xref: /sdk/eclipse/plugins/com.android.ide.eclipse.adt/src/com/android/ide/eclipse/adt/internal/sdk/Sdk.java

/*
 * Copyright (C) 2008 The Android Open Source Project
 *
 * Licensed under the Eclipse Public License, Version 1.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.eclipse.org/org/documents/epl-v10.php
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.android.ide.eclipse.adt.internal.sdk;

import com.android.ddmlib.IDevice;
import com.android.ide.eclipse.adt.AdtPlugin;
import com.android.ide.eclipse.adt.internal.project.AndroidClasspathContainerInitializer;
import com.android.ide.eclipse.adt.internal.project.BaseProjectHelper;
import com.android.ide.eclipse.adt.internal.project.ProjectHelper;
import com.android.ide.eclipse.adt.internal.resources.manager.GlobalProjectMonitor;
import com.android.ide.eclipse.adt.internal.resources.manager.GlobalProjectMonitor.IFileListener;
import com.android.ide.eclipse.adt.internal.resources.manager.GlobalProjectMonitor.IProjectListener;
import com.android.ide.eclipse.adt.internal.resources.manager.GlobalProjectMonitor.IResourceEventListener;
import com.android.ide.eclipse.adt.internal.sdk.AndroidTargetData.LayoutBridge;
import com.android.ide.eclipse.adt.internal.sdk.ProjectState.LibraryDifference;
import com.android.ide.eclipse.adt.internal.sdk.ProjectState.LibraryState;
import com.android.prefs.AndroidLocation.AndroidLocationException;
import com.android.sdklib.AndroidVersion;
import com.android.sdklib.IAndroidTarget;
import com.android.sdklib.ISdkLog;
import com.android.sdklib.SdkConstants;
import com.android.sdklib.SdkManager;
import com.android.sdklib.internal.avd.AvdManager;
import com.android.sdklib.internal.project.ProjectProperties;
import com.android.sdklib.internal.project.ProjectPropertiesWorkingCopy;
import com.android.sdklib.internal.project.ProjectProperties.PropertyType;
import com.android.sdklib.io.StreamException;

import org.eclipse.core.resources.IFile;
import org.eclipse.core.resources.IFolder;
import org.eclipse.core.resources.IMarkerDelta;
import org.eclipse.core.resources.IPathVariableManager;
import org.eclipse.core.resources.IProject;
import org.eclipse.core.resources.IProjectDescription;
import org.eclipse.core.resources.IResource;
import org.eclipse.core.resources.IResourceDelta;
import org.eclipse.core.resources.IWorkspaceRoot;
import org.eclipse.core.resources.IncrementalProjectBuilder;
import org.eclipse.core.resources.ResourcesPlugin;
import org.eclipse.core.runtime.CoreException;
import org.eclipse.core.runtime.IPath;
import org.eclipse.core.runtime.IProgressMonitor;
import org.eclipse.core.runtime.IStatus;
import org.eclipse.core.runtime.Path;
import org.eclipse.core.runtime.Status;
import org.eclipse.core.runtime.jobs.Job;
import org.eclipse.jdt.core.IClasspathEntry;
import org.eclipse.jdt.core.IJavaProject;
import org.eclipse.jdt.core.JavaCore;

import java.io.File;
import java.io.IOException;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.Map.Entry;

/**
 * Central point to load, manipulate and deal with the Android SDK. Only one SDK can be used
 * at the same time.
 *
 * To start using an SDK, call {@link #loadSdk(String)} which returns the instance of
 * the Sdk object.
 *
 * To get the list of platforms or add-ons present in the SDK, call {@link #getTargets()}.
 */
public final class Sdk  {
    private static final String PROP_LIBRARY = "_library"; //$NON-NLS-1$
    private static final String PROP_LIBRARY_NAME = "_library_name"; //$NON-NLS-1$
    public static final String CREATOR_ADT = "ADT";        //$NON-NLS-1$
    public static final String PROP_CREATOR = "_creator";  //$NON-NLS-1$
    private final static Object sLock = new Object();

    private static Sdk sCurrentSdk = null;

    /**
     * Map associating {@link IProject} and their state {@link ProjectState}.
     * <p/>This <b>MUST NOT</b> be accessed directly. Instead use {@link #getProjectState(IProject)}.
     */
    private final static HashMap<IProject, ProjectState> sProjectStateMap =
            new HashMap<IProject, ProjectState>();

    /**
     * Data bundled using during the load of Target data.
     * <p/>This contains the {@link LoadStatus} and a list of projects that attempted
     * to compile before the loading was finished. Those projects will be recompiled
     * at the end of the loading.
     */
    private final static class TargetLoadBundle {
        LoadStatus status;
        final HashSet<IJavaProject> projecsToReload = new HashSet<IJavaProject>();
    }

    private final SdkManager mManager;
    private final AvdManager mAvdManager;

    /** Map associating an {@link IAndroidTarget} to an {@link AndroidTargetData} */
    private final HashMap<IAndroidTarget, AndroidTargetData> mTargetDataMap =
        new HashMap<IAndroidTarget, AndroidTargetData>();
    /** Map associating an {@link IAndroidTarget} and its {@link TargetLoadBundle}. */
    private final HashMap<IAndroidTarget, TargetLoadBundle> mTargetDataStatusMap =
        new HashMap<IAndroidTarget, TargetLoadBundle>();

    private final String mDocBaseUrl;

    private final LayoutDeviceManager mLayoutDeviceManager = new LayoutDeviceManager();

    /**
     * Classes implementing this interface will receive notification when targets are changed.
     */
    public interface ITargetChangeListener {
        /**
         * Sent when project has its target changed.
         */
        void onProjectTargetChange(IProject changedProject);

        /**
         * Called when the targets are loaded (either the SDK finished loading when Eclipse starts,
         * or the SDK is changed).
         */
        void onTargetLoaded(IAndroidTarget target);

        /**
         * Called when the base content of the SDK is parsed.
         */
        void onSdkLoaded();
    }

    /**
     * Basic abstract implementation of the ITargetChangeListener for the case where both
     * {@link #onProjectTargetChange(IProject)} and {@link #onTargetLoaded(IAndroidTarget)}
     * use the same code based on a simple test requiring to know the current IProject.
     */
    public static abstract class TargetChangeListener implements ITargetChangeListener {
        /**
         * Returns the {@link IProject} associated with the listener.
         */
        public abstract IProject getProject();

        /**
         * Called when the listener needs to take action on the event. This is only called
         * if {@link #getProject()} and the {@link IAndroidTarget} associated with the project
         * match the values received in {@link #onProjectTargetChange(IProject)} and
         * {@link #onTargetLoaded(IAndroidTarget)}.
         */
        public abstract void reload();

        public void onProjectTargetChange(IProject changedProject) {
            if (changedProject != null && changedProject.equals(getProject())) {
                reload();
            }
        }

        public void onTargetLoaded(IAndroidTarget target) {
            IProject project = getProject();
            if (target != null && target.equals(Sdk.getCurrent().getTarget(project))) {
                reload();
            }
        }

        public void onSdkLoaded() {
            // do nothing;
        }
    }

    /**
     * Returns the lock object used to synchronize all operations dealing with SDK, targets and
     * projects.
     */
    public static final Object getLock() {
        return sLock;
    }

