Move title_format from window to container.

This patch moves the title_format information from windows to containers.
Furthermore, it allows correctly setting it on window-less containers and
displays the title accordingly for split containers.

We now also dump and read title_format in GET_TREE / during restarts.

fixes #2120

docs/userguide

@@ -2215,7 +2215,10 @@ https://developer.gnome.org/pango/stable/PangoMarkupFormat.html[Pango markup]
 and the following placeholders which will be replaced:
 
 +%title+::
-    The X11 window title (_NET_WM_NAME or WM_NAME as fallback).
+    For normal windows, this is the X11 window title (_NET_WM_NAME or WM_NAME
+    as fallback). When used on containers without a window (e.g., a split
+    container inside a tabbed/stacked layout), this will be the tree
+    representation of the container (e.g., "H[xterm xterm]").
 +%class+::
     The X11 window class (second part of WM_CLASS). This corresponds to the
     +class+ criterion, see <<command_criteria>>.

i3bar/include/util.h

@@ -15,7 +15,7 @@
 #undef MIN
 #define MIN(x, y) ((x) < (y) ? (x) : (y))
 
-#define STARTS_WITH(string, len, needle) ((len >= strlen(needle)) && strncasecmp(string, needle, strlen(needle)) == 0)
+#define STARTS_WITH(string, len, needle) (((len) >= strlen((needle))) && strncasecmp((string), (needle), strlen((needle))) == 0)
 
 /* Securely free p */
 #define FREE(p)          \

include/con.h

@@ -433,3 +433,9 @@ char *con_get_tree_representation(Con *con);
  *
  */
 void con_force_split_parents_redraw(Con *con);
+
+/**
+ * Returns the window title considering the current title format.
+ *
+ */
+i3String *con_parse_title_format(Con *con);

include/data.h

@@ -376,8 +376,6 @@ struct Window {
 
     /** The name of the window. */
     i3String *name;
-    /** The format with which the window's name should be displayed. */
-    char *title_format;
 
     /** The WM_WINDOW_ROLE of this window (for example, the pidgin buddy window
      * sets "buddy list"). Useful to match specific windows in assignments or
@@ -588,6 +586,9 @@ struct Con {
 
     char *name;
 
+    /** The format with which the window's name should be displayed. */
+    char *title_format;
+
     /* a sticky-group is an identifier which bundles several containers to a
      * group. The contents are shared between all of them, that is they are
      * displayed on whichever of the containers is currently visible */

include/libi3.h

@@ -504,6 +504,20 @@ char *get_config_path(const char *override_configpath, bool use_system_paths);
 int mkdirp(const char *path, mode_t mode);
 #endif
 
+/** Helper structure for usage in format_placeholders(). */
+typedef struct placeholder_t {
+    /* The placeholder to be replaced, e.g., "%title". */
+    char *name;
+    /* The value this placeholder should be replaced with. */
+    char *value;
+} placeholder_t;
+
+/**
+ * Replaces occurences of the defined placeholders in the format string.
+ *
+ */
+char *format_placeholders(char *format, placeholder_t *placeholders, int num);
+
 #ifdef CAIRO_SUPPORT
 /* We need to flush cairo surfaces twice to avoid an assertion bug. See #1989
  * and https://bugs.freedesktop.org/show_bug.cgi?id=92455. */

include/util.h

@@ -20,7 +20,7 @@
         if (pointer == NULL)       \
             die(__VA_ARGS__);      \
     }
-#define STARTS_WITH(string, needle) (strncasecmp(string, needle, strlen(needle)) == 0)
+#define STARTS_WITH(string, needle) (strncasecmp((string), (needle), strlen((needle))) == 0)
 #define CIRCLEQ_NEXT_OR_NULL(head, elm, field) (CIRCLEQ_NEXT(elm, field) != CIRCLEQ_END(head) ? CIRCLEQ_NEXT(elm, field) : NULL)
 #define CIRCLEQ_PREV_OR_NULL(head, elm, field) (CIRCLEQ_PREV(elm, field) != CIRCLEQ_END(head) ? CIRCLEQ_PREV(elm, field) : NULL)
 #define FOR_TABLE(workspace)                             \

