"""

Helper functions for managing the Matplotlib API.

This documentation is only relevant for Matplotlib developers, not for users.

.. warning::

This module and its submodules are for internal use only. Do not use them

in your own code. We may change the API at any time with no warning.

"""

import functools

import itertools

import pathlib

import re

import sys

import warnings

from .deprecation import ( # noqa: F401

deprecated, warn_deprecated,

rename_parameter, delete_parameter, make_keyword_only,

deprecate_method_override, deprecate_privatize_attribute,

suppress_matplotlib_deprecation_warning,

MatplotlibDeprecationWarning)

class classproperty:

"""

Like `property`, but also triggers on access via the class, and it is the

*class* that's passed as argument.

Examples

--------

::

class C:

@classproperty

def foo(cls):

return cls.__name__

assert C.foo == "C"

"""

def __init__(self, fget, fset=None, fdel=None, doc=None):

self._fget = fget

if fset is not None or fdel is not None:

raise ValueError('classproperty only implements fget.')

self.fset = fset

self.fdel = fdel

# docs are ignored for now

self._doc = doc

def __get__(self, instance, owner):

return self._fget(owner)

@property

def fget(self):

return self._fget

# In the following check_foo() functions, the first parameter is positional-only to make

# e.g. `_api.check_isinstance([...], types=foo)` work.

def check_isinstance(types, /, **kwargs):

"""

For each *key, value* pair in *kwargs*, check that *value* is an instance

of one of *types*; if not, raise an appropriate TypeError.

As a special case, a ``None`` entry in *types* is treated as NoneType.

Examples

--------

>>> _api.check_isinstance((SomeClass, None), arg=arg)

"""

none_type = type(None)

types = ((types,) if isinstance(types, type) else

(none_type,) if types is None else

tuple(none_type if tp is None else tp for tp in types))

def type_name(tp):

return ("None" if tp is none_type

else tp.__qualname__ if tp.__module__ == "builtins"

else f"{tp.__module__}.{tp.__qualname__}")

for k, v in kwargs.items():

if not isinstance(v, types):

names = [*map(type_name, types)]

if "None" in names: # Move it to the end for better wording.

names.remove("None")

names.append("None")

raise TypeError(

"{!r} must be an instance of {}, not a {}".format(

k,

", ".join(names[:-1]) + " or " + names[-1]

if len(names) > 1 else names[0],

type_name(type(v))))

def check_in_list(values, /, *, _print_supported_values=True, **kwargs):

"""

For each *key, value* pair in *kwargs*, check that *value* is in *values*;

if not, raise an appropriate ValueError.

Parameters

----------

values : iterable

Sequence of values to check on.

_print_supported_values : bool, default: True

Whether to print *values* when raising ValueError.

**kwargs : dict

*key, value* pairs as keyword arguments to find in *values*.

Raises

------

ValueError

If any *value* in *kwargs* is not found in *values*.

Examples

--------

>>> _api.check_in_list(["foo", "bar"], arg=arg, other_arg=other_arg)

"""

if not kwargs:

raise TypeError("No argument to check!")

for key, val in kwargs.items():

if val not in values:

msg = f"{val!r} is not a valid value for {key}"

if _print_supported_values:

msg += f"; supported values are {', '.join(map(repr, values))}"

raise ValueError(msg)

def check_shape(shape, /, **kwargs):

"""

For each *key, value* pair in *kwargs*, check that *value* has the shape *shape*;

if not, raise an appropriate ValueError.

*None* in the shape is treated as a "free" size that can have any length.

e.g. (None, 2) -> (N, 2)

The values checked must be numpy arrays.

