* Copyright (C) 2008, 2012 Marek Zawirski <marek.zawirski@gmail.com> 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

*******************************************************************************/

* This class provides universal panel for editing list of {@link RefSpec} -

* specifications for both push or fetch, depending on panel configuration.

* <p>

* It is intended to allow user easily edit specifications, supporting user with

* content assistant and giving feedback with error information as soon as

* possible. Component uses editable specifications table and panels for easy

* creation of new specifications basing on typical push/fetch schemes (like

* branch update, deletion, all branches update, saved configuration etc.).

* <p>

* The model of specifications list behind panel is accessible by public methods

* - giving both read and write access. Listener interface for handling changes

* in model is provided by {@link SelectionChangeListener}.

* <p>

* Typical class usage:

*

* <pre>

* // create panel for editing push-specifications

* RefSpecPanel panel = new RefSpecPanel(parent, true);

* // register model listener

* panel.addRefSpecPanelListener(listener);

*

* // provide information about local and remote refs

* panel.setRefsData(localRepo, remoteRefs, remoteName);

*

* // get result data

* List&lt;RefSpec&gt; result = panel.getRefSpecs();

* // further processing: push or save configuration...

* </pre>

*

* @see SelectionChangeListener

*/

  private static final String IMAGE_ADD = "ADD"; //$NON-NLS-1$

  private static final String IMAGE_DELETE = "DELETE"; //$NON-NLS-1$

  private static final String IMAGE_TRASH = "TRASH"; //$NON-NLS-1$

  private static final String IMAGE_CLEAR = "CLEAR"; //$NON-NLS-1$

  private static final int TABLE_PREFERRED_HEIGHT = 165;

  private static final int TABLE_PREFERRED_WIDTH = 560;

  private static final int COLUMN_MODE_WEIGHT = 23;

  private static final int COLUMN_SRC_WEIGHT = 40;

  private static final int COLUMN_DST_WEIGHT = 40;

  private static final int COLUMN_FORCE_WEIGHT = 30;

  private static final int COLUMN_REMOVE_WEIGHT = 20;

  private static boolean isDeleteRefSpec(final Object element) {

    return ((RefSpec) element).getSource() == null;

  }

  private static boolean isValidRefExpression(final String s) {

    if (RefSpec.isWildcard(s)) {

      // replace wildcard with some legal name just for checking

      return isValidRefExpression(s.substring(0, s.length() - 1) + 'X');

    } else

      return Repository.isValidRefName(s)

          || Repository.isValidRefName(Constants.R_HEADS + s)

          || Repository.isValidRefName(Constants.R_TAGS + s);

  }

  private static RefSpec setRefSpecSource(final RefSpec spec, final String src) {

    final String dst;

    if (RefSpec.isWildcard(src))

      dst = wildcardSpecComponent(spec.getDestination());

    else

      dst = unwildcardSpecComponent(spec.getDestination(), src);

    return spec.setSourceDestination(src, dst);

  }

  private static RefSpec setRefSpecDestination(final RefSpec spec,

      final String dst) {

    final String src;

    if (RefSpec.isWildcard(dst))

      src = wildcardSpecComponent(spec.getSource());

    else

      src = unwildcardSpecComponent(spec.getSource(), dst);

    return spec.setSourceDestination(src, dst);

  }

  private static String wildcardSpecComponent(final String comp) {

    final int i;

    if (RefSpec.isWildcard(comp))

      return comp;

    if (comp == null || (i = comp.lastIndexOf('/')) == -1) {

      // That's somewhat ugly. What better can we do here?

      return UIText.RefSpecPanel_refChooseSomeWildcard;

    }

    return comp.substring(0, i + 1) + '*';

  }

  private static String unwildcardSpecComponent(final String comp,

      final String other) {

    if (!RefSpec.isWildcard(comp))

      return comp;

    if (other == null || other.length() == 0)

      return ""; //$NON-NLS-1$

    final int i = other.lastIndexOf('/');

    return comp.substring(0, comp.length() - 1) + other.substring(i + 1);

  }

  private static List<RefContentProposal> createProposalsFilteredRemote(

      final List<RefContentProposal> proposals) {

    final List<RefContentProposal> result = new ArrayList<RefContentProposal>();

    for (final RefContentProposal p : proposals) {

      final String content = p.getContent();

      if (content.equals(Constants.HEAD)

          || content.startsWith(Constants.R_HEADS))

        result.add(p);

    }

    return result;

  }

  private static Image getDecorationImage(final String key) {

    return FieldDecorationRegistry.getDefault().getFieldDecoration(key)

        .getImage();

  }

  private static void setControlDecoration(final ControlDecoration control,

      final String imageKey, final String description) {

    control.setImage(getDecorationImage(imageKey));

    control.setDescriptionText(description);

    control.show();

