--- a/autoload/gutentags/gtags_cscope.vim	Wed Jan 11 15:38:43 2017 -0800
+++ b/autoload/gutentags/gtags_cscope.vim	Wed Jan 11 23:50:00 2017 -0800
@@ -31,7 +31,23 @@
 
 " Gutentags Module Interface {{{
 
-let s:db_connected = 0
+let s:added_db_files = {}
+let s:job_db_files = []
+
+function! s:add_db(db_file) abort
+	if filereadable(a:db_file)
+		call gutentags#trace(
+					\"Adding cscope DB file: " . a:db_file)
+		set nocscopeverbose
+		execute 'cs add ' . fnameescape(a:db_file)
+		set cscopeverbose
+		let s:added_db_files[a:db_file] = 1
+	else
+		call gutentags#trace(
+					\"Not adding cscope DB file because it doesn't " .
+					\"exist yet: " . a:db_file)
+	endif
+endfunction
 
 function! gutentags#gtags_cscope#init(project_root) abort
 	let l:db_path = gutentags#get_cachefile(
@@ -44,7 +60,7 @@
 
 	let b:gutentags_files['gtags_cscope'] = l:db_file
 
-	execute 'set cscopeprg=' . g:gutentags_gtags_cscope_executable
+	execute 'set cscopeprg=' . fnameescape(g:gutentags_gtags_cscope_executable)
 
 	" The combination of gtags-cscope, vim's cscope and global files is
 	" a bit flaky. Environment variables are safer than vim passing
@@ -52,69 +68,127 @@
 	let $GTAGSDBPATH = l:db_path
 	let $GTAGSROOT = a:project_root
 
-	if g:gutentags_auto_add_gtags_cscope && filereadable(l:db_file)
-		set nocscopeverbose
-		execute 'cs add ' . fnameescape(l:db_file)
-		set cscopeverbose
-		let s:db_connected = 1
+	if g:gutentags_auto_add_gtags_cscope && !has_key(s:added_db_files, l:db_file)
+		let s:added_db_files[l:db_file] = 0
+		call s:add_db(l:db_file)
 	endif
 endfunction
 
-function! gutentags#gtags_cscope#command_terminated(job_id, data, event) abort
-	if a:data == 0
-		if !s:db_connected
-			set nocscopeverbose
-			execute 'cs add ' . fnameescape(self.db_file)
-			set cscopeverbose
-			let s:db_connected = 1
+function! gutentags#gtags_cscope#on_job_out(job, data) abort
+	call gutentags#trace(a:data)
+endfunction
+
+function! gutentags#gtags_cscope#on_job_exit(job, exit_val) abort
+	if a:exit_val != 0
+		echom "gutentags: gtags-cscope job failed :("
+		return
+	endif
+	if g:gutentags_auto_add_gtags_cscope
+		let l:idx = 0
+		let l:db_file = ''
+		for item in s:job_db_files
+			if item[0] == a:job
+				let l:db_file = item[1]
+				break
+			endif
+			let l:idx += 1
+		endfor
+		if l:db_file != ''
+			call s:add_db(l:db_file)
+			call remove(s:job_db_files, l:idx)
 		endif
 	endif
 endfunction
 
+function! s:get_unix_cmd(for_job, proj_options, db_path) abort
+	" Vim's `job_start` gets confused with quoted arguments on Unix,
+	" prefers lists.
+	if a:for_job
+		let l:cmd = [g:gutentags_gtags_executable] + a:proj_options
+		let l:cmd += ['--incremental', a:db_path]
+		return l:cmd
+	else
+		let l:cmd = gutentags#get_execute_cmd()
+		let l:cmd .= '"' . g:gutentags_gtags_executable . '"'
+		let l:cmd .= ' ' . join(a:proj_options, ' ')
+		let l:cmd .= ' --incremental '
+		let l:cmd .= ' "' . a:db_path . '" '
+		let l:cmd .= gutentags#get_execute_cmd_suffix()
+		return l:cmd
+	endif
+endfunction
+
+function! s:get_win32_cmd(for_job, proj_options, db_path) abort
+	" Win32 prefers strings either way.
+	let l:cmd = ''
+	if !a:for_job
+		let l:cmd = gutentags#get_execute_cmd()
+	endif
+	let l:cmd .= '"' . g:gutentags_gtags_executable . '"'
+	let l:cmd .= ' ' . join(a:proj_options, ' ')
+	let l:cmd .= ' --incremental '
+	let l:cmd .= ' "' . a:db_path . '"'
+	if !a:for_job
+		let l:cmd .= ' '
+		let l:cmd .= gutentags#get_execute_cmd_suffix()
+	endif
+	return l:cmd
+endfunction
+
 function! gutentags#gtags_cscope#generate(proj_dir, db_file, write_mode) abort
-	let l:db_path = fnamemodify(a:db_file, ':p:h')
-
-	let l:cmd = gutentags#get_execute_cmd()
 	" gtags doesn't honour GTAGSDBPATH and GTAGSROOT, so PWD and dbpath
 	" have to be set
+	let l:db_path = fnamemodify(a:db_file, ':p:h')
 
