[blame] Follow in history only if linking with selection enabled

When navigating inside an editor showing revision information, EGit
updates the history view to show the commit corresponding to the
current text position. Do so only if "Link with Editor and Selection"
is activated for the history view.

Unfortunately there is no API to determine whether linking is enabled.
I've chosen to query the corresponding preference from the Team UI
plug-in.

Bug: 572886
Change-Id: Ied12d17b5eeeb73dd6391e66b1c064b33375e084
Signed-off-by: Thomas Wolf <thomas.wolf@paranor.ch>

2 files changed, 21 insertions, 0 deletions

diff --git a/org.eclipse.egit.ui/src/org/eclipse/egit/ui/internal/blame/BlameOperation.java b/org.eclipse.egit.ui/src/org/eclipse/egit/ui/internal/blame/BlameOperation.java
index 22a1f5260d..90ea2709be 100644
--- a/org.eclipse.egit.ui/src/org/eclipse/egit/ui/internal/blame/BlameOperation.java
+++ b/org.eclipse.egit.ui/src/org/eclipse/egit/ui/internal/blame/BlameOperation.java
@@ -33,6 +33,7 @@ import org.eclipse.egit.core.op.IEGitOperation;
 import org.eclipse.egit.ui.Activator;
 import org.eclipse.egit.ui.UIPreferences;
 import org.eclipse.egit.ui.internal.EgitUiEditorUtils;
+import org.eclipse.egit.ui.internal.history.GitHistoryPage;
 import org.eclipse.egit.ui.internal.history.HistoryPageInput;
 import org.eclipse.egit.ui.internal.revision.FileRevisionEditorInput;
 import org.eclipse.jface.text.BadLocationException;
@@ -149,6 +150,10 @@ public class BlameOperation implements IEGitOperation {
 			if (!(first instanceof BlameRevision))
 				return;
 
+			if (!GitHistoryPage.isLinkingEnabled()) {
+				return;
+			}
+
 			IHistoryView part = (IHistoryView) PlatformUI.getWorkbench()
 					.getActiveWorkbenchWindow().getActivePage()
 					.findView(IHistoryView.VIEW_ID);
diff --git a/org.eclipse.egit.ui/src/org/eclipse/egit/ui/internal/history/GitHistoryPage.java b/org.eclipse.egit.ui/src/org/eclipse/egit/ui/internal/history/GitHistoryPage.java
index 6e6ed567c5..0c4ae11c5c 100644
--- a/org.eclipse.egit.ui/src/org/eclipse/egit/ui/internal/history/GitHistoryPage.java
+++ b/org.eclipse.egit.ui/src/org/eclipse/egit/ui/internal/history/GitHistoryPage.java
@@ -45,6 +45,7 @@ import org.eclipse.core.runtime.IPath;
 import org.eclipse.core.runtime.IProgressMonitor;
 import org.eclipse.core.runtime.IStatus;
 import org.eclipse.core.runtime.Path;
+import org.eclipse.core.runtime.Platform;
 import org.eclipse.core.runtime.Status;
 import org.eclipse.core.runtime.SubMonitor;
 import org.eclipse.core.runtime.jobs.ISchedulingRule;
@@ -182,6 +183,21 @@ import org.eclipse.ui.texteditor.IUpdate;
 public class GitHistoryPage extends HistoryPage implements RefsChangedListener,
 		TableLoader, IShowInSource, IShowInTargetList {
 
+	private static final String TEAM_UI_PLUGIN_ID = "org.eclipse.team.ui"; //$NON-NLS-1$
+
+	private static final String TEAM_UI_LINKING_PREFERENCE = "pref_generichistory_view_linking"; //$NON-NLS-1$
+
+	/**
+	 * Tells whether "Link with Editor and Selection" is currently enabled in
+	 * the history view.
+	 *
+	 * @return {@code true} if linking is enabled, {@code false} otherwise.
+	 */
+	public static boolean isLinkingEnabled() {
+		return Platform.getPreferencesService().getBoolean(TEAM_UI_PLUGIN_ID,
+				TEAM_UI_LINKING_PREFERENCE, false, null);
+	}
+
 	private static final int INITIAL_ITEM = -1;
 
 	private static final String P_REPOSITORY = "GitHistoryPage.Repository"; //$NON-NLS-1$