/* Face data structures.
   Copyright (C) 1995 Board of Trustees, University of Illinois.
   Copyright (C) 1995, 2002, 2005, 2010 Ben Wing
   Copyright (C) 2010 Didier Verna

This file is part of XEmacs.

XEmacs is free software: you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by the
Free Software Foundation, either version 3 of the License, or (at your
option) any later version.

XEmacs 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 General Public License
for more details.

You should have received a copy of the GNU General Public License
along with XEmacs.  If not, see <http://www.gnu.org/licenses/>. */

/* Synched up with: Not in FSF. */

#ifndef INCLUDED_faces_h_
#define INCLUDED_faces_h_

/* a Lisp_Face is the C object corresponding to a face.  There is one
   of these per face.  It basically contains all of the specifiers for
   the built-in face properties, plus the plist of user-specified
   properties. */

struct Lisp_Face
{
  NORMAL_LISP_OBJECT_HEADER header;

  Lisp_Object name;
  Lisp_Object doc_string;
  unsigned int dirty :1; /* Set whenever a face property is changed on
			    a face. */

  Lisp_Object foreground;
  Lisp_Object foreback;
  Lisp_Object background;
  Lisp_Object font;

  Lisp_Object display_table;
  Lisp_Object background_pixmap;
  Lisp_Object background_placement;

  Lisp_Object underline;
  Lisp_Object strikethru;
  Lisp_Object highlight;
  Lisp_Object dim;
  Lisp_Object blinking;
  Lisp_Object reverse;
  Lisp_Object shrink;

  Lisp_Object plist;

  Lisp_Object charsets_warned_about;
};

/*

   A face cache element caches the results of instantiating the
   properties of a face in a particular window. (Instantiation can
   take a long time so this is very important.) Each window contains
   an array of face cache elements (called the "face cache"), one for
   each face that has been seen in the window so far.

   Some tricky stuff is done to make sure the face cache does not
   become inconsistent:

   1) Switching buffers in a window clears the face cache for that
      window, because this can change the way any property is
      instantiated in the window.
   2) Setting a face property causes that face to be marked as
      dirty.  This causes various stuff to happen to make sure
      the appropriate face cache elements are invalidated.
      (#### Actually this doesn't work quite right, and errs
      too much on the side of invalidating unnecessary stuff.)

   There are also face cache elements for "merged faces", which are the
   result of merging all the faces that overlap a particular buffer
   position.  The merging is always done in the context of a particular
   domain (specifically, a window), and the face cache element is
   specific to a particular window. (Face cache elements are contained
   in an array that is attached to each struct_window.) The reason that
   the merging takes place in the context of a particular window has
   to do with the way the merging works:

   1) All extents overlying the buffer position are sorted by descending
      priority.
   2) The property of a particular merged face comes from the highest-
      priority face that specifies a value for that particular property.
   3) The way to determine whether a face specifies a value for a
      particular property is to instantiate that face's property in
      the window in question with the no-fallback option set, to
      see if we got anything.

   For Mule, things get a bit trickier because there can be multiple
   fonts per face/window combination -- the charset is an argument
   to specifier-instance.

   We have two possible data structure representations:

   1) Keep the original "one font per face cache element" representation
      and use a different face cache element for each charset.
   2) Allow multiple fonts to be in a single face cache element.

   I've chosen to use (2) -- the data structure gets more complicated
   but the algorithms for maintaining face cache elements end up
   simpler.
 */

#define NUM_STATIC_CACHEL_FACES 4

typedef struct
{
  Stynarr_declare (int, NUM_STATIC_CACHEL_FACES);
} int_stynarr;

typedef struct
{
  Stynarr_declare (unsigned_char, NUM_STATIC_CACHEL_FACES);
} unsigned_char_stynarr;

typedef struct
{
  Stynarr_declare (Lisp_Object_pair, NUM_STATIC_CACHEL_FACES);
} Lisp_Object_pair_stynarr;

typedef struct face_cachel face_cachel;
struct face_cachel
{
  /* There are two kinds of cachels; those created from a single face
     and those created by merging more than one face.  In the former
     case, the FACE element specifies the face used.  In the latter
     case, the MERGED_FACES_STATIC and MERGED_FACES elements specify
     the faces used for merging by giving the indices of the
     corresponding single-face cachels.