    /**
     * Loads an SDK and returns an {@link Sdk} object if success.
     * <p/>If the SDK failed to load, it displays an error to the user.
     * @param sdkLocation the OS path to the SDK.
     */
    public static Sdk loadSdk(String sdkLocation) {
        synchronized (sLock) {
            if (sCurrentSdk != null) {
                sCurrentSdk.dispose();
                sCurrentSdk = null;
            }

            final ArrayList<String> logMessages = new ArrayList<String>();
            ISdkLog log = new ISdkLog() {
                public void error(Throwable throwable, String errorFormat, Object... arg) {
                    if (errorFormat != null) {
                        logMessages.add(String.format("Error: " + errorFormat, arg));
                    }

                    if (throwable != null) {
                        logMessages.add(throwable.getMessage());
                    }
                }

                public void warning(String warningFormat, Object... arg) {
                    logMessages.add(String.format("Warning: " + warningFormat, arg));
                }

                public void printf(String msgFormat, Object... arg) {
                    logMessages.add(String.format(msgFormat, arg));
                }
            };

            // get an SdkManager object for the location
            SdkManager manager = SdkManager.createManager(sdkLocation, log);
            if (manager != null) {
                AvdManager avdManager = null;
                try {
                    avdManager = new AvdManager(manager, log);
                } catch (AndroidLocationException e) {
                    log.error(e, "Error parsing the AVDs");
                }
                sCurrentSdk = new Sdk(manager, avdManager);
                return sCurrentSdk;
            } else {
                StringBuilder sb = new StringBuilder("Error Loading the SDK:\n");
                for (String msg : logMessages) {
                    sb.append('\n');
                    sb.append(msg);
                }
                AdtPlugin.displayError("Android SDK", sb.toString());
            }
            return null;
        }
    }

    /**
     * Returns the current {@link Sdk} object.
     */
    public static Sdk getCurrent() {
        synchronized (sLock) {
            return sCurrentSdk;
        }
    }

    /**
     * Returns the location (OS path) of the current SDK.
     */
    public String getSdkLocation() {
        return mManager.getLocation();
    }

    /**
     * Returns the URL to the local documentation.
     * Can return null if no documentation is found in the current SDK.
     *
     * @return A file:// URL on the local documentation folder if it exists or null.
     */
    public String getDocumentationBaseUrl() {
        return mDocBaseUrl;
    }

    /**
     * Returns the list of targets that are available in the SDK.
     */
    public IAndroidTarget[] getTargets() {
        return mManager.getTargets();
    }

    /**
     * Returns a target from a hash that was generated by {@link IAndroidTarget#hashString()}.
     *
     * @param hash the {@link IAndroidTarget} hash string.
     * @return The matching {@link IAndroidTarget} or null.
     */
    public IAndroidTarget getTargetFromHashString(String hash) {
        return mManager.getTargetFromHashString(hash);
    }

    /**
     * Initializes a new project with a target. This creates the <code>default.properties</code>
     * file.
     * @param project the project to intialize
     * @param target the project's target.
     * @throws IOException if creating the file failed in any way.
     * @throws StreamException
     */
    public void initProject(IProject project, IAndroidTarget target)
            throws IOException, StreamException {
        if (project == null || target == null) {
            return;
        }

        synchronized (sLock) {
            // check if there's already a state?
            ProjectState state = getProjectState(project);

            ProjectPropertiesWorkingCopy properties = null;

            if (state != null) {
                properties = state.getProperties().makeWorkingCopy();
            }

            if (properties == null) {
                IPath location = project.getLocation();
                if (location == null) {  // can return null when the project is being deleted.
                    // do nothing and return null;
                    return;
                }

                properties = ProjectProperties.create(location.toOSString(), PropertyType.DEFAULT);
            }

            // save the target hash string in the project persistent property
            properties.setProperty(ProjectProperties.PROPERTY_TARGET, target.hashString());
            properties.save();
        }
    }

    /**
     * Returns the {@link ProjectState} object associated with a given project.
     * <p/>
     * This method is the only way to properly get the project's {@link ProjectState}
     * If the project has not yet been loaded, then it is loaded.
     * <p/>Because this methods deals with projects, it's not linked to an actual {@link Sdk}
     * objects, and therefore is static.
     * <p/>The value returned by {@link ProjectState#getTarget()} will change as {@link Sdk} objects
     * are replaced.
     * @param project the request project
     * @return the ProjectState for the project.
     */
    public static ProjectState getProjectState(IProject project) {
        if (project == null) {
            return null;
        }

        synchronized (sLock) {
            ProjectState state = sProjectStateMap.get(project);
            if (state == null) {
                // load the default.properties from the project folder.
                IPath location = project.getLocation();
                if (location == null) {  // can return null when the project is being deleted.
                    // do nothing and return null;
                    return null;
                }

                ProjectProperties properties = ProjectProperties.load(location.toOSString(),
                        PropertyType.DEFAULT);
                if (properties == null) {
                    AdtPlugin.log(IStatus.ERROR, "Failed to load properties file for project '%s'",
                            project.getName());
                    return null;
                }

                state = new ProjectState(project, properties);
                sProjectStateMap.put(project, state);

                // try to resolve the target
                if (AdtPlugin.getDefault().getSdkLoadStatus() == LoadStatus.LOADED) {
                    sCurrentSdk.loadTarget(state);
                }
            }

            return state;
        }
    }

    /**
     * Returns the {@link IAndroidTarget} object associated with the given {@link IProject}.
     */
    public IAndroidTarget getTarget(IProject project) {
        if (project == null) {
            return null;
        }

        ProjectState state = getProjectState(project);
        if (state != null) {
            return state.getTarget();
        }

        return null;
    }

    /**
     * Loads the {@link IAndroidTarget} for a given project.
     * <p/>This method will get the target hash string from the project properties, and resolve
     * it to an {@link IAndroidTarget} object and store it inside the {@link ProjectState}.
     * @param state the state representing the project to load.
     * @return the target that was loaded.
     */
    public IAndroidTarget loadTarget(ProjectState state) {
        IAndroidTarget target = null;
        String hash = state.getTargetHashString();
        if (hash != null) {
            state.setTarget(target = getTargetFromHashString(hash));
        }

        return target;
    }

    /**
     * Checks and loads (if needed) the data for a given target.
     * <p/> The data is loaded in a separate {@link Job}, and opened editors will be notified
     * through their implementation of {@link ITargetChangeListener#onTargetLoaded(IAndroidTarget)}.
     * <p/>An optional project as second parameter can be given to be recompiled once the target
     * data is finished loading.
     * <p/>The return value is non-null only if the target data has already been loaded (and in this
     * case is the status of the load operation)
     * @param target the target to load.
     * @param project an optional project to be recompiled when the target data is loaded.
     * If the target is already loaded, nothing happens.
     * @return The load status if the target data is already loaded.
     */
    public LoadStatus checkAndLoadTargetData(final IAndroidTarget target, IJavaProject project) {
        boolean loadData = false;

        synchronized (sLock) {
            TargetLoadBundle bundle = mTargetDataStatusMap.get(target);
            if (bundle == null) {
                bundle = new TargetLoadBundle();
                mTargetDataStatusMap.put(target,bundle);

