Current File : //opt/hc_python/lib64/python3.8/site-packages/sqlalchemy/sql/lambdas.py
# sql/lambdas.py
# Copyright (C) 2005-2024 the SQLAlchemy authors and contributors
# <see AUTHORS file>
#
# This module is part of SQLAlchemy and is released under
# the MIT License: https://www.opensource.org/licenses/mit-license.php
# mypy: allow-untyped-defs, allow-untyped-calls
from __future__ import annotations
import collections.abc as collections_abc
import inspect
import itertools
import operator
import threading
import types
from types import CodeType
from typing import Any
from typing import Callable
from typing import cast
from typing import List
from typing import MutableMapping
from typing import Optional
from typing import Tuple
from typing import Type
from typing import TYPE_CHECKING
from typing import TypeVar
from typing import Union
import weakref
from . import cache_key as _cache_key
from . import coercions
from . import elements
from . import roles
from . import schema
from . import visitors
from .base import _clone
from .base import Executable
from .base import Options
from .cache_key import CacheConst
from .operators import ColumnOperators
from .. import exc
from .. import inspection
from .. import util
from ..util.typing import Literal
if TYPE_CHECKING:
from .elements import BindParameter
from .elements import ClauseElement
from .roles import SQLRole
from .visitors import _CloneCallableType
_LambdaCacheType = MutableMapping[
Tuple[Any, ...], Union["NonAnalyzedFunction", "AnalyzedFunction"]
]
_BoundParameterGetter = Callable[..., Any]
_closure_per_cache_key: _LambdaCacheType = util.LRUCache(1000)
_LambdaType = Callable[[], Any]
_AnyLambdaType = Callable[..., Any]
_StmtLambdaType = Callable[[], Any]
_E = TypeVar("_E", bound=Executable)
_StmtLambdaElementType = Callable[[_E], Any]
class LambdaOptions(Options):
enable_tracking = True
track_closure_variables = True
track_on: Optional[object] = None
global_track_bound_values = True
track_bound_values = True
lambda_cache: Optional[_LambdaCacheType] = None
def lambda_stmt(
lmb: _StmtLambdaType,
enable_tracking: bool = True,
track_closure_variables: bool = True,
track_on: Optional[object] = None,
global_track_bound_values: bool = True,
track_bound_values: bool = True,
lambda_cache: Optional[_LambdaCacheType] = None,
) -> StatementLambdaElement:
"""Produce a SQL statement that is cached as a lambda.
The Python code object within the lambda is scanned for both Python
literals that will become bound parameters as well as closure variables
that refer to Core or ORM constructs that may vary. The lambda itself
will be invoked only once per particular set of constructs detected.
E.g.::
from sqlalchemy import lambda_stmt
stmt = lambda_stmt(lambda: table.select())
stmt += lambda s: s.where(table.c.id == 5)
result = connection.execute(stmt)
The object returned is an instance of :class:`_sql.StatementLambdaElement`.
.. versionadded:: 1.4
:param lmb: a Python function, typically a lambda, which takes no arguments
and returns a SQL expression construct
:param enable_tracking: when False, all scanning of the given lambda for
changes in closure variables or bound parameters is disabled. Use for
a lambda that produces the identical results in all cases with no
parameterization.
:param track_closure_variables: when False, changes in closure variables
within the lambda will not be scanned. Use for a lambda where the
state of its closure variables will never change the SQL structure
returned by the lambda.
:param track_bound_values: when False, bound parameter tracking will
be disabled for the given lambda. Use for a lambda that either does
not produce any bound values, or where the initial bound values never
change.
:param global_track_bound_values: when False, bound parameter tracking
will be disabled for the entire statement including additional links
added via the :meth:`_sql.StatementLambdaElement.add_criteria` method.
:param lambda_cache: a dictionary or other mapping-like object where
information about the lambda's Python code as well as the tracked closure
variables in the lambda itself will be stored. Defaults
to a global LRU cache. This cache is independent of the "compiled_cache"
used by the :class:`_engine.Connection` object.
