corext/util/CodeFormatterUtil.java

/*******************************************************************************
 * Copyright (c) 2000, 2017 IBM Corporation and others.
 *
 * This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License 2.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.jdt.internal.corext.util;

import java.util.Map;

import org.eclipse.core.runtime.Assert;

import org.eclipse.text.edits.TextEdit;

import org.eclipse.jface.text.BadLocationException;
import org.eclipse.jface.text.Document;
import org.eclipse.jface.text.IRegion;

import org.eclipse.jdt.core.IJavaProject;
import org.eclipse.jdt.core.JavaCore;
import org.eclipse.jdt.core.ToolFactory;
import org.eclipse.jdt.core.dom.ASTNode;
import org.eclipse.jdt.core.dom.BodyDeclaration;
import org.eclipse.jdt.core.dom.Expression;
import org.eclipse.jdt.core.dom.Statement;
import org.eclipse.jdt.core.formatter.CodeFormatter;
import org.eclipse.jdt.core.formatter.DefaultCodeFormatterConstants;

import org.eclipse.jdt.internal.core.manipulation.JavaManipulationPlugin;

public class CodeFormatterUtil {

	/**
	 * Creates a string that represents the given number of indentation units.
	 * The returned string can contain tabs and/or spaces depending on the core formatter preferences.
	 *
	 * @param indentationUnits
	 *        the number of indentation units to generate
	 * @param project
	 *        the project from which to get the formatter settings,
	 *        <code>null</code> if the workspace default should be used
	 * @return the indent string
	 */
	public static String createIndentString(int indentationUnits, IJavaProject project) {
		Map<String, String> options= project != null ? project.getOptions(true) : JavaCore.getOptions();
		return ToolFactory.createCodeFormatter(options).createIndentationString(indentationUnits);
	}

	/**
	 * Gets the current tab width.
	 *
	 * @param project
	 *        The project where the source is used, used for project specific options or
	 *        <code>null</code> if the project is unknown and the workspace default should be used
	 * @return The tab width
	 */
	public static int getTabWidth(IJavaProject project) {
		/*
		 * If the tab-char is SPACE, FORMATTER_INDENTATION_SIZE is not used
		 * by the core formatter.
		 * We piggy back the visual tab length setting in that preference in
		 * that case.
		 */
		String key;
		if (JavaCore.SPACE.equals(getCoreOption(project, DefaultCodeFormatterConstants.FORMATTER_TAB_CHAR)))
			key= DefaultCodeFormatterConstants.FORMATTER_INDENTATION_SIZE;
		else
			key= DefaultCodeFormatterConstants.FORMATTER_TAB_SIZE;

		return getCoreOption(project, key, 4);
	}

	/**
	 * Returns the current indent width.
	 *
	 * @param project
	 *        the project where the source is used or,
	 *        <code>null</code> if the project is unknown and the workspace default should be used
	 * @return the indent width
	 * @since 3.1
	 */
	public static int getIndentWidth(IJavaProject project) {
		String key;
		if (DefaultCodeFormatterConstants.MIXED.equals(getCoreOption(project, DefaultCodeFormatterConstants.FORMATTER_TAB_CHAR)))
			key= DefaultCodeFormatterConstants.FORMATTER_INDENTATION_SIZE;
		else
			key= DefaultCodeFormatterConstants.FORMATTER_TAB_SIZE;

		return getCoreOption(project, key, 4);
	}

	/**
	 * Returns the possibly <code>project</code>-specific core preference defined under <code>key</code>.
	 *
	 * @param project
	 *        the project to get the preference from,
	 *        or <code>null</code> to get the global preference
	 * @param key
	 *        the key of the preference
	 * @return the value of the preference
	 * @since 3.1
	 */
	private static String getCoreOption(IJavaProject project, String key) {
		if (project == null)
			return JavaCore.getOption(key);
		return project.getOption(key, true);
	}

	/**
	 * Returns the possibly <code>project</code>-specific core preference defined under <code>key</code>,
	 * or <code>def</code> if the value is not a integer.
	 *
	 * @param project
	 *        the project to get the preference from,
	 *        or <code>null</code> to get the global preference
	 * @param key
	 *        the key of the preference
	 * @param def
	 *        the default value
	 * @return the value of the preference
	 * @since 3.1
	 */
	private static int getCoreOption(IJavaProject project, String key, int def) {
		try {
			return Integer.parseInt(getCoreOption(project, key));
		} catch (NumberFormatException e) {
			return def;
		}
	}

