backend: X11 后端添加获取窗口 metadata 信息方式

src/backend/x11/backend.c

@@ -13,10 +13,47 @@
 
 #include "backend/output_utils.h"
 #include "base/log.h"
+#include "base/macros.h"
 #include "base/memory.h"
 #include "core/types.h"
 #include "internal.h" /* IWYU pragma: keep */
 
+typedef struct atom_item_t {
+  const char *name;
+  size_t len;
+  xcb_atom_t *atom;
+} atom_item_t;
+
+static void atoms_init(backend_t *backend) {
+  xcb_connection_t *conn = backend->conn;
+  atoms_t *atoms = &backend->atoms;
+
+  atom_item_t atom_list[] = {
+    {"COMPOUND_TEXT", sizeof("COMPOUND_TEXT") - 1, &atoms->COMPOUND_TEXT},
+    {"UTF8_STRING", sizeof("UTF8_STRING") - 1, &atoms->UTF8_STRING},
+
+    {"WM_WINDOW_ROLE", sizeof("WM_WINDOW_ROLE") - 1, &atoms->WM_WINDOW_ROLE},
+    {"WM_NAME", sizeof("WM_NAME") - 1, &atoms->WM_NAME},
+    {"_NET_WM_NAME", sizeof("_NET_WM_NAME") - 1, &atoms->_NET_WM_NAME},
+  };
+
+  xcb_intern_atom_cookie_t cookies[countof(atom_list)];
+  for (size_t i = 0; i < countof(atom_list); ++i) {
+    const atom_item_t *atom = &atom_list[i];
+    cookies[i] = xcb_intern_atom_unchecked(conn, false, atom->len, atom->name);
+  }
+
+  xcb_intern_atom_reply_t *reply = nullptr;
+  for (size_t i = 0; i < countof(atom_list); ++i) {
+    reply = xcb_intern_atom_reply(conn, cookies[i], nullptr);
+    if (!reply) continue;
+
+    atom_item_t *atom = &atom_list[i];
+    *atom->atom = reply->atom;
+    p_delete(&reply);
+  }
+}
+
 backend_t *backend_create(const char *display_name) {
   int screen_num = 0;
   xcb_connection_t *conn = xcb_connect(display_name, &screen_num);
@@ -63,6 +100,8 @@ backend_t *backend_create(const char *display_name) {
     backend->have_xfixes = false;
   }
 
+  atoms_init(backend);
+
   return backend;
 }
 

src/backend/x11/event.c

@@ -1,21 +1,32 @@
+#include "core/event.h"
+
 #include <stdio.h>
 #include <xcb/xcb.h>
 #include <xcb/xcb_event.h>
 #include <xcb/xproto.h>
 
+#include "backend/x11/window.h"
 #include "base/memory.h"
 #include "core/backend.h"
+#include "core/window.h"
 #include "internal.h" /* IWYU pragma: keep */
 
-static bool handle_map_request(event_t *event,
+static bool handle_map_request(backend_t *backend, event_t *event,
                                const xcb_map_request_event_t *xcb_event) {
   p_clear(event, 1);
+  xcb_window_t window = xcb_event->window;
   event->type = ZDWM_EVENT_WINDOW_MAP_REQUEST;
+  event->data.window_map_request.window = window;
+  window_metadata_t *metadata = &event->data.window_map_request.metadata;
+  metadata->app_id = window_get_role(backend, window);
+  metadata->title = window_get_title(backend, window);
+  window_get_class(backend, window, &metadata->class_name,
+                   &metadata->instance_name);
   /* TODO: */
   return true;
 }
 
-static bool handle_unmap_notify(event_t *event,
+static bool handle_unmap_notify(backend_t *backend, event_t *event,
                                 const xcb_unmap_notify_event_t *xcb_event) {
   p_clear(event, 1);
   event->type = ZDWM_EVENT_WINDOW_REMOVE;
@@ -23,7 +34,7 @@ static bool handle_unmap_notify(event_t *event,
   return true;
 }
 