.. seealso::
:ref:`engine_lambda_caching`
"""
return StatementLambdaElement(
lmb,
roles.StatementRole,
LambdaOptions(
enable_tracking=enable_tracking,
track_on=track_on,
track_closure_variables=track_closure_variables,
global_track_bound_values=global_track_bound_values,
track_bound_values=track_bound_values,
lambda_cache=lambda_cache,
),
)
class LambdaElement(elements.ClauseElement):
"""A SQL construct where the state is stored as an un-invoked lambda.
The :class:`_sql.LambdaElement` is produced transparently whenever
passing lambda expressions into SQL constructs, such as::
stmt = select(table).where(lambda: table.c.col == parameter)
The :class:`_sql.LambdaElement` is the base of the
:class:`_sql.StatementLambdaElement` which represents a full statement
within a lambda.
.. versionadded:: 1.4
.. seealso::
:ref:`engine_lambda_caching`
"""
__visit_name__ = "lambda_element"
_is_lambda_element = True
_traverse_internals = [
("_resolved", visitors.InternalTraversal.dp_clauseelement)
]
_transforms: Tuple[_CloneCallableType, ...] = ()
_resolved_bindparams: List[BindParameter[Any]]
parent_lambda: Optional[StatementLambdaElement] = None
closure_cache_key: Union[Tuple[Any, ...], Literal[CacheConst.NO_CACHE]]
role: Type[SQLRole]
_rec: Union[AnalyzedFunction, NonAnalyzedFunction]
fn: _AnyLambdaType
tracker_key: Tuple[CodeType, ...]
def __repr__(self):
return "%s(%r)" % (
self.__class__.__name__,
self.fn.__code__,
)
def __init__(
self,
fn: _LambdaType,
role: Type[SQLRole],
opts: Union[Type[LambdaOptions], LambdaOptions] = LambdaOptions,
apply_propagate_attrs: Optional[ClauseElement] = None,
):
self.fn = fn
self.role = role
self.tracker_key = (fn.__code__,)
self.opts = opts
if apply_propagate_attrs is None and (role is roles.StatementRole):
apply_propagate_attrs = self
rec = self._retrieve_tracker_rec(fn, apply_propagate_attrs, opts)
if apply_propagate_attrs is not None:
propagate_attrs = rec.propagate_attrs
if propagate_attrs:
apply_propagate_attrs._propagate_attrs = propagate_attrs
def _retrieve_tracker_rec(self, fn, apply_propagate_attrs, opts):
lambda_cache = opts.lambda_cache
if lambda_cache is None:
lambda_cache = _closure_per_cache_key
tracker_key = self.tracker_key
fn = self.fn
closure = fn.__closure__
tracker = AnalyzedCode.get(
fn,
self,
opts,
)
bindparams: List[BindParameter[Any]]
self._resolved_bindparams = bindparams = []
if self.parent_lambda is not None:
parent_closure_cache_key = self.parent_lambda.closure_cache_key
else:
parent_closure_cache_key = ()
cache_key: Union[Tuple[Any, ...], Literal[CacheConst.NO_CACHE]]
if parent_closure_cache_key is not _cache_key.NO_CACHE:
anon_map = visitors.anon_map()
cache_key = tuple(
[
getter(closure, opts, anon_map, bindparams)
for getter in tracker.closure_trackers
]
)
if _cache_key.NO_CACHE not in anon_map:
cache_key = parent_closure_cache_key + cache_key
self.closure_cache_key = cache_key
try:
rec = lambda_cache[tracker_key + cache_key]
except KeyError:
rec = None
else:
cache_key = _cache_key.NO_CACHE
rec = None
else:
cache_key = _cache_key.NO_CACHE
rec = None
self.closure_cache_key = cache_key
if rec is None:
if cache_key is not _cache_key.NO_CACHE:
with AnalyzedCode._generation_mutex:
key = tracker_key + cache_key
if key not in lambda_cache:
rec = AnalyzedFunction(
tracker, self, apply_propagate_attrs, fn
)
rec.closure_bindparams = bindparams
lambda_cache[key] = rec
else:
rec = lambda_cache[key]
else:
rec = NonAnalyzedFunction(self._invoke_user_fn(fn))
else:
