[evolution] e_display_help: Call Yelp directly to display help

[Milan Crha <mcrha src gnome org>]

commit e6b0574417b1ded9b9057b4a2725dda56df72bec
Author: Milan Crha <mcrha redhat com>
Date:   Mon Feb 28 09:47:54 2022 +0100

    e_display_help: Call Yelp directly to display help
    
    Using a "help:" scheme can misbehave when there's installed a different
    scheme handler application, which doesn't open the Yelp files properly.
    One such application is KHelpCenter.
    
    Reported downstream as:
    https://bugzilla.redhat.com/show_bug.cgi?id=2057454

 src/e-util/e-misc-utils.c | 58 +++++++++++++++++++++++++++++++++++++++++------
 1 file changed, 51 insertions(+), 7 deletions(-)
---
diff --git a/src/e-util/e-misc-utils.c b/src/e-util/e-misc-utils.c
index 9dc738f431..f5b7d76758 100644
--- a/src/e-util/e-misc-utils.c
+++ b/src/e-util/e-misc-utils.c
@@ -288,7 +288,7 @@ e_show_uri (GtkWindow *parent,
 }
 
 static gboolean
-e_misc_utils_is_help_package_installed (void)
+e_misc_utils_is_help_package_installed (GAppInfo **out_yelp_info)
 {
        gboolean is_installed;
        gchar *path;
@@ -302,13 +302,29 @@ e_misc_utils_is_help_package_installed (void)
        g_free (path);
 
        if (is_installed) {
-               GAppInfo *help_handler;
+               GAppInfo *yelp_info = NULL;
+               GList *app_infos, *link;
 
-               help_handler = g_app_info_get_default_for_uri_scheme ("help");
+               app_infos = g_app_info_get_all_for_type ("x-scheme-handler/help");
 
-               is_installed = help_handler && g_app_info_get_commandline (help_handler);
+               for (link = app_infos; link; link = g_list_next (link)) {
+                       GAppInfo *app_info = link->data;
+                       const gchar *executable;
 
-               g_clear_object (&help_handler);
+                       executable = g_app_info_get_executable (app_info);
+
+                       if (executable && camel_strstrcase (executable, "yelp")) {
+                               yelp_info = app_info;
+                               break;
+                       }
+               }
+
+               is_installed = yelp_info && g_app_info_get_commandline (yelp_info);
+
+               if (is_installed)
+                       *out_yelp_info = g_object_ref (yelp_info);
+
+               g_list_free_full (app_infos, g_object_unref);
        }
 
        return is_installed;
@@ -328,13 +344,14 @@ void
 e_display_help (GtkWindow *parent,
                 const gchar *link_id)
 {
+       GAppInfo *yelp_info = NULL;
        GString *uri;
        GtkWidget *dialog;
        GdkScreen *screen = NULL;
        GError *error = NULL;
        guint32 timestamp;
 
-       if (e_misc_utils_is_help_package_installed ()) {
+       if (e_misc_utils_is_help_package_installed (&yelp_info)) {
                uri = g_string_new ("help:" PACKAGE);
        } else {
                uri = g_string_new ("https://help.gnome.org/users/"; PACKAGE "/");
@@ -353,8 +370,34 @@ e_display_help (GtkWindow *parent,
                g_string_append (uri, link_id);
        }
 
-       if (gtk_show_uri (screen, uri->str, timestamp, &error))
+       if (yelp_info) {
+               GAppLaunchContext *context = NULL;
+               GList *uris;
+               gboolean success;
+
+               uris = g_list_prepend (NULL, uri->str);
+
+               if (parent && gtk_widget_get_screen (GTK_WIDGET (parent))) {
+                       GdkAppLaunchContext *gdk_context;
+                       GdkScreen *screen;
+
+                       screen = gtk_widget_get_screen (GTK_WIDGET (parent));
+                       gdk_context = gdk_display_get_app_launch_context (gdk_screen_get_display (screen));
+
+                       if (gdk_context)
+                               context = G_APP_LAUNCH_CONTEXT (gdk_context);
+               }
+
+               success = g_app_info_launch_uris (yelp_info, uris, context, &error);
+
+               g_list_free (uris);
+               g_clear_object (&context);
+
+               if (success)
+                       goto exit;
+       } else if (gtk_show_uri (screen, uri->str, timestamp, &error)) {
                goto exit;
+       }
 
        dialog = gtk_message_dialog_new_with_markup (
                parent, GTK_DIALOG_DESTROY_WITH_PARENT,
@@ -372,6 +415,7 @@ e_display_help (GtkWindow *parent,
 
 exit:
        g_string_free (uri, TRUE);
+       g_clear_object (&yelp_info);
 }
 
 /**