org.eclipse.egit.ui/src/org/eclipse/egit/ui/internal/repository/CreateBranchPage.java - egit/egit - Git at Google

 /*******************************************************************************
  * Copyright (c) 2010, 2016 SAP AG and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License 2.0
  * which accompanies this distribution, and is available at
  * https://www.eclipse.org/legal/epl-2.0/
  *
  * SPDX-License-Identifier: EPL-2.0
  *
  * Contributors:
  *    Mathias Kinzler (SAP AG) - initial implementation
  *    Dariusz Luksza <dariusz@luksza.org>
  *    Steffen Pingel (Tasktop Technologies) - fixes for bug 352253
  *    Thomas Wolf <thomas.wolf@paranor.ch> - Bug 499482
  *    Wim Jongman <wim.jongman@remainsoftware.com> - Bug 509878
  *******************************************************************************/
 package org.eclipse.egit.ui.internal.repository;

 import java.io.IOException;
 import java.text.MessageFormat;
 import java.util.concurrent.atomic.AtomicReference;

 import org.eclipse.core.runtime.CoreException;
 import org.eclipse.core.runtime.IConfigurationElement;
 import org.eclipse.core.runtime.IExtensionRegistry;
 import org.eclipse.core.runtime.IProgressMonitor;
 import org.eclipse.core.runtime.IStatus;
 import org.eclipse.core.runtime.Platform;
 import org.eclipse.core.runtime.Status;
 import org.eclipse.core.runtime.SubMonitor;
 import org.eclipse.core.runtime.jobs.Job;
 import org.eclipse.egit.core.Activator;
 import org.eclipse.egit.core.RepositoryUtil;
 import org.eclipse.egit.core.internal.SafeRunnable;
 import org.eclipse.egit.core.internal.Utils;
 import org.eclipse.egit.core.op.CreateLocalBranchOperation;
 import org.eclipse.egit.ui.IBranchNameProvider;
 import org.eclipse.egit.ui.UIUtils;
 import org.eclipse.egit.ui.internal.UIIcons;
 import org.eclipse.egit.ui.internal.UIText;
 import org.eclipse.egit.ui.internal.ValidationUtils;
 import org.eclipse.egit.ui.internal.branch.BranchOperationUI;
 import org.eclipse.egit.ui.internal.components.BranchNameNormalizer;
 import org.eclipse.egit.ui.internal.components.UpstreamConfigComponent;
 import org.eclipse.egit.ui.internal.dialogs.AbstractBranchSelectionDialog;
 import org.eclipse.jface.dialogs.Dialog;
 import org.eclipse.jface.dialogs.IInputValidator;
 import org.eclipse.jface.dialogs.IMessageProvider;
 import org.eclipse.jface.layout.GridDataFactory;
 import org.eclipse.jface.resource.JFaceResources;
 import org.eclipse.jface.resource.LocalResourceManager;
 import org.eclipse.jface.window.Window;
 import org.eclipse.jface.wizard.WizardPage;
 import org.eclipse.jgit.lib.BranchConfig.BranchRebaseMode;
 import org.eclipse.jgit.lib.Constants;
 import org.eclipse.jgit.lib.Ref;
 import org.eclipse.jgit.lib.Repository;
 import org.eclipse.jgit.revwalk.RevCommit;
 import org.eclipse.swt.SWT;
 import org.eclipse.swt.custom.StyledText;
 import org.eclipse.swt.events.ModifyEvent;
 import org.eclipse.swt.events.ModifyListener;
 import org.eclipse.swt.events.SelectionAdapter;
 import org.eclipse.swt.events.SelectionEvent;
 import org.eclipse.swt.events.TraverseEvent;
 import org.eclipse.swt.events.TraverseListener;
 import org.eclipse.swt.graphics.Point;
 import org.eclipse.swt.layout.GridData;
 import org.eclipse.swt.layout.GridLayout;
 import org.eclipse.swt.widgets.Button;
 import org.eclipse.swt.widgets.Composite;
 import org.eclipse.swt.widgets.Label;
 import org.eclipse.swt.widgets.Shell;
 import org.eclipse.swt.widgets.Text;
 import org.eclipse.ui.progress.WorkbenchJob;

 /**
  * Allows to create a new local branch based on another branch or commit.
  * <p>
  * The source can be selected using a branch selection dialog.
  * <p>
  * The user can select a strategy for configuring "Pull". The default as read
  * from the repository's autosetupmerge and autosetuprebase configuration is
  * suggested initially.
  */
 class CreateBranchPage extends WizardPage {

 	private static final String BRANCH_NAME_PROVIDER_ID = "org.eclipse.egit.ui.branchNameProvider"; //$NON-NLS-1$

 	private Job validateJob;
 	/**
 	 * Get proposed target branch name for given source branch name
 	 *
 	 * @param sourceName
 	 * @return target name
 	 */
 	public String getProposedTargetName(String sourceName) {
 		if (sourceName == null)
 			return null;

 		if (sourceName.startsWith(Constants.R_REMOTES))
 			return myRepository.shortenRemoteBranchName(sourceName);

 		if (sourceName.startsWith(Constants.R_TAGS))
 			return sourceName.substring(Constants.R_TAGS.length()) + "-branch"; //$NON-NLS-1$

 		return ""; //$NON-NLS-1$
 	}

 	private final Repository myRepository;

 	private final IInputValidator myValidator;

 	private final String myBaseRef;

 	private final RevCommit myBaseCommit;

 	private Text nameText;

