[anjuta] dir-project: Load big projects without errors and without blocking the GUI

[Sebastien Granjoux <sgranjoux src gnome org>]

commit bbc0d2d152289e82075a8a10b5cc991aaf0aee47
Author: Sébastien Granjoux <seb sfo free fr>
Date:   Mon Apr 28 20:55:57 2014 +0200

    dir-project: Load big projects without errors and without blocking the GUI
    
    Previously the plugin was opening recursively all directories of the project
    leading to errors due to the limited number of handles (around 1000) and freeze
    in the GUI when returning to the initial caller.
    
    Now, after opening a few directories, the plugin is waiting a few ms.

 plugins/dir-project/dir-project.c |   92 +++++++++++++++++++++++++++++++------
 1 files changed, 77 insertions(+), 15 deletions(-)
---
diff --git a/plugins/dir-project/dir-project.c b/plugins/dir-project/dir-project.c
index cc6f158..3331bbd 100644
--- a/plugins/dir-project/dir-project.c
+++ b/plugins/dir-project/dir-project.c
@@ -608,7 +608,15 @@ typedef struct {
 } DirData;
 
 /* the number of files to enumerate each time */
-#define NUM_FILES 10
+#define NUM_FILES 256
+
+/* The maximum number of directories read at the same time */
+#define MAX_OPEN_DIRECTORIES  8
+
+/* The number of ms to stop if we reach the open directory limit */
+#define TIMEOUT_OPEN_DIRECTORIES  64
+
+static gint open_directories = 0;
 
 static void
 dir_project_load_directory_callback (GObject      *source_object,
@@ -626,6 +634,8 @@ dir_project_load_directory_callback (GObject      *source_object,
                GList *removed = NULL;
 
                /* either we are finished or an error occured */
+               g_object_unref (enumerator);
+               open_directories--;
                anjuta_project_node_clear_state (data->parent, ANJUTA_PROJECT_LOADING);
                if (err != NULL) {
                        g_signal_emit_by_name (data->proj, "node-loaded", data->parent, err);
@@ -656,7 +666,6 @@ dir_project_load_directory_callback (GObject      *source_object,
                g_list_free (removed);
                g_object_unref (data->parent);
                g_slice_free (DirData, data);
-               g_object_unref (enumerator);
 
                return;
        }
@@ -748,23 +757,76 @@ dir_project_load_directory_callback (GObject      *source_object,
                                            dir_project_load_directory_callback, data);
 }
 
-/* Public functions
- *---------------------------------------------------------------------------*/
+static gboolean dir_project_enumerate_directory (DirData* data);
 
-static AnjutaProjectNode *
-dir_project_load_directory (DirProject *project, AnjutaProjectNode *parent, GError **error)
+static void
+dir_project_enumerate_directory_callback (GObject      *source_object,
+                                          GAsyncResult *res,
+                                          gpointer      user_data)
 {
+       GFile *file = G_FILE(source_object);
+       GError *err = NULL;
+       DirData *data = (DirData *) user_data;
        GFileEnumerator *enumerator;
 
-       enumerator = g_file_enumerate_children (parent->file,
-           G_FILE_ATTRIBUTE_STANDARD_NAME,
-           G_FILE_QUERY_INFO_NOFOLLOW_SYMLINKS,
-           NULL,
-           error);
-
+       enumerator = g_file_enumerate_children_finish (file, res, &err);
        if (enumerator == NULL)
-               return parent;
+       {
+               open_directories--;
+               if (err != NULL) {
+                       if (g_error_matches (err, G_IO_ERROR, G_IO_ERROR_TOO_MANY_OPEN_FILES))
+                       {
+                               /* Retry later */
+                               dir_project_enumerate_directory (data);
+                       }
+                       else
+                       {
+                               g_signal_emit_by_name (data->proj, "node-loaded", data->parent, err);
+                       }
+                       g_error_free (err);
+               }
+       }
+       else
+       {
+               g_file_enumerator_next_files_async (enumerator, NUM_FILES, G_PRIORITY_DEFAULT_IDLE, NULL,
+                                                   dir_project_load_directory_callback, data);
+       }
+}
+
+static gboolean
+dir_project_enumerate_directory (DirData* data)
+{
+       /* Limit the number of open directory to avoid the error
+        * G_IO_ERROR_TOO_MANY_OPEN_FILES in other part of Anjuta.*/
+       if (open_directories < MAX_OPEN_DIRECTORIES)
+       {
+               open_directories++;
+               g_file_enumerate_children_async (data->parent->file,
+                                                G_FILE_ATTRIBUTE_STANDARD_NAME,
+                                                G_FILE_QUERY_INFO_NOFOLLOW_SYMLINKS,
+                                                G_PRIORITY_DEFAULT_IDLE,
+                                                NULL,
+                                                dir_project_enumerate_directory_callback, data);
+       }
+       else
+       {
+               g_timeout_add_full (G_PRIORITY_DEFAULT_IDLE,
+                                   TIMEOUT_OPEN_DIRECTORIES,
+                                   (GSourceFunc)dir_project_enumerate_directory,
+                                   data,
+                                   NULL);
+       }
 
+       return FALSE;
+}
+
+
+/* Public functions
+ *---------------------------------------------------------------------------*/
+
+static AnjutaProjectNode *
+dir_project_load_directory (DirProject *project, AnjutaProjectNode *parent, GError **error)
+{
        /* mark all children as loading so we can remove them if no longer relevant */
        AnjutaProjectNode *node;
        for (node = anjuta_project_node_first_child (parent);
@@ -778,8 +840,7 @@ dir_project_load_directory (DirProject *project, AnjutaProjectNode *parent, GErr
        data->proj = project;
        data->parent = g_object_ref (parent);
 
-       g_file_enumerator_next_files_async (enumerator, NUM_FILES, G_PRIORITY_DEFAULT_IDLE, NULL,
-                                           dir_project_load_directory_callback, data);
+       dir_project_enumerate_directory (data);
 
        anjuta_project_node_set_state (parent, ANJUTA_PROJECT_LOADING);
        return parent;
@@ -814,6 +875,7 @@ dir_project_load_root (DirProject *project, GError **error)
        project->sources = dir_push_pattern_list (NULL, g_object_ref (root_file), source_file, FALSE, NULL);
        g_object_unref (source_file);
 
+       open_directories = 0;
        dir_group_node_set_file (ANJUTA_DIR_GROUP_NODE (project), root_file, G_OBJECT (project));
        dir_project_load_directory (project, ANJUTA_PROJECT_NODE (project), NULL);