LineIndentProvider API with a simple example for JavaScript

platform/lang-impl/src/com/intellij/codeInsight/editorActions/EnterHandler.java

@@ -484,7 +484,7 @@ public class EnterHandler extends BaseEnterHandler {
     private int adjustLineIndent(CharSequence docChars) {
       int indentStart = CharArrayUtil.shiftBackwardUntil(docChars, myOffset - 1, "\n") + 1;
       int indentEnd = CharArrayUtil.shiftForward(docChars, indentStart, " \t");
-      String newIndent = CodeStyleFacade.getInstance(getProject()).getLineIndent(myDocument, myOffset);
+      String newIndent = CodeStyleFacade.getInstance(getProject()).getLineIndent(myEditor, myDocument, myOffset);
       if (newIndent == null) return myOffset;
       int delta = newIndent.length() - (indentEnd - indentStart);
       myDocument.replaceString(indentStart, indentEnd, newIndent);

platform/lang-impl/src/com/intellij/psi/impl/source/codeStyle/CodeStyleFacadeImpl.java

@@ -22,10 +22,12 @@ package com.intellij.psi.impl.source.codeStyle;
 import com.intellij.codeStyle.CodeStyleFacade;
 import com.intellij.lang.Language;
 import com.intellij.openapi.editor.Document;
+import com.intellij.openapi.editor.Editor;
 import com.intellij.openapi.fileTypes.FileType;
 import com.intellij.openapi.options.Configurable;
 import com.intellij.openapi.project.Project;
 import com.intellij.psi.PsiDocumentManager;
+import com.intellij.psi.PsiFile;
 import com.intellij.psi.codeStyle.CodeStyleManager;
 import com.intellij.psi.codeStyle.CodeStyleSettingsManager;
 import org.jetbrains.annotations.NotNull;
@@ -49,12 +51,22 @@ public class CodeStyleFacadeImpl extends CodeStyleFacade {
 
   @Override
   @Nullable
+  @Deprecated
   public String getLineIndent(@NotNull final Document document, int offset) {
     if (myProject == null) return null;
     PsiDocumentManager.getInstance(myProject).commitDocument(document);
     return CodeStyleManager.getInstance(myProject).getLineIndent(document, offset);
   }
 
+  @Override
+  public String getLineIndent(@NotNull Editor editor, @NotNull Document document, int offset) {
+    if (myProject == null) return null;
+    PsiDocumentManager documentManager = PsiDocumentManager.getInstance(myProject);
+    PsiFile file = documentManager.getPsiFile(document);
+    LineIndentProvider lineIndentProvider = LineIndentProviderEP.findLineIndentProvider(file);
+    return lineIndentProvider != null ? lineIndentProvider.getLineIndent(myProject, editor, document, offset) : null;
+  }
+
   @Override
   public String getLineSeparator() {
     return CodeStyleSettingsManager.getSettings(myProject).getLineSeparator();

platform/lang-impl/src/com/intellij/psi/impl/source/codeStyle/FormatterBasedLineIndentProvider.java

@@ -0,0 +1,42 @@
+/*
+ * Copyright 2000-2016 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.psi.impl.source.codeStyle;
+
+import com.intellij.openapi.editor.Document;
+import com.intellij.openapi.editor.Editor;
+import com.intellij.openapi.project.Project;
+import com.intellij.psi.PsiDocumentManager;
+import com.intellij.psi.PsiFile;
+import com.intellij.psi.codeStyle.CodeStyleManager;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+/**
+ * Formatter-based line indent provider which calculates indent using formatting model.
+ */
+public class FormatterBasedLineIndentProvider implements LineIndentProvider {
+  @Nullable
+  @Override
+  public String getLineIndent(@NotNull Project project, @NotNull Editor editor, @NotNull Document document, int offset) {
+    PsiDocumentManager.getInstance(project).commitDocument(document);
+    return CodeStyleManager.getInstance(project).getLineIndent(document, offset);
+  }
+
+  @Override
+  public boolean isSuitableFor(@Nullable PsiFile file) {
+    return true;
+  }
+}

platform/lang-impl/src/com/intellij/psi/impl/source/codeStyle/JavaLikeLangLineIndentProvider.java

