Implement title_format

This implements the title_format command, with a new placeholder %shell
which gets substituted with the view type (xwayland, xdg_shell_v6 or
wl_shell).

Example config:

    for_window [title=".*"] title_format %title (class=%class instance=%instance shell=%shell)

1 files changed, 142 insertions, 0 deletions

diff --git a/sway/tree/view.c b/sway/tree/view.c
index 84962306..4a01f096 100644
--- a/sway/tree/view.c
+++ b/sway/tree/view.c
@@ -1,3 +1,4 @@
+#define _POSIX_C_SOURCE 200809L
 #include <stdlib.h>
 #include <wayland-server.h>
 #include <wlr/render/wlr_renderer.h>
@@ -67,6 +68,18 @@ const char *view_get_instance(struct sway_view *view) {
         return NULL;
 }
 
+const char *view_get_type(struct sway_view *view) {
+        switch(view->type) {
+        case SWAY_VIEW_WL_SHELL:
+                return "wl_shell";
+        case SWAY_VIEW_XDG_SHELL_V6:
+                return "xdg_shell_v6";
+        case SWAY_VIEW_XWAYLAND:
+                return "xwayland";
+        }
+        return "unknown";
+}
+
 void view_configure(struct sway_view *view, double ox, double oy, int width,
                 int height) {
         if (view->impl->configure) {
@@ -348,6 +361,11 @@ void view_unmap(struct sway_view *view) {
         view->swayc = NULL;
         view->surface = NULL;
 
+        if (view->title_format) {
+                free(view->title_format);
+                view->title_format = NULL;
+        }
+
         if (parent->type == C_OUTPUT) {
                 arrange_output(parent);
         } else {
@@ -475,3 +493,127 @@ void view_child_destroy(struct sway_view_child *child) {
                 free(child);
         }
 }
+
+static char *parse_title_format(struct sway_view *view) {
+        if (!view->title_format || strcmp(view->title_format, "%title") == 0) {
+                return strdup(view_get_title(view));
+        }
+        const char *title = view_get_title(view);
+        const char *class = view_get_class(view);
+        const char *instance = view_get_instance(view);
+        const char *shell = view_get_type(view);
+        size_t title_len = title ? strlen(title) : 0;
+        size_t class_len = class ? strlen(class) : 0;
+        size_t instance_len = instance ? strlen(instance) : 0;
+        size_t shell_len = shell ? strlen(shell) : 0;
+
+        // First, determine the length
+        size_t len = 0;
+        char *format = view->title_format;
+        char *next = strchr(format, '%');
+        while (next) {
+                len += next - format;
+                format = next;
+
+                if (strncmp(next, "%title", 6) == 0) {
+                        len += title_len;
+                        format += 6;
+                } else if (strncmp(next, "%class", 6) == 0) {
+                        len += class_len;
+                        format += 6;
+                } else if (strncmp(next, "%instance", 9) == 0) {
+                        len += instance_len;
+                        format += 9;
+                } else if (strncmp(next, "%shell", 6) == 0) {
+                        len += shell_len;
+                        format += 6;
+                } else {
+                        ++format;
+                        ++len;
+                }
+                next = strchr(format, '%');
+        }
+        len += strlen(format);
+
+        char *buffer = calloc(len + 1, 1);
+        if (!sway_assert(buffer, "Unable to allocate title string")) {
+                return NULL;
+        }
+
+        // Now build the title
+        format = view->title_format;
+        next = strchr(format, '%');
+        while (next) {
+                // Copy everything up to the %
+                strncat(buffer, format, next - format);
+                format = next;
+
+                if (strncmp(next, "%title", 6) == 0) {
+                        if (title) {
+                                strcat(buffer, title);
+                        }
+                        format += 6;
+                } else if (strncmp(next, "%class", 6) == 0) {
+                        if (class) {
+                                strcat(buffer, class);
+                        }
+                        format += 6;
+                } else if (strncmp(next, "%instance", 9) == 0) {
+                        if (instance) {
+                                strcat(buffer, instance);
+                        }
+                        format += 9;
+                } else if (strncmp(next, "%shell", 6) == 0) {
+                        strcat(buffer, shell);
+                        format += 6;
+                } else {
+                        strcat(buffer, "%");
+                        ++format;
+                }
+                next = strchr(format, '%');
+        }
+        strcat(buffer, format);
+
+        return buffer;
+}
+
+void view_update_title(struct sway_view *view, bool force) {
+        if (!view->swayc) {
+                return;
+        }
+        const char *title = view_get_title(view);
+
+        if (!force) {
+                if (title && view->swayc->name && strcmp(title, view->swayc->name) == 0) {
+                        return;
+                }
+                if (!title && !view->swayc->name) {
+                        return;
+                }
+        }
+
+        if (title) {
+                if (view->swayc->name) {
+                        free(view->swayc->name);
+                }
+                if (view->swayc->formatted_title) {
+                        free(view->swayc->formatted_title);
+                }
+                view->swayc->name = strdup(title);
+                view->swayc->formatted_title = parse_title_format(view);
+        } else {
+                free(view->swayc->name);
+                free(view->swayc->formatted_title);
+                view->swayc->name = NULL;
+                view->swayc->formatted_title = NULL;
+        }
+        container_calculate_title_height(view->swayc);
+        container_update_title_textures(view->swayc);
+        container_notify_child_title_changed(view->swayc->parent);
+
+        size_t prev_max_height = config->font_height;
+        config_find_font_height(false);
+        if (config->font_height != prev_max_height) {
+                arrange_root();
+        }
+}