/* Routines to compute the current syntactic context, for font-lock mode. Copyright (C) 1992, 1993, 1994 Free Software Foundation, Inc. Copyright (C) 1995 Sun Microsystems, Inc. Copyright (C) 2002, 2003, 2010 Ben Wing. 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 . */ /* Synched up with: Not in FSF. */ /* This code computes the syntactic context of the current point, that is, whether point is within a comment, a string, what have you. It does this by picking a point "known" to be outside of any syntactic constructs and moving forward, examining the syntax of each character. Two caches are used: one caches the last point computed, and the other caches the last point at the beginning of a line. This makes there be little penalty for moving left-to-right on a line a character at a time; makes starting over on a line be cheap; and makes random-accessing within a line relatively cheap. When we move to a different line farther down in the file (but within the current top-level form) we simply continue computing forward. If we move backward more than a line, or move beyond the end of the current tlf, or switch buffers, then we call `beginning-of-defun' and start over from there. #### We should really rewrite this to keep extents over the buffer that hold the current syntactic information. This would be a big win. This way there would be no guessing or incorrect results. */ #include #ifdef USE_C_FONT_LOCK #include "lisp.h" #include "buffer.h" #include "insdel.h" #include "syntax.h" Lisp_Object Qcomment; Lisp_Object Qblock_comment; Lisp_Object Qbeginning_of_defun; enum syntactic_context { context_none, context_string, context_comment, context_block_comment, context_generic_comment, context_generic_string }; enum block_comment_context { ccontext_none, ccontext_start1, ccontext_start2, ccontext_end1 }; enum comment_style { comment_style_none, comment_style_a, comment_style_b }; struct context_cache { Charbpos start_point; /* beginning of defun */ Charbpos cur_point; /* cache location */ Charbpos end_point; /* end of defun */ struct buffer *buffer; /* does this need to be staticpro'd? */ enum syntactic_context context; /* single-char-syntax state */ enum block_comment_context ccontext; /* block-comment state */ enum comment_style style; /* which comment group */ Ichar scontext; /* active string delimiter */ int depth; /* depth in parens */ int backslash_p; /* just read a backslash */ int needs_its_head_reexamined; /* we're apparently outside of a top level form, and far away from it. This is a bad situation because it will lead to constant slowness as we keep going way back to that form and moving forward again. In this case, we try to compute a "pseudo- top-level-form" where the depth is 0 and the context is none at both ends. */ }; /* We have two caches; one for the current point and one for the beginning of line. We used to rely on the caller to tell us when to invalidate them, but now we do it ourselves; it lets us be smarter. */ static struct context_cache context_cache; static struct context_cache bol_context_cache; int font_lock_debug; #define reset_context_cache(cc) memset (cc, 0, sizeof (struct context_cache)) /* This function is called from signal_after_change() to tell us when textual changes are made so we can flush our caches when necessary. We make the following somewhat heuristic assumptions: (remember that current_point is always >= start_point, but may be less than or greater than end_point (we might not be inside any top-level form)). 1) Textual changes before the beginning of the current top-level form don't affect anything; all we need to do is offset the caches appropriately. 2) Textual changes right at the beginning of the current top-level form messes things up and requires that we flush the caches. 3) Textual changes after the beginning of the current top-level form and before one or both or the caches invalidates the corresponding cache(s). 