Optionally hard-wrap commit message

When "hard-wrap" is enabled in the new Commit Dialog preference page,
the commit message editor automatically inserts newlines as the user is
typing the commit message.

The text width is 70. If a line the user is typing would be longer than
that, a newline is automatically inserted before the last word.
Existing newlines are not touched, to allow for manual formatting (e.g.
ASCII graphics).

The editor shows the commit message in a configurable font that defaults
to the text font. This font is usually fixed-width, so that the margin
line can be shown after exactly 70 characters.

CQ: 4628
Bug: 329489
Change-Id: Ic8ae2f99b595f5f994af3cdb08b9363d2d53e685
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>

11 files changed, 440 insertions, 7 deletions

diff --git a/org.eclipse.egit.ui.test/src/org/eclipse/egit/ui/dialogs/commit/CommitMessageAreaTest.java b/org.eclipse.egit.ui.test/src/org/eclipse/egit/ui/dialogs/commit/CommitMessageAreaTest.java
new file mode 100644
index 0000000000..819b98ddf3
--- /dev/null
+++ b/org.eclipse.egit.ui.test/src/org/eclipse/egit/ui/dialogs/commit/CommitMessageAreaTest.java
@@ -0,0 +1,141 @@
+/*******************************************************************************
+ * Copyright (C) 2010, Robin Stocker
+ *
+ * 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
+ *******************************************************************************/
+package org.eclipse.egit.ui.dialogs.commit;
+
+import static org.junit.Assert.assertEquals;
+
+import java.util.List;
+
+import org.eclipse.egit.ui.internal.dialogs.CommitMessageArea;
+import org.eclipse.egit.ui.internal.dialogs.CommitMessageArea.WrapEdit;
+import org.junit.Test;
+
+public class CommitMessageAreaTest {
+
+	@Test
+	public void dontWrapShortText() {
+		String input = "short message";
+		assertWrappedEquals(input, input);
+	}
+
+	@Test
+	public void dontWrapAlreadyWrappedText() {
+		String input = "This is a test of wrapping\n\nDid it work?\n\nHm?";
+		assertWrappedEquals(input, input);
+	}
+
+	@Test
+	public void dontWrapMaximumLengthText() {
+		String input = "123456789 123456789 123456789 123456789 123456789 123456789 123456789.";
+		assertWrappedEquals(input, input);
+	}
+
+	@Test
+	public void wrapOverlengthText() {
+		String input = "123456789 123456789 123456789 123456789 123456789 123456789 123456789. 123";
+		String expected = "123456789 123456789 123456789 123456789 123456789 123456789 123456789.\n123";
+		assertWrappedEquals(expected, input);
+	}
+
+	@Test
+	public void wrapOverlengthTextByOne() {
+		String input = "123456789 123456789 123456789 123456789 123456789 123456789 123456789ab";
+		String expected = "123456789 123456789 123456789 123456789 123456789 123456789\n123456789ab";
+		assertWrappedEquals(expected, input);
+	}
+
+	@Test
+	public void wrapOverlengthText2() {
+		String input = "123456789 123456789 123456789 123456789 123456789 123456789. 12345678901234";
+		String expected = "123456789 123456789 123456789 123456789 123456789 123456789.\n12345678901234";
+		assertWrappedEquals(expected, input);
+	}
+
+	public void wrapOverlengthTextTwice() {
+		String input = "123456789 123456789 123456789 123456789 123456789 123456789 123456789. "
+				+ "123456789 123456789 123456789 123456789 123456789 123456789 123456789. "
+				+ "123456789 123456789 123456789 123456789 123456789 123456789 123456789.";
+		String expected = "123456789 123456789 123456789 123456789 123456789 123456789 123456789.\n"
+				+ "123456789 123456789 123456789 123456789 123456789 123456789 123456789.\n"
+				+ "123456789 123456789 123456789 123456789 123456789 123456789 123456789.";
+		assertWrappedEquals(expected, input);
+	}
+
+	@Test
+	public void dontWrapWordLongerThanOneLineAtStart() {
+		String input = "12345678901234567890123456789012345678901234567890123456789012345678901234567890 the previous was longer than a line";
+		String expected = "12345678901234567890123456789012345678901234567890123456789012345678901234567890\nthe previous was longer than a line";
+		assertWrappedEquals(expected, input);
+	}
+
+	@Test
+	public void dontWrapWordLongerThanOneLine() {
+		String input = "This has to be on its own line: 12345678901234567890123456789012345678901234567890123456789012345678901234567890 this not";
+		String expected = "This has to be on its own line:\n12345678901234567890123456789012345678901234567890123456789012345678901234567890\nthis not";
+		assertWrappedEquals(expected, input);
+	}
+
+	@Test
+	public void wrapSecondLongLine() {
+		String input = "First line\n123456789 123456789 123456789 123456789 123456789 123456789 123456789 123456789.";
+		String expected = "First line\n123456789 123456789 123456789 123456789 123456789 123456789 123456789\n123456789.";
+		assertWrappedEquals(expected, input);
+	}
+
+	@Test
+	public void keepExistingNewlines() {
+		String input = "This\n\nis\nall\nok\n123456789 123456789 123456789 123456789 123456789 123456789 123456789.";
+		assertWrappedEquals(input, input);
+	}
+
+	@Test
+	public void keepNewlineAtEnd() {
+		String input = "Newline\nat\nend\n";
+		assertWrappedEquals(input, input);
+	}
+
+	@Test
+	public void keepWhitespace() {
+		String input = "  this   is     deliberate whitespace";
+		assertWrappedEquals(input, input);
+	}
+
+	@Test
+	public void keepTrailingSpace() {
+		String input = "space at end ";
+		assertWrappedEquals(input, input);
+	}
+
+	private static void assertWrappedEquals(String expected, String input) {
+		assertWrappedEqualsOnUnix(expected, input);
+		assertWrappedEqualsOnWindows(expected, input);
+	}
+
+	private static void assertWrappedEqualsOnUnix(String expected, String input) {
+		String wrapped = wrap(input, "\n");
+		assertEquals(expected, wrapped);
+	}
+
+	private static void assertWrappedEqualsOnWindows(String expected,
+			String input) {
+		String wrapped = wrap(input.replaceAll("\n", "\r\n"), "\r\n");
+		assertEquals(expected.replaceAll("\n", "\r\n"), wrapped);
+	}
+
+	private static String wrap(String text, String lineDelimiter) {
+		StringBuilder sb = new StringBuilder(text);
+		List<WrapEdit> wrapEdits = CommitMessageArea.calculateWrapEdits(text, 70,
+				lineDelimiter);
+		for (WrapEdit wrapEdit : wrapEdits) {
+			sb.replace(wrapEdit.getStart(),
+					wrapEdit.getStart() + wrapEdit.getLength(), lineDelimiter);
+		}
+		return sb.toString();
+	}
+}
diff --git a/org.eclipse.egit.ui.test/src/org/eclipse/egit/ui/test/AllLocalTests.java b/org.eclipse.egit.ui.test/src/org/eclipse/egit/ui/test/AllLocalTests.java
index ef5c6c53f1..65486e3320 100644
--- a/org.eclipse.egit.ui.test/src/org/eclipse/egit/ui/test/AllLocalTests.java
+++ b/org.eclipse.egit.ui.test/src/org/eclipse/egit/ui/test/AllLocalTests.java
@@ -8,6 +8,7 @@
  *******************************************************************************/
 package org.eclipse.egit.ui.test;
 
