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

revlog: add the option to track the expected compression upper bound...

revlog: add the option to track the expected compression upper bound There are various optimization we can do if we can estimate the size of delta before actually spending CPU compressing them. So we add a attributed dedicated to tracking that. We only use it on Manifest because (1) it structure is quite stable across all Mercurial repository so its compression ratio is fairly universal. This is the revlog with most extreme delta (cf the sparse-revlog optimization). This will be put to use in later changesets. Right now the compression upper bound is set to 10. This is a fairly conservative value (observed value is more around 3), but I prefer to be safe while introducing the optimization principles. We can tune the optimization threshold later.

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        Yuya Nishihara
    
cffi: split modules from pure...

              r32512
            
      # bdiff.py - CFFI implementation of bdiff.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 absolute_import

      import struct

      from ..pure.bdiff import *

      from . import _bdiff

      ffi = _bdiff.ffi

      lib = _bdiff.lib

        Yuya Nishihara
    
cffi: remove superfluous "if True" blocks

              r32513
            
      def blocks(sa, sb):

          a = ffi.new("struct bdiff_line**")

          b = ffi.new("struct bdiff_line**")

          ac = ffi.new("char[]", str(sa))

          bc = ffi.new("char[]", str(sb))

          l = ffi.new("struct bdiff_hunk*")

          try:

              an = lib.bdiff_splitlines(ac, len(sa), a)

              bn = lib.bdiff_splitlines(bc, len(sb), b)

              if not a[0] or not b[0]:

                  raise MemoryError

              count = lib.bdiff_diff(a[0], an, b[0], bn, l)

              if count < 0:

                  raise MemoryError

              rl = [None] * count

              h = l.next

              i = 0

              while h:

                  rl[i] = (h.a1, h.a2, h.b1, h.b2)

                  h = h.next

                  i += 1

          finally:

              lib.free(a[0])

              lib.free(b[0])

              lib.bdiff_freehunks(l.next)

          return rl

        Yuya Nishihara
    
cffi: split modules from pure...

              r32512
            
        Yuya Nishihara
    
cffi: remove superfluous "if True" blocks

              r32513
            
      def bdiff(sa, sb):

          a = ffi.new("struct bdiff_line**")

          b = ffi.new("struct bdiff_line**")

          ac = ffi.new("char[]", str(sa))

          bc = ffi.new("char[]", str(sb))

          l = ffi.new("struct bdiff_hunk*")

          try:

              an = lib.bdiff_splitlines(ac, len(sa), a)

              bn = lib.bdiff_splitlines(bc, len(sb), b)

              if not a[0] or not b[0]:

                  raise MemoryError

              count = lib.bdiff_diff(a[0], an, b[0], bn, l)

              if count < 0:

                  raise MemoryError

              rl = []

              h = l.next

              la = lb = 0

              while h:

                  if h.a1 != la or h.b1 != lb:

                      lgt = (b[0] + h.b1).l - (b[0] + lb).l

                      rl.append(struct.pack(">lll", (a[0] + la).l - a[0].l,

                                            (a[0] + h.a1).l - a[0].l, lgt))

                      rl.append(str(ffi.buffer((b[0] + lb).l, lgt)))

                  la = h.a2

                  lb = h.b2

                  h = h.next

        Yuya Nishihara
    
cffi: split modules from pure...

              r32512
            
        Yuya Nishihara
    
cffi: remove superfluous "if True" blocks

              r32513
            
          finally:

              lib.free(a[0])

              lib.free(b[0])

              lib.bdiff_freehunks(l.next)

          return "".join(rl)

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Yuya Nishihara cffi: split modules from pure...	r32512	# bdiff.py - CFFI implementation of bdiff.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 absolute_import

		import struct

		from ..pure.bdiff import *
		from . import _bdiff

		ffi = _bdiff.ffi
		lib = _bdiff.lib

Yuya Nishihara cffi: remove superfluous "if True" blocks	r32513	def blocks(sa, sb):
		a = ffi.new("struct bdiff_line**")
		b = ffi.new("struct bdiff_line**")
		ac = ffi.new("char[]", str(sa))
		bc = ffi.new("char[]", str(sb))
		l = ffi.new("struct bdiff_hunk*")
		try:
		an = lib.bdiff_splitlines(ac, len(sa), a)
		bn = lib.bdiff_splitlines(bc, len(sb), b)
		if not a[0] or not b[0]:
		raise MemoryError
		count = lib.bdiff_diff(a[0], an, b[0], bn, l)
		if count < 0:
		raise MemoryError
		rl = [None] * count
		h = l.next
		i = 0
		while h:
		rl[i] = (h.a1, h.a2, h.b1, h.b2)
		h = h.next
		i += 1
		finally:
		lib.free(a[0])
		lib.free(b[0])
		lib.bdiff_freehunks(l.next)
		return rl
Yuya Nishihara cffi: split modules from pure...	r32512
Yuya Nishihara cffi: remove superfluous "if True" blocks	r32513	def bdiff(sa, sb):
		a = ffi.new("struct bdiff_line**")
		b = ffi.new("struct bdiff_line**")
		ac = ffi.new("char[]", str(sa))
		bc = ffi.new("char[]", str(sb))
		l = ffi.new("struct bdiff_hunk*")
		try:
		an = lib.bdiff_splitlines(ac, len(sa), a)
		bn = lib.bdiff_splitlines(bc, len(sb), b)
		if not a[0] or not b[0]:
		raise MemoryError
		count = lib.bdiff_diff(a[0], an, b[0], bn, l)
		if count < 0:
		raise MemoryError
		rl = []
		h = l.next
		la = lb = 0
		while h:
		if h.a1 != la or h.b1 != lb:
		lgt = (b[0] + h.b1).l - (b[0] + lb).l
		rl.append(struct.pack(">lll", (a[0] + la).l - a[0].l,
		(a[0] + h.a1).l - a[0].l, lgt))
		rl.append(str(ffi.buffer((b[0] + lb).l, lgt)))
		la = h.a2
		lb = h.b2
		h = h.next
Yuya Nishihara cffi: split modules from pure...	r32512
Yuya Nishihara cffi: remove superfluous "if True" blocks	r32513	finally:
		lib.free(a[0])
		lib.free(b[0])
		lib.bdiff_freehunks(l.next)
		return "".join(rl)