Incorporated Adam's copy-on-write patches. Seems to not break anything,

Incorporated Adam's copy-on-write patches.  Seems to not break
anything, but I'm sure they do somewhere. --sg

ChangeLog

+Thu Jul  2 18:10:43 1998  Scott Goehring  <scott@poverty.bloomington.in.us>
+
+	* blend.c boundary.c by_color_select.c channel.c color_picker.c
+	drawable_cmds.c frac.c fuzzy_select.c image_render.c invert.c
+	layer.c paint_core.c paint_funcs.c pixel_region.c plug_in.c tile.c
+	tile.h tile_cache.c tile_manager.c transform_core.c undo.c xcf.c:
+	incorporated Adam's copy-on-write patches.  Tested briefly:
+	nothing seems to be broken, but I guarantee nothing.
+
 Thu Jul  2 11:03:12 PDT 1998 Manish Singh <yosh@gimp.org>
 
 	* updated blur, randomize, and exchange plugins (not sure if
@@ -358,7 +367,6 @@ Sat Jun 20 11:36:16 PDT 1998 Manish Singh <yosh@gimp.org>
 	* configure.in
 	* app/Makefile.am: really add thread support
 
->>>>>>> 1.454
 Sat Jun 20 12:04:41 1998  Scott Goehring  <scott@poverty.bloomington.in.us>
 
 	* app/tile.h: #include config.h so we can tell if we're doing
@@ -393,7 +401,6 @@ Fri Jun 19 12:34:29 PDT 1998 Manish Singh <yosh@gimp.org>
 	* changes libgimp versioning to gtk-style. Bunch o' Makefile.am
 	changes for that
 
->>>>>>> 1.430
 Thu Jun 18 23:11:36 1998  Owen Taylor  <otaylor@gtk.org>
 
 	* app/ink.c: Shift the range to smaller brushes.

app/actions/plug-in-commands.c

@@ -1360,7 +1360,7 @@ plug_in_handle_tile_req (GPTileReq *tile_req)
 	  return;
 	}
 
-      tile_ref (tile);
+      tile_ref2 (tile, TRUE);
 
       if (tile_data.use_shm)
 	memcpy (tile->data, shm_addr, tile_size (tile));
@@ -1407,7 +1407,7 @@ plug_in_handle_tile_req (GPTileReq *tile_req)
       tile_data.height = tile->eheight;
       tile_data.use_shm = (shm_ID == -1) ? FALSE : TRUE;
 
-      tile_ref (tile);
+      tile_ref2 (tile, FALSE);
 
       if (tile_data.use_shm)
 	memcpy (shm_addr, tile->data, tile_size (tile));

app/base/boundary.c

@@ -124,7 +124,7 @@ find_empty_segs (PixelRegion  *maskPR,
 	  if (tile)
 	    tile_unref (tile, FALSE);
 	  tile = tile_manager_get_tile (maskPR->tiles, x, scanline, 0);
-	  tile_ref (tile);
+	  tile_ref2 (tile, FALSE);
 	  data = tile->data + tile->bpp *
 	    ((scanline % TILE_HEIGHT) * tile->ewidth + (x % TILE_WIDTH)) + (tile->bpp - 1);
 	  tilex = x / TILE_WIDTH;

app/base/pixel-region.c

@@ -124,7 +124,7 @@ pixel_region_get_row (PR, x, y, w, data, subsample)
   while (x < end)
     {
       tile = tile_manager_get_tile (PR->tiles, x, y, 0);
-      tile_ref (tile);
+      tile_ref2 (tile, FALSE);
       tile_data = tile->data + tile->bpp * (tile->ewidth * (y % TILE_HEIGHT) + (x % TILE_WIDTH));
       boundary = x + (tile->ewidth - (x % TILE_WIDTH));
       inc = subsample * tile->bpp;
@@ -159,7 +159,7 @@ pixel_region_set_row (PR, x, y, w, data)
   while (x < end)
     {
       tile = tile_manager_get_tile (PR->tiles, x, y, 0);
-      tile_ref (tile);
+      tile_ref2 (tile, TRUE);
       tile_data = tile->data + tile->bpp * (tile->ewidth * (y % TILE_HEIGHT) + (x % TILE_WIDTH));
       boundary = x + (tile->ewidth - (x % TILE_WIDTH));
 