  }

  private final List<RefSpec> specs = new ArrayList<RefSpec>();

  private final Composite panel;

  private TableViewer tableViewer;

  private CellEditor modeCellEditor;

  private CellEditor localRefCellEditor;

  private CellEditor remoteRefCellEditor;

  private CellEditor forceUpdateCellEditor;

  private CellEditor removeSpecCellEditor;

  private int srcColumnIndex;

  private Button removeAllSpecButton;

  private Button forceUpdateAllButton;

  private Button creationButton;

  private Button addConfiguredButton;

  private Button addTagsButton;

  private Button addBranchesButton;

  private ControlDecoration creationSrcDecoration;

  private ControlDecoration creationDstDecoration;

  private ControlDecoration deleteRefDecoration;

  private Combo creationSrcCombo;

  private Combo creationDstCombo;

  private Combo deleteRefCombo;

  private Button deleteButton;

  private Repository localDb;

  private RemoteConfig remoteConfig;

  private Set<String> localRefNames = Collections.emptySet();

  private Set<String> remoteRefNames = Collections.emptySet();

  private List<RefSpec> predefinedConfigured = Collections.emptyList();

  private RefSpec predefinedBranches = null;

  private final RefContentProposalProvider remoteProposalProvider;

  private final RefContentProposalProvider localProposalProvider;

  private ComboLabelingSupport creationSrcComboSupport;

  private ComboLabelingSupport creationDstComboSupport;

  private ComboLabelingSupport deleteRefComboSupport;

  private final boolean pushSpecs;

  private final List<SelectionChangeListener> listeners = new LinkedList<SelectionChangeListener>();

  private final ImageRegistry imageRegistry;

  private boolean matchingAnyRefs;

  private RefSpec invalidSpec;

  private RefSpec invalidSpecSameDst;

  private String errorMessage;

  private Color errorBackgroundColor;

  private Color errorTextColor;

  /**

   * Create a new panel and install it on a provided composite. Panel is

   * created either for editing push or fetch specifications - this setting

   * can't be changed later, after constructing object.

   * <p>

   * Panel is created with an empty model, with no provided assistant. It

   * can't be used by user until

   * {@link #setAssistanceData(Repository, Collection, RemoteConfig)} method is

   * called, and to this time is disabled.

   *

   * @param parent

   *            parent control for panel.

   * @param pushSpecs

   *            true if panel is used for editing push specifications, false

   *            if panel is used for editing fetch specifications.

   */

  public RefSpecPanel(final Composite parent, final boolean pushSpecs) {

    this.pushSpecs = pushSpecs;

    this.localProposalProvider = new RefContentProposalProvider(pushSpecs);

    this.remoteProposalProvider = new RefContentProposalProvider(false);

    this.imageRegistry = new ImageRegistry(parent.getDisplay());

    panel = new Composite(parent, SWT.NONE);

    panel.setLayout(new GridLayout());

    safeCreateResources();

    createCreationPanel();

    if (pushSpecs)

      createDeleteCreationPanel();

    createPredefinedCreationPanel();

    createTableGroup();

    addRefSpecTableListener(new SelectionChangeListener() {

      public void selectionChanged() {

        validateSpecs();

      }

    });

    setEnable(false);

  }

  /**

   * Enable or disable panel controls.

   *

   * @param enable

   *            true to enable panel, false to disable.

   */

  public void setEnable(final boolean enable) {

    getControl().setEnabled(enable);

  }

  /**

   * Set information needed for assisting user with entering data and

   * validating user input. This method automatically enables the panel.

   *

   * @param localRepo

   *            local repository where specifications will be applied.

   * @param remoteRefs

   *            collection of remote refs as advertised by remote repository.

   *            Typically they are collected by {@link FetchConnection}

   *            implementation.

   * @param config

   */

  public void setAssistanceData(final Repository localRepo,

      final Collection<Ref> remoteRefs, RemoteConfig config) {

    this.localDb = localRepo;

        this.remoteConfig = config;

    final List<RefContentProposal> remoteProposals = createContentProposals(

        remoteRefs, null);

    remoteProposalProvider.setProposals(remoteProposals);

    remoteRefNames = new HashSet<String>();

    for (final RefContentProposal p : remoteProposals)

      remoteRefNames.add(p.getContent());

    Ref HEAD = null;

    try {

      HEAD = localDb.getRef(Constants.HEAD);