-static bool handle_destroy_notify(event_t *event,
+static bool handle_destroy_notify(backend_t *backend, event_t *event,
                                   const xcb_destroy_notify_event_t *xcb_event) {
   p_clear(event, 1);
   event->type = ZDWM_EVENT_WINDOW_REMOVE;
@@ -32,7 +43,8 @@ static bool handle_destroy_notify(event_t *event,
 }
 
 static bool handle_configure_request(
-  event_t *event, const xcb_configure_request_event_t *xcb_event) {
+  backend_t *backend, event_t *event,
+  const xcb_configure_request_event_t *xcb_event) {
   p_clear(event, 1);
   event->type = ZDWM_EVENT_CONFIGURE_REQUEST;
   /* TODO: */
@@ -52,9 +64,9 @@ bool backend_next_event(backend_t *backend, event_t *event) {
     printf("xcb event type: %u\n", response_type);
 
     switch (response_type) {
-#define EVENT(type, handler)                     \
+#define EVENT(type, handler)                              \
-  case type:                                     \
+  case type:                                              \
-    handled = handler(event, (void *)raw_event); \
+    handled = handler(backend, event, (void *)raw_event); \
     break
 
       EVENT(XCB_MAP_REQUEST, handle_map_request);

src/backend/x11/internal.h

@@ -1,12 +1,23 @@
 #pragma once
 
 #include <xcb/xcb.h>
+#include <xcb/xproto.h>
 
 #include "core/backend.h" /* IWYU pragma: keep */
 
+typedef struct atoms_t {
+  xcb_atom_t COMPOUND_TEXT;
+  xcb_atom_t UTF8_STRING;
+  xcb_atom_t WM_WINDOW_ROLE;
+  xcb_atom_t WM_NAME;
+  xcb_atom_t _NET_WM_NAME;
+} atoms_t;
+
 struct backend_t {
   xcb_connection_t *conn;
   xcb_screen_t *screen;
   int screenp;
   bool have_xfixes;
+
+  atoms_t atoms;
 };

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);
+}

src/backend/x11/window.h

@@ -0,0 +1,33 @@
+#pragma once
+
+#include <xcb/xproto.h>
+
+#include "core/backend.h"
+
+/**
+ * @brief 获取窗口的 role 属性
+ * @param backend 后端实例指针
+ * @param window 目标窗口
+ * @return 返回窗口的 role 属性字符串，调用者持有其内存并负责调用 free 释放
+ */
+char *window_get_role(backend_t *backend, xcb_window_t window);
+
+/**
+ * @brief 获取窗口标题
+ * @details 获取窗口的 _NET_WM_NAME/WM_NAME 属性作为其 title
+ * @param backend 后端实例指针
+ * @param window 目标窗口
+ * @return 返回窗口标题字符串，由调用者持有其内存并负责调用 free 释放
+ */
+char *window_get_title(backend_t *backend, xcb_window_t window);
+
+/**
+ * @brief 获取窗口的 class 和 instance 信息
+ * @param backend 后端实例指针
+ * @param window 目标窗口
+ * @param class_out class 信息返回指针，调用者持有其内存并负责调用 free 释放
+ * @param instance_out instance 信息返回指针，调用者持有其内存并负责调用 free
+ * 释放
+ */
+void window_get_class(backend_t *backend, xcb_window_t window, char **class_out,
+                      char **instance_out);

src/base/memory.h

@@ -24,6 +24,12 @@ static inline char *p_strdup(const char *text) {
   return r;
 }
 
+static inline char *p_strndup(const char *text, size_t n) {
+  char *r = strndup(text, n);
+  if (!r) abort();
+  return r;
+}
+
 static inline char *p_strdup_nullable(const char *text) {
   if (!text) return nullptr;
   return p_strdup(text);

src/core/window.h

@@ -45,10 +45,10 @@ typedef struct window_props_t {
 } window_props_t;
 
 typedef struct window_metadata_t {
-  const char *title;
+  char *title;
-  const char *app_id;
+  char *app_id; /* X11 中将其当 role 用 */
-  const char *class_name;
+  char *class_name;
-  const char *instance_name;
+  char *instance_name;
 } window_metadata_t;
 
 typedef struct window_geometry_t {

tests/core/CMakeLists.txt

@@ -9,6 +9,7 @@ add_executable(${TEST_APP_NAME}
     ${SOURCE_DIR}/config/runtime_config.c
     ${SOURCE_DIR}/backend/x11/backend.c
     ${SOURCE_DIR}/backend/x11/event.c
+    ${SOURCE_DIR}/backend/x11/window.c
     ${SOURCE_DIR}/core/layer.c
     ${SOURCE_DIR}/core/layout.c
     ${SOURCE_DIR}/core/runtime.c