/*******************************************************************************
* Copyright (c) 2005, 2010, 2013 IBM Corporation and others.
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
* IBM Corporation - initial API and implementation
* Sergey Prigogin, Google
* Anton Leherbauer (Wind River Systems)
* Red Hat Inc. - modified for use in SystemTap
*******************************************************************************/
package org.eclipse.linuxtools.internal.systemtap.ui.ide.editors.stp;
import org.eclipse.core.resources.IProject;
import org.eclipse.jface.text.BadLocationException;
import org.eclipse.jface.text.IDocument;
import org.eclipse.jface.text.IRegion;
import org.eclipse.jface.text.ITypedRegion;
import org.eclipse.jface.text.TextUtilities;
import org.eclipse.jface.text.source.ILineRange;
/**
* Utility that indents a number of lines in a document.
*/
public final class IndentUtil {
private static final String SLASHES= "//"; //$NON-NLS-1$
/**
* The result of an indentation operation. The result may be passed to
* subsequent calls to
* {@link IndentUtil#indentLines(IDocument, ILineRange, IProject, IndentUtil.IndentResult) indentLines}
* to obtain consistent results with respect to the indentation of
* line-comments.
*/
public static final class IndentResult {
private IndentResult(boolean[] commentLines) {
commentLinesAtColumnZero= commentLines;
}
private boolean[] commentLinesAtColumnZero;
}
private IndentUtil() {
// do not instantiate
}
/**
* Indents the line range specified by <code>lines</code> in
* <code>document</code>. The passed C project may be
* <code>null</code>, it is used solely to obtain formatter preferences.
*
* @param document the document to be changed
* @param lines the line range to be indented
* @param project the C project to get the formatter preferences from, or
* <code>null</code> if global preferences should be used
* @param result the result from a previous call to <code>indentLines</code>,
* in order to maintain comment line properties, or <code>null</code>.
* Note that the passed result may be changed by the call.
* @return an indent result that may be queried for changes and can be
* reused in subsequent indentation operations
* @throws BadLocationException if <code>lines</code> is not a valid line
* range on <code>document</code>
*/
public static IndentResult indentLines(IDocument document, ILineRange lines, IProject project, IndentResult result) throws BadLocationException {
int numberOfLines= lines.getNumberOfLines();
if (numberOfLines < 1)
return new IndentResult(null);
result= reuseOrCreateToken(result, numberOfLines);
STPHeuristicScanner scanner= new STPHeuristicScanner(document);
STPIndenter indenter= new STPIndenter(document, scanner, project);
boolean indentInsideLineComments= true;
for (int line= lines.getStartLine(), last= line + numberOfLines, i= 0; line < last; line++) {
indentLine(document, line, indenter, scanner, result.commentLinesAtColumnZero, i++, indentInsideLineComments);
}
return result;
}
/**
* Returns the indentation of the line <code>line</code> in <code>document</code>.
* The returned string may contain pairs of leading slashes that are considered
* part of the indentation.
*
* @param document the document
* @param line the line
* @param indentInsideLineComments option whether to indent inside line comments starting at column 0
* @return the indentation of <code>line</code> in <code>document</code>
* @throws BadLocationException if the document is changed concurrently
*/
public static String getCurrentIndent(IDocument document, int line, boolean indentInsideLineComments) throws BadLocationException {
IRegion region= document.getLineInformation(line);
int from= region.getOffset();
int endOffset= region.getOffset() + region.getLength();
int to= from;
if (indentInsideLineComments) {
// go behind line comments
while (to < endOffset - 2 && document.get(to, 2).equals(SLASHES))
to += 2;
}
while (to < endOffset) {
char ch= document.getChar(to);
if (!Character.isWhitespace(ch))
break;
to++;
}
return document.get(from, to - from);
}
private static IndentResult reuseOrCreateToken(IndentResult token, int numberOfLines) {
if (token == null)
token= new IndentResult(new boolean[numberOfLines]);
else if (token.commentLinesAtColumnZero == null)
token.commentLinesAtColumnZero= new boolean[numberOfLines];
else if (token.commentLinesAtColumnZero.length != numberOfLines) {
boolean[] commentBooleans= new boolean[numberOfLines];
System.arraycopy(token.commentLinesAtColumnZero, 0, commentBooleans, 0, Math.min(numberOfLines, token.commentLinesAtColumnZero.length));
token.commentLinesAtColumnZero= commentBooleans;
}
return token;
}
/**
* Indents a single line using the heuristic scanner. Multiline comments are
* indented as specified by the <code>CCommentAutoIndentStrategy</code>.