                // set status to loading
                bundle.status = LoadStatus.LOADING;

                // add project to bundle
                if (project != null) {
                    bundle.projecsToReload.add(project);
                }

                // and set the flag to start the loading below
                loadData = true;
            } else if (bundle.status == LoadStatus.LOADING) {
                // add project to bundle
                if (project != null) {
                    bundle.projecsToReload.add(project);
                }

                return bundle.status;
            } else if (bundle.status == LoadStatus.LOADED || bundle.status == LoadStatus.FAILED) {
                return bundle.status;
            }
        }

        if (loadData) {
            Job job = new Job(String.format("Loading data for %1$s", target.getFullName())) {
                @Override
                protected IStatus run(IProgressMonitor monitor) {
                    AdtPlugin plugin = AdtPlugin.getDefault();
                    try {
                        IStatus status = new AndroidTargetParser(target).run(monitor);

                        IJavaProject[] javaProjectArray = null;

                        synchronized (sLock) {
                            TargetLoadBundle bundle = mTargetDataStatusMap.get(target);

                            if (status.getCode() != IStatus.OK) {
                                bundle.status = LoadStatus.FAILED;
                                bundle.projecsToReload.clear();
                            } else {
                                bundle.status = LoadStatus.LOADED;

                                // Prepare the array of project to recompile.
                                // The call is done outside of the synchronized block.
                                javaProjectArray = bundle.projecsToReload.toArray(
                                        new IJavaProject[bundle.projecsToReload.size()]);

                                // and update the UI of the editors that depend on the target data.
                                plugin.updateTargetListeners(target);
                            }
                        }

                        if (javaProjectArray != null) {
                            AndroidClasspathContainerInitializer.updateProjects(javaProjectArray);
                        }

                        return status;
                    } catch (Throwable t) {
                        synchronized (sLock) {
                            TargetLoadBundle bundle = mTargetDataStatusMap.get(target);
                            bundle.status = LoadStatus.FAILED;
                        }

                        AdtPlugin.log(t, "Exception in checkAndLoadTargetData.");    //$NON-NLS-1$
                        return new Status(IStatus.ERROR, AdtPlugin.PLUGIN_ID,
                                String.format(
                                        "Parsing Data for %1$s failed", //$NON-NLS-1$
                                        target.hashString()),
                                t);
                    }
                }
            };
            job.setPriority(Job.BUILD); // build jobs are run after other interactive jobs
            job.schedule();
        }

        // The only way to go through here is when the loading starts through the Job.
        // Therefore the current status of the target is LOADING.
        return LoadStatus.LOADING;
    }

    /**
     * Return the {@link AndroidTargetData} for a given {@link IAndroidTarget}.
     */
    public AndroidTargetData getTargetData(IAndroidTarget target) {
        synchronized (sLock) {
            return mTargetDataMap.get(target);
        }
    }

    /**
     * Return the {@link AndroidTargetData} for a given {@link IProject}.
     */
    public AndroidTargetData getTargetData(IProject project) {
        synchronized (sLock) {
            IAndroidTarget target = getTarget(project);
            if (target != null) {
                return getTargetData(target);
            }
        }

        return null;
    }

    /**
     * Returns the {@link AvdManager}. If the AvdManager failed to parse the AVD folder, this could
     * be <code>null</code>.
     */
    public AvdManager getAvdManager() {
        return mAvdManager;
    }

    public static AndroidVersion getDeviceVersion(IDevice device) {
        try {
            Map<String, String> props = device.getProperties();
            String apiLevel = props.get(IDevice.PROP_BUILD_API_LEVEL);
            if (apiLevel == null) {
                return null;
            }

            return new AndroidVersion(Integer.parseInt(apiLevel),
                    props.get((IDevice.PROP_BUILD_CODENAME)));
        } catch (NumberFormatException e) {
            return null;
        }
    }

    public LayoutDeviceManager getLayoutDeviceManager() {
        return mLayoutDeviceManager;
    }

    /**
     * Returns a list of {@link ProjectState} representing projects depending, directly or
     * indirectly on a given library project.
     * @param project the library project.
     * @return a possibly empty list of ProjectState.
     */
    public static Set<ProjectState> getMainProjectsFor(IProject project) {
        synchronized (sLock) {
            // first get the project directly depending on this.
            HashSet<ProjectState> list = new HashSet<ProjectState>();

            // loop on all project and see if ProjectState.getLibrary returns a non null
            // project.
            for (Entry<IProject, ProjectState> entry : sProjectStateMap.entrySet()) {
                if (project != entry.getKey()) {
                    LibraryState library = entry.getValue().getLibrary(project);
                    if (library != null) {
                        list.add(entry.getValue());
                    }
                }
            }

            // now look for projects depending on the projects directly depending on the library.
            HashSet<ProjectState> result = new HashSet<ProjectState>(list);
            for (ProjectState p : list) {
                if (p.isLibrary()) {
                    Set<ProjectState> set = getMainProjectsFor(p.getProject());
                    result.addAll(set);
                }
            }

            return result;
        }
    }

    private Sdk(SdkManager manager, AvdManager avdManager) {
        mManager = manager;
        mAvdManager = avdManager;

        // listen to projects closing
        GlobalProjectMonitor monitor = GlobalProjectMonitor.getMonitor();
        monitor.addProjectListener(mProjectListener);
        monitor.addFileListener(mFileListener, IResourceDelta.CHANGED | IResourceDelta.ADDED);
        monitor.addResourceEventListener(mResourceEventListener);

        // pre-compute some paths
        mDocBaseUrl = getDocumentationBaseUrl(mManager.getLocation() +
                SdkConstants.OS_SDK_DOCS_FOLDER);

        // load the built-in and user layout devices
        mLayoutDeviceManager.loadDefaultAndUserDevices(mManager.getLocation());
        // and the ones from the add-on
        loadLayoutDevices();

        // update whatever ProjectState is already present with new IAndroidTarget objects.
        synchronized (sLock) {
            for (Entry<IProject, ProjectState> entry: sProjectStateMap.entrySet()) {
                entry.getValue().setTarget(
                        getTargetFromHashString(entry.getValue().getTargetHashString()));
            }
        }
    }

    /**
     *  Cleans and unloads the SDK.
     */
    private void dispose() {
        GlobalProjectMonitor monitor = GlobalProjectMonitor.getMonitor();
        monitor.removeProjectListener(mProjectListener);
        monitor.removeFileListener(mFileListener);
        monitor.removeResourceEventListener(mResourceEventListener);

        // the IAndroidTarget objects are now obsolete so update the project states.
        synchronized (sLock) {
            for (Entry<IProject, ProjectState> entry: sProjectStateMap.entrySet()) {
                entry.getValue().setTarget(null);
            }
        }
    }

    void setTargetData(IAndroidTarget target, AndroidTargetData data) {
        synchronized (sLock) {
            mTargetDataMap.put(target, data);
        }
    }

    /**
     * Returns the URL to the local documentation.
     * Can return null if no documentation is found in the current SDK.
     *
     * @param osDocsPath Path to the documentation folder in the current SDK.
     *  The folder may not actually exist.
     * @return A file:// URL on the local documentation folder if it exists or null.
     */
    private String getDocumentationBaseUrl(String osDocsPath) {
        File f = new File(osDocsPath);

        if (f.isDirectory()) {
            try {
                // Note: to create a file:// URL, one would typically use something like
                // f.toURI().toURL().toString(). However this generates a broken path on
                // Windows, namely "C:\\foo" is converted to "file:/C:/foo" instead of
                // "file:///C:/foo" (i.e. there should be 3 / after "file:"). So we'll
                // do the correct thing manually.