	// transition code

	/**
	 * Old API. Consider to use format2 (TextEdit)
	 *
	 * @param kind
	 *        Use to specify the kind of the code snippet to format.
	 *        It can be any of the kind constants defined in {@link CodeFormatter}
	 * @param source
	 *        The source to format
	 * @param indentationLevel
	 *        The initial indentation level, used to shift left/right the entire source fragment.
	 *        An initial indentation level of zero or below has no effect.
	 * @param lineSeparator
	 *        The line separator to use in formatted source,
	 *        if set to <code>null</code>, then the platform default one will be used.
	 * @param project
	 *        The project from which to retrieve the formatter options from
	 *        If set to <code>null</code>, then use the current settings from {@link JavaCore#getOptions()}.
	 * @return the formatted source string
	 */
	public static String format(int kind, String source, int indentationLevel, String lineSeparator, IJavaProject project) {
		Map<String, String> options= project != null ? project.getOptions(true) : null;
		return format(kind, source, indentationLevel, lineSeparator, options);
	}

	/**
	 * Old API. Consider to use format2 (TextEdit)
	 *
	 * @param kind
	 *        Use to specify the kind of the code snippet to format.
	 *        It can be any of the kind constants defined in {@link CodeFormatter}
	 * @param source
	 *        The source to format
	 * @param indentationLevel
	 *        The initial indentation level, used to shift left/right the entire source fragment.
	 *        An initial indentation level of zero or below has no effect.
	 * @param lineSeparator
	 *        The line separator to use in formatted source,
	 *        if set to <code>null</code>, then the platform default one will be used.
	 * @param options
	 *        The options map to use for formatting with the default code formatter.
	 *        Recognized options are documented on {@link JavaCore#getDefaultOptions()}.
	 *        If set to <code>null</code>, then use the current settings from {@link JavaCore#getOptions()}.
	 * @return the formatted source string
	 */
	public static String format(int kind, String source, int indentationLevel, String lineSeparator, Map<String, String> options) {
		TextEdit edit= format2(kind, source, indentationLevel, lineSeparator, options);
		if (edit == null) {
			return source;
		} else {
			Document document= new Document(source);
			try {
				edit.apply(document, TextEdit.NONE);
			} catch (BadLocationException e) {
				JavaManipulationPlugin.log(e); // bug in the formatter
				Assert.isTrue(false, "Formatter created edits with wrong positions: " + e.getMessage()); //$NON-NLS-1$
			}
			return document.get();
		}
	}

	/**
	 * Creates edits that describe how to format the given string.
	 * Returns <code>null</code> if the code could not be formatted for the given kind.
	 *
	 * @param kind
	 *        Use to specify the kind of the code snippet to format.
	 *        It can be any of the kind constants defined in {@link CodeFormatter}
	 * @param source
	 *        The source to format
	 * @param offset
	 *        The given offset to start recording the edits (inclusive).
	 * @param length the given length to stop recording the edits (exclusive).
	 * @param indentationLevel
	 *        The initial indentation level, used to shift left/right the entire source fragment.
	 *        An initial indentation level of zero or below has no effect.
	 * @param lineSeparator
	 *        The line separator to use in formatted source,
	 *        if set to <code>null</code>, then the platform default one will be used.
	 * @param options
	 *        The options map to use for formatting with the default code formatter.
	 *        Recognized options are documented on {@link JavaCore#getDefaultOptions()}.
	 *        If set to <code>null</code>, then use the current settings from {@link JavaCore#getOptions()}.
	 * @return an TextEdit describing the changes required to format source
	 * @throws IllegalArgumentException
	 *         If the offset and length are not inside the string, a IllegalArgumentException is thrown.
	 */
	public static TextEdit format2(int kind, String source, int offset, int length, int indentationLevel, String lineSeparator, Map<String, String> options) {
		if (offset < 0 || length < 0 || offset + length > source.length()) {
			throw new IllegalArgumentException("offset or length outside of string. offset: " + offset + ", length: " + length + ", string size: " + source.length()); //$NON-NLS-1$//$NON-NLS-2$//$NON-NLS-3$
		}
		return ToolFactory.createCodeFormatter(options).format(kind, source, offset, length, indentationLevel, lineSeparator);
	}