 	/**
 	 * Whether the contents of {@code nameText} is a suggestion or was entered by the user.
 	 */
 	private boolean nameIsSuggestion;

 	private Button checkout;

 	private BranchRebaseMode upstreamConfig;

 	private UpstreamConfigComponent upstreamConfigComponent;

 	private Label sourceIcon;

 	private StyledText sourceNameLabel;

 	private String sourceRefName = ""; //$NON-NLS-1$

 	private final LocalResourceManager resourceManager = new LocalResourceManager(
 			JFaceResources.getResources());

 	/**
 	 * Constructs this page.
 	 * <p>
 	 * If a base branch is provided, the drop down will be selected accordingly
 	 *
 	 * @param repo
 	 *            the repository
 	 * @param baseRef
 	 *            the branch or tag to base the new branch on, may be null
 	 */
 	public CreateBranchPage(Repository repo, Ref baseRef) {
 		super(CreateBranchPage.class.getName());
 		this.myRepository = repo;
 		if (baseRef != null) {
 			this.myBaseRef = baseRef.getName();
 		} else {
 			this.myBaseRef = null;
 		}
 		this.myBaseCommit = null;
 		this.myValidator = ValidationUtils.getRefNameInputValidator(
 				myRepository, Constants.R_HEADS, false);
 		if (baseRef != null) {
 			this.upstreamConfig = CreateLocalBranchOperation
 					.getDefaultUpstreamConfig(repo, baseRef.getName());
 		} else {
 			this.upstreamConfig = null;
 		}
 		setTitle(MessageFormat.format(UIText.CreateBranchPage_Title,
 				RepositoryUtil.INSTANCE.getRepositoryName(repo)));
 		setMessage(UIText.CreateBranchPage_ChooseBranchAndNameMessage);
 	}

 	/**
 	 * Constructs this page.
 	 * <p>
 	 * If a base branch is provided, the drop down will be selected accordingly
 	 *
 	 * @param repo
 	 *            the repository
 	 * @param baseCommit
 	 *            the commit to base the new branch on, may be null
 	 */
 	public CreateBranchPage(Repository repo, RevCommit baseCommit) {
 		super(CreateBranchPage.class.getName());
 		this.myRepository = repo;
 		this.myBaseRef = null;
 		this.myBaseCommit = baseCommit;
 		this.myValidator = ValidationUtils.getRefNameInputValidator(
 				myRepository, Constants.R_HEADS, false);
 		this.upstreamConfig = null;
 		setTitle(MessageFormat.format(UIText.CreateBranchPage_Title,
 				RepositoryUtil.INSTANCE.getRepositoryName(repo)));
 		setMessage(UIText.CreateBranchPage_ChooseNameMessage);
 	}

 	@Override
 	public void createControl(Composite parent) {
 		Composite main = new Composite(parent, SWT.NONE);
 		main.setLayout(new GridLayout(4, false));

 		Label sourceLabel = new Label(main, SWT.NONE);
 		sourceLabel.setText(UIText.CreateBranchPage_SourceLabel);
 		sourceLabel.setToolTipText(UIText.CreateBranchPage_SourceTooltip);

 		sourceIcon = new Label(main, SWT.NONE);
 		sourceIcon.setImage(UIIcons.getImage(resourceManager, UIIcons.BRANCH));
 		sourceIcon.setLayoutData(GridDataFactory.fillDefaults()
 				.align(SWT.END, SWT.CENTER).create());

 		sourceNameLabel = new StyledText(main, SWT.NONE);
 		sourceNameLabel.setBackground(main.getBackground());
 		sourceNameLabel.setEditable(false);
 		sourceNameLabel.setLayoutData(GridDataFactory.fillDefaults()
 				.align(SWT.FILL, SWT.CENTER)
 				.grab(true, false).create());

 		Button selectButton = new Button(main, SWT.NONE);
 		selectButton.setText(UIText.CreateBranchPage_SourceSelectButton);
 		selectButton.addSelectionListener(new SelectionAdapter() {
 			@Override
 			public void widgetSelected(SelectionEvent e) {
 				selectSource();
 			}
 		});
 		UIUtils.setButtonLayoutData(selectButton);