                String path = f.getAbsolutePath();
                if (File.separatorChar != '/') {
                    path = path.replace(File.separatorChar, '/');
                }

                // For some reason the URL class doesn't add the mandatory "//" after
                // the "file:" protocol name, so it has to be hacked into the path.
                URL url = new URL("file", null, "//" + path);  //$NON-NLS-1$ //$NON-NLS-2$
                String result = url.toString();
                return result;
            } catch (MalformedURLException e) {
                // ignore malformed URLs
            }
        }

        return null;
    }

    /**
     * Parses the SDK add-ons to look for files called {@link SdkConstants#FN_DEVICES_XML} to
     * load {@link LayoutDevice} from them.
     */
    private void loadLayoutDevices() {
        IAndroidTarget[] targets = mManager.getTargets();
        for (IAndroidTarget target : targets) {
            if (target.isPlatform() == false) {
                File deviceXml = new File(target.getLocation(), SdkConstants.FN_DEVICES_XML);
                if (deviceXml.isFile()) {
                    mLayoutDeviceManager.parseAddOnLayoutDevice(deviceXml);
                }
            }
        }

        mLayoutDeviceManager.sealAddonLayoutDevices();
    }

    /**
     * Delegate listener for project changes.
     */
    private IProjectListener mProjectListener = new IProjectListener() {
        public void projectClosed(IProject project) {
            onProjectRemoved(project, false /*deleted*/);
        }

        public void projectDeleted(IProject project) {
            onProjectRemoved(project, true /*deleted*/);
        }

        private void onProjectRemoved(IProject project, boolean deleted) {
            // get the target project
            synchronized (sLock) {
                // Don't use getProject() as it could create the ProjectState if it's not
                // there yet and this is not what we want. We want the current object.
                // Therefore, direct access to the map.
                ProjectState state = sProjectStateMap.get(project);
                if (state != null) {
                    // 1. clear the layout lib cache associated with this project
                    IAndroidTarget target = state.getTarget();
                    if (target != null) {
                        // get the bridge for the target, and clear the cache for this project.
                        AndroidTargetData data = mTargetDataMap.get(target);
                        if (data != null) {
                            LayoutBridge bridge = data.getLayoutBridge();
                            if (bridge != null && bridge.status == LoadStatus.LOADED) {
                                bridge.bridge.clearCaches(project);
                            }
                        }
                    }

                    // 2. if the project is a library, make sure to update the
                    // LibraryState for any main project using this.
                    // Also, record the updated projects that are libraries, to update
                    // projects that depend on them.
                    ArrayList<ProjectState> updatedLibraries = new ArrayList<ProjectState>();
                    for (ProjectState projectState : sProjectStateMap.values()) {
                        LibraryState libState = projectState.getLibrary(project);
                        if (libState != null) {
                            // get the current libraries.
                            IProject[] oldLibraries = projectState.getFullLibraryProjects();

                            // the unlink below will work in the job, but we need to close
                            // the library right away.
                            // This is because in case of a rename of a project, projectClosed and
                            // projectOpened will be called before any other job is run, so we
                            // need to make sure projectOpened is closed with the main project
                            // state up to date.
                            libState.close();


                            // edit the project to remove the linked source folder.
                            // this also calls LibraryState.close();
                            LinkUpdateBundle bundle = getLinkBundle(projectState, oldLibraries);
                            if (bundle != null) {
                                queueLinkUpdateBundle(bundle);
                            }

                            if (projectState.isLibrary()) {
                                updatedLibraries.add(projectState);
                            }
                        }
                    }

                    if (deleted) {
                        // remove the linked path variable
                        disposeLibraryProject(project);
                    }

                    // now remove the project for the project map.
                    sProjectStateMap.remove(project);

                    // update the projects that depend on the updated project
                    updateProjectsWithNewLibraries(updatedLibraries);
                }
            }
        }

        public void projectOpened(IProject project) {
            onProjectOpened(project);
        }

        public void projectOpenedWithWorkspace(IProject project) {
            // no need to force recompilation when projects are opened with the workspace.
            onProjectOpened(project);
        }

        private void onProjectOpened(final IProject openedProject) {
            ProjectState openedState = getProjectState(openedProject);
            if (openedState != null) {
                if (openedState.hasLibraries()) {
                    // list of library to link to the opened project.
                    final ArrayList<IProject> libsToLink = new ArrayList<IProject>();

                    // Look for all other opened projects to see if any is a library for the opened
                    // project.
                    synchronized (sLock) {
                        for (ProjectState projectState : sProjectStateMap.values()) {
                            if (projectState != openedState) {
                                // ProjectState#needs() both checks if this is a missing library
                                // and updates LibraryState to contains the new values.
                                LibraryState libState = openedState.needs(projectState);

                                if (libState != null) {
                                    // we have a match! Add the library to the list (if it was
                                    // not added through an indirect dependency before).
                                    IProject libProject = libState.getProjectState().getProject();
                                    if (libsToLink.contains(libProject) == false) {
                                        libsToLink.add(libProject);
                                    }

                                    // now find what this depends on, and add it too.
                                    // The order here doesn't matter
                                    // as it's just to add the linked source folder, so there's no
                                    // need to use ProjectState#getFullLibraryProjects() which
                                    // could return project that have already been added anyway.
                                    fillProjectDependenciesList(libState.getProjectState(),
                                            libsToLink);
                                }
                            }
                        }
                    }

                    // create a link bundle always, because even if there's no libraries to add
                    // to the CPE, the cleaning of invalid CPE must happen.
                    LinkUpdateBundle bundle = new LinkUpdateBundle();
                    bundle.mProject = openedProject;
                    bundle.mNewLibraryProjects = libsToLink.toArray(
                            new IProject[libsToLink.size()]);
                    bundle.mCleanupCPE = true;
                    queueLinkUpdateBundle(bundle);
                }

                // if the project is a library, then add it to the list of projects being opened.
                // They will be processed in IResourceEventListener#resourceChangeEventEnd.
                // This is done so that we are sure to process all the projects being opened
                // first and only then process projects depending on the projects that were opened.
                if (openedState.isLibrary()) {
                    setupLibraryProject(openedProject);

                    mOpenedLibraryProjects.add(openedState);
                }
            }
        }

        public void projectRenamed(IProject project, IPath from) {
            System.out.println("RENAMED: " + project);
            // a project was renamed.
            // if the project is a library, look for any project that depended on it
            // and update it. (default.properties and linked source folder)
            ProjectState renamedState = getProjectState(project);
            if (renamedState.isLibrary()) {
                // remove the variable
                disposeLibraryProject(from.lastSegment());

