wayland: add --wayland-display option

DOCS/interface-changes/wayland-display.txt

@@ -0,0 +1 @@
+add `--wayland-display` option to connect to a Wayland display other than the one given by `WAYLAND_DISPLAY`

DOCS/man/options.rst

@@ -6521,6 +6521,19 @@ them.
     (default) will automatically switch between telling the compositor the content
     is a photo, video or possibly none depending on internal heuristics.
 
+``--wayland-display=<string>``
+    Connect to this Wayland display instead of the one given by the
+    ``WAYLAND_DISPLAY`` environment variable (default: unset). This is either
+    a socket name relative to ``XDG_RUNTIME_DIR`` or an absolute path. Not
+    setting this or setting it to the empty string uses the environment as
+    usual. If ``WAYLAND_SOCKET`` is set, it takes precedence over this option.
+
+    This applies to the VO and to the Wayland clipboard backend. It is useful
+    for applications embedding mpv that proxy its Wayland connection, since it
+    redirects mpv without changing ``WAYLAND_DISPLAY`` for the whole process.
+    Changes reconnect the clipboard immediately and take effect for the VO the
+    next time it is created.
+
 ``--wayland-edge-pixels-pointer=<value>``
     Defines the size of an edge border (default: 16) to initiate client side
     resize events in the wayland contexts with the mouse or tablet. This is only

options/options.c

@@ -216,6 +216,7 @@ static const m_option_t mp_vo_opt_list[] = {
         {"photo", 1}, {"video", 2}, {"game", 3})},
     {"wayland-disable-vsync", OPT_BOOL(wl_disable_vsync),
         .deprecation_message = "replaced by --wayland-internal-vsync=no"},
+    {"wayland-display", OPT_STRING(wayland_display), .flags = UPDATE_CLIPBOARD},
     {"wayland-internal-vsync", OPT_CHOICE(wl_internal_vsync,
         {"no", 0}, {"auto", 1}, {"yes", 2})},
     {"wayland-edge-pixels-pointer", OPT_INT(wl_edge_pixels_pointer),

options/options.h

@@ -29,6 +29,7 @@ typedef struct mp_vo_opts {
     char *winname;
     char *appid;
     char *wayland_session;
+    char *wayland_display;
     int x11_netwm;
     int x11_bypass_compositor;
     int x11_present;

player/clipboard/clipboard-wayland.c

@@ -336,12 +336,18 @@ static void clipboard_wayland_uninit(struct clipboard_wayland_priv *wl)
         wl_display_disconnect(wl->display);
 }
 
-static bool clipboard_wayland_init(struct clipboard_wayland_priv *wl, bool monitor)
+static bool clipboard_wayland_init(struct clipboard_wayland_priv *wl, bool monitor,
+                                   const char *display_name)
 {
-    if (!getenv("WAYLAND_DISPLAY") && !getenv("WAYLAND_SOCKET"))
+    if (display_name && !display_name[0])
+        display_name = NULL;
+    if (!display_name && !getenv("WAYLAND_DISPLAY") &&
+        !getenv("WAYLAND_SOCKET"))
+    {
         goto err;
+    }
 
-    wl->display = wl_display_connect(NULL);
+    wl->display = wl_display_connect(display_name);
     if (!wl->display)
         goto err;
 
@@ -520,7 +526,8 @@ static int init(struct clipboard_ctx *cl, struct clipboard_init_params *params)
 
     if (mp_make_wakeup_pipe(priv->message_pipe) < 0)
         goto pipe_err;
-    if (!clipboard_wayland_init(priv, params->flags & CLIPBOARD_INIT_ENABLE_MONITORING))
+    if (!clipboard_wayland_init(priv, params->flags & CLIPBOARD_INIT_ENABLE_MONITORING,
+                                params->wayland_display))
         goto init_err;
     if (mp_thread_create(&priv->thread, clipboard_thread, cl->priv))
         goto thread_err;

player/clipboard/clipboard-x11.c

@@ -67,9 +67,12 @@ static void clipboard_x11_uninit(struct clipboard_x11_priv *x11)
         XCloseDisplay(x11->display);
 }
 