Examples

--------

To check for (N, 2) shaped arrays

>>> _api.check_shape((None, 2), arg=arg, other_arg=other_arg)

"""

for k, v in kwargs.items():

data_shape = v.shape

if (len(data_shape) != len(shape)

or any(s != t and t is not None for s, t in zip(data_shape, shape))):

dim_labels = iter(itertools.chain(

'NMLKJIH',

(f"D{i}" for i in itertools.count())))

text_shape = ", ".join([str(n) if n is not None else next(dim_labels)

for n in shape[::-1]][::-1])

if len(shape) == 1:

text_shape += ","

raise ValueError(

f"{k!r} must be {len(shape)}D with shape ({text_shape}), "

f"but your input has shape {v.shape}"

)

def check_getitem(mapping, /, **kwargs):

"""

*kwargs* must consist of a single *key, value* pair. If *key* is in

*mapping*, return ``mapping[value]``; else, raise an appropriate

ValueError.

Examples

--------

>>> _api.check_getitem({"foo": "bar"}, arg=arg)

"""

if len(kwargs) != 1:

raise ValueError("check_getitem takes a single keyword argument")

(k, v), = kwargs.items()

try:

return mapping[v]

except KeyError:

raise ValueError(

f"{v!r} is not a valid value for {k}; supported values are "

f"{', '.join(map(repr, mapping))}") from None

def caching_module_getattr(cls):

"""

Helper decorator for implementing module-level ``__getattr__`` as a class.

This decorator must be used at the module toplevel as follows::

@caching_module_getattr

class __getattr__: # The class *must* be named ``__getattr__``.

@property # Only properties are taken into account.

def name(self): ...

The ``__getattr__`` class will be replaced by a ``__getattr__``

function such that trying to access ``name`` on the module will

resolve the corresponding property (which may be decorated e.g. with

``_api.deprecated`` for deprecating module globals). The properties are

all implicitly cached. Moreover, a suitable AttributeError is generated

and raised if no property with the given name exists.

"""

assert cls.__name__ == "__getattr__"

# Don't accidentally export cls dunders.

props = {name: prop for name, prop in vars(cls).items()

if isinstance(prop, property)}

instance = cls()

@functools.cache

def __getattr__(name):

if name in props:

return props[name].__get__(instance)

raise AttributeError(

f"module {cls.__module__!r} has no attribute {name!r}")

return __getattr__

def define_aliases(alias_d, cls=None):

"""

Class decorator for defining property aliases.

Use as ::

@_api.define_aliases({"property": ["alias", ...], ...})

class C: ...

For each property, if the corresponding ``get_property`` is defined in the

class so far, an alias named ``get_alias`` will be defined; the same will

be done for setters. If neither the getter nor the setter exists, an

exception will be raised.

The alias map is stored as the ``_alias_map`` attribute on the class and

can be used by `.normalize_kwargs` (which assumes that higher priority

aliases come last).

"""

if cls is None: # Return the actual class decorator.

return functools.partial(define_aliases, alias_d)

def make_alias(name): # Enforce a closure over *name*.

@functools.wraps(getattr(cls, name))

def method(self, *args, **kwargs):

return getattr(self, name)(*args, **kwargs)

return method

for prop, aliases in alias_d.items():

exists = False

for prefix in ["get_", "set_"]:

if prefix + prop in vars(cls):

exists = True

for alias in aliases:

method = make_alias(prefix + prop)

method.__name__ = prefix + alias

method.__doc__ = f"Alias for `{prefix + prop}`."

setattr(cls, prefix + alias, method)

if not exists:

raise ValueError(

f"Neither getter nor setter exists for {prop!r}")

def get_aliased_and_aliases(d):

return {*d, *(alias for aliases in d.values() for alias in aliases)}

preexisting_aliases = getattr(cls, "_alias_map", {})

conflicting = (get_aliased_and_aliases(preexisting_aliases)

& get_aliased_and_aliases(alias_d))

if conflicting:

# Need to decide on conflict resolution policy.

raise NotImplementedError(

f"Parent class already defines conflicting aliases: {conflicting}")

cls._alias_map = {**preexisting_aliases, **alias_d}

return cls

def select_matching_signature(funcs, *args, **kwargs):

"""

Select and call the function that accepts ``*args, **kwargs``.

