Shucks, that was a lot more complicated than I thought

The mod time of a target directory can't be reliably checked using the files, so we need to compare
the modificaiton times of each source and destination image file as we go.

tools/src/main/java/com/threerings/media/tile/bundle/tools/BundleWriter.java

@@ -77,24 +77,29 @@ public class BundleWriter
     }
 
     /**
-     * Tests if the target is newer than the given time. Note that if we are in directory-mode,
+     * Tests if the target bundle is newer than the given time. Note that if we are in
-     * false is returned.
+     * directory-mode, false is returned.
      */
     public boolean isNewerThan (long newest)
     {
         if (_jar != null) {
             return _target.lastModified() > newest;
         } else {
-            File []files = _target.listFiles();
-            if (files == null) {
-                return false;
-            }
-            for (File file : files) {
-                if (file.lastModified() < newest) {
             return false;
         }
     }
-            return true;
+
+    /**
+     * Tests if a given path within the target bundle is newer than a given time. Note that if
+     * we are in jar mode, false is returned.
+     */
+    public boolean isPathNewerThan (String path, long newest)
+    {
+        if (_jar != null) {
+            return false;
+        } else {
+            File f = new File(_target, path);
+            return f.lastModified() > newest;
         }
     }
 

tools/src/main/java/com/threerings/media/tile/bundle/tools/TileSetBundler.java

@@ -43,6 +43,7 @@ import org.xml.sax.SAXException;
 import com.samskivert.io.PersistenceException;
 import com.samskivert.io.StreamUtil;
 import com.samskivert.util.HashIntMap;
+import com.samskivert.util.IntMap;
 
 import com.threerings.resource.FastImageIO;
 
@@ -131,6 +132,9 @@ public class TileSetBundler
         /** Loads images for the bundle. */
         public final ImageProvider improv;
 
+        /** Modification time of the newest source file. */
+        public final long newestSource;
+
         /**
          * Creates a new writer.
          *
@@ -138,11 +142,13 @@ public class TileSetBundler
          * @param bundle contains the tilesets we'd like to save out to the bundle.
          * @param improv the image provider.
          */
-        public Writer (BundleWriter bwriter, TileSetBundle bundle, ImageProvider improv)
+        public Writer (BundleWriter bwriter, TileSetBundle bundle, ImageProvider improv,
+            long newestSource)
         {
             this.bundle = bundle;
             this.bwriter = bwriter;
             this.improv = improv;
+            this.newestSource = newestSource;
         }
 
         /**
@@ -399,7 +405,7 @@ public class TileSetBundler
             }
         };
 
-        return new Writer(target, bundle, improv).imageBase(bundleDesc.getParent());
+        return new Writer(target, bundle, improv, newest).imageBase(bundleDesc.getParent());
     }
 
     /**
@@ -417,7 +423,29 @@ public class TileSetBundler
             // bundle till we're done iterating.
             HashIntMap<TileSet> toUpdate = new HashIntMap<TileSet>();
             while (iditer.hasNext()) {
-                int tileSetId = iditer.next().intValue();
+                processBundleImage(iditer.next().intValue(), target, toUpdate);
+            }
+            target.bundle.putAll(toUpdate);
+
+            writeUpdatedBundle(target);
+
+            // finally close up the jar file and call ourself done
+            target.bwriter.close();
+
+        } catch (Exception e) {
+            // remove the incomplete jar file and rethrow the exception
+            target.bwriter.close();
+            if (!target.bwriter.delete()) {
+                log.warning("Failed to close botched bundle '" + target + "'.");
+            }
+            String errmsg = "Failed to create bundle " + target + ": " + e;
+            throw (IOException) new IOException(errmsg).initCause(e);
+        }
+    }
+
+    protected static void processBundleImage (
+        int tileSetId, Writer target, IntMap<TileSet> toUpdate) throws IOException
+    {
         TileSet set = target.bundle.getTileSet(tileSetId);
         String imagePath = set.getImagePath();
 