-static bool clipboard_x11_init(struct clipboard_x11_priv *x11, bool xwayland, bool monitor)
+static bool clipboard_x11_init(struct clipboard_x11_priv *x11, bool xwayland, bool monitor,
+                               const char *wayland_display)
 {
-    if (!xwayland && (getenv("WAYLAND_DISPLAY") || getenv("WAYLAND_SOCKET"))) {
+    bool wayland = (wayland_display && wayland_display[0]) ||
+                   getenv("WAYLAND_DISPLAY") || getenv("WAYLAND_SOCKET");
+    if (!xwayland && wayland) {
         MP_VERBOSE(x11, "Stopping init due to suspected wayland environment\n");
         goto err;
     }
@@ -279,7 +282,8 @@ static int init(struct clipboard_ctx *cl, struct clipboard_init_params *params)
     if (mp_make_wakeup_pipe(priv->message_pipe) < 0)
         goto pipe_err;
     if (!clipboard_x11_init(priv, params->flags & CLIPBOARD_INIT_ENABLE_XWAYLAND,
-                            params->flags & CLIPBOARD_INIT_ENABLE_MONITORING))
+                            params->flags & CLIPBOARD_INIT_ENABLE_MONITORING,
+                            params->wayland_display))
         goto init_err;
     if (mp_thread_create(&priv->thread, clipboard_thread, cl->priv))
         goto thread_err;

player/clipboard/clipboard.c

@@ -199,6 +199,7 @@ void reinit_clipboard(struct MPContext *mpctx)
         struct clipboard_init_params params = {
             .mpctx = mpctx,
             .backends = opts->backends,
+            .wayland_display = mpctx->opts->vo->wayland_display,
         };
         params.flags |= opts->monitor ? CLIPBOARD_INIT_ENABLE_MONITORING : 0;
         params.flags |= opts->xwayland ? CLIPBOARD_INIT_ENABLE_XWAYLAND : 0;

player/clipboard/clipboard.h

@@ -56,6 +56,7 @@ struct clipboard_init_params {
     int flags;
     struct MPContext *mpctx; // For clipboard_vo only
     struct m_obj_settings *backends;
+    const char *wayland_display; // For clipboard_wayland and clipboard_x11
 };
 
 struct clipboard_access_params {

video/out/wayland_common.c

@@ -4528,9 +4528,15 @@ bool vo_wayland_valid_format(struct vo_wayland_state *wl, uint32_t drm_format, u
 
 bool vo_wayland_init(struct vo *vo)
 {
-    if (vo->probing && !getenv("WAYLAND_DISPLAY") && !getenv("WAYLAND_SOCKET")) {
-        MP_VERBOSE(vo, "Skipping Wayland because neither WAYLAND_DISPLAY or "
-            "WAYLAND_SOCKET is set\n");
+    const char *display_name = vo->opts->wayland_display;
+    if (display_name && !display_name[0])
+        display_name = NULL;
+
+    if (vo->probing && !display_name && !getenv("WAYLAND_DISPLAY") &&
+        !getenv("WAYLAND_SOCKET"))
+    {
+        MP_VERBOSE(vo, "Skipping Wayland because neither --wayland-display, "
+            "WAYLAND_DISPLAY or WAYLAND_SOCKET is set\n");
         goto err;
     }
 
@@ -4558,7 +4564,13 @@ bool vo_wayland_init(struct vo *vo)
     wl_list_init(&wl->seat_list);
     wl_list_init(&wl->tranche_list);
 
-    wl->display = wl_display_connect(NULL);
+    if (display_name && getenv("WAYLAND_SOCKET")) {
+        MP_WARN(wl, "WAYLAND_SOCKET is set and takes precedence over "
+                "--wayland-display.\n");
+    }
+    MP_VERBOSE(wl, "Connecting to Wayland display: %s\n",
+               display_name ? display_name : "(default)");
+    wl->display = wl_display_connect(display_name);
     if (!wl->display) {
         MP_MSG(wl, vo->probing ? MSGL_V : MSGL_FATAL,
                "Couldn't connect to Wayland display: %s\n", strerror(errno));