Fixed tags file corruption on Windows!

 * Fixed tags file corruption on Windows: It turns out that the function
   readfile() accepts CR+NL line endings and just strips CR characters,
   however the writefile() function doesn't write CR+NL but just NL.
   Manually adding the CR characters to the end of each line before
   writing the tags file solves the corruption bug.

 * The headers and entries in tags files are now properly separated from
   each other while rewriting the tags file to filter expired entries.

 * Don't bother trying to filter expired tags when the tags file doesn't
   reference the current filename at all (improves performance a bit).

 * Fixed a buggy easytags#file_has_tags() call in easytags#autoload()
   that made the plug-in always scan each edited file at least once.

 * Changed folds to provide basic outline of function categories.

 * Restructured definitions for default configuration of dynamic syntax
   highlighting support so definitions don't all have to be indented.

Sorry about the large diff, this version took a few days of
experimentation to build which means lots of little changes.

2 files changed, 201 insertions, 161 deletions

diff --git a/autoload.vim b/autoload.vim
index 706f450..ac48f4a 100644
--- a/autoload.vim
+++ b/autoload.vim
@@ -1,12 +1,14 @@
 " Vim script
 " Maintainer: Peter Odding <peter@peterodding.com>
-" Last Change: June 10, 2010
+" Last Change: June 13, 2010
 " URL: http://peterodding.com/code/vim/easytags
 
-function! easytags#autoload() " {{{1
+" Public interface through (automatic) commands. {{{1
+
+function! easytags#autoload() " {{{2
   try
     " Update the entries for the current file in the global tags file?
-    let pathname = expand('%')
+    let pathname = s:resolve(expand('%:p'))
     let tags_outdated = getftime(pathname) > getftime(easytags#get_tagsfile())
     if tags_outdated || !easytags#file_has_tags(pathname)
       UpdateTags
@@ -30,32 +32,35 @@ function! easytags#autoload() " {{{1
   endtry
 endfunction
 
-function! easytags#update_cmd(filter_invalid_tags) " {{{1
+function! easytags#update_cmd(filter_invalid_tags) " {{{2
   try
+    let filename = s:resolve(expand('%:p'))
     let ft_supported = index(easytags#supported_filetypes(), &ft) >= 0
     let ft_ignored = g:easytags_ignored_filetypes != '' && &ft =~ g:easytags_ignored_filetypes
     if (ft_supported && !ft_ignored) || a:filter_invalid_tags
       let start = xolox#timer#start()
       let tagsfile = easytags#get_tagsfile()
-      let filename = s:resolve(expand('%:p'))
       let command = [g:easytags_cmd, '-f', shellescape(tagsfile), '--fields=+l']
       if filereadable(tagsfile)
         call add(command, '-a')
-        let lines = readfile(tagsfile)
-        call s:update_tagged_files(lines)
-        let filters = []
-        if ft_supported && !ft_ignored
-          let filename_pattern = '\t' . xolox#escape#pattern(filename) . '\t'
-          call add(filters, 'v:val !~ filename_pattern')
-        endif
-        if a:filter_invalid_tags
-          call add(filters, 'filereadable(get(split(v:val, "\t"), 1))')
-        endif
-        let filter = 'v:val =~ "^!_TAG_" || (' . join(filters, ' && ') . ')'
-        let filtered = filter(copy(lines), filter)
-        if len(lines) != len(filtered)
-          if writefile(filtered, tagsfile) != 0
-            throw "Failed to write filtered tags file!"
+        let filter_file_tags = easytags#file_has_tags(filename)
+        if a:filter_invalid_tags || filter_file_tags
+          let [header, entries] = easytags#read_tagsfile(tagsfile)
+          let num_entries = len(entries)
+          call s:set_tagged_files(entries)
+          let filters = []
+          if ft_supported && !ft_ignored && filter_file_tags
+            let filename_pattern = '\t' . xolox#escape#pattern(filename) . '\t'
+            call add(filters, 'v:val !~ filename_pattern')
+          endif
+          if a:filter_invalid_tags
+            call add(filters, 'filereadable(get(split(v:val, "\t"), 1))')
+          endif
+          call filter(entries, join(filters, ' && '))
+          if len(entries) != num_entries
+            if !easytags#write_tagsfile(tagsfile, header, entries)
+              throw "Failed to write filtered tags file!"
+            endif
           endif
         endif
       endif
@@ -77,21 +82,7 @@ function! easytags#update_cmd(filter_invalid_tags) " {{{1
   endtry
 endfunction
 
