Show parents for commits with more than one parent

This adds links to the commit header for each parent allowing
to quickly jump to a parent.

gitg/history/gitg-history.vala

@@ -94,6 +94,24 @@ namespace GitgHistory
 			});
 		}
 
+		public void select(Gitg.Commit commit)
+		{
+			var model = (Gitg.CommitModel)d_main.commit_list_view.model;
+			var path = model.path_from_commit(commit);
+
+			if (path != null)
+			{
+				var sel = d_main.commit_list_view.get_selection();
+				sel.select_path(path);
+
+				d_main.commit_list_view.scroll_to_cell(path, null, true, 0.5f, 0);
+			}
+			else
+			{
+				stderr.printf("Failed to lookup tree path for commit '%s'\n", commit.get_id().to_string());
+			}
+		}
+
 		construct
 		{
 			d_settings = new Settings("org.gnome.gitg.preferences.history");

libgitg-ext/gitg-ext-history.vala

@@ -27,6 +27,8 @@ public interface History : Object, Activity
 
 	public signal void selection_changed();
 	public abstract void foreach_selected(ForeachCommitSelectionFunc func);
+
+  public abstract void select(Gitg.Commit commit);
 }
 
 }

libgitg/gitg-commit-model.vala

@@ -72,6 +72,7 @@ namespace Gitg
 		private uint d_idleid;
 		private Lanes d_lanes;
 		private Ggit.SortMode d_sortmode;
+		private Gee.HashMap<Ggit.OId, int> d_id_hash;
 
 		private Ggit.OId[] d_include;
 		private Ggit.OId[] d_exclude;
@@ -149,6 +150,8 @@ namespace Gitg
 			d_ids = new Commit[0];
 			d_advertized_size = 0;
 
+			d_id_hash = new Gee.HashMap<Ggit.OId, int>();
+
 			emit_started();
 			finished();
 		}
@@ -301,6 +304,11 @@ namespace Gitg
 
 				Timer timer = new Timer();
 
+				lock(d_id_hash)
+				{
+					d_id_hash = new Gee.HashMap<Ggit.OId, int>((i) => { return i.hash(); }, (a, b) => { return a.equal(b); });
+				}
+
 				while (true)
 				{
 					Ggit.OId? id;
@@ -323,6 +331,11 @@ namespace Gitg
 						commit = d_repository.lookup<Commit>(id);
 					} catch { break; }
 
+					lock(d_id_hash)
+					{
+						d_id_hash.set(id, d_ids.length);
+					}
+
 					// Add the id
 					if (d_ids.length == size)
 					{
@@ -538,6 +551,21 @@ namespace Gitg
 			return this[idx];
 		}
 
+		public Gtk.TreePath? path_from_commit(Commit commit)
+		{
+			lock(d_id_hash)
+			{
+				var id = commit.get_id();
+
+				if (!d_id_hash.has_key(id))
+				{
+					return null;
+				}
+
+				return new Gtk.TreePath.from_indices(d_id_hash.get(commit.get_id()));
+			}
+		}
+
 		public Commit? commit_from_path(Gtk.TreePath path)
 		{
 			int[] indices = path.get_indices();

libgitg/gitg-diff-view-request-diff.vala

@@ -240,6 +240,24 @@ namespace Gitg
 				builder.add_string_value(note.get_message());
 			}
 
+			builder.set_member_name("parents");
+			builder.begin_array();
+
+			foreach (var parent in commit.get_parents())
+			{
+				builder.begin_object();
+
+				builder.set_member_name("id");
+				builder.add_string_value(parent.get_id().to_string());
+
+				builder.set_member_name("subject");
+				builder.add_string_value(parent.get_subject());
+
+				builder.end_object();
+			}
+
+			builder.end_array();
+
 			builder.end_object();
 		}
 

libgitg/gitg-diff-view.vala

@@ -39,6 +39,9 @@ namespace Gitg
 						case "loaded":
 							d_view.loaded();
 							break;
+						case "load-parent":
+							d_view.load_parent(parameter("value"));
+							break;
 					}
 
 					return false;
@@ -48,6 +51,8 @@ namespace Gitg
 			}
 		}
 
+		public signal void request_select_commit(string id);
+
 		private Ggit.Diff? d_diff;
 		private Commit? d_commit;
 		private Settings? d_fontsettings;
@@ -118,6 +123,7 @@ namespace Gitg
 		public bool wrap { get; set; default = true; }
 		public bool staged { get; set; default = false; }
 		public bool unstaged { get; set; default = false; }
+		public bool show_parents { get; set; default = false; }
 
 		int d_tab_width;
 
