Version detection, better error handling, bug fix for dynamic highlighting

 * The plug-in now executes `ctags --version` on startup to verify that
   the correct version of Exuberant Ctags is installed because some
   systems (including Mac OS X apparently) ship with a `/usr/bin/ctags`
   installed that doesn't understand the extensive set of command-line
   arguments supported by Exuberant Ctags.

 * When a file was edited multiple times the dynamic highlighting
   wouldn't refresh because the plug-in thought the highlighting was
   still in effect while in reality it was cleared by reading the file
   again. Now the highlighting will be refreshed on the next CursorHold
   event like it's supposed to.

3 files changed, 78 insertions, 37 deletions

diff --git a/TODO.md b/TODO.md
index 6a6a717..798a258 100644
--- a/TODO.md
+++ b/TODO.md
@@ -31,3 +31,11 @@
    `~/.vim/autoload/easytags.vim` (a symbolic link to
    `~/Development/Vim/vim-easytags/autoload.vim`). I was already editing
    `~/.vim/autoload/easytags.vim` in another Vim buffer.
+
+ * Convert `easytags#update_cmd()` to a function that can be executed on a
+   list of files and will only execute Exuberant Ctags once to do so, then
+   change `:UpdateTags` to accept an optional file glob, e.g. `:UpdateTags
+   /usr/include/lua5.1/*.h` and call `easytags#update_cmd()` on the matching
+   files.
+
+vim: ai nofen
diff --git a/autoload.vim b/autoload.vim
index b536908..efd18ce 100644
--- a/autoload.vim
+++ b/autoload.vim
@@ -1,8 +1,10 @@
 " Vim script
 " Maintainer: Peter Odding <peter@peterodding.com>
-" Last Change: June 14, 2010
+" Last Change: June 15, 2010
 " URL: http://peterodding.com/code/vim/easytags
 
+let s:script = expand('<sfile>:p:~')
+
 " Public interface through (automatic) commands. {{{1
 
 function! easytags#autoload() " {{{2
@@ -28,7 +30,7 @@ function! easytags#autoload() " {{{2
       let b:easytags_last_highlighted = localtime()
     endif
   catch
-    call xolox#warning("easytags.vim: %s (at %s)", v:exception, v:throwpoint)
+    call xolox#warning("%s: %s (at %s)", s:script, v:exception, v:throwpoint)
   endtry
 endfunction
 
@@ -59,7 +61,8 @@ function! easytags#update_cmd(filter_invalid_tags) " {{{2
           call filter(entries, join(filters, ' && '))
           if len(entries) != num_entries
             if !easytags#write_tagsfile(tagsfile, header, entries)
-              throw "Failed to write filtered tags file!"
+              let msg = "Failed to write filtered tags file %s!"
+              throw printf(msg, fnamemodify(tagsfile, ':~'))
             endif
           endif
         endif
@@ -69,16 +72,18 @@ function! easytags#update_cmd(filter_invalid_tags) " {{{2
         call add(command, shellescape(filename))
         let listing = system(join(command))
         if v:shell_error
-          throw "Failed to update tags file! (Ctags output: `" . listing . "')"
+          let msg = "Failed to update tags file %s: %s!"
+          throw printf(msg, fnamemodify(tagsfile, ':~'), strtrans(v:exception))
         endif
         call easytags#add_tagged_file(filename)
       endif
-      call xolox#timer#stop(start, "easytags.vim: Updated tags in %s second(s)")
+      let msg = "%s: Updated tags for %s in %s."
+      call xolox#timer#stop(msg, s:script, expand('%:p:~'), start)
       return 1
     endif
     return 0
   catch
-    call xolox#warning("easytags.vim: %s (at %s)", v:exception, v:throwpoint)
+    call xolox#warning("%s: %s (at %s)", s:script, v:exception, v:throwpoint)
   endtry
 endfunction
 
@@ -108,10 +113,11 @@ function! easytags#highlight_cmd() " {{{2
         endif
       endfor
       redraw
-      call xolox#timer#stop(start, "easytags.vim: Highlighted tags in %s second(s)")
+      let msg = "%s: Highlighted tags in %s in %s."
+      call xolox#timer#stop(msg, s:script, expand('%:p:~'), start)
     endif
   catch
-    call xolox#warning("easytags.vim: %s (at %s)", v:exception, v:throwpoint)
+    call xolox#warning("%s: %s (at %s)", s:script, v:exception, v:throwpoint)
   endtry
 endfunction
 