4) Textual changes after the caches and before the end of the current top-level form don't affect anything; all we need to do is offset the caches appropriately. 5) Textual changes right at the end of the current top-level form necessitate recomputing that end value. 6) Textual changes after the end of the current top-level form are ignored. */ void font_lock_maybe_update_syntactic_caches (struct buffer *buf, Charbpos start, Charbpos orig_end, Charbpos new_end) { /* Note: either both context_cache and bol_context_cache are valid and point to the same buffer, or both are invalid. If we have to invalidate just context_cache, we recopy it from bol_context_cache. */ if (context_cache.buffer != buf) /* caches don't apply */ return; /* NOTE: The order of the if statements below is important. If you change them around unthinkingly, you will probably break something. */ if (orig_end <= context_cache.start_point - 1) { /* case 1: before the beginning of the current top-level form */ Charcount diff = new_end - orig_end; if (font_lock_debug) stderr_out ("font-lock; Case 1\n"); context_cache.start_point += diff; context_cache.cur_point += diff; context_cache.end_point += diff; bol_context_cache.start_point += diff; bol_context_cache.cur_point += diff; bol_context_cache.end_point += diff; } else if (start <= context_cache.start_point) { if (font_lock_debug) stderr_out ("font-lock; Case 2\n"); /* case 2: right at the current top-level form (paren that starts top level form got deleted or moved away from the newline it was touching) */ reset_context_cache (&context_cache); reset_context_cache (&bol_context_cache); } /* OK, now we know that the start is after the beginning of the current top-level form. */ else if (start < bol_context_cache.cur_point) { if (font_lock_debug) stderr_out ("font-lock; Case 3 (1)\n"); /* case 3: after the beginning of the current top-level form and before both of the caches */ reset_context_cache (&context_cache); reset_context_cache (&bol_context_cache); } else if (start < context_cache.cur_point) { if (font_lock_debug) stderr_out ("font-lock; Case 3 (2)\n"); /* case 3: but only need to invalidate one cache */ context_cache = bol_context_cache; } /* OK, now we know that the start is after the caches. */ else if (start >= context_cache.end_point) { if (font_lock_debug) stderr_out ("font-lock; Case 6\n"); /* case 6: after the end of the current top-level form and after the caches. */ } else if (orig_end <= context_cache.end_point - 2) { /* case 4: after the caches and before the end of the current top-level form */ Charcount diff = new_end - orig_end; if (font_lock_debug) stderr_out ("font-lock; Case 4\n"); context_cache.end_point += diff; bol_context_cache.end_point += diff; } else { if (font_lock_debug) stderr_out ("font-lock; Case 5\n"); /* case 5: right at the end of the current top-level form */ context_cache.end_point = context_cache.start_point - 1; bol_context_cache.end_point = context_cache.start_point - 1; } } /* This function is called from Fkill_buffer(). */ void font_lock_buffer_was_killed (struct buffer *buf) { if (context_cache.buffer == buf) { reset_context_cache (&context_cache); reset_context_cache (&bol_context_cache); } } static Charbpos beginning_of_defun (struct buffer *buf, Charbpos pt) { /* This function can GC */ Charbpos opt = BUF_PT (buf); if (pt == BUF_BEGV (buf)) return pt; BUF_SET_PT (buf, pt); /* There used to be some kludginess to call c++-beginning-of-defun if we're in C++ mode. There's no point in this any more; we're using cc-mode. If you really want to get the old c++ mode working, fix it rather than the C code. */ call0_in_buffer (buf, Qbeginning_of_defun); pt = BUF_PT (buf); BUF_SET_PT (buf, opt); return pt; } static Charbpos end_of_defun (struct buffer *buf, Charbpos pt) { Lisp_Object retval = scan_lists (buf, pt, 1, 0, 0, 1); if (NILP (retval)) return BUF_ZV (buf); else return XFIXNUM (retval); } /* Set