Added an ignorecontents attribute to <different>

git-svn-id: https://svn.apache.org/repos/asf/ant/core/trunk@276707 13f79535-47bb-0310-9956-ffa450edef68

WHATSNEW

@@ -37,6 +37,8 @@ Changes that could break older environments:
 Other changes:
 --------------
 
+* New attribute ignorecontents for <different> selector
+
 Fixed bugs:
 -----------
 

docs/manual/CoreTypes/selectors.html

@@ -300,7 +300,8 @@
     <li> Files with different lengths are different.
     <li> If <tt>ignoreFileTimes</tt> is turned off, then differing file
     timestamps will cause files to be regarded as different.
-    <li> Finally a byte-for-byte check is run against the two files
+    <li> Unless<tt>ignoreContents</tt> is set to true, a byte-for-byte check is run
+    against the two files
     </ol>
 
     This is a useful selector to work with programs and tasks that don't handle
@@ -342,6 +343,14 @@
         </td>
         <td valign="top" align="center">No</td>
       </tr>
+      <tr>
+        <td valign="top">ignoreContents</td>
+        <td valign="top">Whether to do a byte per byte compare.
+          Default is false (contents are compared).
+          Since ant 1.6.3
+        </td>
+        <td valign="top" align="center">No</td>
+      </tr>
       <tr>
         <td valign="top">granularity</td>
         <td valign="top">The number of milliseconds leeway to give before

src/main/org/apache/tools/ant/types/selectors/DifferentSelector.java

@@ -25,10 +25,14 @@ import java.io.IOException;
 
 /**
  * This selector selects files against a mapped set of target files, selecting
- * all those files which are different. A byte-by-byte comparision is performed
- * on equal length files; files with different lengths are deemed different
- * automatically; files with identical timestamps are viewed as matching by
+ * all those files which are different.
+ * Files with different lengths are deemed different
+ * automatically
+ * Files with identical timestamps are viewed as matching by
  * default, unless you specify otherwise.
+ * Contents are compared if the lengths are the same
+ * and the timestamps are ignored or the same,
+ * except if you decide to ignore contents to gain speed.
  * <p>
  * This is a useful selector to work with programs and tasks that don't handle
  * dependency checking properly; Even if a predecessor task always creates its
@@ -47,6 +51,7 @@ public class DifferentSelector extends MappingSelector {
     private FileUtils fileUtils = FileUtils.newFileUtils();
 
     private boolean ignoreFileTimes = true;
+    private boolean ignoreContents = false;
 
 
     /**
@@ -56,7 +61,14 @@ public class DifferentSelector extends MappingSelector {
     public void setIgnoreFileTimes(boolean ignoreFileTimes) {
         this.ignoreFileTimes = ignoreFileTimes;
     }
-
+    /**
+     * This flag tells the selector to ignore contents
+     * @param ignoreContents if true ignore contents
+     * @since ant 1.6.3
+     */
+    public void setIgnoreContents(boolean ignoreContents) {
+        this.ignoreContents = ignoreContents;
+    }
     /**
      * this test is our selection test that compared the file with the destfile
      * @param srcfile the source file
@@ -86,13 +98,16 @@ public class DifferentSelector extends MappingSelector {
                 return true;
             }
         }
-
-        //here do a bulk comparison
-        try {
-            return !fileUtils.contentEquals(srcfile, destfile);
-        } catch (IOException e) {
-            throw new BuildException("while comparing " + srcfile + " and "
-                    + destfile, e);
+        if (!ignoreContents) {
+            //here do a bulk comparison
+            try {
+                return !fileUtils.contentEquals(srcfile, destfile);
+            } catch (IOException e) {
+                throw new BuildException("while comparing " + srcfile + " and "
+                        + destfile, e);
+            }
+        } else {
+            return false;
         }
     }
 }