-function! easytags#supported_filetypes() " {{{1
-  if !exists('s:supported_filetypes')
-    let start = xolox#timer#start()
-    let listing = system(g:easytags_cmd . ' --list-languages')
-    if v:shell_error
-      throw "Failed to get Exuberant Ctags language mappings!"
-    endif
-    let s:supported_filetypes = split(listing, '\n')
-    call map(s:supported_filetypes, 'easytags#to_vim_ft(v:val)')
-    call xolox#timer#stop(start, "easytags.vim: Parsed language mappings in %s second(s)")
-  endif
-  return s:supported_filetypes
-endfunction
-
-function! easytags#highlight_cmd() " {{{1
+function! easytags#highlight_cmd() " {{{2
   try
     if exists('g:syntax_on') && has_key(s:tagkinds, &ft)
       let start = xolox#timer#start()
@@ -124,7 +115,62 @@ function! easytags#highlight_cmd() " {{{1
   endtry
 endfunction
 
-function! easytags#get_tagsfile() " {{{1
+" Public supporting functions (might be useful to others). {{{1
+
+function! easytags#supported_filetypes() " {{{2
+  if !exists('s:supported_filetypes')
+    let start = xolox#timer#start()
+    let listing = system(g:easytags_cmd . ' --list-languages')
+    if v:shell_error
+      throw "Failed to get Exuberant Ctags language mappings!"
+    endif
+    let s:supported_filetypes = split(listing, '\n')
+    call map(s:supported_filetypes, 'easytags#to_vim_ft(v:val)')
+    call xolox#timer#stop(start, "easytags.vim: Parsed language mappings in %s second(s)")
+  endif
+  return s:supported_filetypes
+endfunction
+
+function! easytags#read_tagsfile(tagsfile) " {{{2
+  let lines = readfile(a:tagsfile)
+  let header = []
+  while lines != [] && lines[0] =~# '^!_TAG_'
+    call insert(header, remove(lines, 0))
+  endwhile
+  while lines != [] && lines[-1] == ''
+    call remove(lines, -1)
+  endwhile
+  return [header, lines]
+endfunction
+
+function! easytags#write_tagsfile(tagsfile, header, entries) " {{{2
+  let lines = []
+  if has('win32') || has('win64')
+    for line in a:header
+      call add(lines, line . "\r")
+    endfor
+    for entry in a:entries
+      call add(lines, entry . "\r")
+    endfor
+  else
+    call extend(lines, a:header)
+    call extend(lines, a:entries)
+  endif
+  return writefile(lines, a:tagsfile) == 0
+endfunction
+
+function! easytags#file_has_tags(filename) " {{{2
+  call s:cache_tagged_files()
+  return has_key(s:tagged_files, s:resolve(a:filename))
+endfunction
+
+function! easytags#add_tagged_file(filename) " {{{2
+  call s:cache_tagged_files()
+  let filename = s:resolve(a:filename)
+  let s:tagged_files[filename] = 1
+endfunction
+
+function! easytags#get_tagsfile() " {{{2
   let tagsfile = expand(g:easytags_file)
   if filereadable(tagsfile) && filewritable(tagsfile) != 1
     let message = "The tags file isn't writable! (%s)"
@@ -133,7 +179,9 @@ function! easytags#get_tagsfile() " {{{1
   return tagsfile
 endfunction
 
-function! easytags#define_tagkind(object) " {{{1
+" Public API for file-type specific dynamic syntax highlighting. {{{1
+
+function! easytags#define_tagkind(object) " {{{2
   if !has_key(a:object, 'pattern_prefix')
     let a:object.pattern_prefix = '\C\<'
   endif
@@ -146,12 +194,12 @@ function! easytags#define_tagkind(object) " {{{1
   call add(s:tagkinds[a:object.filetype], a:object)
 endfunction
 
-function! easytags#map_filetypes(vim_ft, ctags_ft) " {{{1
+function! easytags#map_filetypes(vim_ft, ctags_ft) " {{{2
   call add(s:vim_filetypes, a:vim_ft)
   call add(s:ctags_filetypes, a:ctags_ft)
 endfunction
 
-function! easytags#alias_filetypes(...) " {{{1
+function! easytags#alias_filetypes(...) " {{{2
   for type in a:000
     if !has_key(s:aliases, type)
       let s:aliases[type] = {}
@@ -173,13 +221,13 @@ function! easytags#alias_filetypes(...) " {{{1
   endfor
 endfunction
 
