Workaround low 'updatetime' intelligently

This should hopefully resolve the following issues and pull
requests: #31, #33, #42. I tried several of their suggestions
in Vim 7.2 & 7.3 but it didn't work as it should IMHO.

All of the issues and pull requests seem to imply that CursorHold
events fire continuously when you set a low enough updatetime, but
in my testing on Vim 7.2 and 7.3 this is not true. The event fires
once, then Vim waits for user input before any new events fire.
I'm not sure exactly what user input is required; moving the
text cursor is not always enough but mode switching is.

So what happens (in my testing) with all of the proposed solutions is
that you stop typing for 'updatetime' milliseconds, the event fires, the
plug-in simply increments or decrements a counter and then Vim just sits
there doing absolutely nothing expect blinking the cursor...

What I'm now trying instead is to remember the last time the plug-in was
executed (the result of localtime()) and not acting on the CursorHold
event until the following condition holds true:

  localtime() > (last_automatic_run + (easytags_updatetime_min/1000))

I hope this provides a reliable solution. In any case it should be
better than the previous annoying behavior :-)

3 files changed, 50 insertions, 52 deletions

diff --git a/README.md b/README.md
index 2e5b1bd..332a788 100644
--- a/README.md
+++ b/README.md
@@ -125,11 +125,9 @@ Note: Like the `g:easytags_always_enabled` option, if you change this option it
 
 ### The `g:easytags_updatetime_min` option
 
-Vim has a setting which influences how often the plug-in is automatically executed. When this setting is too low, the plug-in can break. For this reason the plug-in warns you when ['updatetime'][updatetime] is lower than 4000 milliseconds. If you really want the plug-in to be executed more than once every 4 seconds (without a warning) you can lower the minimum acceptable updatetime by setting this option (number of milliseconds).
+Vim has a setting which influences how often the plug-in is automatically executed. When this setting is too low, the plug-in can break. For this reason the plug-in compensates by keeping track of when it was last executed. You'll get one warning when the plug-in first notices the low value, after that it will shut up. The default value of this option is 4000 milliseconds (4 seconds).
 
-### The `g:easytags_updatetime_autodisable` option
-
-Other plug-ins may lower the ['updatetime'][updatetime] value in certain contexts, e.g. insert mode in the case of the [neocomplcache][neocomplcache] plug-in. By setting this option to 1 (true) you can configure the easytags plug-in so that it doesn't give warnings about the updatetime option but instead skip updating and highlighting while the updatetime is set too low. When the updatetime is restored to a reasonable value the plug-in resumes.
+If you really want the plug-in to be executed more than once every 4 seconds you can lower the minimum acceptable updatetime by setting this option (as the number of milliseconds) however note that subsecond granularity is not supported.
 
 ### The `g:easytags_auto_update` option
 
diff --git a/autoload/xolox/easytags.vim b/autoload/xolox/easytags.vim
index 2197be6..0380956 100644
--- a/autoload/xolox/easytags.vim
+++ b/autoload/xolox/easytags.vim
@@ -3,7 +3,7 @@
 " Last Change: April 19, 2013
 " URL: http://peterodding.com/code/vim/easytags/
 
-let g:xolox#easytags#version = '3.0'
+let g:xolox#easytags#version = '3.1'
 
 " Public interface through (automatic) commands. {{{1
 
@@ -33,25 +33,32 @@ function! xolox#easytags#register(global) " {{{2
     endif
   endif
 endfunction
+ 
+" The localtime() when the CursorHold event last fired.
+let s:last_automatic_run = 0
 
