IDEA-29781 With "Smart home" enabled, pressing Home inside Javadoc comment should jump to first non-whitespace character after leading asterisk (*)

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

@@ -0,0 +1,74 @@
+/*
+ * 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.openapi.actionSystem.DataContext;
+import com.intellij.openapi.editor.Caret;
+import com.intellij.openapi.editor.Document;
+import com.intellij.openapi.editor.Editor;
+import com.intellij.openapi.editor.EditorModificationUtil;
+import com.intellij.openapi.editor.actionSystem.EditorActionHandler;
+import com.intellij.openapi.editor.actionSystem.EditorWriteActionHandler;
+import com.intellij.openapi.editor.ex.EditorSettingsExternalizable;
+import com.intellij.openapi.project.Project;
+import com.intellij.psi.*;
+import com.intellij.psi.javadoc.PsiDocToken;
+import com.intellij.psi.tree.IElementType;
+import com.intellij.util.text.CharArrayUtil;
+import org.jetbrains.annotations.Nullable;
+
+public class JavadocLineStartHandler extends EditorWriteActionHandler {
+  private static final String WHITESPACE = " \t";
+  
+  private final EditorActionHandler myOriginalHandler;
+
+  public JavadocLineStartHandler(EditorActionHandler originalHandler) {
+    super(true);
+    myOriginalHandler = originalHandler;
+  }
+
+  @Override
+  public void executeWriteAction(Editor editor, @Nullable Caret caret, DataContext dataContext) {
+    assert caret != null;
+    Project project = editor.getProject();
+    if (project != null && EditorSettingsExternalizable.getInstance().isSmartHome()) {
+      Document document = editor.getDocument();
+      CharSequence text = document.getImmutableCharSequence();
+      int lineStartOffset = document.getLineStartOffset(caret.getLogicalPosition().line);
+      int nonWsStartOffset = CharArrayUtil.shiftForward(text, lineStartOffset, WHITESPACE);
+      if (CharArrayUtil.regionMatches(text, nonWsStartOffset, "/**") || CharArrayUtil.regionMatches(text, nonWsStartOffset, "*")) {
+        PsiDocumentManager psiDocumentManager = PsiDocumentManager.getInstance(project);
+        PsiFile file = psiDocumentManager.getPsiFile(document);
+        if (file instanceof PsiJavaFile) {
+          psiDocumentManager.commitDocument(document);
+          PsiElement startElement = file.findElementAt(nonWsStartOffset);
+          if (startElement instanceof PsiDocToken) {
+            IElementType type = ((PsiDocToken)startElement).getTokenType();
+            if (type == JavaDocTokenType.DOC_COMMENT_START || type == JavaDocTokenType.DOC_COMMENT_LEADING_ASTERISKS) {
+              int targetOffset = CharArrayUtil.shiftForward(text, startElement.getTextRange().getEndOffset(), WHITESPACE);
+              if (caret.getOffset() == targetOffset) targetOffset = lineStartOffset;
+              caret.moveToOffset(targetOffset);
+              caret.removeSelection();
+              EditorModificationUtil.scrollToCaret(editor);
+              return;
+            }
+          }
+        }
+      }
+    }
+    myOriginalHandler.execute(editor, caret, dataContext);    
+  }
+}

java/java-tests/testSrc/com/intellij/codeInsight/editorActions/JavaEditingTest.java

@@ -0,0 +1,34 @@
+/*
+ * 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.openapi.editor.impl.AbstractEditorTest;
+import com.intellij.testFramework.TestFileType;
+
+public class JavaEditingTest extends AbstractEditorTest {
+  public void testSmartHomeInJavadoc() throws Exception {
+    init("/**\n" +
+         " * some text<caret>\n" +
+         " */\n" +
+         "class C {}", 
+         TestFileType.JAVA);
+    home();
+    checkResultByText("/**\n" +
+                      " * <caret>some text\n" +
+                      " */\n" +
+                      "class C {}");
+  }
+}

resources/src/META-INF/IdeaPlugin.xml

@@ -1365,6 +1365,8 @@
 
     <editorTypedHandler implementationClass="com.intellij.codeInsight.editorActions.AutoFormatTypedHandler"/>
 
+    <editorActionHandler action="EditorLineStart" implementationClass="com.intellij.codeInsight.editorActions.JavadocLineStartHandler"/>
+
     <editorSmartKeysConfigurable instance="com.intellij.application.options.JavadocOptionsProvider"
                                  id="editor.preferences.javadocOptions"
                                  key="javadoc.generate.message.title"