	/**
	 * Creates edits that describe how to format the given string.
	 * Returns <code>null</code> if the code could not be formatted for the given kind.
	 *
	 * @param kind
	 *        Use to specify the kind of the code snippet to format.
	 *        It can be any of the kind constants defined in {@link CodeFormatter}
	 * @param source
	 *        The source to format
	 * @param indentationLevel
	 *        The initial indentation level, used to shift left/right the entire source fragment.
	 *        An initial indentation level of zero or below has no effect.
	 * @param lineSeparator
	 *        The line separator to use in formatted source,
	 *        if set to <code>null</code>, then the platform default one will be used.
	 * @param options
	 *        The options map to use for formatting with the default code formatter.
	 *        Recognized options are documented on {@link JavaCore#getDefaultOptions()}.
	 *        If set to <code>null</code>, then use the current settings from {@link JavaCore#getOptions()}.
	 * @return an TextEdit describing the changes required to format source
	 * @throws IllegalArgumentException
	 *         If the offset and length are not inside the string, a IllegalArgumentException is thrown.
	 */
	public static TextEdit format2(int kind, String source, int indentationLevel, String lineSeparator, Map<String, String> options) {
		return format2(kind, source, 0, source.length(), indentationLevel, lineSeparator, options);
	}

	/**
	 * Creates edits that describe how to re-format the given string.
	 * This method should be used for formatting existing code.
	 * Returns <code>null</code> if the code could not be formatted for the given kind.
	 *
	 * @param kind
	 *        Use to specify the kind of the code snippet to format.
	 *        It can be any of the kind constants defined in {@link CodeFormatter}
	 * @param source
	 *        The source to format
	 * @param offset
	 *        The given offset to start recording the edits (inclusive).
	 * @param length the given length to stop recording the edits (exclusive).
	 * @param indentationLevel
	 *        The initial indentation level, used to shift left/right the entire source fragment.
	 *        An initial indentation level of zero or below has no effect.
	 * @param lineSeparator
	 *        The line separator to use in formatted source,
	 *        if set to <code>null</code>, then the platform default one will be used.
	 * @param options
	 *        The options map to use for formatting with the default code formatter.
	 *        Recognized options are documented on {@link JavaCore#getDefaultOptions()}.
	 *        If set to <code>null</code>, then use the current settings from {@link JavaCore#getOptions()}.
	 * @return an TextEdit describing the changes required to format source
	 * @throws IllegalArgumentException
	 *         If the offset and length are not inside the string, a IllegalArgumentException is thrown.
	 */
	public static TextEdit reformat(int kind, String source, int offset, int length, int indentationLevel, String lineSeparator, Map<String, String> options) {
		if (offset < 0 || length < 0 || offset + length > source.length()) {
			throw new IllegalArgumentException("offset or length outside of string. offset: " + offset + ", length: " + length + ", string size: " + source.length()); //$NON-NLS-1$//$NON-NLS-2$//$NON-NLS-3$
		}
		return ToolFactory.createCodeFormatter(options, ToolFactory.M_FORMAT_EXISTING).format(kind, source, offset, length, indentationLevel, lineSeparator);
	}