 function! xolox#easytags#autoload(event) " {{{2
   try
     if a:event =~? 'cursorhold'
       " Only for the CursorHold automatic command: check for unreasonable
       " &updatetime values. The minimum value 4000 is kind of arbitrary
-      " (apart from being Vim's default) so I made it configurable:
+      " (apart from being Vim's default) so I made it configurable.
       let updatetime_min = xolox#misc#option#get('easytags_updatetime_min', 4000)
       if &updatetime < updatetime_min
-        " Other plug-ins may lower &updatetime in certain contexts, e.g.
-        " insert mode in the case of the neocomplcache plug-in. The following
-        " option (disabled by default unless neocomplcache is loaded) silences
-        " the warning and makes the easytags plug-in skip the update and
-        " highlight. When the &updatetime is restored to a reasonable value
-        " the plug-in resumes.
-        if xolox#misc#option#get('easytags_updatetime_autodisable', exists('g:loaded_neocomplcache'))
-          return
+        if s:last_automatic_run == 0
+          " Warn once about the low &updatetime value.
+          call xolox#misc#msg#warn("easytags.vim %s: The 'updatetime' option has an unreasonably low value, so I'll start compensating (see the easytags_updatetime_min option).", g:xolox#easytags#version)
+          let s:last_automatic_run = localtime()
         else
-          call xolox#misc#msg#warn("easytags.vim %s: I'm being executed every %i milliseconds! Please :set updatetime=%i. To find where 'updatetime' was changed execute ':verb set ut?'", g:xolox#easytags#version, &updatetime, updatetime_min)
+          let next_scheduled_run = s:last_automatic_run + max([1, updatetime_min / 1000])
+          if localtime() < next_scheduled_run
+            " It's not our time yet; wait for the next event.
+            call xolox#misc#msg#debug("easytags.vim %s: Skipping this beat of 'updatetime' to compensate for low value.", g:xolox#easytags#version)
+            return
+          else
+            call xolox#misc#msg#debug("easytags.vim %s: This is our beat of 'updatetime'!", g:xolox#easytags#version)
+            let s:last_automatic_run = localtime()
+          endif
         endif
       endif
     endif
diff --git a/doc/easytags.txt b/doc/easytags.txt
index c594817..b2b5fdf 100644
--- a/doc/easytags.txt
+++ b/doc/easytags.txt
@@ -19,14 +19,13 @@ Contents ~
   6. The |g:easytags_always_enabled| option
   7. The |g:easytags_on_cursorhold| option
   8. The |g:easytags_updatetime_min| option
-  9. The |g:easytags_updatetime_autodisable| option
-  10. The |g:easytags_auto_update| option
-  11. The |g:easytags_auto_highlight| option
-  12. The |g:easytags_autorecurse| option
-  13. The |g:easytags_include_members| option
-  14. The |g:easytags_resolve_links| option
-  15. The |g:easytags_suppress_ctags_warning| option
-  16. The |g:easytags_ignored_syntax_groups| option
+  9. The |g:easytags_auto_update| option
+  10. The |g:easytags_auto_highlight| option
+  11. The |g:easytags_autorecurse| option
+  12. The |g:easytags_include_members| option
+  13. The |g:easytags_resolve_links| option
+  14. The |g:easytags_suppress_ctags_warning| option
+  15. The |g:easytags_ignored_syntax_groups| option
  5. Faster syntax highlighting using Python |easytags-faster-syntax-highlighting-using-python|
   1. The |g:easytags_python_enabled| option
   2. The |g:easytags_python_script| option
@@ -293,20 +292,15 @@ The *g:easytags_updatetime_min* option
 
 Vim has a setting which influences how often the plug-in is automatically
 executed. When this setting is too low, the plug-in can break. For this reason
-the plug-in warns you when |'updatetime'| is lower than 4000 milliseconds. If
-you really want the plug-in to be executed more than once every 4 seconds
-(without a warning) you can lower the minimum acceptable updatetime by setting
-this option (number of milliseconds).
+the plug-in compensates by keeping track of when it was last executed. You'll
+get one warning when the plug-in first notices the low value, after that it
+will shut up. The default value of this option is 4000 milliseconds (4
+seconds).
 
--------------------------------------------------------------------------------
-The *g:easytags_updatetime_autodisable* option
-
-Other plug-ins may lower the |'updatetime'| value in certain contexts, e.g.
-insert mode in the case of the neocomplcache [10] plug-in. By setting this
-option to 1 (true) you can configure the easytags plug-in so that it doesn't
-give warnings about the updatetime option but instead skip updating and
-highlighting while the updatetime is set too low. When the updatetime is
-restored to a reasonable value the plug-in resumes.
+If you really want the plug-in to be executed more than once every 4 seconds
+you can lower the minimum acceptable updatetime by setting this option (as the
+number of milliseconds) however note that subsecond granularity is not
+supported.
 