-function! easytags#to_vim_ft(ctags_ft) " {{{1
+function! easytags#to_vim_ft(ctags_ft) " {{{2
   let type = tolower(a:ctags_ft)
   let index = index(s:ctags_filetypes, type)
   return index >= 0 ? s:vim_filetypes[index] : type
 endfunction
 
-function! easytags#to_ctags_ft(vim_ft) " {{{1
+function! easytags#to_ctags_ft(vim_ft) " {{{2
   let type = tolower(a:vim_ft)
   let index = index(s:vim_filetypes, type)
   return index >= 0 ? s:ctags_filetypes[index] : type
@@ -187,173 +235,165 @@ endfunction
 
 " Miscellaneous script-local functions. {{{1
 
-function! s:resolve(pathname) " {{{2
+function! s:resolve(filename) " {{{2
   if g:easytags_resolve_links
-    return resolve(a:pathname)
+    return resolve(a:filename)
   else
-    return a:pathname
+    return a:filename
   endif
 endfunction
 
 function! s:cache_tagged_files() " {{{2
   if !exists('s:tagged_files')
     let tagsfile = easytags#get_tagsfile()
-    call s:update_tagged_files(readfile(tagsfile))
+    let [header, entries] = easytags#read_tagsfile(tagsfile)
+    call s:set_tagged_files(entries)
   endif
 endfunction
 
-function! easytags#file_has_tags(pathname) " {{{2
-  call s:cache_tagged_files()
-  return has_key(s:tagged_files, s:resolve(a:pathname))
-endfunction
-
-function! easytags#add_tagged_file(pathname) " {{{2
-  call s:cache_tagged_files()
-  let pathname = s:resolve(a:pathname)
-  let s:tagged_files[pathname] = 1
-endfunction
-
-function! s:update_tagged_files(lines) " {{{2
-  " Update the dictionary of 
+function! s:set_tagged_files(entries) " {{{2
   let s:tagged_files = {}
-  for line in a:lines
-    if line !~ '^!_TAG_'
-      let pathname = matchstr(line, '^[^\t]\+\t\zs[^\t]\+')
-      if pathname != ''
-        let pathname = s:resolve(pathname)
-        let s:tagged_files[pathname] = 1
-      endif
+  for entry in a:entries
+    let filename = matchstr(entry, '^[^\t]\+\t\zs[^\t]\+')
+    if filename != ''
+      let filename = s:resolve(filename)
+      let s:tagged_files[filename] = 1
     endif
   endfor
 endfunction
 
 " Built-in file type & tag kind definitions. {{{1
 
-if !exists('s:tagkinds')
+" Don't bother redefining everything below when this script is sourced again.
+if exists('s:tagkinds')
+  finish
+endif
 
-  let s:vim_filetypes = []
-  let s:ctags_filetypes = []
-  call easytags#map_filetypes('cpp', 'c++')
-  call easytags#map_filetypes('cs', 'c#')
-  call easytags#map_filetypes(exists('filetype_asp') ? filetype_asp : 'aspvbs', 'asp')
+let s:tagkinds = {}
 
-  let s:aliases = {}
-  call easytags#alias_filetypes('c', 'cpp', 'objc', 'objcpp')
+" Define the built-in Vim <=> Ctags file-type mappings.
+let s:vim_filetypes = []
+let s:ctags_filetypes = []
+call easytags#map_filetypes('cpp', 'c++')
+call easytags#map_filetypes('cs', 'c#')
+call easytags#map_filetypes(exists('filetype_asp') ? filetype_asp : 'aspvbs', 'asp')
 
-  let s:tagkinds = {}
+" Define the Vim file-types that are aliased by default.
+let s:aliases = {}
+call easytags#alias_filetypes('c', 'cpp', 'objc', 'objcpp')
 
-  " Enable line continuation.
-  let s:cpo_save = &cpo
-  set cpo&vim
+" Enable line continuation.
+let s:cpo_save = &cpo
+set cpo&vim
 
-  " Lua. {{{2
+" Lua. {{{2
 
-  call easytags#define_tagkind({
-        \ 'filetype': 'lua',
-        \ 'hlgroup': 'luaFunc',
-        \ 'filter': 'get(v:val, "kind") ==# "f"'})
+call easytags#define_tagkind({
+      \ 'filetype': 'lua',
+      \ 'hlgroup': 'luaFunc',
+      \ 'filter': 'get(v:val, "kind") ==# "f"'})
 