    } catch (IOException e) {

      Activator.logError("Couldn't read HEAD from local repository", e); //$NON-NLS-1$

    }

    final List<RefContentProposal> localProposals = createContentProposals(

        localDb.getAllRefs().values(), HEAD);

    localProposalProvider.setProposals(localProposals);

    localRefNames = new HashSet<String>();

    for (final RefContentProposal ref : localProposals)

      localRefNames.add(ref.getContent());

    final List<RefContentProposal> localFilteredProposals = createProposalsFilteredLocal(localProposals);

    final List<RefContentProposal> remoteFilteredProposals = createProposalsFilteredRemote(remoteProposals);

    if (pushSpecs) {

      creationSrcComboSupport.setProposals(localFilteredProposals);

      creationDstComboSupport.setProposals(remoteFilteredProposals);

    } else {

      creationSrcComboSupport.setProposals(remoteFilteredProposals);

      creationDstComboSupport.setProposals(localFilteredProposals);

    }

    validateCreationPanel();

    if (pushSpecs) {

      deleteRefComboSupport.setProposals(remoteFilteredProposals);

      validateDeleteCreationPanel();

    }

    if (remoteConfig == null)

      predefinedConfigured = Collections.emptyList();

    else {

      if (pushSpecs)

        predefinedConfigured = remoteConfig.getPushRefSpecs();

      else

        predefinedConfigured = remoteConfig.getFetchRefSpecs();

      for (final RefSpec spec : predefinedConfigured)

        addRefSpec(spec);

    }

    updateAddPredefinedButton(addConfiguredButton, predefinedConfigured);

    if (pushSpecs)

      predefinedBranches = Transport.REFSPEC_PUSH_ALL;

    else {

      final String r;

      if (remoteConfig == null)

        r = UIText.RefSpecPanel_refChooseRemoteName;

      else

        r = remoteConfig.getName();

      predefinedBranches = new RefSpec("refs/heads/*:refs/remotes/" //$NON-NLS-1$

          + r + "/*"); //$NON-NLS-1$

    }

    updateAddPredefinedButton(addBranchesButton, predefinedBranches);

    setEnable(true);

  }

  /**

   * @return underlying control for this panel.

   */

  public Control getControl() {

    return panel;

  }

  /**

   * Return current list of specifications of this panel.

   * <p>

   * This method should be called only from the UI thread.

   *

   * @return unmodifiable view of specifications list as edited by user in

   *         this panel. Note that this view underlying model may change -

   *         create a copy if needed.

   */

  public List<RefSpec> getRefSpecs() {

    return Collections.unmodifiableList(specs);

  }

  /**

   * @return true if specifications list is empty, false otherwise.

   */

  public boolean isEmpty() {

    return getRefSpecs().isEmpty();

  }

  /**

   * @return true if specifications match any ref(s) in source repository -

   *         resolve to concrete ref updates, false otherwise. For non empty

   *         specifications list, false value is possible only in case of

   *         specifications with wildcards.

   */

  public boolean isMatchingAnyRefs() {

    return matchingAnyRefs;

  }

  /**

   * Add provided specification to this panel. Panel view is automatically

   * refreshed, model is revalidated.

   * <p>

   * Note that the same reference can't be added twice to the panel, while two

   * or more equals RefSpec (in terms of equals method) can be - likely

   * causing validation error.

   * <p>

   * This method should be called only from the UI thread.

   *

   * @param spec

   *            specification to add.

   * @throws IllegalArgumentException

   *             if specification with same reference already exists in panel.

   */

  public void addRefSpec(final RefSpec spec) {

    final int i = indexOfSpec(spec);

    if (i != -1)

      throw new IllegalArgumentException("RefSpec " + spec //$NON-NLS-1$

          + " already exists."); //$NON-NLS-1$

    specs.add(spec);

    tableViewer.add(spec);

    notifySpecsChanged();

  }

  /**

   * Remove provided specification from this panel. Panel view is

   * automatically refreshed, model is revalidated.

   * <p>

   * Provided specification must be equals with existing one in terms of

   * reference equality, not an equals method.

   * <p>

   * This method should be called only from the UI thread.

   *

   * @param spec

   *            specification to remove.

   * @throws IllegalArgumentException

   *             if specification with this reference doesn't exist in this

   *             panel.

   */

  public void removeRefSpec(final RefSpec spec) {

    final int i = indexOfSpec(spec);

    if (i == -1)

      throw new IllegalArgumentException("RefSpec " + spec //$NON-NLS-1$

          + " not found."); //$NON-NLS-1$

    specs.remove(i);

    tableViewer.remove(spec);

    notifySpecsChanged();

  }

  /**

   * Change some specification to the new one.

   * <p>

   * Old specification must exist in the panel, while new specification can't

   * exist before (both in terms of reference equality).

   * <p>

   * This method should be called only from the UI thread.

   *

   * @param oldSpec

   *            specification to change. Can't be null.

   * @param newSpec

   *            new specification to override existing one. Can't be null.

