text: # bundlecaches.py - utility to deal with pre-computed bundle for servers
  #
  # This software may be used and distributed according to the terms of the
  # GNU General Public License version 2 or any later version.
  
  from .i18n import _
  
  from .thirdparty import attr
  
  from . import (
      error,
      sslutil,
      util,
  )
  from .utils import stringutil
  
  urlreq = util.urlreq
  
  CB_MANIFEST_FILE = b'clonebundles.manifest'
  
  
  @attr.s
  class bundlespec(object):
      compression = attr.ib()
      wirecompression = attr.ib()
      version = attr.ib()
      wireversion = attr.ib()
      params = attr.ib()
      contentopts = attr.ib()
  
  
  # Maps bundle version human names to changegroup versions.
  _bundlespeccgversions = {
      b'v1': b'01',
      b'v2': b'02',
      b'packed1': b's1',
      b'bundle2': b'02',  # legacy
  }
  
  # Maps bundle version with content opts to choose which part to bundle
  _bundlespeccontentopts = {
      b'v1': {
          b'changegroup': True,
          b'cg.version': b'01',
          b'obsolescence': False,
          b'phases': False,
          b'tagsfnodescache': False,
          b'revbranchcache': False,
      },
      b'v2': {
          b'changegroup': True,
          b'cg.version': b'02',
          b'obsolescence': False,
          b'phases': False,
          b'tagsfnodescache': True,
          b'revbranchcache': True,
      },
      b'packed1': {b'cg.version': b's1'},
  }
  _bundlespeccontentopts[b'bundle2'] = _bundlespeccontentopts[b'v2']
  
  _bundlespecvariants = {
      b"streamv2": {
          b"changegroup": False,
          b"streamv2": True,
          b"tagsfnodescache": False,
          b"revbranchcache": False,
      }
  }
  
  # Compression engines allowed in version 1. THIS SHOULD NEVER CHANGE.
  _bundlespecv1compengines = {b'gzip', b'bzip2', b'none'}
  
  
  def parsebundlespec(repo, spec, strict=True):
      """Parse a bundle string specification into parts.
  
      Bundle specifications denote a well-defined bundle/exchange format.
      The content of a given specification should not change over time in
      order to ensure that bundles produced by a newer version of Mercurial are
      readable from an older version.
  
      The string currently has the form:
  
         <compression>-<type>[;<parameter0>[;<parameter1>]]
  
      Where <compression> is one of the supported compression formats
      and <type> is (currently) a version string. A ";" can follow the type and
      all text afterwards is interpreted as URI encoded, ";" delimited key=value
      pairs.
  
      If ``strict`` is True (the default) <compression> is required. Otherwise,
      it is optional.
  
      Returns a bundlespec object of (compression, version, parameters).
      Compression will be ``None`` if not in strict mode and a compression isn't
      defined.
  
      An ``InvalidBundleSpecification`` is raised when the specification is
      not syntactically well formed.
  
      An ``UnsupportedBundleSpecification`` is raised when the compression or
      bundle type/version is not recognized.
  
      Note: this function will likely eventually return a more complex data
      structure, including bundle2 part information.
      """
  
      def parseparams(s):
          if b';' not in s:
              return s, {}
  
          params = {}
          version, paramstr = s.split(b';', 1)
  
          for p in paramstr.split(b';'):
              if b'=' not in p:
                  raise error.InvalidBundleSpecification(
                      _(
                          b'invalid bundle specification: '
                          b'missing "=" in parameter: %s'
                      )
                      % p
                  )
  
              key, value = p.split(b'=', 1)
              key = urlreq.unquote(key)
              value = urlreq.unquote(value)
              params[key] = value
  
          return version, params
  
      if strict and b'-' not in spec:
          raise error.InvalidBundleSpecification(
              _(
                  b'invalid bundle specification; '
                  b'must be prefixed with compression: %s'
              )
              % spec
          )
  
      if b'-' in spec:
          compression, version = spec.split(b'-', 1)
  
          if compression not in util.compengines.supportedbundlenames:
              raise error.UnsupportedBundleSpecification(
                  _(b'%s compression is not supported') % compression
              )
  
          version, params = parseparams(version)
  
          if version not in _bundlespeccgversions:
              raise error.UnsupportedBundleSpecification(
                  _(b'%s is not a recognized bundle version') % version
              )
      else:
          # Value could be just the compression or just the version, in which
          # case some defaults are assumed (but only when not in strict mode).
          assert not strict
  
          spec, params = parseparams(spec)
  
          if spec in util.compengines.supportedbundlenames:
              compression = spec
              version = b'v1'
              # Generaldelta repos require v2.
              if b'generaldelta' in repo.requirements:
                  version = b'v2'
              # Modern compression engines require v2.
              if compression not in _bundlespecv1compengines:
                  version = b'v2'
          elif spec in _bundlespeccgversions:
              if spec == b'packed1':
                  compression = b'none'
              else:
                  compression = b'bzip2'
              version = spec
          else:
              raise error.UnsupportedBundleSpecification(
                  _(b'%s is not a recognized bundle specification') % spec
              )
  
      # Bundle version 1 only supports a known set of compression engines.
      if version == b'v1' and compression not in _bundlespecv1compengines:
          raise error.UnsupportedBundleSpecification(
              _(b'compression engine %s is not supported on v1 bundles')
              % compression
          )
  
      # The specification for packed1 can optionally declare the data formats
      # required to apply it. If we see this metadata, compare against what the
      # repo supports and error if the bundle isn't compatible.
      if version == b'packed1' and b'requirements' in params:
          requirements = set(params[b'requirements'].split(b','))
          missingreqs = requirements - repo.supportedformats
          if missingreqs:
              raise error.UnsupportedBundleSpecification(
                  _(b'missing support for repository features: %s')
                  % b', '.join(sorted(missingreqs))
              )
  
      # Compute contentopts based on the version
      contentopts = _bundlespeccontentopts.get(version, {}).copy()
  
      # Process the variants
      if b"stream" in params and params[b"stream"] == b"v2":
          variant = _bundlespecvariants[b"streamv2"]
          contentopts.update(variant)
  
      engine = util.compengines.forbundlename(compression)
      compression, wirecompression = engine.bundletype()
      wireversion = _bundlespeccgversions[version]
  
      return bundlespec(
          compression, wirecompression, version, wireversion, params, contentopts
      )
  
  
  def parseclonebundlesmanifest(repo, s):
      """Parses the raw text of a clone bundles manifest.
  
      Returns a list of dicts. The dicts have a ``URL`` key corresponding
      to the URL and other keys are the attributes for the entry.
      """
      m = []
      for line in s.splitlines():
          fields = line.split()
          if not fields:
              continue
          attrs = {b'URL': fields[0]}
          for rawattr in fields[1:]:
              key, value = rawattr.split(b'=', 1)
              key = util.urlreq.unquote(key)
              value = util.urlreq.unquote(value)
              attrs[key] = value
  
              # Parse BUNDLESPEC into components. This makes client-side
              # preferences easier to specify since you can prefer a single
              # component of the BUNDLESPEC.
              if key == b'BUNDLESPEC':
                  try:
                      bundlespec = parsebundlespec(repo, value)
                      attrs[b'COMPRESSION'] = bundlespec.compression
                      attrs[b'VERSION'] = bundlespec.version
                  except error.InvalidBundleSpecification:
                      pass
                  except error.UnsupportedBundleSpecification:
                      pass
  
          m.append(attrs)
  
      return m
  
  
  def isstreamclonespec(bundlespec):
      # Stream clone v1
      if bundlespec.wirecompression == b'UN' and bundlespec.wireversion == b's1':
          return True
  
      # Stream clone v2
      if (
          bundlespec.wirecompression == b'UN'
          and bundlespec.wireversion == b'02'
          and bundlespec.contentopts.get(b'streamv2')
      ):
          return True
  
      return False
  
  
  def filterclonebundleentries(repo, entries, streamclonerequested=False):
      """Remove incompatible clone bundle manifest entries.
  
      Accepts a list of entries parsed with ``parseclonebundlesmanifest``
      and returns a new list consisting of only the entries that this client
      should be able to apply.
  
      There is no guarantee we'll be able to apply all returned entries because
      the metadata we use to filter on may be missing or wrong.
      """
      newentries = []
      for entry in entries:
          spec = entry.get(b'BUNDLESPEC')
          if spec:
              try:
                  bundlespec = parsebundlespec(repo, spec, strict=True)
  
                  # If a stream clone was requested, filter out non-streamclone
                  # entries.
                  if streamclonerequested and not isstreamclonespec(bundlespec):
                      repo.ui.debug(
                          b'filtering %s because not a stream clone\n'
                          % entry[b'URL']
                      )
                      continue
  
              except error.InvalidBundleSpecification as e:
                  repo.ui.debug(stringutil.forcebytestr(e) + b'\n')
                  continue
              except error.UnsupportedBundleSpecification as e:
                  repo.ui.debug(
                      b'filtering %s because unsupported bundle '
                      b'spec: %s\n' % (entry[b'URL'], stringutil.forcebytestr(e))
                  )
                  continue
          # If we don't have a spec and requested a stream clone, we don't know
          # what the entry is so don't attempt to apply it.
          elif streamclonerequested:
              repo.ui.debug(
                  b'filtering %s because cannot determine if a stream '
                  b'clone bundle\n' % entry[b'URL']
              )
              continue
  
          if b'REQUIRESNI' in entry and not sslutil.hassni:
              repo.ui.debug(
                  b'filtering %s because SNI not supported\n' % entry[b'URL']
              )
              continue
  
          if b'REQUIREDRAM' in entry:
              try:
                  requiredram = util.sizetoint(entry[b'REQUIREDRAM'])
              except error.ParseError:
                  repo.ui.debug(
                      b'filtering %s due to a bad REQUIREDRAM attribute\n'
                      % entry[b'URL']
                  )
                  continue
              actualram = repo.ui.estimatememory()
              if actualram is not None and actualram * 0.66 < requiredram:
                  repo.ui.debug(
                      b'filtering %s as it needs more than 2/3 of system memory\n'
                      % entry[b'URL']
                  )
                  continue
  
          newentries.append(entry)
  
      return newentries
  
  
  class clonebundleentry(object):
      """Represents an item in a clone bundles manifest.
  
      This rich class is needed to support sorting since sorted() in Python 3
      doesn't support ``cmp`` and our comparison is complex enough that ``key=``
      won't work.
      """
  
      def __init__(self, value, prefers):
          self.value = value
          self.prefers = prefers
  
      def _cmp(self, other):
          for prefkey, prefvalue in self.prefers:
              avalue = self.value.get(prefkey)
              bvalue = other.value.get(prefkey)
  
              # Special case for b missing attribute and a matches exactly.
              if avalue is not None and bvalue is None and avalue == prefvalue:
                  return -1
  
              # Special case for a missing attribute and b matches exactly.
              if bvalue is not None and avalue is None and bvalue == prefvalue:
                  return 1
  
              # We can't compare unless attribute present on both.
              if avalue is None or bvalue is None:
                  continue
  
              # Same values should fall back to next attribute.
              if avalue == bvalue:
                  continue
  
              # Exact matches come first.
              if avalue == prefvalue:
                  return -1
              if bvalue == prefvalue:
                  return 1
  
              # Fall back to next attribute.
              continue
  
          # If we got here we couldn't sort by attributes and prefers. Fall
          # back to index order.
          return 0
  
      def __lt__(self, other):
          return self._cmp(other) < 0
  
      def __gt__(self, other):
          return self._cmp(other) > 0
  
      def __eq__(self, other):
          return self._cmp(other) == 0
  
      def __le__(self, other):
          return self._cmp(other) <= 0
  
      def __ge__(self, other):
          return self._cmp(other) >= 0
  
      def __ne__(self, other):
          return self._cmp(other) != 0
  
  
  def sortclonebundleentries(ui, entries):
      prefers = ui.configlist(b'ui', b'clonebundleprefers')
      if not prefers:
          return list(entries)
  
      def _split(p):
          if b'=' not in p:
              hint = _(b"each comma separated item should be key=value pairs")
              raise error.Abort(
                  _(b"invalid ui.clonebundleprefers item: %s") % p, hint=hint
              )
          return p.split(b'=', 1)
  
      prefers = [_split(p) for p in prefers]
  
      items = sorted(clonebundleentry(v, prefers) for v in entries)
      return [i.value for i in items]
  