     Formerly we didn't bother to keep track of the faces used for
     merging.  We do now because we need to do so because there is no
     other way to properly handle multiple charsets for Mule in the
     presence of display tables short of always computing the values
     for all charsets, which is very expensive.  Instead, we use a
     lazy scheme where we only compute the font for a particular charset
     when it is needed. (The exception is the font for the ASCII charset.
     We always compute it, just like the other attributes, because
     many places in the C code refer to the font of the ASCII charset
     and expect it to always be there.)

     We store the first four faces in a static array, and use a
     Dynarr for the rest.  This has the advantage that the space used
     is small but the Dynarr will almost never be created, so we
     won't spend much time in malloc()/free().

     The order of the faces here is decreasing extent priority. */
  Lisp_Object face;

  int_stynarr merged_faces;

  /* The values stored here are computed by calling specifier_instance()
     on the appropriate specifiers.  This means that we will have either
     a value computed from the face itself or a value computed from the
     default face.  We need to distinguish the two so that merging works
     properly -- a value that comes from the default face is treated
     as "unspecified" during merging and is overridden by lower-priority
     faces.  This is what the _specified flags below are for. */

  Lisp_Object foreground;
  Lisp_Object foreback;
  Lisp_Object background;

  /* Static dynarr, mapping charsets to font objects.  Note: The use of an
     unordered list like this make lookup O(n), potentially slower than a
     hash table; but the associated constant will be very small, and it's
     rare that there will be very many charsets associated with this cachel
     (at most 128 in the previous scheme, and many fewer in practice, often
     only one). */
  Lisp_Object_pair_stynarr font;

  Lisp_Object display_table;
  Lisp_Object background_pixmap;
  Lisp_Object background_placement;

  unsigned int underline :1;
  unsigned int strikethru :1;
  unsigned int highlight :1;
  unsigned int dim :1;
  unsigned int blinking :1;
  unsigned int reverse :1;
  unsigned int shrink :1;

  /* Used when merging to tell if the above field represents an actual
     value of this face or a fallback value. */
  unsigned_char_stynarr font_specified;
  unsigned int foreground_specified :1;
  unsigned int foreback_specified :1;
  unsigned int background_specified :1;
  unsigned int display_table_specified :1;
  unsigned int background_pixmap_specified :1;
  unsigned int background_placement_specified :1;

  unsigned int strikethru_specified :1;
  unsigned int underline_specified :1;
  unsigned int highlight_specified :1;
  unsigned int dim_specified :1;
  unsigned int blinking_specified :1;
  unsigned int reverse_specified :1;
  unsigned int shrink_specified :1;

  /* The updated flag is set after we calculate the values for the
     face cachel and cleared whenever a face changes, to indicate
     that the values stored here might be wrong.  The next time
     we go to access the values, we recompute them; if any values
     change, we set the DIRTY flag, which tells the output routines
     that a face value has in fact changed and the sections of text
     using this face need to be redrawn.

     It is trickier with fonts because we don't automatically
     recompute the fonts but do it only when it is necessary.
     (The ASCII font is an exception, of course; see above).

     In the case of fonts, we maintain a separate updated flag
     for each font.  Whenever we need to access the font for
     a particular charset, we recalculate it if either its
     value is Qunbound (meaning it's never been computed at all)
     or the updated flag is not set.  We set the dirty flag if
     the value is not the same as before and the previous value
     was not Qunbound.