   */

  public void setRefSpec(final RefSpec oldSpec, final RefSpec newSpec) {

    final int oldI = indexOfSpec(oldSpec);

    if (oldI == -1)

      throw new IllegalArgumentException("RefSpec " + oldSpec //$NON-NLS-1$

          + " not found."); //$NON-NLS-1$

    final int newI = indexOfSpec(newSpec);

    if (newI != -1)

      throw new IllegalArgumentException("RefSpec " + newSpec //$NON-NLS-1$

          + " already exists."); //$NON-NLS-1$

    specs.set(oldI, newSpec);

    // have to refresh whole table as we are operating on immutable objects

    // (this shouldn't be an issue)

    tableViewer.refresh();

    notifySpecsChanged();

  }

  /**

   * Clear all specifications from this panel.

   * <p>

   * This method should be called only from the UI thread.

   */

  public void clearRefSpecs() {

    final RefSpec toRemove[] = specs.toArray(new RefSpec[0]);

    specs.clear();

    tableViewer.remove(toRemove);

    notifySpecsChanged();

  }

  /**

   * Add listener of changes in panel model.

   * <p>

   * Listeners are notified on events caused by both operations invoked by

   * external calls and user interaction. Listener method(s) is always called

   * from UI thread and shouldn't perform long computations.

   * <p>

   * Order of adding listeners is significant. This method is not thread-safe.

   * Listeners should be set up before panel usage.

   *

   * @param listener

   *            listener to add.

   */

  public void addRefSpecTableListener(final SelectionChangeListener listener) {

    listeners.add(listener);

  }

  /**

   * Get user-friendly error message regarding invalid specification.

   *

   * @return user-readable information about invalid specification.

   */

  public String getErrorMessage() {

    return errorMessage;

  }

  /**

   * Return information about validity of specifications.

   * <p>

   * Specifications are considered valid if pushing/fetching (depending on

   * panel configuration) shouldn't cause any error except for

   * non-fast-forward or server-related errors complaint. I.e. specifications

   * destinations don't overlap and every specification is correctly

   * formulated, preferably none is referring to non-existing ref etc.

   *

   * @return true if all specifications in panel are valid, false if at least

   *         one specification is invalid (in this case

   *         {@link #getErrorMessage()} gives detailed information for user).

   */

  public boolean isValid() {

    return errorMessage == null;

  }

  private int indexOfSpec(final RefSpec spec) {

    int i;

    for (i = 0; i < specs.size(); i++) {

      // we have to compare references, not use List#indexOf,

      // as equals is implemented in RefSpec

      if (specs.get(i) == spec)

        break;

    }

    if (i == specs.size())

      return -1;

    return i;

  }

  private void notifySpecsChanged() {

    for (final SelectionChangeListener listener : listeners)

      listener.selectionChanged();

  }

  private void safeCreateResources() {

    imageRegistry.put(IMAGE_ADD, UIIcons.ELCL16_ADD);

    imageRegistry.put(IMAGE_DELETE, UIIcons.ELCL16_DELETE);

    imageRegistry.put(IMAGE_TRASH, UIIcons.ELCL16_TRASH);

    imageRegistry.put(IMAGE_CLEAR, UIIcons.ELCL16_CLEAR);

    errorBackgroundColor = new Color(panel.getDisplay(), 255, 150, 150);

    errorTextColor = new Color(panel.getDisplay(), 255, 0, 0);

    panel.addDisposeListener(new DisposeListener() {

      public void widgetDisposed(DisposeEvent e) {

        imageRegistry.dispose();

        errorBackgroundColor.dispose();

        errorTextColor.dispose();

      }

    });

  }

  private RefContentProposalProvider getRefsProposalProvider(

      final boolean local) {

    return (local ? localProposalProvider : remoteProposalProvider);

  }

  private void createCreationPanel() {

    final Group creationPanel = new Group(panel, SWT.NONE);

    creationPanel.setText(UIText.RefSpecPanel_creationGroup);

    creationPanel.setLayoutData(new GridData(SWT.FILL, SWT.FILL, true,

        false));

    final GridLayout layout = new GridLayout();

    layout.numColumns = 3;

    layout.horizontalSpacing = 10;

    layout.verticalSpacing = 2;

    creationPanel.setLayout(layout);

    new Label(creationPanel, SWT.NONE)

        .setText(UIText.RefSpecPanel_creationSrc);

    new Label(creationPanel, SWT.NONE)

        .setText(UIText.RefSpecPanel_creationDst);

    creationButton = new Button(creationPanel, SWT.PUSH);

    creationButton.setLayoutData(new GridData(SWT.RIGHT, SWT.BOTTOM, false,

        false, 1, 2));

    creationButton.setImage(imageRegistry.get(IMAGE_ADD));

    creationButton.setText(UIText.RefSpecPanel_creationButton);

    creationButton.addSelectionListener(new SelectionAdapter() {

      @Override

      public void widgetSelected(SelectionEvent e) {

        final String src = creationSrcComboSupport.getContent();

        final String dst = creationDstComboSupport.getContent();

