IDEA-178801 Multi-line pasting in line comments

java/java-impl/src/com/intellij/codeInsight/editorActions/LineCommentCopyPastePreProcessor.java

@@ -0,0 +1,60 @@
+/*
+ * Copyright 2000-2017 JetBrains s.r.o.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.intellij.codeInsight.editorActions;
+
+import com.intellij.lang.java.JavaLanguage;
+import com.intellij.openapi.editor.Document;
+import com.intellij.openapi.editor.Editor;
+import com.intellij.openapi.editor.RawText;
+import com.intellij.openapi.project.Project;
+import com.intellij.psi.PsiFile;
+import com.intellij.psi.PsiJavaFile;
+import com.intellij.psi.codeStyle.CodeStyleSettings;
+import com.intellij.psi.codeStyle.CodeStyleSettingsManager;
+import com.intellij.util.DocumentUtil;
+import com.intellij.util.text.CharArrayUtil;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+public class LineCommentCopyPastePreProcessor implements CopyPastePreProcessor {
+  @Nullable
+  @Override
+  public String preprocessOnCopy(PsiFile file, int[] startOffsets, int[] endOffsets, String text) {
+    return null;
+  }
+
+  @NotNull
+  @Override
+  public String preprocessOnPaste(Project project, PsiFile file, Editor editor, String text, RawText rawText) {
+    if (!(file instanceof PsiJavaFile)) return text;
+
+    Document document = editor.getDocument();
+    int offset = editor.getSelectionModel().getSelectionStart();
+    int lineStartOffset = DocumentUtil.getLineStartOffset(offset, document);
+    CharSequence chars = document.getImmutableCharSequence();
+    int firstNonWsLineOffset = CharArrayUtil.shiftForward(chars, lineStartOffset, " \t");
+    if (offset >= (firstNonWsLineOffset + 2) && 
+        chars.charAt(firstNonWsLineOffset) == '/' && chars.charAt(firstNonWsLineOffset + 1) == '/') {
+      CodeStyleSettings codeStyleSettings = CodeStyleSettingsManager.getSettings(project);
+      String lineStartReplacement = "\n" + chars.subSequence(lineStartOffset, firstNonWsLineOffset + 2) +
+                                    (codeStyleSettings.getCommonSettings(JavaLanguage.INSTANCE).LINE_COMMENT_ADD_SPACE ? " " : "");
+      return text.replace("\n", lineStartReplacement);
+    }
+    else {
+      return text;
+    }
+  }
+}

resources/src/META-INF/IdeaPlugin.xml

@@ -1524,6 +1524,7 @@
     <liveTemplateMacro implementation="com.intellij.codeInsight.template.macro.TypeOfVariableMacro"/>
 
 
+    <copyPastePreProcessor implementation="com.intellij.codeInsight.editorActions.LineCommentCopyPastePreProcessor"/>
     <copyPastePreProcessor implementation="com.intellij.codeInsight.editorActions.StringLiteralCopyPasteProcessor"/>
     <copyPastePostProcessor implementation="com.intellij.codeInsight.editorActions.JavaCopyPasteReferenceProcessor"/>