[vte] widget: Improve set_encoding API

[Christian Persch <chpe src gnome org>]

commit 55364d008339077e765f8328ad86ac0b1fc40107
Author: Christian Persch <chpe gnome org>
Date:   Fri Aug 15 13:30:09 2014 +0200

    widget: Improve set_encoding API
    
    Since opening the converter can fail, make this return a gboolean and a GError.
    And change the meaning of NULL as @codeset from 'current locale' to 'UTF-8'.

 src/app.vala      |    9 +++++++--
 src/vte.c         |   53 +++++++++++++++++++++++++++++++----------------------
 src/vteapp.c      |    4 +++-
 src/vteseq.c      |    4 ++--
 src/vteterminal.h |    5 +++--
 5 files changed, 46 insertions(+), 29 deletions(-)
---
diff --git a/src/app.vala b/src/app.vala
index 2f03706..77ea78c 100644
--- a/src/app.vala
+++ b/src/app.vala
@@ -106,8 +106,13 @@ class Window : Gtk.ApplicationWindow
     if (App.Options.no_double_buffer)
       terminal.set_double_buffered(true);
 
-    if (App.Options.encoding != null)
-      terminal.set_encoding(App.Options.encoding);
+    if (App.Options.encoding != null) {
+      try {
+        terminal.set_encoding(App.Options.encoding);
+      } catch (Error e) {
+        printerr("Failed to set encoding: %s\n", e.message);
+      }
+    }
 
     terminal.set_audible_bell(App.Options.audible);
     terminal.set_cjk_ambiguous_width(App.Options.get_cjk_ambiguous_width());
diff --git a/src/vte.c b/src/vte.c
index bb67e9f..67b4ba7 100644
--- a/src/vte.c
+++ b/src/vte.c
@@ -1959,15 +1959,20 @@ _vte_terminal_setup_utf8 (VteTerminal *terminal)
 /**
  * vte_terminal_set_encoding:
  * @terminal: a #VteTerminal
- * @codeset: (allow-none): a valid #GIConv target, or %NULL to use the default encoding
+ * @codeset: (allow-none): a valid #GIConv target, or %NULL to use UTF-8
+ * @error: (allow-none): return location for a #GError, or %NULL
  *
  * Changes the encoding the terminal will expect data from the child to
  * be encoded with.  For certain terminal types, applications executing in the
- * terminal can change the encoding.  The default encoding is defined by the
- * application's locale settings.
+ * terminal can change the encoding. If @codeset is %NULL, it uses "UTF-8".
+ *
+ * Returns: %TRUE if the encoding could be changed to the specified one,
+ *  or %FALSE with @error set to %G_CONVERT_ERROR_NO_CONVERSION.
  */
-void
-vte_terminal_set_encoding(VteTerminal *terminal, const char *codeset)
+gboolean
+vte_terminal_set_encoding(VteTerminal *terminal,
+                          const char *codeset,
+                          GError **error)
 {
         VteTerminalPrivate *pvt;
         GObject *object;
@@ -1976,30 +1981,32 @@ vte_terminal_set_encoding(VteTerminal *terminal, const char *codeset)
        char *obuf1, *obuf2;
        gsize bytes_written;
 
-       g_return_if_fail(VTE_IS_TERMINAL(terminal));
+       g_return_val_if_fail(VTE_IS_TERMINAL(terminal), FALSE);
+        g_return_val_if_fail(error == NULL || *error == NULL, FALSE);
 
         object = G_OBJECT(terminal);
         pvt = terminal->pvt;
 
        old_codeset = pvt->encoding;
        if (codeset == NULL) {
-               g_get_charset(&codeset);
+                codeset = "UTF-8";
        }
-       if ((old_codeset != NULL) && (strcmp(codeset, old_codeset) == 0)) {
+       if ((old_codeset != NULL) && g_str_equal(codeset, old_codeset)) {
                /* Nothing to do! */
-               return;
+               return TRUE;
        }
 
-        g_object_freeze_notify(object);
-
        /* Open new conversions. */
        conv = _vte_conv_open(codeset, "UTF-8");
        if (conv == VTE_INVALID_CONV) {
-               g_warning(_("Unable to convert characters from %s to %s."),
-                         "UTF-8", codeset);
-               /* fallback to no conversion */
-               conv = _vte_conv_open(codeset = "UTF-8", "UTF-8");
-       }
+               g_set_error(error, G_CONVERT_ERROR, G_CONVERT_ERROR_NO_CONVERSION,
+                            _("Unable to convert characters from %s to %s."),
+                            "UTF-8", codeset);
+                return FALSE;
+        }
+
+        g_object_freeze_notify(object);
+
        if (terminal->pvt->outgoing_conv != VTE_INVALID_CONV) {
                _vte_conv_close(terminal->pvt->outgoing_conv);
        }
@@ -2048,6 +2055,8 @@ vte_terminal_set_encoding(VteTerminal *terminal, const char *codeset)
        vte_terminal_emit_encoding_changed(terminal);
 
         g_object_thaw_notify(object);
+
+        return TRUE;
 }
 
 /**
@@ -7990,7 +7999,7 @@ _vte_terminal_inline_error_message(VteTerminal *terminal, const char *format, ..
 static void
 _vte_terminal_codeset_changed_cb(struct _vte_iso2022_state *state, gpointer p)
 {
-       vte_terminal_set_encoding(p, _vte_iso2022_state_get_codeset(state));
+       vte_terminal_set_encoding(p, _vte_iso2022_state_get_codeset(state), NULL);
 }
 
