# coding: utf-8
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# Copyright (C) 2016-2017 European Synchrotron Radiation Facility
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# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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"""
This module contains generic objects, emulating *h5py* groups, datasets and
files. They are used in :mod:`spech5` and :mod:`fabioh5`.
.. note:: This module has a dependency on the `h5py <http://www.h5py.org/>`_
library, which is not a mandatory dependency for `silx`.
"""
import collections
import h5py
import numpy
from silx.third_party import six
from .utils import is_dataset
__authors__ = ["V. Valls", "P. Knobel"]
__license__ = "MIT"
__date__ = "02/10/2017"
class _MappingProxyType(collections.MutableMapping):
"""Read-only dictionary
This class is available since Python 3.3, but not on earlyer Python
versions.
"""
def __init__(self, data):
self._data = data
def __getitem__(self, key):
return self._data[key]
def __len__(self):
return len(self._data)
def __iter__(self):
return iter(self._data)
def get(self, key, default=None):
return self._data.get(key, default)
def __setitem__(self, key, value):
raise RuntimeError("Cannot modify read-only dictionary")
def __delitem__(self, key):
raise RuntimeError("Cannot modify read-only dictionary")
def pop(self, key):
raise RuntimeError("Cannot modify read-only dictionary")
def clear(self):
raise RuntimeError("Cannot modify read-only dictionary")
def update(self, key, value):
raise RuntimeError("Cannot modify read-only dictionary")
def setdefault(self, key):
raise RuntimeError("Cannot modify read-only dictionary")
class Node(object):
"""This is the base class for all :mod:`spech5` and :mod:`fabioh5`
classes. It represents a tree node, and knows its parent node
(:attr:`parent`).
The API mimics a *h5py* node, with following attributes: :attr:`file`,
:attr:`attrs`, :attr:`name`, and :attr:`basename`.
"""
def __init__(self, name, parent=None, attrs=None):
self.__parent = parent
self.__basename = name
self.__attrs = {}
if attrs is not None:
self.__attrs.update(attrs)
def _set_basename(self, name):
self.__basename = name
@property
def h5py_class(self):
"""Returns the h5py classes which is mimicked by this class. It can be
one of `h5py.File, h5py.Group` or `h5py.Dataset`
:rtype: Class
"""
raise NotImplementedError()
@property
def parent(self):
"""Returns the parent of the node.
:rtype: Node
"""
return self.__parent
@property
def file(self):
"""Returns the file node of this node.
:rtype: Node
"""
node = self
while node.__parent is not None:
node = node.__parent
if isinstance(node, File):
return node
else:
return None
def _set_parent(self, parent):
"""Set the parent of this node.
It do not update the parent object.
:param Node parent: New parent for this node
"""
self.__parent = parent
@property
def attrs(self):
"""Returns HDF5 attributes of this node.
:rtype: dict
"""
if self._is_editable():
return self.__attrs
else:
return _MappingProxyType(self.__attrs)
@property
def name(self):
"""Returns the HDF5 name of this node.
"""
if self.__parent is None:
return "/"
if self.__parent.name == "/":
return "/" + self.basename
return self.__parent.name + "/" + self.basename
@property
def basename(self):
"""Returns the HDF5 basename of this node.
"""
return self.__basename
def _is_editable(self):
"""Returns true if the file is editable or if the node is not linked
to a tree.
:rtype: bool
"""
f = self.file
return f is None or f.mode == "w"
class Dataset(Node):
"""This class handles a numpy data object, as a mimicry of a
*h5py.Dataset*.
"""
def __init__(self, name, data, parent=None, attrs=None):
Node.__init__(self, name, parent, attrs=attrs)
if data is not None:
self._check_data(data)
self.__data = data
def _check_data(self, data):
"""Check that the data provided by the dataset is valid.
It is valid when it can be stored in a HDF5 using h5py.
:param numpy.ndarray data: Data associated to the dataset
:raises TypeError: In the case the data is not valid.
"""
if isinstance(data, (six.text_type, six.binary_type)):
return
chartype = data.dtype.char
if chartype == "U":
pass
elif chartype == "O":
d = h5py.special_dtype(vlen=data.dtype)
if d is not None:
return
d = h5py.special_dtype(ref=data.dtype)
if d is not None:
return
else:
return
msg = "Type of the dataset '%s' is not supported. Found '%s'."
raise TypeError(msg % (self.name, data.dtype))
def _set_data(self, data):
"""Set the data exposed by the dataset.
It have to be called only one time before the data is used. It should
not be edited after use.
