picom/src/x.c

// SPDX-License-Identifier: MPL-2.0
// Copyright (c) 2018 Yuxuan Shui <yshuiv7@gmail.com>
#include <stdbool.h>
#include <stdlib.h>

#include <X11/Xutil.h>
#include <xcb/xcb.h>
#include <xcb/xcb_renderutil.h>
#include <xcb/xfixes.h>
#include <xcb/sync.h>
#include <xcb/composite.h>
#include <xcb/damage.h>
#include <xcb/render.h>
#include <pixman.h>

#include "utils.h"
#include "region.h"
#include "compiler.h"
#include "common.h"
#include "kernel.h"
#include "x.h"
#include "log.h"
#include "backend/gl/glx.h"

/**
 * Get a specific attribute of a window.
 *
 * Returns a blank structure if the returned type and format does not
 * match the requested type and format.
 *
 * @param ps current session
 * @param w window
 * @param atom atom of attribute to fetch
 * @param length length to read
 * @param rtype atom of the requested type
 * @param rformat requested format
 * @return a <code>winprop_t</code> structure containing the attribute
 *    and number of items. A blank one on failure.
 */
winprop_t
wid_get_prop_adv(const session_t *ps, xcb_window_t w, xcb_atom_t atom, long offset,
    long length, xcb_atom_t rtype, int rformat) {
  xcb_get_property_reply_t *r = xcb_get_property_reply(ps->c,
    xcb_get_property(ps->c, 0, w, atom, rtype, offset, length), NULL);

  if (r && xcb_get_property_value_length(r) &&
      (rtype == XCB_GET_PROPERTY_TYPE_ANY || r->type == rtype) &&
      (!rformat || r->format == rformat) &&
      (r->format == 8 || r->format == 16 || r->format == 32))
  {
    int len = xcb_get_property_value_length(r);
    return (winprop_t) {
      .ptr = xcb_get_property_value(r),
      .nitems = len/(r->format/8),
      .type = r->type,
      .format = r->format,
      .r = r,
    };
  }

  free(r);
  return (winprop_t) {
    .ptr = NULL,
    .nitems = 0,
    .type = XCB_GET_PROPERTY_TYPE_ANY,
    .format = 0
  };
}

/**
 * Get the value of a type-<code>xcb_window_t</code> property of a window.
 *
 * @return the value if successful, 0 otherwise
 */
xcb_window_t
wid_get_prop_window(session_t *ps, xcb_window_t wid, xcb_atom_t aprop) {
  // Get the attribute
  xcb_window_t p = XCB_NONE;
  winprop_t prop = wid_get_prop(ps, wid, aprop, 1L, XCB_ATOM_WINDOW, 32);

  // Return it
  if (prop.nitems) {
    p = *prop.p32;
  }

  free_winprop(&prop);

  return p;
}

/**
 * Get the value of a text property of a window.
 */
bool wid_get_text_prop(session_t *ps, xcb_window_t wid, xcb_atom_t prop,
    char ***pstrlst, int *pnstr) {
  XTextProperty text_prop = { NULL, XCB_NONE, 0, 0 };

  if (!(XGetTextProperty(ps->dpy, wid, &text_prop, prop) && text_prop.value))
    return false;

  if (Success !=
      XmbTextPropertyToTextList(ps->dpy, &text_prop, pstrlst, pnstr)
      || !*pnstr) {
    *pnstr = 0;
    if (*pstrlst)
      XFreeStringList(*pstrlst);
    cxfree(text_prop.value);
    return false;
  }

  cxfree(text_prop.value);
  return true;
}

// A cache of pict formats. We assume they don't change during the lifetime
// of compton
static thread_local xcb_render_query_pict_formats_reply_t *g_pictfmts = NULL;

static inline void x_get_server_pictfmts(xcb_connection_t *c) {
  if (g_pictfmts)
    return;
  xcb_generic_error_t *e = NULL;
  // Get window picture format
  g_pictfmts =
    xcb_render_query_pict_formats_reply(c,
        xcb_render_query_pict_formats(c), &e);
  if (e || !g_pictfmts) {
    log_fatal("failed to get pict formats\n");
    abort();
  }
}

const xcb_render_pictforminfo_t *
x_get_pictform_for_visual(xcb_connection_t *c, xcb_visualid_t visual) {
  x_get_server_pictfmts(c);

  xcb_render_pictvisual_t *pv = xcb_render_util_find_visual_format(g_pictfmts, visual);
  for(xcb_render_pictforminfo_iterator_t i =
      xcb_render_query_pict_formats_formats_iterator(g_pictfmts); i.rem;
      xcb_render_pictforminfo_next(&i)) {
    if (i.data->id == pv->format) {
      return i.data;
    }
  }
  return NULL;
}

