IDEA-93649 Custom regions in XML

platform/core-api/src/com/intellij/lang/folding/CustomFoldingBuilder.java

@@ -32,6 +32,8 @@ import java.util.ArrayList;
 import java.util.List;
 import java.util.Set;
 
+import static com.intellij.lang.folding.CompositeFoldingBuilder.FOLDING_BUILDER;
+
 /**
  * Builds custom folding regions. If custom folding is supported for a language, its FoldingBuilder must be inherited from this class.
  * 
@@ -97,6 +99,8 @@ public abstract class CustomFoldingBuilder extends FoldingBuilderEx implements P
           ASTNode startNode = localFoldingStack.pop();
           int startOffset = startNode.getTextRange().getStartOffset();
           TextRange range = new TextRange(startOffset, child.getTextRange().getEndOffset());
+          startNode.getPsi().putUserData(FOLDING_BUILDER, this); // Required by CompositeFoldingBuilder when getting info from the original
+                                                                 // folding builder
           descriptors.add(new FoldingDescriptor(startNode, range));
           Set<ASTNode> nodeSet = ourCustomRegionElements.get();
           nodeSet.add(startNode);

platform/lang-impl/src/com/intellij/lang/customFolding/VisualStudioCustomFoldingProvider.java

@@ -24,7 +24,7 @@ import com.intellij.lang.folding.CustomFoldingProvider;
 public class VisualStudioCustomFoldingProvider extends CustomFoldingProvider {
   @Override
   public boolean isCustomRegionStart(String elementText) {
-    return elementText.contains("region") && elementText.matches("..?\\s*region.*");
+    return elementText.contains("region") && elementText.matches("[/*#-]*\\s*region.*");
   }
 
   @Override
@@ -34,7 +34,7 @@ public class VisualStudioCustomFoldingProvider extends CustomFoldingProvider {
 
   @Override
   public String getPlaceholderText(String elementText) {
-    return elementText.replaceFirst("..?\\s*region(.*)","$1").trim();
+    return elementText.replaceFirst("[/*#-]*\\s*region(.*)","$1").trim();
   }
 
   @Override

xml/tests/src/com/intellij/xml/XmlFoldingTest.java

@@ -35,6 +35,8 @@ public class XmlFoldingTest extends LightPlatformCodeInsightFixtureTestCase {
 
   public void testDataUri() throws Throwable { doTest(); }
 
+  public void testCustomRegions() throws Throwable { doTest(); }
+
   private void doTest() throws Throwable {
     doTest(".html");
   }

xml/tests/testData/folding/customRegions.html

@@ -0,0 +1,15 @@
+<html<fold text='...'>>
+<body<fold text='...'>>
+<div<fold text='...'>>
+  First
+  </div</fold>>
+<!--<fold text='Description'>region Description-->
+<div<fold text='...'>>
+  Second
+  </div</fold>>
+<div<fold text='...'>>
+  Third
+  </div</fold>>
+<!--endregion</fold>-->
+</body</fold>>
+</html</fold>>

xml/xml-psi-impl/src/com/intellij/lang/XmlCodeFoldingBuilder.java

@@ -16,6 +16,7 @@
 
 package com.intellij.lang;
 
+import com.intellij.lang.folding.CustomFoldingBuilder;
 import com.intellij.lang.folding.FoldingBuilder;
 import com.intellij.lang.folding.FoldingDescriptor;
 import com.intellij.lang.folding.LanguageFolding;
@@ -40,17 +41,18 @@ import com.intellij.xml.util.XmlTagUtil;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
-import java.util.ArrayList;
 import java.util.List;
 
-public abstract class XmlCodeFoldingBuilder implements FoldingBuilder, DumbAware {
+public abstract class XmlCodeFoldingBuilder extends CustomFoldingBuilder implements DumbAware {
   private static final TokenSet XML_ATTRIBUTE_SET = TokenSet.create(XmlElementType.XML_ATTRIBUTE);
   private static final int MIN_TEXT_RANGE_LENGTH = 3;
 
   @Override
-  @NotNull
-  public FoldingDescriptor[] buildFoldRegions(@NotNull ASTNode node, @NotNull Document document) {
-    final PsiElement psiElement = node.getPsi();
+  public void buildLanguageFoldRegions(@NotNull List<FoldingDescriptor> foldings,
+                                       @NotNull PsiElement psiElement,
+                                       @NotNull Document document,
+                                       boolean quick
+  ) {
     XmlDocument xmlDocument = null;
 
     if (psiElement instanceof XmlFile) {
@@ -65,15 +67,11 @@ public abstract class XmlCodeFoldingBuilder implements FoldingBuilder, DumbAware
     if (rootTag == null) {
       rootTag = xmlDocument;
     }
-    List<FoldingDescriptor> foldings = null;
 
     if (rootTag != null) {
-      foldings = new ArrayList<>();
 
       doAddForChildren(xmlDocument, foldings, document);
     }
-
-    return foldings != null ? foldings.toArray(new FoldingDescriptor[foldings.size()]):FoldingDescriptor.EMPTY;
   }
 
   protected void addElementsToFold(List<FoldingDescriptor> foldings, XmlElement tag, Document document) {
@@ -224,7 +222,7 @@ public abstract class XmlCodeFoldingBuilder implements FoldingBuilder, DumbAware
   }
 
   @Override
-  public String getPlaceholderText(@NotNull ASTNode node) {
+  public String getLanguagePlaceholderText(@NotNull ASTNode node, @NotNull TextRange range) {
     final PsiElement psi = node.getPsi();
     if (psi instanceof XmlAttribute && "src".equalsIgnoreCase(((XmlAttribute)psi).getName())) {
       return "data:";
@@ -265,7 +263,7 @@ public abstract class XmlCodeFoldingBuilder implements FoldingBuilder, DumbAware
   }
 
   @Override
-  public boolean isCollapsedByDefault(@NotNull ASTNode node) {
+  public boolean isRegionCollapsedByDefault(@NotNull ASTNode node) {
     final PsiElement psi = node.getPsi();
     final XmlCodeFoldingSettings foldingSettings = getFoldingSettings();
     return (psi instanceof XmlTag && foldingSettings.isCollapseXmlTags())
@@ -293,4 +291,14 @@ public abstract class XmlCodeFoldingBuilder implements FoldingBuilder, DumbAware
   }
 
   protected abstract XmlCodeFoldingSettings getFoldingSettings();
+
+  @Override
+  protected boolean isCustomFoldingRoot(@NotNull ASTNode node) {
+    return node.getElementType() == XmlElementType.XML_TAG;
+  }
+
+  @Override
+  protected boolean isCustomFoldingCandidate(@NotNull ASTNode node) {
+    return node.getElementType() == XmlTokenType.XML_COMMENT_CHARACTERS;
+  }
 }