up context_cache for attempting to determine the syntactic context in buffer BUF at point PT. */ static void setup_context_cache (struct buffer *buf, Charbpos pt) { int recomputed_start_point = 0; /* This function can GC */ if (context_cache.buffer != buf || pt < context_cache.start_point) { start_over: if (font_lock_debug) stderr_out ("reset context cache\n"); /* OK, completely invalid. */ reset_context_cache (&context_cache); reset_context_cache (&bol_context_cache); } if (!context_cache.buffer) { /* Need to recompute the start point. */ if (font_lock_debug) stderr_out ("recompute start\n"); context_cache.start_point = beginning_of_defun (buf, pt); recomputed_start_point = 1; bol_context_cache.start_point = context_cache.start_point; bol_context_cache.buffer = context_cache.buffer = buf; } if (context_cache.end_point < context_cache.start_point) { /* Need to recompute the end point. */ if (font_lock_debug) stderr_out ("recompute end\n"); context_cache.end_point = end_of_defun (buf, context_cache.start_point); bol_context_cache.end_point = context_cache.end_point; } if (bol_context_cache.cur_point == 0 || pt < bol_context_cache.cur_point) { if (font_lock_debug) stderr_out ("reset to start\n"); if (pt > context_cache.end_point /* 3000 is some arbitrary delta but seems reasonable; about the size of a reasonable function */ && pt - context_cache.end_point > 3000) /* If we're far past the end of the top level form, don't trust it; recompute it. */ { /* But don't get in an infinite loop doing this. If we're really far past the end of the top level form, try to compute a pseudo-top-level form. */ if (recomputed_start_point) context_cache.needs_its_head_reexamined = 1; else /* force recomputation */ goto start_over; } /* Go to the nearest end of the top-level form that's before us. */ if (pt > context_cache.end_point) pt = context_cache.end_point; else pt = context_cache.start_point; /* Reset current point to start of buffer. */ context_cache.cur_point = pt; context_cache.context = context_none; context_cache.ccontext = ccontext_none; context_cache.style = comment_style_none; context_cache.scontext = '\000'; context_cache.depth = 0; /* #### shouldn't this be checking the character's syntax instead of explicitly testing for backslash characters? */ context_cache.backslash_p = ((pt > 1) && (BUF_FETCH_CHAR (buf, pt - 1) == '\\')); /* Note that the BOL context cache may not be at the beginning of the line, but that should be OK, nobody's checking. */ bol_context_cache = context_cache; return; } else if (pt < context_cache.cur_point) { if (font_lock_debug) stderr_out ("reset to bol\n"); /* bol cache is OK but current_cache is not. */ context_cache = bol_context_cache; return; } else if (pt <= context_cache.end_point) { if (font_lock_debug) stderr_out ("everything is OK\n"); /* in same top-level form. */ return; } { /* OK, we're past the end of the top-level form. */ Charbpos maxpt = max (context_cache.end_point, context_cache.cur_point); #if 0 int shortage; #endif if (font_lock_debug) stderr_out ("past end\n"); if (pt <= maxpt) /* OK, fine. */ return; #if 0 /* This appears to cause huge slowdowns in files which have no top-level forms. In any case, it's not really necessary that we know for sure the top-level form we're in; if we're in a form but the form we have recorded is the previous one, it will be OK. */ scan_buffer (buf, '\n', maxpt, pt, 1, &shortage, 1); if (!shortage) /* If there was a newline in the region past the known universe, we might be inside another top-level form, so start over. Otherwise, we're outside of any top-level forms and we know the one directly before us, so it's OK. */ goto start_over; #endif } } /* You'd think it wouldn't be necessary to cast something to the type it's already defined is, but if you're GCC, you apparently think differently */ #define SYNTAX_START_STYLE(c1, c2) \ ((enum comment_style) \ (SYNTAX_CODES_MATCH_START_P (c1, c2, SYNTAX_COMMENT_STYLE_A) ? \ comment_style_a : \ SYNTAX_CODES_MATCH_START_P (c1, c2, SYNTAX_COMMENT_STYLE_B) ? \ comment_style_b : \ comment_style_none)) #define SYNTAX_END_STYLE(c1, c2) \ ((enum comment_style) \ (SYNTAX_CODES_MATCH_END_P (c1, c2, SYNTAX_COMMENT_STYLE_A) ? \ comment_style_a : \ SYNTAX_CODES_MATCH_END_P (c1, c2, SYNTAX_COMMENT_STYLE_B) ? \ comment_style_b : \ comment_style_none)) #define SINGLE_SYNTAX_STYLE(c) \ ((enum comment_style) \ (SYNTAX_CODE_MATCHES_1CHAR_P (c, SYNTAX_COMMENT_STYLE_A) ? \ comment_style_a : \ SYNTAX_CODE_MATCHES_1CHAR_P (c, SYNTAX_COMMENT_STYLE_B) ? \ comment_style_b : \ comment_style_none)) /* Set up context_cache for position PT in BUF. */ static void find_context (struct buffer *buf, Charbpos pt) { /* This function can GC */ Ichar prev_c, c; int prev_syncode, syncode; Charbpos target = pt; struct syntax_cache *scache; int spec = specpdl_depth (); /* If we are narrowed, we will get confused. In fact, we are quite often narrowed when this function is called. */ if (BUF_BEGV (buf) != BUF_BEG (buf) || BUF_ZV (buf) != BUF_Z (buf)) { record_unwind_protect (save_restriction_restore, save_restriction_save (buf)); Fwiden (wrap_buffer (buf)); } setup_context_cache (buf, pt); pt = context_cache.cur_point; scache = setup_buffer_syntax_cache (buf, pt > BUF_BEGV (buf) ? pt - 1 : pt, 1); if (pt > BUF_BEGV (buf)) { c = BUF_FETCH_CHAR (buf, pt - 1); syncode = SYNTAX_CODE_FROM_CACHE (scache, c); } else { c = '\n'; /* to get bol_context_cache at point-min */ syncode = Swhitespace; } for (; pt < target; pt++, context_cache.cur_point = pt) { if (context_cache.needs_its_head_reexamined) { if (context_cache.depth == 0 && context_cache.context == context_none) { /* We've found an anchor spot. Try to put the start of defun within 6000 chars of the target, and the end of defun as close as possible. 6000 is also arbitrary but tries to strike a balance between two conflicting pulls when dealing with a file that has lots of stuff sitting outside of a top- level form: a) If you move past the start of defun, you will have to recompute defun, which in this case means that start of defun goes all the way back to the beginning of the file; so you want to set start of defun a ways back from the current point. b) If you move a line backwards but within start of defun, you have to move back to start of defun; so you don't want start of defun too far from the current point. */ if (target - context_cache.start_point > 6000) context_cache.start_point = pt; context_cache.end_point = pt; bol_context_cache = context_cache; } } UPDATE_SYNTAX_CACHE_FORWARD (scache, pt); prev_c = c; prev_syncode = syncode; c = BUF_FETCH_CHAR (buf, pt); syncode = SYNTAX_CODE_FROM_CACHE (scache, c); if (prev_c == '\n') bol_context_cache = context_cache; if (context_cache.backslash_p) { context_cache.backslash_p = 0; continue; } switch (SYNTAX_FROM_CODE (syncode)) { case Sescape: context_cache.backslash_p = 1; break; case Sopen: if (context_cache.context == context_none) context_cache.depth++; break; case Sclose: if (context_cache.context == context_none) context_cache.depth--; break; case Scomment: if (context_cache.context == context_none) { context_cache.context = context_comment; context_cache.ccontext = ccontext_none; context_cache.style = SINGLE_SYNTAX_STYLE (syncode); assert (context_cache.style != comment_style_none); } break; case Sendcomment: if (context_cache.style != SINGLE_SYNTAX_STYLE (syncode)) ; else if (context_cache.context == context_comment) { context_cache.context = context_none; context_cache.style = comment_style_none; } else if (context_cache.context == context_block_comment && (context_cache.ccontext == ccontext_start2 || context_cache.ccontext == ccontext_end1)) { context_cache.context = context_none; context_cache.ccontext = ccontext_none; context_cache.style = comment_style_none; } break; case Sstring: { if (context_cache.context == context_string && context_cache.scontext == c) { context_cache.context = context_none; context_cache.scontext = '\000'; } else if (context_cache.context == context_none) { Lisp_Object stringtermobj = syntax_match (scache->syntax_table, c); Ichar stringterm; if (CHARP (stringtermobj)) stringterm = XCHAR (stringtermobj); else stringterm = c; context_cache.context = context_string; context_cache.scontext = stringterm; context_cache.ccontext = ccontext_none; } break; } case Scomment_fence: { if (context_cache.context == context_generic_comment) { context_cache.context = context_none; } else if (context_cache.context == context_none) { context_cache.context = context_generic_comment; context_cache.ccontext = ccontext_none; } break; } case Sstring_fence: { if (context_cache.context == context_generic_string) { context_cache.context = context_none; } else if (context_cache.context == context_none) { context_cache.context = context_generic_string; context_cache.ccontext = ccontext_none; } break; } default: ; } /* That takes care of the characters with manifest syntax. Now we've got to hack multi-char sequences that start and end block comments. */ if ((SYNTAX_CODE_COMMENT_BITS (syncode) & SYNTAX_SECOND_CHAR_START) && context_cache.context == context_none && context_cache.ccontext == ccontext_start1 && SYNTAX_CODES_START_P (prev_syncode, syncode) /* the two chars match */ ) { context_cache.ccontext = ccontext_start2; context_cache.style = SYNTAX_START_STYLE (prev_syncode, syncode); assert (context_cache.style != comment_style_none); } else if ((SYNTAX_CODE_COMMENT_BITS (syncode) & SYNTAX_FIRST_CHAR_START) && context_cache.context == context_none && (context_cache.ccontext == ccontext_none || context_cache.ccontext == ccontext_start1)) { context_cache.ccontext = ccontext_start1; context_cache.style = comment_style_none; /* should be this already*/ } else if ((SYNTAX_CODE_COMMENT_BITS (syncode) & SYNTAX_SECOND_CHAR_END) && context_cache.context == (enum syntactic_context) context_block_comment && context_cache.ccontext == (enum block_comment_context) ccontext_end1 && SYNTAX_CODES_END_P (prev_syncode, syncode) && /* the two chars match */ context_cache.style == SYNTAX_END_STYLE (prev_syncode, syncode) ) { context_cache.context = context_none; context_cache.ccontext = ccontext_none; context_cache.style = comment_style_none; } else if ((SYNTAX_CODE_COMMENT_BITS (syncode) & SYNTAX_FIRST_CHAR_END) && context_cache.context == context_block_comment && context_cache.style == SINGLE_SYNTAX_STYLE (syncode) && (context_cache.ccontext == ccontext_start2 || context_cache.ccontext == ccontext_end1)) /* #### is it right to check for end1 here?? yes, because this might be a repetition of the first char of a comment-end sequence. ie, '/xxx foo xxx/' or '/xxx foo x/', where 'x' = '*' -- mct */ { assert (context_cache.style != comment_style_none); context_cache.ccontext = ccontext_end1; } else if (context_cache.ccontext == ccontext_start1) { assert (context_cache.context == context_none); context_cache.ccontext = ccontext_none; } else if (context_cache.ccontext == ccontext_end1) { assert (context_cache.context == context_block_comment); context_cache.context = context_none; context_cache.ccontext = ccontext_start2; } if (context_cache.ccontext == ccontext_start2 && context_cache.context == context_none) { context_cache.context = context_block_comment; assert (context_cache.style != comment_style_none); } else if (context_cache.ccontext == ccontext_none && context_cache.context == context_block_comment) { context_cache.context = context_none; } } context_cache.needs_its_head_reexamined = 0; unbind_to (spec); } static Lisp_Object context_to_symbol (enum syntactic_context context) { switch (context) { case context_none: return Qnil; case context_string: return Qstring; case context_comment: return Qcomment; case context_block_comment: return Qblock_comment; case context_generic_comment: return