Refactor to use *WriteCmd/*ReadCmd autocommands.

With this change, we're able to properly handle errors from shell commands.
This means no more overwriting the original file when an incorrect password is
entered or some other similar scenario.

Also, move the handling of entering recipients to gpg itself instead of
mimicking that in Vim itself.

Signed-off-by: James Vega <vega.james@gmail.com>

plugin/gnupg.vim

@@ -127,6 +127,7 @@ if (exists("g:loaded_gnupg") || &cp || exists("#BufReadPre#*.\(gpg\|asc\|pgp\)")
   finish
 endif
 let g:loaded_gnupg = "$Revision$"
+let s:GPGInitRun = 0
 
 " check for correct vim version {{{2
 if (v:version < 700)
@@ -143,19 +144,14 @@ endif
 augroup GnuPG
   autocmd!
 
-  " initialize the internal variables
-  autocmd BufNewFile,BufReadPre,FileReadPre      *.\(gpg\|asc\|pgp\) call s:GPGInit()
-  " force the user to edit the recipient list if he opens a new file and public
-  " keys are preferred
-  autocmd BufNewFile                             *.\(gpg\|asc\|pgp\) if (exists("g:GPGPreferSymmetric") && g:GPGPreferSymmetric == 0) | call s:GPGEditRecipients() | endif
   " do the decryption
-  autocmd BufReadPost,FileReadPost               *.\(gpg\|asc\|pgp\) call s:GPGDecrypt()
+  autocmd BufReadCmd,FileReadCmd                 *.\(gpg\|asc\|pgp\) call s:GPGInit()
+  autocmd BufReadCmd,FileReadCmd                 *.\(gpg\|asc\|pgp\) call s:GPGDecrypt()
+  autocmd BufReadCmd                             *.\(gpg\|asc\|pgp\) call s:GPGBufReadPost()
 
   " convert all text to encrypted text before writing
-  autocmd BufWritePre,FileWritePre               *.\(gpg\|asc\|pgp\) call s:GPGEncrypt()
+  autocmd BufWriteCmd,FileWriteCmd               *.\(gpg\|asc\|pgp\) call s:GPGInit()
-  " undo the encryption so we are back in the normal text, directly
+  autocmd BufWriteCmd,FileWriteCmd               *.\(gpg\|asc\|pgp\) call s:GPGEncrypt()
-  " after the file has been written.
-  autocmd BufWritePost,FileWritePost             *.\(gpg\|asc\|pgp\) call s:GPGEncryptPost()
 
   " cleanup on leaving vim
   autocmd VimLeave                               *.\(gpg\|asc\|pgp\) call s:GPGCleanup()
@@ -178,6 +174,9 @@ highlight default link GPGHighlightUnknownRecipient ErrorMsg
 " initialize the plugin
 "
 function s:GPGInit()
+  if s:GPGInitRun
+    return
+  endif
   call s:GPGDebug(3, ">>>>>>>> Entering s:GPGInit()")
 
   " first make sure nothing is written to ~/.viminfo while editing
@@ -185,7 +184,7 @@ function s:GPGInit()
   set viminfo=
 
   " we don't want a swap file, as it writes unencrypted data to disk
-  set noswapfile
+  setl noswapfile
 
   " check what gpg command to use
   if (!exists("g:GPGExecutable"))
@@ -296,6 +295,7 @@ function s:GPGInit()
   call s:GPGDebug(2, "hashing algorithms: " . s:GPGHash)
   call s:GPGDebug(2, "compression algorithms: " . s:GPGCompress)
   call s:GPGDebug(3, "<<<<<<<< Leaving s:GPGInit()")
+  let s:GPGInitRun = 1
 endfunction
 
 " Function: s:GPGCleanup() {{{2
@@ -319,11 +319,13 @@ endfunction
 function s:GPGDecrypt()
   call s:GPGDebug(3, ">>>>>>>> Entering s:GPGDecrypt()")
 
-  " switch to binary mode to read the encrypted file
-  set bin
-
   " get the filename of the current buffer
-  let filename = expand("%:p")
+  let filename = expand("<afile>:p")
+
+  " File doesn't exist yet, so force recipients
+  if empty(glob(filename))
+    return
+  endif
 