	/**
	 * Creates edits that describe how to re-format the regions in the given string.
	 * This method should be used for formatting existing code.
	 * Returns <code>null</code> if the code could not be formatted for the given kind.
	 *
	 * <p>No region in <code>regions</code> must overlap with any other region in <code>regions</code>.
	 * Each region must be within source. There must be at least one region. Regions must be sorted
	 * by their offsets, smaller offset first.</p>
	 *
	 * @param kind
	 *        Use to specify the kind of the code snippet to format.
	 *        It can be any of K_EXPRESSION, K_STATEMENTS, K_CLASS_BODY_DECLARATIONS, K_COMPILATION_UNIT, K_UNKNOWN
	 * @param source
	 *        The source to format
	 * @param regions
	 *        a set of regions in the string to format
	 * @param indentationLevel
	 *        The initial indentation level, used to shift left/right the entire source fragment.
	 *        An initial indentation level of zero or below has no effect.
	 * @param lineSeparator
	 *        The line separator to use in formatted source,
	 *        if set to <code>null</code>, then the platform default one will be used.
	 * @param options
	 *        The options map to use for formatting with the default code formatter.
	 *        Recognized options are documented on {@link JavaCore#getDefaultOptions()}.
	 *        If set to <code>null</code>, then use the current settings from {@link JavaCore#getOptions()}.
	 * @return an TextEdit describing the changes required to format source
	 * @throws IllegalArgumentException if there is no region, a region overlaps with another region, or the regions are not
	 *         sorted in the ascending order.
	 * @since 3.4
	 */
	public static TextEdit reformat(int kind, String source, IRegion[] regions, int indentationLevel, String lineSeparator, Map<String, String> options) {
		return ToolFactory.createCodeFormatter(options, ToolFactory.M_FORMAT_EXISTING).format(kind, source, regions, indentationLevel, lineSeparator);
	}

	/**
	 * Creates edits that describe how to re-format the given string.
	 * This method should be used for formatting existing code.
	 * Returns <code>null</code> if the code could not be formatted for the given kind.
	 *
	 * @param kind
	 *        Use to specify the kind of the code snippet to format.
	 *        It can be any of the kind constants defined in {@link CodeFormatter}
	 * @param source
	 *        The source to format
	 * @param indentationLevel
	 *        The initial indentation level, used to shift left/right the entire source fragment.
	 *        An initial indentation level of zero or below has no effect.
	 * @param lineSeparator
	 *        The line separator to use in formatted source,
	 *        if set to <code>null</code>, then the platform default one will be used.
	 * @param options
	 *        The options map to use for formatting with the default code formatter.
	 *        Recognized options are documented on {@link JavaCore#getDefaultOptions()}.
	 *        If set to <code>null</code>, then use the current settings from {@link JavaCore#getOptions()}.
	 * @return an TextEdit describing the changes required to format source
	 * @throws IllegalArgumentException
	 *         If the offset and length are not inside the string, a IllegalArgumentException is thrown.
	 */
	public static TextEdit reformat(int kind, String source, int indentationLevel, String lineSeparator, Map<String, String> options) {
		return reformat(kind, source, 0, source.length(), indentationLevel, lineSeparator, options);
	}