@@ -194,7 +194,7 @@ pixel_region_get_col (PR, x, y, h, data, subsample)
   while (y < end)
     {
       tile = tile_manager_get_tile (PR->tiles, x, y, 0);
-      tile_ref (tile);
+      tile_ref2 (tile, FALSE);
       tile_data = tile->data + tile->bpp * (tile->ewidth * (y % TILE_HEIGHT) + (x % TILE_WIDTH));
       boundary = y + (tile->eheight - (y % TILE_HEIGHT));
       inc = subsample * tile->bpp * tile->ewidth;
@@ -230,7 +230,7 @@ pixel_region_set_col (PR, x, y, h, data)
   while (y < end)
     {
       tile = tile_manager_get_tile (PR->tiles, x, y, 0);
-      tile_ref (tile);
+      tile_ref2 (tile, TRUE);
       tile_data = tile->data + tile->bpp * (tile->ewidth * (y % TILE_HEIGHT) + (x % TILE_WIDTH));
       boundary = y + (tile->eheight - (y % TILE_HEIGHT));
       inc = tile->bpp * tile->ewidth;
@@ -550,7 +550,7 @@ pixel_region_configure (PRH, PRI)
       int offx, offy;
 
       tile = tile_manager_get_tile (PRH->PR->tiles, PRH->PR->x, PRH->PR->y, 0);
-      tile_ref (tile);
+      tile_ref2 (tile, PRH->PR->dirty);
 
       offx = PRH->PR->x % TILE_WIDTH;
       offy = PRH->PR->y % TILE_HEIGHT;

app/base/tile-cache.c

 #include <gtk/gtkmain.h>
 #include <glib.h>
 #include "gimprc.h"
+#include "tile.h"
 #include "tile_cache.h"
 #include "tile_swap.h"
 #ifdef USE_PTHREADS

app/base/tile-manager.c

@@ -339,8 +339,8 @@ tile_manager_update_tile (TileManager *tm,
 
   tile = tile_manager_get (tm, num, level);
 
-  tile_ref (tile);
-  tile_ref (toplevel_tile);
+  tile_ref2 (tile, TRUE);
+  tile_ref2 (toplevel_tile, FALSE);
 
   tilew += tilex;
   tileh += tiley;

app/base/tile.c

+#include <stdio.h>
+
 #include "tile.h"
 #include "tile_cache.h"
 #include "tile_manager.h"
 #include "tile_swap.h"
 
+/* EXPERIMENTAL Copy-On-Write goodies
+ *  by Adam D. Moss
+ *   adam@gimp.org
+ *   adam@foxbox.org
+ *
+ *
+ * C.O.W. Revisions:
+ *
+ *   97.10.05 - Initial release
+ *   97.10.06 - Much faster tile invalidation +
+ *              Better swap interaction (should no longer
+ *                crash GIMP when GIMP swapfile is full).
+ *   97.10.18 - Very stable now, and even more efficient.
+ *   98.06.16 - Revised from GIMP 0.99.14 for 1.[01].0 - no
+ *                longer so sure about stability until
+ *                more comprehensive testing is done.
+ *
+ *
+ * MISC TODO:
+ *
+ *  tile_invalidate: (tile_manager) - don't let a tile become
+ *   invalidated if its ref-count >1, but move it to a delete-on-last-unref
+ *   list instead...
+ */
+
+/*
+ * Define MUCH_TILE_DEBUG in addition to TILE_DEBUG to get
+ * debugging for every single tile_ref2 and tile_unref (that's
+ * a lot).
+#define MUCH_TILE_DEBUG heckyeah
+*/
+
+
 
 void
 tile_init (Tile *tile,
@@ -11,11 +46,13 @@ tile_init (Tile *tile,
   tile->ref_count = 0;
   tile->dirty = FALSE;
   tile->valid = FALSE;
+  tile->data = NULL;
+  tile->real_tile_ptr = NULL;
+  tile->mirrored_by = NULL;
   tile->ewidth = TILE_WIDTH;
   tile->eheight = TILE_HEIGHT;
   tile->bpp = bpp;
   tile->tile_num = -1;
-  tile->data = NULL;
   tile->swap_num = 1;
   tile->swap_offset = -1;
   tile->tm = NULL;
@@ -28,57 +65,417 @@ tile_init (Tile *tile,
 #endif
 }
 
+
+
 int tile_ref_count = 0;
 
