Initial commit

1 files changed, 329 insertions, 0 deletions

diff --git a/src/gsr-x11-window-picker.c b/src/gsr-x11-window-picker.c
new file mode 100644
index 0000000..83f1aa2
--- /dev/null
+++ b/src/gsr-x11-window-picker.c
@@ -0,0 +1,329 @@
+#include "gsr-x11-window-picker.h"
+
+#include <stdlib.h>
+#include <string.h>
+#include <X11/Xutil.h>
+#include <X11/cursorfont.h>
+#include <X11/keysym.h>
+#include <X11/Xatom.h>
+
+#include <glib.h>
+#include <glib-unix.h>
+
+/* ── Internal struct ─────────────────────────────────────────────── */
+
+struct _GsrX11WindowPicker {
+    Display                   *display;     /* own connection */
+    Window                     root;
+    Cursor                     crosshair;
+    GsrX11WindowPickCallback   callback;
+    void                      *userdata;
+    GSource                   *source;
+    guint                      source_id;
+    bool                       finished;    /* prevents double callback */
+};
+
+/* ── X11 tree walker ─────────────────────────────────────────────── */
+
+/**
+ * Check if a window has a given atom property.
+ */
+static bool
+window_has_atom(Display *display, Window window, Atom atom)
+{
+    Atom type_ret;
+    int format_ret;
+    unsigned long nitems, bytes_after;
+    unsigned char *data = NULL;
+
+    int rc = XGetWindowProperty(display, window, atom,
+                                0, 0, False, AnyPropertyType,
+                                &type_ret, &format_ret,
+                                &nitems, &bytes_after, &data);
+    if (data)
+        XFree(data);
+
+    return rc == Success && type_ret != None;
+}
+
+/**
+ * Walk the window tree looking for the first child with _NET_WM_STATE,
+ * which is the "real" toplevel window managed by the WM.
+ */
+static Window
+find_toplevel_window(Display *display, Window window)
+{
+    if (window == None)
+        return None;
+
+    Atom wm_state = XInternAtom(display, "_NET_WM_STATE", False);
+    if (!wm_state)
+        return None;
+
+    if (window_has_atom(display, window, wm_state))
+        return window;
+
+    Window root, parent;
+    Window *children = NULL;
+    unsigned int n_children = 0;
+
+    if (!XQueryTree(display, window, &root, &parent, &children, &n_children)
+        || !children)
+        return None;
+
+    Window found = None;
+
+    /* First pass: direct children with _NET_WM_STATE */
+    for (int i = (int)n_children - 1; i >= 0; i--) {
+        if (children[i] && window_has_atom(display, children[i], wm_state)) {
+            found = children[i];
+            goto done;
+        }
+    }
+    /* Second pass: recurse */
+    for (int i = (int)n_children - 1; i >= 0; i--) {
+        if (children[i]) {
+            Window w = find_toplevel_window(display, children[i]);
+            if (w != None) {
+                found = w;
+                goto done;
+            }
+        }
+    }
+
+done:
+    XFree(children);
+    return found;
+}
+
+/**
+ * Get the WM_NAME of a window.  Returns a g_malloc'd string, or NULL.
+ */
+static char *
+get_window_name(Display *display, Window window)
+{
+    if (window == None)
+        return NULL;
+
+    /* Try _NET_WM_NAME first (UTF-8) */
+    Atom net_wm_name = XInternAtom(display, "_NET_WM_NAME", False);
+    Atom utf8_string = XInternAtom(display, "UTF8_STRING", False);
+
+    if (net_wm_name && utf8_string) {
+        Atom type_ret;
+        int format_ret;
+        unsigned long nitems, bytes_after;
+        unsigned char *data = NULL;
+
+        int rc = XGetWindowProperty(display, window, net_wm_name,
+                                    0, 1024, False, utf8_string,
+                                    &type_ret, &format_ret,
+                                    &nitems, &bytes_after, &data);
+        if (rc == Success && data && nitems > 0) {
+            char *name = g_strdup((const char *)data);
+            XFree(data);
+            return name;
+        }
+        if (data)
+            XFree(data);
+    }
+
+    /* Fallback: XGetWMName */
+    XTextProperty wm_name;
+    if (XGetWMName(display, window, &wm_name) && wm_name.nitems > 0) {
+        char **list = NULL;
+        int count = 0;
+        char *result = NULL;
+
+        if (Xutf8TextPropertyToTextList(display, &wm_name, &list, &count) >= 0
+            && list && count > 0 && list[0])
+        {
+            result = g_strdup(list[0]);
+        } else {
+            /* Last resort: just copy the raw value */
+            result = g_strndup((const char *)wm_name.value, wm_name.nitems);
+        }
+
+        if (list)
+            XFreeStringList(list);
+        if (wm_name.value)
+            XFree(wm_name.value);
+
+        return result;
+    }
+
+    return NULL;
+}
+
+/* ── Finish the pick ─────────────────────────────────────────────── */
+
+static void
+finish_pick(GsrX11WindowPicker *self, Window window, char *name)
+{
