bundle2: support bundling simple parameter

This changeset add bundling capacity for simple parameters, not value or any
special case are handled.

mercurial/bundle2.py

@@ -1,136 +1,165
 # bundle2.py - generic container format to transmit arbitrary data.
 #
 # Copyright 2013 Facebook, Inc.
 #
 # This software may be used and distributed according to the terms of the
 # GNU General Public License version 2 or any later version.
 """Handling of the new bundle2 format
 
 The goal of bundle2 is to act as an atomically packet to transmit a set of
 payloads in an application agnostic way. It consist in a sequence of "parts"
 that will be handed to and processed by the application layer.
 
 
 General format architecture
 ===========================
 
 The format is architectured as follow
 
  - magic string
  - stream level parameters
  - payload parts (any number)
  - end of stream marker.
 
-The current implementation is limited to empty bundle.
+The current implementation accept some stream level option but no part.
 
 Details on the Binary format
 ============================
 
 All numbers are unsigned and big endian.
 
 stream level parameters
 ------------------------
 
 Binary format is as follow
 
 :params size: (16 bits integer)
 
   The total number of Bytes used by the parameters
 
-  Currently force to 0.
-
 :params value: arbitrary number of Bytes
 
   A blob of `params size` containing the serialized version of all stream level
   parameters.
 
-  Currently always empty.
+  The blob contains a space separated list of parameters.
+
+  Parameter value are not supported yet.
+
+  Special character in param name are not supported yet.
+
+
 
 
 Payload part
 ------------------------
 
 Binary format is as follow
 
 :header size: (16 bits inter)
 
   The total number of Bytes used by the part headers. When the header is empty
   (size = 0) this is interpreted as the end of stream marker.
 
   Currently forced to 0 in the current state of the implementation
 """
 
 import util
+import struct
+
 import changegroup
 from i18n import _
 
+_pack = struct.pack
+_unpack = struct.unpack
+
 _magicstring = 'HG20'
 
+_fstreamparamsize = '>H'
+
 class bundle20(object):
     """represent an outgoing bundle2 container
 
-    People will eventually be able to add param and parts to this object and
-    generated a stream from it."""
+    Use the `addparam` method to add stream level parameter. Then call
+    `getchunks` to retrieve all the binary chunks of datathat compose the
+    bundle2 container.
+
+    This object does not support payload part yet."""
 
     def __init__(self):
         self._params = []
         self._parts = []
 
+    def addparam(self, name, value=None):
+        """add a stream level parameter"""
+        self._params.append((name, value))
+
     def getchunks(self):
         yield _magicstring
-        # no support for any param yet
-        # to be obviously fixed soon.
-        assert not self._params
-        yield '\0\0'
+        param = self._paramchunk()
+        yield _pack(_fstreamparamsize, len(param))
+        if param:
+            yield param
+
         # no support for parts
         # to be obviously fixed soon.
         assert not self._parts
         yield '\0\0'
 
+    def _paramchunk(self):
+        """return a encoded version of all stream parameters"""
+        blocks = []
+        for key, value in self._params:
+            # XXX no support for value yet
+            assert value is None
+            # XXX no escaping yet
+            blocks.append(key)
+        return ' '.join(blocks)
+
 class unbundle20(object):
     """interpret a bundle2 stream
 
     (this will eventually yield parts)"""
 
     def __init__(self, fp):
         self._fp = fp
         header = self._readexact(4)
         magic, version = header[0:2], header[2:4]
         if magic != 'HG':
             raise util.Abort(_('not a Mercurial bundle'))
         if version != '20':
             raise util.Abort(_('unknown bundle version %s') % version)
 
     def _unpack(self, format):
         """unpack this struct format from the stream"""
         data = self._readexact(struct.calcsize(format))
         return _unpack(format, data)
 
     def _readexact(self, size):
         """read exactly <size> bytes from the stream"""
         return changegroup.readexactly(self._fp, size)
 
     @util.propertycache
     def params(self):
         """dictionnary of stream level parameters"""
         paramsize = self._readexact(2)
         assert paramsize == '\0\0'
         return {}
 
     def __iter__(self):
         """yield all parts contained in the stream"""
         # make sure param have been loaded
         self.params
         part = self._readpart()
         while part is not None:
             yield part
             part = self._readpart()
 
     def _readpart(self):
         """return None when an end of stream markers is reach"""
         headersize = self._readexact(2)
         assert headersize == '\0\0'
         return None
 
 
 

tests/test-bundle2.t

@@ -1,62 +1,94
 
 Create an extension to test bundle2 API
 
   $ cat > bundle2.py << EOF
   > """A small extension to test bundle2 implementation
   > 
   > Current bundle2 implementation is far too limited to be used in any core
   > code. We still need to be able to test it while it grow up.
   > """
   > 
   > import sys
   > from mercurial import cmdutil
   > from mercurial import bundle2
   > cmdtable = {}
   > command = cmdutil.command(cmdtable)
   > 
-  > @command('bundle2', [], '')
-  > def cmdbundle2(ui, repo):
+  > @command('bundle2',
+  >          [('', 'param', [], 'stream level parameter'),],
+  >          '')
+  > def cmdbundle2(ui, repo, **opts):
   >     """write a bundle2 container on standard ouput"""
-  >     bundle = bundle2.bundle20()
-  >     for chunk in bundle.getchunks():
+  >     bundler = bundle2.bundle20()
+  >     for p in opts['param']:
+  >         bundler.addparam(p)
+  >     for chunk in bundler.getchunks():
   >         ui.write(chunk)
   > 
   > @command('unbundle2', [], '')
   > def cmdunbundle2(ui, repo):
   >     """read a bundle2 container from standard input"""
   >     unbundler = bundle2.unbundle20(sys.stdin)
   >     ui.write('options count: %i\n' % len(unbundler.params))
   >     parts = list(unbundler)
   >     ui.write('parts count:   %i\n' % len(parts))
   > EOF
   $ cat >> $HGRCPATH << EOF
   > [extensions]
   > bundle2=$TESTTMP/bundle2.py
   > EOF
 
 The extension requires a repo (currently unused)
 
   $ hg init main
   $ cd main
   $ touch a
   $ hg add a
   $ hg commit -m 'a'
 
-Test simple generation of empty bundle
+
+Empty bundle
+=================
+
+- no option
+- no parts
+
+Test bundling
 
   $ hg bundle2
   HG20\x00\x00\x00\x00 (no-eol) (esc)
 
-Test parsing of an empty bundle
+Test unbundling
 
   $ hg bundle2 | hg unbundle2
   options count: 0
   parts count:   0
 
 Test old style bundle are detected and refused
 
   $ hg bundle --all ../bundle.hg
   1 changesets found
   $ hg unbundle2 < ../bundle.hg
   abort: unknown bundle version 10
   [255]
+
+Test parameters
+=================
+
+- some options
+- no parts
+
+advisory parameters, no value
+-------------------------------
+
+Simplest possible parameters form
+
+Test generation
+
+  $ hg bundle2 --param 'caution'
+  HG20\x00\x07caution\x00\x00 (no-eol) (esc)
+
+Test generation multiple option
+
+  $ hg bundle2 --param 'caution' --param 'meal'
+  HG20\x00\x0ccaution meal\x00\x00 (no-eol) (esc)