     #### Note that we don't yet deal with the case of the new
     value being Qunbound, as could happen if no fonts of the
     right sort are available on the system.  In this case, the
     whole program will just crash.  For the moment, this is
     OK (for debugging purposes) but we should fix this by
     storing a "blank font" if the instantiation fails. */
  unsigned int dirty :1;
  unsigned int updated :1;
  unsigned_char_stynarr font_updated;

  /* Whether the font for the charset in question was determined in the
     "final stage"; that is, the last stage Lisp code could specify it,
     after the initial stage and before the fallback. */ 
  unsigned_char_stynarr font_final_stage;
};


DECLARE_LISP_OBJECT (face, Lisp_Face);
#define XFACE(x) XRECORD (x, face, Lisp_Face)
#define wrap_face(p) wrap_record (p, face)
#define FACEP(x) RECORDP (x, face)
#define CHECK_FACE(x) CHECK_RECORD (x, face)

Lisp_Object ensure_face_cachel_contains_charset (struct face_cachel *cachel,
						 Lisp_Object domain,
						 Lisp_Object charset);
void ensure_face_cachel_complete (struct face_cachel *cachel,
				  Lisp_Object domain, const Ibyte *ptr,
				  Bytecount len);
void update_face_cachel_data (struct face_cachel *cachel,
			      Lisp_Object domain,
			      Lisp_Object face);
void face_cachel_char_font_metric_info (struct face_cachel *cachel,
					Lisp_Object domain,
					const Ibyte *ptr, Bytecount len,
					struct font_metric_info *fm);
void mark_face_cachels_as_clean (struct window *w);
void mark_face_cachels_as_not_updated (struct window *w);
void reset_face_cachel (struct face_cachel *inst);
void reset_face_cachels (struct window *w);
face_index get_builtin_face_cache_index (struct window *w,
					 Lisp_Object face);
/* WARNING: this interface may change. */
face_index merge_face_list_to_cache_index (struct window *w,
					   Lisp_Object *face_list, int count);

#ifdef MEMORY_USAGE_STATS
int compute_face_cachel_usage (face_cachel_dynarr *face_cachels,
			       struct usage_stats *ustats);
#endif /* MEMORY_USAGE_STATS */

EXFUN (Fface_name, 1);
EXFUN (Ffind_face, 1);
EXFUN (Fget_face, 1);

extern Lisp_Object Qstrikethru, Vbuilt_in_face_specifiers, Vdefault_face;
extern Lisp_Object Vleft_margin_face, Vpointer_face, Vright_margin_face;
extern Lisp_Object Vtext_cursor_face, Vvertical_divider_face;
extern Lisp_Object Vtoolbar_face, Vgui_element_face, Vwidget_face;

void mark_all_faces_as_clean (void);
void init_frame_faces (struct frame *f);
void init_device_faces (struct device *d);
void init_global_faces (struct device *d);
face_index get_extent_fragment_face_cache_index (struct window *w,
						 struct extent_fragment *ef);
void update_frame_face_values (struct frame *f);
void face_property_was_changed (Lisp_Object face, Lisp_Object property,
				Lisp_Object locale);
void default_face_font_info (Lisp_Object domain, int *ascent,
			     int *descent, int *width, int *height,
			     int *proportional_p);
void default_face_width_and_height (Lisp_Object domain, int *width,
				    int *height);

/* Return the font corresponding to CHARSET in CACHEL, or Qunbound if not
   found.  Could just use FACE_CACHEL_OFFSET() below. */

DECLARE_INLINE_HEADER (
Lisp_Object
FACE_CACHEL_FONT (struct face_cachel *cachel, Lisp_Object charset)
)
{
  int i;
  for (i = 0; i < Stynarr_length (cachel->font); i++)
    {
      Lisp_Object_pair *el = Stynarr_atp (cachel->font, i);
      if (EQ (el->key, charset))
	return el->value;
    }
  return Qunbound;
}

/* Return the offset corresponding to CHARSET in CACHEL, or -1 if not
   found. */

DECLARE_INLINE_HEADER (
int
FACE_CACHEL_OFFSET (struct face_cachel *cachel, Lisp_Object charset)
)
{
  int i;
  for (i = 0; i < Stynarr_length (cachel->font); i++)
    {
      Lisp_Object_pair *el = Stynarr_atp (cachel->font, i);
      if (EQ (el->key, charset))
	return i;
    }
  return -1;
}

