Async support

README.md

@@ -122,7 +122,8 @@ Present maintainer, yours truly, [kind of wishes they never forked][sadface],
 contributes to both, and wouldn't mind seeing them merged again. ag.vim got a
 nice code clean-up (which ack.vim is now hopefully getting), and ack.vim picked
 up a few features that haven't made their way to ag.vim, like `:AckWindow`,
-optional background search execution with [vim-dispatch], and auto-previewing.
+optional background search execution with [vim-dispatch] or [async.vim], and
+auto-previewing.
 
 #### I don't want to jump to the first result automatically. ####
 
@@ -160,4 +161,5 @@ And of course, where would we be without [ack]. And, you know, Vim.
 [ack]: http://beyondgrep.com/
 
 [vim-dispatch]: https://github.com/tpope/vim-dispatch
+[async.vim]: https://github.com/prabirshrestha/async.vim
 [releases]: https://github.com/mileszs/ack.vim/releases

autoload/ack.vim

@@ -2,14 +2,6 @@ if exists('g:autoloaded_ack') || &cp
   finish
 endif
 
-if exists('g:ack_use_dispatch')
-  if g:ack_use_dispatch && !exists(':Dispatch')
-    call s:Warn('Dispatch not loaded! Falling back to g:ack_use_dispatch = 0.')
-    let g:ack_use_dispatch = 0
-  endif
-else
-  let g:ack_use_dispatch = 0
-endif
 
 "-----------------------------------------------------------------------------
 " Public API
@@ -51,18 +43,23 @@ function! ack#Ack(cmd, args) "{{{
   "       allow for passing arguments etc
   let l:escaped_args = escape(l:grepargs, '|#%')
 
+  let ShowResults = function('s:ShowResults', [l:grepargs])
+
   echo "Searching ..."
 
   if g:ack_use_dispatch
     call s:SearchWithDispatch(l:grepprg, l:escaped_args, l:grepformat)
+  elseif g:ack_use_async
+    call s:SearchWithAsync(l:grepprg, l:escaped_args, l:grepformat, ShowResults)
   else
     call s:SearchWithGrep(a:cmd, l:grepprg, l:escaped_args, l:grepformat)
   endif
 
-  " Dispatch has no callback mechanism currently, we just have to display the
-  " list window early and wait for it to populate :-/
-  call ack#ShowResults()
-  call s:Highlight(l:grepargs)
+  if !g:ack_use_async
+    " Dispatch has no callback mechanism currently, we just have to display the
+    " list window early and wait for it to populate :-/
+    call ShowResults()
+  endif
 endfunction "}}}
 
 function! ack#AckFromSearch(cmd, args) "{{{
@@ -149,6 +146,11 @@ function! s:GetDocLocations() "{{{
   return dp
 endfunction "}}}
 
+function! s:ShowResults(grepargs) "{{{
+  call ack#ShowResults()
+  call s:Highlight(a:grepargs)
+endfunction "}}}
+
 function! s:Highlight(args) "{{{
   if !g:ackhighlight
     return
@@ -160,8 +162,27 @@ endfunction "}}}
 
 " Initialize state for an :Ack* or :LAck* search
 function! s:Init(cmd) "{{{
-  let s:searching_filepaths = (a:cmd =~# '-g$') ? 1 : 0
-  let s:using_loclist       = (a:cmd =~# '^l') ? 1 : 0
+  let s:searching_filepaths       = (a:cmd =~# '-g$') ? 1 : 0
+  let s:using_loclist             = (a:cmd =~# '^l') ? 1 : 0
+  let s:using_existing_qfloc_list = (a:cmd =~# '^l\?grepadd') ? 1 : 0
+
+  if exists('g:ack_use_dispatch')
+    if g:ack_use_dispatch && !exists(':Dispatch')
+      call s:Warn('Dispatch not loaded! Falling back to g:ack_use_dispatch = 0.')
+      let g:ack_use_dispatch = 0
+    endif
+  else
+    let g:ack_use_dispatch = 0
+  endif
+
+  if exists('g:ack_use_async')
+    if g:ack_use_async && !(&rtp =~ 'async.vim')
+      call s:Warn('async not loaded! Falling back to g:ack_use_async = 0.')
+      let g:ack_use_async = 0
+    endif
+  else
+    let g:ack_use_async = 0
+  endif
 
   if g:ack_use_dispatch && s:using_loclist
     call s:Warn('Dispatch does not support location lists! Proceeding with quickfix...')
@@ -204,6 +225,70 @@ function! s:SearchWithDispatch(grepprg, grepargs, grepformat) "{{{
   endtry
 endfunction "}}}
 
