Open same file read-only in second Vim

Tip 847 Printable Monobook Previous Next

created January 9, 2005 · complexity basic · author Jang Junyeong · version 6.0

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When you open a file opened in somewhere else, you would get "E325: ATTENTION" message because a swap file already exists there. I (almost) always choose the action "[O]pen Read-Only" in this case, so typing 'O' key is an annoying job for me. The following in my vimrc reduce my job.

func CheckSwap()
  swapname
  if v:statusmsg =~ '\.sw[^p]$'
    set ro
  endif
endfunc

if &swf
  set shm+=A
  au BufReadPre * call CheckSwap()
endif

Comments

Very neat trick. However, in a genuine case (when a previous session really crashed), the message is still usefull, and avoiding it could cause some confusion later. Also, you might want to recover the file immediately too. To address this issue, here is a modified attempt that echoes a message in this case. The message is hopefully easier to digest than the original ATTENTION dialog.

I improved it slighly more with a toggle option. If you want to delete the swapfile, it is easier to have Vim do it, so I added a ToggleSwapCheck() function. I usage is to toggle the behavior, reload the buffer to get the Vim dialog box where you can choose to delete the swap. You can later toggle it back on by calling the same function.

let s:swapCheckEnabled = 0
let s:_shm = &shm
function! ToggleSwapCheck()
  let s:swapCheckEnabled = !s:swapCheckEnabled
  if !s:swapCheckEnabled
    let &shm = s:_shm
  endif
  aug CheckSwap
    au!
    if s:swapCheckEnabled
      set shm+=A
      au BufReadPre * call CheckSwapFile()
      au BufRead * call WarnSwapFile()
    endif
  aug END
endfunction
call ToggleSwapCheck()

function! CheckSwapFile()
  if !exists('*GetVimCmdOutput') || !&swapfile || !s:swapCheckEnabled
    return
  endif

  let swapname = GetVimCmdOutput('swapname')
  if swapname =~ '\.sw[^p]$'
    set ro
    let b:_warnSwap = 1
  endif
endfunction

function! WarnSwapFile()
  if exists('b:_warnSwap') && b:_warnSwap && &swapfile
    echohl ErrorMsg | echomsg "File: \"" . bufname('%') .
     \ "\" is opened readonly, as a swapfile already existed."
     \ | echohl NONE
    unlet b:_warnSwap
  endif
endfunction

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