 	let l:proj_options_file = a:proj_dir . '/' . g:gutentags_gtags_options_file
-	let l:proj_options = ''
+	let l:proj_options = []
 	if filereadable(l:proj_options_file)
-		let l:lines = readfile(l:proj_options_file)
-		let l:proj_options .= join(l:lines, ' ')
+		let l:proj_options = readfile(l:proj_options_file)
 	endif
 
-	let l:cmd .= ' PWD=' . a:proj_dir
-	let l:cmd .= ' ' . g:gutentags_gtags_executable
-	let l:cmd .= ' ' . l:proj_options
-	let l:cmd .= ' --incremental '
-	let l:cmd .= ' --quiet '
-	let l:cmd .= ' ' . l:db_path
-	let l:cmd .= ' '
-	let l:cmd .= gutentags#get_execute_cmd_suffix()
+	let l:use_jobs = has('job')
 
-	call gutentags#trace("Running: " . l:cmd)
-	call gutentags#trace("In:      " . getcwd())
-	if !g:gutentags_fake
-		if !(has('nvim') && exists('*jobwait'))
-			if !g:gutentags_trace
-				silent execute l:cmd
-			else
-				execute l:cmd
-			endif
+	let l:prev_cwd = getcwd()
+	execute "chdir " . fnameescape(a:proj_dir)
+	try
+		if has('win32')
+			let l:cmd = s:get_win32_cmd(l:use_jobs, l:proj_options, l:db_path)
 		else
-			let job_dict = { 'db_file': a:db_file }
-			let job_cmd = l:cmd
-			let job_id = jobstart(job_cmd, job_dict)
+			let l:cmd = s:get_unix_cmd(l:use_jobs, l:proj_options, l:db_path)
 		endif
 
-		let l:full_gtags_file = fnamemodify(l:db_path, ':p')
-		call gutentags#add_progress('gtags_cscope', a:db_file)
-	else
-		call gutentags#trace("(fake... not actually running)")
-	endif
-	call gutentags#trace("")
+		call gutentags#trace("Running: " . string(l:cmd))
+		call gutentags#trace("In:      " . getcwd())
+		if !g:gutentags_fake
+			if l:use_jobs
+				let l:job_opts = {
+							\'exit_cb': 'gutentags#gtags_cscope#on_job_exit',
+							\'out_cb': 'gutentags#gtags_cscope#on_job_out',
+							\'err_cb': 'gutentags#gtags_cscope#on_job_out'
+							\}
+				let l:job = job_start(l:cmd, job_opts)
+				call add(s:job_db_files, [l:job, a:db_file])
+			else
+				if !g:gutentags_trace
+					silent execute l:cmd
+				else
+					execute l:cmd
+				endif
+				if g:gutentags_auto_add_gtags_cscope
+					call s:add_db(a:db_file)
+				endif
+			endif
+
+			let l:full_gtags_file = fnamemodify(l:db_path, ':p')
+			call gutentags#add_progress('gtags_cscope', a:db_file)
+		else
+			call gutentags#trace("(fake... not actually running)")
+		endif
+		call gutentags#trace("")
+    finally
+        " Restore the previous working directory.
+        execute "chdir " . fnameescape(l:prev_cwd)
+    endtry
 endfunction
 
 " }}}