:param numpy.ndarray data: Data associated to the dataset
"""
self._check_data(data)
self.__data = data
def _get_data(self):
"""Returns the exposed data
:rtype: numpy.ndarray
"""
return self.__data
@property
def h5py_class(self):
"""Returns the h5py classes which is mimicked by this class. It can be
one of `h5py.File, h5py.Group` or `h5py.Dataset`
:rtype: Class
"""
return h5py.Dataset
@property
def dtype(self):
"""Returns the numpy datatype exposed by this dataset.
:rtype: numpy.dtype
"""
return self._get_data().dtype
@property
def shape(self):
"""Returns the shape of the data exposed by this dataset.
:rtype: tuple
"""
if isinstance(self._get_data(), numpy.ndarray):
return self._get_data().shape
else:
return tuple()
@property
def size(self):
"""Returns the size of the data exposed by this dataset.
:rtype: int
"""
if isinstance(self._get_data(), numpy.ndarray):
return self._get_data().size
else:
# It is returned as float64 1.0 by h5py
return numpy.float64(1.0)
def __len__(self):
"""Returns the size of the data exposed by this dataset.
:rtype: int
"""
if isinstance(self._get_data(), numpy.ndarray):
return len(self._get_data())
else:
# It is returned as float64 1.0 by h5py
raise TypeError("Attempt to take len() of scalar dataset")
def __getitem__(self, item):
"""Returns the slice of the data exposed by this dataset.
:rtype: numpy.ndarray
"""
if not isinstance(self._get_data(), numpy.ndarray):
if item == Ellipsis:
return numpy.array(self._get_data())
elif item == tuple():
return self._get_data()
else:
raise ValueError("Scalar can only be reached with an ellipsis or an empty tuple")
return self._get_data().__getitem__(item)
def __str__(self):
basename = self.name.split("/")[-1]
return '<HDF5-like dataset "%s": shape %s, type "%s">' % \
(basename, self.shape, self.dtype.str)
def __getslice__(self, i, j):
"""Returns the slice of the data exposed by this dataset.
Deprecated but still in use for python 2.7
:rtype: numpy.ndarray
"""
return self.__getitem__(slice(i, j, None))
@property
def value(self):
"""Returns the data exposed by this dataset.
Deprecated by h5py. It is prefered to use indexing `[()]`.
:rtype: numpy.ndarray
"""
return self._get_data()
@property
def compression(self):
"""Returns compression as provided by `h5py.Dataset`.
There is no compression."""
return None
@property
def compression_opts(self):
"""Returns compression options as provided by `h5py.Dataset`.
There is no compression."""
return None
@property
def chunks(self):
"""Returns chunks as provided by `h5py.Dataset`.
There is no chunks."""
return None
def __array__(self, dtype=None):
# Special case for (0,)*-shape datasets
if numpy.product(self.shape) == 0:
return self[()]
else:
return numpy.array(self[...], dtype=self.dtype if dtype is None else dtype)
def __iter__(self):
"""Iterate over the first axis. TypeError if scalar."""
if len(self.shape) == 0:
raise TypeError("Can't iterate over a scalar dataset")
return self._get_data().__iter__()
# make comparisons and operations on the data
def __eq__(self, other):
"""When comparing datasets, compare the actual data."""
if is_dataset(other):
return self[()] == other[()]
return self[()] == other
def __add__(self, other):
return self[()] + other
def __radd__(self, other):
return other + self[()]
def __sub__(self, other):
return self[()] - other
def __rsub__(self, other):
return other - self[()]
def __mul__(self, other):
return self[()] * other
def __rmul__(self, other):
return other * self[()]
def __truediv__(self, other):
return self[()] / other
def __rtruediv__(self, other):
return other / self[()]
def __floordiv__(self, other):
return self[()] // other
def __rfloordiv__(self, other):
return other // self[()]
def __neg__(self):
return -self[()]
def __abs__(self):
return abs(self[()])
def __float__(self):
return float(self[()])
def __int__(self):
return int(self[()])
def __bool__(self):
if self[()]:
return True
return False
def __nonzero__(self):
# python 2
return self.__bool__()
def __ne__(self, other):
if is_dataset(other):
return self[()] != other[()]
else:
return self[()] != other
def __lt__(self, other):
if is_dataset(other):
return self[()] < other[()]
else:
return self[()] < other
def __le__(self, other):
if is_dataset(other):
return self[()] <= other[()]
else:
return self[()] <= other
def __gt__(self, other):
if is_dataset(other):
return self[()] > other[()]
else:
return self[()] > other
def __ge__(self, other):
if is_dataset(other):
return self[()] >= other[()]
else:
return self[()] >= other
def __getattr__(self, item):
"""Proxy to underlying numpy array methods.
