ext.spawn: Refactor

Rename `spawn` to `check_output`
Mimic `subprocess.check_output`

4 files changed, 42 insertions, 57 deletions

diff --git a/ranger/container/fsobject.py b/ranger/container/fsobject.py
index d73fa76c..9b312e6d 100644
--- a/ranger/container/fsobject.py
+++ b/ranger/container/fsobject.py
@@ -20,7 +20,7 @@ from pwd import getpwuid
 from ranger.core.linemode import *
 from ranger.core.shared import FileManagerAware, SettingsAware
 from ranger.ext.shell_escape import shell_escape
-from ranger.ext.spawn import spawn
+from ranger.ext import spawn
 from ranger.ext.lazy_property import lazy_property
 from ranger.ext.human_readable import human_readable
 
@@ -131,7 +131,7 @@ class FileSystemObject(FileManagerAware, SettingsAware):
     @lazy_property
     def filetype(self):
         try:
-            return spawn(["file", '-Lb', '--mime-type', self.path])
+            return spawn.check_output(["file", '-Lb', '--mime-type', self.path])
         except OSError:
             return ""
 
diff --git a/ranger/core/linemode.py b/ranger/core/linemode.py
index a8ce4e6d..c7839723 100644
--- a/ranger/core/linemode.py
+++ b/ranger/core/linemode.py
@@ -7,7 +7,7 @@ import sys
 from abc import *
 from datetime import datetime
 from ranger.ext.human_readable import human_readable
-from ranger.ext.spawn import spawn
+from ranger.ext import spawn
 
 DEFAULT_LINEMODE = "filename"
 
@@ -100,7 +100,7 @@ class FileInfoLinemode(LinemodeBase):
         if not file.is_directory:
             from subprocess import Popen, PIPE, CalledProcessError
             try:
-                fileinfo = spawn(["file", "-bL", file.path]).strip()
+                fileinfo = spawn.check_output(["file", "-bL", file.path]).strip()
             except CalledProcessError:
                 return "unknown"
             if sys.version_info[0] >= 3:
diff --git a/ranger/ext/spawn.py b/ranger/ext/spawn.py
index 393d48d9..77983341 100644
--- a/ranger/ext/spawn.py
+++ b/ranger/ext/spawn.py
@@ -1,57 +1,44 @@
 # This file is part of ranger, the console file manager.
 # License: GNU GPL version 3, see the file "AUTHORS" for details.
 
+from os import devnull
 from subprocess import Popen, PIPE, CalledProcessError
 ENCODING = 'utf-8'
 
 
-def spawn(*args, **kwargs):
-    """Runs a program, waits for its termination and returns its stdout
+def check_output(popenargs, **kwargs):
+    """Runs a program, waits for its termination and returns its output
 
-    This function is similar to python 2.7's subprocess.check_output,
+    This function is functionally identical to python 2.7's subprocess.check_output,
     but is favored due to python 2.6 compatibility.
 
-    The arguments may be:
+    Will be run through shell if popenargs is a string, otherwise the command
+    is executed directly.
 
-        spawn(string)
-        spawn(command, arg1, arg2...)
-        spawn([command, arg1, arg2])
-
-    The string will be run through a shell, otherwise the command is executed
-    directly.
-
-    The keyword argument "decode" determines if the output shall be decoded
-    with the encoding '%s'.
+    The keyword argument `decode` determines if the output shall be decoded
+    with the encoding ENCODING.
 
     Further keyword arguments are passed to Popen.
-    """ % (ENCODING, )
+    """
 
-    if len(args) == 1:
-        popen_arguments = args[0]
-        shell = isinstance(popen_arguments, str)
-    else:
-        popen_arguments = args
-        shell = False
+    do_decode = kwargs.pop('decode', True)
+    kwargs.setdefault('stdout', PIPE)
+    kwargs.setdefault('shell', isinstance(popenargs, str))
 
-    if 'decode' in kwargs:
-        do_decode = kwargs['decode']
-        del kwargs['decode']
+    if 'stderr' in kwargs:
+        process = Popen(popenargs, **kwargs)
+        stdout, _ = process.communicate()
     else:
-        do_decode = True
-    if 'stdout' not in kwargs:
-        kwargs['stdout'] = PIPE
-    if 'shell' not in kwargs:
-        kwargs['shell'] = shell
-
-    process = Popen(popen_arguments, **kwargs)
-    stdout, stderr = process.communicate()
-    return_value = process.poll()
-    if return_value:
-        error = CalledProcessError(return_value, popen_arguments[0])
+        with open(devnull, mode='w') as fd_devnull:
+            process = Popen(popenargs, stderr=fd_devnull, **kwargs)
+            stdout, _ = process.communicate()
+
+    if process.returncode != 0:
+        error = CalledProcessError(process.returncode, popenargs)
         error.output = stdout
         raise error
 
-    if do_decode:
-        return stdout.decode(ENCODING)
-    else:
-        return stdout
+    if do_decode and stdout is not None:
+        stdout = stdout.decode(ENCODING)
+
+    return stdout
diff --git a/ranger/ext/vcs/vcs.py b/ranger/ext/vcs/vcs.py
index 9c2a8b5a..03a72bb4 100644
--- a/ranger/ext/vcs/vcs.py
+++ b/ranger/ext/vcs/vcs.py
@@ -8,7 +8,8 @@ import subprocess
 import threading
 import time
 from logging import getLogger
-from ranger.ext.spawn import spawn
+
+from ranger.ext import spawn
 
 # Python2 compatibility
 try:
@@ -119,20 +120,17 @@ class Vcs(object):  # pylint: disable=too-many-instance-attributes
         if path is None:
             path = self.path
 
-        with open(os.devnull, 'w') as devnull:
-            try:
-                if catchout:
-                    output = spawn(cmd, cwd=path, stderr=devnull,
-                            decode=not retbytes)
-                    if (not retbytes and rstrip_newline and
-                            output.endswith('\n')):
-                        if rstrip_newline and output.endswith('\n'):
-                            return output[:-1]
-                    return output
-                else:
-                    subprocess.check_call(cmd, cwd=path, stdout=devnull, stderr=devnull)
-            except (subprocess.CalledProcessError, FileNotFoundError):
-                raise VcsError('{0:s}: {1:s}'.format(str(cmd), path))
+        try:
+            if catchout:
+                output = spawn.check_output(cmd, cwd=path, decode=not retbytes)
+                if not retbytes and rstrip_newline and output.endswith('\n'):
+                    return output[:-1]
+                return output
+            else:
+                with open(os.devnull, mode='w') as fd_devnull:
+                    subprocess.check_call(cmd, cwd=path, stdout=fd_devnull, stderr=fd_devnull)
+        except (subprocess.CalledProcessError, FileNotFoundError):
+            raise VcsError('{0:s}: {1:s}'.format(str(cmd), path))
 
     def _get_repotype(self, path):
         """Get type for path"""