@@ -425,21 +453,29 @@ public class TileSetBundler
         if (imagePath == null) {
             log.warning("Tileset contains no image path " +
                         "[set=" + set + "]. It ain't gonna work.");
-                    continue;
+            return;
         }
 
+        File ifile = new File(target.imageBase, imagePath);
+        long sourceTime = Math.max(target.newestSource, ifile.lastModified());
+
         // if this is an object tileset, trim it
         if (target.trim && (set instanceof ObjectTileSet)) {
-                    // set the tileset up with an image provider; we
-                    // need to do this so that we can trim it!
-                    set.setImageProvider(target.improv);
-
             // add .raw if requested
             if (target.raw) {
                 imagePath = adjustImagePath(imagePath);
             }
+
+            if (target.bwriter.isPathNewerThan(imagePath, sourceTime)) {
+                return;
+            }
+
             OutputStream dest = target.bwriter.startNewFile(imagePath);
 
+            // set the tileset up with an image provider; we
+            // need to do this so that we can trim it!
+            set.setImageProvider(target.improv);
+
             try {
                 // create a trimmed object tileset, which will
                 // write the trimmed tileset image to the target file
@@ -462,22 +498,22 @@ public class TileSetBundler
         } else {
             // read the image file and convert it to our custom
             // format in the bundle
-                    File ifile = new File(target.imageBase, imagePath);
             try {
                 BufferedImage image = ImageIO.read(ifile);
                 if (target.raw && FastImageIO.canWrite(image)) {
                     imagePath = adjustImagePath(imagePath);
-                            // NOTE: DirectoryTileSetBundler used to check the modification time
+                    if (!target.bwriter.isPathNewerThan(imagePath, sourceTime)) {
-                            // of the target image here. There may be something to it, but it
-                            // looked unnecessary
                         OutputStream dest = target.bwriter.startNewFile(imagePath);
                         set.setImagePath(imagePath);
                         FastImageIO.write(image, dest);
+                    }
                 } else {
+                    if (!target.bwriter.isPathNewerThan(imagePath, sourceTime)) {
                         OutputStream dest = target.bwriter.startNewFile(imagePath);
                         FileInputStream imgin = new FileInputStream(ifile);
                         StreamUtil.copy(imgin, dest);
                     }
+                }
             } catch (Exception e) {
                 String msg = "Failure bundling image " + ifile +
                     ": " + e;
@@ -485,7 +521,16 @@ public class TileSetBundler
             }
         }
     }
-            target.bundle.putAll(toUpdate);
+
+    protected static void writeUpdatedBundle (Writer target)
+        throws IOException
+    {
+        String meta = target.json != null ?
+            BundleUtil.METADATA_JSON_PATH : BundleUtil.METADATA_PATH;
+
+        if (target.bwriter.isPathNewerThan(meta, target.newestSource)) {
+            return;
+        }
 
         // now write a serialized representation of the tileset bundle
         if (target.json != null) {
@@ -499,30 +544,17 @@ public class TileSetBundler
                 array.add(tset);
             }
 
-                // now write a serialized representation of the tileset bundle
+            OutputStream fout = target.bwriter.startNewFile(meta);
-                OutputStream fout = target.bwriter.startNewFile(BundleUtil.METADATA_JSON_PATH);
             fout.write(array.toString().getBytes());
             fout.close();
+
         } else {
-                // object to the bundle jar file
             ObjectOutputStream oout = new ObjectOutputStream(
                 target.bwriter.startNewFile(BundleUtil.METADATA_PATH));
             oout.writeObject(target.bundle);
             oout.flush();
         }
 
-            // finally close up the jar file and call ourself done
-            target.bwriter.close();
-
-        } catch (Exception e) {
-            // remove the incomplete jar file and rethrow the exception
-            target.bwriter.close();
-            if (!target.bwriter.delete()) {
-                log.warning("Failed to close botched bundle '" + target + "'.");
-            }
-            String errmsg = "Failed to create bundle " + target + ": " + e;
-            throw (IOException) new IOException(errmsg).initCause(e);
-        }
     }
 
     /** Replaces the image suffix with <code>.raw</code>. */