+import org.eclipse.egit.ui.dialogs.commit.CommitMessageAreaTest;
 import org.eclipse.egit.ui.prefpages.configuration.GlobalConfigurationPageTest;
 import org.eclipse.egit.ui.test.history.HistoryViewTest;
 import org.eclipse.egit.ui.test.team.actions.AllTeamActionTests;
@@ -27,6 +28,7 @@ import org.junit.runners.Suite.SuiteClasses;
 		SharingWizardTest.class,					//
 		AllTeamActionTests.class,                   //
 		HistoryViewTest.class,                      //
+		CommitMessageAreaTest.class,
 		TraceConfigurationDialogTest.class,
 		SynchronizeViewTest.class})
 public class AllLocalTests {
diff --git a/org.eclipse.egit.ui/plugin.properties b/org.eclipse.egit.ui/plugin.properties
index 69b75b29ca..d6b3bfc1cb 100644
--- a/org.eclipse.egit.ui/plugin.properties
+++ b/org.eclipse.egit.ui/plugin.properties
@@ -55,6 +55,8 @@ Theme_CommitGraphHighlightFont_label=Commit graph highlight font
 Theme_CommitGraphHighlightFont_description=This font is used to highlight matching commits in the revision history.
 Theme_CommitMessageFont_label=Commit message font
 Theme_CommitMessageFont_description=This font is used to show a commit message.
+Theme_CommitMessageEditorFont_label=Commit message editor font
+Theme_CommitMessageEditorFont_description=This font is used when entering a commit message.
 Theme_UncommittedChangeForegroundColor_label=Uncommitted Change (Foreground)
 Theme_UncommittedChangeForegroundColor_description=This color is used for the foreground color for resources that have outgoing changes.
 Theme_UncommittedChangeBackgroundColor_label=Uncommitted Change (Background)
@@ -65,6 +67,7 @@ Theme_UncommittedChangeFont_description=The font used to display outgoing change
 GitPreferences_name=Git
 GitPreferences_WindowCachePreferencePage_name=Window Cache
 GitPreferences_DecoratorPreferencePage_name=Label Decorations
+GitPreferences_CommitDialogPreferencePage_name=Commit Dialog
 
