[PATCH v4] lazymanifest: write a more efficient, pypy friendly version of lazymanifest

Augie Fackler raf at durin42.com
Sun Oct 2 22:09:34 EDT 2016


I’ve tentatively queued this, tests are running now. I have to go to bed now, so I’ll report the final verdict in the morning (don’t have easy access to a fast machine with pypy right now, so I’m just running it (slowly) on a Mac laptop.)

> On Oct 1, 2016, at 4:38 AM, Maciej Fijalkowski <fijall at gmail.com> wrote:
> 
> # HG changeset patch
> # User Maciej Fijalkowski <fijall at gmail.com>
> # Date 1473680234 -7200
> #      Mon Sep 12 13:37:14 2016 +0200
> # Node ID c770219dc4c253d7cd82519ce3c74438bb2829d3
> # Parent  df05c43bd1e64f1620d0b2e502f4603c1e5a8341
> lazymanifest: write a more efficient, pypy friendly version of lazymanifest
> 
> diff --git a/mercurial/manifest.py b/mercurial/manifest.py
> --- a/mercurial/manifest.py
> +++ b/mercurial/manifest.py
> @@ -104,69 +104,300 @@
>     _checkforbidden(files)
>     return ''.join(lines)
> 
> -class _lazymanifest(dict):
> -    """This is the pure implementation of lazymanifest.
> -
> -    It has not been optimized *at all* and is not lazy.
> -    """
> -
> -    def __init__(self, data):
> -        dict.__init__(self)
> -        for f, n, fl in _parse(data):
> -            self[f] = n, fl
> -
> -    def __setitem__(self, k, v):
> -        node, flag = v
> -        assert node is not None
> -        if len(node) > 21:
> -            node = node[:21] # match c implementation behavior
> -        dict.__setitem__(self, k, (node, flag))
> +class lazymanifestiter(object):
> +    def __init__(self, lm):
> +        self.pos = 0
> +        self.lm = lm
> 
>     def __iter__(self):
> -        return iter(sorted(dict.keys(self)))
> +        return self
> 
> -    def iterkeys(self):
> -        return iter(sorted(dict.keys(self)))
> +    def next(self):
> +        try:
> +            data, pos = self.lm._get(self.pos)
> +        except IndexError:
> +            raise StopIteration
> +        if pos == -1:
> +            self.pos += 1
> +            return data[0]
> +        self.pos += 1
> +        zeropos = data.find('\x00', pos)
> +        return data[pos:zeropos]
> 
> -    def iterentries(self):
> -        return ((f, e[0], e[1]) for f, e in sorted(self.iteritems()))
> +class lazymanifestiterentries(object):
> +    def __init__(self, lm):
> +        self.lm = lm
> +        self.pos = 0
> +
> +    def __iter__(self):
> +        return self
> +
> +    def next(self):
> +        try:
> +            data, pos = self.lm._get(self.pos)
> +        except IndexError:
> +            raise StopIteration
> +        if pos == -1:
> +            self.pos += 1
> +            return data
> +        zeropos = data.find('\x00', pos)
> +        hashval = unhexlify(data, self.lm.extrainfo[self.pos],
> +                            zeropos + 1, 40)
> +        flags = self.lm._getflags(data, self.pos, zeropos)
> +        self.pos += 1
> +        return (data[pos:zeropos], hashval, flags)
> +
> +def unhexlify(data, extra, pos, length):
> +    s = data[pos:pos + length].decode('hex')
> +    if extra:
> +        s += chr(extra & 0xff)
> +    return s
> +
> +def _cmp(a, b):
> +    return (a > b) - (a < b)
> +
> +class _lazymanifest(object):
> +    def __init__(self, data, positions=None, extrainfo=None, extradata=None):
> +        if positions is None:
> +            self.positions = self.findlines(data)
> +            self.extrainfo = [0] * len(self.positions)
> +            self.data = data
> +            self.extradata = []
> +        else:
> +            self.positions = positions[:]
> +            self.extrainfo = extrainfo[:]
> +            self.extradata = extradata[:]
> +            self.data = data
> +
> +    def findlines(self, data):
> +        if not data:
> +            return []
> +        pos = data.find("\n")
> +        if pos == -1 or data[-1] != '\n':
> +            raise ValueError("Manifest did not end in a newline.")
> +        positions = [0]
> +        prev = data[:data.find('\x00')]
> +        while pos < len(data) - 1 and pos != -1:
> +            positions.append(pos + 1)
> +            nexts = data[pos + 1:data.find('\x00', pos + 1)]
> +            if nexts < prev:
> +                raise ValueError("Manifest lines not in sorted order.")
