[JGIT PATCH 12/23] Change ByteArrayWindow to read content outside of WindowCache's lock

From

Shawn O. Pearce <spearce@spearce.org>

Date

Dec 25, 2008, 02:11 UTC

Message-ID

<1230171079-17156-13-git-send-email-spearce@spearce.org>

In-Reply-To

<1230171079-17156-12-git-send-email-spearce@spearce.org>

Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
---
 .../src/org/spearce/jgit/lib/ByteArrayWindow.java  |   17 +++++++++++++++++
 .../src/org/spearce/jgit/lib/WindowCache.java      |    2 +-
 .../src/org/spearce/jgit/lib/WindowedFile.java     |   15 +++++++--------
 3 files changed, 25 insertions(+), 9 deletions(-)

diff --git a/org.spearce.jgit/src/org/spearce/jgit/lib/ByteArrayWindow.java b/org.spearce.jgit/src/org/spearce/jgit/lib/ByteArrayWindow.java
index cea71be..b32d4f8 100644
--- a/org.spearce.jgit/src/org/spearce/jgit/lib/ByteArrayWindow.java
+++ b/org.spearce.jgit/src/org/spearce/jgit/lib/ByteArrayWindow.java
@@ -38,6 +38,8 @@
 
 package org.spearce.jgit.lib;
 
+import java.io.IOException;
+import java.nio.ByteBuffer;
 import java.util.zip.DataFormatException;
 import java.util.zip.Inflater;
 
@@ -45,6 +47,8 @@
  * A {@link ByteWindow} with an underlying byte array for storage.
  */
 final class ByteArrayWindow extends ByteWindow<byte[]> {
+	boolean loaded;
+
 	/**
 	 * Constructor for ByteWindow.
 	 * 
@@ -64,6 +68,7 @@ ByteArrayWindow(final WindowedFile o, final long p, final int d,
 	}
 
 	int copy(final byte[] array, final int p, final byte[] b, final int o, int n) {
+		ensureLoaded(array);
 		n = Math.min(array.length - p, n);
 		System.arraycopy(array, p, b, o, n);
 		return n;
@@ -71,6 +76,7 @@ int copy(final byte[] array, final int p, final byte[] b, final int o, int n) {
 
 	int inflate(final byte[] array, final int pos, final byte[] b, int o,
 			final Inflater inf) throws DataFormatException {
+		ensureLoaded(array);
 		while (!inf.finished()) {
 			if (inf.needsInput()) {
 				inf.setInput(array, pos, array.length - pos);
@@ -82,4 +88,15 @@ int inflate(final byte[] array, final int pos, final byte[] b, int o,
 			o += inf.inflate(b, o, b.length - o);
 		return o;
 	}
+
+	private synchronized void ensureLoaded(final byte[] array) {
+		if (!loaded) {
+			try {
+				provider.fd.getChannel().read(ByteBuffer.wrap(array), start);
+			} catch (IOException e) {
+				throw new RuntimeException("Cannot fault in window", e);
+			}
+			loaded = true;
+		}
+	}
 }
\ No newline at end of file
diff --git a/org.spearce.jgit/src/org/spearce/jgit/lib/WindowCache.java b/org.spearce.jgit/src/org/spearce/jgit/lib/WindowCache.java
index f478f04..649567b 100644
--- a/org.spearce.jgit/src/org/spearce/jgit/lib/WindowCache.java
+++ b/org.spearce.jgit/src/org/spearce/jgit/lib/WindowCache.java
@@ -270,7 +270,7 @@ public static synchronized final void get(final WindowCursor curs,
 		releaseMemory();
 		runClearedWindowQueue();
 
-		wp.loadWindow(curs, id, id << windowSizeShift, wsz);
+		wp.allocWindow(curs, id, id << windowSizeShift, wsz);
 		final ByteWindow<?> e = curs.window;
 		e.chainNext = cache[idx];
 		cache[idx] = e;
diff --git a/org.spearce.jgit/src/org/spearce/jgit/lib/WindowedFile.java b/org.spearce.jgit/src/org/spearce/jgit/lib/WindowedFile.java
index 9c5cf1e..7626693 100644
--- a/org.spearce.jgit/src/org/spearce/jgit/lib/WindowedFile.java
+++ b/org.spearce.jgit/src/org/spearce/jgit/lib/WindowedFile.java
@@ -73,7 +73,7 @@
 
 	final int hash;
 
-	private RandomAccessFile fd;
+	RandomAccessFile fd;
 
 	private long length;
 
@@ -298,8 +298,8 @@ void cacheClose() {
 		fd = null;
 	}
 
-	void loadWindow(final WindowCursor curs, final int windowId,
-			final long pos, final int size) throws IOException {
+	void allocWindow(final WindowCursor curs, final int windowId,
+			final long pos, final int size) {
 		if (WindowCache.mmap) {
 			MappedByteBuffer map;
 			try {
@@ -323,7 +323,10 @@ void loadWindow(final WindowCursor curs, final int windowId,
 			if (map != null) {
 				if (map.hasArray()) {
 					final byte[] b = map.array();
-					curs.window = new ByteArrayWindow(this, pos, windowId, b);
+					final ByteArrayWindow w;
+					w = new ByteArrayWindow(this, pos, windowId, b);
+					w.loaded = true;
+					curs.window = w;
 					curs.handle = b;
 				} else {
 					curs.window = new ByteBufferWindow(this, pos, windowId, map);
@@ -334,10 +337,6 @@ void loadWindow(final WindowCursor curs, final int windowId,
 		}
 
 		final byte[] b = new byte[size];
-		synchronized (fd) {
-			fd.seek(pos);
-			fd.readFully(b);
-		}
 		curs.window = new ByteArrayWindow(this, pos, windowId, b);
 		curs.handle = b;
 	}

-- 
1.6.1.rc4.301.g5497a