   " clear GPGEncrypted, GPGRecipients and GPGOptions
   let b:GPGEncrypted = 0
@@ -391,7 +393,7 @@ function s:GPGDecrypt()
     echohl GPGWarning
     echom "File is not encrypted, all GPG functions disabled!"
     echohl None
-    set nobin
+    silent exe '.r ' . fnameescape(filename)
     call s:GPGDebug(3, "<<<<<<<< Leaving s:GPGDecrypt()")
     return
   endif
@@ -406,7 +408,7 @@ function s:GPGDecrypt()
   " since even with the --quiet option passphrase typos will be reported,
   " we must redirect stderr (using shell temporarily)
   call s:GPGDebug(1, "decrypting file")
-  let commandline = "'[,']!" . s:GPGCommand . " --quiet --decrypt " . s:stderrredirnull
+  let commandline = "r !" . s:GPGCommand . ' --quiet --decrypt ' . shellescape(filename, 1) . ' ' . s:stderrredirnull
   call s:GPGDebug(1, "command: " . commandline)
   let &shellredir = s:shellredir
   let &shell = s:shell
@@ -414,29 +416,29 @@ function s:GPGDecrypt()
   let &shellredir = s:shellredirsave
   let &shell = s:shellsave
   if (v:shell_error) " message could not be decrypted
-    silent u
     echohl GPGError
     let blackhole = input("Message could not be decrypted! (Press ENTER)")
     echohl None
-    bwipeout
+    silent bwipeout!
-    set nobin
     call s:GPGDebug(3, "<<<<<<<< Leaving s:GPGDecrypt()")
     return
   endif
 
-  " turn off binary mode
-  set nobin
-
-  " call the autocommand for the file minus .gpg$
-  execute ":doautocmd BufReadPost " . fnameescape(expand("%:r"))
-  call s:GPGDebug(2, "called autocommand for " . fnameescape(expand("%:r")))
-
   " refresh screen
   redraw!
 
   call s:GPGDebug(3, "<<<<<<<< Leaving s:GPGDecrypt()")
 endfunction
 
+function s:GPGBufReadPost()
+  call s:GPGDebug(3, ">>>>>>>> Entering s:GPGBufReadPost()")
+  silent 1delete
+  " call the autocommand for the file minus .gpg$
+  execute ':doautocmd BufReadPost ' . fnameescape(expand('<afile>:r'))
+  call s:GPGDebug(2, 'called autocommand for ' . fnameescape(expand('<afile>:r')))
+  call s:GPGDebug(3, "<<<<<<<< Leaving s:GPGBufReadPost()")
+endfunction
+
 " Function: s:GPGEncrypt() {{{2
 "
 " encrypts the buffer to all previous recipients
@@ -444,10 +446,6 @@ endfunction
 function s:GPGEncrypt()
   call s:GPGDebug(3, ">>>>>>>> Entering s:GPGEncrypt()")
 
-  " save window view
-  let s:GPGWindowView = winsaveview()
-  call s:GPGDebug(2, "saved window view " . string(s:GPGWindowView))
-
   " store encoding and switch to a safe one
   if (&fileencoding != &encoding)
     let s:GPGEncoding = &encoding
@@ -458,13 +456,10 @@ function s:GPGEncrypt()
     call s:GPGDebug(2, "encoding and fileencoding are the same (\"" . &encoding . "\"), not switching")
   endif
 
-  " switch buffer to binary mode
-  set bin
-
   " guard for unencrypted files
-  if (!exists("b:GPGEncrypted") || b:GPGEncrypted == 0)
+  if (exists("b:GPGEncrypted") && b:GPGEncrypted == 0)
     echohl GPGError
-    let blackhole = input("Message could not be encrypted! File might be empty! (Press ENTER)")
+    let blackhole = input("Message could not be encrypted! (Press ENTER)")
     echohl None
     call s:GPGDebug(3, "<<<<<<<< Leaving s:GPGEncrypt()")
     return
@@ -494,6 +489,10 @@ function s:GPGEncrypt()
     let options = options . " --" . option . " "
   endfor
 
+  if (!exists('b:GPGRecipients'))
+    let b:GPGRecipients = []
+  endif
+
   " check here again if all recipients are available in the keyring
   let [ recipients, unknownrecipients ] = s:GPGCheckRecipients(b:GPGRecipients)
 
@@ -513,57 +512,17 @@ function s:GPGEncrypt()
     for gpgid in recipients
       let options = options . " -r " . gpgid
     endfor
-  else
-    if (match(b:GPGOptions, "encrypt") >= 0)
-      echohl GPGError
-      echom "There are no recipients!!"
-      echom "Please use GPGEditRecipients to correct!!"
-      echo
-      echohl None
-    endif
   endif
 