*
* @param document the document
* @param line the line to be indented
* @param indenter the C indenter
* @param scanner the heuristic scanner
* @param commentLines the indent token comment booleans
* @param lineIndex the zero-based line index
* @param indentInsideLineComments option whether to indent inside line comments
* starting at column 0
* @throws BadLocationException if the document got changed concurrently
*/
private static void indentLine(IDocument document, int line, STPIndenter indenter,
STPHeuristicScanner scanner, boolean[] commentLines, int lineIndex,
boolean indentInsideLineComments) throws BadLocationException {
IRegion currentLine= document.getLineInformation(line);
final int offset= currentLine.getOffset();
int wsStart= offset; // where we start searching for non-WS; after the "//" in single line comments
String indent= null;
if (offset < document.getLength()) {
ITypedRegion partition= TextUtilities.getPartition(document, STPPartitionScanner.STP_PARTITIONING, offset, true);
ITypedRegion startingPartition= TextUtilities.getPartition(document, STPPartitionScanner.STP_PARTITIONING, offset, false);
String type= partition.getType();
if (type.equals(STPPartitionScanner.STP_MULTILINE_COMMENT)) {
indent= computeCommentIndent(document, line, scanner, startingPartition);
} else if (startingPartition.getType().equals(STPPartitionScanner.STP_CONDITIONAL)) {
indent= computePreprocessorIndent(document, line, startingPartition);
} else if (!commentLines[lineIndex] && startingPartition.getOffset() == offset && startingPartition.getType().equals(STPPartitionScanner.STP_COMMENT)) {
return;
}
}
// standard C code indentation
if (indent == null) {
StringBuilder computed= indenter.computeIndentation(offset);
if (computed != null)
indent= computed.toString();
else
indent= ""; //$NON-NLS-1$
}
// change document:
// get current white space
int lineLength= currentLine.getLength();
int end= scanner.findNonWhitespaceForwardInAnyPartition(wsStart, offset + lineLength);
if (end == STPHeuristicScanner.NOT_FOUND)
end= offset + lineLength;
int length= end - offset;
String currentIndent= document.get(offset, length);
// memorize the fact that a line is a single line comment (but not at column 0) and should be treated like code
// as opposed to commented out code, which should keep its slashes at column 0
// if 'indentInsideLineComments' is false, all comment lines are indented with the code
if (length > 0 || !indentInsideLineComments) {
ITypedRegion partition= TextUtilities.getPartition(document, STPPartitionScanner.STP_PARTITIONING, end, false);
if (partition.getOffset() == end && STPPartitionScanner.STP_COMMENT.equals(partition.getType())) {
commentLines[lineIndex]= true;
}
}
// only change the document if it is a real change
if (!indent.equals(currentIndent)) {
document.replace(offset, length, indent);
}
}
/**
* Computes and returns the indentation for a source line.
*
* @param document the document
* @param line the line in document
* @param indenter the C indenter
* @param scanner the scanner
* @return the indent, never <code>null</code>
* @throws BadLocationException
*/
public static String computeIndent(IDocument document, int line, STPIndenter indenter, STPHeuristicScanner scanner) throws BadLocationException {
IRegion currentLine= document.getLineInformation(line);
final int offset= currentLine.getOffset();
String indent= null;
if (offset < document.getLength()) {
ITypedRegion partition= TextUtilities.getPartition(document, STPPartitionScanner.STP_PARTITIONING, offset, true);
ITypedRegion startingPartition= TextUtilities.getPartition(document, STPPartitionScanner.STP_PARTITIONING, offset, false);
String type= partition.getType();
if (type.equals(STPPartitionScanner.STP_COMMENT)) {
indent= computeCommentIndent(document, line, scanner, startingPartition);
} else if (startingPartition.getType().equals(STPPartitionScanner.STP_CONDITIONAL)) {
indent= computePreprocessorIndent(document, line, startingPartition);
}
}
// standard C code indentation
if (indent == null) {
StringBuilder computed= indenter.computeIndentation(offset);
if (computed != null) {
indent= computed.toString();
} else {
indent= ""; //$NON-NLS-1$
}
}
return indent;
}
/**
* Computes and returns the indentation for a block comment line.