 		Label nameLabel = new Label(main, SWT.NONE);
 		nameLabel.setText(UIText.CreateBranchPage_BranchNameLabel);
 		nameLabel.setLayoutData(GridDataFactory.fillDefaults().span(1, 1)
 				.align(SWT.BEGINNING, SWT.CENTER).create());
 		nameLabel.setToolTipText(UIText.CreateBranchPage_BranchNameToolTip);

 		nameText = new Text(main, SWT.BORDER);
 		// give focus to the nameText if label is activated using the mnemonic
 		nameLabel.addTraverseListener(new TraverseListener() {
 			@Override
 			public void keyTraversed(TraverseEvent e) {
 				nameText.setFocus();
 			}
 		});

 		nameText.addModifyListener(new ModifyListener() {
 			@Override
 			public void modifyText(ModifyEvent e) {
 				nameIsSuggestion = false;
 			}
 		});
 		// enable testing with SWTBot
 		nameText.setData("org.eclipse.swtbot.widget.key", "BranchName"); //$NON-NLS-1$ //$NON-NLS-2$
 		GridDataFactory.fillDefaults().grab(true, false).span(3, 1)
 				.applyTo(nameText);

 		upstreamConfigComponent = new UpstreamConfigComponent(main, SWT.NONE);
 		GridDataFactory.fillDefaults().grab(true, false).span(4, 1)
 				.applyTo(upstreamConfigComponent.getContainer());

 		upstreamConfigComponent
 				.addUpstreamConfigSelectionListener((newConfig) -> {
 					upstreamConfig = newConfig;
 					checkPage();
 				});

 		boolean isBare = myRepository.isBare();
 		checkout = new Button(main, SWT.CHECK);
 		checkout.setText(UIText.CreateBranchPage_CheckoutButton);
 		// most of the time, we probably will check this out
 		// unless we have a bare repository which doesn't allow
 		// check out at all
 		checkout.setSelection(!isBare);
 		checkout.setEnabled(!isBare);
 		checkout.setVisible(!isBare);
 		GridDataFactory.fillDefaults().grab(true, false).span(3, 1).applyTo(
 				checkout);
 		checkout.addSelectionListener(new SelectionAdapter() {
 			@Override
 			public void widgetSelected(SelectionEvent e) {
 				checkPage();
 			}
 		});

 		createValidateJob();

 		Dialog.applyDialogFont(main);
 		setControl(main);

 		if (this.myBaseCommit != null)
 			setSourceCommit(this.myBaseCommit);
 		else if (myBaseRef != null)
 			setSourceRef(myBaseRef);

 		nameText.setFocus();
 		// add the listeners just now to avoid unneeded checkPage()
 		nameText.addModifyListener(e -> {
 			validateJob.cancel();
 			// Schedule without delay to ensure the job finishes before the user
 			// can use the Finish button of the wizard. Otherwise we would have
 			// to disable the Finish button, leading to flickering from job
 			// start to job finish.
 			validateJob.schedule();
 		});
 		BranchNameNormalizer normalizer = new BranchNameNormalizer(nameText);
 		normalizer.setVisible(false);
 	}

 	private void createValidateJob() {
 		validateJob = new WorkbenchJob("Validate branch name") {//$NON-NLS-1$
 			@Override
 			public IStatus runInUIThread(IProgressMonitor monitor) {
 				if (sourceNameLabel.isDisposed()) {
 					return Status.CANCEL_STATUS;
 				}
 				checkPage();
 				return Status.OK_STATUS;
 			}
 		};
 		validateJob.setSystem(true);
 	}

 	@Override
 	public void dispose() {
 		resourceManager.dispose();
 		if (validateJob != null) {
 			validateJob.cancel();
 		}
 	}

 	private void setSourceRef(String refName) {
 		String shortName = Repository.shortenRefName(refName);
 		sourceNameLabel.setText(shortName);
 		if (refName.startsWith(Constants.R_HEADS)
 				|| refName.startsWith(Constants.R_REMOTES))
 			sourceIcon.setImage(UIIcons.getImage(resourceManager,
 					UIIcons.BRANCH));
 		else if (refName.startsWith(Constants.R_TAGS))
 			sourceIcon.setImage(UIIcons.getImage(resourceManager, UIIcons.TAG));
 		else
 			sourceIcon.setImage(UIIcons.getImage(resourceManager,
 					UIIcons.CHANGESET));

 		sourceRefName = refName;

 		suggestBranchName(refName);
 		upstreamConfig = CreateLocalBranchOperation
 				.getDefaultUpstreamConfig(myRepository, refName);
 		updateUpstreamComponent();
 		checkPage();
 	}

 	private void setSourceCommit(RevCommit commit) {
 		sourceNameLabel.setText(Utils.getShortObjectId(commit));
 		sourceIcon.setImage(UIIcons
 				.getImage(resourceManager, UIIcons.CHANGESET));

 		sourceRefName = commit.name();

 		upstreamConfig = null;
 		updateUpstreamComponent();
 		checkPage();
 	}

 	private void selectSource() {
 		SourceSelectionDialog dialog = new SourceSelectionDialog(getShell(),
 				myRepository, sourceRefName);
 		int result = dialog.open();
 		if (result == Window.OK) {
 			String refName = dialog.getRefName();
 			setSourceRef(refName);
 			nameText.setFocus();
 		}
 	}

 	private void updateUpstreamComponent() {
 		upstreamConfigComponent.setUpstreamConfig(upstreamConfig);