+function! s:SearchWithAsync(grepprg, grepargs, grepformat, success_cb) "{{{
+  " We don't execute a :grep command for Dispatch, so add -g here instead
+  if s:SearchingFilepaths()
+    let l:grepprg = a:grepprg . ' -g'
+  else
+    let l:grepprg = a:grepprg
+  endif
+
+  let cmd = l:grepprg . ' ' . a:grepargs
+  let job_cmd = split(&shell) + split(&shellcmdflag) + [cmd]
+  let ctx = {
+              \ 'data': [],
+              \ 'grepformat': a:grepformat,
+              \ 'title': ':' . cmd,
+              \ 'success_cb': a:success_cb,
+              \}
+
+  function! ctx.append(job_id, data, event_type) "{{{
+    let self.ctx.data = self.ctx.data + a:data
+  endfunction "}}}
+
+  function! ctx.complete(job_id, data, event_type) " {{{
+    " Later on we are using {c,l}addexpr and {c,l}getexpr to populate
+    " the quickfix/location-list, and these use the global errorformat so
+    " that's what needs to be temporarily changed.
+    " https://github.com/vim/vim/issues/569
+    let l:errorformat_bak = &errorformat
+
+    try
+      let &errorformat = self.ctx.grepformat
+      let entries = filter(self.ctx.data, 'len(v:val)')
+
+      if s:UsingLocList()
+          if s:UsingExistingQFLocList()
+              laddexpr entries
+          else
+              lgetexpr entries
+          endif
+          call setloclist(0, [], 'a', { 'title': self.ctx.title })
+      else
+          if s:UsingExistingQFLocList()
+            caddexpr entries
+          else
+            cgetexpr entries
+          endif
+          call setqflist([], 'a', { 'title': self.ctx.title })
+      endif
+    finally
+      let &errorformat = errorformat_bak
+    endtry
+    call self.ctx.success_cb()
+  endfunction "}}}
+
+  let jobid = async#job#start(job_cmd, {
+      \ 'on_stdout': ctx.append,
+      \ 'on_exit': ctx.complete,
+      \ 'ctx': ctx,
+  \ })
+
+  if jobid <= 0
+    call s:Error('Failed to run the following command: ' . string(job_cmd))
+  endif
+endfunction "}}}
+
 function! s:SearchWithGrep(grepcmd, grepprg, grepargs, grepformat) "{{{
   let l:grepprg_bak    = &l:grepprg
   let l:grepformat_bak = &grepformat
@@ -238,9 +323,18 @@ function! s:UsingLocList() "{{{
   return get(s:, 'using_loclist', 0)
 endfunction "}}}
 
+" Were we invoked with a :AckAdd or :LackAdd command?
+function! s:UsingExistingQFLocList() " {{{
+  return get(s:, 'using_existing_qfloc_list', 0)
+endfunction "}}}
+
 function! s:Warn(msg) "{{{
   echohl WarningMsg | echomsg 'Ack: ' . a:msg | echohl None
 endf "}}}
 
+function! s:Error(msg) "{{{
+  echohl ErrorMsg | echomsg 'Ack: ' . a:msg | echohl None
+endf "}}}
+
 let g:autoloaded_ack = 1
 " vim:set et sw=2 ts=2 tw=78 fdm=marker

doc/ack.txt

@@ -219,6 +219,17 @@ acceptable tradeoffs for very large projects where searches are slow.
 Example:
 >
         let g:ack_use_dispatch = 1
+<
+                                                          *g:ack_use_async*
+g:ack_use_async
+Default: 0
+
+Use this option to use async.vim to run searches in the background, leveraging
+async job support added to VIM 8.
+
+Example:
+>
+        let g:ack_use_async = 1
 <
                                              *g:ack_use_cword_for_empty_search*
 g:ack_use_cword_for_empty_search