[gitg] Bind commit details parent button

[Jesse van den Kieboom <jessevdk src gnome org>]

commit 321310bb2300e9e3e60a8e10850a0561e4ef31b4
Author: Jesse van den Kieboom <jessevdk gnome org>
Date:   Sun Nov 8 20:54:48 2015 +0100

    Bind commit details parent button

 libgitg/gitg-diff-view-commit-details.vala |   18 +++++++++++++++---
 libgitg/gitg-diff-view.vala                |   22 ++++++++++++++++------
 2 files changed, 31 insertions(+), 9 deletions(-)
---
diff --git a/libgitg/gitg-diff-view-commit-details.vala b/libgitg/gitg-diff-view-commit-details.vala
index def2bb9..eec09ca 100644
--- a/libgitg/gitg-diff-view-commit-details.vala
+++ b/libgitg/gitg-diff-view-commit-details.vala
@@ -203,19 +203,29 @@ class Gitg.DiffViewCommitDetails : Gtk.Grid
                var parents = commit.get_parents();
                var first_parent = parents.size == 0 ? null : parents.get(0);
 
-               d_parent_commit = first_parent;
+               parent_commit = first_parent;
 
                if (parents.size > 1)
                {
                        d_grid_parents_container.show();
                        var grp = new SList<Gtk.RadioButton>();
 
+                       Gtk.RadioButton? first = null;
+
                        foreach (var parent in parents)
                        {
                                var pid = parent.get_id().to_string().substring(0, 6);
                                var psubj = parent.get_subject();
 
                                var button = new Gtk.RadioButton.with_label(grp, @"$pid: $psubj");
+
+                               if (first == null)
+                               {
+                                       first = button;
+                               }
+
+                               button.group = first;
+
                                d_parents_map[parent.get_id()] = button;
 
                                button.show();
@@ -223,8 +233,10 @@ class Gitg.DiffViewCommitDetails : Gtk.Grid
 
                                var par = parent;
 
-                               button.activate.connect(() => {
-                                       d_parent_commit = par;
+                               button.toggled.connect(() => {
+                                       if (button.active) {
+                                               parent_commit = par;
+                                       }
                                });
                        }
                }
diff --git a/libgitg/gitg-diff-view.vala b/libgitg/gitg-diff-view.vala
index 770d73e..407c167 100644
--- a/libgitg/gitg-diff-view.vala
+++ b/libgitg/gitg-diff-view.vala
@@ -33,7 +33,6 @@ public class Gitg.DiffView : Gtk.Grid
        private Commit? d_commit;
 
        private Ggit.DiffOptions? d_options;
-       private Ggit.OId? d_parent;
 
        public Ggit.DiffOptions options
        {
@@ -64,7 +63,6 @@ public class Gitg.DiffView : Gtk.Grid
                        d_diff = value;
 
                        d_commit = null;
-                       d_parent = null;
 
                        update();
                }
@@ -79,7 +77,6 @@ public class Gitg.DiffView : Gtk.Grid
                        {
                                d_commit = value;
                                d_diff = null;
-                               d_parent = null;
                        }
 
                        update();
@@ -187,10 +184,18 @@ public class Gitg.DiffView : Gtk.Grid
        }
 
        private ulong d_expanded_notify;
+       private ulong d_parent_commit_notify;
 
        protected override void constructed()
        {
                d_expanded_notify = d_commit_details.notify["expanded"].connect(update_expanded_files);
+
+               d_parent_commit_notify = 
d_commit_details.notify["parent-commit"].connect(parent_commit_changed);
+       }
+
+       private void parent_commit_changed()
+       {
+               update();
        }
 
        private void update_expanded_files()
@@ -223,16 +228,22 @@ public class Gitg.DiffView : Gtk.Grid
 
                if (d_commit != null)
                {
+                       SignalHandler.block(d_commit_details, d_parent_commit_notify);
+                       d_commit_details.commit = d_commit;
+                       SignalHandler.unblock(d_commit_details, d_parent_commit_notify);
+
                        int parent = 0;
                        var parents = d_commit.get_parents();
 
-                       if (d_parent != null)
+                       var parent_commit = d_commit_details.parent_commit;
+
+                       if (parent_commit != null)
                        {
                                for (var i = 0; i < parents.size; i++)
                                {
                                        var id = parents.get_id(i);
 
-                                       if (id.equal(d_parent))
+                                       if (id.equal(parent_commit.get_id()))
                                        {
                                                parent = i;
                                                break;
@@ -241,7 +252,6 @@ public class Gitg.DiffView : Gtk.Grid
                        }
 
                        d_diff = d_commit.get_diff(options, parent);
-                       d_commit_details.commit = d_commit;
                        d_commit_details.show();
                }
                else