wireprotov2: change command response protocol to include a leading map
The error handling mechanism for the new wire protocol isn't very
well-defined. This commit takes us a step in the right direction
by introducing a leading CBOR map for command responses. This map
will contain an overall result of the command.
Currently, the map indicates whether the command was overall
successful or if an error occurred. And if an error occurred, that
error is present in the map.
There is still a dedicated error frame. My intent is to use that
for protocol-level errors and for errors that are encountered after
the initial response frame has been sent. This will be clarified in a
later commit.
Differential Revision: https://phab.mercurial-scm.org/D3385
# parsers.py - Python implementation of parsers.c
#
# Copyright 2009 Matt Mackall <mpm@selenic.com> and others
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
from __future__ import absolute_import
import struct
import zlib
from ..node import nullid
from .. import pycompat
stringio = pycompat.bytesio
_pack = struct.pack
_unpack = struct.unpack
_compress = zlib.compress
_decompress = zlib.decompress
# Some code below makes tuples directly because it's more convenient. However,
# code outside this module should always use dirstatetuple.
def dirstatetuple(*x):
# x is a tuple
return x
indexformatng = ">Qiiiiii20s12x"
indexfirst = struct.calcsize('Q')
sizeint = struct.calcsize('i')
indexsize = struct.calcsize(indexformatng)
def gettype(q):
return int(q & 0xFFFF)
def offset_type(offset, type):
return int(int(offset) << 16 | type)
class BaseIndexObject(object):
def __len__(self):
return self._lgt + len(self._extra) + 1
def insert(self, i, tup):
assert i == -1
self._extra.append(tup)
def _fix_index(self, i):
if not isinstance(i, int):
raise TypeError("expecting int indexes")
if i < 0:
i = len(self) + i
if i < 0 or i >= len(self):
raise IndexError
return i
def __getitem__(self, i):
i = self._fix_index(i)
if i == len(self) - 1:
return (0, 0, 0, -1, -1, -1, -1, nullid)
if i >= self._lgt:
return self._extra[i - self._lgt]
index = self._calculate_index(i)
r = struct.unpack(indexformatng, self._data[index:index + indexsize])
if i == 0:
e = list(r)
type = gettype(e[0])
e[0] = offset_type(0, type)
return tuple(e)
return r
class IndexObject(BaseIndexObject):
def __init__(self, data):
assert len(data) % indexsize == 0
self._data = data
self._lgt = len(data) // indexsize
self._extra = []
def _calculate_index(self, i):
return i * indexsize
def __delitem__(self, i):
if not isinstance(i, slice) or not i.stop == -1 or i.step is not None:
raise ValueError("deleting slices only supports a:-1 with step 1")
i = self._fix_index(i.start)
if i < self._lgt:
self._data = self._data[:i * indexsize]
self._lgt = i
self._extra = []
else:
self._extra = self._extra[:i - self._lgt]
class InlinedIndexObject(BaseIndexObject):
def __init__(self, data, inline=0):
self._data = data
self._lgt = self._inline_scan(None)
self._inline_scan(self._lgt)
self._extra = []
def _inline_scan(self, lgt):
off = 0
if lgt is not None:
self._offsets = [0] * lgt
count = 0
while off <= len(self._data) - indexsize:
s, = struct.unpack('>i',
self._data[off + indexfirst:off + sizeint + indexfirst])
if lgt is not None:
self._offsets[count] = off
count += 1
off += indexsize + s
if off != len(self._data):
raise ValueError("corrupted data")
return count
def __delitem__(self, i):
if not isinstance(i, slice) or not i.stop == -1 or i.step is not None:
raise ValueError("deleting slices only supports a:-1 with step 1")
i = self._fix_index(i.start)
if i < self._lgt:
self._offsets = self._offsets[:i]
self._lgt = i
self._extra = []
else:
self._extra = self._extra[:i - self._lgt]
def _calculate_index(self, i):
return self._offsets[i]
def parse_index2(data, inline):
if not inline:
return IndexObject(data), None
return InlinedIndexObject(data, inline), (0, data)
def parse_dirstate(dmap, copymap, st):
parents = [st[:20], st[20: 40]]
# dereference fields so they will be local in loop
format = ">cllll"
e_size = struct.calcsize(format)
pos1 = 40
l = len(st)
# the inner loop
while pos1 < l:
pos2 = pos1 + e_size
e = _unpack(">cllll", st[pos1:pos2]) # a literal here is faster
pos1 = pos2 + e[4]
f = st[pos2:pos1]
if '\0' in f:
f, c = f.split('\0')
copymap[f] = c
dmap[f] = e[:4]
return parents
def pack_dirstate(dmap, copymap, pl, now):
now = int(now)
cs = stringio()
write = cs.write
write("".join(pl))
for f, e in dmap.iteritems():
if e[0] == 'n' and e[3] == now:
# The file was last modified "simultaneously" with the current
# write to dirstate (i.e. within the same second for file-
# systems with a granularity of 1 sec). This commonly happens
# for at least a couple of files on 'update'.
# The user could change the file without changing its size
# within the same second. Invalidate the file's mtime in
# dirstate, forcing future 'status' calls to compare the
# contents of the file if the size is the same. This prevents
# mistakenly treating such files as clean.
e = dirstatetuple(e[0], e[1], e[2], -1)
dmap[f] = e
if f in copymap:
f = "%s\0%s" % (f, copymap[f])
e = _pack(">cllll", e[0], e[1], e[2], e[3], len(f))
write(e)
write(f)
return cs.getvalue()