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 :-)

1 files changed, 18 insertions, 11 deletions

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