/* GDK - The GIMP Drawing Kit
 * Copyright (C) 1995-1997 Peter Mattis, Spencer Kimball and Josh MacDonald
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 02111-1307, USA.
 */

/*
 * Modified by the GTK+ Team and others 1997-2000.  See the AUTHORS
 * file for a list of people on the GTK+ Team.  See the ChangeLog
 * files for a list of changes.  These files are distributed with
 * GTK+ at ftp://ftp.gtk.org/pub/gtk/. 
 */

#include <config.h>

#include <stdlib.h>
#include <sys/types.h>

#if defined (HAVE_IPC_H) && defined (HAVE_SHM_H) && defined (HAVE_XSHM_H)
#define USE_SHM
#endif

#ifdef USE_SHM
#include <sys/ipc.h>
#include <sys/shm.h>
#endif /* USE_SHM */

#include <X11/Xlib.h>
#include <X11/Xutil.h>

#ifdef USE_SHM
#include <X11/extensions/XShm.h>
#endif /* USE_SHM */

#include <errno.h>

#include "gdk.h"		/* For gdk_error_trap_* / gdk_flush_* */
#include "gdkimage.h"
#include "gdkprivate.h"
#include "gdkprivate-x11.h"

static GList *image_list = NULL;
static gpointer parent_class = NULL;

static void gdk_x11_image_destroy (GdkImage      *image);
static void gdk_image_init        (GdkImage      *image);
static void gdk_image_class_init  (GdkImageClass *klass);
static void gdk_image_finalize    (GObject       *object);

#define PRIVATE_DATA(image) ((GdkImagePrivateX11 *) GDK_IMAGE (image)->windowing_data)

GType
gdk_image_get_type (void)
{
  static GType object_type = 0;

  if (!object_type)
    {
      static const GTypeInfo object_info =
      {
        sizeof (GdkImageClass),
        (GBaseInitFunc) NULL,
        (GBaseFinalizeFunc) NULL,
        (GClassInitFunc) gdk_image_class_init,
        NULL,           /* class_finalize */
        NULL,           /* class_data */
        sizeof (GdkImage),
        0,              /* n_preallocs */
        (GInstanceInitFunc) gdk_image_init,
      };
      
      object_type = g_type_register_static (G_TYPE_OBJECT,
                                            "GdkImage",
                                            &object_info, 0);
    }
  
  return object_type;
}

static void
gdk_image_init (GdkImage *image)
{
  image->windowing_data = g_new0 (GdkImagePrivateX11, 1);
}

static void
gdk_image_class_init (GdkImageClass *klass)
{
  GObjectClass *object_class = G_OBJECT_CLASS (klass);

  parent_class = g_type_class_peek_parent (klass);

  object_class->finalize = gdk_image_finalize;
}

static void
gdk_image_finalize (GObject *object)
{
  GdkImage *image = GDK_IMAGE (object);

  gdk_x11_image_destroy (image);
  
  G_OBJECT_CLASS (parent_class)->finalize (object);
}


void
gdk_image_exit (void)
{
  GdkImage *image;

  while (image_list)
    {
      image = image_list->data;
      gdk_x11_image_destroy (image);
    }
}

GdkImage *
gdk_image_new_bitmap(GdkVisual *visual, gpointer data, gint w, gint h)
/*
 * Desc: create a new bitmap image
 */
{
  Visual *xvisual;
  GdkImage *image;
  GdkImagePrivateX11 *private;
  image = g_object_new (gdk_image_get_type (), NULL);
  private = PRIVATE_DATA (image);
  private->xdisplay = gdk_display;
  image->type = GDK_IMAGE_NORMAL;
  image->visual = visual;
  image->width = w;
  image->height = h;
  image->depth = 1;
  image->bits_per_pixel = 1;
  xvisual = ((GdkVisualPrivate*) visual)->xvisual;
  private->ximage = XCreateImage(private->xdisplay, xvisual, 1, XYBitmap,
				 0, 0, w ,h, 8, 0);
  private->ximage->data = data;
  private->ximage->bitmap_bit_order = MSBFirst;
  private->ximage->byte_order = MSBFirst;
  image->byte_order = MSBFirst;
  image->mem =  private->ximage->data;
  image->bpl = private->ximage->bytes_per_line;
  image->bpp = 1;
  return(image);
} /* gdk_image_new_bitmap() */