int x_get_visual_depth(xcb_connection_t *c, xcb_visualid_t visual) {
  auto setup = xcb_get_setup(c);
  for (auto screen = xcb_setup_roots_iterator(setup); screen.rem; xcb_screen_next(&screen)) {
    for (auto depth = xcb_screen_allowed_depths_iterator(screen.data); depth.rem; xcb_depth_next(&depth)) {
      const int len = xcb_depth_visuals_length(depth.data);
      const xcb_visualtype_t *visuals = xcb_depth_visuals(depth.data);
      for (int i = 0; i < len; i++) {
        if (visual == visuals[i].visual_id) {
          return depth.data->depth;
        }
      }
    }
  }
  return -1;
}

xcb_render_picture_t
x_create_picture_with_pictfmt_and_pixmap(
  xcb_connection_t *c, const xcb_render_pictforminfo_t * pictfmt,
  xcb_pixmap_t pixmap, unsigned long valuemask,
  const xcb_render_create_picture_value_list_t *attr)
{
  void *buf = NULL;
  if (attr) {
    xcb_render_create_picture_value_list_serialize(&buf, valuemask, attr);
    if (!buf) {
      log_error("failed to serialize picture attributes");
      return XCB_NONE;
    }
  }

  xcb_render_picture_t tmp_picture = xcb_generate_id(c);
  xcb_generic_error_t *e =
    xcb_request_check(c, xcb_render_create_picture_checked(c, tmp_picture,
      pixmap, pictfmt->id, valuemask, buf));
  free(buf);
  if (e) {
    log_error("failed to create picture");
    return XCB_NONE;
  }
  return tmp_picture;
}

xcb_render_picture_t
x_create_picture_with_visual_and_pixmap(
  xcb_connection_t *c, xcb_visualid_t visual,
  xcb_pixmap_t pixmap, unsigned long valuemask,
  const xcb_render_create_picture_value_list_t *attr)
{
  const xcb_render_pictforminfo_t *pictfmt = x_get_pictform_for_visual(c, visual);
  return x_create_picture_with_pictfmt_and_pixmap(c, pictfmt, pixmap, valuemask, attr);
}

xcb_render_picture_t
x_create_picture_with_standard_and_pixmap(
  xcb_connection_t *c, xcb_pict_standard_t standard,
  xcb_pixmap_t pixmap, unsigned long valuemask,
  const xcb_render_create_picture_value_list_t *attr)
{
  x_get_server_pictfmts(c);

  auto pictfmt =
    xcb_render_util_find_standard_format(g_pictfmts, standard);
  assert(pictfmt);
  return x_create_picture_with_pictfmt_and_pixmap(c, pictfmt, pixmap, valuemask, attr);
}

/**
 * Create an picture.
 */
xcb_render_picture_t
x_create_picture_with_pictfmt(session_t *ps, int wid, int hei,
  const xcb_render_pictforminfo_t *pictfmt, unsigned long valuemask,
  const xcb_render_create_picture_value_list_t *attr)
{
  if (!pictfmt)
    pictfmt = x_get_pictform_for_visual(ps->c, ps->vis);

  if (!pictfmt) {
    log_fatal("Default visual is invalid");
    abort();
  }

  int depth = pictfmt->depth;

  xcb_pixmap_t tmp_pixmap = x_create_pixmap(ps->c, depth, ps->root, wid, hei);
  if (!tmp_pixmap)
    return XCB_NONE;

  xcb_render_picture_t picture =
    x_create_picture_with_pictfmt_and_pixmap(ps->c, pictfmt, tmp_pixmap, valuemask, attr);

  xcb_free_pixmap(ps->c, tmp_pixmap);

  return picture;
}

xcb_render_picture_t
x_create_picture_with_visual(session_t *ps, int w, int h,
  xcb_visualid_t visual, unsigned long valuemask,
  const xcb_render_create_picture_value_list_t *attr)
{
  auto pictfmt = x_get_pictform_for_visual(ps->c, visual);
  return x_create_picture_with_pictfmt(ps, w, h, pictfmt, valuemask, attr);
}

bool x_fetch_region(xcb_connection_t *c, xcb_xfixes_region_t r, pixman_region32_t *res) {
  xcb_generic_error_t *e = NULL;
  xcb_xfixes_fetch_region_reply_t *xr = xcb_xfixes_fetch_region_reply(c,
    xcb_xfixes_fetch_region(c, r), &e);
  if (!xr) {
    log_error("Failed to fetch rectangles");
    return false;
  }