"""
data = self._get_data()
if hasattr(data, item):
return getattr(data, item)
raise AttributeError("Dataset has no attribute %s" % item)
class _LinkToDataset(Dataset):
"""Virtual dataset providing link to another dataset"""
def __init__(self, name, target, parent=None):
Dataset.__init__(self, name, data=None, parent=parent)
self.__target = target
def _get_data(self):
return self.__target._get_data()
@property
def attrs(self):
return self.__target.attrs
class LazyLoadableDataset(Dataset):
"""Abstract dataset which provides a lazy loading of the data.
The class has to be inherited and the :meth:`_create_data` method has to be
implemented to return the numpy data exposed by the dataset. This factory
method is only called once, when the data is needed.
"""
def __init__(self, name, parent=None, attrs=None):
super(LazyLoadableDataset, self).__init__(name, None, parent, attrs=attrs)
self._is_initialized = False
def _create_data(self):
"""
Factory to create the data exposed by the dataset when it is needed.
It has to be implemented for the class to work.
:rtype: numpy.ndarray
"""
raise NotImplementedError()
def _get_data(self):
"""Returns the data exposed by the dataset.
Overwrite Dataset method :meth:`_get_data` to implement the lazy
loading feature.
:rtype: numpy.ndarray
"""
if not self._is_initialized:
data = self._create_data()
# is_initialized before set_data to avoid infinit initialization
# is case of wrong check of the data
self._is_initialized = True
self._set_data(data)
return super(LazyLoadableDataset, self)._get_data()
class SoftLink(Node):
"""This class is a tree node that mimics a *h5py.Softlink*.
In this implementation, the path to the target must be absolute.
"""
def __init__(self, name, path, parent=None):
assert str(path).startswith("/") # TODO: h5py also allows a relative path
Node.__init__(self, name, parent)
# attr target defined for spech5 backward compatibility
self.target = str(path)
@property
def h5py_class(self):
"""Returns the h5py class which is mimicked by this class
(:class:`h5py.SoftLink`).
:rtype: Class
"""
return h5py.SoftLink
@property
def path(self):
"""Soft link value. Not guaranteed to be a valid path."""
return self.target
[docs]class Group(Node):
"""This class mimics a `h5py.Group`."""
def __init__(self, name, parent=None, attrs=None):
Node.__init__(self, name, parent, attrs=attrs)
self.__items = collections.OrderedDict()
def _get_items(self):
"""Returns the child items as a name-node dictionary.
:rtype: dict
"""
return self.__items
def add_node(self, node):
"""Add a child to this group.
:param Node node: Child to add to this group
"""
self._get_items()[node.basename] = node
node._set_parent(self)
@property
def h5py_class(self):
"""Returns the h5py classes which is mimicked by this class.
It returns `h5py.Group`
:rtype: Class
"""
return h5py.Group
def _get(self, name, getlink):
"""If getlink is True and name points to an existing SoftLink, this
SoftLink is returned. In all other situations, we try to return a
Group or Dataset, or we raise a KeyError if we fail."""
if "/" not in name:
result = self._get_items()[name]
elif name.startswith("/"):
root = self.file
if name == "/":
return root
result = root._get(name[1:], getlink)
else:
path = name.split("/")
result = self
for item_name in path:
if isinstance(result, SoftLink):
# traverse links
l_name, l_target = result.name, result.path
result = result.file.get(l_target)
if result is None:
raise KeyError(
"Unable to open object (broken SoftLink %s -> %s)" %
(l_name, l_target))
if not item_name:
# trailing "/" in name (legal for accessing Groups only)
if isinstance(result, Group):
continue
if not isinstance(result, Group):
raise KeyError("Unable to open object (Component not found)")
result = result._get_items()[item_name]
if isinstance(result, SoftLink) and not getlink:
link = result
target = result.file.get(link.path)
if result is None:
msg = "Unable to open object (broken SoftLink %s -> %s)"
raise KeyError(msg % (link.name, link.path))
# Convert SoftLink into typed group/dataset
if isinstance(target, Group):
result = _LinkToGroup(name=link.basename, target=target, parent=link.parent)
elif isinstance(target, Dataset):
result = _LinkToDataset(name=link.basename, target=target, parent=link.parent)
else:
raise TypeError("Unexpected target type %s" % type(target))
return result
[docs] def get(self, name, default=None, getclass=False, getlink=False):
"""Retrieve an item or other information.
If getlink only is true, the returned value is always `h5py.HardLink`,
because this implementation do not use links. Like the original
implementation.
