comparison src/redisplay.c @ 2367:ecf1ebac70d8

[xemacs-hg @ 2004-11-04 23:05:23 by ben] commit mega-patch configure.in: Turn off -Winline and -Wchar-subscripts. Use the right set of cflags when compiling modules. Rewrite ldap configuration to separate the inclusion of lber (needed in recent Cygwin) from the basic checks for the needed libraries. add a function for MAKE_JUNK_C; initially code was added to generate xemacs.def using this, but it will need to be rewritten. add an rm -f for junk.c to avoid weird Cygwin bug with cp -f onto an existing file. Sort list of auto-detected functions and eliminate unused checks for stpcpy, setlocale and getwd. Add autodetection of Cygwin scanf problems BETA: Rewrite section on configure to indicate what flags are important and what not. digest-doc.c, make-dump-id.c, profile.c, sorted-doc.c: Add proper decls for main(). make-msgfile.c: Document that this is old junk. Move proposal to text.c. make-msgfile.lex: Move proposal to text.c. make-mswin-unicode.pl: Convert error-generating code so that the entire message will be seen as a single unrecognized token. mule/mule-ccl.el: Update docs. lispref/mule.texi: Update CCL docs. ldap/eldap.c: Mule-ize. Use EXTERNAL_LIST_LOOP_2 instead of deleted EXTERNAL_LIST_LOOP. * XEmacs 21.5.18 "chestnut" is released. --------------------------------------------------------------- MULE-RELATED WORK: --------------------------------------------------------------- --------------------------- byte-char conversion --------------------------- buffer.c, buffer.h, insdel.c, text.c: Port FSF algorithm for byte-char conversion, replacing broken previous version. Track the char position of the gap. Add functions to do char-byte conversion downwards as well as upwards. Move comments about algorithm workings to internals manual. --------------------------- work on types --------------------------- alloc.c, console-x-impl.h, dump-data.c, dump-data.h, dumper.c, dialog-msw.c, dired-msw.c, doc.c, editfns.c, esd.c, event-gtk.h, event-msw.c, events.c, file-coding.c, file-coding.h, fns.c, glyphs-eimage.c, glyphs-gtk.c, glyphs-msw.c, glyphs-shared.c, glyphs-x.c, glyphs.c, glyphs.h, gui.c, hpplay.c, imgproc.c, intl-win32.c, lrecord.h, lstream.c, keymap.c, lisp.h, libsst.c, linuxplay.c, miscplay.c, miscplay.h, mule-coding.c, nas.c, nt.c, ntheap.c, ntplay.c, objects-msw.c, objects-tty.c, objects-x.c, print.c, process-nt.c, process.c, redisplay.h, select-common.h, select-gtk.c, select-x.c, sgiplay.c, sound.c, sound.h, sunplay.c, sysfile.h, sysdep.c, syswindows.h, text.c, unexnt.c, win32.c, xgccache.c: Further work on types. This creates a full set of types for all the basic semantics of `char' that I have so far identified, so that its semantics can always be identified for the purposes of proper Mule-safe code, and the raw use of `char' always avoided. (1) More type renaming, for consistency of naming. Char_ASCII -> Ascbyte UChar_ASCII -> UAscbyte Char_Binary -> CBinbyte UChar_Binary -> Binbyte SChar_Binary -> SBinbyte (2) Introduce Rawbyte, CRawbyte, Boolbyte, Chbyte, UChbyte, and Bitbyte and use them. (3) New types Itext, Wexttext and Textcount for separating out the concepts of bytes and textual units (different under UTF-16 and UTF-32, which are potential internal encodings). (4) qxestr*_c -> qxestr*_ascii. lisp.h: New; goes with other qxe() functions. #### Maybe goes in a different section. lisp.h: Group generic int-type defs together with EMACS_INT defs. lisp.h: * lisp.h (WEXTTEXT_IS_WIDE) New defns. lisp.h: New type to replace places where int occurs as a boolean. It's signed because occasionally people may want to use -1 as an error value, and because unsigned ints are viral -- see comments in the internals manual against using them. dynarr.c: int -> Bytecount. --------------------------- Mule-izing --------------------------- device-x.c: Partially Mule-ize. dumper.c, dumper.h: Mule-ize. Use Rawbyte. Use stderr_out not printf. Use wext_*(). sysdep.c, syswindows.h, text.c: New Wexttext API for manipulation of external text that may be Unicode (e.g. startup code under Windows). emacs.c: Mule-ize. Properly deal with argv in external encoding. Use wext_*() and Wexttext. Use Rawbyte. #if 0 some old junk on SCO that is unlikely to be correct. Rewrite allocation code in run-temacs. emacs.c, symsinit.h, win32.c: Rename win32 init function and call it even earlier, to initialize mswindows_9x_p even earlier, for use in startup code (XEUNICODE_P). process.c: Use _wenviron not environ under Windows, to get Unicode environment variables. event-Xt.c: Mule-ize drag-n-drop related stuff. dragdrop.c, dragdrop.h, frame-x.c: Mule-ize. text.h: Add some more stand-in defines for particular kinds of conversion; use in Mule-ization work in frame-x.c etc. --------------------------- Freshening --------------------------- intl-auto-encap-win32.c, intl-auto-encap-win32.h: Regenerate. --------------------------- Unicode-work --------------------------- intl-win32.c, syswindows.h: Factor out common options to MultiByteToWideChar and WideCharToMultiByte. Add convert_unicode_to_multibyte_malloc() and convert_unicode_to_multibyte_dynarr() and use. Add stuff for alloca() conversion of multibyte/unicode. alloc.c: Use dfc_external_data_len() in case of unicode coding system. alloc.c, mule-charset.c: Don't zero out and reinit charset Unicode tables. This fucks up dump-time loading. Anyway, either we load them at dump time or run time, never both. unicode.c: Dump the blank tables as well. --------------------------------------------------------------- DOCUMENTATION, MOSTLY MULE-RELATED: --------------------------------------------------------------- EmacsFrame.c, emodules.c, event-Xt.c, fileio.c, input-method-xlib.c, mule-wnnfns.c, redisplay-gtk.c, redisplay-tty.c, redisplay-x.c, regex.c, sysdep.c: Add comment about Mule work needed. text.h: Add more documentation describing why DFC routines were not written to return their value. Add some other DFC documentation. console-msw.c, console-msw.h: Add pointer to docs in win32.c. emacs.c: Add comments on sources of doc info. text.c, charset.h, unicode.c, intl-win32.c, intl-encap-win32.c, text.h, file-coding.c, mule-coding.c: Collect background comments and related to text matters and internationalization, and proposals for work to be done, in text.c or Internals manual, stuff related to specific textual API's in text.h, and stuff related to internal implementation of Unicode conversion in unicode.c. Put lots of pointers to the comments to make them easier to find. s/mingw32.h, s/win32-common.h, s/win32-native.h, s/windowsnt.h, win32.c: Add bunches of new documentation on the different kinds of builds and environments under Windows and how they work. Collect this info in win32.c. Add pointers to these docs in the relevant s/* files. emacs.c: Document places with long comments. Remove comment about exiting, move to internals manual, put in pointer. event-stream.c: Move docs about event queues and focus