@@ -223,6 +229,7 @@ namespace Gitg
 			o.set_boolean_member("unstaged", unstaged);
 			o.set_boolean_member("debug", Environment.get_variable("GITG_GTK_DIFF_VIEW_DEBUG") != null);
 			o.set_boolean_member("changes_inline", changes_inline);
+			o.set_boolean_member("show_parents", show_parents);
 
 			var strings = new Json.Object();
 
@@ -230,6 +237,7 @@ namespace Gitg
 			strings.set_string_member("unstage", _("unstage"));
 			strings.set_string_member("loading_diff", _("Loading diff…"));
 			strings.set_string_member("notes", _("Notes:"));
+			strings.set_string_member("parents", _("Parents:"));
 
 			o.set_object_member("strings", strings);
 
@@ -527,6 +535,11 @@ namespace Gitg
 			}
 		}
 
+		public void load_parent(string id)
+		{
+			request_select_commit(id);
+		}
+
 		private PatchSet parse_patchset(Json.Node node)
 		{
 			PatchSet ret = new PatchSet();

libgitg/resources/diff-view.css

@@ -48,6 +48,17 @@ img.avatar {
   min-height: 50px;
 }
 
+div.commit .parents .title {
+  font-weight: bold;
+}
+
+div.commit .parents ul {
+  list-style: none;
+  margin-top: 6px;
+  margin-left: 12px;
+  padding-left: 0px;
+}
+
 div.commit {
   padding: 10px;
   font-family: sans-serif;

libgitg/resources/diff-view.html

@@ -45,6 +45,8 @@
             <span class="notes" data-id="notes"></span><br/>
             <span class="note_message" data-id="note_message"></span>
           </p>
+          <p class="parents" data-id="parents">
+          </p>
           <div class="sha1" data-id="sha1"></div>
         </div>
       </div>

libgitg/resources/diff-view.js

@@ -21,11 +21,13 @@ var settings = {
 	debug: false,
 	staged: false,
 	unstaged: false,
+	show_parents: false,
 	strings: {
 		stage: 'stage',
 		unstage: 'unstage',
 		loading_diff: 'Loading diff...',
-		notes: 'Notes:'
+		notes: 'Notes:',
+		parents: 'Parents:'
 	},
 };
 
@@ -163,6 +165,41 @@ function write_commit(content, commit)
 		elems.notes_container.hide();
 	}
 
+	if (commit.parents.length > 1 && settings.show_parents)
+	{
+		var d = $('<div/>');
+
+		d.append($('<div/>', {'class': 'title'}).text(settings.strings.parents));
+
+		var ul = $('<ul/>');
+
+		for (var i = 0; i < commit.parents.length; i++)
+		{
+			var parent = commit.parents[i];
+			var li = $('<li/>');
+
+			var a = $('<a/>', {'href': '#'}).text(parent.id.slice(0, 6) + ': ' + parent.subject);
+			a.on('click', (function(id, e) {
+
+				xhr_get('internal', {'action': 'load-parent', 'value': id});
+				e.preventDefault();
+				e.stopPropagation();
+			}).bind(this, parent.id));
+
+			li.append(a);
+			ul.append(li);
+		}
+
+		d.append(ul);
+
+		elems.parents.html(d);
+		elems.parents.show();
+	}
+	else
+	{
+		elems.parents.hide();
+	}
+
 	// Sha1
 	elems.sha1.text(commit.id);
 

plugins/diff/gitg-diff.vala

@@ -37,6 +37,7 @@ namespace GitgDiff
 			d_sw.show();
 
 			d_diff = new Gitg.DiffView();
+			d_diff.show_parents = true;
 
 			var settings = new Settings("org.gnome.gitg.preferences.diff");
 
@@ -72,6 +73,22 @@ namespace GitgDiff
 
 			history.selection_changed.connect(on_selection_changed);
 			on_selection_changed(history);
+
+			d_diff.request_select_commit.connect((id) => {
+				Gitg.Commit commit;
+
+				try
+				{
+					commit = application.repository.lookup<Gitg.Commit>(new Ggit.OId.from_string(id));
+				}
+				catch (Error e)
+				{
+					stderr.printf("Failed to lookup commit '%s': %s\n", id, e.message);
+					return;
+				}
+
+				history.select(commit);
+			});
 		}
 
 		public string id