static int
gdk_image_check_xshm(Display *display)
/* 
 * Desc: query the server for support for the MIT_SHM extension
 * Return:  0 = not available
 *          1 = shared XImage support available
 *          2 = shared Pixmap support available also
 */
{
#ifdef USE_SHM
  int major, minor, ignore;
  Bool pixmaps;
  
  if (XQueryExtension(display, "MIT-SHM", &ignore, &ignore, &ignore)) 
    {
      if (XShmQueryVersion(display, &major, &minor, &pixmaps )==True) 
	{
	  return (pixmaps==True) ? 2 : 1;
	}
    }
#endif /* USE_SHM */
  return 0;
}

void
_gdk_windowing_image_init (void)
{
  if (gdk_use_xshm)
    {
      if (!gdk_image_check_xshm (gdk_display))
	{
	  gdk_use_xshm = False;
	}
    }
}

GdkImage*
gdk_image_new (GdkImageType  type,
	       GdkVisual    *visual,
	       gint          width,
	       gint          height)
{
  GdkImage *image;
  GdkImagePrivateX11 *private;
#ifdef USE_SHM
  XShmSegmentInfo *x_shm_info;
#endif /* USE_SHM */
  Visual *xvisual;

  switch (type)
    {
    case GDK_IMAGE_FASTEST:
      image = gdk_image_new (GDK_IMAGE_SHARED, visual, width, height);

      if (!image)
	image = gdk_image_new (GDK_IMAGE_NORMAL, visual, width, height);
      break;

    default:
      image = g_object_new (gdk_image_get_type (), NULL);
      
      private = PRIVATE_DATA (image);

      private->xdisplay = gdk_display;

      image->type = type;
      image->visual = visual;
      image->width = width;
      image->height = height;
      image->depth = visual->depth;

      xvisual = ((GdkVisualPrivate*) visual)->xvisual;

      switch (type)
	{
	case GDK_IMAGE_SHARED:
#ifdef USE_SHM
	  if (gdk_use_xshm)
	    {
	      private->x_shm_info = g_new (XShmSegmentInfo, 1);
	      x_shm_info = private->x_shm_info;
	      x_shm_info->shmid = -1;
	      x_shm_info->shmaddr = (char*) -1;

	      private->ximage = XShmCreateImage (private->xdisplay, xvisual, visual->depth,
						 ZPixmap, NULL, x_shm_info, width, height);
	      if (private->ximage == NULL)
		{
		  g_warning ("XShmCreateImage failed");
		  gdk_use_xshm = FALSE;

		  goto error;
		}

	      x_shm_info->shmid = shmget (IPC_PRIVATE,
					  private->ximage->bytes_per_line * private->ximage->height,
					  IPC_CREAT | 0600);

	      if (x_shm_info->shmid == -1)
		{
		  /* EINVAL indicates, most likely, that the segment we asked for
		   * is bigger than SHMMAX, so we don't treat it as a permanent
		   * error. ENOSPC and ENOMEM may also indicate this, but
		   * more likely are permanent errors.
		   */
		  if (errno != EINVAL)
		    {
		      g_warning ("shmget failed: error %d (%s)", errno, g_strerror (errno));
		      gdk_use_xshm = FALSE;
		    }

		  goto error;
		}

	      x_shm_info->readOnly = False;
	      x_shm_info->shmaddr = shmat (x_shm_info->shmid, 0, 0);
	      private->ximage->data = x_shm_info->shmaddr;

	      if (x_shm_info->shmaddr == (char*) -1)
		{
		  g_warning ("shmat failed: error %d (%s)", errno, g_strerror (errno));
		  /* Failure in shmat is almost certainly permanent. Most likely error is
		   * EMFILE, which would mean that we've exceeded the per-process
		   * Shm segment limit.
		   */
		  gdk_use_xshm = FALSE;
		  goto error;
		}

	      gdk_error_trap_push ();

	      XShmAttach (private->xdisplay, x_shm_info);
	      XSync (private->xdisplay, False);

	      if (gdk_error_trap_pop ())
		{
		  /* this is the common failure case so omit warning */
		  gdk_use_xshm = FALSE;
		  goto error;
		}
	      