   " encrypt the buffer
-  let commandline = "'[,']!" . s:GPGCommand . " --quiet --no-encrypt-to " . options . " " . s:stderrredirnull
+  let destfile = tempname()
+  let commandline = "'[,']w !" . s:GPGCommand . ' --quiet --no-encrypt-to ' . options . '>' . shellescape(destfile, 1) . ' ' . s:stderrredirnull
   call s:GPGDebug(1, "command: " . commandline)
   let &shellredir = s:shellredir
   let &shell = s:shell
   silent execute commandline
   let &shellredir = s:shellredirsave
   let &shell = s:shellsave
-  if (v:shell_error) " message could not be encrypted
-    " delete content of the buffer to be sure no data is written unencrypted
-    " content will be recovered in GPGEncryptPost()
-    silent normal! 1GdG
-
-    echohl GPGError
-    let blackhole = input("Message could not be encrypted! File might be empty! (Press ENTER)")
-    echohl None
-    call s:GPGDebug(3, "<<<<<<<< Leaving s:GPGEncrypt()")
-    return
-  endif
-
-  call s:GPGDebug(3, "<<<<<<<< Leaving s:GPGEncrypt()")
-endfunction
-
-" Function: s:GPGEncryptPost() {{{2
-"
-" undo changes don by encrypt, after writing
-"
-function s:GPGEncryptPost()
-  call s:GPGDebug(3, ">>>>>>>> Entering s:GPGEncryptPost()")
-
-  " guard for unencrypted files
-  if (exists("b:GPGEncrypted") && b:GPGEncrypted == 0)
-    call s:GPGDebug(3, "<<<<<<<< Leaving s:GPGEncryptPost()")
-    return
-  endif
-
-  " undo encryption of buffer content
-  silent u
-
-  " switch back from binary mode
-  set nobin
 
   " restore encoding
   if (s:GPGEncoding != "")
@@ -571,14 +530,19 @@ function s:GPGEncryptPost()
     call s:GPGDebug(2, "restored encoding \"" . &encoding . "\"")
   endif
 
-  " restore window view
+  if (v:shell_error) " message could not be encrypted
-  call winrestview(s:GPGWindowView)
+    " Command failed, so clean up the tempfile
-  call s:GPGDebug(2, "restored window view" . string(s:GPGWindowView))
+    call delete(destfile)
+    echohl GPGError
+    let blackhole = input("Message could not be encrypted! (Press ENTER)")
+    echohl None
+    call s:GPGDebug(3, "<<<<<<<< Leaving s:GPGEncrypt()")
+    return
+  endif
 
-  " refresh screen
+  call rename(destfile, expand('<afile>'))
-  redraw!
+  setl nomodified
-
+  call s:GPGDebug(3, "<<<<<<<< Leaving s:GPGEncrypt()")
-  call s:GPGDebug(3, "<<<<<<<< Leaving s:GPGEncryptPost()")
 endfunction
 
 " Function: s:GPGViewRecipients() {{{2
@@ -667,7 +631,7 @@ function s:GPGEditRecipients()
       endif
 
       " empty the buffer
-      silent normal! 1GdG
+      silent %delete
     endif
 
     " Mark the buffer as a scratch buffer
@@ -732,10 +696,10 @@ function s:GPGEditRecipients()
     endif
 
     " delete the empty first line
-    silent normal! 1Gdd
+    silent 1delete
 
     " jump to the first recipient
-    silent normal! G
+    silent $
 
   endif
 
@@ -814,7 +778,7 @@ function s:GPGFinishRecipientsBuffer()
   endif
 
   " reset modified flag
-  set nomodified
+  setl nomodified
 
   call s:GPGDebug(3, "<<<<<<<< Leaving s:GPGFinishRecipientsBuffer()")
 endfunction
@@ -889,7 +853,7 @@ function s:GPGEditOptions()
       endif
 
       " empty the buffer
-      silent normal! 1GdG
+      silent %delete
     endif
 
     " Mark the buffer as a scratch buffer
@@ -921,10 +885,10 @@ function s:GPGEditOptions()
     endfor
 
     " delete the empty first line
-    silent normal! 1Gdd
+    silent 1delete
 
     " jump to the first option
-    silent normal! G
+    silent $
 
     " define highlight
     if (has("syntax") && exists("g:syntax_on"))
@@ -987,7 +951,7 @@ function s:GPGFinishOptionsBuffer()
   call setbufvar(b:GPGCorrespondingTo, "&mod", 1)
 
   " reset modified flag
-  set nomodified
+  setl nomodified
 
   call s:GPGDebug(3, "<<<<<<<< Leaving s:GPGFinishOptionsBuffer()")
 endfunction