Propagate information about text range while creating placeholder text.

Back compatibility with existing plugins shouldn't be broken. [r=den]

platform/lang-api/src/com/intellij/lang/folding/CompositeFoldingBuilder.java

@@ -18,8 +18,9 @@ package com.intellij.lang.folding;
 
 import com.intellij.lang.ASTNode;
 import com.intellij.openapi.editor.Document;
-import com.intellij.openapi.util.Key;
 import com.intellij.openapi.project.DumbAware;
+import com.intellij.openapi.util.Key;
+import com.intellij.openapi.util.TextRange;
 import com.intellij.psi.PsiElement;
 import org.jetbrains.annotations.NotNull;
 
@@ -56,6 +57,14 @@ public class CompositeFoldingBuilder extends FoldingBuilderEx implements DumbAwa
     return descriptors.toArray(new FoldingDescriptor[descriptors.size()]);
   }
 
+    @Override
+  public String getPlaceholderText(@NotNull ASTNode node, @NotNull TextRange range) {
+    final FoldingBuilder builder = node.getUserData(FOLDING_BUILDER);
+    return builder == null ? node.getText() : builder instanceof FoldingBuilderEx
+                                              ? ((FoldingBuilderEx)builder).getPlaceholderText(node, range) : builder.getPlaceholderText(node);
+    }
+
+  @Override
   public String getPlaceholderText(@NotNull ASTNode node) {
     final FoldingBuilder builder = node.getUserData(FOLDING_BUILDER);
     return builder == null ? node.getText() : builder.getPlaceholderText(node);

platform/lang-api/src/com/intellij/lang/folding/FoldingBuilderEx.java

@@ -18,6 +18,7 @@ package com.intellij.lang.folding;
 
 import com.intellij.lang.ASTNode;
 import com.intellij.openapi.editor.Document;
+import com.intellij.openapi.util.TextRange;
 import com.intellij.psi.PsiElement;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
@@ -54,11 +55,15 @@ public abstract class FoldingBuilderEx implements FoldingBuilder {
    * Returns the text which is displayed in the editor for the folding region related to the
    * specified node when the folding region is collapsed.
    *
+   *
    * @param node the node for which the placeholder text is requested.
+   * @param range text range within whole file to fold
    * @return the placeholder text.
    */
   @Nullable
-  public abstract String getPlaceholderText(@NotNull ASTNode node);
+  public String getPlaceholderText(@NotNull ASTNode node, @NotNull TextRange range){
+    return getPlaceholderText(node);
+  }
 
   /**
    * Returns the default collapsed state for the folding region related to the specified node.

platform/lang-api/src/com/intellij/lang/folding/FoldingDescriptor.java

@@ -134,7 +134,9 @@ public class FoldingDescriptor {
     final Language lang = psiElement.getLanguage();
     final FoldingBuilder foldingBuilder = LanguageFolding.INSTANCE.forLanguage(lang);
     if (foldingBuilder != null) {
-      return foldingBuilder.getPlaceholderText(myElement);
+      return foldingBuilder instanceof FoldingBuilderEx
+             ? ((FoldingBuilderEx)foldingBuilder).getPlaceholderText(myElement, myRange)
+             : foldingBuilder.getPlaceholderText(myElement);
     }
     return null;
   }