:param str name: name of the item
:param object default: default value returned if the name is not found
:param bool getclass: if true, the returned object is the class of the object found
:param bool getlink: if true, links object are returned instead of the target
:return: An object, else None
:rtype: object
"""
if name not in self:
return default
node = self._get(name, getlink=True)
if isinstance(node, SoftLink) and not getlink:
# get target
try:
node = self._get(name, getlink=False)
except KeyError:
return default
elif not isinstance(node, SoftLink) and getlink:
# ExternalLink objects don't exist in silx, so it must be a HardLink
node = h5py.HardLink()
if getclass:
if hasattr(node, "h5py_class"):
obj = node.h5py_class
else:
obj = node.__class__
else:
obj = node
return obj
def __setitem__(self, name, obj):
"""Add an object to the group.
:param str name: Location on the group to store the object.
This path name must not exists.
:param object obj: Object to store on the file. According to the type,
the behaviour will not be the same.
- `commonh5.SoftLink`: Create the corresponding link.
- `numpy.ndarray`: The array is converted to a dataset object.
- `commonh5.Node`: A hard link should be created pointing to the
given object. This implementation uses a soft link.
If the node do not have parent it is connected to the tree
without using a link (that's a hard link behaviour).
- other object: Convert first the object with ndarray and then
store it. ValueError if the resulting array dtype is not
supported.
"""
if name in self:
# From the h5py API
raise RuntimeError("Unable to create link (name already exists)")
elements = name.rsplit("/", 1)
if len(elements) == 1:
parent = self
basename = elements[0]
else:
group_path, basename = elements
if group_path in self:
parent = self[group_path]
else:
parent = self.create_group(group_path)
if isinstance(obj, SoftLink):
obj._set_basename(basename)
node = obj
elif isinstance(obj, Node):
if obj.parent is None:
obj._set_basename(basename)
node = obj
else:
node = SoftLink(basename, obj.name)
elif isinstance(obj, numpy.dtype):
node = Dataset(basename, data=obj)
elif isinstance(obj, numpy.ndarray):
node = Dataset(basename, data=obj)
else:
data = numpy.array(obj)
try:
node = Dataset(basename, data=data)
except TypeError as e:
raise ValueError(e.args[0])
parent.add_node(node)
def __getitem__(self, name):
"""Return a child from his name.
:param name str: name of a member or a path throug members using '/'
separator. A '/' as a prefix access to the root item of the tree.
:rtype: Node
"""
if name is None or name == "":
raise ValueError("No name")
return self._get(name, getlink=False)
def __contains__(self, name):
"""Returns true if name is an existing child of this group.
:rtype: bool
"""
if "/" not in name:
return name in self._get_items()
if name.startswith("/"):
# h5py allows to access any valid full path from any group
node = self.file
else:
node = self
name = name.lstrip("/")
basenames = name.split("/")
for basename in basenames:
if basename.strip() == "":
# presence of a trailing "/" in name
# (OK for groups, not for datasets)
if isinstance(node, SoftLink):
# traverse links
node = node.file.get(node.path, getlink=False)
if node is None:
# broken link
return False
if node.h5py_class == h5py.Dataset:
return False
continue
if basename not in node._get_items():
return False
node = node[basename]
return True
def __len__(self):
"""Returns the number of children contained in this group.
:rtype: int
"""
return len(self._get_items())
def __iter__(self):
"""Iterate over member names"""
for x in self._get_items().__iter__():
yield x
if six.PY2:
def keys(self):
"""Returns a list of the children's names."""
return self._get_items().keys()
def values(self):
"""Returns a list of the children nodes (groups and datasets).
.. versionadded:: 0.6
"""
return self._get_items().values()
def items(self):
"""Returns a list of tuples containing (name, node) pairs.
"""
return self._get_items().items()
else:
[docs] def keys(self):
"""Returns an iterator over the children's names in a group."""
return self._get_items().keys()
[docs] def values(self):
"""Returns an iterator over the children nodes (groups and datasets)
in a group.
.. versionadded:: 0.6
"""
return self._get_items().values()
[docs] def items(self):
"""Returns items iterator containing name-node mapping.
:rtype: iterator
"""
return self._get_items().items()
[docs] def visit(self, func, visit_links=False):
"""Recursively visit all names in this group and subgroups.
See the documentation for `h5py.Group.visit` for more help.
:param func: Callable (function, method or callable object)
:type func: function
"""
origin_name = self.name
return self._visit(func, origin_name, visit_links)
[docs] def visititems(self, func, visit_links=False):
"""Recursively visit names and objects in this group.
See the documentation for `h5py.Group.visititems` for more help.
