Add compare with previous revision menu.

This opens the compare editor for single file
selections and the Git Tree compare view for
non-file selections.

Bug: 344026
Change-Id: Ibb1cadfdc56376a5cf0110b8cc0105d8067cd20d
Signed-off-by: Kevin Sawicki <kevin@github.com>

7 files changed, 223 insertions, 1 deletions

diff --git a/org.eclipse.egit.ui/plugin.properties b/org.eclipse.egit.ui/plugin.properties
index 936bbf579c..77fd6dad5e 100644
--- a/org.eclipse.egit.ui/plugin.properties
+++ b/org.eclipse.egit.ui/plugin.properties
@@ -263,4 +263,6 @@ RenameBranchMenu.label = Rename Branch...
 DeleteBranchMenu.label = Delete Branch...
 DeleteBranchCommand.name = Delete Branch
 RenameBranchCommand.name = Rename Branch
-CompareInTreeCommand.name = Compare in Tree
\ No newline at end of file
+CompareInTreeCommand.name = Compare in Tree
+CompareWithPreviousCommand.name = Compare with Previous Revision
+CompareWithPreviousAction.label = Previous Revision
\ No newline at end of file
diff --git a/org.eclipse.egit.ui/plugin.xml b/org.eclipse.egit.ui/plugin.xml
index 07fcff3d3b..01551fe030 100644
--- a/org.eclipse.egit.ui/plugin.xml
+++ b/org.eclipse.egit.ui/plugin.xml
@@ -116,6 +116,13 @@
                label="%CompareWithBranchOrTagAction.label"
                menubarPath="compareWithMenu/gitCompareWithGroup">
          </action>
+          <action
+               class="org.eclipse.egit.ui.internal.actions.CompareWithPreviousAction"
+               definitionId="org.eclipse.egit.ui.team.CompareWithPrevious"
+               enablesFor="1"
+               id="org.eclipse.egit.ui.internal.actions.CompareWithPreviousAction"
+               label="%CompareWithPreviousAction.label"
+               menubarPath="compareWithMenu/gitCompareWithGroup"/>
          <action
                class="org.eclipse.egit.ui.internal.actions.CompareWithHeadAction"
                id="org.eclipse.egit.ui.internal.actions.CompareWithHeadAction"
@@ -3130,6 +3137,12 @@
             id="org.eclipse.egit.ui.team.CompareWithHead"
             name="%CompareWithHeadCommand.name">
       </command>
+      <command
+            categoryId="org.eclipse.egit.ui.commandCategory"
+            defaultHandler="org.eclipse.egit.ui.internal.actions.CompareWithPreviousActionHandler"
+            id="org.eclipse.egit.ui.team.CompareWithPrevious"
+            name="%CompareWithPreviousCommand.name">
+      </command>
             <command
             categoryId="org.eclipse.egit.ui.commandCategory"
             id="org.eclipse.egit.ui.team.CompareWithRevision"
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 03cd122df1..17673ee784 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
@@ -1741,6 +1741,15 @@ public class UIText extends NLS {
 	public static String CompareWithIndexAction_errorOnAddToIndex;
 
 	/** */
+	public static String CompareWithPreviousActionHandler_MessageRevisionNotFound;
+
+	/** */
+	public static String CompareWithPreviousActionHandler_TaskGeneratingInput;
+
+	/** */
+	public static String CompareWithPreviousActionHandler_TitleRevisionNotFound;
+
+	/** */
 	public static String ConfirmationPage_cantConnectToAnyTitle;
 
 	/** */
diff --git a/org.eclipse.egit.ui/src/org/eclipse/egit/ui/internal/actions/ActionCommands.java b/org.eclipse.egit.ui/src/org/eclipse/egit/ui/internal/actions/ActionCommands.java
index e883a9cb7a..6d4b5b595a 100644
--- a/org.eclipse.egit.ui/src/org/eclipse/egit/ui/internal/actions/ActionCommands.java
+++ b/org.eclipse.egit.ui/src/org/eclipse/egit/ui/internal/actions/ActionCommands.java
@@ -41,6 +41,9 @@ public class ActionCommands {
 	/** "Compare with revision" action command id */
 	public static final String COMPARE_WITH_REVISION_ACTION = "org.eclipse.egit.ui.team.CompareWithRevision"; //$NON-NLS-1$
 