 		boolean showUpstreamConfig = sourceRefName.startsWith(Constants.R_HEADS)
 				|| sourceRefName.startsWith(Constants.R_REMOTES);
 		Composite container = upstreamConfigComponent.getContainer();
 		GridData gd = (GridData) container.getLayoutData();
 		if (gd.exclude == showUpstreamConfig) {
 			gd.exclude = !showUpstreamConfig;
 			container.setVisible(showUpstreamConfig);
 			container.getParent().layout(true);
 			ensurePreferredHeight(getShell());
 		}
 	}

 	private void checkPage() {
 		try {
 			boolean basedOnLocalBranch = sourceRefName
 					.startsWith(Constants.R_HEADS);
 			if (basedOnLocalBranch && upstreamConfig != null) {
 				setMessage(UIText.CreateBranchPage_LocalBranchWarningMessage,
 						IMessageProvider.INFORMATION);
 			} else {
 				setMessage(UIText.CreateBranchPage_ChooseBranchAndNameMessage);
 			}

 			if (sourceRefName.length() == 0) {
 				setErrorMessage(UIText.CreateBranchPage_MissingSourceMessage);
 				return;
 			}
 			String message = this.myValidator.isValid(nameText.getText());
 			if (message != null) {
 				setErrorMessage(message);
 				return;
 			}

 			setErrorMessage(null);
 		} finally {
 			setPageComplete(getErrorMessage() == null
 					&& nameText.getText().length() > 0);
 		}
 	}

 	public String getBranchName() {
 		return nameText.getText();
 	}

 	public boolean checkoutNewBranch() {
 		return checkout.getSelection();
 	}

 	/**
 	 * @param newRefName
 	 * @param checkoutNewBranch
 	 * @param monitor
 	 * @throws CoreException
 	 * @throws IOException
 	 */
 	public void createBranch(String newRefName, boolean checkoutNewBranch,
 			IProgressMonitor monitor)
 			throws CoreException, IOException {
 		SubMonitor progress = SubMonitor.convert(monitor,
 				checkoutNewBranch ? 2 : 1);
 		progress.setTaskName(UIText.CreateBranchPage_CreatingBranchMessage);

 		final CreateLocalBranchOperation cbop;

 		if (myBaseCommit != null
 				&& this.sourceRefName.equals(myBaseCommit.name()))
 			cbop = new CreateLocalBranchOperation(myRepository, newRefName,
 					myBaseCommit);
 		else
 			cbop = new CreateLocalBranchOperation(myRepository, newRefName,
 					myRepository.findRef(this.sourceRefName),
 					upstreamConfig);

 		cbop.execute(progress.newChild(1));

 		if (checkoutNewBranch && !progress.isCanceled()) {
 			progress.setTaskName(UIText.CreateBranchPage_CheckingOutMessage);
 			BranchOperationUI.checkout(myRepository, Constants.R_HEADS + newRefName)
 					.run(progress.newChild(1));
 		}
 	}

 	private void suggestBranchName(String ref) {
 		if (nameText.getText().length() == 0 || nameIsSuggestion) {
 			String branchNameSuggestion = getBranchNameSuggestionFromProvider();
 			if (branchNameSuggestion == null)
 				branchNameSuggestion = getProposedTargetName(ref);

 			if (branchNameSuggestion != null) {
 				nameText.setText(branchNameSuggestion);
 				nameText.selectAll();
 				nameIsSuggestion = true;
 			}
 		}
 	}

 	private IBranchNameProvider getBranchNameProvider() {
 		IExtensionRegistry registry = Platform.getExtensionRegistry();
 		IConfigurationElement[] config = registry
 				.getConfigurationElementsFor(BRANCH_NAME_PROVIDER_ID);
 		if (config.length > 0) {
 			Object provider;
 			try {
 				provider = config[0].createExecutableExtension("class"); //$NON-NLS-1$
 				if (provider instanceof IBranchNameProvider)
 					return (IBranchNameProvider) provider;
 			} catch (Throwable e) {
 				Activator.logError(
 						UIText.CreateBranchPage_CreateBranchNameProviderFailed,
 						e);
 			}
 		}
 		return null;
 	}

 	private String getBranchNameSuggestionFromProvider() {
 		final AtomicReference<String> ref = new AtomicReference<>();
 		final IBranchNameProvider branchNameProvider = getBranchNameProvider();
 		if (branchNameProvider != null) {
 			SafeRunnable.run(() -> ref
 					.set(branchNameProvider.getBranchNameSuggestion()));
 		}
 		return ref.get();
 	}

 	private static void ensurePreferredHeight(Shell shell) {
 		int preferredHeight = shell.computeSize(SWT.DEFAULT, SWT.DEFAULT).y;
 		Point size = shell.getSize();
 		if (size.y < preferredHeight)
 			shell.setSize(size.x, preferredHeight);
 	}

 	private static class SourceSelectionDialog extends
 			AbstractBranchSelectionDialog {

 		public SourceSelectionDialog(Shell parentShell, Repository repository,
 				String refToMark) {
 			super(parentShell, repository, refToMark, SHOW_LOCAL_BRANCHES
 					| SHOW_REMOTE_BRANCHES | SHOW_TAGS | SHOW_REFERENCES
 					| SELECT_CURRENT_REF | EXPAND_LOCAL_BRANCHES_NODE
 					| EXPAND_REMOTE_BRANCHES_NODE);
 		}

