From 4ecea70e9b75546d922e43fde8f61550094119ee Mon Sep 17 00:00:00 2001
From: Stefan Bodewig <bodewig@apache.org>
Date: Wed, 17 Sep 2008 16:12:53 +0000
Subject: [PATCH] Bring back memoization of File.list

git-svn-id: https://svn.apache.org/repos/asf/ant/core/trunk@696355 13f79535-47bb-0310-9956-ffa450edef68
---
 .../apache/tools/ant/DirectoryScanner.java    | 15 ++++++++++--
 .../ant/types/selectors/TokenizedPath.java    | 24 +++++++++++++++----
 2 files changed, 33 insertions(+), 6 deletions(-)

diff --git a/src/main/org/apache/tools/ant/DirectoryScanner.java b/src/main/org/apache/tools/ant/DirectoryScanner.java
index 081f8a081..2bc5382e3 100644
--- a/src/main/org/apache/tools/ant/DirectoryScanner.java
+++ b/src/main/org/apache/tools/ant/DirectoryScanner.java
@@ -286,6 +286,11 @@ public class DirectoryScanner
      */
     private Map fileListMap = new HashMap();
 
+    /**
+     * Uses fileListMap to cache directory listings.
+     */
+    private final TokenizedPath.FileLister fileLister = new CachedFileLister();
+
     /**
      * List of all scanned directories.
      *
@@ -957,7 +962,8 @@ public class DirectoryScanner
                             : FILE_UTILS.removeLeadingPath(canonBase,
                                          getCanonicalFile(myfile));
                         if (!path.equals(currentelement) || ON_VMS) {
-                            myfile = currentPath.findFile(basedir, true);
+                            myfile = currentPath.findFile(basedir, true,
+                                                          fileLister);
                             if (myfile != null && basedir != null) {
                                 currentelement = FILE_UTILS.removeLeadingPath(
                                     basedir, myfile);
@@ -974,7 +980,7 @@ public class DirectoryScanner
                 }
 
                 if ((myfile == null || !myfile.exists()) && !isCaseSensitive()) {
-                    File f = currentPath.findFile(basedir, false);
+                    File f = currentPath.findFile(basedir, false, fileLister);
                     if (f != null && f.exists()) {
                         // adapt currentelement to the case we've
                         // actually found
@@ -1896,4 +1902,9 @@ public class DirectoryScanner
         return new File(getCanonicalPath(file));
     }
 
+    private class CachedFileLister implements TokenizedPath.FileLister {
+        public String[] list(File f) {
+            return DirectoryScanner.this.list(f);
+        }
+    }
 }
diff --git a/src/main/org/apache/tools/ant/types/selectors/TokenizedPath.java b/src/main/org/apache/tools/ant/types/selectors/TokenizedPath.java
index aecd55da8..4e222b1e5 100644
--- a/src/main/org/apache/tools/ant/types/selectors/TokenizedPath.java
+++ b/src/main/org/apache/tools/ant/types/selectors/TokenizedPath.java
@@ -105,7 +105,7 @@ public class TokenizedPath {
      * @param cs whether to scan case-sensitively.
      * @return File object that points to the file in question or null.
      */
-    public File findFile(File base, final boolean cs) {
+    public File findFile(File base, final boolean cs, FileLister fileLister) {
         String[] tokens = tokenizedPath;
         if (FileUtils.isAbsolutePath(path)) {
             if (base == null) {
@@ -123,7 +123,7 @@ public class TokenizedPath {
                 tokens = SelectorUtils.tokenizePathAsArray(s);
             }
         }
-        return findFile(base, tokens, cs);
+        return findFile(base, tokens, cs, fileLister);
     }
 
     /**
@@ -170,12 +170,12 @@ public class TokenizedPath {
      * @return File object that points to the file in question or null.
      */
     private static File findFile(File base, final String[] pathElements,
-                                 final boolean cs) {
+                                 final boolean cs, FileLister fileLister) {
         for (int current = 0; current < pathElements.length; current++) {
             if (!base.isDirectory()) {
                 return null;
             }
-            String[] files = base.list();
+            String[] files = fileLister.list(base);
             if (files == null) {
                 throw new BuildException("IO error scanning directory "
                                          + base.getAbsolutePath());
@@ -206,4 +206,20 @@ public class TokenizedPath {
     public TokenizedPattern toPattern() {
         return new TokenizedPattern(path, tokenizedPath); 
     }
+
+    /**
+     * Helper that obtains the listing of a directory.
+     */
+    public static interface FileLister {
+        String[] list(File file);
+    }
+
+    /**
+     * Default implementation using File.list().
+     */
+    public static final class DefaultLister implements FileLister {
+        public String[] list(File file) {
+            return file.list();
+        }
+    }
 }