/* Return the offset corresponding to CHARSET in CACHEL; if necessary, add
   the charset to cachel, with font value of Qunbound. */

DECLARE_INLINE_HEADER (
int
FACE_CACHEL_OFFSET_ENSURE (struct face_cachel *cachel, Lisp_Object charset)
)
{
  int i = FACE_CACHEL_OFFSET (cachel, charset);
  if (i == -1)
    {
      Lisp_Object_pair lop;
      lop.key = charset;
      lop.value = Qunbound;
      i = Stynarr_length (cachel->font);
      Stynarr_add (cachel->font, lop);
      Stynarr_add (cachel->font_specified, 0);
      Stynarr_add (cachel->font_updated, 0);
      Stynarr_add (cachel->font_final_stage, 0);
    }
  return i;
}

#define WINDOW_FACE_CACHEL(window, index) \
  Dynarr_atp ((window)->face_cachels, index)

/* UNSAFE because it evaluates OFFSET and (CACHEL) multiply */
#define FACE_CACHEL_FINDEX_UNSAFE(cachel, offset)                       \
  Stynarr_at (cachel->merged_faces, offset)
#define FACE_CACHEL_NFACES(cachel)                                      \
  Stynarr_length (cachel->merged_faces)

#define WINDOW_FACE_CACHEL_FACE(window, index)                          \
  (WINDOW_FACE_CACHEL (window, index)->face)
#define WINDOW_FACE_CACHEL_FOREGROUND(window, index)                    \
  (WINDOW_FACE_CACHEL (window, index)->foreground)
#define WINDOW_FACE_CACHEL_FOREBACK(window, index)			\
  (WINDOW_FACE_CACHEL (window, index)->foreback)
#define WINDOW_FACE_CACHEL_BACKGROUND(window, index)			\
  (WINDOW_FACE_CACHEL (window, index)->background)
/* #### This can be referenced by various functions,
   but face_cachels isn't initialized for the stream device.
   Since it doesn't need the value we just return nil here to avoid
   blowing up in multiple places. */
#define WINDOW_FACE_CACHEL_FONT(window, index, charset)                 \
  ((window)->face_cachels                                               \
   ? FACE_CACHEL_FONT (WINDOW_FACE_CACHEL (window, index), charset)     \
   : Qnil)
#define WINDOW_FACE_CACHEL_DISPLAY_TABLE(window, index)                 \
  (WINDOW_FACE_CACHEL (window, index)->display_table)
#define WINDOW_FACE_CACHEL_BACKGROUND_PIXMAP(window, index)             \
  (WINDOW_FACE_CACHEL (window, index)->background_pixmap)
#define WINDOW_FACE_CACHEL_BACKGROUND_PLACEMENT(window, index)		\
  (WINDOW_FACE_CACHEL (window, index)->background_placement)
#define WINDOW_FACE_CACHEL_DIRTY(window, index)				\
  (WINDOW_FACE_CACHEL (window, index)->dirty)
#define WINDOW_FACE_CACHEL_UNDERLINE_P(window, index)                   \
  (WINDOW_FACE_CACHEL (window, index)->underline)
#define WINDOW_FACE_CACHEL_HIGHLIGHT_P(window, index)                   \
  (WINDOW_FACE_CACHEL (window, index)->highlight)
#define WINDOW_FACE_CACHEL_DIM_P(window, index)                         \
  (WINDOW_FACE_CACHEL (window, index)->dim)
#define WINDOW_FACE_CACHEL_BLINKING_P(window, index)                    \
  (WINDOW_FACE_CACHEL (window, index)->blinking)
#define WINDOW_FACE_CACHEL_REVERSE_P(window, index)                     \
  (WINDOW_FACE_CACHEL (window, index)->reverse)
#define WINDOW_FACE_CACHEL_SHRINK_P(window, index)			\
  (WINDOW_FACE_CACHEL (window, index)->shrink)

