org.eclipse.egit.ui/src/org/eclipse/egit/ui/internal/branch/ProjectTrackerPreferenceHelper.java

   1 /*******************************************************************************
   2  * Copyright (C) 2018, Luís Copetti <lhcopetti@gmail.com>
   3  *
   4  * All rights reserved. This program and the accompanying materials
   5  * are made available under the terms of the Eclipse Public License 2.0
   6  * which accompanies this distribution, and is available at
   7  * https://www.eclipse.org/legal/epl-2.0/
   8  *
   9  * SPDX-License-Identifier: EPL-2.0
  10  *******************************************************************************/
  11 package org.eclipse.egit.ui.internal.branch;
  12
  13 import java.io.IOException;
  14 import java.io.StringReader;
  15 import java.io.StringWriter;
  16 import java.util.Collections;
  17 import java.util.List;
  18 import java.util.stream.Collectors;
  19 import java.util.stream.Stream;
  20
  21 import org.eclipse.egit.ui.Activator;
  22 import org.eclipse.jface.preference.IPreferenceStore;
  23 import org.eclipse.jgit.lib.Repository;
  24 import org.eclipse.jgit.util.StringUtils;
  25 import org.eclipse.ui.IMemento;
  26 import org.eclipse.ui.WorkbenchException;
  27 import org.eclipse.ui.XMLMemento;
  28
  29 /**
  30  * A helper class to simplify storing the association between project paths and
  31  * (repository + branch). This API prevents the user
  32  * {@link BranchProjectTracker} from knowing where these associations are being
  33  * saved. For this particular case at a {@link IPreferenceStore} using
  34  * {@link XMLMemento}.
  35  * <p>
  36  * The usual location for the file is at:
  37  * .metadata/.plugins/org.eclipse.core.runtime/.settings/org.eclipse.egit.ui.prefs
  38  * </p>
  39  * <p>
  40  * An example entry would be: {@code
  41  * //BranchProjectTracker__/absolute/path/to/git/repository/.git_BranchName=<?xml
  42  * version\="1.0"
  43  * encoding\="UTF-8"?>\n<projects>\n<project>/</project>\n</projects> }
  44  * </p>
  45  */
  46 class ProjectTrackerPreferenceHelper {
  47
  48         private static final String PREFIX = "BranchProjectTracker_"; //$NON-NLS-1$
  49
  50         private static final String KEY_PROJECTS = "projects"; //$NON-NLS-1$
  51
  52         private static final String KEY_PROJECT = "project"; //$NON-NLS-1$
  53
  54         /**
  55          * @param repo
  56          * @param branch
  57          * @param projects
  58          */
  59         static void saveToPreferences(Repository repo, String branch,
  60                         List<String> projects) {
  61                 XMLMemento preferencesMemento = createXMLMemento(projects);
  62                 String preferenceKey = getPreferenceKey(repo, branch);
  63                 saveToPreferenceStore(preferenceKey, preferencesMemento);
  64         }
  65
  66         private static XMLMemento createXMLMemento(List<String> projectPaths) {
  67                 XMLMemento memento = XMLMemento.createWriteRoot(KEY_PROJECTS);
  68                 projectPaths.forEach(path -> {
  69                         IMemento child = memento.createChild(KEY_PROJECT);
  70                         child.putTextData(path);
  71                 });
  72                 return memento;
  73         }
  74
  75         /**
  76          * Get preference key for branch. This will be unique to the repository and
  77          * branch.
  78          *
  79          * @param repo
  80          * @param branch
  81          * @return key
  82          */
  83         static String getPreferenceKey(Repository repo,
  84                         final String branch) {
  85                 return PREFIX + '_' + repo.getDirectory().getAbsolutePath() + '_'
  86                                 + branch;
  87         }
  88
  89         private static void saveToPreferenceStore(String key, XMLMemento content) {
  90                 IPreferenceStore store = Activator.getDefault().getPreferenceStore();
  91                 StringWriter writer = new StringWriter();
  92                 try {
  93                         content.save(writer);
  94                         store.setValue(key, writer.toString());
  95                 } catch (IOException e) {
  96                         Activator.logError("Error writing branch-project associations", e); //$NON-NLS-1$
  97                 }
  98         }
  99
 100         /**
 101          * Load the project paths associated with the currently checked out branch.
 102          * These paths will be relative to the supplied repository.
 103          *
 104          * @param repo
 105          * @param branch
 106          * @return non-null but possibly empty array of projects
 107          */
 108         static List<String> restoreFromPreferences(Repository repo,
 109                         String branch) {
 110                 String key = getPreferenceKey(repo, branch);
 111                 String value = Activator.getDefault().getPreferenceStore()
 112                                 .getString(key);
 113
 114                 if (value.isEmpty()) {
 115                         return Collections.emptyList();
 116                 }
 117                 XMLMemento memento;
 118                 try {
 119                         memento = XMLMemento.createReadRoot(new StringReader(value));
 120                 } catch (WorkbenchException e) {
 121                         Activator.logError("Error reading branch-project associations", e); //$NON-NLS-1$
 122                         return Collections.emptyList();
 123                 }
 124                 IMemento[] children = memento.getChildren(KEY_PROJECT);
 125                 if (children.length == 0) {
 126                         return Collections.emptyList();
 127                 }
 128                 List<String> projectPaths = Stream.of(children)
 129                                 .map(IMemento::getTextData)
 130                                 .filter(x -> !StringUtils.isEmptyOrNull(x))
 131                                 .collect(Collectors.toList());
 132                 return projectPaths;
 133         }
 134 }