From 9dabf2fc594d583da597dd6fbba7b4ba1d13e241 Mon Sep 17 00:00:00 2001
From: "Shawn O. Pearce" <spearce@spearce.org>
Date: Sat, 2 Dec 2006 23:12:25 -0500
Subject: [PATCH] Use an array for our packs rather than a List.

Since we need to traverse the set of available packs for every object
access this is really in our critical path.  Using an array here is
slightly faster as we don't have method invocation overheads or any
downcasting to deal with.

Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
---
 .../src/org/spearce/jgit/lib/Repository.java       | 62 +++++++++-------------
 1 file changed, 25 insertions(+), 37 deletions(-)

diff --git a/org.spearce.jgit/src/org/spearce/jgit/lib/Repository.java b/org.spearce.jgit/src/org/spearce/jgit/lib/Repository.java
index 89fbef5d..d84da318 100644
--- a/org.spearce.jgit/src/org/spearce/jgit/lib/Repository.java
+++ b/org.spearce.jgit/src/org/spearce/jgit/lib/Repository.java
@@ -24,8 +24,6 @@ import java.io.FileReader;
 import java.io.FileWriter;
 import java.io.IOException;
 import java.util.ArrayList;
-import java.util.Iterator;
-import java.util.List;
 
 import org.spearce.jgit.errors.IncorrectObjectTypeException;
 import org.spearce.jgit.errors.ObjectWritingException;
@@ -40,17 +38,17 @@ public class Repository {
 
     private final File refsDir;
 
-    private final List packs;
-
     private final RepositoryConfig config;
 
+    private PackFile[] packs;
+
     private WindowCache windows;
 
     public Repository(final File d) throws IOException {
 	gitDir = d.getAbsoluteFile();
 	objectsDir = new File(gitDir, "objects");
 	refsDir = new File(gitDir, "refs");
-	packs = new ArrayList();
+	packs = new PackFile[0];
 	config = new RepositoryConfig(this);
 	if (objectsDir.exists()) {
 	    getConfig().load();
@@ -117,11 +115,9 @@ public class Repository {
     }
 
     public boolean hasObject(final ObjectId objectId) {
-	final Iterator i = packs.iterator();
-	while (i.hasNext()) {
-	    final PackFile p = (PackFile) i.next();
+	for (int k = packs.length - 1; k >= 0; k--) {
 	    try {
-		if (p.hasObject(objectId))
+		if (packs[k].hasObject(objectId))
 		    return true;
 	    } catch (IOException ioe) {
 		// This shouldn't happen unless the pack was corrupted
@@ -134,9 +130,18 @@ public class Repository {
     }
 
     public ObjectLoader openObject(final ObjectId id) throws IOException {
-	final ObjectLoader packed = objectInPack(id);
-	if (packed != null)
-	    return packed;
+	for (int k = packs.length - 1; k >= 0; k--) {
+	    try {
+		final ObjectLoader o = packs[k].get(id);
+		if (o != null)
+		    return o;
+	    } catch (IOException ioe) {
+		// This shouldn't happen unless the pack was corrupted after we
+		// opened it. We'll ignore the error as though the object does
+		// not exist in this pack.
+		//
+	    }
+	}
 	try {
 	    return new UnpackedObjectLoader(this, id);
 	} catch (FileNotFoundException fnfe) {
@@ -211,12 +216,10 @@ public class Repository {
     }
 
     public void closePacks() throws IOException {
-	final Iterator i = packs.iterator();
-	while (i.hasNext()) {
-	    final PackFile pr = (PackFile) i.next();
-	    pr.close();
+	for (int k = packs.length - 1; k >= 0; k--) {
+	    packs[k].close();
 	}
-	packs.clear();
+	packs = new PackFile[0];
     }
 
     public void scanForPacks() {
@@ -233,33 +236,18 @@ public class Repository {
 			&& idx.canRead();
 	    }
 	});
+	final ArrayList p = new ArrayList(list.length);
 	for (int k = 0; k < list.length; k++) {
 	    try {
-		packs.add(new PackFile(this, list[k]));
+		p.add(new PackFile(this, list[k]));
 	    } catch (IOException ioe) {
 		// Whoops. That's not a pack!
 		//
 	    }
 	}
-    }
-
-    private ObjectLoader objectInPack(final ObjectId objectId) {
-	final Iterator i = packs.iterator();
-	while (i.hasNext()) {
-	    final PackFile p = (PackFile) i.next();
-	    try {
-		final ObjectLoader o = p.get(objectId);
-		if (o != null) {
-		    return o;
-		}
-	    } catch (IOException ioe) {
-		// This shouldn't happen unless the pack was corrupted after we
-		// opened it. We'll ignore the error as though the object does
-		// not exist in this pack.
-		//
-	    }
-	}
-	return null;
+	final PackFile[] arr = new PackFile[p.size()];
+	p.toArray(arr);
+	packs = arr;
     }
 
     private void writeSymref(final String name, final String target)
-- 
2.11.4.GIT