+	/** "Compare with previous" action command id */
+	public static final String COMPARE_WITH_PREVIOUS_ACTION = "org.eclipse.egit.ui.team.CompareWithPrevious"; //$NON-NLS-1$
+
 	/** "Configure Fetch" action command id */
 	public static final String CONFIGURE_FETCH = "org.eclipse.egit.ui.team.ConfigureFetch"; //$NON-NLS-1$
 
diff --git a/org.eclipse.egit.ui/src/org/eclipse/egit/ui/internal/actions/CompareWithPreviousAction.java b/org.eclipse.egit.ui/src/org/eclipse/egit/ui/internal/actions/CompareWithPreviousAction.java
new file mode 100644
index 0000000000..7128f8a089
--- /dev/null
+++ b/org.eclipse.egit.ui/src/org/eclipse/egit/ui/internal/actions/CompareWithPreviousAction.java
@@ -0,0 +1,26 @@
+/*******************************************************************************
+ *  Copyright (c) 2011 GitHub Inc.
+ *  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
+ *
+ *  Contributors:
+ *    Kevin Sawicki (GitHub Inc.) - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.egit.ui.internal.actions;
+
+/**
+ * Compare with previous revision action.
+ */
+public class CompareWithPreviousAction extends RepositoryAction {
+
+	/**
+	 * Create compare with previous revision action
+	 */
+	public CompareWithPreviousAction() {
+		super(ActionCommands.COMPARE_WITH_PREVIOUS_ACTION,
+				new CompareWithPreviousActionHandler());
+	}
+
+}
diff --git a/org.eclipse.egit.ui/src/org/eclipse/egit/ui/internal/actions/CompareWithPreviousActionHandler.java b/org.eclipse.egit.ui/src/org/eclipse/egit/ui/internal/actions/CompareWithPreviousActionHandler.java
new file mode 100644
index 0000000000..45267d1223
--- /dev/null
+++ b/org.eclipse.egit.ui/src/org/eclipse/egit/ui/internal/actions/CompareWithPreviousActionHandler.java
@@ -0,0 +1,166 @@
+/*******************************************************************************
+ *  Copyright (c) 2011 GitHub Inc.
+ *  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
+ *
+ *  Contributors:
+ *    Kevin Sawicki (GitHub Inc.) - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.egit.ui.internal.actions;
+
+import java.io.IOException;
+import java.text.MessageFormat;
+
+import org.eclipse.compare.CompareEditorInput;
+import org.eclipse.compare.CompareUI;
+import org.eclipse.compare.ITypedElement;
+import org.eclipse.core.commands.ExecutionEvent;
+import org.eclipse.core.commands.ExecutionException;
+import org.eclipse.core.resources.IFile;
+import org.eclipse.core.resources.IResource;
+import org.eclipse.core.runtime.CoreException;
+import org.eclipse.core.runtime.IProgressMonitor;
+import org.eclipse.core.runtime.jobs.ISchedulingRule;
+import org.eclipse.egit.core.op.IEGitOperation;
+import org.eclipse.egit.core.project.RepositoryMapping;
+import org.eclipse.egit.ui.Activator;
+import org.eclipse.egit.ui.UIText;
+import org.eclipse.egit.ui.internal.CompareUtils;
+import org.eclipse.egit.ui.internal.GitCompareFileRevisionEditorInput;
+import org.eclipse.egit.ui.internal.dialogs.CompareTreeView;
+import org.eclipse.egit.ui.internal.job.JobUtil;
+import org.eclipse.jface.dialogs.MessageDialog;
+import org.eclipse.jgit.lib.Constants;
+import org.eclipse.jgit.lib.Repository;
+import org.eclipse.jgit.revwalk.FollowFilter;
+import org.eclipse.jgit.revwalk.RevCommit;
+import org.eclipse.jgit.revwalk.RevWalk;
+import org.eclipse.swt.widgets.Shell;
+import org.eclipse.team.ui.synchronize.SaveableCompareEditorInput;
+import org.eclipse.ui.PartInitException;
+import org.eclipse.ui.PlatformUI;
+import org.eclipse.ui.handlers.HandlerUtil;
+
+/**
+ * Compare with previous revision action handler.
+ */
+public class CompareWithPreviousActionHandler extends RepositoryActionHandler {
+
+	private class CompareWithPreviousOperation implements IEGitOperation {
+
+		private ExecutionEvent event;
+
+		private Repository repository;
+
+		private IResource resource;
+
+		private CompareWithPreviousOperation(ExecutionEvent event,
+				Repository repository, IResource resource) {
+			this.event = event;
