core: add option whitespace in command /debug (closes #947)

New options are added to configure the chars displayed for spaces and
tabulations:

- weechat.look.whitespace_char: char for spaces
- weechat.look.tab_whitespace_char: first char for tabulations

src/core/core-command.c

@@ -2291,6 +2291,13 @@ COMMAND_CALLBACK(debug)
         return WEECHAT_RC_OK;
     }
 
+    if (string_strcmp (argv[1], "whitespace") == 0)
+    {
+        gui_chat_whitespace_mode ^= 1;
+        gui_window_ask_refresh (1);
+        return WEECHAT_RC_OK;
+    }
+
     COMMAND_ERROR;
 }
 
@@ -8620,7 +8627,8 @@ command_init ()
            " || mouse|cursor [verbose]"
            " || hdata [free]"
            " || time <command>"
-           " || unicode <string>"),
+           " || unicode <string>"
+           " || whitespace"),
         CMD_ARGS_DESC(
             N_("raw[list]: list plugins with debug levels"),
             N_("raw[set]: set debug level for plugin"),
@@ -8662,6 +8670,9 @@ command_init ()
                "the current buffer"),
             N_("raw[unicode]: display information about string and unicode chars "
                "(evaluated, see /help eval)"),
+            N_("raw[whitespace]: toggle whitespace mode: make spaces and tabulations "
+               "visible in buffers and bars (see options weechat.look.whitespace_char "
+               "and weechat.look.tab_whitespace_char)"),
             "",
             N_("Examples:"),
             AI("  /debug set irc 1"),
@@ -8690,7 +8701,8 @@ command_init ()
         " || url"
         " || windows"
         " || time %(commands:/)"
-        " || unicode",
+        " || unicode"
+        " || whitespace",
         &command_debug, NULL, NULL);
     hook_command (
         NULL, "eval",

src/core/core-config.c

@@ -217,8 +217,10 @@ struct t_config_option *config_look_scroll_page_percent = NULL;
 struct t_config_option *config_look_search_text_not_found_alert = NULL;
 struct t_config_option *config_look_separator_horizontal = NULL;
 struct t_config_option *config_look_separator_vertical = NULL;
+struct t_config_option *config_look_tab_whitespace_char = NULL;
 struct t_config_option *config_look_tab_width = NULL;
 struct t_config_option *config_look_time_format = NULL;
+struct t_config_option *config_look_whitespace_char = NULL;
 struct t_config_option *config_look_window_auto_zoom = NULL;
 struct t_config_option *config_look_window_separator_horizontal = NULL;
 struct t_config_option *config_look_window_separator_vertical = NULL;
@@ -361,6 +363,7 @@ int config_num_highlight_tags = 0;
 char **config_plugin_extensions = NULL;
 int config_num_plugin_extensions = 0;
 char config_tab_spaces[TAB_MAX_WIDTH + 1];
+char config_tab_spaces_whitespace[(TAB_MAX_WIDTH * 4) + 1];
 struct t_config_look_word_char_item *config_word_chars_highlight = NULL;
 int config_word_chars_highlight_count = 0;
 struct t_config_look_word_char_item *config_word_chars_input = NULL;
@@ -1311,20 +1314,54 @@ config_check_separator (const void *pointer, void *data,
 }
 
 /*
- * Callback for changes on option "weechat.look.tab_width".
+ * Checks options "weechat.look.whitespace_char" and
+ * "weechat.look.tab_whitespace_char".
  */
 
-void
-config_change_tab_width (const void *pointer, void *data,
-                         struct t_config_option *option)
+int
+config_check_whitespace_char (const void *pointer, void *data,
+                              struct t_config_option *option,
+                              const char *value)
 {
     /* make C compiler happy */
     (void) pointer;
     (void) data;
     (void) option;
 
-    memset (config_tab_spaces, ' ', CONFIG_INTEGER(config_look_tab_width));
-    config_tab_spaces[CONFIG_INTEGER(config_look_tab_width)] = '\0';
+    return (utf8_strlen_screen (value) == 1) ? 1 : 0;
+}
+
+/*
+ * Callback for changes on options "weechat.look.tab_width" and
+ * "weechat.look.tab_whitespace_char".
+ */
+
+void
+config_change_tab (const void *pointer, void *data,
+                   struct t_config_option *option)
+{
+    int tab_width, i;
+
+    /* make C compiler happy */
+    (void) pointer;
+    (void) data;
+    (void) option;
+
+    tab_width = CONFIG_INTEGER(config_look_tab_width);
+
+    /* build a string with spaces that replace Tab char */
+    memset (config_tab_spaces, ' ', tab_width);
+    config_tab_spaces[tab_width] = '\0';
+
+    /* replaces spaces in whitespace mode */
+    config_tab_spaces_whitespace[0] = '\0';
+    strcat (config_tab_spaces_whitespace,
+            CONFIG_STRING(config_look_tab_whitespace_char));
+    for (i = 1; i < tab_width; i++)
+    {
+        strcat (config_tab_spaces_whitespace,
+                CONFIG_STRING(config_look_whitespace_char));
+    }
 
