[tepl] Utils: add file_query_exists_async()/finish()

[Sébastien Wilmet <swilmet src gnome org>]

commit 3786c76cb942f76b14a9f1245068536cd7c640d5
Author: Sébastien Wilmet <swilmet gnome org>
Date:   Thu Apr 16 12:53:49 2020 +0200

    Utils: add file_query_exists_async()/finish()
    
    Copied from gnome-latex.

 docs/reference/tepl-sections.txt |  2 ++
 tepl/tepl-utils.c                | 56 ++++++++++++++++++++++++++++++++++++++++
 tepl/tepl-utils.h                |  8 ++++++
 3 files changed, 66 insertions(+)
---
diff --git a/docs/reference/tepl-sections.txt b/docs/reference/tepl-sections.txt
index 9321509..ce4ccd5 100644
--- a/docs/reference/tepl-sections.txt
+++ b/docs/reference/tepl-sections.txt
@@ -416,6 +416,8 @@ tepl_utils_get_file_shortname
 tepl_utils_replace_home_dir_with_tilde
 tepl_utils_decode_uri
 tepl_utils_create_parent_directories
+tepl_utils_file_query_exists_async
+tepl_utils_file_query_exists_finish
 tepl_utils_show_warning_dialog
 </SECTION>
 
diff --git a/tepl/tepl-utils.c b/tepl/tepl-utils.c
index 097c954..0aa5bfb 100644
--- a/tepl/tepl-utils.c
+++ b/tepl/tepl-utils.c
@@ -614,6 +614,62 @@ tepl_utils_create_parent_directories (GFile         *file,
        return TRUE;
 }
 
+/**
+ * tepl_utils_file_query_exists_async:
+ * @file: a #GFile.
+ * @cancellable: a #GCancellable.
+ * @callback: the callback to call when the operation is finished.
+ * @user_data: the data to pass to the callback function.
+ *
+ * The asynchronous version of g_file_query_exists(). When the operation is
+ * finished, @callback will be called. You can then call
+ * tepl_utils_file_query_exists_finish() to get the result of the operation.
+ *
+ * Since: 5.0
+ */
+void
+tepl_utils_file_query_exists_async (GFile               *file,
+                                   GCancellable        *cancellable,
+                                   GAsyncReadyCallback  callback,
+                                   gpointer             user_data)
+{
+       g_file_query_info_async (file,
+                                G_FILE_ATTRIBUTE_STANDARD_TYPE,
+                                G_FILE_QUERY_INFO_NONE,
+                                G_PRIORITY_DEFAULT,
+                                cancellable,
+                                callback,
+                                user_data);
+}
+
+/**
+ * tepl_utils_file_query_exists_finish:
+ * @file: a #GFile.
+ * @result: a #GAsyncResult.
+ *
+ * Finishes the operation started with tepl_utils_file_query_exists_async().
+ * There is no output #GError parameter, so you should check if the operation
+ * has been cancelled (in which case %FALSE will be returned).
+ *
+ * Returns: %TRUE if the file exists and the operation hasn't been cancelled,
+ * %FALSE otherwise.
+ * Since: 5.0
+ */
+gboolean
+tepl_utils_file_query_exists_finish (GFile        *file,
+                                    GAsyncResult *result)
+{
+       GFileInfo *info = g_file_query_info_finish (file, result, NULL);
+
+       if (info != NULL)
+       {
+               g_object_unref (info);
+               return TRUE;
+       }
+
+       return FALSE;
+}
+
 GtkWidget *
 _tepl_utils_create_close_button (void)
 {
diff --git a/tepl/tepl-utils.h b/tepl/tepl-utils.h
index 2c89f83..b43877b 100644
--- a/tepl/tepl-utils.h
+++ b/tepl/tepl-utils.h
@@ -64,6 +64,14 @@ gboolean     tepl_utils_create_parent_directories            (GFile         *file,
                                                                 GCancellable  *cancellable,
                                                                 GError       **error);
 
+void           tepl_utils_file_query_exists_async              (GFile               *file,
+                                                                GCancellable        *cancellable,
+                                                                GAsyncReadyCallback  callback,
+                                                                gpointer             user_data);
+
+gboolean       tepl_utils_file_query_exists_finish             (GFile        *file,
+                                                                GAsyncResult *result);
+
 /* Widget utilities */
 
 G_GNUC_INTERNAL