                // update the project depending on the library
                synchronized (sLock) {
                    for (ProjectState projectState : sProjectStateMap.values()) {
                        if (projectState != renamedState && projectState.isMissingLibraries()) {
                            IPath oldRelativePath = makeRelativeTo(from,
                                    projectState.getProject().getFullPath());

                            IPath newRelativePath = makeRelativeTo(project.getFullPath(),
                                    projectState.getProject().getFullPath());

                            // get the current libraries
                            IProject[] oldLibraries = projectState.getFullLibraryProjects();

                            // update the library for the main project.
                            LibraryState libState = projectState.updateLibrary(
                                    oldRelativePath.toString(), newRelativePath.toString(),
                                    renamedState);
                            if (libState != null) {
                                // this project depended on the renamed library, create a bundle
                                // with the whole library difference (in case the renamed library
                                // also depends on libraries).

                                LinkUpdateBundle bundle = getLinkBundle(projectState,
                                        oldLibraries);
                                queueLinkUpdateBundle(bundle);

                                // add it to the opened projects to update whatever depends
                                // on it
                                if (projectState.isLibrary()) {
                                    mOpenedLibraryProjects.add(projectState);
                                }
                            }
                        }
                    }
                }
            }
        }
    };

    /**
     * Delegate listener for file changes.
     */
    private IFileListener mFileListener = new IFileListener() {
        public void fileChanged(final IFile file, IMarkerDelta[] markerDeltas, int kind) {
            if (SdkConstants.FN_DEFAULT_PROPERTIES.equals(file.getName()) &&
                    file.getParent() == file.getProject()) {
                try {
                    // reload the content of the default.properties file and update
                    // the target.
                    IProject iProject = file.getProject();
                    ProjectState state = Sdk.getProjectState(iProject);

                    // get the current target
                    IAndroidTarget oldTarget = state.getTarget();

                    // get the current library flag
                    boolean wasLibrary = state.isLibrary();

                    // get the current list of project dependencies
                    IProject[] oldLibraries = state.getFullLibraryProjects();

                    LibraryDifference diff = state.reloadProperties();

                    // load the (possibly new) target.
                    IAndroidTarget newTarget = loadTarget(state);

                    // check if this is a new library
                    if (state.isLibrary() && wasLibrary == false) {
                        setupLibraryProject(iProject);
                    }

                    // reload the libraries if needed
                    if (diff.hasDiff()) {
                        if (diff.added) {
                            synchronized (sLock) {
                                for (ProjectState projectState : sProjectStateMap.values()) {
                                    if (projectState != state) {
                                        // need to call needs to do the libraryState link,
                                        // but no need to look at the result, as we'll compare
                                        // the result of getFullLibraryProjects()
                                        // this is easier to due to indirect dependencies.
                                        state.needs(projectState);
                                    }
                                }
                            }
                        }

                        // and build the real difference. A list of new projects and a list of
                        // removed project.
                        // This is not the same as the added/removed libraries because libraries
                        // could be indirect dependencies through several different direct
                        // dependencies so it's easier to compare the full lists before and after
                        // the reload.
                        LinkUpdateBundle bundle = getLinkBundle(state, oldLibraries);
                        if (bundle != null) {
                            queueLinkUpdateBundle(bundle);
                        }
                    }

                    // apply the new target if needed.
                    if (newTarget != oldTarget) {
                        IJavaProject javaProject = BaseProjectHelper.getJavaProject(
                                file.getProject());
                        if (javaProject != null) {
                            AndroidClasspathContainerInitializer.updateProjects(
                                    new IJavaProject[] { javaProject });
                        }

                        // update the editors to reload with the new target
                        AdtPlugin.getDefault().updateTargetListeners(iProject);
                    }
                } catch (CoreException e) {
                    // This can't happen as it's only for closed project (or non existing)
                    // but in that case we can't get a fileChanged on this file.
                }
            }
        }
    };

    /** List of opened project. This is filled in {@link IProjectListener#projectOpened(IProject)}
     * and {@link IProjectListener#projectOpenedWithWorkspace(IProject)}, and processed in
     * {@link IResourceEventListener#resourceChangeEventEnd()}.
     */
    private final ArrayList<ProjectState> mOpenedLibraryProjects = new ArrayList<ProjectState>();

    /**
     * Delegate listener for resource changes. This is called before and after any calls to the
     * project and file listeners (for a given resource change event).
     */
    private IResourceEventListener mResourceEventListener = new IResourceEventListener() {
        public void resourceChangeEventStart() {
            // pass
        }

        public void resourceChangeEventEnd() {
            updateProjectsWithNewLibraries(mOpenedLibraryProjects);
            mOpenedLibraryProjects.clear();
        }
    };

    /**
     * Action bundle to update library links on a project.
     *
     * @see Sdk#queueLinkUpdateBundle(LinkUpdateBundle)
     * @see Sdk#updateLibraryLinks(LinkUpdateBundle, IProgressMonitor)
     */
    private static class LinkUpdateBundle {

        /** The main project receiving the library links. */
        IProject mProject = null;
        /** A list (possibly null/empty) of projects that should be linked. */
        IProject[] mNewLibraryProjects = null;
        /** an optional old library path that needs to be removed at the same time as the new
         * libraries are added. Can be <code>null</code> in which case no libraries are removed. */
        IPath mDeletedLibraryPath = null;
        /** A list (possibly null/empty) of projects that should be unlinked */
        IProject[] mRemovedLibraryProjects = null;
        /** Whether unknown IClasspathEntry (that were flagged as being added by ADT) are to be
         * removed. This is typically only set to <code>true</code> when the project is opened. */
        boolean mCleanupCPE = false;

        @Override
        public String toString() {
            return String.format(
                    "LinkUpdateBundle: %1$s (clean: %2$s) > added: %3$s, removed: %4$s, deleted: %5$s", //$NON-NLS-1$
                    mProject.getName(),
                    mCleanupCPE,
                    Arrays.toString(mNewLibraryProjects),
                    Arrays.toString(mRemovedLibraryProjects),
                    mDeletedLibraryPath);
        }
    }

    private final ArrayList<LinkUpdateBundle> mLinkActionBundleQueue =
            new ArrayList<LinkUpdateBundle>();