        RefSpec spec = new RefSpec(src + ':' + dst);

        addRefSpec(spec);

        creationSrcCombo.setText(""); //$NON-NLS-1$

        creationDstCombo.setText(""); //$NON-NLS-1$

      }

    });

    creationButton.setToolTipText(NLS.bind(

        UIText.RefSpecPanel_creationButtonDescription, typeString()));

    creationSrcDecoration = createAssistedDecoratedCombo(creationPanel,

        getRefsProposalProvider(pushSpecs),

        new IContentProposalListener() {

          public void proposalAccepted(IContentProposal proposal) {

            tryAutoCompleteSrcToDst();

          }

        });

    creationSrcCombo = (Combo) creationSrcDecoration.getControl();

    creationSrcCombo.setLayoutData(new GridData(SWT.FILL, SWT.CENTER, true,

        false));

    creationSrcCombo.addTraverseListener(new TraverseListener() {

      public void keyTraversed(TraverseEvent e) {

        // SWT.TRAVERSE_RETURN may be also reasonable here, but

        // it can be confused with RETURN for content proposal

        if (e.detail == SWT.TRAVERSE_TAB_NEXT)

          tryAutoCompleteSrcToDst();

      }

    });

    if (pushSpecs)

      creationSrcCombo

          .setToolTipText(UIText.RefSpecPanel_srcPushDescription);

    else

      creationSrcCombo

          .setToolTipText(UIText.RefSpecPanel_srcFetchDescription);

    creationSrcComboSupport = new ComboLabelingSupport(creationSrcCombo,

        new SelectionAdapter() {

          @Override

          public void widgetSelected(SelectionEvent e) {

            tryAutoCompleteSrcToDst();

          }

        });

    creationDstDecoration = createAssistedDecoratedCombo(creationPanel,

        getRefsProposalProvider(!pushSpecs),

        new IContentProposalListener() {

          public void proposalAccepted(IContentProposal proposal) {

            tryAutoCompleteDstToSrc();

          }

        });

    creationDstCombo = (Combo) creationDstDecoration.getControl();

    creationDstCombo.setLayoutData(new GridData(SWT.FILL, SWT.CENTER, true,

        false));

    creationDstCombo.addTraverseListener(new TraverseListener() {

      public void keyTraversed(TraverseEvent e) {

        // SWT.TRAVERSE_RETURN may be also reasonable here, but

        // it can be confused with RETURN for content proposal

        if (e.detail == SWT.TRAVERSE_TAB_NEXT)

          tryAutoCompleteDstToSrc();

      }

    });

    if (pushSpecs)

      creationDstCombo

          .setToolTipText(UIText.RefSpecPanel_dstPushDescription);

    else

      creationDstCombo

          .setToolTipText(UIText.RefSpecPanel_dstFetchDescription);

    creationDstComboSupport = new ComboLabelingSupport(creationDstCombo,

        new SelectionAdapter() {

          @Override

          public void widgetSelected(SelectionEvent e) {

            tryAutoCompleteDstToSrc();

          }

        });

    validateCreationPanel();

    final ModifyListener validator = new ModifyListener() {

      public void modifyText(final ModifyEvent e) {

        validateCreationPanel();

      }

    };

    creationSrcCombo.addModifyListener(validator);

    creationDstCombo.addModifyListener(validator);

  }

  private void createDeleteCreationPanel() {

    final Group deletePanel = new Group(panel, SWT.NONE);

    deletePanel.setText(UIText.RefSpecPanel_deletionGroup);

    deletePanel

        .setLayoutData(new GridData(SWT.FILL, SWT.FILL, true, false));

    final GridLayout layout = new GridLayout();

    layout.numColumns = 3;

    layout.horizontalSpacing = 10;

    deletePanel.setLayout(layout);

    final Label label = new Label(deletePanel, SWT.NONE);

    label.setText(UIText.RefSpecPanel_deletionRef);

    label.setLayoutData(new GridData(SWT.RIGHT, SWT.CENTER, false, false));

    deleteRefDecoration = createAssistedDecoratedCombo(deletePanel,

        getRefsProposalProvider(false), null);

    deleteRefCombo = (Combo) deleteRefDecoration.getControl();

    deleteRefCombo.setLayoutData(new GridData(SWT.FILL, SWT.CENTER, true,

        false));

    deleteRefCombo

        .setToolTipText(UIText.RefSpecPanel_dstDeletionDescription);

