text: # This file is part of h5py, a Python interface to the HDF5 library.
  #
  # http://www.h5py.org
  #
  # Copyright 2008-2013 Andrew Collette and contributors
  #
  # License:  Standard 3-clause BSD; see "license.txt" for full license terms
  #           and contributor agreement.
  
  """
      Implements operations common to all high-level objects (File, etc.).
  """
  
  from __future__ import absolute_import
  
  import posixpath
  import os
  import six
  
  try:
      from collections.abc import (Mapping, MutableMapping, KeysView,
                                   ValuesView, ItemsView)
  except ImportError:
      from collections import (Mapping, MutableMapping, KeysView,
                               ValuesView, ItemsView)
  
  from .compat import fspath, filename_encode
  
  from .. import h5d, h5i, h5r, h5p, h5f, h5t, h5s
  
  # The high-level interface is serialized; every public API function & method
  # is wrapped in a lock.  We re-use the low-level lock because (1) it's fast,
  # and (2) it eliminates the possibility of deadlocks due to out-of-order
  # lock acquisition.
  from .._objects import phil, with_phil
  
  
  def is_hdf5(fname):
      """ Determine if a file is valid HDF5 (False if it doesn't exist). """
      with phil:
          fname = os.path.abspath(fspath(fname))
  
          if os.path.isfile(fname):
              return h5f.is_hdf5(filename_encode(fname))
          return False
  
  
  def guess_dtype(data):
      """ Attempt to guess an appropriate dtype for the object, returning None
      if nothing is appropriate (or if it should be left up the the array
      constructor to figure out)
      """
      with phil:
          if isinstance(data, h5r.RegionReference):
              return h5t.special_dtype(ref=h5r.RegionReference)
          if isinstance(data, h5r.Reference):
              return h5t.special_dtype(ref=h5r.Reference)
          if type(data) == bytes:
              return h5t.special_dtype(vlen=bytes)
          if type(data) == six.text_type:
              return h5t.special_dtype(vlen=six.text_type)
  
          return None
  
  
  def default_lapl():
      """ Default link access property list """
      lapl = h5p.create(h5p.LINK_ACCESS)
      fapl = h5p.create(h5p.FILE_ACCESS)
      fapl.set_fclose_degree(h5f.CLOSE_STRONG)
      lapl.set_elink_fapl(fapl)
      return lapl
  
  
  def default_lcpl():
      """ Default link creation property list """
      lcpl = h5p.create(h5p.LINK_CREATE)
      lcpl.set_create_intermediate_group(True)
      return lcpl
  
  dlapl = default_lapl()
  dlcpl = default_lcpl()
  
  
  def is_empty_dataspace(obj):
      """ Check if an object's dataspace is empty """
      if obj.get_space().get_simple_extent_type() == h5s.NULL:
          return True
      return False
  
  
  class CommonStateObject(object):
  
      """
          Mixin class that allows sharing information between objects which
          reside in the same HDF5 file.  Requires that the host class have
          a ".id" attribute which returns a low-level ObjectID subclass.
  
          Also implements Unicode operations.
      """
  
      @property
      def _lapl(self):
          """ Fetch the link access property list appropriate for this object
          """
          return dlapl
  
      @property
      def _lcpl(self):
          """ Fetch the link creation property list appropriate for this object
          """
          return dlcpl
  
      def _e(self, name, lcpl=None):
          """ Encode a name according to the current file settings.
  
          Returns name, or 2-tuple (name, lcpl) if lcpl is True
  
          - Binary strings are always passed as-is, h5t.CSET_ASCII
          - Unicode strings are encoded utf8, h5t.CSET_UTF8
  
          If name is None, returns either None or (None, None) appropriately.
          """
          def get_lcpl(coding):
              """ Create an appropriate link creation property list """
              lcpl = self._lcpl.copy()
              lcpl.set_char_encoding(coding)
              return lcpl
  
          if name is None:
              return (None, None) if lcpl else None
  
          if isinstance(name, bytes):
              coding = h5t.CSET_ASCII
          else:
              try:
                  name = name.encode('ascii')
                  coding = h5t.CSET_ASCII
              except UnicodeEncodeError:
                  name = name.encode('utf8')
                  coding = h5t.CSET_UTF8
  
          if lcpl:
              return name, get_lcpl(coding)
          return name
  
      def _d(self, name):
          """ Decode a name according to the current file settings.
  
          - Try to decode utf8
          - Failing that, return the byte string
  
          If name is None, returns None.
          """
          if name is None:
              return None
  
          try:
              return name.decode('utf8')
          except UnicodeDecodeError:
              pass
          return name
  
  
  class _RegionProxy(object):
  
      """
          Proxy object which handles region references.
  
          To create a new region reference (datasets only), use slicing syntax:
  
              >>> newref = obj.regionref[0:10:2]
  
          To determine the target dataset shape from an existing reference:
  
              >>> shape = obj.regionref.shape(existingref)
  
          where <obj> may be any object in the file. To determine the shape of
          the selection in use on the target dataset:
  
              >>> selection_shape = obj.regionref.selection(existingref)
      """
  
      def __init__(self, obj):
          self.id = obj.id
  
      def __getitem__(self, args):
          if not isinstance(self.id, h5d.DatasetID):
              raise TypeError("Region references can only be made to datasets")
          from . import selections
          with phil:
              selection = selections.select(self.id.shape, args, dsid=self.id)
              return h5r.create(self.id, b'.', h5r.DATASET_REGION, selection.id)
  
      def shape(self, ref):
          """ Get the shape of the target dataspace referred to by *ref*. """
          with phil:
              sid = h5r.get_region(ref, self.id)
              return sid.shape
  
      def selection(self, ref):
          """ Get the shape of the target dataspace selection referred to by *ref*
          """
          from . import selections
          with phil:
              sid = h5r.get_region(ref, self.id)
              return selections.guess_shape(sid)
  
  
  class HLObject(CommonStateObject):
  
      """
          Base class for high-level interface objects.
      """
  
      @property
      def file(self):
          """ Return a File instance associated with this object """
          from . import files
          with phil:
              return files.File(self.id)
  
      @property
      @with_phil
      def name(self):
          """ Return the full name of this object.  None if anonymous. """
          return self._d(h5i.get_name(self.id))
  
      @property
      @with_phil
      def parent(self):
          """Return the parent group of this object.
  
          This is always equivalent to obj.file[posixpath.dirname(obj.name)].
          ValueError if this object is anonymous.
          """
          if self.name is None:
              raise ValueError("Parent of an anonymous object is undefined")
          return self.file[posixpath.dirname(self.name)]
  
      @property
      @with_phil
      def id(self):
          """ Low-level identifier appropriate for this object """
          return self._id
  
      @property
      @with_phil
      def ref(self):
          """ An (opaque) HDF5 reference to this object """
          return h5r.create(self.id, b'.', h5r.OBJECT)
  
      @property
      @with_phil
      def regionref(self):
          """Create a region reference (Datasets only).
  
          The syntax is regionref[<slices>]. For example, dset.regionref[...]
          creates a region reference in which the whole dataset is selected.
  
          Can also be used to determine the shape of the referenced dataset
          (via .shape property), or the shape of the selection (via the
          .selection property).
          """
          return _RegionProxy(self)
  
      @property
      def attrs(self):
          """ Attributes attached to this object """
          from . import attrs
          with phil:
              return attrs.AttributeManager(self)
  
      @with_phil
      def __init__(self, oid):
          """ Setup this object, given its low-level identifier """
          self._id = oid
  
      @with_phil
      def __hash__(self):
          return hash(self.id)
  
      @with_phil
      def __eq__(self, other):
          if hasattr(other, 'id'):
              return self.id == other.id
          return False
  
      @with_phil
      def __ne__(self, other):
          return not self.__eq__(other)
  
      def __bool__(self):
          with phil:
              return bool(self.id)
      __nonzero__ = __bool__
  
  
  # --- Dictionary-style interface ----------------------------------------------
  
  # To implement the dictionary-style interface from groups and attributes,
  # we inherit from the appropriate abstract base classes in collections.
  #
  # All locking is taken care of by the subclasses.
  # We have to override ValuesView and ItemsView here because Group and
  # AttributeManager can only test for key names.
  
  
  class KeysViewHDF5(KeysView):
      def __str__(self):
          k = ", ".join(repr(x) for x in self)
          return "hdf_keys([{}])".format(k)
      __repr__ = __str__
  
  class ValuesViewHDF5(ValuesView):
  
      """
          Wraps e.g. a Group or AttributeManager to provide a value view.
  
          Note that __contains__ will have poor performance as it has
          to scan all the links or attributes.
      """
  
      def __contains__(self, value):
          with phil:
              for key in self._mapping:
                  if value == self._mapping.get(key):
                      return True
              return False
  
      def __iter__(self):
          with phil:
              for key in self._mapping:
                  yield self._mapping.get(key)
  
  
  class ItemsViewHDF5(ItemsView):
  
      """
          Wraps e.g. a Group or AttributeManager to provide an items view.
      """
  
      def __contains__(self, item):
          with phil:
              key, val = item
              if key in self._mapping:
                  return val == self._mapping.get(key)
              return False
  
      def __iter__(self):
          with phil:
              for key in self._mapping:
                  yield (key, self._mapping.get(key))
  
  
  class MappingHDF5(Mapping):
  
      """
          Wraps a Group, AttributeManager or DimensionManager object to provide
          an immutable mapping interface.
  
          We don't inherit directly from MutableMapping because certain
          subclasses, for example DimensionManager, are read-only.
      """
      if six.PY2:
          def keys(self):
              """ Get a list containing member names """
              with phil:
                  return list(self)
  
          def values(self):
              """ Get a list containing member objects """
              with phil:
                  return [self.get(x) for x in self]
  
          def itervalues(self):
              """ Get an iterator over member objects """
              for x in self:
                  yield self.get(x)
  
          def items(self):
              """ Get a list of tuples containing (name, object) pairs """
              with phil:
                  return [(x, self.get(x)) for x in self]
  
          def iteritems(self):
              """ Get an iterator over (name, object) pairs """
              for x in self:
                  yield (x, self.get(x))
  
      else:
          def keys(self):
              """ Get a view object on member names """
              return KeysViewHDF5(self)
  
          def values(self):
              """ Get a view object on member objects """
              return ValuesViewHDF5(self)
  
          def items(self):
              """ Get a view object on member items """
              return ItemsViewHDF5(self)
  
  
  class MutableMappingHDF5(MappingHDF5, MutableMapping):
  
      """
          Wraps a Group or AttributeManager object to provide a mutable
          mapping interface, in contrast to the read-only mapping of
          MappingHDF5.
      """
  
      pass
  
  
  class Empty(object):
  
      """
          Proxy object to represent empty/null dataspaces (a.k.a H5S_NULL).
  
          This can have an associated dtype, but has no shape or data. This is not
          the same as an array with shape (0,).
      """
      shape = None
      size = None
  
      def __init__(self, dtype):
          self.dtype = dtype
  
      def __eq__(self, other):
          if isinstance(other, Empty) and self.dtype == other.dtype:
              return True
          return False
  
      def __repr__(self):
          return "Empty(dtype={0!r})".format(self.dtype)
  