+			this.repository = repository;
+			this.resource = resource;
+		}
+
+		private String getRepositoryPath() {
+			return RepositoryMapping.getMapping(resource.getProject())
+					.getRepoRelativePath(resource);
+		}
+
+		public void execute(IProgressMonitor monitor) throws CoreException {
+			RevCommit previous = findPreviousCommit();
+			if (previous != null)
+				if (resource instanceof IFile) {
+					final ITypedElement base = SaveableCompareEditorInput
+							.createFileElement((IFile) resource);
+					ITypedElement next = CompareUtils
+							.getFileRevisionTypedElement(getRepositoryPath(),
+									previous, repository);
+					CompareEditorInput input = new GitCompareFileRevisionEditorInput(
+							base, next, null);
+					CompareUI.openCompareEditor(input);
+				} else
+					openCompareTreeView(previous);
+			else
+				showNotFoundDialog();
+		}
+
+		private void openCompareTreeView(final RevCommit previous) {
+			final Shell shell = HandlerUtil.getActiveShell(event);
+			shell.getDisplay().asyncExec(new Runnable() {
+
+				public void run() {
+					try {
+						CompareTreeView view = (CompareTreeView) PlatformUI
+								.getWorkbench().getActiveWorkbenchWindow()
+								.getActivePage().showView(CompareTreeView.ID);
+						view.setInput(new IResource[] { resource },
+								previous.name());
+					} catch (PartInitException e) {
+						Activator.handleError(e.getMessage(), e, true);
+					}
+				}
+			});
+		}
+
+		private RevCommit findPreviousCommit() {
+			RevWalk rw = new RevWalk(repository);
+			try {
+				String path = getRepositoryPath();
+				if (path.length() > 0)
+					rw.setTreeFilter(FollowFilter.create(path));
+				RevCommit headCommit = rw.parseCommit(repository.getRef(
+						Constants.HEAD).getObjectId());
+				rw.markStart(headCommit);
+				headCommit = rw.next();
+				if (headCommit != null)
+					return rw.next();
+			} catch (IOException e) {
+				Activator.handleError(e.getMessage(), e, true);
+			} finally {
+				rw.dispose();
+			}
+			return null;
+		}
+
+		private void showNotFoundDialog() {
+			final Shell shell = HandlerUtil.getActiveShell(event);
+			final String message = MessageFormat
+					.format(UIText.CompareWithPreviousActionHandler_MessageRevisionNotFound,
+							resource.getName());
+			shell.getDisplay().asyncExec(new Runnable() {
+
+				public void run() {
+					MessageDialog
+							.openWarning(
+									shell,
+									UIText.CompareWithPreviousActionHandler_TitleRevisionNotFound,
+									message);
+				}
+			});
+		}
+
+		public ISchedulingRule getSchedulingRule() {
+			return resource;
+		}
+	}
+
+	/**
+	 * @see org.eclipse.core.commands.IHandler#execute(org.eclipse.core.commands.ExecutionEvent)
+	 */
+	public Object execute(ExecutionEvent event) throws ExecutionException {
+		Repository repository = getRepository(true, event);
+		if (repository == null)
+			return null;
+
+		IResource[] resources = getSelectedResources(event);
+		if (resources.length == 1)
+			JobUtil.scheduleUserJob(
+					new CompareWithPreviousOperation(event, repository,
+							resources[0]),
+					UIText.CompareWithPreviousActionHandler_TaskGeneratingInput,
+					null);
+		return null;
+	}
+}
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 453ca1c112..86ecfe9c95 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
@@ -567,6 +567,9 @@ CommitMessageViewer_GettingPreviousTagTaskName=Getting previous tag
 CommitMessageViewer_parent=Parent
 CommitMessageViewer_SelectOneCommitMessage=Please select exactly one commit
 CompareWithIndexAction_errorOnAddToIndex=Error during adding to index
+CompareWithPreviousActionHandler_MessageRevisionNotFound=No previous revision of {0} could be found in the repository.
+CompareWithPreviousActionHandler_TaskGeneratingInput=Generating comparison with previous revision
+CompareWithPreviousActionHandler_TitleRevisionNotFound=Previous revision not found
 
 ConfirmationPage_cantConnectToAnyTitle=Can't Connect
 ConfirmationPage_cantConnectToAny=Can't connect to any URI: {0}