    deleteRefComboSupport = new ComboLabelingSupport(deleteRefCombo, null);

    deleteButton = new Button(deletePanel, SWT.PUSH);

    deleteButton.setLayoutData(new GridData(SWT.RIGHT, SWT.CENTER, false,

        false));

    deleteButton.setImage(imageRegistry.get(IMAGE_DELETE));

    deleteButton.setText(UIText.RefSpecPanel_deletionButton);

    deleteButton.addSelectionListener(new SelectionAdapter() {

      @Override

      public void widgetSelected(SelectionEvent e) {

        RefSpec spec = new RefSpec(':' + deleteRefComboSupport.getContent());

        addRefSpec(spec);

        deleteRefCombo.setText(""); //$NON-NLS-1$

      }

    });

    deleteButton

        .setToolTipText(UIText.RefSpecPanel_deletionButtonDescription);

    validateDeleteCreationPanel();

    deleteRefCombo.addModifyListener(new ModifyListener() {

      public void modifyText(final ModifyEvent e) {

        validateDeleteCreationPanel();

      }

    });

  }

  private void createPredefinedCreationPanel() {

    final Group predefinedPanel = new Group(panel, SWT.NONE);

    predefinedPanel.setLayoutData(new GridData(SWT.FILL, SWT.FILL, true,

        false));

    predefinedPanel.setText(UIText.RefSpecPanel_predefinedGroup);

    final GridLayout layout = new GridLayout();

    layout.numColumns = 3;

    predefinedPanel.setLayout(layout);

    addConfiguredButton = new Button(predefinedPanel, SWT.PUSH);

    addConfiguredButton.setLayoutData(new GridData(SWT.FILL, SWT.CENTER,

        true, false));

    addConfiguredButton.setText(NLS.bind(

        UIText.RefSpecPanel_predefinedConfigured, typeStringTitle()));

    addConfiguredButton.addSelectionListener(new SelectionAdapter() {

      @Override

      public void widgetSelected(SelectionEvent e) {

        addPredefinedRefSpecs(predefinedConfigured);

      }

    });

    addConfiguredButton

        .setToolTipText(UIText.RefSpecPanel_predefinedConfiguredDescription);

    updateAddPredefinedButton(addConfiguredButton, predefinedConfigured);

    addBranchesButton = new Button(predefinedPanel, SWT.PUSH);

    addBranchesButton.setLayoutData(new GridData(SWT.FILL, SWT.CENTER,

        true, false));

    addBranchesButton.setText(UIText.RefSpecPanel_predefinedAll);

    addBranchesButton.addSelectionListener(new SelectionAdapter() {

      @Override

      public void widgetSelected(SelectionEvent e) {

        addPredefinedRefSpecs(predefinedBranches);

      }

    });

    addBranchesButton

        .setToolTipText(UIText.RefSpecPanel_predefinedAllDescription);

    updateAddPredefinedButton(addBranchesButton, predefinedBranches);

    addTagsButton = new Button(predefinedPanel, SWT.PUSH);

    addTagsButton.setLayoutData(new GridData(SWT.FILL, SWT.CENTER, true,

        false));

    addTagsButton.setText(UIText.RefSpecPanel_predefinedTags);

    addTagsButton.addSelectionListener(new SelectionAdapter() {

      @Override

      public void widgetSelected(SelectionEvent e) {

        addPredefinedRefSpecs(Transport.REFSPEC_TAGS);

      }

    });

    addTagsButton

        .setToolTipText(UIText.RefSpecPanel_predefinedTagsDescription);

    updateAddPredefinedButton(addTagsButton, Transport.REFSPEC_TAGS);

    addRefSpecTableListener(new SelectionChangeListener() {

      public void selectionChanged() {

        updateAddPredefinedButton(addConfiguredButton,

            predefinedConfigured);

        updateAddPredefinedButton(addBranchesButton, predefinedBranches);

        updateAddPredefinedButton(addTagsButton, Transport.REFSPEC_TAGS);

      }

    });

  }

  private ControlDecoration createAssistedDecoratedCombo(

      final Composite parent,

      final IContentProposalProvider proposalProvider,

      final IContentProposalListener listener) {

    // FIXME: VERY ANNOYING! reported as 243991 in eclipse bugzilla

    // when typing, pressing arrow-down key opens combo box drop-down

    // instead of moving within autocompletion list (Mac 10.4&10.5, Eclipse

    // 3.4)

    final Combo combo = new Combo(parent, SWT.DROP_DOWN);

    final ControlDecoration decoration = new ControlDecoration(combo,

        SWT.BOTTOM | SWT.LEFT);

    final ContentAssistCommandAdapter proposal = new ContentAssistCommandAdapter(

        combo, new ComboContentAdapter(), proposalProvider, null, null,

        true);

    proposal

        .setProposalAcceptanceStyle(ContentProposalAdapter.PROPOSAL_REPLACE);

    if (listener != null)

      proposal.addContentProposalListener(listener);

    return decoration;