 -------------------------------------------------------------------------------
 The *g:easytags_auto_update* option
@@ -374,14 +368,14 @@ your vimrc script, a file type plug-in, etc.):
 -------------------------------------------------------------------------------
 The *g:easytags_resolve_links* option
 
-UNIX has symbolic links [11] and hard links [12], both of which conflict with
+UNIX has symbolic links [10] and hard links [11], both of which conflict with
 the concept of having one unique location for every identifier. With regards
 to hard links there's not much anyone can do, but because I use symbolic links
 quite a lot I've added this option. It's disabled by default since it has a
 small performance impact and might not do what unknowing users expect it to:
 When you enable this option the plug-in will resolve symbolic links in
 pathnames, which means your tags file will only contain entries with canonical
-pathnames [13]. To enable this option (which I strongly suggest doing when you
+pathnames [12]. To enable this option (which I strongly suggest doing when you
 run UNIX and use symbolic links) execute the following Vim command:
 >
     :let g:easytags_resolve_links = 1
@@ -465,11 +459,11 @@ modes (except of course for the 'Tag' suffix).
 Passing custom command line arguments to Exuberant Ctags ~
 
 You may want to run Exuberant Ctags with specific command line options, for
-example the code_complete [14] plug-in requires the signature field to be
+example the code_complete [13] plug-in requires the signature field to be
 present. To do this you can create a configuration file for Exuberant Ctags,
 e.g. '~/.ctags' on UNIX or '%USERPROFILE%\ctags.cnf' on Windows. The file
 should contain one command line option per line. See the Exuberant Ctags
-manual [15] for details.
+manual [14] for details.
 
 ===============================================================================
                                                       *easytags-troubleshooting*
@@ -569,7 +563,7 @@ project directories.
 -------------------------------------------------------------------------------
 The plug-in doesn't seem to work in Cygwin ~
 
-If you want to use the plug-in with Vim under Cygwin [16], you need to have
+If you want to use the plug-in with Vim under Cygwin [15], you need to have
 the Cygwin version of Ctags installed instead of the Windows version (thanks
 to Alex Zuroff for reporting this!).
 
@@ -580,13 +574,13 @@ Contact ~
 If you have questions, bug reports, suggestions, etc. the author can be
 contacted at peter@peterodding.com. The latest version is available at
 http://peterodding.com/code/vim/easytags/ and http://github.com/xolox/vim-easytags.
-If you like this plug-in please vote for it on Vim Online [17].
+If you like this plug-in please vote for it on Vim Online [16].
 
 ===============================================================================
                                                               *easytags-license*
 License ~
 
-This software is licensed under the MIT license [18]. Copyright 2011 Peter
+This software is licensed under the MIT license [17]. Copyright 2011 Peter
 Odding <peter@peterodding.com>.
 
 ===============================================================================
@@ -602,14 +596,13 @@ References ~
 [7] http://peterodding.com/code/vim/shell/
 [8] http://en.wikipedia.org/wiki/Dynamic-link_library
 [9] https://npmjs.org/package/jsctags
-[10] http://www.vim.org/scripts/script.php?script_id=2620
-[11] http://en.wikipedia.org/wiki/Symbolic_link
-[12] http://en.wikipedia.org/wiki/Hard_link
-[13] http://en.wikipedia.org/wiki/Canonicalization
-[14] http://www.vim.org/scripts/script.php?script_id=1764
-[15] http://ctags.sourceforge.net/ctags.html#FILES
-[16] http://en.wikipedia.org/wiki/Cygwin
-[17] http://www.vim.org/scripts/script.php?script_id=3114
-[18] http://en.wikipedia.org/wiki/MIT_License
+[10] http://en.wikipedia.org/wiki/Symbolic_link
+[11] http://en.wikipedia.org/wiki/Hard_link
+[12] http://en.wikipedia.org/wiki/Canonicalization
+[13] http://www.vim.org/scripts/script.php?script_id=1764
+[14] http://ctags.sourceforge.net/ctags.html#FILES
+[15] http://en.wikipedia.org/wiki/Cygwin
+[16] http://www.vim.org/scripts/script.php?script_id=3114
+[17] http://en.wikipedia.org/wiki/MIT_License
 
 vim: ft=help