Add proper folding for line and block comments in JSON

Also line comments separated by more than one line feed are not moved together.

json/src/com/intellij/json/editor/folding/JsonFoldingBuilder.java

@@ -1,16 +1,15 @@
 package com.intellij.json.editor.folding;
 
 import com.intellij.json.JsonElementTypes;
-import com.intellij.json.psi.JsonLiteral;
-import com.intellij.json.psi.JsonObject;
-import com.intellij.json.psi.JsonProperty;
-import com.intellij.json.psi.JsonValue;
+import com.intellij.json.psi.*;
 import com.intellij.lang.ASTNode;
 import com.intellij.lang.folding.FoldingBuilder;
 import com.intellij.lang.folding.FoldingDescriptor;
 import com.intellij.openapi.editor.Document;
 import com.intellij.openapi.project.DumbAware;
+import com.intellij.openapi.util.Couple;
 import com.intellij.openapi.util.TextRange;
+import com.intellij.psi.PsiElement;
 import com.intellij.psi.tree.IElementType;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
@@ -37,6 +36,18 @@ public class JsonFoldingBuilder implements FoldingBuilder, DumbAware {
     if ((type == JsonElementTypes.OBJECT || type == JsonElementTypes.ARRAY) && spanMultipleLines(node, document)) {
       descriptors.add(new FoldingDescriptor(node, node.getTextRange()));
     }
+    else if (type == JsonElementTypes.BLOCK_COMMENT) {
+      descriptors.add(new FoldingDescriptor(node, node.getTextRange()));
+    }
+    else if (type == JsonElementTypes.LINE_COMMENT) {
+      final Couple<PsiElement> commentRange = JsonPsiUtil.expandLineCommentsRange(node.getPsi());
+      final int startOffset = commentRange.getFirst().getTextRange().getStartOffset();
+      final int endOffset = commentRange.getSecond().getTextRange().getEndOffset();
+      if (document.getLineNumber(startOffset) != document.getLineNumber(endOffset)) {
+        descriptors.add(new FoldingDescriptor(node, new TextRange(startOffset, endOffset)));
+      }
+    }
+
     for (ASTNode child : node.getChildren(null)) {
       collectDescriptorsRecursively(child, document, descriptors);
     }
@@ -72,6 +83,12 @@ public class JsonFoldingBuilder implements FoldingBuilder, DumbAware {
     else if (type == JsonElementTypes.ARRAY) {
       return "[...]";
     }
+    else if (type == JsonElementTypes.LINE_COMMENT) {
+      return "//...";
+    }
+    else if (type == JsonElementTypes.BLOCK_COMMENT) {
+      return "/*...*/";
+    }
     return "...";
   }
 

json/src/com/intellij/json/editor/lineMover/JsonLineMover.java

@@ -4,7 +4,6 @@ import com.intellij.codeInsight.editorActions.moveUpDown.LineMover;
 import com.intellij.codeInsight.editorActions.moveUpDown.LineRange;
 import com.intellij.json.JsonElementTypes;
 import com.intellij.json.psi.*;
-import com.intellij.lang.ASTNode;
 import com.intellij.openapi.editor.Document;
 import com.intellij.openapi.editor.Editor;
 import com.intellij.openapi.project.Project;
@@ -74,25 +73,9 @@ public class JsonLineMover extends LineMover {
 
   @NotNull
   private Pair<PsiElement, PsiElement> expandCommentsInRange(@NotNull Pair<PsiElement, PsiElement> range) {
-    final PsiElement firstElement = expandComment(range.first, true);
-    final PsiElement lastElement = expandComment(range.second, false);
-    return Pair.create(firstElement, lastElement);
-  }
-
-  @NotNull
-  private PsiElement expandComment(@NotNull PsiElement first, boolean before) {
-    ASTNode node = first.getNode();
-    if (node.getElementType() != JsonElementTypes.LINE_COMMENT) {
-      return first;
-    }
-    ASTNode sibling;
-    do {
-      sibling = node;
-      node = before ? node.getTreePrev() : node.getTreeNext();
-    }
-    while (node != null && (node.getElementType() == JsonElementTypes.LINE_COMMENT ||
-                            sibling.getElementType() == JsonElementTypes.LINE_COMMENT));
-    return (before ? sibling.getTreeNext() : sibling.getTreePrev()).getPsi();
+    final PsiElement upper = JsonPsiUtil.findOutermostLineComment(range.getFirst(), false);
+    final PsiElement lower = JsonPsiUtil.findOutermostLineComment(range.getSecond(), true);
+    return Pair.create(upper, lower);
   }
 