-  " C. {{{2
+" C. {{{2
 
-  call easytags#define_tagkind({
-        \ 'filetype': 'c',
-        \ 'hlgroup': 'cType',
-        \ 'filter': 'get(v:val, "kind") =~# "[cgstu]"'})
+call easytags#define_tagkind({
+      \ 'filetype': 'c',
+      \ 'hlgroup': 'cType',
+      \ 'filter': 'get(v:val, "kind") =~# "[cgstu]"'})
 
-  call easytags#define_tagkind({
-        \ 'filetype': 'c',
-        \ 'hlgroup': 'cPreProc',
-        \ 'filter': 'get(v:val, "kind") ==# "d"'})
+call easytags#define_tagkind({
+      \ 'filetype': 'c',
+      \ 'hlgroup': 'cPreProc',
+      \ 'filter': 'get(v:val, "kind") ==# "d"'})
 
-  call easytags#define_tagkind({
-        \ 'filetype': 'c',
-        \ 'hlgroup': 'cFunction',
-        \ 'filter': 'get(v:val, "kind") =~# "[fp]"'})
+call easytags#define_tagkind({
+      \ 'filetype': 'c',
+      \ 'hlgroup': 'cFunction',
+      \ 'filter': 'get(v:val, "kind") =~# "[fp]"'})
 
-  highlight def link cFunction Function
+highlight def link cFunction Function
 
-  " PHP. {{{2
+" PHP. {{{2
 
-  call easytags#define_tagkind({
-        \ 'filetype': 'php',
-        \ 'hlgroup': 'phpFunctions',
-        \ 'filter': 'get(v:val, "kind") ==# "f"'})
+call easytags#define_tagkind({
+      \ 'filetype': 'php',
+      \ 'hlgroup': 'phpFunctions',
+      \ 'filter': 'get(v:val, "kind") ==# "f"'})
 
-  call easytags#define_tagkind({
-        \ 'filetype': 'php',
-        \ 'hlgroup': 'phpClasses',
-        \ 'filter': 'get(v:val, "kind") ==# "c"'})
+call easytags#define_tagkind({
+      \ 'filetype': 'php',
+      \ 'hlgroup': 'phpClasses',
+      \ 'filter': 'get(v:val, "kind") ==# "c"'})
 
-  " Vim script. {{{2
+" Vim script. {{{2
 
-  call easytags#define_tagkind({
-        \ 'filetype': 'vim',
-        \ 'hlgroup': 'vimAutoGroup',
-        \ 'filter': 'get(v:val, "kind") ==# "a"'})
+call easytags#define_tagkind({
+      \ 'filetype': 'vim',
+      \ 'hlgroup': 'vimAutoGroup',
+      \ 'filter': 'get(v:val, "kind") ==# "a"'})
 
-  highlight def link vimAutoGroup vimAutoEvent
+highlight def link vimAutoGroup vimAutoEvent
 
-  call easytags#define_tagkind({
-        \ 'filetype': 'vim',
-        \ 'hlgroup': 'vimCommand',
-        \ 'filter': 'get(v:val, "kind") ==# "c"',
-        \ 'pattern_prefix': '\(\(^\|\s\):\?\)\@<=',
-        \ 'pattern_suffix': '\(!\?\(\s\|$\)\)\@='})
+call easytags#define_tagkind({
+      \ 'filetype': 'vim',
+      \ 'hlgroup': 'vimCommand',
+      \ 'filter': 'get(v:val, "kind") ==# "c"',
+      \ 'pattern_prefix': '\(\(^\|\s\):\?\)\@<=',
+      \ 'pattern_suffix': '\(!\?\(\s\|$\)\)\@='})
 
-  " Exuberant Ctags doesn't mark script local functions in Vim scripts as
-  " "static". When your tags file contains search patterns this plug-in can use
-  " those search patterns to check which Vim script functions are defined
-  " globally and which script local.
+" Exuberant Ctags doesn't mark script local functions in Vim scripts as
+" "static". When your tags file contains search patterns this plug-in can use
+" those search patterns to check which Vim script functions are defined
+" globally and which script local.
 