bindparams[:] = [
orig_bind._with_value(new_bind.value, maintain_key=True)
for orig_bind, new_bind in zip(
rec.closure_bindparams, bindparams
)
]
self._rec = rec
if cache_key is not _cache_key.NO_CACHE:
if self.parent_lambda is not None:
bindparams[:0] = self.parent_lambda._resolved_bindparams
lambda_element: Optional[LambdaElement] = self
while lambda_element is not None:
rec = lambda_element._rec
if rec.bindparam_trackers:
tracker_instrumented_fn = rec.tracker_instrumented_fn
for tracker in rec.bindparam_trackers:
tracker(
lambda_element.fn,
tracker_instrumented_fn,
bindparams,
)
lambda_element = lambda_element.parent_lambda
return rec
def __getattr__(self, key):
return getattr(self._rec.expected_expr, key)
@property
def _is_sequence(self):
return self._rec.is_sequence
@property
def _select_iterable(self):
if self._is_sequence:
return itertools.chain.from_iterable(
[element._select_iterable for element in self._resolved]
)
else:
return self._resolved._select_iterable
@property
def _from_objects(self):
if self._is_sequence:
return itertools.chain.from_iterable(
[element._from_objects for element in self._resolved]
)
else:
return self._resolved._from_objects
def _param_dict(self):
return {b.key: b.value for b in self._resolved_bindparams}
def _setup_binds_for_tracked_expr(self, expr):
bindparam_lookup = {b.key: b for b in self._resolved_bindparams}
def replace(
element: Optional[visitors.ExternallyTraversible], **kw: Any
) -> Optional[visitors.ExternallyTraversible]:
if isinstance(element, elements.BindParameter):
if element.key in bindparam_lookup:
bind = bindparam_lookup[element.key]
if element.expanding:
bind.expanding = True
bind.expand_op = element.expand_op
bind.type = element.type
return bind
return None
if self._rec.is_sequence:
expr = [
visitors.replacement_traverse(sub_expr, {}, replace)
for sub_expr in expr
]
elif getattr(expr, "is_clause_element", False):
expr = visitors.replacement_traverse(expr, {}, replace)
return expr
def _copy_internals(
self,
clone: _CloneCallableType = _clone,
deferred_copy_internals: Optional[_CloneCallableType] = None,
**kw: Any,
) -> None:
# TODO: this needs A LOT of tests
self._resolved = clone(
self._resolved,
deferred_copy_internals=deferred_copy_internals,
**kw,
)
@util.memoized_property
def _resolved(self):
expr = self._rec.expected_expr
if self._resolved_bindparams:
expr = self._setup_binds_for_tracked_expr(expr)
return expr
def _gen_cache_key(self, anon_map, bindparams):
if self.closure_cache_key is _cache_key.NO_CACHE:
anon_map[_cache_key.NO_CACHE] = True
return None
cache_key = (
self.fn.__code__,
self.__class__,
) + self.closure_cache_key
parent = self.parent_lambda
while parent is not None:
assert parent.closure_cache_key is not CacheConst.NO_CACHE
parent_closure_cache_key: Tuple[Any, ...] = (
parent.closure_cache_key
)
cache_key = (
(parent.fn.__code__,) + parent_closure_cache_key + cache_key
)
parent = parent.parent_lambda
if self._resolved_bindparams:
bindparams.extend(self._resolved_bindparams)
return cache_key
def _invoke_user_fn(self, fn: _AnyLambdaType, *arg: Any) -> ClauseElement:
return fn() # type: ignore[no-any-return]
class DeferredLambdaElement(LambdaElement):
"""A LambdaElement where the lambda accepts arguments and is
invoked within the compile phase with special context.
This lambda doesn't normally produce its real SQL expression outside of the
compile phase. It is passed a fixed set of initial arguments
so that it can generate a sample expression.
