optimize dependset by not comparing each target with each source but

only the oldest target.

Submitted by:	mrezaei@starpoint.com

I've also swapped the order of handling sourcefilesets and
sourcefilelists as filelists are a lot less expensive than filesets.


git-svn-id: https://svn.apache.org/repos/asf/ant/core/trunk@271455 13f79535-47bb-0310-9956-ffa450edef68

src/main/org/apache/tools/ant/taskdefs/DependSet.java

@@ -1,7 +1,7 @@
 /*
  * The Apache Software License, Version 1.1
  *
- * Copyright (c) 2001 The Apache Software Foundation.  All rights
+ * Copyright (c) 2001-2002 The Apache Software Foundation.  All rights
  * reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -179,6 +179,8 @@ public class DependSet extends MatchingTask {
         // Grab all the target files specified via filesets
         //
         Vector  allTargets         = new Vector();
+        long oldestTargetTime = 0;
+        File oldestTarget = null;
         Enumeration enumTargetSets = targetFileSets.elements();
         while (enumTargetSets.hasMoreElements()) {
                  
@@ -195,6 +197,12 @@ public class DependSet extends MatchingTask {
                  log("Warning: "+targetFiles[i]+" modified in the future.", 
                      Project.MSG_WARN);
               }
+
+              if (oldestTarget == null ||
+                  dest.lastModified() < oldestTargetTime) {
+                  oldestTargetTime = dest.lastModified();
+                  oldestTarget = dest;
+              }
            }
         }
 
@@ -223,81 +231,80 @@ public class DependSet extends MatchingTask {
                  log("Warning: "+targetFiles[i]+" modified in the future.", 
                      Project.MSG_WARN);
               }
+              if (oldestTarget == null ||
+                  dest.lastModified() < oldestTargetTime) {
+                  oldestTargetTime = dest.lastModified();
+                  oldestTarget = dest;
+              }
            }
         }
+        if (oldestTarget != null) {
+            log(oldestTarget + " is oldest target file", Project.MSG_VERBOSE);
+        } else { 
+            // no target files, then we cannot remove any target files and
+            // skip the following tests right away
+            upToDate = false;
+        }
 
         //
-        // Check targets vs source files specified via filesets
+        // Check targets vs source files specified via filelists
         //
         if (upToDate) {
-           Enumeration enumSourceSets = sourceFileSets.elements();
-           while (upToDate && enumSourceSets.hasMoreElements()) {
+           Enumeration enumSourceLists = sourceFileLists.elements();
+           while (upToDate && enumSourceLists.hasMoreElements()) {
           
-              FileSet sourceFS          = (FileSet) enumSourceSets.nextElement();
-              DirectoryScanner sourceDS = sourceFS.getDirectoryScanner(project);
-              String[] sourceFiles      = sourceDS.getIncludedFiles();
+              FileList sourceFL         = (FileList) enumSourceLists.nextElement();
+              String[] sourceFiles      = sourceFL.getFiles(project);
 
-              for (int i=0; upToDate && i < sourceFiles.length; i++) {
-                 File src = new File(sourceFS.getDir(project), sourceFiles[i]);
+              int i = 0;
+              do {
+                 File src = new File(sourceFL.getDir(project), sourceFiles[i]);
 
                  if (src.lastModified() > now) {
                     log("Warning: "+sourceFiles[i]+" modified in the future.", 
                         Project.MSG_WARN);
                  }
 
-                 Enumeration enumTargets = allTargets.elements();
-                 while (upToDate && enumTargets.hasMoreElements()) {
-                 
-                    File dest = (File)enumTargets.nextElement();
-                    if (src.lastModified() > dest.lastModified()) {
-                       log(dest.getPath() + " is out of date with respect to " +
-                                sourceFiles[i], Project.MSG_VERBOSE);
-                       upToDate = false;
+                 if (!src.exists()) {
+                    log(sourceFiles[i]+ " does not exist.", Project.MSG_VERBOSE);
+                    upToDate = false;
+                    break;
+                 }
 
-                    }
+                 if (src.lastModified() > oldestTargetTime) {
+                    upToDate = false;
+                    log(oldestTarget + " is out of date with respect to " +
+                        sourceFiles[i], Project.MSG_VERBOSE);
                  }
-              }
+              } while (upToDate && (++i < sourceFiles.length) );
            }
         }
 
         //
-        // Check targets vs source files specified via filelists
+        // Check targets vs source files specified via filesets
         //
         if (upToDate) {
-           Enumeration enumSourceLists = sourceFileLists.elements();
-           while (upToDate && enumSourceLists.hasMoreElements()) {
+           Enumeration enumSourceSets = sourceFileSets.elements();
+           while (upToDate && enumSourceSets.hasMoreElements()) {
           
-              FileList sourceFL         = (FileList) enumSourceLists.nextElement();
-              String[] sourceFiles      = sourceFL.getFiles(project);
+              FileSet sourceFS          = (FileSet) enumSourceSets.nextElement();
+              DirectoryScanner sourceDS = sourceFS.getDirectoryScanner(project);
+              String[] sourceFiles      = sourceDS.getIncludedFiles();
 
-              int i = 0;
-              do {
-                 File src = new File(sourceFL.getDir(project), sourceFiles[i]);
+              for (int i=0; upToDate && i < sourceFiles.length; i++) {
+                 File src = new File(sourceFS.getDir(project), sourceFiles[i]);
 
                  if (src.lastModified() > now) {
                     log("Warning: "+sourceFiles[i]+" modified in the future.", 
                         Project.MSG_WARN);
                  }
 
-                 if (!src.exists()) {
-                    log(sourceFiles[i]+ " does not exist.", Project.MSG_VERBOSE);
+                 if (src.lastModified() > oldestTargetTime) {
                     upToDate = false;
-                    break;
+                    log(oldestTarget + " is out of date with respect to " +
+                        sourceFiles[i], Project.MSG_VERBOSE);
                  }
-
-                 Enumeration enumTargets = allTargets.elements();
-                 while (upToDate && enumTargets.hasMoreElements()) {
-                 
-                    File dest = (File)enumTargets.nextElement();
-                    
-                    if (src.lastModified() > dest.lastModified()) {
-                       log(dest.getPath() + " is out of date with respect to " +
-                                sourceFiles[i], Project.MSG_VERBOSE);
-                       upToDate = false;
-
-                    }
-                 }
-              } while (upToDate && (++i < sourceFiles.length) );
+              }
            }
         }