@@ -0,0 +1,91 @@
+/*
+ * Copyright 2000-2016 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.psi.impl.source.codeStyle;
+
+import com.intellij.formatting.Indent;
+import com.intellij.lang.Language;
+import com.intellij.openapi.editor.Document;
+import com.intellij.openapi.editor.Editor;
+import com.intellij.openapi.editor.ex.EditorEx;
+import com.intellij.openapi.editor.highlighter.EditorHighlighter;
+import com.intellij.openapi.editor.highlighter.HighlighterIterator;
+import com.intellij.openapi.project.Project;
+import com.intellij.psi.PsiFile;
+import com.intellij.psi.tree.IElementType;
+import com.intellij.util.text.CharArrayUtil;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+/**
+ * A base class Java-like language line indent provider. If JavaLikeLangLineIndentProvider is unable to calculate
+ * the indentation, it forwards the request to FormatterBasedLineIndentProvider.
+ */
+public abstract class JavaLikeLangLineIndentProvider extends FormatterBasedLineIndentProvider {
+  @Nullable
+  @Override
+  public String getLineIndent(@NotNull Project project, @NotNull Editor editor, @NotNull Document document, int offset) {
+    Indent.Type indent = getIndent(editor, document, offset);
+    if (indent == Indent.Type.NONE) return null;
+    return super.getLineIndent(project, editor, document, offset);
+  }
+
+  @Override
+  public final boolean isSuitableFor(@Nullable PsiFile file) {
+    if (file != null) {
+      return isSuitableForLanguage(file.getLanguage());
+    }
+    return false;
+  }
+  
+  protected abstract boolean isSuitableForLanguage(@NotNull Language language);
+  
+  @Nullable
+  protected Indent.Type getIndent(@NotNull Editor editor, @NotNull Document document, int offset) {
+    CharSequence docChars = document.getCharsSequence();
+    EditorHighlighter highlighter = ((EditorEx)editor).getHighlighter();
+    HighlighterIterator iterator = highlighter.createIterator(offset - 1);
+    if (isWhitespace(iterator.getTokenType())) {
+      if (containsLineBreaks(iterator, docChars)) {
+        iterator.retreat();
+        if (!iterator.atEnd()) {
+          if (isEndOfCodeBlock(iterator)) return Indent.Type.NONE;
+        }
+      }
+    }
+    return null;
+  }
+  
+  protected abstract boolean isWhitespace(@NotNull IElementType tokenType);
+  
+  private static boolean containsLineBreaks(@NotNull HighlighterIterator iterator, @NotNull CharSequence chars) {
+    return CharArrayUtil.containLineBreaks(chars, iterator.getStart(), iterator.getEnd());
+  }
+  
+  protected boolean isEndOfCodeBlock(@NotNull HighlighterIterator iterator) {
+    if (isSemicolon(iterator.getTokenType())) iterator.retreat();
+    if (!iterator.atEnd()) {
+      if (isWhitespace(iterator.getTokenType())) iterator.retreat();
+      if (!iterator.atEnd()) {
+        return isBlockClosingBrace(iterator.getTokenType());
+      }
+    }
+    return false;
+  }
+  
+  protected abstract boolean isSemicolon(@NotNull IElementType tokenType);
+  
+  protected abstract boolean isBlockClosingBrace(@NotNull IElementType tokenType);
+}

platform/lang-impl/src/com/intellij/psi/impl/source/codeStyle/LineIndentProvider.java

@@ -0,0 +1,45 @@
+/*
+ * Copyright 2000-2016 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.psi.impl.source.codeStyle;
+
+import com.intellij.openapi.editor.Document;
+import com.intellij.openapi.editor.Editor;
+import com.intellij.openapi.project.Project;
+import com.intellij.psi.PsiFile;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+/**
+ * An interface for indentation calculation. Used in editor actions like Enter handling.
+ */
+public interface LineIndentProvider {
+  
+  /**
+   * Calculates the indent that should be used for the line at specified offset in the specified
+   * document.
+   *
+   * @param project  The current project.
+   * @param editor   The current editor.
+   * @param document The document for which the indent should be calculated.
+   * @param offset   The caret offset in the editor.
+   * @return The indent string (possibly consisting of tabs and/or white spaces), or null if
+   * LineIndentProvider can't calculate the indent (in this case no indent adjustment will be made).
+   */
+  @Nullable
+  String getLineIndent(@NotNull Project project, @NotNull Editor editor, @NotNull Document document, int offset);
+  
+  boolean isSuitableFor(@Nullable PsiFile file);
+}

platform/lang-impl/src/com/intellij/psi/impl/source/codeStyle/LineIndentProviderEP.java