"""
def __init__(
self,
fn: _AnyLambdaType,
role: Type[roles.SQLRole],
opts: Union[Type[LambdaOptions], LambdaOptions] = LambdaOptions,
lambda_args: Tuple[Any, ...] = (),
):
self.lambda_args = lambda_args
super().__init__(fn, role, opts)
def _invoke_user_fn(self, fn, *arg):
return fn(*self.lambda_args)
def _resolve_with_args(self, *lambda_args: Any) -> ClauseElement:
assert isinstance(self._rec, AnalyzedFunction)
tracker_fn = self._rec.tracker_instrumented_fn
expr = tracker_fn(*lambda_args)
expr = coercions.expect(self.role, expr)
expr = self._setup_binds_for_tracked_expr(expr)
# this validation is getting very close, but not quite, to achieving
# #5767. The problem is if the base lambda uses an unnamed column
# as is very common with mixins, the parameter name is different
# and it produces a false positive; that is, for the documented case
# that is exactly what people will be doing, it doesn't work, so
# I'm not really sure how to handle this right now.
# expected_binds = [
# b._orig_key
# for b in self._rec.expr._generate_cache_key()[1]
# if b.required
# ]
# got_binds = [
# b._orig_key for b in expr._generate_cache_key()[1] if b.required
# ]
# if expected_binds != got_binds:
# raise exc.InvalidRequestError(
# "Lambda callable at %s produced a different set of bound "
# "parameters than its original run: %s"
# % (self.fn.__code__, ", ".join(got_binds))
# )
# TODO: TEST TEST TEST, this is very out there
for deferred_copy_internals in self._transforms:
expr = deferred_copy_internals(expr)
return expr # type: ignore
def _copy_internals(
self, clone=_clone, deferred_copy_internals=None, **kw
):
super()._copy_internals(
clone=clone,
deferred_copy_internals=deferred_copy_internals, # **kw
opts=kw,
)
# TODO: A LOT A LOT of tests. for _resolve_with_args, we don't know
# our expression yet. so hold onto the replacement
if deferred_copy_internals:
self._transforms += (deferred_copy_internals,)
class StatementLambdaElement(
roles.AllowsLambdaRole, LambdaElement, Executable
):
"""Represent a composable SQL statement as a :class:`_sql.LambdaElement`.
The :class:`_sql.StatementLambdaElement` is constructed using the
:func:`_sql.lambda_stmt` function::
from sqlalchemy import lambda_stmt
stmt = lambda_stmt(lambda: select(table))
Once constructed, additional criteria can be built onto the statement
by adding subsequent lambdas, which accept the existing statement
object as a single parameter::
stmt += lambda s: s.where(table.c.col == parameter)
.. versionadded:: 1.4
.. seealso::
:ref:`engine_lambda_caching`
"""
if TYPE_CHECKING:
def __init__(
self,
fn: _StmtLambdaType,
role: Type[SQLRole],
opts: Union[Type[LambdaOptions], LambdaOptions] = LambdaOptions,
apply_propagate_attrs: Optional[ClauseElement] = None,
): ...
def __add__(
self, other: _StmtLambdaElementType[Any]
) -> StatementLambdaElement:
return self.add_criteria(other)
def add_criteria(
self,
other: _StmtLambdaElementType[Any],
enable_tracking: bool = True,
track_on: Optional[Any] = None,
track_closure_variables: bool = True,
track_bound_values: bool = True,
) -> StatementLambdaElement:
"""Add new criteria to this :class:`_sql.StatementLambdaElement`.
E.g.::
>>> def my_stmt(parameter):
... stmt = lambda_stmt(
... lambda: select(table.c.x, table.c.y),
... )
... stmt = stmt.add_criteria(
... lambda: table.c.x > parameter
... )
... return stmt
The :meth:`_sql.StatementLambdaElement.add_criteria` method is
equivalent to using the Python addition operator to add a new
lambda, except that additional arguments may be added including
``track_closure_values`` and ``track_on``::
>>> def my_stmt(self, foo):
... stmt = lambda_stmt(
... lambda: select(func.max(foo.x, foo.y)),
... track_closure_variables=False
... )
... stmt = stmt.add_criteria(
... lambda: self.where_criteria,
... track_on=[self]
... )
... return stmt
See :func:`_sql.lambda_stmt` for a description of the parameters
accepted.