to internals manual, put in pointer. events.h: Move docs about event stream callbacks to internals manual, put in pointer. profile.c, redisplay.c, signal.c: Move documentation to the Internals manual. process-nt.c: Add pointer to comment in win32-native.el. lisp.h: Add comments about some comment conventions. lisp.h: Add comment about the second argument. device-msw.c, redisplay-msw.c: @@#### comments are out-of-date. --------------------------------------------------------------- PDUMP WORK (MOTIVATED BY UNICODE CHANGES) --------------------------------------------------------------- alloc.c, buffer.c, bytecode.c, console-impl.h, console.c, device.c, dumper.c, lrecord.h, elhash.c, emodules.h, events.c, extents.c, frame.c, glyphs.c, glyphs.h, mule-charset.c, mule-coding.c, objects.c, profile.c, rangetab.c, redisplay.c, specifier.c, specifier.h, window.c, lstream.c, file-coding.h, file-coding.c: PDUMP: Properly implement dump_add_root_block(), which never worked before, and is necessary for dumping Unicode tables. Pdump name changes for accuracy: XD_STRUCT_PTR -> XD_BLOCK_PTR. XD_STRUCT_ARRAY -> XD_BLOCK_ARRAY. XD_C_STRING -> XD_ASCII_STRING. *_structure_* -> *_block_*. lrecord.h: some comments added about dump_add_root_block() vs dump_add_root_block_ptr(). extents.c: remove incorrect comment about pdump problems with gap array. --------------------------------------------------------------- ALLOCATION --------------------------------------------------------------- abbrev.c, alloc.c, bytecode.c, casefiddle.c, device-msw.c, device-x.c, dired-msw.c, doc.c, doprnt.c, dragdrop.c, editfns.c, emodules.c, file-coding.c, fileio.c, filelock.c, fns.c, glyphs-eimage.c, glyphs-gtk.c, glyphs-msw.c, glyphs-x.c, gui-msw.c, gui-x.c, imgproc.c, intl-win32.c, lread.c, menubar-gtk.c, menubar.c, nt.c, objects-msw.c, objects-x.c, print.c, process-nt.c, process-unix.c, process.c, realpath.c, redisplay.c, search.c, select-common.c, symbols.c, sysdep.c, syswindows.h, text.c, text.h, ui-byhand.c: New macros {alloca,xnew}_{itext,{i,ext,raw,bin,asc}bytes} for more convenient allocation of these commonly requested items. Modify functions to use alloca_ibytes, alloca_array, alloca_extbytes, xnew_ibytes, etc. also XREALLOC_ARRAY, xnew. alloc.c: Rewrite the allocation functions to factor out repeated code. Add assertions for freeing dumped data. lisp.h: Moved down and consolidated with other allocation stuff. lisp.h, dynarr.c: New functions for allocation that's very efficient when mostly in LIFO order. lisp.h, text.c, text.h: Factor out some stuff for general use by alloca()-conversion funs. text.h, lisp.h: Fill out convenience routines for allocating various kinds of bytes and put them in lisp.h. Use them in place of xmalloc(), ALLOCA(). text.h: Fill out the convenience functions so the _MALLOC() kinds match the alloca() kinds. --------------------------------------------------------------- ERROR-CHECKING --------------------------------------------------------------- text.h: Create ASSERT_ASCTEXT_ASCII() and ASSERT_ASCTEXT_ASCII_LEN() from similar Eistring checkers and change the Eistring checkers to use them instead. --------------------------------------------------------------- MACROS IN LISP.H --------------------------------------------------------------- lisp.h: Redo GCPRO declarations. Create a "base" set of functions that can be used to generate any kind of gcpro sets -- regular, ngcpro, nngcpro, private ones used in