:param func: Callable (function, method or callable object)
:type func: function
:param bool visit_links: If *False*, ignore links. If *True*,
call `func(name)` for links and recurse into target groups.
"""
origin_name = self.name
return self._visit(func, origin_name, visit_links,
visititems=True)
def _visit(self, func, origin_name,
visit_links=False, visititems=False):
"""
:param origin_name: name of first group that initiated the recursion
This is used to compute the relative path from each item's
absolute path.
"""
for member in self.values():
ret = None
if not isinstance(member, SoftLink) or visit_links:
relative_name = member.name[len(origin_name):]
# remove leading slash and unnecessary trailing slash
relative_name = relative_name.strip("/")
if visititems:
ret = func(relative_name, member)
else:
ret = func(relative_name)
if ret is not None:
return ret
if isinstance(member, Group):
member._visit(func, origin_name, visit_links, visititems)
def create_group(self, name):
"""Create and return a new subgroup.
Name may be absolute or relative. Fails if the target name already
exists.
:param str name: Name of the new group
"""
if not self._is_editable():
raise RuntimeError("File is not editable")
if name in self:
raise ValueError("Unable to create group (name already exists)")
if name.startswith("/"):
name = name[1:]
return self.file.create_group(name)
elements = name.split('/')
group = self
for basename in elements:
if basename in group:
group = group[basename]
if not isinstance(group, Group):
raise RuntimeError("Unable to create group (group parent is missing")
else:
node = Group(basename)
group.add_node(node)
group = node
return group
def create_dataset(self, name, shape=None, dtype=None, data=None, **kwds):
"""Create and return a sub dataset.
:param str name: Name of the dataset.
:param shape: Dataset shape. Use "()" for scalar datasets.
Required if "data" isn't provided.
:param dtype: Numpy dtype or string.
If omitted, dtype('f') will be used.
Required if "data" isn't provided; otherwise, overrides data
array's dtype.
:param numpy.ndarray data: Provide data to initialize the dataset.
If used, you can omit shape and dtype arguments.
:param kwds: Extra arguments. Nothing yet supported.
"""
if not self._is_editable():
raise RuntimeError("File is not editable")
if len(kwds) > 0:
raise TypeError("Extra args provided, but nothing supported")
if "/" in name:
raise TypeError("Path are not supported")
if data is None:
if dtype is None:
dtype = numpy.float
data = numpy.empty(shape=shape, dtype=dtype)
elif dtype is not None:
data = data.astype(dtype)
dataset = Dataset(name, data)
self.add_node(dataset)
return dataset
class _LinkToGroup(Group):
"""Virtual group providing link to another group"""
def __init__(self, name, target, parent=None):
Group.__init__(self, name, parent=parent)
self.__target = target
def _get_items(self):
return self.__target._get_items()
@property
def attrs(self):
return self.__target.attrs
class LazyLoadableGroup(Group):
"""Abstract group which provides a lazy loading of the child.
The class has to be inherited and the :meth:`_create_child` method has
to be implemented to add (:meth:`_add_node`) all children. This factory
is only called once, when children are needed.
"""
def __init__(self, name, parent=None, attrs=None):
Group.__init__(self, name, parent, attrs)
self.__is_initialized = False
def _get_items(self):
"""Returns the internal structure which contains the children.
It overwrite method :meth:`_get_items` to implement the lazy
loading feature.
:rtype: dict
"""
if not self.__is_initialized:
self.__is_initialized = True
self._create_child()
return Group._get_items(self)
def _create_child(self):
"""
Factory to create the child contained by the group when it is needed.
It has to be implemented to work.
"""
raise NotImplementedError()
class File(Group):
"""This class is the special :class:`Group` that is the root node
of the tree structure. It mimics `h5py.File`."""
def __init__(self, name=None, mode=None, attrs=None):
"""
Constructor
:param str name: File name if it exists
:param str mode: Access mode
- "r": Read-only. Methods :meth:`create_dataset` and
:meth:`create_group` are locked.
- "w": File is editable. Methods :meth:`create_dataset` and
:meth:`create_group` are available.
:param dict attrs: Default attributes
"""
Group.__init__(self, name="", parent=None, attrs=attrs)
self._file_name = name
if mode is None:
mode = "r"
assert(mode in ["r", "w"])
self._mode = mode
@property
def filename(self):
return self._file_name
@property
def mode(self):
return self._mode
@property
def h5py_class(self):
"""Returns the :class:`h5py.File` class"""
return h5py.File
def __enter__(self):
return self
def __exit__(self, exc_type, exc_val, exc_tb):
self.close()
def close(self):
"""Close the object, and free up associated resources.
"""
# should be implemented in subclass
pass