     gui_window_ask_refresh (1);
 }
@@ -4336,13 +4373,24 @@ config_weechat_init_options ()
             &config_check_separator, NULL, NULL,
             &config_change_buffers, NULL, NULL,
             NULL, NULL, NULL);
+        config_look_tab_whitespace_char = config_file_new_option (
+            weechat_config_file, weechat_config_section_look,
+            "tab_whitespace_char", "string",
+            N_("first char to display for tabulations when whitespace mode is "
+               "enabled with command `/debug whitespace`; width on screen must "
+               "be exactly one char; subsequent chars are set by option "
+               "weechat.look.whitespace_char"),
+            NULL, 0, 0, "→", NULL, 0,
+            &config_check_whitespace_char, NULL, NULL,
+            &config_change_tab, NULL, NULL,
+            NULL, NULL, NULL);
         config_look_tab_width = config_file_new_option (
             weechat_config_file, weechat_config_section_look,
             "tab_width", "integer",
             N_("number of spaces used to display tabs in messages"),
             NULL, 1, TAB_MAX_WIDTH, "1", NULL, 0,
             NULL, NULL, NULL,
-            &config_change_tab_width, NULL, NULL,
+            &config_change_tab, NULL, NULL,
             NULL, NULL, NULL);
         config_look_time_format = config_file_new_option (
             weechat_config_file, weechat_config_section_look,
@@ -4351,6 +4399,16 @@ config_weechat_init_options ()
                "messages (see man strftime for date/time specifiers)"),
             NULL, 0, 0, "%a, %d %b %Y %T", NULL, 0,
             NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL);
+        config_look_whitespace_char = config_file_new_option (
+            weechat_config_file, weechat_config_section_look,
+            "whitespace_char", "string",
+            N_("char to display for spaces when whitespace mode is enabled with "
+               "command `/debug whitespace`; width on screen must be exactly "
+               "one char; see also option weechat.look.tab_whitespace_char"),
+            NULL, 0, 0, "·", NULL, 0,
+            &config_check_whitespace_char, NULL, NULL,
+            &config_change_buffers, NULL, NULL,
+            NULL, NULL, NULL);
         config_look_window_auto_zoom = config_file_new_option (
             weechat_config_file, weechat_config_section_look,
             "window_auto_zoom", "boolean",
@@ -5477,6 +5535,8 @@ config_weechat_init ()
     time_t seconds;
 
     snprintf (config_tab_spaces, sizeof (config_tab_spaces), " ");
+    snprintf (config_tab_spaces_whitespace, sizeof (config_tab_spaces_whitespace),
+              "\u2192");
 
     rc = config_weechat_init_options ();
 

src/core/core-config.h

@@ -273,8 +273,10 @@ extern struct t_config_option *config_look_scroll_page_percent;
 extern struct t_config_option *config_look_search_text_not_found_alert;
 extern struct t_config_option *config_look_separator_horizontal;
 extern struct t_config_option *config_look_separator_vertical;
+extern struct t_config_option *config_look_tab_whitespace_char;
 extern struct t_config_option *config_look_tab_width;
 extern struct t_config_option *config_look_time_format;
+extern struct t_config_option *config_look_whitespace_char;
 extern struct t_config_option *config_look_window_auto_zoom;
 extern struct t_config_option *config_look_window_separator_horizontal;
 extern struct t_config_option *config_look_window_separator_vertical;
@@ -397,6 +399,7 @@ extern int config_num_highlight_tags;
 extern char **config_plugin_extensions;
 extern int config_num_plugin_extensions;
 extern char config_tab_spaces[];
+extern char config_tab_spaces_whitespace[];
 extern struct t_config_look_word_char_item *config_word_chars_highlight;
 extern int config_word_chars_highlight_count;
 extern struct t_config_look_word_char_item *config_word_chars_input;

src/gui/curses/gui-curses-bar-window.c

@@ -351,7 +351,14 @@ gui_bar_window_print_string (struct t_gui_bar_window *bar_window,
                 if (utf_char[0] == '\t')
                 {
                     /* expand tabulation with spaces */
-                    ptr_char = config_tab_spaces;
+                    ptr_char = (gui_chat_whitespace_mode) ?
+                        config_tab_spaces_whitespace : config_tab_spaces;
+                }
+                else if ((utf_char[0] == ' ') && gui_chat_whitespace_mode)
+                {
+                    /* replace space in whitespace mode */
+                    snprintf (utf_char, sizeof (utf_char),
+                              "%s", CONFIG_STRING(config_look_whitespace_char));
                 }
                 else if (((unsigned char)utf_char[0]) < 32)
                 {

src/gui/curses/gui-curses-chat.c

@@ -411,7 +411,14 @@ gui_chat_display_word_raw (struct t_gui_window *window, struct t_gui_line *line,
             if (utf_char[0] == '\t')
             {
                 /* expand tabulation with spaces */
-                ptr_char = config_tab_spaces;
+                ptr_char = (gui_chat_whitespace_mode) ?
+                    config_tab_spaces_whitespace : config_tab_spaces;
+            }
+            else if ((utf_char[0] == ' ') && gui_chat_whitespace_mode)
+            {
+                /* replace space in whitespace mode */
+                snprintf (utf_char, sizeof (utf_char),
+                          "%s", CONFIG_STRING(config_look_whitespace_char));
             }
             else if (((unsigned char)utf_char[0]) < 32)
             {

src/gui/gui-chat.c

@@ -60,6 +60,7 @@ struct t_gui_buffer *gui_chat_mute_buffer = NULL; /* mute buffer            */
 int gui_chat_display_tags = 0;                  /* display tags?            */
 char **gui_chat_lines_waiting_buffer = NULL;    /* lines waiting for core   */
                                                 /* buffer                   */
+int gui_chat_whitespace_mode = 0;               /* make whitespaces visible */
 
 /* command /pipe */
 int gui_chat_pipe = 0;                          /* pipe enabled             */

src/gui/gui-chat.h

@@ -80,6 +80,7 @@ extern char gui_chat_prefix_empty[];
 extern int gui_chat_time_length;
 extern int gui_chat_mute;
 extern struct t_gui_buffer *gui_chat_mute_buffer;
+extern int gui_chat_whitespace_mode;
 extern int gui_chat_pipe;
 extern char *gui_chat_pipe_command;
 extern struct t_gui_buffer *gui_chat_pipe_buffer;