-  call easytags#define_tagkind({
-        \ 'filetype': 'vim',
-        \ 'hlgroup': 'vimFuncName',
-        \ 'filter': 'get(v:val, "kind") ==# "f" && get(v:val, "cmd") !~? ''<sid>\w\|\<s:\w''',
-        \ 'pattern_prefix': '\C\%(\<s:\|<[sS][iI][dD]>\)\@<!\<'})
+call easytags#define_tagkind({
+      \ 'filetype': 'vim',
+      \ 'hlgroup': 'vimFuncName',
+      \ 'filter': 'get(v:val, "kind") ==# "f" && get(v:val, "cmd") !~? ''<sid>\w\|\<s:\w''',
+      \ 'pattern_prefix': '\C\%(\<s:\|<[sS][iI][dD]>\)\@<!\<'})
 
-  call easytags#define_tagkind({
-        \ 'filetype': 'vim',
-        \ 'hlgroup': 'vimScriptFuncName',
-        \ 'filter': 'get(v:val, "kind") ==# "f" && get(v:val, "cmd") =~? ''<sid>\w\|\<s:\w''',
-        \ 'pattern_prefix': '\C\%(\<s:\|<[sS][iI][dD]>\)'})
+call easytags#define_tagkind({
+      \ 'filetype': 'vim',
+      \ 'hlgroup': 'vimScriptFuncName',
+      \ 'filter': 'get(v:val, "kind") ==# "f" && get(v:val, "cmd") =~? ''<sid>\w\|\<s:\w''',
+      \ 'pattern_prefix': '\C\%(\<s:\|<[sS][iI][dD]>\)'})
 
-  highlight def link vimScriptFuncName vimFuncName
+highlight def link vimScriptFuncName vimFuncName
 
-  " Python. {{{2
+" Python. {{{2
 
-  call easytags#define_tagkind({
-        \ 'filetype': 'python',
-        \ 'hlgroup': 'pythonFunction',
-        \ 'filter': 'get(v:val, "kind") ==# "f"',
-        \ 'pattern_prefix': '\%(\<def\s\+\)\@<!\<'})
+call easytags#define_tagkind({
+      \ 'filetype': 'python',
+      \ 'hlgroup': 'pythonFunction',
+      \ 'filter': 'get(v:val, "kind") ==# "f"',
+      \ 'pattern_prefix': '\%(\<def\s\+\)\@<!\<'})
 
-  call easytags#define_tagkind({
-        \ 'filetype': 'python',
-        \ 'hlgroup': 'pythonMethod',
-        \ 'filter': 'get(v:val, "kind") ==# "m"',
-        \ 'pattern_prefix': '\.\@<='})
+call easytags#define_tagkind({
+      \ 'filetype': 'python',
+      \ 'hlgroup': 'pythonMethod',
+      \ 'filter': 'get(v:val, "kind") ==# "m"',
+      \ 'pattern_prefix': '\.\@<='})
 
-  highlight def link pythonMethodTag pythonFunction
+highlight def link pythonMethodTag pythonFunction
 
-  " Java. {{{2
+" Java. {{{2
 
-  call easytags#define_tagkind({
-        \ 'filetype': 'java',
-        \ 'hlgroup': 'javaClass',
-        \ 'filter': 'get(v:val, "kind") ==# "c"'})
+call easytags#define_tagkind({
+      \ 'filetype': 'java',
+      \ 'hlgroup': 'javaClass',
+      \ 'filter': 'get(v:val, "kind") ==# "c"'})
 
-  call easytags#define_tagkind({
-        \ 'filetype': 'java',
-        \ 'hlgroup': 'javaMethod',
-        \ 'filter': 'get(v:val, "kind") ==# "m"'})
+call easytags#define_tagkind({
+      \ 'filetype': 'java',
+      \ 'hlgroup': 'javaMethod',
+      \ 'filter': 'get(v:val, "kind") ==# "m"'})
 
-  highlight def link javaClass Identifier
-  highlight def link javaMethod Function
+highlight def link javaClass Identifier
+highlight def link javaMethod Function
 
-  " Restore "cpoptions".
-  let &cpo = s:cpo_save
-  unlet s:cpo_save
+" }}}
 
-endif
+" Restore "cpoptions".
+let &cpo = s:cpo_save
+unlet s:cpo_save
 
 " vim: ts=2 sw=2 et
diff --git a/easytags.vim b/easytags.vim
index af4ea01..fc6ab77 100644
--- a/easytags.vim
+++ b/easytags.vim
@@ -1,10 +1,10 @@
 " Vim plug-in
 " Maintainer: Peter Odding <peter@peterodding.com>
-" Last Change: June 11, 2010
+" Last Change: June 13, 2010
 " URL: http://peterodding.com/code/vim/easytags
 " Requires: Exuberant Ctags (http://ctags.sf.net)
 " License: MIT
-" Version: 1.8
+" Version: 1.9
 
 " Support for automatic update using the GLVS plug-in.
 " GetLatestVimScripts: 3114 1 :AutoInstall: easytags.zip