include/window.h

@@ -81,10 +81,3 @@ void window_update_hints(i3Window *win, xcb_get_property_reply_t *prop, bool *ur
  *
  */
 void window_update_motif_hints(i3Window *win, xcb_get_property_reply_t *prop, border_style_t *motif_border_style);
-
-/**
- * Returns the window title considering the current title format.
- * If no format is set, this will simply return the window's name.
- *
- */
-i3String *window_parse_title_format(i3Window *win);

libi3/format_placeholders.c

@@ -0,0 +1,67 @@
+/*
+ * vim:ts=4:sw=4:expandtab
+ *
+ * i3 - an improved dynamic tiling window manager
+ * © 2009 Michael Stapelberg and contributors (see also: LICENSE)
+ *
+ */
+#include <stdlib.h>
+#include <stdint.h>
+#include <string.h>
+
+#include "libi3.h"
+
+#ifndef STARTS_WITH
+#define STARTS_WITH(string, needle) (strncasecmp((string), (needle), strlen((needle))) == 0)
+#endif
+
+/*
+ * Replaces occurences of the defined placeholders in the format string.
+ *
+ */
+char *format_placeholders(char *format, placeholder_t *placeholders, int num) {
+    if (format == NULL)
+        return NULL;
+
+    /* We have to first iterate over the string to see how much buffer space
+     * we need to allocate. */
+    int buffer_len = strlen(format) + 1;
+    for (char *walk = format; *walk != '\0'; walk++) {
+        for (int i = 0; i < num; i++) {
+            if (!STARTS_WITH(walk, placeholders[i].name))
+                continue;
+
+            buffer_len = buffer_len - strlen(placeholders[i].name) + strlen(placeholders[i].value);
+            walk += strlen(placeholders[i].name) - 1;
+            break;
+        }
+    }
+
+    /* Now we can parse the format string. */
+    char buffer[buffer_len];
+    char *outwalk = buffer;
+    for (char *walk = format; *walk != '\0'; walk++) {
+        if (*walk != '%') {
+            *(outwalk++) = *walk;
+            continue;
+        }
+
+        bool matched = false;
+        for (int i = 0; i < num; i++) {
+            if (!STARTS_WITH(walk, placeholders[i].name)) {
+                continue;
+            }
+
+            matched = true;
+            outwalk += sprintf(outwalk, "%s", placeholders[i].value);
+            walk += strlen(placeholders[i].name) - 1;
+            break;
+        }
+
+        if (!matched)
+            *(outwalk++) = *walk;
+    }
+
+    *outwalk = '\0';
+    return sstrdup(buffer);
+}

src/commands.c

@@ -1926,27 +1926,33 @@ void cmd_title_format(I3_CMD, const char *format) {
 
     owindow *current;
     TAILQ_FOREACH(current, &owindows, owindows) {
-        if (current->con->window == NULL)
-            continue;
-
         DLOG("setting title_format for %p / %s\n", current->con, current->con->name);
-        FREE(current->con->window->title_format);
+        FREE(current->con->title_format);
 
         /* If we only display the title without anything else, we can skip the parsing step,
          * so we remove the title format altogether. */
         if (strcasecmp(format, "%title") != 0) {
-            current->con->window->title_format = sstrdup(format);
+            current->con->title_format = sstrdup(format);
 
-            i3String *formatted_title = window_parse_title_format(current->con->window);
+            if (current->con->window != NULL) {
+                i3String *formatted_title = con_parse_title_format(current->con);
                 ewmh_update_visible_name(current->con->window->id, i3string_as_utf8(formatted_title));
                 I3STRING_FREE(formatted_title);
+            }
         } else {
+            if (current->con->window != NULL) {
                 /* We can remove _NET_WM_VISIBLE_NAME since we don't display a custom title. */
                 ewmh_update_visible_name(current->con->window->id, NULL);
             }
+        }
 
+        if (current->con->window != NULL) {
             /* Make sure the window title is redrawn immediately. */
             current->con->window->name_x_changed = true;
+        } else {
+            /* For windowless containers we also need to force the redrawing. */
+            FREE(current->con->deco_render_params);
+        }
     }
 
     cmd_output->needs_tree_render = true;