GC_EXTERNAL_LIST_LOOP_2. buffer.c, callint.c, chartab.c, console-msw.c, device-x.c, dialog-msw.c, dired.c, extents.c, ui-gtk.c, rangetab.c, nt.c, mule-coding.c, minibuf.c, menubar-msw.c, menubar.c, menubar-gtk.c, lread.c, lisp.h, gutter.c, glyphs.c, glyphs-widget.c, fns.c, fileio.c, file-coding.c, specifier.c: Eliminate EXTERNAL_LIST_LOOP, which does not check for circularities. Use EXTERNAL_LIST_LOOP_2 instead or EXTERNAL_LIST_LOOP_3 or EXTERNAL_PROPERTY_LIST_LOOP_3 or GC_EXTERNAL_LIST_LOOP_2 (new macro). Removed/redid comments on EXTERNAL_LIST_LOOP. --------------------------------------------------------------- SPACING FIXES --------------------------------------------------------------- callint.c, hftctl.c, number-gmp.c, process-unix.c: Spacing fixes. --------------------------------------------------------------- FIX FOR GEOMETRY PROBLEM IN FIRST FRAME --------------------------------------------------------------- unicode.c: Add workaround for newlib bug in sscanf() [should be fixed by release 1.5.12 of Cygwin]. toolbar.c: bug fix for problem of initial frame being 77 chars wide on Windows. will be overridden by my other ws. --------------------------------------------------------------- FIX FOR LEAKING PROCESS HANDLES: --------------------------------------------------------------- process-nt.c: Fixes for leaking handles. Inspired by work done by Adrian Aichner <adrian@xemacs.org>. --------------------------------------------------------------- FIX FOR CYGWIN BUG (Unicode-related): --------------------------------------------------------------- unicode.c: Add workaround for newlib bug in sscanf() [should be fixed by release 1.5.12 of Cygwin]. --------------------------------------------------------------- WARNING FIXES: --------------------------------------------------------------- console-stream.c: `reinit' is unused. compiler.h, event-msw.c, frame-msw.c, intl-encap-win32.c, text.h: Add stuff to deal with ANSI-aliasing warnings I got. regex.c: Gather includes together to avoid warning. --------------------------------------------------------------- CHANGES TO INITIALIZATION ROUTINES: --------------------------------------------------------------- buffer.c, emacs.c, console.c, debug.c, device-x.c, device.c, dragdrop.c, emodules.c, eval.c, event-Xt.c, event-gtk.c, event-msw.c, event-stream.c, event-tty.c, events.c, extents.c, faces.c, file-coding.c, fileio.c, font-lock.c, frame-msw.c, glyphs-widget.c, glyphs.c, gui-x.c, insdel.c, lread.c, lstream.c, menubar-gtk.c, menubar-x.c, minibuf.c, mule-wnnfns.c, objects-msw.c, objects.c, print.c, scrollbar-x.c, search.c, select-x.c, text.c, undo.c, unicode.c, window.c, symsinit.h: Call reinit_*() functions directly from emacs.c, for clarity. Factor out some redundant init code. Move disallowed stuff that had crept into vars_of_glyphs() into complex_vars_of_glyphs(). Call init_eval_semi_early() from eval.c not in the middle of vars_of_() in emacs.c since there should be no order dependency in the latter calls. --------------------------------------------------------------- ARMAGEDDON: --------------------------------------------------------------- alloc.c, emacs.c, lisp.h, print.c: Rename inhibit_non_essential_printing_operations to inhibit_non_essential_conversion_operations. text.c: Assert on !inhibit_non_essential_conversion_operations. console-msw.c, print.c: Don't do conversion in SetConsoleTitle or FindWindow to avoid problems during armageddon. Put #errors for NON_ASCII_INTERNAL_FORMAT in places where problems would