 		@Override
 		protected void refNameSelected(String refName) {
 			setOkButtonEnabled(refName != null);
 		}

 		@Override
 		protected String getTitle() {
 			return UIText.CreateBranchPage_SourceSelectionDialogTitle;
 		}

 		@Override
 		protected String getMessageText() {
 			return UIText.CreateBranchPage_SourceSelectionDialogMessage;
 		}
 	}
 }
	/*******************************************************************************
	* Copyright (c) 2010, 2016 SAP AG and others.
	* All rights reserved. This program and the accompanying materials
	* are made available under the terms of the Eclipse Public License 2.0
	* which accompanies this distribution, and is available at
	* https://www.eclipse.org/legal/epl-2.0/
	*
	* SPDX-License-Identifier: EPL-2.0
	*
	* Contributors:
	* Mathias Kinzler (SAP AG) - initial implementation
	* Dariusz Luksza <dariusz@luksza.org>
	* Steffen Pingel (Tasktop Technologies) - fixes for bug 352253
	* Thomas Wolf <thomas.wolf@paranor.ch> - Bug 499482
	* Wim Jongman <wim.jongman@remainsoftware.com> - Bug 509878
	*******************************************************************************/
	package org.eclipse.egit.ui.internal.repository;

	import java.io.IOException;
	import java.text.MessageFormat;
	import java.util.concurrent.atomic.AtomicReference;

	import org.eclipse.core.runtime.CoreException;
	import org.eclipse.core.runtime.IConfigurationElement;
	import org.eclipse.core.runtime.IExtensionRegistry;
	import org.eclipse.core.runtime.IProgressMonitor;
	import org.eclipse.core.runtime.IStatus;
	import org.eclipse.core.runtime.Platform;
	import org.eclipse.core.runtime.Status;
	import org.eclipse.core.runtime.SubMonitor;
	import org.eclipse.core.runtime.jobs.Job;
	import org.eclipse.egit.core.Activator;
	import org.eclipse.egit.core.RepositoryUtil;
	import org.eclipse.egit.core.internal.SafeRunnable;
	import org.eclipse.egit.core.internal.Utils;
	import org.eclipse.egit.core.op.CreateLocalBranchOperation;
	import org.eclipse.egit.ui.IBranchNameProvider;
	import org.eclipse.egit.ui.UIUtils;
	import org.eclipse.egit.ui.internal.UIIcons;
	import org.eclipse.egit.ui.internal.UIText;
	import org.eclipse.egit.ui.internal.ValidationUtils;
	import org.eclipse.egit.ui.internal.branch.BranchOperationUI;
	import org.eclipse.egit.ui.internal.components.BranchNameNormalizer;
	import org.eclipse.egit.ui.internal.components.UpstreamConfigComponent;
	import org.eclipse.egit.ui.internal.dialogs.AbstractBranchSelectionDialog;
	import org.eclipse.jface.dialogs.Dialog;
	import org.eclipse.jface.dialogs.IInputValidator;
	import org.eclipse.jface.dialogs.IMessageProvider;
	import org.eclipse.jface.layout.GridDataFactory;
	import org.eclipse.jface.resource.JFaceResources;
	import org.eclipse.jface.resource.LocalResourceManager;
	import org.eclipse.jface.window.Window;
	import org.eclipse.jface.wizard.WizardPage;
	import org.eclipse.jgit.lib.BranchConfig.BranchRebaseMode;
	import org.eclipse.jgit.lib.Constants;
	import org.eclipse.jgit.lib.Ref;
	import org.eclipse.jgit.lib.Repository;
	import org.eclipse.jgit.revwalk.RevCommit;
	import org.eclipse.swt.SWT;
	import org.eclipse.swt.custom.StyledText;
	import org.eclipse.swt.events.ModifyEvent;
	import org.eclipse.swt.events.ModifyListener;
	import org.eclipse.swt.events.SelectionAdapter;
	import org.eclipse.swt.events.SelectionEvent;
	import org.eclipse.swt.events.TraverseEvent;
	import org.eclipse.swt.events.TraverseListener;
	import org.eclipse.swt.graphics.Point;
	import org.eclipse.swt.layout.GridData;
	import org.eclipse.swt.layout.GridLayout;
	import org.eclipse.swt.widgets.Button;
	import org.eclipse.swt.widgets.Composite;
	import org.eclipse.swt.widgets.Label;
	import org.eclipse.swt.widgets.Shell;
	import org.eclipse.swt.widgets.Text;
	import org.eclipse.ui.progress.WorkbenchJob;

