Support compare two files (wrapper of diff)

CHANGES

 Change log
 ==========
 
+Version 0.3 (2013-02-07)
+
+  - Support compare two files (wrapper of diff)
+
 Version 0.2 (2013-02-06)
 
   - Move cdiff.py to top dir for better meta info management

README.rst

 =====
 
 Term based tool to view **colored**, **incremental** diff in *git/svn/hg*
-workspace, or diff from given file or stdin, with **side by side** and **auto
-pager** support.  Requires python (>= 2.5.0) and ``less``.
+workspace, given patch or two files, or from stdin, with **side by side** and
+**auto pager** support.  Requires python (>= 2.5.0) and ``less``.
 
 .. image:: http://ymattw.github.com/cdiff/img/default.png
    :alt: default
 .. code:: sh
 
     git log -p -2 | cdiff -s
-    git show 15bfa56 | cdiff -s
+    git show 15bfa5 | cdiff -s
     svn diff -r PREV | cdiff -s
-    diff -u foo foo.new | cdiff -s
 
 View a diff (patch) file:
 
     cdiff foo.patch -s
     cdiff foo.patch -s -w 90
 
+View diff between two files (wrapper of ``diff``)::
+
+    cdiff foo foo.new       # equivalent to diff -u foo foo.new | cdiff
+    cdiff foo foo.new -s
+
 Redirect output to another patch file is safe:
 
 .. code:: sh

cdiff.py

 
 """
 Term based tool to view **colored**, **incremental** diff in *git/svn/hg*
-workspace, given file or stdin, with **side by side** and **auto pager**
-support.  Requires python (>= 2.5.0) and ``less``.
+workspace, given patch or two files, or from stdin, with **side by side** and
+**auto pager** support.  Requires python (>= 2.5.0) and ``less``.
 """
 
 META_INFO = {
-    'version'     : '0.2',
+    'version'     : '0.3',
     'license'     : 'BSD-3',
     'author'      : 'Matthew Wang',
     'email'       : 'mattwyl(@)gmail(.)com',
     'url'         : 'https://github.com/ymattw/cdiff',
     'keywords'    : 'colored incremental side-by-side diff',
-    'description' : ('View colored, incremental diff in workspace, given file '
-                     'or from stdin, with side by side and auto pager support')
+    'description' : ('View colored, incremental diff in workspace, given patch '
+                     'or two files, or from stdin, with side by side and  auto '
+                     'pager support')
 }
 
 import sys
 import difflib
 
 
-
 COLORS = {
     'reset'         : '\x1b[0m',
     'underline'     : '\x1b[4m',
 
     supported_vcs = [check[0] for check, _ in REVISION_CONTROL]
 
-    usage = '%prog [options] [diff]'
-    description= ('View colored, incremental diff in %s workspace, or diff '
-                  'from given file or stdin, with side by side and auto '
-                  'pager support') % '/'.join(supported_vcs)
-
-    parser = optparse.OptionParser(usage=usage, description=description,
+    usage = """
+  %prog [options]
+  %prog [options] <patch>
+  %prog [options] <file1> <file2>"""
+    parser = optparse.OptionParser(usage=usage,
+            description=META_INFO['description'],
             version='%%prog %s' % META_INFO['version'])
     parser.add_option('-s', '--side-by-side', action='store_true',
             help=('show in side-by-side mode'))
             help='set text width (side-by-side mode only), default is 80')
     opts, args = parser.parse_args()
 
-    if len(args) >= 1:
+    if len(args) > 2:
+        parser.print_help()
+        return 1
+    elif len(args) == 2:
+        diff_hdl = subprocess.Popen(['diff', '-u', args[0], args[1]],
+                stdout=subprocess.PIPE).stdout
+    elif len(args) == 1:
         if IS_PY3:
             # Python3 needs the newline='' to keep '\r' (DOS format)
             diff_hdl = open(args[0], mode='rt', newline='')
     # FIXME: can't use generator for now due to current implementation in parser
     stream = [decode(line) for line in diff_hdl.readlines()]
 
+    if diff_hdl is not sys.stdin:
+        diff_hdl.close()
+
     # Don't let empty diff pass thru
     if not stream:
         return 0
 
-    if diff_hdl is not sys.stdin:
-        diff_hdl.close()
-
     if sys.stdout.isatty():
         try:
             markup_to_pager(stream, opts)