@@ -122,11 +128,13 @@ function! easytags#supported_filetypes() " {{{2
     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!"
+      let msg = "Failed to get supported languages! (output: %s)"
+      throw printf(msg, strtrans(listing))
     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)")
+    let msg = "%s: Retrieved supported languages in %s."
+    call xolox#timer#stop(msg, s:script, start)
   endif
   return s:supported_filetypes
 endfunction
@@ -173,8 +181,8 @@ 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)"
-    throw printf(message, tagsfile)
+    let message = "The tags file %s isn't writable!"
+    throw printf(message, fnamemodify(tagsfile, ':~'))
   endif
   return tagsfile
 endfunction
diff --git a/easytags.vim b/easytags.vim
index fc6ab77..30efb3d 100644
--- a/easytags.vim
+++ b/easytags.vim
@@ -1,10 +1,10 @@
 " Vim plug-in
 " Maintainer: Peter Odding <peter@peterodding.com>
-" Last Change: June 13, 2010
+" Last Change: June 15, 2010
 " URL: http://peterodding.com/code/vim/easytags
 " Requires: Exuberant Ctags (http://ctags.sf.net)
 " License: MIT
-" Version: 1.9
+" Version: 1.9.3
 
 " Support for automatic update using the GLVS plug-in.
 " GetLatestVimScripts: 3114 1 :AutoInstall: easytags.zip
@@ -40,38 +40,62 @@ if !exists('g:easytags_ignored_filetypes')
   let g:easytags_ignored_filetypes = '^tex$'
 endif
 
-" Before sourcing the rest of the plug-in first check that the location of the
-" "Exuberant Ctags" program has been configured or that the program exists in
-" one of its default locations.
-
-if exists('g:easytags_cmd') && executable(g:easytags_cmd)
-  let s:ctags_installed = 1
-else
+function! s:InitEasyTags(version)
+  " Check that the location of Exuberant Ctags has been configured or that the
+  " correct version of the program exists in one of its default locations.
+  if exists('g:easytags_cmd') && s:CheckCtags(g:easytags_cmd, a:version)
+    return 1
+  endif
   " On Ubuntu Linux, Exuberant Ctags is installed as `ctags'. On Debian Linux,
   " Exuberant Ctags is installed as `exuberant-ctags'. On Free-BSD, Exuberant
   " Ctags is installed as `exctags'. Finally there is `ctags.exe' on Windows.
-  for s:command in ['ctags', 'exuberant-ctags', 'esctags', 'ctags.exe']
-    if executable(s:command)
-      let g:easytags_cmd = s:command
-      let s:ctags_installed = 1
-      break
+  for name in ['ctags', 'exuberant-ctags', 'esctags']
+    if s:CheckCtags(name, a:version)
+      let g:easytags_cmd = name
+      return 1
     endif
   endfor
-  unlet s:command
-endif
-
-if !exists('s:ctags_installed')
-  echomsg "easytags.vim: Exuberant Ctags unavailable! Plug-in not loaded."
-  if executable('apt-get')
-    echomsg "On Ubuntu & Debian Linux, you can install Exuberant Ctags"
-    echomsg "by installing the package named `exuberant-ctags':"
-    echomsg "  sudo apt-get install exuberant-ctags"
+endfunction
+
+function! s:CheckCtags(name, version)
+  " Not every executable out there named `ctags' is in fact Exuberant Ctags.
+  " This function makes sure it is because the easytags plug-in requires the
+  " --list-languages option.
+  if executable(a:name)
+    let listing = system(a:name . ' --version')
+    let pattern = 'Exuberant Ctags \zs\d\+\(\.\d\+\)*'
+    let g:easytags_ctags_version = matchstr(listing, pattern)
+    return s:VersionToNumber(g:easytags_ctags_version) >= a:version
+  endif
+endfunction
+
+function! s:VersionToNumber(s)
+  let values = split(a:s, '\.')
+  if len(values) == 1
+    return values[0] * 10
+  elseif len(values) >= 2
+    return values[0] * 10 + values[1][0]
+  endif
+endfunction
+
+if !s:InitEasyTags(55)
+  if !exists('g:easytags_ctags_version') || empty(g:easytags_ctags_version)
+    let msg = "easytags.vim: Plug-in not loaded because Exuberant Ctags isn't installed!"
+    if executable('apt-get')
+      let msg ,= " On Ubuntu & Debian you can install Exuberant Ctags by"
+      let msg .= " installing the package named `exuberant-ctags':"
+      let msg .= " sudo apt-get install exuberant-ctags"
+    else
+      let msg .= " Please download & install Exuberant Ctags from http://ctags.sf.net"
+    endif
+    echomsg msg
   else
-    echomsg "Please download & install Exuberant Ctags from http://ctags.sf.net"
+    let msg = "easytags.vim: Plug-in not loaded because Exuberant Ctags 5.5"
+    let msg .= " or newer is required while you have version %s installed!"
+    echomsg printf(msg, g:easytags_ctags_version)
   endif
   finish
 endif
-unlet s:ctags_installed
 
 " Let Vim know about the global tags file created by this plug-in.
 
@@ -106,6 +130,7 @@ augroup PluginEasyTags
   endif
   if g:easytags_on_cursorhold
     autocmd CursorHold,CursorHoldI * call easytags#autoload()
+    autocmd BufReadPost * unlet! b:easytags_last_highlighted
   endif
   autocmd User PublishPre HighlightTags
 augroup END