	/**
	* Allows to create a new local branch based on another branch or commit.
	* <p>
	* The source can be selected using a branch selection dialog.
	* <p>
	* The user can select a strategy for configuring "Pull". The default as read
	* from the repository's autosetupmerge and autosetuprebase configuration is
	* suggested initially.
	*/
	class CreateBranchPage extends WizardPage {

	private static final String BRANCH_NAME_PROVIDER_ID = "org.eclipse.egit.ui.branchNameProvider"; //$NON-NLS-1$

	private Job validateJob;
	/**
	* Get proposed target branch name for given source branch name
	*
	* @param sourceName
	* @return target name
	*/
	public String getProposedTargetName(String sourceName) {
	if (sourceName == null)
	return null;

	if (sourceName.startsWith(Constants.R_REMOTES))
	return myRepository.shortenRemoteBranchName(sourceName);

	if (sourceName.startsWith(Constants.R_TAGS))
	return sourceName.substring(Constants.R_TAGS.length()) + "-branch"; //$NON-NLS-1$

	return ""; //$NON-NLS-1$
	}

	private final Repository myRepository;

	private final IInputValidator myValidator;

	private final String myBaseRef;

	private final RevCommit myBaseCommit;

	private Text nameText;

	/**
	* Whether the contents of {@code nameText} is a suggestion or was entered by the user.
	*/
	private boolean nameIsSuggestion;

	private Button checkout;

	private BranchRebaseMode upstreamConfig;

	private UpstreamConfigComponent upstreamConfigComponent;

	private Label sourceIcon;

	private StyledText sourceNameLabel;

	private String sourceRefName = ""; //$NON-NLS-1$

	private final LocalResourceManager resourceManager = new LocalResourceManager(
	JFaceResources.getResources());

	/**
	* Constructs this page.
	* <p>
	* If a base branch is provided, the drop down will be selected accordingly
	*
	* @param repo
	* the repository
	* @param baseRef
	* the branch or tag to base the new branch on, may be null
	*/
	public CreateBranchPage(Repository repo, Ref baseRef) {
	super(CreateBranchPage.class.getName());
	this.myRepository = repo;
	if (baseRef != null) {
	this.myBaseRef = baseRef.getName();
	} else {
	this.myBaseRef = null;
	}
	this.myBaseCommit = null;
	this.myValidator = ValidationUtils.getRefNameInputValidator(
	myRepository, Constants.R_HEADS, false);
	if (baseRef != null) {
	this.upstreamConfig = CreateLocalBranchOperation
	.getDefaultUpstreamConfig(repo, baseRef.getName());
	} else {
	this.upstreamConfig = null;
	}
	setTitle(MessageFormat.format(UIText.CreateBranchPage_Title,
	RepositoryUtil.INSTANCE.getRepositoryName(repo)));
	setMessage(UIText.CreateBranchPage_ChooseBranchAndNameMessage);
	}

	/**
	* Constructs this page.
	* <p>
	* If a base branch is provided, the drop down will be selected accordingly
	*
	* @param repo
	* the repository
	* @param baseCommit
	* the commit to base the new branch on, may be null
	*/
	public CreateBranchPage(Repository repo, RevCommit baseCommit) {
	super(CreateBranchPage.class.getName());
	this.myRepository = repo;
	this.myBaseRef = null;
	this.myBaseCommit = baseCommit;
	this.myValidator = ValidationUtils.getRefNameInputValidator(
	myRepository, Constants.R_HEADS, false);
	this.upstreamConfig = null;
	setTitle(MessageFormat.format(UIText.CreateBranchPage_Title,
	RepositoryUtil.INSTANCE.getRepositoryName(repo)));
	setMessage(UIText.CreateBranchPage_ChooseNameMessage);
	}

	@Override
	public void createControl(Composite parent) {
	Composite main = new Composite(parent, SWT.NONE);
	main.setLayout(new GridLayout(4, false));

	Label sourceLabel = new Label(main, SWT.NONE);
	sourceLabel.setText(UIText.CreateBranchPage_SourceLabel);
	sourceLabel.setToolTipText(UIText.CreateBranchPage_SourceTooltip);

	sourceIcon = new Label(main, SWT.NONE);
	sourceIcon.setImage(UIIcons.getImage(resourceManager, UIIcons.BRANCH));
	sourceIcon.setLayoutData(GridDataFactory.fillDefaults()
	.align(SWT.END, SWT.CENTER).create());

	sourceNameLabel = new StyledText(main, SWT.NONE);
	sourceNameLabel.setBackground(main.getBackground());
	sourceNameLabel.setEditable(false);
	sourceNameLabel.setLayoutData(GridDataFactory.fillDefaults()
	.align(SWT.FILL, SWT.CENTER)
	.grab(true, false).create());

	Button selectButton = new Button(main, SWT.NONE);
	selectButton.setText(UIText.CreateBranchPage_SourceSelectButton);
	selectButton.addSelectionListener(new SelectionAdapter() {
	@Override
	public void widgetSelected(SelectionEvent e) {
	selectSource();
	}
	});
	UIUtils.setButtonLayoutData(selectButton);