*funcs* is a list of functions which should not raise any exception (other

than `TypeError` if the arguments passed do not match their signature).

`select_matching_signature` tries to call each of the functions in *funcs*

with ``*args, **kwargs`` (in the order in which they are given). Calls

that fail with a `TypeError` are silently skipped. As soon as a call

succeeds, `select_matching_signature` returns its return value. If no

function accepts ``*args, **kwargs``, then the `TypeError` raised by the

last failing call is re-raised.

Callers should normally make sure that any ``*args, **kwargs`` can only

bind a single *func* (to avoid any ambiguity), although this is not checked

by `select_matching_signature`.

Notes

-----

`select_matching_signature` is intended to help implementing

signature-overloaded functions. In general, such functions should be

avoided, except for back-compatibility concerns. A typical use pattern is

::

def my_func(*args, **kwargs):

params = select_matching_signature(

[lambda old1, old2: locals(), lambda new: locals()],

*args, **kwargs)

if "old1" in params:

warn_deprecated(...)

old1, old2 = params.values() # note that locals() is ordered.

else:

new, = params.values()

# do things with params

which allows *my_func* to be called either with two parameters (*old1* and

*old2*) or a single one (*new*). Note that the new signature is given

last, so that callers get a `TypeError` corresponding to the new signature

if the arguments they passed in do not match any signature.

"""

# Rather than relying on locals() ordering, one could have just used func's

# signature (``bound = inspect.signature(func).bind(*args, **kwargs);

# bound.apply_defaults(); return bound``) but that is significantly slower.

for i, func in enumerate(funcs):

try:

return func(*args, **kwargs)

except TypeError:

if i == len(funcs) - 1:

raise

def nargs_error(name, takes, given):

"""Generate a TypeError to be raised by function calls with wrong arity."""

return TypeError(f"{name}() takes {takes} positional arguments but "

f"{given} were given")

def kwarg_error(name, kw):

"""

Generate a TypeError to be raised by function calls with wrong kwarg.

Parameters

----------

name : str

The name of the calling function.

kw : str or Iterable[str]

Either the invalid keyword argument name, or an iterable yielding

invalid keyword arguments (e.g., a ``kwargs`` dict).

"""

if not isinstance(kw, str):

kw = next(iter(kw))

return TypeError(f"{name}() got an unexpected keyword argument '{kw}'")

def recursive_subclasses(cls):

"""Yield *cls* and direct and indirect subclasses of *cls*."""

yield cls

for subcls in cls.__subclasses__():

yield from recursive_subclasses(subcls)

def warn_external(message, category=None):

"""

`warnings.warn` wrapper that sets *stacklevel* to "outside Matplotlib".

The original emitter of the warning can be obtained by patching this

function back to `warnings.warn`, i.e. ``_api.warn_external =

warnings.warn`` (or ``functools.partial(warnings.warn, stacklevel=2)``,

etc.).

"""

kwargs = {}

if sys.version_info[:2] >= (3, 12):

# Go to Python's `site-packages` or `lib` from an editable install.

basedir = pathlib.Path(__file__).parents[2]

kwargs['skip_file_prefixes'] = (str(basedir / 'matplotlib'),

str(basedir / 'mpl_toolkits'))

else:

frame = sys._getframe()

for stacklevel in itertools.count(1):

if frame is None:

# when called in embedded context may hit frame is None

kwargs['stacklevel'] = stacklevel

break

if not re.match(r"\A(matplotlib|mpl_toolkits)(\Z|\.(?!tests\.))",

# Work around sphinx-gallery not setting __name__.

frame.f_globals.get("__name__", "")):

kwargs['stacklevel'] = stacklevel

break

frame = frame.f_back

# preemptively break reference cycle between locals and the frame

del frame

warnings.warn(message, category, **kwargs)