dispatch: add pagination of two more help cases
I missed these in the last round anf Yuya spotted them in
review. Thanks!
# mpatch.py - Python implementation of mpatch.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
from . import policy, pycompat
stringio = pycompat.stringio
modulepolicy = policy.policy
policynocffi = policy.policynocffi
class mpatchError(Exception):
"""error raised when a delta cannot be decoded
"""
# This attempts to apply a series of patches in time proportional to
# the total size of the patches, rather than patches * len(text). This
# means rather than shuffling strings around, we shuffle around
# pointers to fragments with fragment lists.
#
# When the fragment lists get too long, we collapse them. To do this
# efficiently, we do all our operations inside a buffer created by
# mmap and simply use memmove. This avoids creating a bunch of large
# temporary string buffers.
def _pull(dst, src, l): # pull l bytes from src
while l:
f = src.pop()
if f[0] > l: # do we need to split?
src.append((f[0] - l, f[1] + l))
dst.append((l, f[1]))
return
dst.append(f)
l -= f[0]
def _move(m, dest, src, count):
"""move count bytes from src to dest
The file pointer is left at the end of dest.
"""
m.seek(src)
buf = m.read(count)
m.seek(dest)
m.write(buf)
def _collect(m, buf, list):
start = buf
for l, p in reversed(list):
_move(m, buf, p, l)
buf += l
return (buf - start, start)
def patches(a, bins):
if not bins:
return a
plens = [len(x) for x in bins]
pl = sum(plens)
bl = len(a) + pl
tl = bl + bl + pl # enough for the patches and two working texts
b1, b2 = 0, bl
if not tl:
return a
m = stringio()
# load our original text
m.write(a)
frags = [(len(a), b1)]
# copy all the patches into our segment so we can memmove from them
pos = b2 + bl
m.seek(pos)
for p in bins: m.write(p)
for plen in plens:
# if our list gets too long, execute it
if len(frags) > 128:
b2, b1 = b1, b2
frags = [_collect(m, b1, frags)]
new = []
end = pos + plen
last = 0
while pos < end:
m.seek(pos)
try:
p1, p2, l = struct.unpack(">lll", m.read(12))
except struct.error:
raise mpatchError("patch cannot be decoded")
_pull(new, frags, p1 - last) # what didn't change
_pull([], frags, p2 - p1) # what got deleted
new.append((l, pos + 12)) # what got added
pos += l + 12
last = p2
frags.extend(reversed(new)) # what was left at the end
t = _collect(m, b2, frags)
m.seek(t[1])
return m.read(t[0])
def patchedsize(orig, delta):
outlen, last, bin = 0, 0, 0
binend = len(delta)
data = 12
while data <= binend:
decode = delta[bin:bin + 12]
start, end, length = struct.unpack(">lll", decode)
if start > end:
break
bin = data + length
data = bin + 12
outlen += start - last
last = end
outlen += length
if bin != binend:
raise mpatchError("patch cannot be decoded")
outlen += orig - last
return outlen
if modulepolicy not in policynocffi:
try:
from _mpatch_cffi import ffi, lib
except ImportError:
if modulepolicy == 'cffi': # strict cffi import
raise
else:
@ffi.def_extern()
def cffi_get_next_item(arg, pos):
all, bins = ffi.from_handle(arg)
container = ffi.new("struct mpatch_flist*[1]")
to_pass = ffi.new("char[]", str(bins[pos]))
all.append(to_pass)
r = lib.mpatch_decode(to_pass, len(to_pass) - 1, container)
if r < 0:
return ffi.NULL
return container[0]
def patches(text, bins):
lgt = len(bins)
all = []
if not lgt:
return text
arg = (all, bins)
patch = lib.mpatch_fold(ffi.new_handle(arg),
lib.cffi_get_next_item, 0, lgt)
if not patch:
raise mpatchError("cannot decode chunk")
outlen = lib.mpatch_calcsize(len(text), patch)
if outlen < 0:
lib.mpatch_lfree(patch)
raise mpatchError("inconsistency detected")
buf = ffi.new("char[]", outlen)
if lib.mpatch_apply(buf, text, len(text), patch) < 0:
lib.mpatch_lfree(patch)
raise mpatchError("error applying patches")
res = ffi.buffer(buf, outlen)[:]
lib.mpatch_lfree(patch)
return res