Make xolox#misc#os#exec() report exit codes (breaks backwards compatibility)

Working towards fixing this issue: xolox/vim-lua-ftplugin#8

Author: xolox

autoload/xolox/misc/compat.vim

@@ -1,13 +1,13 @@
 " Vim auto-load script
 " Author: Peter Odding <peter@peterodding.com>
-" Last Change: April 28, 2013
+" Last Change: May 13, 2013
 " URL: http://peterodding.com/code/vim/misc/
 
 " The following integer will be bumped whenever a change in the miscellaneous
 " scripts breaks backwards compatibility. This enables my Vim plug-ins to fail
 " early when they detect an incompatible version, instead of breaking at the
 " worst possible moments :-).
-let g:xolox#misc#compat#version = 2
+let g:xolox#misc#compat#version = 3
 
 " Remember the directory where the miscellaneous scripts are loaded from
 " so the user knows which plug-in to update if incompatibilities arise.

autoload/xolox/misc/os.vim

@@ -1,29 +1,117 @@
 " Vim auto-load script
 " Author: Peter Odding <peter@peterodding.com>
-" Last Change: November 24, 2011
+" Last Change: May 13, 2013
 " URL: http://peterodding.com/code/vim/misc/
 
-let g:xolox#misc#os#version = '0.1'
+let g:xolox#misc#os#version = '0.2'
 
-" Check whether Vim is running on Microsoft Windows.
-
-function! xolox#misc#os#is_win()
+function! xolox#misc#os#is_win() " {{{1
+  " Check whether Vim is running on Microsoft Windows.
   return has('win16') || has('win32') || has('win64')
 endfunction
 
-" Execute an external command (hiding the console on Windows when possible).
-
-function! xolox#misc#os#exec(cmdline, ...)
+function! xolox#misc#os#exec(options) " {{{1
+  " Execute an external command (hiding the console on Windows when possible).
+  " NB: Everything below is wrapped in a try/finally block to guarantee
+  " cleanup of temporary files.
   try
-    " Try using my shell.vim plug-in.
-    return call('xolox#shell#execute', [a:cmdline, 1] + a:000)
-  catch /^Vim\%((\a\+)\)\=:E117/
-    " Fall back to system() when we get an "unknown function" error.
-    let output = call('system', [a:cmdline] + a:000)
-    if v:shell_error
-      throw printf("os.vim %s: Command %s failed: %s", g:xolox#misc#os#version, a:cmdline, xolox#misc#str#trim(output))
+
+    " Unpack the options.
+    let cmd = a:options['command']
+    let async = get(a:options, 'async', 0)
+
+    " Write the input for the external command to a temporary file?
+    if has_key(a:options, 'stdin')
+      let tempin = tempname()
+      if type(a:options['stdin']) == type([])
+        let lines = a:options['stdin']
+      else
+        let lines = split(a:options['stdin'], "\n")
+      endif
+      call writefile(lines, tempin)
+      let cmd .= ' < ' . xolox#misc#escape#shell(tempin)
+    endif
+
+    " Redirect the standard output and standard error streams of the external
+    " process to temporary files? (only in synchronous mode, which is the
+    " default).
+    if !async
+      let tempout = tempname()
+      let temperr = tempname()
+      let cmd = printf('(%s) 1>%s 2>%s', cmd,
+            \ xolox#misc#escape#shell(tempout),
+            \ xolox#misc#escape#shell(temperr))
+    endif
+
+    " If A) we're on Windows, B) the vim-shell plug-in is installed and C) the
+    " compiled DLL works, we'll use that because it's the most user friendly
+    " method. If the plug-in is not installed Vim will raise the exception
+    " "E117: Unknown function" which is caught and handled below.
+    try
+      if xolox#shell#can_use_dll()
+        " Let the user know what's happening (in case they're interested).
+        call xolox#misc#msg#debug("os.vim %s: Executing external command using compiled DLL: %s", g:xolox#misc#os#version, cmd)
+        let exit_code = xolox#shell#execute_with_dll(cmd, async)
+      endif
+    catch /^Vim\%((\a\+)\)\=:E117/
+      call xolox#misc#msg#debug("os.vim %s: The vim-shell plug-in is not installed, falling back to system() function.", g:xolox#misc#os#version)
+    endtry
+
+    " If we cannot use the DLL, we fall back to the default and generic
+    " implementation using Vim's system() function.
+    if !exists('exit_code')
+
+      " Enable asynchronous mode (very platform specific).
+      if async
+        if xolox#misc#os#is_win()
+          let cmd = 'start /b ' . cmd
+        elseif has('unix')
+          let cmd = '(' . cmd . ') &'
+        else
+          call xolox#misc#msg#warn("os.vim %s: I don't know how to run commands asynchronously on your platform! Falling back to synchronous mode.", g:xolox#misc#os#version)
+        endif
+      endif
+
+      " Let the user know what's happening (in case they're interested).
+      call xolox#misc#msg#debug("os.vim %s: Executing external command using system() function: %s", g:xolox#misc#os#version, cmd)
+      call system(cmd)
+      let exit_code = v:shell_error
+
     endif
-    return split(output, "\n")
+
+    let result = {}
+    if !async
+      " If we just executed a synchronous command and the caller didn't
+      " specifically ask us *not* to check the exit code of the external
+      " command, we'll do so now.
+      if get(a:options, 'check', 1) && exit_code != 0
+        let msg = "os.vim %s: External command failed with exit code %d: %s"
+        throw printf(msg, g:xolox#misc#os#version, result['exit_code'], result['command'])
+      endif
+      " Return the results as a dictionary with three key/value pairs.
+      let result['exit_code'] = exit_code
+      let result['stdout'] = s:readfile(tempout)
+      let result['stderr'] = s:readfile(temperr)
+    endif
+    return result
+
+  finally
+    " Cleanup any temporary files we created.
+    for name in ['tempin', 'tempout', 'temperr']
+      if exists(name)
+        call delete({name})
+      endif
+    endfor
+  endtry
+
+endfunction
+
+function! s:readfile(fname) " {{{1
+  " readfile() that swallows errors.
+  try
+    return readfile(a:fname)
+  catch
+    return []
   endtry
 endfunction