+
 void
 #if defined (TILE_DEBUG) && defined (__GNUC__)
 _tile_ref (Tile *tile, char *func_name)
 #else
 tile_ref (Tile *tile)
 #endif
+{
+  /* While things get moved over to the new tile_ref2
+   * interface, tile_ref is a wrapper which just says
+   * 'yes, we'll be dirtying the tile'
+   */
+
+#if defined (TILE_DEBUG) && defined (__GNUC__)
+  printf("COW-Warning: function %s is using obsolete tile_ref interface\n",
+	 func_name);
+#endif
+
+#if defined (TILE_DEBUG) && defined (__GNUC__)
+  _tile_ref2 (tile, TRUE, func_name);
+#else
+  tile_ref2 (tile, TRUE);
+#endif
+}
+
+
+gboolean
+tile_is_mirroring (Tile *tile)
+{
+  return (tile->real_tile_ptr != NULL);
+}
+
+
+gboolean
+tile_is_mirrored (Tile *tile)
+{
+  return (tile->mirrored_by != NULL);
+}
+
+
+gboolean
+tile_is_real (Tile *tile)
+{
+  return (tile->real_tile_ptr == NULL);
+}
+
+
+/* Follow the real_tile_ptr links back to the tile which provides
+ *  the real source data for the given tile
+ */
+Tile *
+tile_find_nonmirroring (Tile *tile)
+{
+  if (! tile_is_mirroring (tile))
+    {
+      return tile;
+    }
+  else
+    {
+      return tile_find_nonmirroring (tile->real_tile_ptr);
+    }
+}
+
+
+/* 
+ */
+Tile *
+tile_find_finalmirroring (Tile *tile)
+{
+  if (! tile_is_mirrored (tile))
+    {
+      return tile;
+    }
+  else
+    {
+      return tile_find_finalmirroring (tile->mirrored_by);
+    }
+}
+
+
+/* Take a mirroring-tile and turn it into a bona fide self-contained
+ *  tile.
+ */
+void
+tile_devirtualize (Tile *tile)
+{
+  Tile *real_tile;
+
+  /* Sanity */
+  if (tile_is_real (tile))
+    g_error ("Tried to devirtualize a real tile");
+#if defined (TILE_DEBUG)
+  if (tile->ref_count == 0)
+    g_warning ("Trying to devirtualize a mirroring-tile with no ref_count");
+#endif
+
+  /* Go find the tile ('real_tile') which owns the real data
+   */
+  real_tile = tile_find_nonmirroring (tile);
+
+  /* Sanity */
+#if defined (TILE_DEBUG)
+  if (real_tile->ref_count == 0)
+    g_warning ("Trying to devirtualize a mirroring-tile whose real_tile has no ref_count");
+#endif
+  if (!real_tile->valid)
+    g_warning ("Trying to devirtualize a mirroring-tile whose real_tile is !valid");
+
+  /* Copy the actual tile data from the real_tile to this tile
+   */
+  tile->data = NULL;
+  tile_alloc (tile);
+/*  printf ("{ %dx%d : %d  - %p[%p]->%p[%p] }", real_tile->ewidth, real_tile->eheight,
+	  real_tile->bpp, real_tile, real_tile->data, tile, tile->data);
+  fflush(stdout);*/
+
+  memcpy (tile->data, real_tile->data, tile_size(real_tile));
+
+  /* 'tile' is now a real tile. */
+  tile->real_tile_ptr = NULL;
+  tile->valid = TRUE;
+
+  tile_cache_insert(tile);
+
+#if defined (TILE_DEBUG)
+  g_print ("Tile at %p is now devirtualized.\n", tile);
+#endif
+}
+
+
+/* Make this tile self-contained.  
+ *
+ * The next tile in the linked-list of tiles which are mirroring 'tile'
+ *  is promoted to a real physical tile and unlinked from 'tile'.  This
+ *  renders 'tile' safe for dirtying (or destruction).
+ */
+void
+tile_isolate (Tile *tile)
+{
+  Tile *temp_tileptr;
+
+  /* Sanity
+   */
+  if (! (tile_is_mirrored (tile) || tile_is_mirroring (tile)))
+    {
+      g_warning ("Tried to isolate a tile which is neither a mirror source "
+		 "nor destination");
+      return;
+    }
+
+  /* This tile is both linked to and linked from? */
+  if (tile_is_mirrored (tile) && tile_is_mirroring (tile))
+    {
+      temp_tileptr = tile->real_tile_ptr;
+
+#if defined (TILE_DEBUG)
+      g_print ("tile %p: was middle of chain - relinking %p and %p\n",
+	       tile,
+	       temp_tileptr,
+	       tile->mirrored_by);
+#endif
