contrib: make simplemerge script pass context-like objects

`simplemerge()` will soon require context-like objects to work. Create a simple
context-like object that wraps the requested files and can be passed to the new
API.

Differential Revision: https://phab.mercurial-scm.org/D378

contrib/simplemerge

@@ -1,75 +1,104 b''
 #!/usr/bin/env python
 from __future__ import absolute_import
 
 import getopt
 import sys
 
 import hgdemandimport
 hgdemandimport.enable()
 
 from mercurial.i18n import _
 from mercurial import (
     error,
     fancyopts,
     simplemerge,
     ui as uimod,
     util,
 )
 
 options = [('L', 'label', [], _('labels to use on conflict markers')),
            ('a', 'text', None, _('treat all files as text')),
            ('p', 'print', None,
             _('print results instead of overwriting LOCAL')),
            ('', 'no-minimal', None, _('no effect (DEPRECATED)')),
            ('h', 'help', None, _('display help and exit')),
            ('q', 'quiet', None, _('suppress output'))]
 
 usage = _('''simplemerge [OPTS] LOCAL BASE OTHER
 
     Simple three-way file merge utility with a minimal feature set.
 
     Apply to LOCAL the changes necessary to go from BASE to OTHER.
 
     By default, LOCAL is overwritten with the results of this operation.
 ''')
 
 class ParseError(Exception):
     """Exception raised on errors in parsing the command line."""
 
 def showhelp():
     sys.stdout.write(usage)
     sys.stdout.write('\noptions:\n')
 
     out_opts = []
     for shortopt, longopt, default, desc in options:
         out_opts.append(('%2s%s' % (shortopt and '-%s' % shortopt,
                                     longopt and ' --%s' % longopt),
                          '%s' % desc))
     opts_len = max([len(opt[0]) for opt in out_opts])
     for first, second in out_opts:
         sys.stdout.write(' %-*s  %s\n' % (opts_len, first, second))
 
+class filebackedctx(object):
+    """simplemerge requires context-like objects"""
+    def __init__(self, path):
+        self._path = path
+
+    def decodeddata(self):
+        with open(self._path, "rb") as f:
+            return f.read()
+
+    def flags(self):
+        return ''
+
+    def path(self):
+        return self._path
+
+    def write(self, data, flags):
+        assert not flags
+        with open(self._path, "w") as f:
+            f.write(data)
+
 try:
     for fp in (sys.stdin, sys.stdout, sys.stderr):
         util.setbinary(fp)
 
     opts = {}
     try:
         args = fancyopts.fancyopts(sys.argv[1:], options, opts)
     except getopt.GetoptError as e:
         raise ParseError(e)
     if opts['help']:
         showhelp()
         sys.exit(0)
     if len(args) != 3:
             raise ParseError(_('wrong number of arguments'))
-    sys.exit(simplemerge.simplemerge(uimod.ui.load(), *args, **opts))
+    local, base, other = args
+    sys.exit(simplemerge.simplemerge(uimod.ui.load(),
+                                     local,
+                                     base,
+                                     other,
+                                     filebackedctx(local),
+                                     filebackedctx(base),
+                                     filebackedctx(other),
+                                     filtereddata=True,
+                                     **opts))
 except ParseError as e:
     sys.stdout.write("%s: %s\n" % (sys.argv[0], e))
     showhelp()
     sys.exit(1)
 except error.Abort as e:
     sys.stderr.write("abort: %s\n" % e)
     sys.exit(255)
 except KeyboardInterrupt:
     sys.exit(255)