Implement skin inheritance via <% .extends skinname %>. Lookup code is now incredibly convoluted for what it does and needs some streamlining.

src/helma/framework/core/Prototype.java

@@ -341,19 +341,25 @@ public final class Prototype {
             skin = Skin.getSkin(res, app);
             if (skin.hasMainskin())
                 break;
+            String extendz = skin.getExtends();
+            if (extendz != null && extendz != skinName)
+                return getSkin(extendz, null, null);
             res = res.getOverloadedResource();
         }
         if (parentName != null) {
             Skin parentSkin = null;
-            Resource parent = skinMap.getResource(parentName);
+            Resource parentResource = skinMap.getResource(parentName);
-            while (parent != null) {
+            while (parentResource != null) {
-                parentSkin = Skin.getSkin(parent, app);
+                parentSkin = Skin.getSkin(parentResource, app);
                 if (parentSkin.hasSubskin(subName))
                     break;
-                parent = parent.getOverloadedResource();
+                String extendz = parentSkin.getExtends();
+                if (extendz != null && extendz != parentName)
+                    return getSkin(extendz, extendz, subName);
+                parentResource = parentResource.getOverloadedResource();
             }
-            if (parent != null) {
+            if (parentResource != null) {
-                if (res != null && app.getResourceComparator().compare(res, parent) > 0)
+                if (res != null && app.getResourceComparator().compare(res, parentResource) > 0)
                     return skin;
                 else
                     return parentSkin.getSubskin(subName);

src/helma/framework/core/Skin.java

@@ -42,6 +42,8 @@ public final class Skin {
     private HashSet sandbox;
     private HashMap subskins;
     private Skin parentSkin = this;
+    private String extendz = null;
+    private boolean hasContent = false;
 
     static private final int PARSE_MACRONAME = 0;
     static private final int PARSE_PARAM = 1;
@@ -157,10 +159,16 @@ public final class Skin {
                     length = i;
                     break;
                 } else {
+                    if (!macro.isCommentMacro) {
+                        hasContent = true;
+                    }
                     partBuffer.add(macro);
                 }
                 i = macro.end - 1;
             } else {
+                if (!hasContent && !Character.isWhitespace(source[i])){
+                    hasContent = true;
+                }
                 escape = source[i] == '\\' && !escape;
             }
         }
@@ -181,7 +189,7 @@ public final class Skin {
      * @return true if this skin contains a main skin
      */
     public boolean hasMainskin() {
-        return length - offset > 0 || subskins == null;
+        return hasContent;
     }
 
     /**
@@ -212,6 +220,10 @@ public final class Skin {
                 (String[]) subskins.keySet().toArray(new String[0]);
     }
 
+    public String getExtends() {
+        return extendz;
+    }
+
     /**
      * Get the raw source text this skin was parsed from
      */
@@ -328,8 +340,6 @@ public final class Skin {
         }
     }
 
-
-
     class Macro {
         final int start, end;
         String name;
@@ -389,6 +399,18 @@ public final class Skin {
                     handlerType = HANDLER_PARAM;
                 }
             }
+
+            if (".extends".equals(name)) {
+                if (parentSkin != Skin.this) {
+                    throw new RuntimeException("Found .extends in subskin");
+                }
+                if (positionalParams == null || positionalParams.size() < 1
+                        || !(positionalParams.get(0) instanceof String)) {
+                    throw new RuntimeException(".extends requires an unnamed string parameter");
+                }
+                extendz = (String) positionalParams.get(0);
+                isCommentMacro = true; // don't render
+            }
         }
 
         private int parse(int macroOffset, boolean lenient) {

src/helma/framework/core/SkinManager.java

@@ -51,7 +51,7 @@ public final class SkinManager implements FilenameFilter {
         Skin skin;
         Prototype proto = prototype;
 
-        // if name contains dot, this might be a substring of some other string
+        // if name contains #, this may be a subskin of some other skin
         String parentName = null, subskinName = null;
         int hash = skinname.indexOf('#');
         if (hash > -1) {
@@ -65,15 +65,27 @@ public final class SkinManager implements FilenameFilter {
             if (skinpath != null) {
                 for (int i = 0; i < skinpath.length; i++) {
                     skin = getSkinInPath(skinpath[i], proto.getName(), skinname);
-                    if (skin != null && skin.hasMainskin()) {
+                    if (skin != null) {
                         // check if skin skin contains main skin
-                        return skin;
+                        if (skin.hasMainskin()) {
+                            return skin;
+                        }
+                        String extendz = skin.getExtends();
+                        if (extendz != null && !extendz.equals(skinname)) {
+                            return getSkin(prototype, extendz, skinpath);
+                        }
                     } else if (parentName != null) {
                         // get parent skin
                         skin = getSkinInPath(skinpath[i], proto.getName(), parentName);
                         // check if it contains subskin
-                        if (skin != null && skin.hasSubskin(subskinName)) {
+                        if (skin != null) {
-                            return skin.getSubskin(subskinName);
+                            if (skin.hasSubskin(subskinName)) {
+                                return skin.getSubskin(subskinName);
+                            }
+                            String extendz = skin.getExtends();
+                            if (extendz != null && !extendz.equals(skinname)) {
+                                return getSkin(prototype, extendz + "#" + subskinName, skinpath);
+                            }
                         }
                     }
                 }