arise. --------------------------------------------------------------- CHANGES TO THE BUILD PROCEDURE: --------------------------------------------------------------- config.h.in, s/cxux.h, s/usg5-4-2.h, m/powerpc.h: Add comment about correct ordering of this file. Rearrange everything to follow this -- put all #undefs together and before the s&m files. Add undefs for HAVE_ALLOCA, C_ALLOCA, BROKEN_ALLOCA_IN_FUNCTION_CALLS, STACK_DIRECTION. Remove unused HAVE_STPCPY, HAVE_GETWD, HAVE_SETLOCALE. m/gec63.h: Deleted; totally broken, not used at all, not in FSF. m/7300.h, m/acorn.h, m/alliant-2800.h, m/alliant.h, m/altos.h, m/amdahl.h, m/apollo.h, m/att3b.h, m/aviion.h, m/celerity.h, m/clipper.h, m/cnvrgnt.h, m/convex.h, m/cydra5.h, m/delta.h, m/delta88k.h, m/dpx2.h, m/elxsi.h, m/ews4800r.h, m/gould.h, m/hp300bsd.h, m/hp800.h, m/hp9000s300.h, m/i860.h, m/ibmps2-aix.h, m/ibmrs6000.h, m/ibmrt-aix.h, m/ibmrt.h, m/intel386.h, m/iris4d.h, m/iris5d.h, m/iris6d.h, m/irist.h, m/isi-ov.h, m/luna88k.h, m/m68k.h, m/masscomp.h, m/mg1.h, m/mips-nec.h, m/mips-siemens.h, m/mips.h, m/news.h, m/nh3000.h, m/nh4000.h, m/ns32000.h, m/orion105.h, m/pfa50.h, m/plexus.h, m/pmax.h, m/powerpc.h, m/pyrmips.h, m/sequent-ptx.h, m/sequent.h, m/sgi-challenge.h, m/symmetry.h, m/tad68k.h, m/tahoe.h, m/targon31.h, m/tekxd88.h, m/template.h, m/tower32.h, m/tower32v3.h, m/ustation.h, m/vax.h, m/wicat.h, m/xps100.h: Delete C_ALLOCA, HAVE_ALLOCA, STACK_DIRECTION, BROKEN_ALLOCA_IN_FUNCTION_CALLS. All of this is auto-detected. When in doubt, I followed recent FSF sources, which also have these things deleted.
author ben
date Thu, 04 Nov 2004 23:08:28 +0000
parents 04bc9d2f42c7
children 3d8143fc88e1
comparison
equal deleted inserted replaced
2366:2a392e0c390a 2367:ecf1ebac70d8
520 static const struct sized_memory_description rune_dglyph_description = { 520 static const struct sized_memory_description rune_dglyph_description = {
521 sizeof (struct rune_dglyph), rune_dglyph_description_1 521 sizeof (struct rune_dglyph), rune_dglyph_description_1
522 }; 522 };
523 523
524 static const struct memory_description rune_object_description_1[] = { 524 static const struct memory_description rune_object_description_1[] = {
525 { XD_STRUCT_ARRAY, RUNE_DGLYPH, 1, &rune_dglyph_description }, 525 { XD_BLOCK_ARRAY, RUNE_DGLYPH, 1, &rune_dglyph_description },
526 { XD_END } 526 { XD_END }
527 }; 527 };
528 528
529 static const struct sized_memory_description rune_object_description = { 529 static const struct sized_memory_description rune_object_description = {
530 0, rune_object_description_1 530 0, rune_object_description_1
551 sizeof (rune_dynarr), 551 sizeof (rune_dynarr),
552 rune_dynarr_description_1 552 rune_dynarr_description_1
553 }; 553 };
554 554
555 static const struct memory_description display_block_description_1[] = { 555 static const struct memory_description display_block_description_1[] = {
556 { XD_STRUCT_PTR, offsetof (display_block, runes), 556 { XD_BLOCK_PTR, offsetof (display_block, runes),
557 1, &rune_dynarr_description }, 557 1, &rune_dynarr_description },
558 { XD_END } 558 { XD_END }
559 }; 559 };
560 560
561 static const struct sized_memory_description display_block_description = { 561 static const struct sized_memory_description display_block_description = {
593 sizeof (glyph_block_dynarr), 593 sizeof (glyph_block_dynarr),
594 glyph_block_dynarr_description_1 594 glyph_block_dynarr_description_1
595 }; 595 };
596 596