 /* Initialize the terminal widget after the base widget stuff is initialized.
@@ -8065,8 +8074,8 @@ vte_terminal_init(VteTerminal *terminal)
        pvt->outgoing = _vte_byte_array_new();
        pvt->outgoing_conv = VTE_INVALID_CONV;
        pvt->conv_buffer = _vte_byte_array_new();
-       vte_terminal_set_encoding(terminal, NULL);
-       g_assert(terminal->pvt->encoding != NULL);
+       vte_terminal_set_encoding(terminal, NULL /* UTF-8 */, NULL);
+       g_assert_cmpstr(terminal->pvt->encoding, ==, "UTF-8");
 
         /* Set up the emulation. */
        pvt->keypad_mode = VTE_KEYMODE_NORMAL;
@@ -10688,7 +10697,7 @@ vte_terminal_set_property (GObject *object,
                         vte_terminal_set_delete_binding (terminal, g_value_get_enum (value));
                         break;
                 case PROP_ENCODING:
-                        vte_terminal_set_encoding (terminal, g_value_get_string (value));
+                        vte_terminal_set_encoding (terminal, g_value_get_string (value), NULL);
                         break;
                 case PROP_FONT_DESC:
                         vte_terminal_set_font (terminal, g_value_get_boxed (value));
@@ -12467,8 +12476,8 @@ vte_terminal_reset(VteTerminal *terminal,
         /* For some reason, xterm doesn't reset alternateScroll, but we do. */
         pvt->alternate_screen_scroll = TRUE;
        /* Reset the encoding. */
-       vte_terminal_set_encoding(terminal, NULL);
-       g_assert(pvt->encoding != NULL);
+       vte_terminal_set_encoding(terminal, NULL /* UTF-8 */, NULL);
+       g_assert_cmpstr(pvt->encoding, ==, "UTF-8");
        /* Reset selection. */
        vte_terminal_deselect_all(terminal);
        pvt->has_selection = FALSE;
diff --git a/src/vteapp.c b/src/vteapp.c
index 0883b60..31536a9 100644
--- a/src/vteapp.c
+++ b/src/vteapp.c
@@ -944,7 +944,9 @@ main(int argc, char **argv)
        }
 
         if (encoding != NULL) {
-                vte_terminal_set_encoding(terminal, encoding);
+                if (!vte_terminal_set_encoding(terminal, encoding, &error)) {
+                        g_printerr("Failed to set encoding: %s\n", error->message);
+                }
                 g_free(encoding);
         }
         if (cjk_ambiguous_width != NULL) {
diff --git a/src/vteseq.c b/src/vteseq.c
index 2120960..c354cfc 100644
--- a/src/vteseq.c
+++ b/src/vteseq.c
@@ -2598,13 +2598,13 @@ vte_sequence_handler_default_character_set (VteTerminal *terminal, GValueArray *
 {
        G_CONST_RETURN char *locale_encoding;
        g_get_charset(&locale_encoding);
-       vte_terminal_set_encoding(terminal, locale_encoding);
+       vte_terminal_set_encoding(terminal, locale_encoding, NULL);
 }
 
 static void
 vte_sequence_handler_utf_8_character_set (VteTerminal *terminal, GValueArray *params)
 {
-       vte_terminal_set_encoding(terminal, "UTF-8");
+       vte_terminal_set_encoding(terminal, NULL /* UTF-8 */, NULL);
 }
 
 /* Device status reports. The possible reports are the cursor position and
diff --git a/src/vteterminal.h b/src/vteterminal.h
index dc479b5..1e9fe90 100644
--- a/src/vteterminal.h
+++ b/src/vteterminal.h
@@ -323,8 +323,9 @@ gboolean  vte_terminal_search_find_next       (VteTerminal *terminal) _VTE_GNUC_
 
 
 /* Set the character encoding.  Most of the time you won't need this. */
-void vte_terminal_set_encoding(VteTerminal *terminal,
-                               const char *codeset) _VTE_GNUC_NONNULL(1);
+gboolean vte_terminal_set_encoding(VteTerminal *terminal,
+                                   const char *codeset,
+                                   GError **error) _VTE_GNUC_NONNULL(1);
 const char *vte_terminal_get_encoding(VteTerminal *terminal) _VTE_GNUC_NONNULL(1);
 
 /* CJK compatibility setting */