+
+      tile->mirrored_by->real_tile_ptr = temp_tileptr;
+      temp_tileptr->mirrored_by = tile->mirrored_by;
+      
+      tile_ref2 (temp_tileptr, FALSE);
+      tile_devirtualize (tile);
+      tile_unref (temp_tileptr, FALSE);
+
+      tile->mirrored_by = NULL;
+
+      return;
+    }
+
+  /* This tile is mirroring another, but is not mirrored itself? */
+  if (tile_is_mirroring (tile))
+    {
+      temp_tileptr = tile->real_tile_ptr;
+
+#if defined (TILE_DEBUG)
+      g_print ("tile %p: was end of chain - cauterizing %p\n",
+	       tile,
+	       temp_tileptr);
+#endif
+
+      /* We stop mirroring the tile which we previously were -
+       *  so reset that tile's mirrored_by pointer.
+       */
+      temp_tileptr->mirrored_by = NULL;
+
+      tile_ref2 (temp_tileptr, FALSE);
+      tile_devirtualize (tile);
+      tile_unref (temp_tileptr, FALSE);
+
+      return;
+    }
+
+  /* This tile is mirrored by another, but is not itself a mirror. */
+  if (tile_is_mirrored (tile))
+    {
+#if defined (TILE_DEBUG)
+      g_print ("tile %p: was source of chain - devirtualizing %p\n",
+	       tile,
+	       tile->mirrored_by);
+#endif
+
+     temp_tileptr = tile->mirrored_by;
+
+      tile_ref2 (temp_tileptr, FALSE);
+      tile_devirtualize (temp_tileptr);
+      tile_unref (temp_tileptr, FALSE);
+
+      /* The tile which was dependant on this one no longer is -
+       *  so we can unref once.
+       */
+      tile_unref (tile, FALSE);
+
+      tile->mirrored_by = NULL;
+
+      return;
+    }
+}
+
+
+/* Turns dest_tile into a mirroring-tile which mirrors the given
+ *  src_tile using copy-on-write.
+ */
+void
+tile_mirror (Tile *dest_tile, Tile *src_tile)
+{
+  Tile *finalmirroring;
+
+  if (dest_tile == src_tile)
+    {
+      g_warning ("TRIED TO MIRROR TILE TO ITSELF");
+      return;
+    }
+
+#if defined (TILE_DEBUG)
+  g_print ("mirroring "); 
+#endif
+
+  if (tile_is_real (dest_tile))
+    {
+#if defined (TILE_DEBUG)
+      g_print ("TO REAL ");   
+#endif
+      tile_invalidate (dest_tile);
+    }
+  else
+    {
+      tile_invalidate (dest_tile);
+    }
+
+  /*      dest_tile->ref_count = 0; */
+  dest_tile->dirty = FALSE;
+  dest_tile->valid = FALSE;
+  dest_tile->data = NULL;
+  dest_tile->ewidth = src_tile->ewidth;
+  dest_tile->eheight = src_tile->eheight;
+  dest_tile->bpp = src_tile->bpp;
+  dest_tile->tile_num = -1; /* ! */
+
+  /* 
+   */
+  finalmirroring = tile_find_finalmirroring (src_tile);
+  dest_tile->real_tile_ptr = finalmirroring;
+  finalmirroring->mirrored_by = dest_tile;
+  
+#if defined (TILE_DEBUG)
+  g_print ("%p -> %p\n", finalmirroring, dest_tile);
+#endif
+
+  /* The following should be irrelevant in a mirroring tile - mirroring
+   *  tiles by definition don't have real data of their own, so they can't
+   *  be swapped.  They don't have associated TileManagers either, since they
+   *  rely on their mirrored source tile to contain validated data.
+   */
+  dest_tile->swap_num = 1;
+  dest_tile->swap_offset = -1;
+  dest_tile->tm = NULL;
+}
+
+
+void
+#if defined (TILE_DEBUG) && defined (__GNUC__)
+_tile_ref2 (Tile *tile, int dirty, char *func_name)
+#else
+tile_ref2 (Tile *tile, int dirty)
+#endif
 {
 #ifdef USE_PTHREADS
   pthread_mutex_lock(&(tile->mutex));
 #endif
-  /*  g_print ("tile_ref:    0x%08x  %s\n", tile, func_name); */
+#if defined (TILE_DEBUG) && defined (__GNUC__) && defined (MUCH_TILE_DEBUG)
+  g_print ("tile_ref2:   %02d  %c  %p  %s\n", tile->ref_count,
+	   dirty?'d':' ',
+	   tile,
+	   func_name);
+#endif
+
+  /*g_print ("tile_ref2:   %02d  %c  %p\n", tile->ref_count,
+	   dirty?'d':' ',
+	   tile);*/
 
