Neovim: run diffs asynchronously.

README.mkd

@@ -5,6 +5,7 @@ A Vim plugin which shows a git diff in the 'gutter' (sign column).  It shows whe
 Features:
 
 * Shows signs for added, modified, and removed lines.
+* Neovim: runs the diffs asynchronously.
 * Ensures signs are always as up to date as possible (but without running more than necessary).
 * Quick jumping between blocks of changed lines ("hunks").
 * Stage/revert/preview individual hunks.

autoload/gitgutter.vim

@@ -20,7 +20,43 @@ function! gitgutter#process_buffer(bufnr, realtime)
     try
       if !a:realtime || gitgutter#utility#has_fresh_changes()
         let diff = gitgutter#diff#run_diff(a:realtime || gitgutter#utility#has_unsaved_changes(), 1)
-        call gitgutter#hunk#set_hunks(gitgutter#diff#parse_diff(diff))
+        if diff != 'async'
+          call gitgutter#handle_diff(diff)
+        endif
+      endif
+    catch /diff failed/
+      call gitgutter#hunk#reset()
+    endtry
+  else
+    call gitgutter#hunk#reset()
+  endif
+endfunction
+
+
+function! gitgutter#handle_diff_job(job_id, data, event)
+  if a:event == 'stdout'
+    " a:data is a list
+    call gitgutter#utility#job_output_received(a:job_id, 'stdout')
+    call gitgutter#handle_diff(join(a:data,"\n")."\n")
+
+  elseif a:event == 'exit'
+    " If the exit event is triggered without a preceding stdout event,
+    " the diff was empty.
+    if gitgutter#utility#is_pending_job(a:job_id)
+      call gitgutter#handle_diff("")
+      call gitgutter#utility#job_output_received(a:job_id, 'exit')
+    endif
+
+  else
+    call gitgutter#hunk#reset()
+    call gitgutter#utility#job_output_received(a:job_id, 'stderr')
+
+  endif
+endfunction
+
+
+function! gitgutter#handle_diff(diff)
+  call gitgutter#hunk#set_hunks(gitgutter#diff#parse_diff(a:diff))
   let modified_lines = gitgutter#diff#process_hunks(gitgutter#hunk#hunks())
 
   if len(modified_lines) > g:gitgutter_max_signs
@@ -34,13 +70,6 @@ function! gitgutter#process_buffer(bufnr, realtime)
   endif
 
   call gitgutter#utility#save_last_seen_change()
-      endif
-    catch /diff failed/
-      call gitgutter#hunk#reset()
-    endtry
-  else
-    call gitgutter#hunk#reset()
-  endif
 endfunction
 
 function! gitgutter#disable()

autoload/gitgutter/diff.vim

@@ -116,23 +116,35 @@ function! gitgutter#diff#run_diff(realtime, use_external_grep)
     endif
   end
 
-  let diff = gitgutter#utility#system(gitgutter#utility#command_in_directory_of_file(cmd))
-
-  if a:realtime
-    call delete(blob_file)
-    call delete(buff_file)
-  endif
-
-  if gitgutter#utility#shell_error()
-    " A shell error indicates the file is not tracked by git (unless something bizarre is going on).
-    throw 'diff failed'
-  endif
-
   if !tracked
     call setbufvar(bufnr, 'gitgutter_tracked', 1)
   endif
 
+  if has('nvim') && a:use_external_grep
+    let cmd = gitgutter#utility#command_in_directory_of_file(cmd)
+    " Note that when `cmd` doesn't produce any output, i.e. the diff is empty,
+    " the `stdout` event is not fired on the job handler.  Therefore we keep
+    " track of the jobs ourselves so we can spot empty diffs.
+    let job_id = jobstart([&shell, '-c', cmd], {
+          \ 'on_stdout': function('gitgutter#handle_diff_job'),
+          \ 'on_stderr': function('gitgutter#handle_diff_job'),
+          \ 'on_exit':   function('gitgutter#handle_diff_job')
+          \ })
+    call gitgutter#utility#pending_job(job_id)
+    return 'async'
+  else
+    let diff = gitgutter#utility#system(gitgutter#utility#command_in_directory_of_file(cmd))
+    if gitgutter#utility#shell_error()
+      " A shell error indicates the file is not tracked by git (unless something bizarre is going on).
+      throw 'diff failed'
+    endif
     return diff
+  endif
+
+  if a:realtime
+    " call delete(blob_file)
+    " call delete(buff_file)
+  endif
 endfunction
 
 function! gitgutter#diff#parse_diff(diff)

autoload/gitgutter/utility.vim

@@ -2,6 +2,7 @@ let s:file = ''
 let s:using_xolox_shell = -1
 let s:exit_code = 0
 let s:fish = &shell =~# 'fish'
+let s:jobs = {}
 
 function! gitgutter#utility#warn(message)
   echohl WarningMsg
@@ -162,3 +163,17 @@ endfunction
 function! gitgutter#utility#strip_trailing_new_line(line)
   return substitute(a:line, '\n$', '', '')
 endfunction
+
+function! gitgutter#utility#pending_job(job_id)
+  let s:jobs[a:job_id] = 1
+endfunction
+
+function! gitgutter#utility#is_pending_job(job_id)
+  return has_key(s:jobs, a:job_id)
+endfunction
+
+function! gitgutter#utility#job_output_received(job_id, event)
+  if has_key(s:jobs, a:job_id)
+    unlet s:jobs[a:job_id]
+  endif
+endfunction