  }

  private void createTableGroup() {

    final Group tableGroup = new Group(panel, SWT.NONE);

    tableGroup.setText(NLS.bind(UIText.RefSpecPanel_specifications,

        typeString()));

    tableGroup.setLayoutData(new GridData(SWT.FILL, SWT.FILL, true, true));

    tableGroup.setLayout(new GridLayout());

    createTable(tableGroup);

    createSpecsButtonsPanel(tableGroup);

  }

  private void createTable(final Group tableGroup) {

    final Composite tablePanel = new Composite(tableGroup, SWT.NONE);

    final GridData layoutData = new GridData(SWT.FILL, SWT.FILL, true, true);

    layoutData.heightHint = TABLE_PREFERRED_HEIGHT;

    layoutData.widthHint = TABLE_PREFERRED_WIDTH;

    tablePanel.setLayoutData(layoutData);

    tableViewer = new TableViewer(tablePanel, SWT.FULL_SELECTION

        | SWT.MULTI | SWT.BORDER | SWT.V_SCROLL);

    ColumnViewerToolTipSupport.enableFor(tableViewer);

    final Table table = tableViewer.getTable();

    table.setLinesVisible(true);

    table.setHeaderVisible(true);

    createTableColumns(tablePanel);

    createCellEditors(table);

    tableViewer.setContentProvider(new ArrayContentProvider());

    tableViewer.setInput(specs);

    tableViewer.setComparer(new IElementComparer() {

      public boolean equals(Object a, Object b) {

        // need that as viewers are not designed to support 2 equals

        // object, while we have RefSpec#equals implemented

        return a == b;

      }

      public int hashCode(Object element) {

        return element.hashCode();

      }

    });

  }

  private void createTableColumns(final Composite tablePanel) {

    final TableColumnLayout columnLayout = new TableColumnLayout();

    tablePanel.setLayout(columnLayout);

    createDummyColumn(columnLayout);

    if (pushSpecs)

      createModeColumn(columnLayout);

    createSrcColumn(columnLayout);

    createDstColumn(columnLayout);

    createForceColumn(columnLayout);

    createRemoveColumn(columnLayout);

  }

  private void createDummyColumn(final TableColumnLayout columnLayout) {

    final TableViewerColumn viewerColumn = new TableViewerColumn(

        tableViewer, SWT.LEFT);

    final TableColumn column = viewerColumn.getColumn();

    columnLayout.setColumnData(column, new ColumnWeightData(0, 0, false));

    viewerColumn.setLabelProvider(new ColumnLabelProvider());

    // FIXME: first cell is left aligned on Mac OS X 10.4, Eclipse 3.4

  }

  private void createModeColumn(final TableColumnLayout columnLayout) {

    final TableViewerColumn column = createColumn(columnLayout,

        UIText.RefSpecPanel_columnMode, COLUMN_MODE_WEIGHT, SWT.CENTER);

    column.setLabelProvider(new ColumnLabelProvider() {

      @Override

      public String getText(final Object element) {

        return (isDeleteRefSpec(element) ? UIText.RefSpecPanel_modeDelete

            : UIText.RefSpecPanel_modeUpdate);

      }

      @Override

      public Image getImage(Object element) {

        return (isDeleteRefSpec(element) ? imageRegistry

            .get(IMAGE_DELETE) : imageRegistry.get(IMAGE_ADD));

      }

      @Override

      public String getToolTipText(Object element) {

        if (isDeleteRefSpec(element))

          return UIText.RefSpecPanel_modeDeleteDescription + '\n'

              + UIText.RefSpecPanel_clickToChange;

        return UIText.RefSpecPanel_modeUpdateDescription + '\n'

            + UIText.RefSpecPanel_clickToChange;

      }

    });

    column.setEditingSupport(new EditingSupport(tableViewer) {

      @Override

      protected boolean canEdit(final Object element) {

        return true;

      }

      @Override

      protected CellEditor getCellEditor(final Object element) {

        return modeCellEditor;

      }

      @SuppressWarnings("boxing")

      @Override

      protected Object getValue(final Object element) {

        return isDeleteRefSpec(element);

      }

      @SuppressWarnings("boxing")

      @Override

      protected void setValue(final Object element, final Object value) {

        final RefSpec oldSpec = (RefSpec) element;

        final RefSpec newSpec;

        if ((Boolean) value) {

          newSpec = setRefSpecSource(oldSpec, null);

          setRefSpec(oldSpec, newSpec);