 ShareProjectCommand_name=Share with Git
 ShareProjectCommand_desc=Share the project using Git
diff --git a/org.eclipse.egit.ui/plugin.xml b/org.eclipse.egit.ui/plugin.xml
index ffc2c12f2e..ee2c43c900 100644
--- a/org.eclipse.egit.ui/plugin.xml
+++ b/org.eclipse.egit.ui/plugin.xml
@@ -328,7 +328,7 @@
 		  id="org.eclipse.egit.ui.keyword.git">
 	    </keywordReference>
       </page>
-   <page
+      <page
          category="org.eclipse.egit.ui.GitPreferences"
          class="org.eclipse.egit.ui.internal.preferences.GlobalConfigurationPreferencePage"
          id="org.eclipse.egit.ui.internal.preferences.GlobalConfigurationPreferencePage"
@@ -336,7 +336,16 @@
       <keywordReference
             id="org.eclipse.egit.ui.keyword.git">
       </keywordReference>
-   </page>
+      </page>
+      <page
+            category="org.eclipse.egit.ui.GitPreferences"
+            class="org.eclipse.egit.ui.internal.preferences.CommitDialogPreferencePage"
+            id="org.eclipse.egit.ui.internal.preferences.CommitDialogPreferencePage"
+            name="%GitPreferences_CommitDialogPreferencePage_name">
+         <keywordReference
+               id="org.eclipse.egit.ui.keyword.git">
+         </keywordReference>
+      </page>
    </extension>
 
    <extension point="org.eclipse.ui.propertyPages">
@@ -441,6 +450,15 @@
         %Theme_UncommittedChangeFont_description
         </description>
       </fontDefinition>
+      <fontDefinition
+            categoryId="org.eclipse.egit.ui.GitTheme"
+            defaultsTo="org.eclipse.jface.textfont"
+            id="org.eclipse.egit.ui.CommitMessageEditorFont"
+            label="%Theme_CommitMessageEditorFont_label">
+         <description>
+            %Theme_CommitMessageEditorFont_description
+         </description>
+      </fontDefinition>
    </extension>
 
 <!-- ********** QuickDiff text editor support ************** -->
diff --git a/org.eclipse.egit.ui/src/org/eclipse/egit/ui/PluginPreferenceInitializer.java b/org.eclipse.egit.ui/src/org/eclipse/egit/ui/PluginPreferenceInitializer.java
index 2908bfc6bb..4d0c355064 100644
--- a/org.eclipse.egit.ui/src/org/eclipse/egit/ui/PluginPreferenceInitializer.java
+++ b/org.eclipse.egit.ui/src/org/eclipse/egit/ui/PluginPreferenceInitializer.java
@@ -64,6 +64,7 @@ public class PluginPreferenceInitializer extends AbstractPreferenceInitializer {
 
 		store.setDefault(UIPreferences.FINDTOOLBAR_IGNORE_CASE, true);
 		store.setDefault(UIPreferences.FINDTOOLBAR_FIND_IN, 2);
+		store.setDefault(UIPreferences.COMMIT_DIALOG_HARD_WRAP_MESSAGE, true);
 