#define FACE_PROPERTY_SPECIFIER(face, property) Fget (face, property, Qnil)

#define FACE_PROPERTY_INSTANCE_1(face, property, domain, errb, no_fallback, depth)	\
  specifier_instance (FACE_PROPERTY_SPECIFIER (face, property), Qunbound, \
		      domain, errb, 1, no_fallback, depth)

#define FACE_PROPERTY_INSTANCE(face, property, domain, no_fallback, depth)	\
  FACE_PROPERTY_INSTANCE_1 (face, property, domain, ERROR_ME_DEBUG_WARN, \
			    no_fallback, depth)

Lisp_Object face_property_matching_instance
			(Lisp_Object face,
			 Lisp_Object property,
			 Lisp_Object charset,
			 Lisp_Object domain,
			 Error_Behavior errb,
			 int no_fallback,
			 Lisp_Object depth,
			 enum font_specifier_matchspec_stages stages);

#define FACE_PROPERTY_SPEC_LIST(face, property, locale)			\
  Fspecifier_spec_list (FACE_PROPERTY_SPECIFIER (face, property),	\
			locale, Qnil, Qnil)
#define SET_FACE_PROPERTY(face, property, value, locale, tag, how_to_add) \
  Fadd_spec_to_specifier (FACE_PROPERTY_SPECIFIER (face, property),	\
			  value, locale, tag, how_to_add)

#define FACE_FOREGROUND(face, domain)					\
  FACE_PROPERTY_INSTANCE (face, Qforeground, domain, 0, Qzero)
#define FACE_FOREBACK(face, domain)					\
  FACE_PROPERTY_INSTANCE (face, Qforeback, domain, 0, Qzero)
#define FACE_BACKGROUND(face, domain)					\
  FACE_PROPERTY_INSTANCE (face, Qbackground, domain, 0, Qzero)

/* Calling this function on the default face with the ASCII character set
   may delete any X11 frames; see the code at the end of
   x_find_charset_font. */
#define FACE_FONT(face, domain, charset)				\
  face_property_matching_instance (face, Qfont, charset, domain,	\
				   ERROR_ME_DEBUG_WARN, 0, Qzero,	\
				   STAGE_INITIAL)
#define FACE_DISPLAY_TABLE(face, domain)				\
  FACE_PROPERTY_INSTANCE (face, Qdisplay_table, domain, 0, Qzero)
#define FACE_BACKGROUND_PIXMAP(face, domain)				\
  FACE_PROPERTY_INSTANCE (face, Qbackground_pixmap, domain, 0, Qzero)

extern Lisp_Object Qbackground_placement;
#define FACE_BACKGROUND_PLACEMENT(face, domain)				\
  FACE_PROPERTY_INSTANCE (face, Qbackground_placement, domain, 0, Qzero)

#define FACE_UNDERLINE_P(face, domain)					\
  (!NILP (FACE_PROPERTY_INSTANCE (face, Qunderline, domain, 0, Qzero)))
#define FACE_STRIKETHRU_P(face, domain)					\
  (!NILP (FACE_PROPERTY_INSTANCE (face, Qstrikethru, domain, 0, Qzero)))
#define FACE_HIGHLIGHT_P(face, domain)					\
  (!NILP (FACE_PROPERTY_INSTANCE (face, Qhighlight, domain, 0, Qzero)))
#define FACE_DIM_P(face, domain)					\
  (!NILP (FACE_PROPERTY_INSTANCE (face, Qdim, domain, 0, Qzero)))
#define FACE_BLINKING_P(face, domain)					\
  (!NILP (FACE_PROPERTY_INSTANCE (face, Qblinking, domain, 0, Qzero)))
#define FACE_REVERSE_P(face, domain)					\
  (!NILP (FACE_PROPERTY_INSTANCE (face, Qreverse, domain, 0, Qzero)))
#define FACE_SHRINK_P(face, domain)					\
  (!NILP (FACE_PROPERTY_INSTANCE (face, Qshrink, domain, 0, Qzero)))

#endif /* INCLUDED_faces_h_ */