	Label nameLabel = new Label(main, SWT.NONE);
	nameLabel.setText(UIText.CreateBranchPage_BranchNameLabel);
	nameLabel.setLayoutData(GridDataFactory.fillDefaults().span(1, 1)
	.align(SWT.BEGINNING, SWT.CENTER).create());
	nameLabel.setToolTipText(UIText.CreateBranchPage_BranchNameToolTip);

	nameText = new Text(main, SWT.BORDER);
	// give focus to the nameText if label is activated using the mnemonic
	nameLabel.addTraverseListener(new TraverseListener() {
	@Override
	public void keyTraversed(TraverseEvent e) {
	nameText.setFocus();
	}
	});

	nameText.addModifyListener(new ModifyListener() {
	@Override
	public void modifyText(ModifyEvent e) {
	nameIsSuggestion = false;
	}
	});
	// enable testing with SWTBot
	nameText.setData("org.eclipse.swtbot.widget.key", "BranchName"); //$NON-NLS-1$ //$NON-NLS-2$
	GridDataFactory.fillDefaults().grab(true, false).span(3, 1)
	.applyTo(nameText);

	upstreamConfigComponent = new UpstreamConfigComponent(main, SWT.NONE);
	GridDataFactory.fillDefaults().grab(true, false).span(4, 1)
	.applyTo(upstreamConfigComponent.getContainer());

	upstreamConfigComponent
	.addUpstreamConfigSelectionListener((newConfig) -> {
	upstreamConfig = newConfig;
	checkPage();
	});

	boolean isBare = myRepository.isBare();
	checkout = new Button(main, SWT.CHECK);
	checkout.setText(UIText.CreateBranchPage_CheckoutButton);
	// most of the time, we probably will check this out
	// unless we have a bare repository which doesn't allow
	// check out at all
	checkout.setSelection(!isBare);
	checkout.setEnabled(!isBare);
	checkout.setVisible(!isBare);
	GridDataFactory.fillDefaults().grab(true, false).span(3, 1).applyTo(
	checkout);
	checkout.addSelectionListener(new SelectionAdapter() {
	@Override
	public void widgetSelected(SelectionEvent e) {
	checkPage();
	}
	});

	createValidateJob();

	Dialog.applyDialogFont(main);
	setControl(main);

	if (this.myBaseCommit != null)
	setSourceCommit(this.myBaseCommit);
	else if (myBaseRef != null)
	setSourceRef(myBaseRef);

	nameText.setFocus();
	// add the listeners just now to avoid unneeded checkPage()
	nameText.addModifyListener(e -> {
	validateJob.cancel();
	// Schedule without delay to ensure the job finishes before the user
	// can use the Finish button of the wizard. Otherwise we would have
	// to disable the Finish button, leading to flickering from job
	// start to job finish.
	validateJob.schedule();
	});
	BranchNameNormalizer normalizer = new BranchNameNormalizer(nameText);
	normalizer.setVisible(false);
	}

	private void createValidateJob() {
	validateJob = new WorkbenchJob("Validate branch name") {//$NON-NLS-1$
	@Override
	public IStatus runInUIThread(IProgressMonitor monitor) {
	if (sourceNameLabel.isDisposed()) {
	return Status.CANCEL_STATUS;
	}
	checkPage();
	return Status.OK_STATUS;
	}
	};
	validateJob.setSystem(true);
	}

	@Override
	public void dispose() {
	resourceManager.dispose();
	if (validateJob != null) {
	validateJob.cancel();
	}
	}

	private void setSourceRef(String refName) {
	String shortName = Repository.shortenRefName(refName);
	sourceNameLabel.setText(shortName);
	if (refName.startsWith(Constants.R_HEADS)
	\|\| refName.startsWith(Constants.R_REMOTES))
	sourceIcon.setImage(UIIcons.getImage(resourceManager,
	UIIcons.BRANCH));
	else if (refName.startsWith(Constants.R_TAGS))
	sourceIcon.setImage(UIIcons.getImage(resourceManager, UIIcons.TAG));
	else
	sourceIcon.setImage(UIIcons.getImage(resourceManager,
	UIIcons.CHANGESET));

	sourceRefName = refName;

	suggestBranchName(refName);
	upstreamConfig = CreateLocalBranchOperation
	.getDefaultUpstreamConfig(myRepository, refName);
	updateUpstreamComponent();
	checkPage();
	}

	private void setSourceCommit(RevCommit commit) {
	sourceNameLabel.setText(Utils.getShortObjectId(commit));
	sourceIcon.setImage(UIIcons
	.getImage(resourceManager, UIIcons.CHANGESET));

	sourceRefName = commit.name();

	upstreamConfig = null;
	updateUpstreamComponent();
	checkPage();
	}

	private void selectSource() {
	SourceSelectionDialog dialog = new SourceSelectionDialog(getShell(),
	myRepository, sourceRefName);
	int result = dialog.open();
	if (result == Window.OK) {
	String refName = dialog.getRefName();
	setSourceRef(refName);
	nameText.setFocus();
	}
	}

	private void updateUpstreamComponent() {
	upstreamConfigComponent.setUpstreamConfig(upstreamConfig);

	boolean showUpstreamConfig = sourceRefName.startsWith(Constants.R_HEADS)
	\|\| sourceRefName.startsWith(Constants.R_REMOTES);
	Composite container = upstreamConfigComponent.getContainer();
	GridData gd = (GridData) container.getLayoutData();
	if (gd.exclude == showUpstreamConfig) {
	gd.exclude = !showUpstreamConfig;
	container.setVisible(showUpstreamConfig);
	container.getParent().layout(true);
	ensurePreferredHeight(getShell());
	}
	}

