Copyright (c) 2000, 2013 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
/*******************************************************************************
 * Copyright (c) 2000, 2013 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.debug.internal.core;

import java.net.URL;

import org.eclipse.core.runtime.CoreException;
import org.eclipse.core.runtime.IPath;
import org.eclipse.core.runtime.Path;
import org.eclipse.core.runtime.Platform;
import org.eclipse.core.variables.IDynamicVariable;
import org.eclipse.core.variables.IDynamicVariableResolver;

Resolves common system variables. The current set of variables
supported (referenced as an argument to this variable) are:

ARCH - value of BootLoader.getOSArch()
ECLIPSE_HOME - location of the Eclipse installation
NL - value of BootLoader.getNL()
OS - value of BootLoader.getOS()
WS - value of BootLoader.getWS()

Since:
3.0/**
 * Resolves common system variables. The current set of variables
 * supported (referenced as an argument to this variable) are:
 * <ul>
 * <li>ARCH - value of <code>BootLoader.getOSArch()</code></li>
 * <li>ECLIPSE_HOME - location of the Eclipse installation</li>
 * <li>NL - value of <code>BootLoader.getNL()</code></li>
 * <li>OS - value of <code>BootLoader.getOS()</code></li>
 * <li>WS - value of <code>BootLoader.getWS()</code></li>
 * </ul>
 * @since 3.0
 */
public class SystemVariableResolver implements IDynamicVariableResolver {
	@Override
	public String resolveValue(IDynamicVariable variable, String argument) throws CoreException {
		if ("ARCH".equals(argument)) { //$NON-NLS-1$
			return Platform.getOSArch();
		} else if ("ECLIPSE_HOME".equals(argument)) { //$NON-NLS-1$
			URL installURL = Platform.getInstallLocation().getURL();
			IPath ppath = new Path(installURL.getFile()).removeTrailingSeparator();
			return getCorrectPath(ppath.toOSString());
		} else if ("NL".equals(argument)) { //$NON-NLS-1$
			return Platform.getNL();
		} else if ("OS".equals(argument)) { //$NON-NLS-1$
			return Platform.getOS();
		} else if ("WS".equals(argument)) { //$NON-NLS-1$
			return Platform.getWS();
		}
		return null;
	}

	private static String getCorrectPath(String path) {
		StringBuilder buf = new StringBuilder();
		for (int i = 0; i < path.length(); i++) {
			char c = path.charAt(i);
			if (Platform.getOS().equals("win32")) { //$NON-NLS-1$
				if (i == 0 && c == '/') {
					continue;
				}
			}
			// Some VMs may return %20 instead of a space
			if (c == '%' && i + 2 < path.length()) {
				char c1 = path.charAt(i + 1);
				char c2 = path.charAt(i + 2);
				if (c1 == '2' && c2 == '0') {
					i += 2;
					buf.append(" "); //$NON-NLS-1$
					continue;
				}
			}
			buf.append(c);
		}
		return buf.toString();
	}
}