+    if (self->finished)
+        return;
+    self->finished = true;
+
+    XUngrabPointer(self->display, CurrentTime);
+    XUngrabKeyboard(self->display, CurrentTime);
+    XSync(self->display, False);
+
+    GsrX11WindowPickResult result = {
+        .window = window,
+        .name   = name,
+    };
+    self->callback(&result, self->userdata);
+
+    /* Self-destroy after callback */
+    gsr_x11_window_picker_free(self);
+}
+
+/* ── GSource dispatch — poll X events ────────────────────────────── */
+
+static gboolean
+picker_source_prepare(GSource *source G_GNUC_UNUSED, gint *timeout)
+{
+    *timeout = -1;
+    return FALSE;
+}
+
+static gboolean
+picker_source_check(GSource *source G_GNUC_UNUSED)
+{
+    return TRUE;
+}
+
+static gboolean
+picker_source_dispatch(GSource *source G_GNUC_UNUSED,
+                       GSourceFunc callback G_GNUC_UNUSED,
+                       gpointer user_data)
+{
+    GsrX11WindowPicker *self = user_data;
+
+    if (self->finished)
+        return G_SOURCE_REMOVE;
+
+    while (XPending(self->display)) {
+        XEvent ev;
+        XNextEvent(self->display, &ev);
+
+        if (ev.type == ButtonPress) {
+            Window clicked = ev.xbutton.subwindow;
+            if (clicked == None)
+                clicked = ev.xbutton.window;
+
+            /* Walk tree to find the real toplevel */
+            Window toplevel = find_toplevel_window(self->display, clicked);
+            if (toplevel != None)
+                clicked = toplevel;
+
+            if (clicked == None || clicked == self->root) {
+                /* Clicked root / empty space — cancel */
+                finish_pick(self, None, NULL);
+                return G_SOURCE_REMOVE;
+            }
+
+            char *name = get_window_name(self->display, clicked);
+            if (!name)
+                name = g_strdup("(no name)");
+
+            finish_pick(self, clicked, name);
+            return G_SOURCE_REMOVE;
+        }
+
+        if (ev.type == KeyPress) {
+            KeySym ks = XLookupKeysym(&ev.xkey, 0);
+            if (ks == XK_Escape) {
+                finish_pick(self, None, NULL);
+                return G_SOURCE_REMOVE;
+            }
+        }
+    }
+
+    return G_SOURCE_CONTINUE;
+}
+
+static GSourceFuncs picker_source_funcs = {
+    .prepare  = picker_source_prepare,
+    .check    = picker_source_check,
+    .dispatch = picker_source_dispatch,
+    .finalize = NULL,
+};
+
+/* ── Public API ──────────────────────────────────────────────────── */
+
+GsrX11WindowPicker *
+gsr_x11_window_picker_new(GsrX11WindowPickCallback callback,
+                           void *userdata)
+{
+    if (!callback)
+        return NULL;
+
+    /* Open our own X connection so we don't conflict with GDK */
+    Display *dpy = XOpenDisplay(NULL);
+    if (!dpy) {
+        g_warning("gsr_x11_window_picker: failed to open X display");
+        return NULL;
+    }
+
+    GsrX11WindowPicker *self = g_new0(GsrX11WindowPicker, 1);
+    self->display   = dpy;
+    self->root      = DefaultRootWindow(dpy);
+    self->callback  = callback;
+    self->userdata  = userdata;
+    self->finished  = false;
+
+    self->crosshair = XCreateFontCursor(dpy, XC_crosshair);
+
+    /* Grab pointer with crosshair */
+    int status = XGrabPointer(dpy, self->root, False,
+                              ButtonPressMask | ButtonReleaseMask,
+                              GrabModeAsync, GrabModeAsync,
+                              self->root, self->crosshair, CurrentTime);
+    if (status != GrabSuccess) {
+        g_warning("gsr_x11_window_picker: XGrabPointer failed (%d)", status);
+        XFreeCursor(dpy, self->crosshair);
+        XCloseDisplay(dpy);
+        g_free(self);
+        return NULL;
+    }
+
+    /* Also grab keyboard so we can detect Escape */
+    XGrabKeyboard(dpy, self->root, False,
+                  GrabModeAsync, GrabModeAsync, CurrentTime);
+
+    XSync(dpy, False);
+
+    /* Set up GSource to poll X events */
+    int x_fd = ConnectionNumber(dpy);
+    self->source = g_source_new(&picker_source_funcs, sizeof(GSource));
+    g_source_set_callback(self->source, NULL, self, NULL);
+    g_source_add_unix_fd(self->source, x_fd, G_IO_IN | G_IO_HUP | G_IO_ERR);
+    self->source_id = g_source_attach(self->source, NULL);
+
+    return self;
+}
+
+void
+gsr_x11_window_picker_free(GsrX11WindowPicker *self)
+{
+    if (!self)
+        return;
+
+    if (self->source) {
+        g_source_destroy(self->source);
+        g_source_unref(self->source);
+        self->source = NULL;
+    }
+
+    if (self->display) {
+        XUngrabPointer(self->display, CurrentTime);
+        XUngrabKeyboard(self->display, CurrentTime);
+        if (self->crosshair)
+            XFreeCursor(self->display, self->crosshair);
+        XCloseDisplay(self->display);
+        self->display = NULL;
+    }
+
+    g_free(self);
+}