 		store.setDefault(UIPreferences.REFESH_ON_INDEX_CHANGE, true);
 		store.setDefault(UIPreferences.REFESH_ONLY_WHEN_ACTIVE, true);
diff --git a/org.eclipse.egit.ui/src/org/eclipse/egit/ui/UIPreferences.java b/org.eclipse.egit.ui/src/org/eclipse/egit/ui/UIPreferences.java
index 0d3c7f163f..57a20ea778 100644
--- a/org.eclipse.egit.ui/src/org/eclipse/egit/ui/UIPreferences.java
+++ b/org.eclipse.egit.ui/src/org/eclipse/egit/ui/UIPreferences.java
@@ -50,6 +50,8 @@ public class UIPreferences {
 	public final static String FINDTOOLBAR_COMMITTER = "findtoolbar_committer"; //$NON-NLS-1$
 	/** */
 	public final static String FINDTOOLBAR_FIND_IN = "findtoolbar_find_in"; //$NON-NLS-1$
+	/** */
+	public final static String COMMIT_DIALOG_HARD_WRAP_MESSAGE = "commit_dialog_hard_wrap_message"; //$NON-NLS-1$
 
 	/** */
 	public final static String THEME_CommitGraphNormalFont = "org.eclipse.egit.ui.CommitGraphNormalFont"; //$NON-NLS-1$
@@ -58,6 +60,8 @@ public class UIPreferences {
 	/** */
 	public final static String THEME_CommitMessageFont = "org.eclipse.egit.ui.CommitMessageFont"; //$NON-NLS-1$
 	/** */
+	public final static String THEME_CommitMessageEditorFont = "org.eclipse.egit.ui.CommitMessageEditorFont"; //$NON-NLS-1$
+	/** */
 	public final static String THEME_UncommittedChangeForegroundColor = "org.eclipse.egit.ui.UncommittedChangeForegroundColor"; //$NON-NLS-1$
 	/** */
 	public final static String THEME_UncommittedChangeBackgroundColor = "org.eclipse.egit.ui.UncommittedChangeBackgroundColor"; //$NON-NLS-1$
diff --git a/org.eclipse.egit.ui/src/org/eclipse/egit/ui/UIText.java b/org.eclipse.egit.ui/src/org/eclipse/egit/ui/UIText.java
index 118463be38..e3cf4cd7be 100644
--- a/org.eclipse.egit.ui/src/org/eclipse/egit/ui/UIText.java
+++ b/org.eclipse.egit.ui/src/org/eclipse/egit/ui/UIText.java
@@ -1303,6 +1303,9 @@ public class UIText extends NLS {
 	public static String CommitDialog_AddChangeIdTooltip;
 
 	/** */
+	public static String CommitDialog_ConfigureLink;
+
+	/** */
 	public static String ConfigurationEditorComponent_AddButton;
 
 	/** */
@@ -1792,6 +1795,15 @@ public class UIText extends NLS {
 	public static String BranchSelectionDialog_Rename;
 
 	/** */
+	public static String CommitDialogPreferencePage_title;
+
+	/** */
+	public static String CommitDialogPreferencePage_hardWrapMessage;
+
+	/** */
+	public static String CommitDialogPreferencePage_hardWrapMessageTooltip;
+
+	/** */
 	public static String Decorator_exceptionMessage;
 