    /**
     * Queues a {@link LinkUpdateBundle} bundle to be run by a job.
     *
     * All action bundles are executed in a job in the exact order they are added.
     * This is convenient when several actions must be executed in a job consecutively (instead
     * of in parallel as it would happen if each started its own job) but it is impossible
     * to manually control the job that's running them (for instance each action is started from
     * different callbacks such as {@link IProjectListener#projectOpened(IProject)}.
     *
     * If the job is not yet started, or has terminated due to lack of action bundle, it is
     * restarted.
     *
     * @param bundle the action bundle to execute
     */
    private void queueLinkUpdateBundle(LinkUpdateBundle bundle) {
        boolean startJob = false;
        synchronized (mLinkActionBundleQueue) {
            startJob = mLinkActionBundleQueue.size() == 0;
            mLinkActionBundleQueue.add(bundle);
        }

        if (startJob) {
            Job job = new Job("Android Library Update") { //$NON-NLS-1$
                @Override
                protected IStatus run(IProgressMonitor monitor) {
                    // loop until there's no bundle to process
                    while (true) {
                        // get the bundle, but don't remove until we're done, or a new job could be
                        // started.
                        LinkUpdateBundle bundle = null;
                        synchronized (mLinkActionBundleQueue) {
                            // there is always a bundle at this point, as they are only removed
                            // at the end of this method, and the job is only started after adding
                            // one
                            bundle = mLinkActionBundleQueue.get(0);
                        }

                        // process the bundle.
                        try {
                            updateLibraryLinks(bundle, monitor);
                        } catch (Exception e) {
                            AdtPlugin.log(e, "Failed to process bundle: %1$s", //$NON-NLS-1$
                                    bundle.toString());
                        }

                        try {
                            // force a recompile
                            bundle.mProject.build(IncrementalProjectBuilder.FULL_BUILD, monitor);
                        } catch (Exception e) {
                            // no need to log those.
                        }

                        // remove it from the list.
                        synchronized (mLinkActionBundleQueue) {
                            mLinkActionBundleQueue.remove(0);

                            // no more bundle to process? done.
                            if (mLinkActionBundleQueue.size() == 0) {
                                return Status.OK_STATUS;
                            }
                        }
                    }
                }
            };
            job.setPriority(Job.BUILD);
            job.schedule();
        }
    }


    /**
     * Adds to a list the resolved {@link IProject} dependencies for a given {@link ProjectState}.
     * This recursively goes down to indirect dependencies.
     *
     * <strong>The list is filled in an order that is not valid for calling <code>aapt</code>
     * </strong>.
     * Use {@link ProjectState#getFullLibraryProjects()} for use with <code>aapt</code>.
     *
     * @param projectState the ProjectState of the project from which to add the libraries.
     * @param libraries the list of {@link IProject} to fill.
     */
    private void fillProjectDependenciesList(ProjectState projectState,
            ArrayList<IProject> libraries) {
        for (LibraryState libState : projectState.getLibraries()) {
            ProjectState libProjectState = libState.getProjectState();

            // only care if the LibraryState has a resolved ProjectState
            if (libProjectState != null) {
                // try not to add duplicate. This can happen if a project depends on 2 different
                // libraries that both depend on the same one.
                IProject libProject = libProjectState.getProject();
                if (libraries.contains(libProject) == false) {
                    libraries.add(libProject);
                }

                // process the libraries of this library too.
                fillProjectDependenciesList(libProjectState, libraries);
            }
        }
    }

    /**
     * Sets up a path variable for a given project.
     * The name of the variable is based on the name of the project. However some valid character
     * for project names can be invalid for variable paths.
     * {@link #getLibraryVariableName(String)} return the name of the variable based on the
     * project name.
     *
     * @param libProject the project
     *
     * @see IPathVariableManager
     * @see #getLibraryVariableName(String)
     */
    private void setupLibraryProject(IProject libProject) {
        // if needed add a path var for this library
        IPathVariableManager pathVarMgr =
            ResourcesPlugin.getWorkspace().getPathVariableManager();
        IPath libPath = libProject.getLocation();

        final String varName = getLibraryVariableName(libProject.getName());

        if (libPath.equals(pathVarMgr.getValue(varName)) == false) {
            try {
                pathVarMgr.setValue(varName, libPath);
            } catch (CoreException e) {
                AdtPlugin.logAndPrintError(e, "Library Project",
                        "Unable to set linked path var '%1$s' for library %2$s: %3$s", //$NON-NLS-1$
                        varName, libPath.toOSString(), e.getMessage());
            }
        }
    }


    /**
     * Deletes the path variable that was setup for the given project.
     * @param project the project
     * @see #disposeLibraryProject(String)
     */
    private void disposeLibraryProject(IProject project) {
        disposeLibraryProject(project.getName());
    }

    /**
     * Deletes the path variable that was setup for the given project name.
     * The name of the variable is based on the name of the project. However some valid character
     * for project names can be invalid for variable paths.
     * {@link #getLibraryVariableName(String)} return the name of the variable based on the
     * project name.
     * @param projectName the name of the project, unmodified.
     */
    private void disposeLibraryProject(String projectName) {
        IPathVariableManager pathVarMgr =
            ResourcesPlugin.getWorkspace().getPathVariableManager();

        final String varName = getLibraryVariableName(projectName);

        // remove the value by setting the value to null.
        try {
            pathVarMgr.setValue(varName, null /*path*/);
        } catch (CoreException e) {
            String message = String.format("Unable to remove linked path var '%1$s'", //$NON-NLS-1$
                    varName);
            AdtPlugin.log(e, message);
        }
    }

    /**
     * Returns a valid path variable name based on the name of a library project.
     * @param name the name of the library project.
     */
    private String getLibraryVariableName(String name) {
        return "_android_" + name.replaceAll("-", "_"); //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$
    }

    /**
     * Update the library links for a project
     *
     * This does the follow:
     * - add/remove the library projects to the main projects dynamic reference list. This is used
     *   by the builders to receive resource change deltas for library projects and figure out what
     *   needs to be recompiled/recreated.
     * - create new {@link IClasspathEntry} of type {@link IClasspathEntry#CPE_SOURCE} for each
     *   source folder for each new library project.
     * - remove the {@link IClasspathEntry} of type {@link IClasspathEntry#CPE_SOURCE} for each
     *   source folder for each removed library project.
     * - If {@link LinkUpdateBundle#mCleanupCPE} is set to true, all CPE created by ADT that cannot
     *   be resolved are removed. This should only be used when the project is opened.
     *
     * <strong>This must not be called directly. Instead the {@link LinkUpdateBundle} must
     * be run through a job with {@link #queueLinkUpdateBundle(LinkUpdateBundle)}.</strong>
     *
     * @param bundle The {@link LinkUpdateBundle} action bundle that contains all the parameters
     *               necessary to execute the action.
     * @param monitor an {@link IProgressMonitor}.
     * @return an {@link IStatus} with the status of the action.
     */
    private IStatus updateLibraryLinks(LinkUpdateBundle bundle, IProgressMonitor monitor) {
        if (bundle.mProject.isOpen() == false) {
            return Status.OK_STATUS;
        }
        try {
            // add the library to the list of dynamic references. This is necessary to receive
            // notifications that the library content changed in the builders.
            IProjectDescription projectDescription = bundle.mProject.getDescription();
            IProject[] refs = projectDescription.getDynamicReferences();

            if (refs.length > 0) {
                ArrayList<IProject> list = new ArrayList<IProject>(Arrays.asList(refs));

                // remove a previous library if needed (in case of a rename)
                if (bundle.mDeletedLibraryPath != null) {
                    // since project basically have only one segment that matter,
                    // just check the names
                    removeFromList(list, bundle.mDeletedLibraryPath.lastSegment());
                }

                if (bundle.mRemovedLibraryProjects != null) {
                    for (IProject removedProject : bundle.mRemovedLibraryProjects) {
                        removeFromList(list, removedProject.getName());
                    }
                }