	/**
	 * Creates edits that describe how to format the given string.
	 * The given node is used to infer the kind to use to format the string.
	 * Consider to use {@link #format2(int, String, int, String, Map)} if the kind is already known.
	 * Returns <code>null</code> if the code could not be formatted for the given kind.
	 *
	 * @param node
	 *        Use to infer the kind of the code snippet to format.
	 * @param source
	 *        The source to format
	 * @param indentationLevel
	 *        The initial indentation level, used to shift left/right the entire source fragment.
	 *        An initial indentation level of zero or below has no effect.
	 * @param lineSeparator
	 *        The line separator to use in formatted source,
	 *        if set to <code>null</code>, then the platform default one will be used.
	 * @param options
	 *        The options map to use for formatting with the default code formatter.
	 *        Recognized options are documented on {@link JavaCore#getDefaultOptions()}.
	 *        If set to <code>null</code>, then use the current settings from {@link JavaCore#getOptions()}.
	 * @return an TextEdit describing the changes required to format source
	 * @throws IllegalArgumentException
	 *         If the offset and length are not inside the string, a IllegalArgumentException is thrown.
	 */
	public static TextEdit format2(ASTNode node, String source, int indentationLevel, String lineSeparator, Map<String, String> options) {
		int code;
		String prefix= ""; //$NON-NLS-1$
		String suffix= ""; //$NON-NLS-1$
		if (node instanceof Statement) {
			code= CodeFormatter.K_STATEMENTS;
			if (node.getNodeType() == ASTNode.SWITCH_CASE) {
				prefix= "switch(1) {"; //$NON-NLS-1$
				suffix= "}"; //$NON-NLS-1$
				code= CodeFormatter.K_STATEMENTS;
			}
		} else if (node instanceof Expression && node.getNodeType() != ASTNode.VARIABLE_DECLARATION_EXPRESSION) {
			code= CodeFormatter.K_EXPRESSION;
		} else if (node instanceof BodyDeclaration) {
			code= CodeFormatter.K_CLASS_BODY_DECLARATIONS;
		} else {
			switch (node.getNodeType()) {
				case ASTNode.ARRAY_TYPE:
				case ASTNode.PARAMETERIZED_TYPE:
				case ASTNode.PRIMITIVE_TYPE:
				case ASTNode.QUALIFIED_TYPE:
				case ASTNode.SIMPLE_TYPE:
					suffix= " x;"; //$NON-NLS-1$
					code= CodeFormatter.K_CLASS_BODY_DECLARATIONS;
					break;
				case ASTNode.WILDCARD_TYPE:
					prefix= "A<"; //$NON-NLS-1$
					suffix= "> x;"; //$NON-NLS-1$
					code= CodeFormatter.K_CLASS_BODY_DECLARATIONS;
					break;
				case ASTNode.COMPILATION_UNIT:
					code= CodeFormatter.K_COMPILATION_UNIT;
					break;
				case ASTNode.MODULE_DECLARATION:
					code= CodeFormatter.K_MODULE_INFO;
					break;
				case ASTNode.VARIABLE_DECLARATION_EXPRESSION:
				case ASTNode.SINGLE_VARIABLE_DECLARATION:
					suffix= ";"; //$NON-NLS-1$
					code= CodeFormatter.K_STATEMENTS;
					break;
				case ASTNode.VARIABLE_DECLARATION_FRAGMENT:
					prefix= "A "; //$NON-NLS-1$
					suffix= ";"; //$NON-NLS-1$
					code= CodeFormatter.K_STATEMENTS;
					break;
				case ASTNode.PACKAGE_DECLARATION:
				case ASTNode.IMPORT_DECLARATION:
					suffix= "\nclass A {}"; //$NON-NLS-1$
					code= CodeFormatter.K_COMPILATION_UNIT;
					break;
				case ASTNode.JAVADOC:
					suffix= "void foo();"; //$NON-NLS-1$
					code= CodeFormatter.K_CLASS_BODY_DECLARATIONS;
					break;
				case ASTNode.CATCH_CLAUSE:
					prefix= "try {}"; //$NON-NLS-1$
					code= CodeFormatter.K_STATEMENTS;
					break;
				case ASTNode.ANONYMOUS_CLASS_DECLARATION:
					prefix= "new A()"; //$NON-NLS-1$
					suffix= ";"; //$NON-NLS-1$
					code= CodeFormatter.K_STATEMENTS;
					break;
				case ASTNode.MEMBER_VALUE_PAIR:
					prefix= "@Author("; //$NON-NLS-1$
					suffix= ") class x {}"; //$NON-NLS-1$
					code= CodeFormatter.K_COMPILATION_UNIT;
					break;
				case ASTNode.MODIFIER:
					suffix= " class x {}"; //$NON-NLS-1$
					code= CodeFormatter.K_COMPILATION_UNIT;
					break;
				case ASTNode.TYPE_PARAMETER:
					prefix= "class X<"; //$NON-NLS-1$
					suffix= "> {}"; //$NON-NLS-1$
					code= CodeFormatter.K_COMPILATION_UNIT;
					break;
				case ASTNode.MEMBER_REF:
				case ASTNode.METHOD_REF:
				case ASTNode.METHOD_REF_PARAMETER:
				case ASTNode.TAG_ELEMENT:
				case ASTNode.TEXT_ELEMENT:
					// Javadoc formatting not yet supported:
					return null;
				default:
					//Assert.isTrue(false, "Node type not covered: " + node.getClass().getName()); //$NON-NLS-1$
					return null;
			}
		}

		String concatStr= prefix + source + suffix;
		TextEdit edit= format2(code, concatStr, prefix.length(), source.length(), indentationLevel, lineSeparator, options);
		if (edit != null && prefix.length() > 0) {
			edit.moveTree(-prefix.length());
		}
		return edit;
	}

	private CodeFormatterUtil() {
	}

}