 	/** */
diff --git a/org.eclipse.egit.ui/src/org/eclipse/egit/ui/internal/dialogs/CommitDialog.java b/org.eclipse.egit.ui/src/org/eclipse/egit/ui/internal/dialogs/CommitDialog.java
index 91352f3387..f14a4a2b0b 100644
--- a/org.eclipse.egit.ui/src/org/eclipse/egit/ui/internal/dialogs/CommitDialog.java
+++ b/org.eclipse.egit.ui/src/org/eclipse/egit/ui/internal/dialogs/CommitDialog.java
@@ -47,6 +47,7 @@ import org.eclipse.jface.dialogs.IDialogConstants;
 import org.eclipse.jface.dialogs.IDialogSettings;
 import org.eclipse.jface.dialogs.MessageDialog;
 import org.eclipse.jface.layout.GridDataFactory;
+import org.eclipse.jface.preference.PreferenceDialog;
 import org.eclipse.jface.viewers.ArrayContentProvider;
 import org.eclipse.jface.viewers.CheckStateChangedEvent;
 import org.eclipse.jface.viewers.CheckboxTableViewer;
@@ -72,12 +73,14 @@ import org.eclipse.swt.events.SelectionAdapter;
 import org.eclipse.swt.events.SelectionEvent;
 import org.eclipse.swt.events.SelectionListener;
 import org.eclipse.swt.graphics.Image;
+import org.eclipse.swt.graphics.Point;
 import org.eclipse.swt.layout.GridLayout;
 import org.eclipse.swt.widgets.Button;
 import org.eclipse.swt.widgets.Composite;
 import org.eclipse.swt.widgets.Control;
 import org.eclipse.swt.widgets.Event;
 import org.eclipse.swt.widgets.Label;
+import org.eclipse.swt.widgets.Link;
 import org.eclipse.swt.widgets.Listener;
 import org.eclipse.swt.widgets.Menu;
 import org.eclipse.swt.widgets.MenuItem;
@@ -89,6 +92,7 @@ import org.eclipse.team.core.RepositoryProvider;
 import org.eclipse.team.core.history.IFileHistory;
 import org.eclipse.team.core.history.IFileHistoryProvider;
 import org.eclipse.team.core.history.IFileRevision;
+import org.eclipse.ui.dialogs.PreferencesUtil;
 import org.eclipse.ui.model.WorkbenchLabelProvider;
 
 /**
@@ -194,8 +198,10 @@ public class CommitDialog extends Dialog {
 		label.setLayoutData(GridDataFactory.fillDefaults().span(2, 1).grab(true, false).create());
 
 		commitText = new CommitMessageArea(container, commitMessage);
+		Point size = commitText.getTextWidget().getSize();
+		int minHeight = commitText.getTextWidget().getLineHeight() * 3;
 		commitText.setLayoutData(GridDataFactory.fillDefaults().span(2, 1).grab(true, true)
-				.hint(600, 200).create());
+				.hint(size).minSize(size.x, minHeight).align(SWT.FILL, SWT.FILL).create());
 		commitText.setText(commitMessage);
 
 		// allow to commit with ctrl-enter
@@ -241,6 +247,20 @@ public class CommitDialog extends Dialog {
 
 		committerHandler = UIUtils.addPreviousValuesContentProposalToText(committerText, COMMITTER_VALUES_PREF);
 
+		Link preferencesLink = new Link(container, SWT.NONE);
+		preferencesLink.setText(UIText.CommitDialog_ConfigureLink);
+		preferencesLink.addSelectionListener(new SelectionAdapter() {
+			@Override
+			public void widgetSelected(SelectionEvent e) {
+				String preferencePageId = "org.eclipse.egit.ui.internal.preferences.CommitDialogPreferencePage"; //$NON-NLS-1$
+				PreferenceDialog dialog = PreferencesUtil
+						.createPreferenceDialogOn(null, preferencePageId,
+								new String[] { preferencePageId }, null);
+				dialog.open();
+				commitText.reconfigure();
+			}
+		});
+
 		amendingButton = new Button(container, SWT.CHECK);
 		if (amending) {
 			amendingButton.setSelection(amending);
@@ -599,7 +619,7 @@ public class CommitDialog extends Dialog {
 	 * @return The message the user entered
 	 */
 	public String getCommitMessage() {
-		return commitMessage.replaceAll(Text.DELIMITER, "\n"); //$NON-NLS-1$;
+		return commitMessage;
 	}
 
 	/**
@@ -740,7 +760,7 @@ public class CommitDialog extends Dialog {
 
 	@Override
 	protected void okPressed() {
-		commitMessage = commitText.getText();
+		commitMessage = commitText.getCommitMessage();
 		author = authorText.getText().trim();
 		committer = committerText.getText().trim();
 		signedOff = signedOffButton.getSelection();
diff --git a/org.eclipse.egit.ui/src/org/eclipse/egit/ui/internal/dialogs/CommitMessageArea.java b/org.eclipse.egit.ui/src/org/eclipse/egit/ui/internal/dialogs/CommitMessageArea.java
index aebcfcdd97..adb9594d34 100644
--- a/org.eclipse.egit.ui/src/org/eclipse/egit/ui/internal/dialogs/CommitMessageArea.java
+++ b/org.eclipse.egit.ui/src/org/eclipse/egit/ui/internal/dialogs/CommitMessageArea.java
@@ -12,9 +12,13 @@
 package org.eclipse.egit.ui.internal.dialogs;
 
 import java.util.Iterator;
+import java.util.LinkedList;
 import java.util.List;
 