                // add the new ones if they don't exist
                if (bundle.mNewLibraryProjects != null) {
                    for (IProject newProject : bundle.mNewLibraryProjects) {
                        if (list.contains(newProject) == false) {
                            list.add(newProject);
                        }
                    }
                }

                // set the changed list
                projectDescription.setDynamicReferences(
                        list.toArray(new IProject[list.size()]));
            } else {
                if (bundle.mNewLibraryProjects != null) {
                    projectDescription.setDynamicReferences(bundle.mNewLibraryProjects);
                }
            }

            // get the current classpath entries for the project to add the new source
            // folders.
            IJavaProject javaProject = JavaCore.create(bundle.mProject);
            IClasspathEntry[] entries = javaProject.getRawClasspath();
            ArrayList<IClasspathEntry> classpathEntries = new ArrayList<IClasspathEntry>(
                    Arrays.asList(entries));

            IWorkspaceRoot wsRoot = ResourcesPlugin.getWorkspace().getRoot();

            // loop on the classpath entries and look for CPE_SOURCE entries that
            // are linked folders, then record them for comparison later as we add the new
            // ones.
            ArrayList<IClasspathEntry> cpeToRemove = new ArrayList<IClasspathEntry>();
            for (IClasspathEntry classpathEntry : classpathEntries) {
                if (classpathEntry.getEntryKind() == IClasspathEntry.CPE_SOURCE) {
                    IPath path = classpathEntry.getPath();
                    IResource linkedRes = wsRoot.findMember(path);
                    if (linkedRes != null && linkedRes.isLinked() &&
                            CREATOR_ADT.equals(ProjectHelper.loadStringProperty(
                                    linkedRes, PROP_CREATOR))) {

                        // add always to list if we're doing clean-up
                        if (bundle.mCleanupCPE) {
                            cpeToRemove.add(classpathEntry);
                        } else {
                            String libName = ProjectHelper.loadStringProperty(linkedRes,
                                    PROP_LIBRARY_NAME);
                            if (libName != null && isRemovedLibrary(bundle, libName)) {
                                cpeToRemove.add(classpathEntry);
                            }
                        }
                    }
                }
            }

            // loop on the projects to add.
            if (bundle.mNewLibraryProjects != null) {
                for (IProject library : bundle.mNewLibraryProjects) {
                    if (library.isOpen() == false) {
                        continue;
                    }
                    final String libName = library.getName();
                    final String varName = getLibraryVariableName(libName);

                    // get the list of source folders for the library.
                    ArrayList<IPath> sourceFolderPaths = BaseProjectHelper.getSourceClasspaths(
                            library);

                    // loop on all the source folder, ignoring FD_GEN and add them
                    // as linked folder
                    for (IPath sourceFolderPath : sourceFolderPaths) {
                        IResource sourceFolder = wsRoot.findMember(sourceFolderPath);
                        if (sourceFolder == null || sourceFolder.isLinked()) {
                            continue;
                        }

                        IPath relativePath = sourceFolder.getProjectRelativePath();
                        if (SdkConstants.FD_GEN_SOURCES.equals(relativePath.toString())) {
                            continue;
                        }

                        // create the linked path
                        IPath linkedPath = new Path(varName).append(relativePath);

                        // look for an existing CPE that has the same linked path and that was
                        // going to be removed.
                        IClasspathEntry match = findClasspathEntryMatch(cpeToRemove, linkedPath,
                                null);

                        if (match == null) {
                            // no match, create one
                            // get a string version, to make up the linked folder name
                            String srcFolderName = relativePath.toString().replace(
                                    "/",  //$NON-NLS-1$
                                    "_"); //$NON-NLS-1$

                            // folder name
                            String folderName = libName + "_" + srcFolderName; //$NON-NLS-1$

                            // create a linked resource for the library using the path var.
                            IFolder libSrc = bundle.mProject.getFolder(folderName);
                            IPath libSrcPath = libSrc.getFullPath();

                            // check if there's a CPE that would conflict, in which case it needs to
                            // be removed (this can happen for existing CPE that don't match an open
                            // project)
                            match = findClasspathEntryMatch(classpathEntries, null/*rawPath*/,
                                    libSrcPath);
                            if (match != null) {
                                classpathEntries.remove(match);
                            }

                            // the path of the linked resource is based on the path variable
                            // representing the library project, followed by the source folder name.
                            libSrc.createLink(linkedPath, IResource.REPLACE, monitor);

                            // set some persistent properties on it to know that it was
                            // created by ADT.
                            ProjectHelper.saveStringProperty(libSrc, PROP_CREATOR, CREATOR_ADT);
                            ProjectHelper.saveResourceProperty(libSrc, PROP_LIBRARY, library);
                            ProjectHelper.saveStringProperty(libSrc, PROP_LIBRARY_NAME,
                                    library.getName());

                            // add the source folder to the classpath entries
                            classpathEntries.add(JavaCore.newSourceEntry(libSrcPath));
                        } else {
                            // there's a valid match, do nothing, but remove the match from
                            // the list of previously existing CPE.
                            cpeToRemove.remove(match);
                        }
                    }
                }
            }

            // remove the CPE that should be removed.
            classpathEntries.removeAll(cpeToRemove);

            // set the new list
            javaProject.setRawClasspath(
                    classpathEntries.toArray(new IClasspathEntry[classpathEntries.size()]),
                    monitor);

            // and delete the folders of the CPE that were removed (must be done after)
            for (IClasspathEntry cpe : cpeToRemove) {
                IResource res = wsRoot.findMember(cpe.getPath());
                res.delete(true, monitor);
            }

            return Status.OK_STATUS;
        } catch (CoreException e) {
            AdtPlugin.logAndPrintError(e, bundle.mProject.getName(),
                    "Failed to create library links: %1$s", //$NON-NLS-1$
                    e.getMessage());
            return e.getStatus();
        }
    }

    private boolean isRemovedLibrary(LinkUpdateBundle bundle, String libName) {
        if (bundle.mDeletedLibraryPath != null &&
                libName.equals(bundle.mDeletedLibraryPath.lastSegment())) {
            return true;
        }

        if (bundle.mRemovedLibraryProjects != null) {
            for (IProject removedProject : bundle.mRemovedLibraryProjects) {
                if (libName.equals(removedProject.getName())) {
                    return true;
                }
            }
        }

        return false;
    }

    /**
     * Computes the library difference based on a previous list and a current state, and creates
     * a {@link LinkUpdateBundle} action to update the given project.
     * @param project The current project state
     * @param oldLibraries the list of old libraries. Typically the result of
     *            {@link ProjectState#getFullLibraryProjects()} before the ProjectState is updated.
     * @return null if there no action to take, or a {@link LinkUpdateBundle} object to run.
     */
    private LinkUpdateBundle getLinkBundle(ProjectState project, IProject[] oldLibraries) {
        // get the new full list of projects
        IProject[] newLibraries = project.getFullLibraryProjects();

        // and build the real difference. A list of new projects and a list of
        // removed project.
        // This is not the same as the added/removed libraries because libraries
        // could be indirect dependencies through several different direct
        // dependencies so it's easier to compare the full lists before and after
        // the reload.