597 static const struct memory_description display_line_description_1[] = { 597 static const struct memory_description display_line_description_1[] = {
598 { XD_STRUCT_PTR, offsetof (display_line, display_blocks), 598 { XD_BLOCK_PTR, offsetof (display_line, display_blocks),
599 1, &display_block_dynarr_description }, 599 1, &display_block_dynarr_description },
600 { XD_STRUCT_PTR, offsetof (display_line, left_glyphs), 600 { XD_BLOCK_PTR, offsetof (display_line, left_glyphs),
601 1, &glyph_block_dynarr_description }, 601 1, &glyph_block_dynarr_description },
602 { XD_STRUCT_PTR, offsetof (display_line, right_glyphs), 602 { XD_BLOCK_PTR, offsetof (display_line, right_glyphs),
603 1, &glyph_block_dynarr_description }, 603 1, &glyph_block_dynarr_description },
604 { XD_END } 604 { XD_END }
605 }; 605 };
606 606
607 static const struct sized_memory_description display_line_description = { 607 static const struct sized_memory_description display_line_description = {
1567 && STRINGP (XCAR (XCDR (entry)))) 1567 && STRINGP (XCAR (XCDR (entry))))
1568 { 1568 {
1569 Lisp_Object format = XCAR (XCDR (entry)); 1569 Lisp_Object format = XCAR (XCDR (entry));
1570 Bytebpos len = XSTRING_LENGTH (format); 1570 Bytebpos len = XSTRING_LENGTH (format);
1571 Ibyte *src = XSTRING_DATA (format), *end = src + len; 1571 Ibyte *src = XSTRING_DATA (format), *end = src + len;
1572 Ibyte *result = alloca_array (Ibyte, len); 1572 Ibyte *result = alloca_ibytes (len);
1573 Ibyte *dst = result; 1573 Ibyte *dst = result;
1574 1574
1575 while (src < end) 1575 while (src < end)
1576 { 1576 {
1577 Ichar c = itext_ichar (src); 1577 Ichar c = itext_ichar (src);
2142 /* The variable ctl-arrow allows the user to specify what characters 2142 /* The variable ctl-arrow allows the user to specify what characters
2143 can actually be displayed and which octal should be used for. 2143 can actually be displayed and which octal should be used for.
2144 #### This variable should probably have some rethought done to 2144 #### This variable should probably have some rethought done to
2145 it. 2145 it.
2146 2146
2147 #### It would also be really nice if you could specify that 2147 See also
2148 the characters come out in hex instead of in octal. Mule 2148
2149 does that by adding a ctl-hexa variable similar to ctl-arrow, 2149 (Info-goto-node "(internals)Future Work -- Display Tables")
2150 but that's bogus -- we need a more general solution. I 2150
2151 think you need to extend the concept of display tables 2151 */
2152 into a more general conversion mechanism. Ideally you
2153 could specify a Lisp function that converts characters,
2154 but this violates the Second Golden Rule and besides would
2155 make things way way way way slow.
2156
2157 So instead, we extend the display-table concept, which was
2158 historically limited to 256-byte vectors, to one of the
2159 following:
2160
2161 a) A 256-entry vector, for backward compatibility;
2162 b) char-table, mapping characters to values;
2163 c) range-table, mapping ranges of characters to values;
2164 d) a list of the above.
2165
2166 The (d) option allows you to specify multiple display tables
2167 instead of just one. Each display table can specify conversions
2168 for some characters and leave others unchanged. The way the
2169 character gets displayed is determined by the first display table
2170 with a binding for that character. This way, you could call a
2171 function `enable-hex-display' that adds a hex display-table to
2172 the list of display tables for the current buffer.
