feat(latexmk): add support for aux_dir

refer: #2534

autoload/vimtex/compiler/latexmk.vim

@@ -82,6 +82,7 @@ endfunction
 
 let s:compiler = vimtex#compiler#_template#new({
       \ 'name' : 'latexmk',
+      \ 'aux_dir': '',
       \ 'callback' : 1,
       \ 'continuous': 1,
       \ 'executable' : 'latexmk',
@@ -102,17 +103,22 @@ endfunction
 
 " }}}1
 function! s:compiler.__init() abort dict " {{{1
-  " Check if .latexmkrc sets the out_dir - if so this should be respected
-  let l:out_dir =
-        \ vimtex#compiler#latexmk#get_rc_opt(self.state.root, 'out_dir', 0, '')[0]
-  if !empty(l:out_dir)
-    if !empty(self.out_dir) && (self.out_dir !=# l:out_dir)
+  call vimtex#util#materialize_property(self, 'aux_dir')
+
+  call s:compare_with_latexmkrc(self, 'out_dir')
+  call s:compare_with_latexmkrc(self, 'aux_dir')
+
+  " $VIMTEX_OUTPUT_DIRECTORY overrides configured compiler.aux_dir
+  if !empty($VIMTEX_OUTPUT_DIRECTORY)
+    if !empty(self.aux_dir)
+          \ && (self.aux_dir !=# $VIMTEX_OUTPUT_DIRECTORY)
       call vimtex#log#warning(
-            \ 'Setting out_dir from latexmkrc overrides out_dir!',
-            \ 'Changed out_dir from: ' . self.out_dir,
-            \ 'Changed out_dir to: ' . l:out_dir)
+            \ 'Setting VIMTEX_OUTPUT_DIRECTORY overrides aux_dir!',
+            \ 'Changed aux_dir from: ' . self.aux_dir,
+            \ 'Changed aux_dir to: ' . $VIMTEX_OUTPUT_DIRECTORY)
     endif
-    let self.out_dir = l:out_dir
+
+    let self.aux_dir = $VIMTEX_OUTPUT_DIRECTORY
   endif
 endfunction
 
@@ -129,6 +135,11 @@ function! s:compiler.__build_cmd() abort dict " {{{1
     let l:cmd .= ' -outdir=' . fnameescape(self.out_dir)
   endif
 
+  if !empty(self.aux_dir)
+    let l:cmd .= ' -emulate-aux-dir'
+    let l:cmd .= ' -auxdir=' . fnameescape(self.aux_dir)
+  endif
+
   if self.continuous
     let l:cmd .= ' -pvc -view=none'
 
@@ -148,21 +159,70 @@ endfunction
 
 " }}}1
 function! s:compiler.__pprint_append() abort dict " {{{1
-  return [
-        \ ['callback', self.callback],
-        \ ['continuous', self.continuous],
-        \ ['executable', self.executable],
+  let l:list = []
+
+  if !empty(self.aux_dir)
+    call add(l:list, ['aux_dir', self.aux_dir])
+  endif
+
+  call add(l:list, ['callback', self.callback])
+  call add(l:list, ['continuous', self.continuous])
+  call add(l:list, ['executable', self.executable])
+
+  return l:list
+endfunction
+
+" }}}1
+
+function! s:compiler.get_file(ext) abort dict " {{{1
+  for l:root in [
+        \ $VIMTEX_OUTPUT_DIRECTORY,
+        \ self.aux_dir,
+        \ self.out_dir,
+        \ self.state.root
         \]
+    if empty(l:root) | continue | endif
+
+    let l:cand = printf('%s/%s.%s', l:root, self.state.name, a:ext)
+    if !vimtex#paths#is_abs(l:root)
+      let l:cand = self.state.root . '/' . l:cand
+    endif
+
+    if filereadable(l:cand)
+      return fnamemodify(l:cand, ':p')
+    endif
+  endfor
+
+  return ''
+endfunction
+
+" }}}1
+function! s:compiler.create_dirs() abort dict " {{{1
+  call self._create_build_dir(self.out_dir)
+  call self._create_build_dir(self.aux_dir)
+endfunction
+
+" }}}1
+function! s:compiler.remove_dirs() abort dict " {{{1
+  call self._remove_dir(self.out_dir)
+  call self._remove_dir(self.aux_dir)
 endfunction
 
 " }}}1
 
 function! s:compiler.clean(full) abort dict " {{{1
-  let l:cmd = self.executable . ' ' . (a:full ? '-C ' : '-c ')
+  let l:cmd = self.executable
+  let l:cmd .= a:full ? ' -C' : ' -c'
+
   if !empty(self.out_dir)
-    let l:cmd .= printf(' -outdir=%s ', fnameescape(self.out_dir))
+    let l:cmd .= ' -outdir=' . fnameescape(self.out_dir)
+  endif
+  if !empty(self.aux_dir)
+    let l:cmd .= ' -emulate-aux'
+    let l:cmd .= ' -auxdir=' . fnameescape(self.aux_dir)
   endif
-  let l:cmd .= vimtex#util#shellescape(self.state.base)
+
+  let l:cmd .= ' ' . vimtex#util#shellescape(self.state.base)
 
   call vimtex#jobs#run(l:cmd, {'cwd': self.state.root})
 endfunction
@@ -173,7 +233,6 @@ function! s:compiler.get_engine() abort dict " {{{1
   let l:tex_program_directive = self.state.get_tex_program()
   let l:tex_program = l:tex_program_directive
 
-
   " Parse tex_program from from pdf_mode option in .latexmkrc
   let [l:pdf_mode, l:is_local] =
         \ vimtex#compiler#latexmk#get_rc_opt(self.state.root, 'pdf_mode', 1, -1)
@@ -209,6 +268,23 @@ endfunction
 " }}}1
 
 
+function! s:compare_with_latexmkrc(dict, option) abort " {{{1
+  " Check if option is specified in .latexmkrc.
+  " If it is, .latexmkrc should be respected!
+  let l:value = vimtex#compiler#latexmk#get_rc_opt(
+        \ a:dict.state.root, a:option, 0, '')[0]
+  if !empty(l:value)
+    if !empty(a:dict[a:option]) && (a:dict[a:option] !=# l:value)
+      call vimtex#log#warning(
+            \ 'Option "' . a:option . '" is overriden by latexmkrc',
+            \ 'Changed from: ' . a:dict[a:option],
+            \ 'Changed to: ' . l:value)
+    endif
+    let a:dict[a:option] = l:value
+  endif
+endfunction
+
+" }}}1
 function! s:wrap_option_appendcmd(name, value) abort " {{{1
   " Note: On Linux, we use double quoted perl strings; these interpolate
   "       variables. One should therefore NOT pass values that contain `$`.