*
* @param document the document
* @param line the line in document
* @param scanner the scanner
* @param partition the comment partition
* @return the indent, or <code>null</code> if not computable
* @throws BadLocationException
*/
public static String computeCommentIndent(IDocument document, int line, STPHeuristicScanner scanner, ITypedRegion partition) throws BadLocationException {
if (line == 0) { // impossible - the first line is never inside a comment
return null;
}
// don't make any assumptions if the line does not start with \s*\* - it might be
// commented out code, for which we don't want to change the indent
final IRegion lineInfo= document.getLineInformation(line);
final int lineStart= lineInfo.getOffset();
final int lineLength= lineInfo.getLength();
final int lineEnd= lineStart + lineLength;
int nonWS= scanner.findNonWhitespaceForwardInAnyPartition(lineStart, lineEnd);
if (nonWS == STPHeuristicScanner.NOT_FOUND || document.getChar(nonWS) != '*') {
if (nonWS == STPHeuristicScanner.NOT_FOUND) {
return document.get(lineStart, lineLength);
}
return document.get(lineStart, nonWS - lineStart);
}
// take the indent from the previous line and reuse
IRegion previousLine= document.getLineInformation(line - 1);
int previousLineStart= previousLine.getOffset();
int previousLineLength= previousLine.getLength();
int previousLineEnd= previousLineStart + previousLineLength;
StringBuilder buf= new StringBuilder();
int previousLineNonWS= scanner.findNonWhitespaceForwardInAnyPartition(previousLineStart, previousLineEnd);
if (previousLineNonWS == STPHeuristicScanner.NOT_FOUND || document.getChar(previousLineNonWS) != '*') {
// align with the comment start if the previous line is not an asterix line
previousLine= document.getLineInformationOfOffset(partition.getOffset());
previousLineStart= previousLine.getOffset();
previousLineLength= previousLine.getLength();
previousLineEnd= previousLineStart + previousLineLength;
previousLineNonWS= scanner.findNonWhitespaceForwardInAnyPartition(previousLineStart, previousLineEnd);
if (previousLineNonWS == STPHeuristicScanner.NOT_FOUND) {
previousLineNonWS= previousLineEnd;
}
// add the initial space
// TODO this may be controlled by a formatter preference in the future
buf.append(' ');
}
String indentation= document.get(previousLineStart, previousLineNonWS - previousLineStart);
buf.insert(0, indentation);
return buf.toString();
}
/**
* Computes and returns the indentation for a preprocessor line.
*
* @param document the document
* @param line the line in document
* @param partition the comment partition
* @return the indent, or <code>null</code> if not computable
* @throws BadLocationException
*/
public static String computePreprocessorIndent(IDocument document, int line, ITypedRegion partition)
throws BadLocationException {
int ppFirstLine= document.getLineOfOffset(partition.getOffset());
if (line == ppFirstLine) {
return ""; //$NON-NLS-1$
}
STPHeuristicScanner ppScanner= new STPHeuristicScanner(document, STPPartitionScanner.STP_CONDITIONAL, partition.getType());
STPIndenter ppIndenter= new STPIndenter(document, ppScanner);
if (line == ppFirstLine + 1) {
return ppIndenter.createReusingIndent(new StringBuilder(), ppIndenter.getContinuationLineIndent(), 0).toString();
}
StringBuilder computed= ppIndenter.computeIndentation(document.getLineOffset(line), false);
if (computed != null) {
return computed.toString();
}
// take the indent from the previous line and reuse
IRegion previousLine= document.getLineInformation(line - 1);
int previousLineStart= previousLine.getOffset();
int previousLineLength= previousLine.getLength();
int previousLineEnd= previousLineStart + previousLineLength;
int previousLineNonWS= ppScanner.findNonWhitespaceForwardInAnyPartition(previousLineStart, previousLineEnd);
String previousIndent= document.get(previousLineStart, previousLineNonWS - previousLineStart);
computed= new StringBuilder(previousIndent);
return computed.toString();
}
}