> +            prev = nexts
> +            pos = data.find("\n", pos + 1)
> +        return positions
> +
> +    def _get(self, index):
> +        # get the position encoded in pos:
> +        #   positive number is an index in 'data'
> +        #   negative number is in extrapieces
> +        pos = self.positions[index]
> +        if pos >= 0:
> +            return self.data, pos
> +        return self.extradata[-pos - 1], -1
> +
> +    def _getkey(self, pos):
> +        if pos >= 0:
> +            return self.data[pos:self.data.find('\x00', pos + 1)]
> +        return self.extradata[-pos - 1][0]
> +
> +    def bsearch(self, key):
> +        first = 0
> +        last = len(self.positions) - 1
> +
> +        while first <= last:
> +            midpoint = (first + last)//2
> +            nextpos = self.positions[midpoint]
> +            candidate = self._getkey(nextpos)
> +            r = _cmp(key, candidate)
> +            if r == 0:
> +                return midpoint
> +            else:
> +                if r < 0:
> +                    last = midpoint - 1
> +                else:
> +                    first = midpoint + 1
> +        return -1
> +
> +    def bsearch2(self, key):
> +        # same as the above, but will always return the position
> +        # done for performance reasons
> +        first = 0
> +        last = len(self.positions) - 1
> +
> +        while first <= last:
> +            midpoint = (first + last)//2
> +            nextpos = self.positions[midpoint]
> +            candidate = self._getkey(nextpos)
> +            r = _cmp(key, candidate)
> +            if r == 0:
> +                return (midpoint, True)
> +            else:
> +                if r < 0:
> +                    last = midpoint - 1
> +                else:
> +                    first = midpoint + 1
> +        return (first, False)
> +
> +    def __contains__(self, key):
> +        return self.bsearch(key) != -1
> +
> +    def _getflags(self, data, needle, pos):
> +        start = pos + 41
> +        end = data.find("\n", start)
> +        if end == -1:
> +            end = len(data) - 1
> +        if start == end:
> +            return ''
> +        return self.data[start:end]
> +
> +    def __getitem__(self, key):
> +        if not isinstance(key, str):
> +            raise TypeError("getitem: manifest keys must be a string.")
> +        needle = self.bsearch(key)
> +        if needle == -1:
> +            raise KeyError
> +        data, pos = self._get(needle)
> +        if pos == -1:
> +            return (data[1], data[2])
> +        zeropos = data.find('\x00', pos)
> +        assert 0 <= needle <= len(self.positions)
> +        assert len(self.extrainfo) == len(self.positions)
> +        hashval = unhexlify(data, self.extrainfo[needle], zeropos + 1, 40)
> +        flags = self._getflags(data, needle, zeropos)
> +        return (hashval, flags)
> +
> +    def __delitem__(self, key):
> +        needle, found = self.bsearch2(key)
> +        if not found:
> +            raise KeyError
> +        cur = self.positions[needle]
> +        self.positions = self.positions[:needle] + self.positions[needle + 1:]
> +        self.extrainfo = self.extrainfo[:needle] + self.extrainfo[needle + 1:]
> +        if cur >= 0:
> +            self.data = self.data[:cur] + '\x00' + self.data[cur + 1:]
> +
> +    def __setitem__(self, key, value):
> +        if not isinstance(key, str):
> +            raise TypeError("setitem: manifest keys must be a string.")
> +        if not isinstance(value, tuple) or len(value) != 2:
> +            raise TypeError("Manifest values must be a tuple of (node, flags).")
> +        hashval = value[0]
> +        if not isinstance(hashval, str) or not 20 <= len(hashval) <= 22:
> +            raise TypeError("node must be a 20-byte string")
> +        flags = value[1]
> +        if len(hashval) == 22:
> +            hashval = hashval[:-1]
> +        if not isinstance(flags, str) or len(flags) > 1:
> +            raise TypeError("flags must a 0 or 1 byte string, got %r", flags)
> +        needle, found = self.bsearch2(key)
> +        if found:
> +            # put the item
> +            pos = self.positions[needle]
> +            if pos < 0:
> +                self.extradata[-pos - 1] = (key, hashval, value[1])
> +            else:
> +                # just don't bother
> +                self.extradata.append((key, hashval, value[1]))
> +                self.positions[needle] = -len(self.extradata)
> +        else:
> +            # not found, put it in with extra positions
> +            self.extradata.append((key, hashval, value[1]))
> +            self.positions = (self.positions[:needle] + [-len(self.extradata)]
> +                              + self.positions[needle:])
> +            self.extrainfo = (self.extrainfo[:needle] + [0] +
> +                              self.extrainfo[needle:])
> 
>     def copy(self):
> -        c = _lazymanifest('')
> -        c.update(self)
> -        return c
> +        # XXX call _compact like in C?