	      /* We mark the segment as destroyed so that when
	       * the last process detaches, it will be deleted.
	       * There is a small possibility of leaking if
	       * we die in XShmAttach. In theory, a signal handler
	       * could be set up.
	       */
	      shmctl (x_shm_info->shmid, IPC_RMID, 0);		      

	      if (image)
		image_list = g_list_prepend (image_list, image);
	    }
	  else
#endif /* USE_SHM */
	    goto error;
	  break;
	case GDK_IMAGE_NORMAL:
	  private->ximage = XCreateImage (private->xdisplay, xvisual, visual->depth,
					  ZPixmap, 0, 0, width, height, 32, 0);

	  /* Use malloc, not g_malloc here, because X will call free()
	   * on this data
	   */
	  private->ximage->data = malloc (private->ximage->bytes_per_line *
					  private->ximage->height);
	  if (!private->ximage->data)
	    goto error;
	  break;

	case GDK_IMAGE_FASTEST:
	  g_assert_not_reached ();
	}

      if (image)
	{
	  image->byte_order = private->ximage->byte_order;
	  image->mem = private->ximage->data;
	  image->bpl = private->ximage->bytes_per_line;
	  image->bpp = (private->ximage->bits_per_pixel + 7) / 8;
	  image->bits_per_pixel = private->ximage->bits_per_pixel;
	}
    }

  return image;

 error:
  if (private->ximage)
    {
      XDestroyImage (private->ximage);
      private->ximage = NULL;
    }
#ifdef USE_SHM
  if (private->x_shm_info)
    {
      x_shm_info = private->x_shm_info;
      
      if (x_shm_info->shmaddr != (char *)-1)
	shmdt (x_shm_info->shmaddr);
      if (x_shm_info->shmid != -1) 
	shmctl (x_shm_info->shmid, IPC_RMID, 0);
      
      g_free (x_shm_info);
      private->x_shm_info = NULL;
    }
#endif /* USE_SHM */
  g_object_unref (image);
  
  return NULL;
}

GdkImage*
_gdk_x11_get_image (GdkDrawable    *drawable,
                    gint            x,
                    gint            y,
                    gint            width,
                    gint            height)
{
  GdkImage *image;
  GdkImagePrivateX11 *private;
  GdkDrawableImplX11 *impl;
  GdkVisual *visual;
  gboolean have_grab;
  GdkRectangle req;
  GdkRectangle window_rect;
  XImage *ximage;
  
  g_return_val_if_fail (GDK_IS_DRAWABLE_IMPL_X11 (drawable), NULL);

  visual = gdk_drawable_get_visual (drawable);

  g_assert (visual || !GDK_IS_WINDOW (drawable));

  impl = GDK_DRAWABLE_IMPL_X11 (drawable);
  
  have_grab = FALSE;

  if (GDK_IS_WINDOW (drawable))
    {
      GdkRectangle screen_rect;
      Window child;

      g_assert (visual);
      
      have_grab = TRUE;
      gdk_x11_grab_server ();
      
      XTranslateCoordinates (GDK_DRAWABLE_XDISPLAY (drawable),
			     gdk_root_window,
			     GDK_DRAWABLE_XID (drawable),
			     0, 0, 
			     &screen_rect.x, &screen_rect.y, 
			     &child);

      screen_rect.width = gdk_screen_width ();
      screen_rect.height = gdk_screen_height ();
      
      gdk_error_trap_push ();
      
      gdk_window_get_geometry (GDK_WINDOW (drawable),
                               &window_rect.x,
                               &window_rect.y,
                               &window_rect.width,
                               &window_rect.height,
                               NULL);

      if (gdk_error_trap_pop () ||
          !gdk_rectangle_intersect (&window_rect, &screen_rect, 
                                    &window_rect))
        {
          gdk_x11_ungrab_server ();
          return image = gdk_image_new (GDK_IMAGE_FASTEST,
                                        visual,
                                        width, height);
        }
    }
  else
    {
      window_rect.x = 0;
      window_rect.y = 0;
      gdk_drawable_get_size (drawable,
			     &window_rect.width,
			     &window_rect.height);
    }
      
  req.x = x;
  req.y = y;
  req.width = width;
  req.height = height;
  