@@ -0,0 +1,38 @@
+/*
+ * Copyright 2000-2016 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.psi.impl.source.codeStyle;
+
+import com.intellij.openapi.extensions.ExtensionPointName;
+import com.intellij.psi.PsiFile;
+import org.jetbrains.annotations.Nullable;
+
+/**
+ * Line indent provider extension point
+ */
+public class LineIndentProviderEP {
+  public final static ExtensionPointName<LineIndentProvider> EP_NAME = ExtensionPointName.create("com.intellij.lineIndentProvider");
+  
+  @Nullable
+  public static LineIndentProvider findLineIndentProvider(@Nullable PsiFile psiFile) {
+    LineIndentProvider foundProvider = null;
+    for (LineIndentProvider provider : EP_NAME.getExtensions()) {
+      if (foundProvider == null || provider.isSuitableFor(psiFile) && foundProvider.getClass().isInstance(provider)) {
+        foundProvider = provider;
+      }
+    }
+    return foundProvider;
+  }
+}

platform/platform-api/src/com/intellij/codeStyle/CodeStyleFacade.java

@@ -22,6 +22,7 @@ package com.intellij.codeStyle;
 import com.intellij.lang.Language;
 import com.intellij.openapi.components.ServiceManager;
 import com.intellij.openapi.editor.Document;
+import com.intellij.openapi.editor.Editor;
 import com.intellij.openapi.fileTypes.FileType;
 import com.intellij.openapi.options.Configurable;
 import com.intellij.openapi.project.Project;
@@ -46,9 +47,26 @@ public abstract class CodeStyleFacade {
    * @param offset the caret offset in the editor.
    * @return the indent string (containing of tabs and/or white spaces), or null if it
    *         was not possible to calculate the indent.
+   * @deprecated Use {@link #getLineIndent(Editor, Document, int)} instead.
    */
   @Nullable
+  @Deprecated
   public abstract String getLineIndent(@NotNull Document document, int offset);
+  
+  /**
+   * Calculates the indent that should be used for the line at specified offset in the specified
+   * document.
+   *
+   * @param editor the editor for which the indent must be returned.
+   * @param document the document for which the indent should be calculated.
+   * @param offset the caret offset in the editor.
+   * @return the indent string (containing of tabs and/or white spaces), or null if it
+   *         was not possible to calculate the indent.
+   */
+  public String getLineIndent(@NotNull Editor editor, @NotNull Document document, int offset) {
+    //noinspection deprecation
+    return getLineIndent(document, offset);
+  }
 
   public abstract int getIndentSize(FileType fileType);
 

platform/platform-resources/src/META-INF/LangExtensionPoints.xml

@@ -289,6 +289,7 @@
     <extensionPoint name="preFormatProcessor" interface="com.intellij.psi.impl.source.codeStyle.PreFormatProcessor"/>
     <extensionPoint name="postFormatProcessor" interface="com.intellij.psi.impl.source.codeStyle.PostFormatProcessor"/>
     <extensionPoint name="disabledIndentRangesProvider" interface="com.intellij.psi.impl.source.DisabledIndentRangesProvider"/>
+    <extensionPoint name="lineIndentProvider" interface="com.intellij.psi.impl.source.codeStyle.LineIndentProvider"/>
 
     <extensionPoint name="declarationRangeHandler" beanClass="com.intellij.util.MixinEP">
       <with attribute="implementationClass" implements="com.intellij.codeInsight.hint.DeclarationRangeHandler"/>

platform/platform-resources/src/META-INF/LangExtensions.xml

@@ -953,6 +953,7 @@
 
     <nonProjectFileWritingAccessExtension implementation="com.intellij.ide.actions.EditCustomPropertiesAction$AccessExtension"/>
     <nonProjectFileWritingAccessExtension implementation="com.intellij.ide.actions.EditCustomVmOptionsAction$AccessExtension"/>
+    <lineIndentProvider implementation="com.intellij.psi.impl.source.codeStyle.FormatterBasedLineIndentProvider"/>
   </extensions>
 </idea-plugin>