com.telink.tc32eclipse.core.paths.SystemPathHelper.java Source code

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Here is the source code for com.telink.tc32eclipse.core.paths.SystemPathHelper.java

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/******************************************************************************
 * Copyright (c) 2009-2016 Telink Semiconductor Co., LTD.
 *
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the GNU Public License v3
 * which accompanies this distribution, and is available at
 * http://www.gnu.org/licenses/gpl.html
 * -----------------------------------------------------------------------------
 * Module:
 * Purpose:
 * Reference :   
 * $Id: DirectoryNotStrictVariableFieldEditor.java 851 20.1.08-07 19:37:00Z innot $
 *******************************************************************************/
/******************************************************************************
* Copyright (c) 2009-2016 Telink Semiconductor Co., LTD.
*
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the GNU Public License v3
* which accompanies this distribution, and is available at
* http://www.gnu.org/licenses/gpl.html
* -----------------------------------------------------------------------------
* Module:
* Purpose:
* Reference :
* $Id: SystemPathHelper.java 851 21.0.38-07 19:37:00Z innot $
*     
*******************************************************************************/
package com.telink.tc32eclipse.core.paths;

import java.io.File;
import java.util.HashMap;
import java.util.Map;

import org.eclipse.core.runtime.IPath;
import org.eclipse.core.runtime.Path;
import org.eclipse.core.runtime.Platform;
import org.eclipse.jface.preference.IPreferenceStore;

import com.telink.tc32eclipse.core.paths.posix.SystemPathsPosix;
import com.telink.tc32eclipse.core.paths.win32.SystemPathsWin32;
import com.telink.tc32eclipse.core.preferences.TC32PathsPreferences;

/**
 * Convenience class to get the current operating system dependent path for a given resource.
 * 
 * This class acts as a switch to the the operating system dependent </code>IPathProvider</code>s.
 * 
 * @author Peter Shieh
 * @since 0.1
 */
public final class SystemPathHelper {

    private final static String CACHE_TAG = "syspath/";

    private final static Map<TC32Path, IPath> fPathCache = new HashMap<TC32Path, IPath>(TC32Path.values().length);

    /**
     * Get the path to a resource, depending on the operating system.
     * 
     * @param TC32path
     *            TC32Path for which to get the system path.
     * @param force
     *            If <code>true</code> reload the system path directly, without using any cached
     *            values.
     * 
     * @return IPath with the current system path.
     */
    public synchronized static IPath getPath(TC32Path TC32path, boolean force) {

        // if force flag not set check the caches first
        if (!force) {
            // Check if the path is already in the instance cache
            if (fPathCache.containsKey(TC32path)) {
                IPath cachedpath = fPathCache.get(TC32path);
                if (cachedpath != null && !cachedpath.isEmpty()) {
                    return cachedpath;
                }
            }

            // Check if the path is in the persistent cache

            // If there is an entry in the preference store named "cache_..." and its value is a
            // valid directory path and it contains the test file, then we use it instead of
            // re-searching the system.
            String cachedpath = TC32PathsPreferences.getPreferenceStore().getString(CACHE_TAG + TC32path.name());
            if (cachedpath.length() > 0) {
                // Test if the path contains the required test file
                IPath testpath = new Path(cachedpath).append(TC32path.getTest());
                File file = testpath.toFile();
                if (file.canRead()) {
                    IPath path = new Path(cachedpath);
                    fPathCache.put(TC32path, path);
                    return path;
                }
                // Test with ".exe" appended for Windows systems
                testpath = new Path(cachedpath).append(TC32path.getTest() + ".exe");
                file = testpath.toFile();
                if (file.canRead()) {
                    IPath path = new Path(cachedpath);
                    fPathCache.put(TC32path, path);
                    return path;
                }
            }
        }

        // If either the force flag was set or the path was not found in either cache, then
        // search
        // for the path.

        IPath path = null;
        if (isWindows()) {
            path = SystemPathsWin32.getSystemPath(TC32path);
        } else {
            // posix path provider
            path = SystemPathsPosix.getSystemPath(TC32path);
        }

        // if a path was found then store it in both caches
        if (path.getDevice() != null) {
            // instance cache
            fPathCache.put(TC32path, path);

            // persistent cache
            TC32PathsPreferences.getPreferenceStore().putValue(CACHE_TAG + TC32path.name(),
                    // PS path.toOSString());
                    path.toPortableString());
        }

        return path;

    }

    /**
     * Clear both the instance and the persistent system path cache.
     * <p>
     * This method is currently not used in the plugin.
     * </p>
     */
    public synchronized static void clearCache() {

        // Clear the instance cache
        fPathCache.clear();

        // Clear the persistent cache
        IPreferenceStore prefs = TC32PathsPreferences.getPreferenceStore();
        for (TC32Path TC32path : TC32Path.values()) {
            if (prefs.contains(CACHE_TAG + TC32path.name())) {
                prefs.setToDefault(CACHE_TAG + TC32path.name());
            }
        }
    }

    /**
     * @return true if running on windows
     */
    private static boolean isWindows() {
        return (Platform.getOS().equals(Platform.OS_WIN32));
    }

}