+
+
+  /* Increment the global reference count.
+   */
   tile_ref_count += 1;
 
-  /* Increment the reference count.
+  /* Increment this tile's reference count.
    */
   tile->ref_count += 1;
 
-  /* If this is the first reference to the tile then
-   *  swap the tile data in from disk. Note: this will
-   *  properly handle the case where the tile data isn't
-   *  on disk.
+#if defined (TILE_DEBUG)
+  if (tile_is_mirrored (tile) && dirty)
+    {
+      g_print ("Dirtying a mirrored tile: %p.\n", tile);
+    }
+#endif
+
+/*
+  if (dirty && tile->dirty)
+    {
+      g_print ("Not good: Dirtying a write-locked tile: %p.\n", tile);
+    } */
+
+
+  /* if this is a read-only attachment to a mirroring tile,
+   *  then ref the chain, update the data pointer, and return.
    */
-  if (tile->ref_count == 1)
+  if ((!dirty) && (tile_is_mirroring (tile)))
     {
-      tile_swap_in (tile);
+      /* ref each of the tiles in the chain, back to the
+       *  'real' tile which sits at the start.
+       */
+#if USE_PTHREADS
+      pthread_mutex_unlock(&(tile->mutex));
+#endif
+      tile_ref2 (tile->real_tile_ptr, FALSE);
+      tile->data = tile->real_tile_ptr->data;
+      return;
+    }
+
+
+  /* dirty, or clean-and-real */
 
-      /*  the tile must be clean  */
-      tile->dirty = FALSE;
+
+  /* Real tile - first reference. */
+  if (!tile_is_mirroring (tile))
+    {
+      /* If this is the first reference to the tile then
+       *  swap the tile data in from disk. Note: this will
+       *  properly handle the case where the tile data isn't
+       *  on disk.
+       */
+      if (tile->ref_count == 1)
+	{
+	  tile_swap_in (tile);
+	}
+      
+      /* Insert the tile into the cache. If the tile is already
+       *  in the cache this will have the affect of "touching"
+       *  the tile.
+       */
+      tile_cache_insert (tile);
     }
 
-  /* Insert the tile into the cache. If the tile is already
-   *  in the cache this will have the affect of "touching"
-   *  the tile.
+
+  /* Read/write attachment to a mirrored/ing tile - must be
+   *  thoughtful.
    */
-  tile_cache_insert (tile);
+  if (dirty)
+    {
+      /* Doing a read/write reference to a mirroring/ed tile -
+       *  we'll have to turn the tile into a 'real' tile.
+       *  Then return - we're done.
+       */
+      {
+	if (tile_is_mirroring (tile) | tile_is_mirrored (tile))
+	  {
+#if defined (TILE_DEBUG)
+	    g_print ("r/w to mir'd/ing - isolating: ");
+#endif
 
-  /* Call 'tile_manager_validate' if the tile was invalid.
+	    tile_isolate (tile);
+	  }
+      }
+    }
+
+  /* Mark the tile as dirty if it's being ref'd as dirtyable.
    */
+  tile->dirty |= dirty;
 
 #if USE_PTHREADS
   pthread_mutex_unlock(&(tile->mutex));
 #endif
+
+  /* Call 'tile_manager_validate' if the tile was invalid.
+   */
   if (!tile->valid)
     tile_manager_validate ((TileManager*) tile->tm, tile);
-  
 
 }
 
+
 void
 #if defined (TILE_DEBUG) && defined (__GNUC__)
 _tile_unref (Tile *tile, int dirty, char *func_name)
@@ -89,20 +486,76 @@ tile_unref (Tile *tile, int dirty)
 #ifdef USE_PTHREADS
   pthread_mutex_lock(&(tile->mutex));
 #endif
-  /*  g_print ("tile_unref:  0x%08x  %s\n", tile, func_name); */
 
+#if defined (TILE_DEBUG) && defined (__GNUC__) && defined (MUCH_TILE_DEBUG)
+  g_print ("tile_unref:  %02d  %c  %p  %s\n", tile->ref_count,
+	   dirty?'d':' ',
+	   tile, func_name);
+#endif
+
+  /*    g_print ("tile_unref:  %02d  %c  %p\n", tile->ref_count,
+	   dirty?'d':' ',
+	   tile);*/
+
+  /* Decrement the global reference count.
+   */
   tile_ref_count -= 1;
 
-  /* Decrement the reference count.
+  /* Decrement this tile's reference count.
    */
   tile->ref_count -= 1;
 
   /* Mark the tile dirty if indicated