  int nrect = xcb_xfixes_fetch_region_rectangles_length(xr);
  auto b = ccalloc(nrect, pixman_box32_t);
  xcb_rectangle_t *xrect = xcb_xfixes_fetch_region_rectangles(xr);
  for (int i = 0; i < nrect; i++) {
    b[i] = (pixman_box32_t) {
      .x1 = xrect[i].x,
      .y1 = xrect[i].y,
      .x2 = xrect[i].x + xrect[i].width,
      .y2 = xrect[i].y + xrect[i].height
    };
  }
  bool ret = pixman_region32_init_rects(res, b, nrect);
  free(b);
  free(xr);
  return ret;
}

void x_set_picture_clip_region(xcb_connection_t *c, xcb_render_picture_t pict,
    int clip_x_origin, int clip_y_origin, const region_t *reg) {
  int nrects;
  const rect_t *rects = pixman_region32_rectangles((region_t *)reg, &nrects);
  auto xrects = ccalloc(nrects, xcb_rectangle_t);
  for (int i = 0; i < nrects; i++)
    xrects[i] = (xcb_rectangle_t){
      .x = rects[i].x1,
      .y = rects[i].y1,
      .width = rects[i].x2 - rects[i].x1,
      .height = rects[i].y2 - rects[i].y1,
    };

  xcb_generic_error_t *e =
    xcb_request_check(c, xcb_render_set_picture_clip_rectangles_checked(c, pict,
      clip_x_origin, clip_y_origin, nrects, xrects));
  if (e)
    log_error("Failed to set clip region");
  free(e);
  free(xrects);
  return;
}

void x_clear_picture_clip_region(xcb_connection_t *c, xcb_render_picture_t pict) {
  xcb_render_change_picture_value_list_t v = {
    .clipmask = XCB_NONE
  };
  xcb_generic_error_t *e =
    xcb_request_check(c, xcb_render_change_picture(c, pict,
      XCB_RENDER_CP_CLIP_MASK, &v));
  if (e)
    log_error("failed to clear clip region");
  free(e);
  return;
}

enum {
  XSyncBadCounter = 0,
  XSyncBadAlarm = 1,
  XSyncBadFence = 2,
};

/**
 * X11 error handler function.
 *
 * XXX consider making this error to string
 */
void
x_print_error(unsigned long serial, uint8_t major, uint8_t minor, uint8_t error_code) {
  session_t * const ps = ps_g;

  int o = 0;
  const char *name = "Unknown";

  if (major == ps->composite_opcode
      && minor == XCB_COMPOSITE_REDIRECT_SUBWINDOWS) {
    log_fatal("Another composite manager is already running "
              "(and does not handle _NET_WM_CM_Sn correctly)");
    exit(1);
  }

#define CASESTRRET2(s)   case s: name = #s; break

  o = error_code - ps->xfixes_error;
  switch (o) {
    CASESTRRET2(XCB_XFIXES_BAD_REGION);
  }

  o = error_code - ps->damage_error;
  switch (o) {
    CASESTRRET2(XCB_DAMAGE_BAD_DAMAGE);
  }

  o = error_code - ps->render_error;
  switch (o) {
    CASESTRRET2(XCB_RENDER_PICT_FORMAT);
    CASESTRRET2(XCB_RENDER_PICTURE);
    CASESTRRET2(XCB_RENDER_PICT_OP);
    CASESTRRET2(XCB_RENDER_GLYPH_SET);
    CASESTRRET2(XCB_RENDER_GLYPH);
  }

#ifdef CONFIG_OPENGL
  if (ps->glx_exists) {
    o = error_code - ps->glx_error;
    switch (o) {
      CASESTRRET2(GLX_BAD_SCREEN);
      CASESTRRET2(GLX_BAD_ATTRIBUTE);
      CASESTRRET2(GLX_NO_EXTENSION);
      CASESTRRET2(GLX_BAD_VISUAL);
      CASESTRRET2(GLX_BAD_CONTEXT);
      CASESTRRET2(GLX_BAD_VALUE);
      CASESTRRET2(GLX_BAD_ENUM);
    }
  }
#endif

  if (ps->xsync_exists) {
    o = error_code - ps->xsync_error;
    switch (o) {
      CASESTRRET2(XSyncBadCounter);
      CASESTRRET2(XSyncBadAlarm);
      CASESTRRET2(XSyncBadFence);
    }
  }

  switch (error_code) {
    CASESTRRET2(BadAccess);
    CASESTRRET2(BadAlloc);
    CASESTRRET2(BadAtom);
    CASESTRRET2(BadColor);
    CASESTRRET2(BadCursor);
    CASESTRRET2(BadDrawable);
    CASESTRRET2(BadFont);
    CASESTRRET2(BadGC);
    CASESTRRET2(BadIDChoice);
    CASESTRRET2(BadImplementation);
    CASESTRRET2(BadLength);
    CASESTRRET2(BadMatch);
    CASESTRRET2(BadName);
    CASESTRRET2(BadPixmap);
    CASESTRRET2(BadRequest);
    CASESTRRET2(BadValue);
    CASESTRRET2(BadWindow);
  }