+import org.eclipse.egit.ui.Activator;
+import org.eclipse.egit.ui.UIPreferences;
 import org.eclipse.egit.ui.UIText;
+import org.eclipse.egit.ui.UIUtils;
 import org.eclipse.jface.action.Action;
 import org.eclipse.jface.action.IAction;
 import org.eclipse.jface.action.IMenuListener;
@@ -47,7 +51,11 @@ import org.eclipse.swt.events.DisposeEvent;
 import org.eclipse.swt.events.DisposeListener;
 import org.eclipse.swt.events.FocusEvent;
 import org.eclipse.swt.events.FocusListener;
+import org.eclipse.swt.events.ModifyEvent;
+import org.eclipse.swt.events.ModifyListener;
+import org.eclipse.swt.graphics.GC;
 import org.eclipse.swt.graphics.Image;
+import org.eclipse.swt.graphics.Point;
 import org.eclipse.swt.layout.FillLayout;
 import org.eclipse.swt.widgets.Composite;
 import org.eclipse.swt.widgets.Display;
@@ -118,6 +126,7 @@ public class CommitMessageArea extends Composite {
 	}
 
 	private final SourceViewer sourceViewer;
+	private ModifyListener hardWrapModifyListener;
 
 	/**
 	 * @param parent
@@ -130,10 +139,19 @@ public class CommitMessageArea extends Composite {
 		AnnotationModel annotationModel = new AnnotationModel();
 		sourceViewer = new SourceViewer(this, null, null, true, SWT.MULTI
 				| SWT.V_SCROLL | SWT.WRAP);
-		getTextWidget().setIndent(2);
+		getTextWidget().setFont(UIUtils
+				.getFont(UIPreferences.THEME_CommitMessageEditorFont));
+
+		int endSpacing = 2;
+		int textWidth = getCharWidth() * 70 + endSpacing;
+		int textHeight = getLineHeight() * 7;
+		Point size = getTextWidget().computeSize(textWidth, textHeight);
+		getTextWidget().setSize(size);
 
 		createMarginPainter();
 
+		configureHardWrap();
+
 		final SourceViewerDecorationSupport support = configureAnnotationPreferences();
 		final IHandlerActivation handlerActivation = installQuickFixActionHandler();
 
@@ -153,6 +171,39 @@ public class CommitMessageArea extends Composite {
 		});
 	}
 
+	private void configureHardWrap() {
+		if (shouldHardWrap()) {
+			if (hardWrapModifyListener == null) {
+				final StyledText textWidget = getTextWidget();
+
+				hardWrapModifyListener = new ModifyListener() {
+
+					private boolean active = true;
+
+					public void modifyText(ModifyEvent e) {
+						if (!active) {
+							return;
+						}
+						String lineDelimiter = textWidget.getLineDelimiter();
+						List<WrapEdit> wrapEdits = calculateWrapEdits(textWidget.getText(), 70, lineDelimiter);
+						// Prevent infinite loop because replaceTextRange causes a ModifyEvent
+						active = false;
+						for (WrapEdit wrapEdit : wrapEdits) {
+							textWidget.replaceTextRange(wrapEdit.getStart(), wrapEdit.getLength(), lineDelimiter);
+						}
+						active = true;
+					}
+				};
+				textWidget.addModifyListener(hardWrapModifyListener);
+			}
+		} else {
+			if (hardWrapModifyListener != null) {
+				getTextWidget().removeModifyListener(hardWrapModifyListener);
+				hardWrapModifyListener = null;
+			}
+		}
+	}
+
 	private void configureContextMenu() {
 		final TextViewerAction cutAction = new TextViewerAction(sourceViewer, ITextOperationTarget.CUT);
 		cutAction.setText(UIText.CommitMessageArea_cut);
@@ -311,12 +362,31 @@ public class CommitMessageArea extends Composite {
 
 	private void createMarginPainter() {
 		MarginPainter marginPainter = new MarginPainter(sourceViewer);
-		marginPainter.setMarginRulerColumn(65);
+		marginPainter.setMarginRulerColumn(70);
 		marginPainter.setMarginRulerColor(Display.getDefault().getSystemColor(
 				SWT.COLOR_GRAY));
 		sourceViewer.addPainter(marginPainter);
 	}
 