src/con.c

@@ -2000,3 +2000,47 @@ char *con_get_tree_representation(Con *con) {
 
     return complete_buf;
 }
+
+/*
+ * Returns the container's title considering the current title format.
+ *
+ */
+i3String *con_parse_title_format(Con *con) {
+    assert(con->title_format != NULL);
+
+    i3Window *win = con->window;
+
+    /* We need to ensure that we only escape the window title if pango
+     * is used by the current font. */
+    const bool pango_markup = font_is_pango();
+
+    char *title;
+    char *class;
+    char *instance;
+    if (win == NULL) {
+        title = pango_escape_markup(con_get_tree_representation(con));
+        class = sstrdup("i3-frame");
+        instance = sstrdup("i3-frame");
+    } else {
+        title = pango_escape_markup(sstrdup((win->name == NULL) ? "" : i3string_as_utf8(win->name)));
+        class = pango_escape_markup(sstrdup((win->class_class == NULL) ? "" : win->class_class));
+        instance = pango_escape_markup(sstrdup((win->class_instance == NULL) ? "" : win->class_instance));
+    }
+
+    placeholder_t placeholders[] = {
+        {.name = "%title", .value = title},
+        {.name = "%class", .value = class},
+        {.name = "%instance", .value = instance}};
+    const size_t num = sizeof(placeholders) / sizeof(placeholder_t);
+
+    char *formatted_str = format_placeholders(con->title_format, &placeholders[0], num);
+    i3String *formatted = i3string_from_utf8(formatted_str);
+    i3string_set_markup(formatted, pango_markup);
+    FREE(formatted_str);
+
+    for (size_t i = 0; i < num; i++) {
+        FREE(placeholders[i].value);
+    }
+
+    return formatted;
+}

src/ipc.c

@@ -372,6 +372,11 @@ void dump_node(yajl_gen gen, struct Con *con, bool inplace_restart) {
     else
         y(null);
 
+    if (con->title_format != NULL) {
+        ystr("title_format");
+        ystr(con->title_format);
+    }
+
     if (con->type == CT_WORKSPACE) {
         ystr("num");
         y(integer, con->num);

src/load_layout.c

@@ -264,6 +264,9 @@ static int json_string(void *ctx, const unsigned char *val, size_t len) {
         if (strcasecmp(last_key, "name") == 0) {
             json_node->name = scalloc(len + 1, 1);
             memcpy(json_node->name, val, len);
+        } else if (strcasecmp(last_key, "title_format") == 0) {
+            json_node->title_format = scalloc(len + 1, 1);
+            memcpy(json_node->title_format, val, len);
         } else if (strcasecmp(last_key, "sticky_group") == 0) {
             json_node->sticky_group = scalloc(len + 1, 1);
             memcpy(json_node->sticky_group, val, len);

src/util.c

@@ -343,6 +343,7 @@ char *pango_escape_markup(char *input) {
 
     char *escaped = g_markup_escape_text(input, -1);
     FREE(input);
+
     return escaped;
 }
 

src/window.c

@@ -67,8 +67,9 @@ void window_update_name(i3Window *win, xcb_get_property_reply_t *prop, bool befo
     win->name = i3string_from_utf8_with_length(xcb_get_property_value(prop),
                                                xcb_get_property_value_length(prop));
 
