IncludeSearchPathElement.java

/*******************************************************************************
 * Copyright (c) 2009, 2016 Wind River Systems, Inc. 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:
 *     Markus Schorn - initial API and implementation
 *     Sergey Prigogin (Google)
 *******************************************************************************/
package org.eclipse.cdt.internal.core.parser.scanner;

import java.io.File;

import org.eclipse.cdt.utils.PathUtil;
import org.eclipse.core.runtime.IPath;
import org.eclipse.core.runtime.Path;

/**
 * Represents an entry of the include search path
 */
public final class IncludeSearchPathElement {
	private static final boolean NON_SLASH_SEPARATOR = File.separatorChar != '/';
	public static final String FRAMEWORK_VAR = "__framework__"; //$NON-NLS-1$
	public static final String FILE_VAR = "__header__"; //$NON-NLS-1$
	private static final String FRAMEWORK_HEADERS = ".framework/Headers"; //$NON-NLS-1$

	private final String fPath;
	private final boolean fForQuoteIncludesOnly;
	private final boolean fIsFrameworkDirectory;
	private final boolean fIsNewFrameworkDirectory;

	IncludeSearchPathElement(String path, boolean forQuoteIncludesOnly) {
		fPath = path;
		fForQuoteIncludesOnly = forQuoteIncludesOnly;

		if (path.indexOf('_') != -1 && path.indexOf(FRAMEWORK_VAR) != -1 && path.indexOf(FILE_VAR) != -1) {
			fIsFrameworkDirectory = true;
			fIsNewFrameworkDirectory = false;
		} else if (path.endsWith(FRAMEWORK_HEADERS)) {
			fIsFrameworkDirectory = false;
			fIsNewFrameworkDirectory = true;
		} else {
			fIsFrameworkDirectory = false;
			fIsNewFrameworkDirectory = false;
		}
	}

	public boolean isForQuoteIncludesOnly() {
		return fForQuoteIncludesOnly;
	}

	public String getLocation(String includeDirective) {
		if (fIsFrameworkDirectory) {
			int firstSep = firstSeparator(includeDirective);
			if (firstSep <= 0) {
				return null;
			}
			String framework = includeDirective.substring(0, firstSep);
			String file = includeDirective.substring(firstSep + 1);
			if (file.length() == 0)
				return null;

			StringBuilder buf = new StringBuilder(fPath);
			replace(buf, FRAMEWORK_VAR, framework);
			replace(buf, FILE_VAR, file);
			return ScannerUtility.reconcilePath(buf.toString());
		} else if (fIsNewFrameworkDirectory) {
			int firstSep = firstSeparator(includeDirective);
			if (firstSep > 0) {
				String framework = includeDirective.substring(0, firstSep);
				String file = includeDirective.substring(firstSep + 1);
				if (file.length() > 0) {
					if (fPath.endsWith(framework + FRAMEWORK_HEADERS)) {
						return ScannerUtility.createReconciledPath(fPath, file);
					}
				}
			}
		}
		return ScannerUtility.createReconciledPath(fPath, includeDirective);
	}

	/**
	 * Returns the include directive for the given location satisfying the
	 * condition {@code getLocation(getIncludeDirective(location) == location}.
	 * If no such include directive without ".." exists, returns {@code null}.
	 */
	public String getIncludeDirective(String location) {
		IPath dirPath = new Path(fPath);
		IPath locationPath = new Path(location);
		if (fIsFrameworkDirectory) {
			if (dirPath.segmentCount() != locationPath.segmentCount())
				return null;
			int i = PathUtil.matchingFirstSegments(dirPath, locationPath);
			String dirSegment = dirPath.segment(i);
			String locationSegment = locationPath.segment(i);
			String framework = deduceVariable(FRAMEWORK_VAR, dirSegment, locationSegment);
			if (framework == null)
				return null;
			i++;
			dirPath = dirPath.removeFirstSegments(i);
			locationPath = locationPath.removeFirstSegments(i);
			i = PathUtil.matchingFirstSegments(dirPath, locationPath);
			if (i < dirPath.segmentCount() - 1)
				return null;
			dirSegment = dirPath.segment(i);
			locationSegment = locationPath.segment(i);
			String file = deduceVariable(FILE_VAR, dirSegment, locationSegment);
			if (file == null)
				return null;
			return framework + '/' + file;
		}

		if (!PathUtil.isPrefix(dirPath, locationPath))
			return null;
		return locationPath.removeFirstSegments(dirPath.segmentCount()).setDevice(null).toPortableString();
	}

	private int firstSeparator(String path) {
		int firstSep = path.indexOf('/');
		if (NON_SLASH_SEPARATOR) {
			firstSep = Math.max(firstSep, path.indexOf(File.separatorChar));
		}
		return firstSep;
	}

	private void replace(StringBuilder buf, String find, final String replace) {
		int idx = buf.indexOf(find);
		if (idx >= 0) {
			buf.replace(idx, idx + find.length(), replace);
		}
	}

	private String deduceVariable(String varName, String raw, String substituted) {
		int pos = raw.indexOf(varName);
		if (pos < 0)
			return null;
		int suffixLength = raw.length() - pos - varName.length();
		if (substituted.length() <= pos + suffixLength)
			return null;
		for (int i = 0; i < suffixLength; i++) {
			if (raw.charAt(raw.length() - i) != substituted.charAt(substituted.length() - i))
				return null;
		}
		return substituted.substring(pos, substituted.length() - suffixLength);
	}

	/**
	 * For debugging only.
	 */
	@Override
	public String toString() {
		return fPath;
	}
}