[vte] widget: Deprecate the attributes out-param for vte_terminal_get_text

[Christian Persch <chpe src gnome org>]

commit ab85f122db965d56ace54d01fd391300795ee0c0
Author: Christian Persch <chpe src gnome org>
Date:   Tue Feb 8 20:30:31 2022 +0100

    widget: Deprecate the attributes out-param for vte_terminal_get_text
    
    Part of the future fix for issue #2504.

 src/vtegtk.cc | 38 +++++++++++++++++++++++++++++++++-----
 1 file changed, 33 insertions(+), 5 deletions(-)
---
diff --git a/src/vtegtk.cc b/src/vtegtk.cc
index 1ec20def..38edab4d 100644
--- a/src/vtegtk.cc
+++ b/src/vtegtk.cc
@@ -4077,7 +4077,8 @@ catch (...)
  */
 
 static void
-warn_if_callback(VteSelectionFunc func) noexcept
+warn_if_callback(VteSelectionFunc func,
+                 char const* caller = __builtin_FUNCTION()) noexcept
 {
         if (!func)
                 return;
@@ -4088,7 +4089,23 @@ warn_if_callback(VteSelectionFunc func) noexcept
                 return;
         warned = TRUE;
 #endif
-        g_warning ("VteSelectionFunc callback ignored.\n");
+        g_warning ("%s: VteSelectionFunc callback ignored.\n", caller);
+}
+
+static void
+warn_if_attributes(void* array,
+                   char const* caller = __builtin_FUNCTION()) noexcept
+{
+        if (!array)
+                return;
+
+#ifndef VTE_DEBUG
+        static gboolean warned = FALSE;
+        if (warned)
+                return;
+        warned = TRUE;
+#endif
+        g_warning ("%s: Passing a GArray to retrieve attributes is deprecated. In a future version, passing 
non-NULL as attributes array will make the function return NULL.\n", caller);
 }
 
 /**
@@ -4096,7 +4113,7 @@ warn_if_callback(VteSelectionFunc func) noexcept
  * @terminal: a #VteTerminal
  * @is_selected: (scope call) (allow-none): a #VteSelectionFunc callback
  * @user_data: (closure): user data to be passed to the callback
- * @attributes: (nullable) (out caller-allocates) (transfer full) (array) (element-type Vte.CharAttributes): 
location for storing text attributes
+ * @attributes: (nullable) (out caller-allocates) (transfer full) (array) (element-type Vte.CharAttributes): 
location for storing text attributes. Deprecated: 0.68: Always pass %NULL here.
  *
  * Extracts a view of the visible part of the terminal.  If @is_selected is not
  * %NULL, characters will only be read if @is_selected returns %TRUE after being
@@ -4107,6 +4124,9 @@ warn_if_callback(VteSelectionFunc func) noexcept
  * This method is unaware of BiDi. The columns returned in @attributes are
  * logical columns.
  *
+ * Note: since 0.68, passing a non-%NULL @array parameter is deprecated. Starting with
+ * 0.70, passing a non-%NULL @array parameter will make this function itself return %NULL.
+ *
  * Returns: (transfer full) (nullable): a newly allocated text string, or %NULL.
  */
 char *
@@ -4118,6 +4138,7 @@ try
 {
        g_return_val_if_fail(VTE_IS_TERMINAL(terminal), NULL);
         warn_if_callback(is_selected);
+        warn_if_attributes(attributes);
         auto text = IMPL(terminal)->get_text_displayed(true /* wrap */,
                                                        attributes);
         if (text == nullptr)
@@ -4135,7 +4156,7 @@ catch (...)
  * @terminal: a #VteTerminal
  * @is_selected: (scope call) (allow-none): a #VteSelectionFunc callback
  * @user_data: (closure): user data to be passed to the callback
- * @attributes: (out caller-allocates) (transfer full) (array) (element-type Vte.CharAttributes): location 
for storing text attributes
+ * @attributes: (out caller-allocates) (transfer full) (array) (element-type Vte.CharAttributes): location 
for storing text attributes. Deprecated: 0.68: Always pass %NULL here.
  *
  * Extracts a view of the visible part of the terminal.  If @is_selected is not
  * %NULL, characters will only be read if @is_selected returns %TRUE after being
@@ -4146,6 +4167,9 @@ catch (...)
  * This method is unaware of BiDi. The columns returned in @attributes are
  * logical columns.
  *
+ * Note: since 0.68, passing a non-%NULL @array parameter is deprecated. Starting with
+ * 0.70, passing a non-%NULL @array parameter will make this function itself return %NULL.
+ *
  * Returns: (transfer full): a newly allocated text string, or %NULL.
  *
  * Deprecated: 0.56: Use vte_terminal_get_text() instead.
@@ -4168,7 +4192,7 @@ vte_terminal_get_text_include_trailing_spaces(VteTerminal *terminal,
  * @end_col: last column to search for data
  * @is_selected: (scope call) (allow-none): a #VteSelectionFunc callback
  * @user_data: (closure): user data to be passed to the callback
- * @attributes: (nullable) (out caller-allocates) (transfer full) (array) (element-type Vte.CharAttributes): 
location for storing text attributes
+ * @attributes: (nullable) (out caller-allocates) (transfer full) (array) (element-type Vte.CharAttributes): 
location for storing text attributes. Deprecated: 0.68: Always pass %NULL here.
  *
  * Extracts a view of the visible part of the terminal.  If @is_selected is not
  * %NULL, characters will only be read if @is_selected returns %TRUE after being
@@ -4181,6 +4205,9 @@ vte_terminal_get_text_include_trailing_spaces(VteTerminal *terminal,
  * This method is unaware of BiDi. The columns passed in @start_col and @end_row,
  * and returned in @attributes are logical columns.
  *
+ * Note: since 0.68, passing a non-%NULL @array parameter is deprecated. Starting with
+ * 0.70, passing a non-%NULL @array parameter will make this function itself return %NULL.
+ *
  * Returns: (transfer full) (nullable): a newly allocated text string, or %NULL.
  */
 char *
@@ -4196,6 +4223,7 @@ try
 {
        g_return_val_if_fail(VTE_IS_TERMINAL(terminal), NULL);
         warn_if_callback(is_selected);
+        warn_if_attributes(attributes);
         auto text = IMPL(terminal)->get_text(start_row, start_col,
                                              end_row, end_col,
                                              false /* block */,