+	private int getCharWidth() {
+		GC gc = new GC(getTextWidget());
+		int charWidth = gc.getFontMetrics().getAverageCharWidth();
+		gc.dispose();
+		return charWidth;
+	}
+
+	private int getLineHeight() {
+		return getTextWidget().getLineHeight();
+	}
+
+	/**
+	 * @return if the commit message should be hard-wrapped (preference)
+	 */
+	private static boolean shouldHardWrap() {
+		return Activator.getDefault().getPreferenceStore()
+				.getBoolean(UIPreferences.COMMIT_DIALOG_HARD_WRAP_MESSAGE);
+	}
+
 	/**
 	 * @return widget
 	 */
@@ -352,6 +422,24 @@ public class CommitMessageArea extends Composite {
 	}
 
 	/**
+	 * Return the commit message, converting platform-specific line endings.
+	 *
+	 * @return commit message
+	 */
+	public String getCommitMessage() {
+		String text = getText();
+		text = text.replaceAll(getTextWidget().getLineDelimiter(), "\n"); //$NON-NLS-1$
+		return text;
+	}
+
+	/**
+	 * Reconfigure this widget if a preference has changed.
+	 */
+	public void reconfigure() {
+		configureHardWrap();
+	}
+
+	/**
 	 * @return text
 	 */
 	public String getText() {
@@ -372,4 +460,95 @@ public class CommitMessageArea extends Composite {
 		return getTextWidget().setFocus();
 	}
 