-    if (win->title_format != NULL) {
-        i3String *name = window_parse_title_format(win);
+    Con *con = con_by_window_id(win->id);
+    if (con != NULL && con->title_format != NULL) {
+        i3String *name = con_parse_title_format(con);
         ewmh_update_visible_name(win->id, i3string_as_utf8(name));
         I3STRING_FREE(name);
     }
@@ -110,8 +111,10 @@ void window_update_name_legacy(i3Window *win, xcb_get_property_reply_t *prop, bo
     i3string_free(win->name);
     win->name = i3string_from_utf8_with_length(xcb_get_property_value(prop),
                                                xcb_get_property_value_length(prop));
-    if (win->title_format != NULL) {
-        i3String *name = window_parse_title_format(win);
+
+    Con *con = con_by_window_id(win->id);
+    if (con != NULL && con->title_format != NULL) {
+        i3String *name = con_parse_title_format(con);
         ewmh_update_visible_name(win->id, i3string_as_utf8(name));
         I3STRING_FREE(name);
     }
@@ -340,77 +343,3 @@ void window_update_motif_hints(i3Window *win, xcb_get_property_reply_t *prop, bo
 #undef MWM_DECOR_BORDER
 #undef MWM_DECOR_TITLE
 }
-
-/*
- * Returns the window title considering the current title format.
- * If no format is set, this will simply return the window's name.
- *
- */
-i3String *window_parse_title_format(i3Window *win) {
-    char *format = win->title_format;
-    if (format == NULL)
-        return i3string_copy(win->name);
-
-    /* We initialize these lazily so we only escape them if really necessary. */
-    char *escaped_title = NULL;
-    char *escaped_class = NULL;
-    char *escaped_instance = NULL;
-
-    /* We have to first iterate over the string to see how much buffer space
-     * we need to allocate. */
-    int buffer_len = strlen(format) + 1;
-    for (char *walk = format; *walk != '\0'; walk++) {
-        if (STARTS_WITH(walk, "%title")) {
-            if (escaped_title == NULL)
-                escaped_title = pango_escape_markup(sstrdup((win->name == NULL) ? "" : i3string_as_utf8(win->name)));
-
-            buffer_len = buffer_len - strlen("%title") + strlen(escaped_title);
-            walk += strlen("%title") - 1;
-        } else if (STARTS_WITH(walk, "%class")) {
-            if (escaped_class == NULL)
-                escaped_class = pango_escape_markup(sstrdup((win->class_class == NULL) ? "" : win->class_class));
-
-            buffer_len = buffer_len - strlen("%class") + strlen(escaped_class);
-            walk += strlen("%class") - 1;
-        } else if (STARTS_WITH(walk, "%instance")) {
-            if (escaped_instance == NULL)
-                escaped_instance = pango_escape_markup(sstrdup((win->class_instance == NULL) ? "" : win->class_instance));
-
-            buffer_len = buffer_len - strlen("%instance") + strlen(escaped_instance);
-            walk += strlen("%instance") - 1;
-        }
-    }
-
-    /* Now we can parse the format string. */
-    char buffer[buffer_len];
-    char *outwalk = buffer;
-    for (char *walk = format; *walk != '\0'; walk++) {
-        if (*walk != '%') {
-            *(outwalk++) = *walk;
-            continue;
-        }
-
-        if (STARTS_WITH(walk + 1, "title")) {
-            outwalk += sprintf(outwalk, "%s", escaped_title);
-            walk += strlen("title");
-        } else if (STARTS_WITH(walk + 1, "class")) {
-            outwalk += sprintf(outwalk, "%s", escaped_class);
-            walk += strlen("class");
-        } else if (STARTS_WITH(walk + 1, "instance")) {
-            outwalk += sprintf(outwalk, "%s", escaped_instance);
-            walk += strlen("instance");
-        } else {
-            *(outwalk++) = *walk;
-        }
-    }
-    *outwalk = '\0';
-
-    i3String *formatted = i3string_from_utf8(buffer);
-    i3string_set_markup(formatted, font_is_pango());
-
-    FREE(escaped_title);
-    FREE(escaped_class);
-    FREE(escaped_instance);
-
-    return formatted;
-}

src/x.c

@@ -528,20 +528,23 @@ void x_draw_decoration(Con *con) {
 
     struct Window *win = con->window;
     if (win == NULL) {
-        /* we have a split container which gets a representation
-         * of its children as title
-         */
+        i3String *title;
+        if (con->title_format == NULL) {
             char *_title;
             char *tree = con_get_tree_representation(con);
             sasprintf(&_title, "i3: %s", tree);
             free(tree);
 
-        i3String *title = i3string_from_utf8(_title);
+            title = i3string_from_utf8(_title);
+            FREE(_title);
+        } else {
+            title = con_parse_title_format(con);
+        }
+
         draw_util_text(title, &(parent->frame_buffer),
                        p->color->text, p->color->background,
                        con->deco_rect.x + 2, con->deco_rect.y + text_offset_y,
                        con->deco_rect.width - 2);
-        FREE(_title);
         I3STRING_FREE(title);
 
         goto after_title;
@@ -599,12 +602,12 @@ void x_draw_decoration(Con *con) {
         FREE(formatted_mark);
     }
 
-    i3String *title = win->title_format == NULL ? win->name : window_parse_title_format(win);
+    i3String *title = con->title_format == NULL ? win->name : con_parse_title_format(con);
     draw_util_text(title, &(parent->frame_buffer),
                    p->color->text, p->color->background,
                    con->deco_rect.x + logical_px(2) + indent_px, con->deco_rect.y + text_offset_y,
                    con->deco_rect.width - logical_px(2) - indent_px - mark_width - logical_px(2));
-    if (win->title_format != NULL)
+    if (con->title_format != NULL)
         I3STRING_FREE(title);
 
 after_title: