# shallowutil.py -- remotefilelog utilities

#

# Copyright 2014 Facebook, Inc.

#

# 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 collections

import errno

import hashlib

import os

import stat

import struct

import tempfile

from mercurial.i18n import _

from mercurial import (

    error,

    node,

    pycompat,

    revlog,

    util,

)

from mercurial.utils import (

    storageutil,

    stringutil,

)

from . import constants

if not pycompat.iswindows:

    import grp

def isenabled(repo):

    """returns whether the repository is remotefilelog enabled or not"""

    return constants.SHALLOWREPO_REQUIREMENT in repo.requirements

def getcachekey(reponame, file, id):

    pathhash = node.hex(hashlib.sha1(file).digest())

    return os.path.join(reponame, pathhash[:2], pathhash[2:], id)

def getlocalkey(file, id):

    pathhash = node.hex(hashlib.sha1(file).digest())

    return os.path.join(pathhash, id)

def getcachepath(ui, allowempty=False):

    cachepath = ui.config("remotefilelog", "cachepath")

    if not cachepath:

        if allowempty:

            return None

        else:

            raise error.Abort(_("could not find config option "

                                "remotefilelog.cachepath"))

    return util.expandpath(cachepath)

def getcachepackpath(repo, category):

    cachepath = getcachepath(repo.ui)

    if category != constants.FILEPACK_CATEGORY:

        return os.path.join(cachepath, repo.name, 'packs', category)

    else:

        return os.path.join(cachepath, repo.name, 'packs')

def getlocalpackpath(base, category):

    return os.path.join(base, 'packs', category)

def createrevlogtext(text, copyfrom=None, copyrev=None):

    """returns a string that matches the revlog contents in a

    traditional revlog

    """

    meta = {}

    if copyfrom or text.startswith('\1\n'):

        if copyfrom:

            meta['copy'] = copyfrom

            meta['copyrev'] = copyrev

        text = storageutil.packmeta(meta, text)

    return text

def parsemeta(text):

    """parse mercurial filelog metadata"""

    meta, size = storageutil.parsemeta(text)

    if text.startswith('\1\n'):

        s = text.index('\1\n', 2)

        text = text[s + 2:]

    return meta or {}, text

def sumdicts(*dicts):

    """Adds all the values of *dicts together into one dictionary. This assumes

    the values in *dicts are all summable.

    e.g. [{'a': 4', 'b': 2}, {'b': 3, 'c': 1}] -> {'a': 4, 'b': 5, 'c': 1}

    """

    result = collections.defaultdict(lambda: 0)

    for dict in dicts:

        for k, v in dict.iteritems():

            result[k] += v

    return result

def prefixkeys(dict, prefix):

    """Returns ``dict`` with ``prefix`` prepended to all its keys."""

    result = {}

    for k, v in dict.iteritems():

        result[prefix + k] = v

    return result

def reportpackmetrics(ui, prefix, *stores):

    dicts = [s.getmetrics() for s in stores]

    dict = prefixkeys(sumdicts(*dicts), prefix + '_')

    ui.log(prefix + "_packsizes", "\n", **pycompat.strkwargs(dict))

def _parsepackmeta(metabuf):

    """parse datapack meta, bytes (<metadata-list>) -> dict

    The dict contains raw content - both keys and values are strings.

    Upper-level business may want to convert some of them to other types like

    integers, on their own.

    raise ValueError if the data is corrupted

    """

    metadict = {}

    offset = 0

    buflen = len(metabuf)

    while buflen - offset >= 3:

        key = metabuf[offset:offset + 1]

        offset += 1

        metalen = struct.unpack_from('!H', metabuf, offset)[0]

        offset += 2

        if offset + metalen > buflen:

            raise ValueError('corrupted metadata: incomplete buffer')

        value = metabuf[offset:offset + metalen]

        metadict[key] = value

        offset += metalen

    if offset != buflen:

        raise ValueError('corrupted metadata: redundant data')

    return metadict

def _buildpackmeta(metadict):

    """reverse of _parsepackmeta, dict -> bytes (<metadata-list>)

    The dict contains raw content - both keys and values are strings.

    Upper-level business may want to serialize some of other types (like

    integers) to strings before calling this function.

    raise ProgrammingError when metadata key is illegal, or ValueError if

    length limit is exceeded

    """

    metabuf = ''

    for k, v in sorted((metadict or {}).iteritems()):

        if len(k) != 1:

            raise error.ProgrammingError('packmeta: illegal key: %s' % k)

        if len(v) > 0xfffe:

            raise ValueError('metadata value is too long: 0x%x > 0xfffe'

                             % len(v))

        metabuf += k

        metabuf += struct.pack('!H', len(v))

        metabuf += v

    # len(metabuf) is guaranteed representable in 4 bytes, because there are

    # only 256 keys, and for each value, len(value) <= 0xfffe.

    return metabuf

_metaitemtypes = {

    constants.METAKEYFLAG: (int, pycompat.long),

    constants.METAKEYSIZE: (int, pycompat.long),

}

def buildpackmeta(metadict):

    """like _buildpackmeta, but typechecks metadict and normalize it.

    This means, METAKEYSIZE and METAKEYSIZE should have integers as values,

    and METAKEYFLAG will be dropped if its value is 0.

    """

    newmeta = {}

    for k, v in (metadict or {}).iteritems():

        expectedtype = _metaitemtypes.get(k, (bytes,))

        if not isinstance(v, expectedtype):

            raise error.ProgrammingError('packmeta: wrong type of key %s' % k)

        # normalize int to binary buffer

        if int in expectedtype:

            # optimization: remove flag if it's 0 to save space

            if k == constants.METAKEYFLAG and v == 0:

                continue

            v = int2bin(v)

        newmeta[k] = v

    return _buildpackmeta(newmeta)

def parsepackmeta(metabuf):

    """like _parsepackmeta, but convert fields to desired types automatically.

    This means, METAKEYFLAG and METAKEYSIZE fields will be converted to

    integers.

    """

    metadict = _parsepackmeta(metabuf)

    for k, v in metadict.iteritems():

        if k in _metaitemtypes and int in _metaitemtypes[k]:

            metadict[k] = bin2int(v)

    return metadict

def int2bin(n):

    """convert a non-negative integer to raw binary buffer"""

    buf = bytearray()

    while n > 0:

        buf.insert(0, n & 0xff)

        n >>= 8

    return bytes(buf)

def bin2int(buf):

    """the reverse of int2bin, convert a binary buffer to an integer"""

    x = 0

    for b in bytearray(buf):

        x <<= 8

        x |= b

    return x

def parsesizeflags(raw):

    """given a remotefilelog blob, return (headersize, rawtextsize, flags)

    see remotefilelogserver.createfileblob for the format.

    raise RuntimeError if the content is illformed.

    """

    flags = revlog.REVIDX_DEFAULT_FLAGS

    size = None

    try:

        index = raw.index('\0')

        header = raw[:index]

        if header.startswith('v'):

            # v1 and above, header starts with 'v'

            if header.startswith('v1\n'):

                for s in header.split('\n'):

                    if s.startswith(constants.METAKEYSIZE):

                        size = int(s[len(constants.METAKEYSIZE):])

                    elif s.startswith(constants.METAKEYFLAG):

                        flags = int(s[len(constants.METAKEYFLAG):])

            else:

                raise RuntimeError('unsupported remotefilelog header: %s'

                                   % header)

        else:

            # v0, str(int(size)) is the header

            size = int(header)

    except ValueError:

        raise RuntimeError(r"unexpected remotefilelog header: illegal format")

    if size is None:

        raise RuntimeError(r"unexpected remotefilelog header: no size found")

    return index + 1, size, flags

def buildfileblobheader(size, flags, version=None):

    """return the header of a remotefilelog blob.

    see remotefilelogserver.createfileblob for the format.

    approximately the reverse of parsesizeflags.

    version could be 0 or 1, or None (auto decide).

    """

    # choose v0 if flags is empty, otherwise v1

    if version is None:

        version = int(bool(flags))

    if version == 1:

        header = ('v1\n%s%d\n%s%d'

                  % (constants.METAKEYSIZE, size,

                     constants.METAKEYFLAG, flags))

    elif version == 0:

        if flags:

            raise error.ProgrammingError('fileblob v0 does not support flag')

        header = '%d' % size

    else:

        raise error.ProgrammingError('unknown fileblob version %d' % version)

    return header

def ancestormap(raw):

    offset, size, flags = parsesizeflags(raw)

    start = offset + size

    mapping = {}

    while start < len(raw):

        divider = raw.index('\0', start + 80)

        currentnode = raw[start:(start + 20)]

        p1 = raw[(start + 20):(start + 40)]

        p2 = raw[(start + 40):(start + 60)]

        linknode = raw[(start + 60):(start + 80)]

        copyfrom = raw[(start + 80):divider]

        mapping[currentnode] = (p1, p2, linknode, copyfrom)

        start = divider + 1

    return mapping

def readfile(path):

    f = open(path, 'rb')

    try:

        result = f.read()

        # we should never have empty files

        if not result:

            os.remove(path)

            raise IOError("empty file: %s" % path)

        return result

    finally:

        f.close()

def unlinkfile(filepath):

    if pycompat.iswindows:

        # On Windows, os.unlink cannnot delete readonly files

        os.chmod(filepath, stat.S_IWUSR)

    os.unlink(filepath)

def renamefile(source, destination):

    if pycompat.iswindows:

        # On Windows, os.rename cannot rename readonly files

        # and cannot overwrite destination if it exists

        os.chmod(source, stat.S_IWUSR)

        if os.path.isfile(destination):

            os.chmod(destination, stat.S_IWUSR)

            os.unlink(destination)

    os.rename(source, destination)

def writefile(path, content, readonly=False):

    dirname, filename = os.path.split(path)

    if not os.path.exists(dirname):

        try:

            os.makedirs(dirname)

        except OSError as ex:

            if ex.errno != errno.EEXIST:

                raise

    fd, temp = tempfile.mkstemp(prefix='.%s-' % filename, dir=dirname)

    os.close(fd)

    try:

        f = util.posixfile(temp, 'wb')

        f.write(content)

        f.close()

        if readonly:

            mode = 0o444

        else:

            # tempfiles are created with 0o600, so we need to manually set the

            # mode.

            oldumask = os.umask(0)

            # there's no way to get the umask without modifying it, so set it

            # back

            os.umask(oldumask)

            mode = ~oldumask

        renamefile(temp, path)

        os.chmod(path, mode)

    except Exception:

        try:

            unlinkfile(temp)

        except OSError:

            pass

        raise

def sortnodes(nodes, parentfunc):

    """Topologically sorts the nodes, using the parentfunc to find

    the parents of nodes."""

    nodes = set(nodes)

    childmap = {}

    parentmap = {}

    roots = []

    # Build a child and parent map

    for n in nodes:

        parents = [p for p in parentfunc(n) if p in nodes]

        parentmap[n] = set(parents)

        for p in parents:

            childmap.setdefault(p, set()).add(n)

        if not parents:

            roots.append(n)

    roots.sort()

    # Process roots, adding children to the queue as they become roots

    results = []

    while roots:

        n = roots.pop(0)

        results.append(n)

        if n in childmap:

            children = childmap[n]

            for c in children:

                childparents = parentmap[c]

                childparents.remove(n)

                if len(childparents) == 0:

                    # insert at the beginning, that way child nodes

                    # are likely to be output immediately after their

                    # parents.  This gives better compression results.

                    roots.insert(0, c)

    return results

def readexactly(stream, n):

    '''read n bytes from stream.read and abort if less was available'''

    s = stream.read(n)

    if len(s) < n:

        raise error.Abort(_("stream ended unexpectedly"

                           " (got %d bytes, expected %d)")

                          % (len(s), n))

    return s

def readunpack(stream, fmt):

    data = readexactly(stream, struct.calcsize(fmt))

    return struct.unpack(fmt, data)

def readpath(stream):

    rawlen = readexactly(stream, constants.FILENAMESIZE)