+	/**
+	 * Calculate a list of {@link WrapEdit} which can be applied to the text to
+	 * get a new text that is wrapped at word boundaries. Existing line breaks
+	 * are left alone (text is not reflowed).
+	 *
+	 * @param text
+	 *            the text to calculate the wrap edits for
+	 * @param maxLineLength
+	 *            the maximum line length
+	 * @param lineDelimiter
+	 *            line delimiter used in text and for wrapping
+	 * @return a list of {@link WrapEdit} objects which specify how the text
+	 *         should be edited to obtain the wrapped text. Offsets of later
+	 *         edits are already adjusted for the fact that wrapping a line may
+	 *         shift the text backwards. So the list can just be iterated and
+	 *         each edit applied in order.
+	 */
+	public static List<WrapEdit> calculateWrapEdits(final String text, final int maxLineLength, final String lineDelimiter) {
+		List<WrapEdit> wrapEdits = new LinkedList<WrapEdit>();
+
+		int offset = 0;
+		int lineDelimiterLength = lineDelimiter.length();
+
+		String[] chunks = text.split(lineDelimiter, -1);
+		for (int chunkIndex = 0; chunkIndex < chunks.length; chunkIndex++) {
+			String chunk = chunks[chunkIndex];
+
+			String[] words = chunk.split(" ", -1); //$NON-NLS-1$
+			int lineLength = 0;
+
+			for (int wordIndex = 0; wordIndex < words.length; wordIndex++) {
+				String word = words[wordIndex];
+
+				int wordLength = word.length();
+				int newLineLength = lineLength + wordLength + 1 /* the space */;
+				if (newLineLength > maxLineLength) {
+					/* don't break before a single long word */
+					if (lineLength != 0) {
+						wrapEdits.add(new WrapEdit(offset, 1));
+						/* adjust for the shifting of text after the edit is applied */
+						offset += lineDelimiterLength;
+					}
+					lineLength = 0;
+				} else if (wordIndex != 0) {
+					lineLength += 1;
+					offset += 1;
+				}
+				offset += wordLength;
+				lineLength += wordLength;
+			}
+
+			if (chunkIndex != chunks.length - 1) {
+				offset += lineDelimiterLength;
+			}
+		}
+
+		return wrapEdits;
+	}
+
+	/**
+	 * Edit for replacing a space with a line delimiter to wrap a long line.
+	 */
+	public static class WrapEdit {
+		private int start;
+		private int length;
+
+		/**
+		 * @param start see {@link #getStart()}
+		 * @param length see {@link #getLength()}
+		 */
+		public WrapEdit(int start, int length) {
+			this.start = start;
+			this.length = length;
+		}
+
+		/**
+		 * @return character offset of where the edit should be applied on the
+		 *         text
+		 */
+		public int getStart() {
+			return start;
+		}
+
+		/**
+		 * @return number of characters which should be replaced by the line
+		 *         delimiter
+		 */
+		public int getLength() {
+			return length;
+		}
+	}
 }
diff --git a/org.eclipse.egit.ui/src/org/eclipse/egit/ui/internal/preferences/CommitDialogPreferencePage.java b/org.eclipse.egit.ui/src/org/eclipse/egit/ui/internal/preferences/CommitDialogPreferencePage.java
new file mode 100644
index 0000000000..8c85546575
--- /dev/null
+++ b/org.eclipse.egit.ui/src/org/eclipse/egit/ui/internal/preferences/CommitDialogPreferencePage.java
@@ -0,0 +1,48 @@
+/*******************************************************************************
+ * Copyright (C) 2010, Robin Stocker <robin@nibor.org>
+ *
+ * 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
+ *******************************************************************************/
+package org.eclipse.egit.ui.internal.preferences;
+
+import org.eclipse.egit.ui.Activator;
+import org.eclipse.egit.ui.UIPreferences;
+import org.eclipse.egit.ui.UIText;
+import org.eclipse.jface.preference.BooleanFieldEditor;
+import org.eclipse.jface.preference.FieldEditorPreferencePage;
+import org.eclipse.jface.preference.IPreferenceStore;
+import org.eclipse.ui.IWorkbench;
+import org.eclipse.ui.IWorkbenchPreferencePage;
+
+/** Preferences for commit dialog. */
+public class CommitDialogPreferencePage extends FieldEditorPreferencePage
+		implements IWorkbenchPreferencePage {
+
+	/** */
+	public CommitDialogPreferencePage() {
+		super(GRID);
+		setTitle(UIText.CommitDialogPreferencePage_title);
+	}
+
+	public void init(IWorkbench workbench) {
+		// Nothing to do
+	}
+
+	@Override
+	protected IPreferenceStore doGetPreferenceStore() {
+		return Activator.getDefault().getPreferenceStore();
+	}
+
+	@Override
+	protected void createFieldEditors() {
+		BooleanFieldEditor hardWrap = new BooleanFieldEditor(
+				UIPreferences.COMMIT_DIALOG_HARD_WRAP_MESSAGE,
+				UIText.CommitDialogPreferencePage_hardWrapMessage,
+				getFieldEditorParent());
+		hardWrap.getDescriptionControl(getFieldEditorParent()).setToolTipText(UIText.CommitDialogPreferencePage_hardWrapMessageTooltip);
+		addField(hardWrap);
+	}
+}
diff --git a/org.eclipse.egit.ui/src/org/eclipse/egit/ui/uitext.properties b/org.eclipse.egit.ui/src/org/eclipse/egit/ui/uitext.properties
index 8cecdb5c4c..8ad3a635a6 100644
--- a/org.eclipse.egit.ui/src/org/eclipse/egit/ui/uitext.properties
+++ b/org.eclipse.egit.ui/src/org/eclipse/egit/ui/uitext.properties
@@ -455,6 +455,7 @@ CommitDialog_StatusUnknown=Unknown
 CommitDialog_StatusUntracked=Untracked
 CommitDialog_AddChangeIdLabel=Compute Change-Id for Gerrit Code Review
 CommitDialog_AddChangeIdTooltip=Inserts the final id when you press Commit
+CommitDialog_ConfigureLink=<a>Configure Preferences...</a>
 
 ConfigureRemoteWizard_WizardTitle_Change=Change remote configuration {0}
 ConfigureRemoteWizard_WizardTitle_New=Create a new remote configuration
@@ -598,6 +599,10 @@ RefreshPreferencePage_title=Git Detected Workspace Refresh
 RefreshPreferencesPage_RefreshOnlyWhenActive=Refresh only when workbench is &active
 RefreshPreferencesPage_RefreshWhenIndexChange=Refresh resources when &index changes
 
+CommitDialogPreferencePage_title=Commit Dialog
+CommitDialogPreferencePage_hardWrapMessage=Hard-wrap commit message
+CommitDialogPreferencePage_hardWrapMessageTooltip=Wrap text in commit message editor while typing
+
 BranchAction_branchFailed=Branch failed
 BranchAction_cannotCheckout=Cannot checkout now
 BranchAction_checkingOut=Checking out {0}