[gthumb] browser: load the metadata after a timeout

[Paolo Bacchilega <paobac src gnome org>]

commit 461e2fb2cb13f3579ffba507c1debfcd1526b225
Author: Paolo Bacchilega <paobac src gnome org>
Date:   Sat Sep 14 18:21:19 2013 +0200

    browser: load the metadata after a timeout

 gthumb/gth-browser.c |   79 +++++++++++++++++++++++++++++++++++++------------
 1 files changed, 59 insertions(+), 20 deletions(-)
---
diff --git a/gthumb/gth-browser.c b/gthumb/gth-browser.c
index a46cd5d..2dc1190 100644
--- a/gthumb/gth-browser.c
+++ b/gthumb/gth-browser.c
@@ -66,6 +66,7 @@
 #define GTH_BROWSER_CALLBACK(f) ((GthBrowserCallback) (f))
 #define MAX_HISTORY_LENGTH 15
 #define LOAD_FILE_DELAY 150
+#define LOAD_METADATA_DELAY 150
 #define HIDE_MOUSE_DELAY 1000
 #define MOTION_THRESHOLD 0
 #define UPDATE_SELECTION_DELAY 200
@@ -170,6 +171,7 @@ struct _GthBrowserPrivate {
        GList             *load_data_queue;
        GList             *load_file_data_queue;
        guint              load_file_timeout;
+       guint              load_metadata_timeout;
        char              *list_attributes;
        gboolean           constructed;
        guint              construct_step2_event;
@@ -4306,7 +4308,7 @@ gth_browser_init (GthBrowser *browser)
        browser->priv = G_TYPE_INSTANCE_GET_PRIVATE (browser, GTH_TYPE_BROWSER, GthBrowserPrivate);
        browser->priv->viewer_pages = NULL;
        browser->priv->viewer_page = NULL;
-       browser->priv->image_preloader = gth_image_preloader_new (GTH_LOAD_POLICY_TWO_STEPS, 10);
+       browser->priv->image_preloader = gth_image_preloader_new ();
        browser->priv->progress_dialog = NULL;
        browser->priv->named_dialogs = g_hash_table_new (g_str_hash, g_str_equal);
        for (i = 0; i < GTH_BROWSER_N_PAGES; i++)
@@ -4336,6 +4338,7 @@ gth_browser_init (GthBrowser *browser)
        browser->priv->load_data_queue = NULL;
        browser->priv->load_file_data_queue = NULL;
        browser->priv->load_file_timeout = 0;
+       browser->priv->load_metadata_timeout = 0;
        browser->priv->list_attributes = NULL;
        browser->priv->constructed = FALSE;
        browser->priv->selection_changed_event = 0;
@@ -5697,6 +5700,16 @@ load_file_data_new (GthBrowser  *browser,
        data->view = view;
        data->cancellable = g_cancellable_new ();
 
+       /* cancel all other file data operations */
+       {
+               GList *scan;
+
+               for (scan = browser->priv->load_file_data_queue; scan; scan = scan->next) {
+                       LoadFileData *data = scan->data;
+                       g_cancellable_cancel (data->cancellable);
+               }
+       }
+
        browser->priv->load_file_data_queue = g_list_prepend (browser->priv->load_file_data_queue, data);
 
        return data;
@@ -5822,6 +5835,27 @@ file_metadata_ready_cb (GList    *files,
 }
 
 
+static gboolean
+load_metadata_cb (gpointer user_data)
+{
+       LoadFileData *data = user_data;
+       GList        *files;
+
+       load_file_data_ref (data);
+       files = g_list_prepend (NULL, data->browser->priv->current_file->file);
+       _g_query_all_metadata_async (files,
+                                    GTH_LIST_DEFAULT,
+                                    "*",
+                                    data->cancellable,
+                                    file_metadata_ready_cb,
+                                    data);
+
+       g_list_free (files);
+
+       return FALSE;
+}
+
+
 static void
 gth_viewer_page_file_loaded_cb (GthViewerPage *viewer_page,
                                GthFileData   *file_data,
@@ -5830,7 +5864,6 @@ gth_viewer_page_file_loaded_cb (GthViewerPage *viewer_page,
 {
        GthBrowser   *browser = user_data;
        LoadFileData *data;
-       GList        *files;
 
        if ((browser->priv->current_file == NULL) || ! g_file_equal (file_data->file, 
browser->priv->current_file->file))
                return;
@@ -5864,16 +5897,15 @@ gth_viewer_page_file_loaded_cb (GthViewerPage *viewer_page,
                gth_browser_set_shrink_wrap_viewer (browser, TRUE);
        }
 
-       data = load_file_data_new (browser, browser->priv->current_file, FALSE);
-       files = g_list_prepend (NULL, browser->priv->current_file->file);
-       _g_query_all_metadata_async (files,
-                                    GTH_LIST_DEFAULT,
-                                    "*",
-                                    data->cancellable,
-                                    file_metadata_ready_cb,
-                                    data);
+       if (browser->priv->load_metadata_timeout != 0)
+               g_source_remove (browser->priv->load_metadata_timeout);
 
-       g_list_free (files);
+       data = load_file_data_new (browser, browser->priv->current_file, FALSE);
+       browser->priv->load_metadata_timeout = g_timeout_add_full (G_PRIORITY_DEFAULT,
+                                                                  LOAD_METADATA_DELAY,
+                                                                  load_metadata_cb,
+                                                                  data,
+                                                                  (GDestroyNotify) load_file_data_unref);
 }
 
 
@@ -6007,26 +6039,28 @@ gth_browser_load_file (GthBrowser  *browser,
 
        _gth_browser_hide_infobar (browser);
 
-       data = load_file_data_new (browser, file_data, view);
+       if (browser->priv->load_file_timeout != 0) {
+               g_source_remove (browser->priv->load_file_timeout);
+               browser->priv->load_file_timeout = 0;
+       }
 
+       if (browser->priv->load_metadata_timeout != 0) {
+               g_source_remove (browser->priv->load_metadata_timeout);
+               browser->priv->load_metadata_timeout = 0;
+       }
+
+       data = load_file_data_new (browser, file_data, view);
        if (view) {
-               if (browser->priv->load_file_timeout != 0) {
-                       g_source_remove (browser->priv->load_file_timeout);
-                       browser->priv->load_file_timeout = 0;
-               }
                load_file_delayed_cb (data);
                load_file_data_unref (data);
        }
-       else {
-               if (browser->priv->load_file_timeout != 0)
-                       g_source_remove (browser->priv->load_file_timeout);
+       else
                browser->priv->load_file_timeout =
                                g_timeout_add_full (G_PRIORITY_DEFAULT,
                                                    LOAD_FILE_DELAY,
                                                    load_file_delayed_cb,
                                                    data,
                                                    (GDestroyNotify) load_file_data_unref);
-       }
 }
 
 
@@ -6355,6 +6389,11 @@ _gth_browser_cancel (GthBrowser *browser,
                browser->priv->load_file_timeout = 0;
        }
 
+       if (browser->priv->load_metadata_timeout != 0) {
+               g_source_remove (browser->priv->load_metadata_timeout);
+               browser->priv->load_metadata_timeout = 0;
+       }
+
        for (scan = browser->priv->load_data_queue; scan; scan = scan->next) {
                LoadData *data = scan->data;