2173
2174 #### ...not yet implemented... Also, we extend the concept of
2175 "mapping" to include a printf-like spec. Thus you can make all
2176 extended characters show up as hex with a display table like
2177 this:
2178
2179 #s(range-table data ((256 524288) (format "%x")))
2180
2181 Since more than one display table is possible, you have
2182 great flexibility in mapping ranges of characters. */
2183 Ichar printable_min = (CHAR_OR_CHAR_INTP (b->ctl_arrow) 2152 Ichar printable_min = (CHAR_OR_CHAR_INTP (b->ctl_arrow)
2184 ? XCHAR_OR_CHAR_INT (b->ctl_arrow) 2153 ? XCHAR_OR_CHAR_INT (b->ctl_arrow)
2185 : ((EQ (b->ctl_arrow, Qt) || EQ (b->ctl_arrow, Qnil)) 2154 : ((EQ (b->ctl_arrow, Qt) || EQ (b->ctl_arrow, Qnil))
2186 ? 255 : 160)); 2155 ? 255 : 160));
2187 2156
7732 mark_glyph_block_dynarr (dl->right_glyphs); 7701 mark_glyph_block_dynarr (dl->right_glyphs);
7733 } 7702 }
7734 } 7703 }
7735 7704
7736 7705
7737 /***************************************************************************** 7706
7738 Line Start Cache Description and Rationale 7707 /*
7739 7708
7740 The traditional scrolling code in Emacs breaks in a variable height world. 7709 Info on line-start cache:
7741 It depends on the key assumption that the number of lines that can be 7710
7742 displayed at any given time is fixed. This led to a complete separation 7711 (Info-goto-node "(internals)Line Start Cache")
7743 of the scrolling code from the redisplay code. In order to fully support 7712 */
7744 variable height lines, the scrolling code must actually be tightly
7745 integrated with redisplay. Only redisplay can determine how many lines
7746 will be displayed on a screen for any given starting point.
7747
7748 What is ideally wanted is a complete list of the starting buffer position
7749 for every possible display line of a buffer along with the height of that
7750 display line. Maintaining such a full list would be very expensive. We
7751 settle for having it include information for all areas which we happen to
7752 generate anyhow (i.e. the region currently being displayed) and for those
7753 areas we need to work with.
7754
7755 In order to ensure that the cache accurately represents what redisplay
7756 would actually show, it is necessary to invalidate it in many situations.
7757 If the buffer changes, the starting positions may no longer be correct.
7758 If a face or an extent has changed then the line heights may have altered.
7759 These events happen frequently enough that the cache can end up being
7760 constantly disabled. With this potentially constant invalidation when is
7761 the cache ever useful?
7762
7763 Even if the cache is invalidated before every single usage, it is
7764 necessary. Scrolling often requires knowledge about display lines which
7765 are actually above or below the visible region. The cache provides a
7766 convenient light-weight method of storing this information for multiple
7767 display regions. This knowledge is necessary for the scrolling code to
7768 always obey the First Golden Rule of Redisplay.
7769
7770 If the cache already contains all of the information that the scrolling
7771 routines happen to need so that it doesn't have to go generate it, then we
7772 are able to obey the Third Golden Rule of Redisplay. The first thing we
7773 do to help out the cache is to always add the displayed region. This
7774 region had to be generated anyway, so the cache ends up getting the
7775 information basically for free. In those cases where a user is simply
7776 scrolling around viewing a buffer there is a high probability that this is
7777 sufficient to always provide the needed information. The second thing we
7778 can do is be smart about invalidating the cache.
7779
7780 TODO -- Be smart about invalidating the cache. Potential places:
7781
7782 + Insertions at end-of-line which don't cause line-wraps do not alter the
7783 starting positions of any display lines. These types of buffer
7784 modifications should not invalidate the cache. This is actually a large
7785 optimization for redisplay speed as well.
7786
7787 + Buffer modifications frequently only affect the display of lines at and
7788 below where they occur. In these situations we should only invalidate
7789 the part of the cache starting at where the modification occurs.
7790
7791 In case you're wondering, the Second Golden Rule of Redisplay is not
7792 applicable.
7793 ****************************************************************************/
7794 7713
7795 /* This will get used quite a bit so we don't want to be constantly 7714 /* This will get used quite a bit so we don't want to be constantly
7796 allocating and freeing it. */ 7715 allocating and freeing it. */
7797 static line_start_cache_dynarr *internal_cache; 7716 static line_start_cache_dynarr *internal_cache;
7798 7717