[gnome-documents] all: add a queue for sparql select queries

[Cosimo Cecchi <cosimoc src gnome org>]

commit d6404414c7a12f0313d69ab5af30bcf1633f4e34
Author: Cosimo Cecchi <cosimoc gnome org>
Date:   Tue Nov 8 20:36:58 2011 -0500

    all: add a queue for sparql select queries
    
    TrackerSparqlConnection doesn't really like performing another
    concurrent query while the first one hasn't yet returned, so add a
    little queue to order the query requests with.
    This dramatically improves smoothness while refreshing the model.

 src/application.js       |    1 +
 src/changeMonitor.js     |    2 +-
 src/collections.js       |    2 +-
 src/documents.js         |    7 ++-----
 src/global.js            |    1 +
 src/offsetController.js  |    6 +++++-
 src/trackerController.js |   45 ++++++++++++++++++++++++++++++++++++++++++---
 7 files changed, 53 insertions(+), 11 deletions(-)
---
diff --git a/src/application.js b/src/application.js
index b4a617f..a5bd8f1 100644
--- a/src/application.js
+++ b/src/application.js
@@ -144,6 +144,7 @@ Application.prototype = {
                             this.quit();
                         }
 
+                        Global.connectionQueue = new TrackerController.TrackerConnectionQueue();
                         Global.sourceManager = new Sources.SourceManager();
                         Global.searchMatchManager = new Searchbar.SearchMatchManager();
                         Global.searchTypeManager = new Searchbar.SearchTypeManager();
diff --git a/src/changeMonitor.js b/src/changeMonitor.js
index 6f85ce6..3276908 100644
--- a/src/changeMonitor.js
+++ b/src/changeMonitor.js
@@ -109,7 +109,7 @@ TrackerChangeMonitor.prototype = {
     _updateIterator: function(event, isDelete) {
         // we're only interested in the resource URN, as we will query for
         // the item properties again, but we still want to compress deletes and inserts
-        Global.connection.query_async(
+        Global.connectionQueue.add(
             ('SELECT tracker:uri(%d) tracker:uri(%d) {}').format(event[1], event[2]),
             null, Lang.bind(this,
                 function(object, res) {
diff --git a/src/collections.js b/src/collections.js
index 4afae10..b951e6d 100644
--- a/src/collections.js
+++ b/src/collections.js
@@ -103,7 +103,7 @@ CollectionManager.prototype = {
 
     _refreshCollections: function() {
         this._currentQuery = Global.queryBuilder.buildCollectionsQuery();
-        Global.connection.query_async(this._currentQuery.sparql, null, Lang.bind(this,
+        Global.connectionQueue.add(this._currentQuery.sparql, null, Lang.bind(this,
             function(object, res) {
                 try {
                     let cursor = object.query_finish(res);
diff --git a/src/documents.js b/src/documents.js
index 424697e..f10bee5 100644
--- a/src/documents.js
+++ b/src/documents.js
@@ -82,7 +82,7 @@ DocCommon.prototype = {
     refresh: function() {
         let query = Global.queryBuilder.buildSingleQuery(this.id);
 
-        Global.connection.query_async(query.sparql, null, Lang.bind(this,
+        Global.connectionQueue.add(query.sparql, null, Lang.bind(this,
             function(object, res) {
                 let cursor = null;
 
@@ -576,7 +576,7 @@ DocumentManager.prototype = {
     _onDocumentCreated: function(urn) {
         let query = Global.queryBuilder.buildSingleQuery(urn);
 
-        Global.connection.query_async(query.sparql, null, Lang.bind(this,
+        Global.connectionQueue.add(query.sparql, null, Lang.bind(this,
             function(object, res) {
                 let cursor = null;
 
@@ -688,9 +688,6 @@ DocumentModel.prototype = {
                                  doc.title, doc.author,
                                  doc.pixbuf, doc.mtime);
             }));
-
-        while (Gtk.events_pending())
-            Gtk.main_iteration();
     },
 
     documentRemoved: function(doc) {
diff --git a/src/global.js b/src/global.js
index 029121e..52053dd 100644
--- a/src/global.js
+++ b/src/global.js
@@ -22,6 +22,7 @@
 let application = null;
 let categoryManager = null;
 let connection = null;
+let connectionQueue = null;
 let documentManager = null;
 let errorHandler = null;
 let goaClient = null;
diff --git a/src/offsetController.js b/src/offsetController.js
index 3c5e7cf..5160225 100644
--- a/src/offsetController.js
+++ b/src/offsetController.js
@@ -20,10 +20,14 @@
  */
 
 const Lang = imports.lang;
+const Mainloop = imports.mainloop;
 const Signals = imports.signals;
 
 const Global = imports.global;
 
+const Gio = imports.gi.Gio;
+const GLib = imports.gi.GLib;
+
 const _OFFSET_STEP = 50;
 
 function OffsetController() {
@@ -46,7 +50,7 @@ OffsetController.prototype = {
     resetItemCount: function() {
         let query = Global.queryBuilder.buildCountQuery();
 
-        Global.connection.query_async
+        Global.connectionQueue.add
             (query.sparql, null, Lang.bind(this,
                 function(object, res) {
                     let cursor = null;
diff --git a/src/trackerController.js b/src/trackerController.js
index 67697a5..80f34f3 100644
--- a/src/trackerController.js
+++ b/src/trackerController.js
@@ -30,9 +30,49 @@ const Query = imports.query;
 const Utils = imports.utils;
 
 const Gio = imports.gi.Gio;
+const GLib = imports.gi.GLib;
 
 const MINER_REFRESH_TIMEOUT = 60; /* seconds */
 
+function TrackerConnectionQueue() {
+    this._init();
+}
+
+TrackerConnectionQueue.prototype = {
+    _init: function() {
+        this._queue = [];
+        this._running = false;
+    },
+
+    add: function(query, cancellable, callback) {
+        let params = { query: query,
+                       cancellable: cancellable,
+                       callback: callback };
+        this._queue.push(params);
+
+        this._checkQueue();
+    },
+
+    _checkQueue: function() {
+        if (this._running)
+            return;
+
+        if (!this._queue.length)
+            return;
+
+        let params = this._queue.shift();
+        this._running = true;
+        Global.connection.query_async(params.query, params.cancellable,
+                                      Lang.bind(this, this._queueCollector, params));
+    },
+
+    _queueCollector: function(connection, res, params) {
+        params.callback(connection, res);
+        this._running = false;
+        this._checkQueue();
+    }
+};
+
 function TrackerController() {
     this._init();
 }
@@ -43,7 +83,6 @@ TrackerController.prototype = {
         this._cancellable = new Gio.Cancellable();
         this._queryQueued = false;
         this._querying = false;
-
         // startup a refresh of the gdocs cache
         this._miner = new GDataMiner.GDataMiner();
         this._refreshMinerNow();
@@ -143,8 +182,8 @@ TrackerController.prototype = {
         this._cancellable.reset();
 
         this._setQueryStatus(true);
-        Global.connection.query_async(this._currentQuery.sparql,
-                                      this._cancellable, Lang.bind(this, this._onQueryExecuted));
+        Global.connectionQueue.add(this._currentQuery.sparql,
+                                   this._cancellable, Lang.bind(this, this._onQueryExecuted));
     },
 
     _refresh: function() {