backend: X11 后端添加获取窗口 metadata 信息方式

src/backend/x11/window.c

@@ -0,0 +1,63 @@
+#include "window.h"
+
+#include <stddef.h>
+#include <stdint.h>
+#include <xcb/xcb.h>
+#include <xcb/xcb_icccm.h>
+#include <xcb/xproto.h>
+
+#include "base/memory.h"
+#include "internal.h"
+
+static char *window_get_text_property(backend_t *backend, xcb_window_t window,
+                                      xcb_atom_t property) {
+  xcb_get_property_cookie_t cookie = xcb_get_property_unchecked(
+    backend->conn, false, window, property, XCB_ATOM_ANY, 0, UINT32_MAX);
+  xcb_get_property_reply_t *reply =
+    xcb_get_property_reply(backend->conn, cookie, nullptr);
+  if (!reply) return nullptr;
+
+  int length = xcb_get_property_value_length(reply);
+  char *value = (char *)xcb_get_property_value(reply);
+
+  char *text = nullptr;
+  if (length && reply->format == 8 &&
+      (reply->type == XCB_ATOM_STRING ||
+       reply->type == backend->atoms.UTF8_STRING ||
+       reply->type == backend->atoms.COMPOUND_TEXT)) {
+    text = p_strndup(value, (size_t)length);
+  }
+
+  p_delete(&reply);
+  return text;
+}
+
+char *window_get_role(backend_t *backend, xcb_window_t window) {
+  xcb_atom_t property = backend->atoms.WM_WINDOW_ROLE;
+  return window_get_text_property(backend, window, property);
+}
+
+char *window_get_title(backend_t *backend, xcb_window_t window) {
+  xcb_atom_t property = backend->atoms._NET_WM_NAME;
+  char *name = window_get_text_property(backend, window, property);
+  if (!name) {
+    property = backend->atoms.WM_NAME;
+    name = window_get_text_property(backend, window, property);
+  }
+  return name;
+}
+
+void window_get_class(backend_t *backend, xcb_window_t window, char **class_out,
+                      char **instance_out) {
+  xcb_icccm_get_wm_class_reply_t prop;
+  xcb_get_property_cookie_t cookie =
+    xcb_icccm_get_wm_class_unchecked(backend->conn, window);
+  if (!xcb_icccm_get_wm_class_reply(backend->conn, cookie, &prop, nullptr)) {
+    return;
+  }
+
+  if (class_out) *class_out = p_strdup_nullable(prop.class_name);
+  if (instance_out) *instance_out = p_strdup_nullable(prop.instance_name);
+
+  xcb_icccm_get_wm_class_reply_wipe(&prop);
+}