infinitepush: fix `{get,put}_args` formatting on Python 3

Calling `.format()` on a byte-string does not work, thus
causing an exception on Python 3. This commit adds a function
to paper over the difference.

Differential Revision: https://phab.mercurial-scm.org/D8781

hgext/infinitepush/store.py

@@ -1,183 +1,198 b''
 # This software may be used and distributed according to the terms of the
 # GNU General Public License version 2 or any later version.
 
 # based on bundleheads extension by Gregory Szorc <[e-mail]>
 
 from __future__ import absolute_import
 
 import abc
 import os
 import subprocess
 import tempfile
 
 from mercurial.pycompat import open
 from mercurial import (
     node,
     pycompat,
 )
 from mercurial.utils import (
     hashutil,
     procutil,
 )
 
 
 class BundleWriteException(Exception):
     pass
 
 
 class BundleReadException(Exception):
     pass
 
 
 class abstractbundlestore(object):  # pytype: disable=ignored-metaclass
     """Defines the interface for bundle stores.
 
     A bundle store is an entity that stores raw bundle data. It is a simple
     key-value store. However, the keys are chosen by the store. The keys can
     be any Python object understood by the corresponding bundle index (see
     ``abstractbundleindex`` below).
     """
 
     __metaclass__ = abc.ABCMeta
 
     @abc.abstractmethod
     def write(self, data):
         """Write bundle data to the store.
 
         This function receives the raw data to be written as a str.
         Throws BundleWriteException
         The key of the written data MUST be returned.
         """
 
     @abc.abstractmethod
     def read(self, key):
         """Obtain bundle data for a key.
 
         Returns None if the bundle isn't known.
         Throws BundleReadException
         The returned object should be a file object supporting read()
         and close().
         """
 
 
 class filebundlestore(object):
     """bundle store in filesystem
 
     meant for storing bundles somewhere on disk and on network filesystems
     """
 
     def __init__(self, ui, repo):
         self.ui = ui
         self.repo = repo
         self.storepath = ui.configpath(b'scratchbranch', b'storepath')
         if not self.storepath:
             self.storepath = self.repo.vfs.join(
                 b"scratchbranches", b"filebundlestore"
             )
         if not os.path.exists(self.storepath):
             os.makedirs(self.storepath)
 
     def _dirpath(self, hashvalue):
         """First two bytes of the hash are the name of the upper
         level directory, next two bytes are the name of the
         next level directory"""
         return os.path.join(self.storepath, hashvalue[0:2], hashvalue[2:4])
 
     def _filepath(self, filename):
         return os.path.join(self._dirpath(filename), filename)
 
     def write(self, data):
         filename = node.hex(hashutil.sha1(data).digest())
         dirpath = self._dirpath(filename)
 
         if not os.path.exists(dirpath):
             os.makedirs(dirpath)
 
         with open(self._filepath(filename), b'wb') as f:
             f.write(data)
 
         return filename
 
     def read(self, key):
         try:
             with open(self._filepath(key), b'rb') as f:
                 return f.read()
         except IOError:
             return None
 
 
+def format_placeholders_args(args, filename=None, handle=None):
+    """Formats `args` with Infinitepush replacements.
+
+    Hack to get `str.format()`-ed strings working in a BC way with
+    bytes.
+    """
+    formatted_args = []
+    for arg in args:
+        if filename and arg == b'{filename}':
+            formatted_args.append(filename)
+        elif handle and arg == b'{handle}':
+            formatted_args.append(handle)
+        else:
+            formatted_args.append(arg)
+    return formatted_args
+
+
 class externalbundlestore(abstractbundlestore):
     def __init__(self, put_binary, put_args, get_binary, get_args):
         """
         `put_binary` - path to binary file which uploads bundle to external
             storage and prints key to stdout
         `put_args` - format string with additional args to `put_binary`
                      {filename} replacement field can be used.
         `get_binary` - path to binary file which accepts filename and key
             (in that order), downloads bundle from store and saves it to file
         `get_args` - format string with additional args to `get_binary`.
                      {filename} and {handle} replacement field can be used.
         """
 
         self.put_args = put_args
         self.get_args = get_args
         self.put_binary = put_binary
         self.get_binary = get_binary
 
     def _call_binary(self, args):
         p = subprocess.Popen(
             pycompat.rapply(procutil.tonativestr, args),
             stdout=subprocess.PIPE,
             stderr=subprocess.PIPE,
             close_fds=True,
         )
         stdout, stderr = p.communicate()
         returncode = p.returncode
         return returncode, stdout, stderr
 
     def write(self, data):
         # Won't work on windows because you can't open file second time without
         # closing it
         # TODO: rewrite without str.format() and replace NamedTemporaryFile()
         # with pycompat.namedtempfile()
         with pycompat.namedtempfile() as temp:
             temp.write(data)
             temp.flush()
             temp.seek(0)
-            formatted_args = [
-                arg.format(filename=temp.name) for arg in self.put_args
-            ]
+            formatted_args = format_placeholders_args(
+                self.put_args, filename=temp.name
+            )
             returncode, stdout, stderr = self._call_binary(
                 [self.put_binary] + formatted_args
             )
 
             if returncode != 0:
                 raise BundleWriteException(
                     b'Failed to upload to external store: %s' % stderr
                 )
             stdout_lines = stdout.splitlines()
             if len(stdout_lines) == 1:
                 return stdout_lines[0]
             else:
                 raise BundleWriteException(
                     b'Bad output from %s: %s' % (self.put_binary, stdout)
                 )
 
     def read(self, handle):
         # Won't work on windows because you can't open file second time without
         # closing it
-        # TODO: rewrite without str.format()
         with pycompat.namedtempfile() as temp:
-            formatted_args = [
-                arg.format(filename=temp.name, handle=handle)
-                for arg in self.get_args
-            ]
+            formatted_args = format_placeholders_args(
+                self.get_args, filename=temp.name, handle=handle
+            )
             returncode, stdout, stderr = self._call_binary(
                 [self.get_binary] + formatted_args
             )
 
             if returncode != 0:
                 raise BundleReadException(
                     b'Failed to download from external store: %s' % stderr
                 )
             return temp.read()