   @Override

json/src/com/intellij/json/psi/JsonPsiUtil.java

@@ -1,6 +1,11 @@
 package com.intellij.json.psi;
 
+import com.intellij.json.JsonElementTypes;
+import com.intellij.lang.ASTNode;
+import com.intellij.openapi.util.Couple;
 import com.intellij.psi.PsiElement;
+import com.intellij.psi.TokenType;
+import com.intellij.psi.tree.IElementType;
 import org.jetbrains.annotations.NotNull;
 
 /**
@@ -46,4 +51,37 @@ public class JsonPsiUtil {
     final PsiElement parent = element.getParent();
     return parent instanceof JsonProperty && element == ((JsonProperty)parent).getValue();
   }
+
+  /**
+   * Find largest region of successive line comments that includes given one.
+   * @param anchor anchor line comment from which range will be expanded
+   * @return specified range of comments or pair {@code (anchor, anchor)} if anchor is not line comment
+   */
+  @NotNull
+  public static Couple<PsiElement> expandLineCommentsRange(@NotNull PsiElement anchor) {
+    return Couple.of(findOutermostLineComment(anchor, false), findOutermostLineComment(anchor, true));
+  }
+
+  /**
+   * Lowest or topmost successive line comment for given anchor element.
+   * @param anchor start element (most probably another line comment)
+   * @param below whether to scan through element forward or backward
+   * @return described {@link com.intellij.psi.PsiComment} element or {@code anchor} if it's not a line comment
+   */
+  @NotNull
+  public static PsiElement findOutermostLineComment(@NotNull PsiElement anchor, boolean below) {
+    ASTNode node = anchor.getNode();
+    ASTNode lastSeenComment = node;
+    while (node != null) {
+      final IElementType elementType = node.getElementType();
+      if (elementType == JsonElementTypes.LINE_COMMENT) {
+        lastSeenComment = node;
+      }
+      else if (elementType != TokenType.WHITE_SPACE || node.getText().indexOf('\n', 1) != -1) {
+        break;
+      }
+      node = below ? node.getTreeNext() : node.getTreePrev();
+    }
+    return lastSeenComment.getPsi();
+  }
 }

json/tests/test/com/intellij/json/JsonFoldingTest.java

@@ -17,6 +17,10 @@ public class JsonFoldingTest extends JsonTestCase {
     doTest();
   }
 
+  public void testCommentaries() {
+    doTest();
+  }
+
   // Moved from JavaScript
 
   public void testObjectLiteral2() {

json/tests/testData/folding/Commentaries.json

@@ -0,0 +1,11 @@
+// Single line comment is not folded.
+
+<fold text='//...'>// But
+// several comments
+// are.</fold>
+<fold text='{"foo": 42...}'>{
+<fold text='/*...*/'>/* Block commentaries
+are always folded however.
+*/</fold>
+"foo": 42
+}</fold>

json/tests/testData/mover/LineCommentariesMovedTogether.json

@@ -1,5 +1,7 @@
 {
   "foo": true,
+  // This line won't be moved
+
   // Line<caret> 1
   // Line 2
   "bar": false

json/tests/testData/mover/LineCommentariesMovedTogether_afterDown.json

@@ -1,5 +1,7 @@
 {
   "foo": true,
+  // This line won't be moved
+
   "bar": false
   // Line 1
   // Line 2

json/tests/testData/mover/LineCommentariesMovedTogether_afterUp.json

@@ -1,6 +1,7 @@
 {
+  "foo": true,
+  // This line won't be moved
   // Line 1
   // Line 2
-  "foo": true,
   "bar": false
 }