {}", file.getAbsolutePath(), persistenceIndex);
+                fileChannel.truncate(persistenceIndex);
+            }
 
             fileChannel.close();
 
+            metadata.close();
+
         } finally {
             lock.unlock();
         }

diff --git a/logwriting/src/main/java/com/redhat/mashona/logwriting/MappedFileChannelMetadata.java b/logwriting/src/main/java/com/redhat/mashona/logwriting/MappedFileChannelMetadata.java
@@ -190,6 +190,15 @@ public void persist(int startIndex, int length) throws ClosedChannelException {
         logger.exit();
     }
 
+    /**
+     * Returns the read sharing mode.
+     *
+     * @return true is read sharing is enabled, false otherwise.
+     */
+    public boolean isReadShared() {
+        return readShared;
+    }
+
     /**
      * Reinitializes the instance.
      *