[EGIT PATCH] Show diff when double-clicking on file in commit dialog

[Robin Stocker <robin@nibor.org>]

It only compares the index version to the working tree version for now.
So if the file was already added to the index, the diff is empty. What
it should show is the diff that will be in the commit.

Signed-off-by: Robin Stocker <robin@nibor.org>
---

Hi,

An essential feature I miss in EGit at the moment (apart from the
synchronize view [1]) is seeing what changes one is about to commit. In
the Subclipse SVN plugin one can double-click a file in the commit
dialog and the diff is shown.

This patch is a first step for adding this to EGit. It only compares the
index version to the working tree version as I couldn't figure out an
easy way to get the HEAD version.

It's more a proof of concept than a final patch. What do you think?

[1] Someone is working on the synchronize view:
    http://github.com/yanns/egit/commits/compare-with-index

-- Robin, a different one :)

 .../egit/ui/internal/dialogs/CommitDialog.java     |   40 ++++++++++++++++++++
 1 files changed, 40 insertions(+), 0 deletions(-)

diff --git a/org.spearce.egit.ui/src/org/spearce/egit/ui/internal/dialogs/CommitDialog.java b/org.spearce.egit.ui/src/org/spearce/egit/ui/internal/dialogs/CommitDialog.java
index 8b7fe45..6999e87 100644
--- a/org.spearce.egit.ui/src/org/spearce/egit/ui/internal/dialogs/CommitDialog.java
+++ b/org.spearce.egit.ui/src/org/spearce/egit/ui/internal/dialogs/CommitDialog.java
@@ -18,6 +18,8 @@
 import java.util.Comparator;
 import java.util.Iterator;
 
+import org.eclipse.compare.CompareUI;
+import org.eclipse.compare.ITypedElement;
 import org.eclipse.core.resources.IFile;
 import org.eclipse.core.resources.IProject;
 import org.eclipse.jface.dialogs.Dialog;
@@ -52,9 +54,17 @@
 import org.eclipse.swt.widgets.Table;
 import org.eclipse.swt.widgets.TableColumn;
 import org.eclipse.swt.widgets.Text;
+import org.eclipse.team.core.RepositoryProvider;
+import org.eclipse.team.core.history.IFileHistory;
+import org.eclipse.team.core.history.IFileRevision;
+import org.eclipse.team.internal.ui.history.FileRevisionTypedElement;
 import org.eclipse.ui.model.WorkbenchLabelProvider;
+import org.spearce.egit.core.GitProvider;
+import org.spearce.egit.core.internal.storage.GitFileHistoryProvider;
+import org.spearce.egit.core.internal.storage.GitFileRevision;
 import org.spearce.egit.core.project.RepositoryMapping;
 import org.spearce.egit.ui.UIText;
+import org.spearce.egit.ui.internal.GitCompareFileRevisionEditorInput;
 import org.spearce.jgit.lib.Constants;
 import org.spearce.jgit.lib.GitIndex;
 import org.spearce.jgit.lib.PersonIdent;
@@ -262,6 +272,8 @@ public void modifyText(ModifyEvent e) {
 		resourcesTable.setLayoutData(GridDataFactory.fillDefaults().hint(600,
 				200).span(2,1).grab(true, true).create());
 
+		resourcesTable.addSelectionListener(new CommitItemSelectionListener());
+
 		resourcesTable.setHeaderVisible(true);
 		TableColumn statCol = new TableColumn(resourcesTable, SWT.LEFT);
 		statCol.setText(UIText.CommitDialog_Status);
@@ -505,6 +517,34 @@ public void widgetSelected(SelectionEvent e) {
 
 	}
 
+	class CommitItemSelectionListener extends SelectionAdapter {
+
+		public void widgetDefaultSelected(SelectionEvent e) {
+			IStructuredSelection selection = (IStructuredSelection) filesViewer.getSelection();
+
+			CommitItem commitItem = (CommitItem) selection.getFirstElement();
+			if (commitItem == null) {
+				return;
+			}
+
+			IProject project = commitItem.file.getProject();
+			GitProvider provider = (GitProvider) RepositoryProvider.getProvider(project);
+			GitFileHistoryProvider fileHistoryProvider = (GitFileHistoryProvider) provider.getFileHistoryProvider();
+
+			IFileHistory fileHistory = fileHistoryProvider.getFileHistoryFor(commitItem.file, 0, null);
+
+			IFileRevision baseFile = fileHistory.getFileRevision(GitFileRevision.INDEX);
+			IFileRevision nextFile = fileHistoryProvider.getWorkspaceFileRevision(commitItem.file);
+
+			ITypedElement base = new FileRevisionTypedElement(baseFile);
+			ITypedElement next = new FileRevisionTypedElement(nextFile);
+
+			GitCompareFileRevisionEditorInput input = new GitCompareFileRevisionEditorInput(base, next, null);
+			CompareUI.openCompareDialog(input);
+		}
+
+	}
+
 	@Override
 	protected void okPressed() {
 		commitMessage = commitText.getText();
-- 
1.6.1.2