  /* window_rect specifies the part of drawable which we can get from
     the server in window coordinates. 
     For pixmaps this is all of the pixmap, for windows it is just 
     the onscreen part. */
  if (!gdk_rectangle_intersect (&req, &window_rect, &req) && visual) 
    {
      if (have_grab)
	gdk_x11_ungrab_server ();
      return image = gdk_image_new (GDK_IMAGE_FASTEST,
                                    visual,
                                    width, height);
    }

  if (req.x != x || req.y != y)
    {
      g_assert (GDK_IS_WINDOW (drawable));
      g_assert (visual);

      image = gdk_image_new (GDK_IMAGE_FASTEST,
                             visual,
                             width, height);
      if (image == NULL)
        return NULL;

      private = PRIVATE_DATA (image);

      gdk_error_trap_push ();

      ximage = XGetSubImage (impl->xdisplay,
                             impl->xid,
                             req.x, req.y, req.width, req.height,
                             AllPlanes, ZPixmap,
                             private->ximage,
                             req.x - x, req.y - y);

      if (have_grab)
        gdk_x11_ungrab_server ();
      
      if (gdk_error_trap_pop () || ximage == NULL)
        {
          g_object_unref (G_OBJECT (image));
          return NULL;
        }

      g_assert (ximage == private->ximage);
    }
  else
    {

      ximage = XGetImage (impl->xdisplay,
                          impl->xid,
                          x, y, width, height,
                          AllPlanes, ZPixmap);

      if (!ximage)
        {
          if (have_grab)
            gdk_x11_ungrab_server ();
          return NULL;
        }

      image = g_object_new (gdk_image_get_type (), NULL);

      private = PRIVATE_DATA (image);

      private->xdisplay = gdk_display;
      private->ximage = ximage;

      image->type = GDK_IMAGE_NORMAL;
      image->visual = visual; /* May be NULL */
      image->width = width;
      image->height = height;
      image->depth = gdk_drawable_get_depth (drawable);

      image->mem = private->ximage->data;
      image->bpl = private->ximage->bytes_per_line;
      image->bits_per_pixel = private->ximage->bits_per_pixel;
      image->bpp = (private->ximage->bits_per_pixel + 7) / 8;
      image->byte_order = private->ximage->byte_order; 
    }

  return image;
}

guint32
gdk_image_get_pixel (GdkImage *image,
		     gint x,
		     gint y)
{
  guint32 pixel;
  GdkImagePrivateX11 *private;

  g_return_val_if_fail (GDK_IS_IMAGE (image), 0);

  private = PRIVATE_DATA (image);

  pixel = XGetPixel (private->ximage, x, y);

  return pixel;
}

void
gdk_image_put_pixel (GdkImage *image,
		     gint x,
		     gint y,
		     guint32 pixel)
{
  GdkImagePrivateX11 *private;

  g_return_if_fail (GDK_IS_IMAGE (image));

  private = PRIVATE_DATA (image);

  pixel = XPutPixel (private->ximage, x, y, pixel);
}

static void
gdk_x11_image_destroy (GdkImage *image)
{
  GdkImagePrivateX11 *private;
#ifdef USE_SHM
  XShmSegmentInfo *x_shm_info;
#endif /* USE_SHM */

  g_return_if_fail (GDK_IS_IMAGE (image));

  private = PRIVATE_DATA (image);

  if (private == NULL) /* This means that gdk_image_exit() destroyed the
                        * image already, and now we're called a second
                        * time from _finalize()
                        */
    return;

  if (private->ximage)		/* Deal with failure of creation */
    {
      switch (image->type)
	{
	case GDK_IMAGE_NORMAL:
	  XDestroyImage (private->ximage);
	  break;
	  
	case GDK_IMAGE_SHARED:
#ifdef USE_SHM
	  gdk_flush();
	  
	  XShmDetach (private->xdisplay, private->x_shm_info);
	  XDestroyImage (private->ximage);
	  
	  x_shm_info = private->x_shm_info;
	  shmdt (x_shm_info->shmaddr);
	  
	  g_free (private->x_shm_info);
	  private->x_shm_info = NULL;
	  
	  image_list = g_list_remove (image_list, image);
#else /* USE_SHM */
	  g_error ("trying to destroy shared memory image when gdk was compiled without shared memory support");
#endif /* USE_SHM */
	  break;
	  
	case GDK_IMAGE_FASTEST:
	  g_assert_not_reached ();
	}
    }

  g_free (private);
  image->windowing_data = NULL;
}