upstream/mercurial-mirror Files · mercurial/cffi/mpatch.py

interfaces: introduce and use a protocol class for the `mpatch` module...

interfaces: introduce and use a protocol class for the `mpatch` module See for details when this was done for the `bdiff` module. Two things worth pointing out- 1) The `cffi` module "inherits" the `pure` implementation of `patchedsize()` because of its wildcard import. 2) It's odd that the `mpatchError` lives in both `pure` and `cext` modules. I initially thought to move the exception into the new class, and make the existing class name an alias to the class in the new location, but the exception is created in C code by the `cext` module, so that won't work. I don't think a protocol class is approriate, because there's nothing special about the class to distinguish from any other `Exception`. Fortunately, nobody is catching this exception in core, so we can kick the can down the road.

Matt Harbison - - Load All Authors

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      # mpatch.py - CFFI implementation of mpatch.c

      #

      # Copyright 2016 Maciej Fijalkowski <fijall@gmail.com>

      #

      # 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 annotations

      from typing import List

      from ..pure.mpatch import *

      from ..pure.mpatch import mpatchError  # silence pyflakes

      from . import _mpatch  # pytype: disable=import-error

      ffi = _mpatch.ffi

      lib = _mpatch.lib

      @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[]", bytes(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: bytes, bins: List[bytes]) -> bytes:

          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(b"cannot decode chunk")

          outlen = lib.mpatch_calcsize(len(text), patch)

          if outlen < 0:

              lib.mpatch_lfree(patch)

              raise mpatchError(b"inconsistency detected")

          buf = ffi.new("char[]", outlen)

          if lib.mpatch_apply(buf, text, len(text), patch) < 0:

              lib.mpatch_lfree(patch)

              raise mpatchError(b"error applying patches")

          res = ffi.buffer(buf, outlen)[:]

          lib.mpatch_lfree(patch)

          return res

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				# mpatch.py - CFFI implementation of mpatch.c
				#
				# Copyright 2016 Maciej Fijalkowski <fijall@gmail.com>
				#
				# 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 annotations

				from typing import List

				from ..pure.mpatch import *
				from ..pure.mpatch import mpatchError # silence pyflakes
				from . import _mpatch # pytype: disable=import-error

				ffi = _mpatch.ffi
				lib = _mpatch.lib


				@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[]", bytes(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: bytes, bins: List[bytes]) -> bytes:
				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(b"cannot decode chunk")
				outlen = lib.mpatch_calcsize(len(text), patch)
				if outlen < 0:
				lib.mpatch_lfree(patch)
				raise mpatchError(b"inconsistency detected")
				buf = ffi.new("char[]", outlen)
				if lib.mpatch_apply(buf, text, len(text), patch) < 0:
				lib.mpatch_lfree(patch)
				raise mpatchError(b"error applying patches")
				res = ffi.buffer(buf, outlen)[:]
				lib.mpatch_lfree(patch)
				return res