> +        return _lazymanifest(self.data, self.positions, self.extrainfo,
> +            self.extradata)
> +
> +    def _compact(self):
> +        # hopefully not called TOO often
> +        if len(self.extradata) == 0:
> +            return
> +        l = []
> +        last_cut = 0
> +        i = 0
> +        offset = 0
> +        self.extrainfo = [0] * len(self.positions)
> +        while i < len(self.positions):
> +            if self.positions[i] >= 0:
> +                cur = self.positions[i]
> +                last_cut = cur
> +                while True:
> +                    self.positions[i] = offset
> +                    i += 1
> +                    if i == len(self.positions) or self.positions[i] < 0:
> +                        break
> +                    offset += self.positions[i] - cur
> +                    cur = self.positions[i]
> +                end_cut = self.data.find('\n', cur)
> +                if end_cut != -1:
> +                    end_cut += 1
> +                offset += end_cut - cur
> +                l.append(self.data[last_cut:end_cut])
> +            else:
> +                while i < len(self.positions) and self.positions[i] < 0:
> +                    cur = self.positions[i]
> +                    t = self.extradata[-cur - 1]
> +                    l.append(self._pack(t))
> +                    self.positions[i] = offset
> +                    if len(t[1]) > 20:
> +                        self.extrainfo[i] = ord(t[1][21])
> +                    offset += len(l[-1])
> +                    i += 1
> +        self.data = ''.join(l)
> +        self.extradata = []
> +
> +    def _pack(self, d):
> +        return d[0] + '\x00' + d[1][:20].encode('hex') + d[2] + '\n'
> +
> +    def text(self):
> +        self._compact()
> +        return self.data
> 
>     def diff(self, m2, clean=False):
>         '''Finds changes between the current manifest and m2.'''
> +        # XXX think whether efficiency matters here
>         diff = {}
> 
> -        for fn, e1 in self.iteritems():
> +        for fn, e1, flags in self.iterentries():
>             if fn not in m2:
> -                diff[fn] = e1, (None, '')
> +                diff[fn] = (e1, flags), (None, '')
>             else:
>                 e2 = m2[fn]
> -                if e1 != e2:
> -                    diff[fn] = e1, e2
> +                if (e1, flags) != e2:
> +                    diff[fn] = (e1, flags), e2
>                 elif clean:
>                     diff[fn] = None
> 
> -        for fn, e2 in m2.iteritems():
> +        for fn, e2, flags in m2.iterentries():
>             if fn not in self:
> -                diff[fn] = (None, ''), e2
> +                diff[fn] = (None, ''), (e2, flags)
> 
>         return diff
> 
> +    def iterentries(self):
> +        return lazymanifestiterentries(self)
> +
> +    def iterkeys(self):
> +        return lazymanifestiter(self)
> +
> +    def __iter__(self):
> +        return lazymanifestiter(self)
> +
> +    def __len__(self):
> +        return len(self.positions)
> +
>     def filtercopy(self, filterfn):
> +        # XXX should be optimized
>         c = _lazymanifest('')
>         for f, n, fl in self.iterentries():
>             if filterfn(f):
>                 c[f] = n, fl
>         return c
> 
> -    def text(self):
> -        """Get the full data of this manifest as a bytestring."""
> -        return _textv1(self.iterentries())
> -
> try:
>     _lazymanifest = parsers.lazymanifest
> except AttributeError:
> diff --git a/mercurial/pure/bdiff.py b/mercurial/pure/bdiff.py
> --- a/mercurial/pure/bdiff.py
> +++ b/mercurial/pure/bdiff.py
> @@ -111,8 +111,8 @@
>         def blocks(sa, sb):
>             a = ffi.new("struct bdiff_line**")
>             b = ffi.new("struct bdiff_line**")
> -            ac = ffi.new("char[]", sa)
> -            bc = ffi.new("char[]", sb)
> +            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)
> @@ -138,8 +138,8 @@
>         def bdiff(sa, sb):
>             a = ffi.new("struct bdiff_line**")
>             b = ffi.new("struct bdiff_line**")
> -            ac = ffi.new("char[]", sa)
> -            bc = ffi.new("char[]", sb)
> +            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)
> _______________________________________________
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