        List<IProject> addedLibs = new ArrayList<IProject>();
        List<IProject> removedLibs = new ArrayList<IProject>();

        // first get the list of new projects.
        for (IProject newLibrary : newLibraries) {
            boolean found = false;
            for (IProject oldLibrary : oldLibraries) {
                if (newLibrary.equals(oldLibrary)) {
                    found = true;
                    break;
                }
            }

            // if it was not found in the old libraries, it's really new
            if (found == false) {
                addedLibs.add(newLibrary);
            }
        }

        // now the list of removed projects.
        for (IProject oldLibrary : oldLibraries) {
            boolean found = false;
            for (IProject newLibrary : newLibraries) {
                if (newLibrary.equals(oldLibrary)) {
                    found = true;
                    break;
                }
            }

            // if it was not found in the new libraries, it's really been removed
            if (found == false) {
                removedLibs.add(oldLibrary);
            }
        }

        if (addedLibs.size() > 0 || removedLibs.size() > 0) {
            LinkUpdateBundle bundle = new LinkUpdateBundle();
            bundle.mProject = project.getProject();
            bundle.mNewLibraryProjects =
                addedLibs.toArray(new IProject[addedLibs.size()]);
            bundle.mRemovedLibraryProjects =
                removedLibs.toArray(new IProject[removedLibs.size()]);
            return bundle;
        }

        return null;
    }

    /**
     * Removes a project from a list based on its name.
     * @param projects the list of projects.
     * @param name the name of the project to remove.
     */
    private void removeFromList(List<IProject> projects, String name) {
        final int count = projects.size();
        for (int i = 0 ; i < count ; i++) {
            // since project basically have only one segment that matter,
            // just check the names
            if (projects.get(i).getName().equals(name)) {
                projects.remove(i);
                return;
            }
        }
    }

    /**
     * Returns a {@link IClasspathEntry} from the given list whose linked path match the given path.
     * @param cpeList a list of {@link IClasspathEntry} of {@link IClasspathEntry#getEntryKind()}
     *                {@link IClasspathEntry#CPE_SOURCE} whose {@link IClasspathEntry#getPath()}
     *                points to a linked folder.
     * @param rawPath the raw path to compare to. Can be null if <var>path</var> is used instead.
     * @param path the path to compare to. Can be null if <var>rawPath</var> is used instead.
     * @return the matching IClasspathEntry or null.
     */
    private IClasspathEntry findClasspathEntryMatch(ArrayList<IClasspathEntry> cpeList,
            IPath rawPath, IPath path) {
        IWorkspaceRoot wsRoot = ResourcesPlugin.getWorkspace().getRoot();
        for (IClasspathEntry cpe : cpeList) {
            IPath cpePath = cpe.getPath();
            // test the normal path of the resource.
            if (path != null && path.equals(cpePath)) {
                return cpe;
            }

            IResource res = wsRoot.findMember(cpePath);
            // getRawLocation returns the path that the linked folder points to.
            if (rawPath != null && res.getRawLocation().equals(rawPath)) {
                return cpe;
            }

        }
        return null;
    }

    /**
     * Updates all existing projects with a given list of new/updated libraries.
     * This loops through all opened projects and check if they depend on any of the given
     * library project, and if they do, they are linked together.
     * @param libraries the list of new/updated library projects.
     */
    private void updateProjectsWithNewLibraries(List<ProjectState> libraries) {
        if (libraries.size() == 0) {
            return;
        }

        ArrayList<ProjectState> updatedLibraries = new ArrayList<ProjectState>();
        synchronized (sLock) {
            // for each projects, look for projects that depend on it, and update them.
            // Once they are updated (meaning ProjectState#needs() has been called on them),
            // we add them to the list so that can be updated as well.
            for (ProjectState projectState : sProjectStateMap.values()) {
                // record the current library dependencies
                IProject[] oldLibraries = projectState.getFullLibraryProjects();

                boolean needLibraryDependenciesUpdated = false;
                for (ProjectState library : libraries) {
                    // Normally we would only need to test if ProjectState#needs returns non null,
                    // meaning the link between the project and the library has not been
                    // done yet.
                    // However what matters here is that the library is a dependency,
                    // period. If the library project was updated, then we redo the link,
                    // with all indirect dependencies (which *have* changed, since this is
                    // what this method is all about.)
                    // We still need to call ProjectState#needs to make the link in case it's not
                    // been done yet (which can happen if the library project was just opened).
                    if (projectState != library) {
                        // call needs in case this new library was just opened, and the link needs
                        // to be done
                        LibraryState libState = projectState.needs(library);
                        if (libState == null && projectState.dependsOn(library)) {
                            // ProjectState.needs only returns true if the library was needed.
                            // but we also need to check the case where the project depends on
                            // the library but the link was already done.
                            needLibraryDependenciesUpdated = true;
                        }
                    }
                }

                if (needLibraryDependenciesUpdated) {
                    projectState.updateFullLibraryList();
                }

                LinkUpdateBundle bundle = getLinkBundle(projectState, oldLibraries);
                if (bundle != null) {
                    queueLinkUpdateBundle(bundle);

                    // if this updated project is a library, add it to the list, so that
                    // projects depending on it get updated too.
                    if (projectState.isLibrary() &&
                            updatedLibraries.contains(projectState) == false) {
                        updatedLibraries.add(projectState);
                    }
                }
            }
        }

        // done, but there may be updated projects that were libraries, so we need to do the same
        // for this libraries, to update the project there were depending on.
        updateProjectsWithNewLibraries(updatedLibraries);
    }

    /**
     * Computes a new IPath targeting a given target, but relative to a given base.
     * <p/>{@link IPath#makeRelativeTo(IPath, IPath)} is only available in 3.5 and later.
     * <p/>This is based on the implementation {@link Path#makeRelativeTo(IPath)}.
     * @param target the target of the IPath
     * @param base the IPath to base the relative path on.
     * @return the relative IPath
     */
    public static IPath makeRelativeTo(IPath target, IPath base) {
        //can't make relative if devices are not equal
        if (target.getDevice() != base.getDevice() && (target.getDevice() == null ||
                !target.getDevice().equalsIgnoreCase(base.getDevice())))
            return target;
        int commonLength = target.matchingFirstSegments(base);
        final int differenceLength = base.segmentCount() - commonLength;
        final int newSegmentLength = differenceLength + target.segmentCount() - commonLength;
        if (newSegmentLength == 0)
            return Path.EMPTY;
        String[] newSegments = new String[newSegmentLength];
        //add parent references for each segment different from the base
        Arrays.fill(newSegments, 0, differenceLength, ".."); //$NON-NLS-1$
        //append the segments of this path not in common with the base
        System.arraycopy(target.segments(), commonLength, newSegments,
                differenceLength, newSegmentLength - differenceLength);

        StringBuilder sb = new StringBuilder();
        for (String s : newSegments) {
            sb.append(s).append('/');
        }

        return new Path(null, sb.toString());
    }
}