        } else {

          newSpec = setRefSpecSource(oldSpec,

              UIText.RefSpecPanel_refChooseSome);

          setRefSpec(oldSpec, newSpec);

          tableViewer.getControl().getDisplay().asyncExec(

              new Runnable() {

                public void run() {

                  tableViewer.editElement(newSpec,

                      srcColumnIndex);

                }

              });

        }

      }

    });

  }

  private void createSrcColumn(final TableColumnLayout columnLayout) {

    final TableViewerColumn column = createColumn(columnLayout,

        UIText.RefSpecPanel_columnSrc, COLUMN_SRC_WEIGHT, SWT.LEFT);

    column.setLabelProvider(new ColumnLabelProvider() {

      @Override

      public String getText(final Object element) {

        return ((RefSpec) element).getSource();

      }

      @Override

      public String getToolTipText(Object element) {

        if (isInvalidSpec(element))

          return errorMessage;

        if (isDeleteRefSpec(element))

          return UIText.RefSpecPanel_srcDeleteDescription;

        if (pushSpecs)

          return UIText.RefSpecPanel_srcPushDescription;

        return UIText.RefSpecPanel_srcFetchDescription;

      }

      @Override

      public Color getBackground(final Object element) {

        if (isInvalidSpec(element))

          return errorBackgroundColor;

        return null;

      }

      @Override

      public Color getToolTipForegroundColor(Object element) {

        if (isInvalidSpec(element))

          return errorTextColor;

        return null;

      }

    });

    column.setEditingSupport(new EditingSupport(tableViewer) {

      @Override

      protected boolean canEdit(final Object element) {

        return !isDeleteRefSpec(element);

      }

      @Override

      protected CellEditor getCellEditor(final Object element) {

        return (pushSpecs ? localRefCellEditor : remoteRefCellEditor);

      }

      @Override

      protected Object getValue(final Object element) {

        return ((RefSpec) element).getSource();

      }

      @Override

      protected void setValue(final Object element, final Object value) {

        if (value == null || ((String) value).length() == 0

            || ObjectId.zeroId().name().equals(value)) {

          // Ignore empty strings or null objects - do not set them in

          // model.User won't loose any information if we just fall

          // back to the old value.

          // If user want to delete ref, let change the mode.

          return;

        }

        final RefSpec oldSpec = (RefSpec) element;

        final RefSpec newSpec = setRefSpecSource(oldSpec,

            (String) value);

        setRefSpec(oldSpec, newSpec);

      }

    });

    // find index of this column - for later usage

    final TableColumn[] columns = tableViewer.getTable().getColumns();

    for (srcColumnIndex = 0; srcColumnIndex < columns.length; srcColumnIndex++)

      if (columns[srcColumnIndex] == column.getColumn())

        break;

  }

  private void createDstColumn(final TableColumnLayout columnLayout) {

    final TableViewerColumn column = createColumn(columnLayout,

        UIText.RefSpecPanel_columnDst, COLUMN_DST_WEIGHT, SWT.LEFT);

    column.setLabelProvider(new ColumnLabelProvider() {

      @Override

      public String getText(final Object element) {

        return ((RefSpec) element).getDestination();

      }

      @Override

      public String getToolTipText(Object element) {

        if (isInvalidSpec(element))

          return errorMessage;

        if (isDeleteRefSpec(element))

          return UIText.RefSpecPanel_dstDeletionDescription;

        if (pushSpecs)

          return UIText.RefSpecPanel_dstPushDescription;

        return UIText.RefSpecPanel_dstFetchDescription;

      }

      @Override

      public Color getBackground(final Object element) {

        if (isInvalidSpec(element))

          return errorBackgroundColor;

        return null;

      }

      @Override

      public Color getToolTipForegroundColor(Object element) {

        if (isInvalidSpec(element))

          return errorTextColor;

        return null;

      }

    });

    column.setEditingSupport(new EditingSupport(tableViewer) {

      @Override

      protected boolean canEdit(final Object element) {

        return true;

      }

      @Override

      protected CellEditor getCellEditor(final Object element) {

        return (pushSpecs ? remoteRefCellEditor : localRefCellEditor);

      }

      @Override

      protected Object getValue(final Object element) {

        return ((RefSpec) element).getDestination();

      }

      @Override

      protected void setValue(final Object element, final Object value) {

        if (value == null || ((String) value).length() == 0) {

          // Ignore empty strings - do not set them in model.

          // User won't loose any information if we just fall back

          // to the old value.

          return;

        }

        final RefSpec oldSpec = (RefSpec) element;

        final RefSpec newSpec = setRefSpecDestination(oldSpec,

            (String) value);

        setRefSpec(oldSpec, newSpec);

      }

    });

  }

  private void createForceColumn(final TableColumnLayout columnLayout) {