Qblock_comment; case context_generic_string: return Qstring; default: ABORT (); return Qnil; /* suppress compiler warning */ } } DEFUN ("buffer-syntactic-context", Fbuffer_syntactic_context, 0, 1, 0, /* Return the syntactic context of BUFFER at point. If BUFFER is nil or omitted, the current buffer is assumed. The returned value is one of the following symbols: nil ; meaning no special interpretation string ; meaning point is within a string comment ; meaning point is within a line comment block-comment ; meaning point is within a block comment See also the function `buffer-syntactic-context-depth', which returns the current nesting-depth within all parenthesis-syntax delimiters and the function `syntactically-sectionize', which will map a function over each syntactic context in a region. WARNING: this may alter match-data. */ (buffer)) { /* This function can GC */ struct buffer *buf = decode_buffer (buffer, 0); find_context (buf, BUF_PT (buf)); return context_to_symbol (context_cache.context); } DEFUN ("buffer-syntactic-context-depth", Fbuffer_syntactic_context_depth, 0, 1, 0, /* Return the depth within all parenthesis-syntax delimiters at point. If BUFFER is nil or omitted, the current buffer is assumed. WARNING: this may alter match-data. */ (buffer)) { /* This function can GC */ struct buffer *buf = decode_buffer (buffer, 0); find_context (buf, BUF_PT (buf)); return make_fixnum (context_cache.depth); } DEFUN ("syntactically-sectionize", Fsyntactically_sectionize, 3, 4, 0, /* Call FUNCTION for each contiguous syntactic context in the region. Call the given function with four arguments: the start and end of the region, a symbol representing the syntactic context, and the current depth (as returned by the functions `buffer-syntactic-context' and `buffer-syntactic-context-depth'). When this function is called, the current buffer will be set to BUFFER. WARNING: this may alter match-data. */ (function, start, end, buffer)) { /* This function can GC */ Charbpos s, pt, e; int edepth; enum syntactic_context this_context; Lisp_Object extent = Qnil; struct gcpro gcpro1; struct buffer *buf = decode_buffer (buffer, 0); get_buffer_range_char (buf, start, end, &s, &e, 0); pt = s; find_context (buf, pt); GCPRO1 (extent); while (pt < e) { Charbpos estart, eend; /* skip over "blank" areas, and bug out at end-of-buffer. */ while (context_cache.context == context_none) { pt++; if (pt >= e) goto DONE_LABEL; find_context (buf, pt); } /* We've found a non-blank area; keep going until we reach its end */ this_context = context_cache.context; estart = pt; /* Minor kludge: consider the comment-start character(s) a part of the comment. */ if (this_context == context_block_comment && context_cache.ccontext == ccontext_start2) estart -= 2; else if (this_context == context_comment || this_context == context_generic_comment ) estart -= 1; edepth = context_cache.depth; while (context_cache.context == this_context && pt < e) { pt++; find_context (buf, pt); } eend = pt; /* Minor kludge: consider the character which terminated the comment a part of the comment. */ if ((this_context == context_block_comment || this_context == context_comment || this_context == context_generic_comment ) && pt < e) eend++; if (estart == eend) continue; /* Make sure not to pass in values that are outside the actual bounds of this function. */ call4_in_buffer (buf, function, make_fixnum (max (s, estart)), make_fixnum (eend == e ? e : eend - 1), context_to_symbol (this_context), make_fixnum (edepth)); } DONE_LABEL: UNGCPRO; return Qnil; } void syms_of_font_lock (void) { DEFSYMBOL (Qcomment); DEFSYMBOL (Qblock_comment); DEFSYMBOL (Qbeginning_of_defun); DEFSUBR (Fbuffer_syntactic_context); DEFSUBR (Fbuffer_syntactic_context_depth); DEFSUBR (Fsyntactically_sectionize); } void reinit_vars_of_font_lock (void) { xzero (context_cache); xzero (bol_context_cache); } void vars_of_font_lock (void) { } #endif /* USE_C_FONT_LOCK */