#undef CASESTRRET2

  log_debug("X error %d %s request %d minor %d serial %lu",
            error_code, name, major, minor, serial);
}

/**
 * Create a pixmap and check that creation succeeded.
 */
xcb_pixmap_t
x_create_pixmap(xcb_connection_t *c, uint8_t depth, xcb_drawable_t drawable, uint16_t width, uint16_t height) {
  xcb_pixmap_t pix = xcb_generate_id(c);
  xcb_void_cookie_t cookie = xcb_create_pixmap_checked(c, depth, pix, drawable, width, height);
  xcb_generic_error_t *err = xcb_request_check(c, cookie);
  if (err == NULL)
    return pix;

  log_error("Failed to create pixmap:");
  x_print_error(err->sequence, err->major_code, err->minor_code, err->error_code);
  free(err);
  return XCB_NONE;
}

/**
 * Validate a pixmap.
 *
 * Detect whether the pixmap is valid with XGetGeometry. Well, maybe there
 * are better ways.
 */
bool
x_validate_pixmap(xcb_connection_t *c, xcb_pixmap_t pixmap) {
  if (pixmap == XCB_NONE) {
    return false;
  }

  auto r = xcb_get_geometry_reply(c, xcb_get_geometry(c, pixmap), NULL);
  if (!r) {
    return false;
  }

  bool ret = r->width && r->height;
  free(r);
  return ret;
}
/// Names of root window properties that could point to a pixmap of
/// background.
static const char *background_props_str[] = {
  "_XROOTPMAP_ID",
  "_XSETROOT_ID",
  0,
};

xcb_pixmap_t x_get_root_back_pixmap(session_t *ps) {
  xcb_pixmap_t pixmap = XCB_NONE;

  // Get the values of background attributes
  for (int p = 0; background_props_str[p]; p++) {
    xcb_atom_t prop_atom = get_atom(ps, background_props_str[p]);
    winprop_t prop =
      wid_get_prop(ps, ps->root, prop_atom, 1, XCB_ATOM_PIXMAP, 32);
    if (prop.nitems) {
      pixmap = *prop.p32;
      free_winprop(&prop);
      break;
    }
    free_winprop(&prop);
  }

  return pixmap;
}

bool x_is_root_back_pixmap_atom(session_t *ps, xcb_atom_t atom) {
  for (int p = 0; background_props_str[p]; p++) {
    xcb_atom_t prop_atom = get_atom(ps, background_props_str[p]);
    if (prop_atom == atom)
      return true;
  }
  return false;
}

/**
 * Synchronizes a X Render drawable to ensure all pending painting requests
 * are completed.
 */
bool x_fence_sync(xcb_connection_t *c, xcb_sync_fence_t f) {
  // TODO(richardgv): If everybody just follows the rules stated in X Sync
  // prototype, we need only one fence per screen, but let's stay a bit
  // cautious right now

  auto e = xcb_request_check(c, xcb_sync_trigger_fence_checked(c, f));
  if (e) {
    log_error("Failed to trigger the fence.");
    free(e);
    return false;
  }

  e = xcb_request_check(c, xcb_sync_await_fence_checked(c, 1, &f));
  if (e) {
    log_error("Failed to await on a fence.");
    free(e);
    return false;
  }

  e = xcb_request_check(c, xcb_sync_reset_fence_checked(c, f));
  if (e) {
    log_error("Failed to reset the fence.");
    free(e);
    return false;
  }
  return true;
}

// xcb-render specific macros
#define XFIXED_TO_DOUBLE(value) (((double) (value)) / 65536)
#define DOUBLE_TO_XFIXED(value) ((xcb_render_fixed_t) (((double) (value)) * 65536))

/**
 * Set the picture filter of a xrender picture to a convolution
 * kernel.
 *
 * @param c   xcb connection
 * @param pict the picture
 * @param kern the convolution kernel
 */
void
x_set_picture_convolution_kernel(xcb_connection_t *c,
                                 xcb_render_picture_t pict, conv *kernel) {
  auto buf = ccalloc(kernel->w * kernel->h + 2, xcb_render_fixed_t);
  static const char *filter = "convolution";
  buf[0] = DOUBLE_TO_XFIXED(kernel->w);
  buf[1] = DOUBLE_TO_XFIXED(kernel->h);
  for (int i = 0; i < kernel->w * kernel->h; i++) {
    buf[i + 2] = DOUBLE_TO_XFIXED(kernel->data[i]);
  }
  xcb_render_set_picture_filter(c, pict, sizeof(filter), filter, kernel->w * kernel->h + 2, buf);
  free(buf);
}