firefox/testing/tools/screenshot/gdk-screenshot.cpp

/*
 * Copyright (c) 2009, The Mozilla Foundation
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in the
 *       documentation and/or other materials provided with the distribution.
 *     * Neither the name of the Mozilla Foundation nor the
 *       names of its contributors may be used to endorse or promote products
 *       derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY The Mozilla Foundation ''AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL The Mozilla Foundation BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * Contributors:
 *   Ted Mielczarek <ted.mielczarek@gmail.com>
 *   Karl Tomlinson <karlt+@karlt.net>
 */
/*
 * gdk-screenshot.cpp: Save a screenshot of the root window in .png format.
 *  If a filename is specified as the first argument on the commandline,
 *  then the image will be saved to that filename. Otherwise, the image will
 *  be written to stdout.
 */
#include <gdk/gdk.h>
#ifdef MOZ_WAYLAND
#  include <gdk/gdkwayland.h>
#  include "mozilla/GUniquePtr.h"
#  include "mozilla/UniquePtrExtensions.h"
#  include "mozilla/ScopeExit.h"
#endif

#include <errno.h>
#include <stdio.h>
#include <unistd.h>

gboolean save_to_stdout(const gchar* buf, gsize count, GError** error,
                        gpointer data) {
  size_t written = fwrite(buf, 1, count, stdout);
  if (written != count) {
    g_set_error(error, G_FILE_ERROR, g_file_error_from_errno(errno),
                "Write to stdout failed: %s", g_strerror(errno));
    return FALSE;
  }

  return TRUE;
}

#if defined(MOZ_WAYLAND)
static GdkPixbuf* get_screenshot_gnome(char* aAppName) {
  char* path =
      g_build_filename(g_get_user_cache_dir(), "mozilla-screenshot", nullptr);
  g_mkdir_with_parents(path, 0700);
  char* tmpname = g_strdup_printf("mozilla-screen-%d.png", g_random_int());
  char* filename = g_build_filename(path, tmpname, nullptr);

  auto autoFree = mozilla::MakeScopeExit([&] {
    unlink(filename);
    g_free(path);
    g_free(tmpname);
    g_free(filename);
  });

  mozilla::GUniquePtr<GError> error;
  char* argv[] = {g_strdup("/usr/bin/gnome-screenshot"), g_strdup("-f"),
                  filename, nullptr};
  gboolean ret = g_spawn_sync(
      nullptr, argv, nullptr, GSpawnFlags(G_SPAWN_LEAVE_DESCRIPTORS_OPEN),
      nullptr, nullptr, nullptr, nullptr, nullptr, getter_Transfers(error));
  if (!ret || error) {
    fprintf(stderr, "%s: g_spawn_sync() of gnome-screenshot failed: %s\n",
            aAppName, error ? error->message : "");
    return nullptr;
  }

  GdkPixbuf* screenshot = gdk_pixbuf_new_from_file(filename, nullptr);
  if (!screenshot) {
    fprintf(stderr, "%s: gdk_pixbuf_new_from_file %s failed\n", aAppName,
            filename);
  }
  return screenshot;
}
#endif

int main(int argc, char** argv) {
  gdk_init(&argc, &argv);

  GdkPixbuf* screenshot = nullptr;

#if defined(MOZ_WAYLAND)
  GdkDisplay* display = gdk_display_get_default();
  if (display && GDK_IS_WAYLAND_DISPLAY(display)) {
    screenshot = get_screenshot_gnome(argv[0]);
    if (!screenshot) {
      fprintf(stderr, "%s: failed to create screenshot Wayland/GdkPixbuf\n",
              argv[0]);
      return 1;
    }
  }
#endif
  if (!screenshot) {
    GdkWindow* window = gdk_get_default_root_window();
    screenshot =
        gdk_pixbuf_get_from_window(window, 0, 0, gdk_window_get_width(window),
                                   gdk_window_get_height(window));
    if (!screenshot) {
      fprintf(stderr, "%s: failed to create screenshot X11/GdkPixbuf\n",
              argv[0]);
      return 1;
    }
  }

  GError* error = nullptr;
  if (argc > 1) {
    gdk_pixbuf_save(screenshot, argv[1], "png", &error, nullptr);
  } else {
    gdk_pixbuf_save_to_callback(screenshot, save_to_stdout, nullptr, "png",
                                &error, nullptr);
  }
  if (error) {
    fprintf(stderr, "%s: failed to write screenshot as png: %s\n", argv[0],
            error->message);
    return error->code;
  }

  return 0;
}