Start the switch-to menu with recently used branch names first

This assures that you rarely need to use the Other... menu item.
Branch names are still ordered alphabetically. If only a few
recently used branch names exist, more entries are added as
before this change.

Depend on JGit change I91c7e08c4afd2562df2226887a933d93c78a0371

Change-Id: I5e666fb37d70c078eac816af8d66dcc000b16be8
Signed-off-by: Robin Rosenberg <robin.rosenberg@dewire.com>
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>

1 files changed, 69 insertions, 26 deletions

diff --git a/org.eclipse.egit.ui/src/org/eclipse/egit/ui/internal/actions/SwitchToMenu.java b/org.eclipse.egit.ui/src/org/eclipse/egit/ui/internal/actions/SwitchToMenu.java
index 73a1c1c818..dfca6555e7 100644
--- a/org.eclipse.egit.ui/src/org/eclipse/egit/ui/internal/actions/SwitchToMenu.java
+++ b/org.eclipse.egit.ui/src/org/eclipse/egit/ui/internal/actions/SwitchToMenu.java
@@ -9,9 +9,10 @@
 package org.eclipse.egit.ui.internal.actions;
 
 import java.io.IOException;
+import java.util.List;
 import java.util.Map;
-import java.util.TreeMap;
 import java.util.Map.Entry;
+import java.util.TreeMap;
 
 import org.eclipse.core.resources.IProject;
 import org.eclipse.core.runtime.IAdaptable;
@@ -27,6 +28,9 @@ import org.eclipse.jface.viewers.IStructuredSelection;
 import org.eclipse.jgit.lib.Constants;
 import org.eclipse.jgit.lib.Ref;
 import org.eclipse.jgit.lib.Repository;
+import org.eclipse.jgit.storage.file.CheckoutEntry;
+import org.eclipse.jgit.storage.file.ReflogEntry;
+import org.eclipse.jgit.storage.file.ReflogReader;
 import org.eclipse.swt.SWT;
 import org.eclipse.swt.events.SelectionAdapter;
 import org.eclipse.swt.events.SelectionEvent;
@@ -101,37 +105,57 @@ public class SwitchToMenu extends ContributionItem implements
 			}
 		});
 		new MenuItem(menu, SWT.SEPARATOR);
-		String currentBranch;
-		Map<String, Ref> localBranches;
 		try {
-			currentBranch = mapping.getRepository().getFullBranch();
-			localBranches = mapping.getRepository().getRefDatabase().getRefs(
+			String currentBranch = mapping.getRepository().getFullBranch();
+			Map<String, Ref> localBranches = mapping.getRepository().getRefDatabase().getRefs(
 					Constants.R_HEADS);
-			// sort by name
 			TreeMap<String, Ref> sortedRefs = new TreeMap<String, Ref>();
-			sortedRefs.putAll(localBranches);
+
+			// Add the MAX_NUM_MENU_ENTRIES most recently used branches first
+			List<ReflogEntry> reflogEntries = new ReflogReader(
+					mapping.getRepository(), Constants.HEAD)
+					.getReverseEntries();
+			for (ReflogEntry entry : reflogEntries) {
+				CheckoutEntry checkout = entry.parseCheckout();
+				if (checkout != null) {
+					Ref ref = localBranches.get(checkout.getFromBranch());
+					if (ref != null)
+						if (sortedRefs.size() < MAX_NUM_MENU_ENTRIES)
+							sortedRefs.put(checkout.getFromBranch(), ref);
+					ref = localBranches.get(checkout.getToBranch());
+					if (ref != null)
+						if (sortedRefs.size() < MAX_NUM_MENU_ENTRIES)
+							sortedRefs.put(checkout.getToBranch(), ref);
+				}
+			}
+
+			// Add the recently used branches to the menu, in alphabetical order
 			int itemCount = 0;
 			for (final Entry<String, Ref> entry : sortedRefs.entrySet()) {
 				itemCount++;
-				// protect ourselves against a huge sub-menu
-				if (itemCount > MAX_NUM_MENU_ENTRIES)
-					break;
-				MenuItem item = new MenuItem(menu, SWT.PUSH);
-				item.setText(entry.getKey());
-				boolean checkedOut = currentBranch.equals(entry.getValue()
-						.getName());
-				if (checkedOut)
-					item.setImage(checkedOutImage);
-				else
-					item.setImage(branchImage);
-				item.setEnabled(!checkedOut);
-				item.addSelectionListener(new SelectionAdapter() {
-					@Override
-					public void widgetSelected(SelectionEvent e) {
-						BranchOperationUI.checkout(repository,
-								entry.getValue().getName()).start();
-					}
-				});
+				final String shortName = entry.getKey();
+				final String fullName = entry.getValue().getName();
+				createMenuItem(menu, repository, currentBranch, fullName, shortName);
+				// Do not duplicate branch names
+				localBranches.remove(shortName);
+			}
+
+			if (itemCount < MAX_NUM_MENU_ENTRIES && itemCount > 0 && sortedRefs.size() > 0) {
+				// Now add more other branches if we have only a few branch switches
+				// Sort the remaining local branches
+				sortedRefs.clear();
+				sortedRefs.putAll(localBranches);
+				// A separator between recently used branches and other branches is nice
+				new MenuItem(menu, SWT.SEPARATOR);
+				for (final Entry<String, Ref> entry : sortedRefs.entrySet()) {
+					itemCount++;
+					// protect ourselves against a huge sub-menu
+					if (itemCount > MAX_NUM_MENU_ENTRIES)
+						break;
+					final String fullName = entry.getValue().getName();
+					final String shortName = entry.getKey();
+					createMenuItem(menu, repository, fullName, shortName, shortName);
+				}
 			}
 			if (localBranches.size() > 0)
 				new MenuItem(menu, SWT.SEPARATOR);
@@ -148,6 +172,25 @@ public class SwitchToMenu extends ContributionItem implements
 		}
 	}
 
+	private void createMenuItem(Menu menu, final Repository repository,
+			String currentBranch, final String fullName, String shortName) {
+		final MenuItem item = new MenuItem(menu, SWT.PUSH);
+		item.setText(shortName);
+		boolean checkedOut = currentBranch.equals(fullName);
+		if (checkedOut)
+			item.setImage(checkedOutImage);
+		else
+			item.setImage(branchImage);
+		item.setEnabled(!checkedOut);
+		item.addSelectionListener(new SelectionAdapter() {
+			@Override
+			public void widgetSelected(SelectionEvent e) {
+				BranchOperationUI.checkout(repository, fullName)
+						.start();
+			}
+		});
+	}
+
 	@Override
 	public boolean isDynamic() {
 		return true;