	private void checkPage() {
	try {
	boolean basedOnLocalBranch = sourceRefName
	.startsWith(Constants.R_HEADS);
	if (basedOnLocalBranch && upstreamConfig != null) {
	setMessage(UIText.CreateBranchPage_LocalBranchWarningMessage,
	IMessageProvider.INFORMATION);
	} else {
	setMessage(UIText.CreateBranchPage_ChooseBranchAndNameMessage);
	}

	if (sourceRefName.length() == 0) {
	setErrorMessage(UIText.CreateBranchPage_MissingSourceMessage);
	return;
	}
	String message = this.myValidator.isValid(nameText.getText());
	if (message != null) {
	setErrorMessage(message);
	return;
	}

	setErrorMessage(null);
	} finally {
	setPageComplete(getErrorMessage() == null
	&& nameText.getText().length() > 0);
	}
	}

	public String getBranchName() {
	return nameText.getText();
	}

	public boolean checkoutNewBranch() {
	return checkout.getSelection();
	}

	/**
	* @param newRefName
	* @param checkoutNewBranch
	* @param monitor
	* @throws CoreException
	* @throws IOException
	*/
	public void createBranch(String newRefName, boolean checkoutNewBranch,
	IProgressMonitor monitor)
	throws CoreException, IOException {
	SubMonitor progress = SubMonitor.convert(monitor,
	checkoutNewBranch ? 2 : 1);
	progress.setTaskName(UIText.CreateBranchPage_CreatingBranchMessage);

	final CreateLocalBranchOperation cbop;

	if (myBaseCommit != null
	&& this.sourceRefName.equals(myBaseCommit.name()))
	cbop = new CreateLocalBranchOperation(myRepository, newRefName,
	myBaseCommit);
	else
	cbop = new CreateLocalBranchOperation(myRepository, newRefName,
	myRepository.findRef(this.sourceRefName),
	upstreamConfig);

	cbop.execute(progress.newChild(1));

	if (checkoutNewBranch && !progress.isCanceled()) {
	progress.setTaskName(UIText.CreateBranchPage_CheckingOutMessage);
	BranchOperationUI.checkout(myRepository, Constants.R_HEADS + newRefName)
	.run(progress.newChild(1));
	}
	}

	private void suggestBranchName(String ref) {
	if (nameText.getText().length() == 0 \|\| nameIsSuggestion) {
	String branchNameSuggestion = getBranchNameSuggestionFromProvider();
	if (branchNameSuggestion == null)
	branchNameSuggestion = getProposedTargetName(ref);

	if (branchNameSuggestion != null) {
	nameText.setText(branchNameSuggestion);
	nameText.selectAll();
	nameIsSuggestion = true;
	}
	}
	}

	private IBranchNameProvider getBranchNameProvider() {
	IExtensionRegistry registry = Platform.getExtensionRegistry();
	IConfigurationElement[] config = registry
	.getConfigurationElementsFor(BRANCH_NAME_PROVIDER_ID);
	if (config.length > 0) {
	Object provider;
	try {
	provider = config[0].createExecutableExtension("class"); //$NON-NLS-1$
	if (provider instanceof IBranchNameProvider)
	return (IBranchNameProvider) provider;
	} catch (Throwable e) {
	Activator.logError(
	UIText.CreateBranchPage_CreateBranchNameProviderFailed,
	e);
	}
	}
	return null;
	}

	private String getBranchNameSuggestionFromProvider() {
	final AtomicReference<String> ref = new AtomicReference<>();
	final IBranchNameProvider branchNameProvider = getBranchNameProvider();
	if (branchNameProvider != null) {
	SafeRunnable.run(() -> ref
	.set(branchNameProvider.getBranchNameSuggestion()));
	}
	return ref.get();
	}

	private static void ensurePreferredHeight(Shell shell) {
	int preferredHeight = shell.computeSize(SWT.DEFAULT, SWT.DEFAULT).y;
	Point size = shell.getSize();
	if (size.y < preferredHeight)
	shell.setSize(size.x, preferredHeight);
	}

	private static class SourceSelectionDialog extends
	AbstractBranchSelectionDialog {

	public SourceSelectionDialog(Shell parentShell, Repository repository,
	String refToMark) {
	super(parentShell, repository, refToMark, SHOW_LOCAL_BRANCHES
	\| SHOW_REMOTE_BRANCHES \| SHOW_TAGS \| SHOW_REFERENCES
	\| SELECT_CURRENT_REF \| EXPAND_LOCAL_BRANCHES_NODE
	\| EXPAND_REMOTE_BRANCHES_NODE);
	}

	@Override
	protected void refNameSelected(String refName) {
	setOkButtonEnabled(refName != null);
	}

	@Override
	protected String getTitle() {
	return UIText.CreateBranchPage_SourceSelectionDialogTitle;
	}

	@Override
	protected String getMessageText() {
	return UIText.CreateBranchPage_SourceSelectionDialogMessage;
	}
	}
	}