"""
opts = self.opts + dict(
enable_tracking=enable_tracking,
track_closure_variables=track_closure_variables,
global_track_bound_values=self.opts.global_track_bound_values,
track_on=track_on,
track_bound_values=track_bound_values,
)
return LinkedLambdaElement(other, parent_lambda=self, opts=opts)
def _execute_on_connection(
self, connection, distilled_params, execution_options
):
if TYPE_CHECKING:
assert isinstance(self._rec.expected_expr, ClauseElement)
if self._rec.expected_expr.supports_execution:
return connection._execute_clauseelement(
self, distilled_params, execution_options
)
else:
raise exc.ObjectNotExecutableError(self)
@property
def _proxied(self) -> Any:
return self._rec_expected_expr
@property
def _with_options(self):
return self._proxied._with_options
@property
def _effective_plugin_target(self):
return self._proxied._effective_plugin_target
@property
def _execution_options(self):
return self._proxied._execution_options
@property
def _all_selected_columns(self):
return self._proxied._all_selected_columns
@property
def is_select(self):
return self._proxied.is_select
@property
def is_update(self):
return self._proxied.is_update
@property
def is_insert(self):
return self._proxied.is_insert
@property
def is_text(self):
return self._proxied.is_text
@property
def is_delete(self):
return self._proxied.is_delete
@property
def is_dml(self):
return self._proxied.is_dml
def spoil(self) -> NullLambdaStatement:
"""Return a new :class:`.StatementLambdaElement` that will run
all lambdas unconditionally each time.
"""
return NullLambdaStatement(self.fn())
class NullLambdaStatement(roles.AllowsLambdaRole, elements.ClauseElement):
"""Provides the :class:`.StatementLambdaElement` API but does not
cache or analyze lambdas.
the lambdas are instead invoked immediately.
The intended use is to isolate issues that may arise when using
lambda statements.
"""
__visit_name__ = "lambda_element"
_is_lambda_element = True
_traverse_internals = [
("_resolved", visitors.InternalTraversal.dp_clauseelement)
]
def __init__(self, statement):
self._resolved = statement
self._propagate_attrs = statement._propagate_attrs
def __getattr__(self, key):
return getattr(self._resolved, key)
def __add__(self, other):
statement = other(self._resolved)
return NullLambdaStatement(statement)
def add_criteria(self, other, **kw):
statement = other(self._resolved)
return NullLambdaStatement(statement)
def _execute_on_connection(
self, connection, distilled_params, execution_options
):
if self._resolved.supports_execution:
return connection._execute_clauseelement(
self, distilled_params, execution_options
)
else:
raise exc.ObjectNotExecutableError(self)
class LinkedLambdaElement(StatementLambdaElement):
"""Represent subsequent links of a :class:`.StatementLambdaElement`."""
parent_lambda: StatementLambdaElement
def __init__(
self,
fn: _StmtLambdaElementType[Any],
parent_lambda: StatementLambdaElement,
opts: Union[Type[LambdaOptions], LambdaOptions],
):
self.opts = opts
self.fn = fn
self.parent_lambda = parent_lambda
self.tracker_key = parent_lambda.tracker_key + (fn.__code__,)
self._retrieve_tracker_rec(fn, self, opts)
self._propagate_attrs = parent_lambda._propagate_attrs
def _invoke_user_fn(self, fn, *arg):
return fn(self.parent_lambda._resolved)
class AnalyzedCode:
__slots__ = (
"track_closure_variables",
"track_bound_values",
"bindparam_trackers",
"closure_trackers",
"build_py_wrappers",
)
_fns: weakref.WeakKeyDictionary[CodeType, AnalyzedCode] = (
weakref.WeakKeyDictionary()
)
_generation_mutex = threading.RLock()
@classmethod
def get(cls, fn, lambda_element, lambda_kw, **kw):
try:
# TODO: validate kw haven't changed?
return cls._fns[fn.__code__]
except KeyError:
pass
with cls._generation_mutex:
# check for other thread already created object
if fn.__code__ in cls._fns:
return cls._fns[fn.__code__]
analyzed: AnalyzedCode
cls._fns[fn.__code__] = analyzed = AnalyzedCode(
fn, lambda_element, lambda_kw, **kw
)
return analyzed
def __init__(self, fn, lambda_element, opts):
if inspect.ismethod(fn):
raise exc.ArgumentError(
"Method %s may not be passed as a SQL expression" % fn
)
closure = fn.__closure__
self.track_bound_values = (
opts.track_bound_values and opts.global_track_bound_values
)
enable_tracking = opts.enable_tracking
track_on = opts.track_on
track_closure_variables = opts.track_closure_variables
self.track_closure_variables = track_closure_variables and not track_on
# a list of callables generated from _bound_parameter_getter_*
# functions. Each of these uses a PyWrapper object to retrieve
# a parameter value
self.bindparam_trackers = []
# a list of callables generated from _cache_key_getter_* functions
# these callables work to generate a cache key for the lambda
# based on what's inside its closure variables.
self.closure_trackers = []
self.build_py_wrappers = []
if enable_tracking:
if track_on:
self._init_track_on(track_on)
self._init_globals(fn)
if closure:
self._init_closure(fn)
self._setup_additional_closure_trackers(fn, lambda_element, opts)
def _init_track_on(self, track_on):
self.closure_trackers.extend(
self._cache_key_getter_track_on(idx, elem)
for idx, elem in enumerate(track_on)
)
def _init_globals(self, fn):
build_py_wrappers = self.build_py_wrappers
bindparam_trackers = self.bindparam_trackers
track_bound_values = self.track_bound_values
for name in fn.__code__.co_names:
if name not in fn.__globals__:
continue
_bound_value = self._roll_down_to_literal(fn.__globals__[name])
if coercions._deep_is_literal(_bound_value):
build_py_wrappers.append((name, None))
if track_bound_values:
bindparam_trackers.append(
self._bound_parameter_getter_func_globals(name)
)
def _init_closure(self, fn):
build_py_wrappers = self.build_py_wrappers
closure = fn.__closure__
track_bound_values = self.track_bound_values
track_closure_variables = self.track_closure_variables
bindparam_trackers = self.bindparam_trackers
closure_trackers = self.closure_trackers
for closure_index, (fv, cell) in enumerate(
zip(fn.__code__.co_freevars, closure)
):
_bound_value = self._roll_down_to_literal(cell.cell_contents)
if coercions._deep_is_literal(_bound_value):
build_py_wrappers.append((fv, closure_index))
if track_bound_values:
bindparam_trackers.append(
self._bound_parameter_getter_func_closure(
fv, closure_index
)
)
else:
# for normal cell contents, add them to a list that
# we can compare later when we get new lambdas. if
# any identities have changed, then we will
# recalculate the whole lambda and run it again.
if track_closure_variables:
closure_trackers.append(
self._cache_key_getter_closure_variable(
fn, fv, closure_index, cell.cell_contents
)
)
def _setup_additional_closure_trackers(self, fn, lambda_element, opts):
# an additional step is to actually run the function, then
# go through the PyWrapper objects that were set up to catch a bound
# parameter. then if they *didn't* make a param, oh they're another
# object in the closure we have to track for our cache key. so
# create trackers to catch those.
analyzed_function = AnalyzedFunction(
self,
lambda_element,
None,
fn,
)
closure_trackers = self.closure_trackers
for pywrapper in analyzed_function.closure_pywrappers:
if not pywrapper._sa__has_param:
closure_trackers.append(
self._cache_key_getter_tracked_literal(fn, pywrapper)
)
@classmethod
def _roll_down_to_literal(cls, element):
is_clause_element = hasattr(element, "__clause_element__")
if is_clause_element:
while not isinstance(
element, (elements.ClauseElement, schema.SchemaItem, type)
):
try:
element = element.__clause_element__()
except AttributeError:
break
if not is_clause_element:
insp = inspection.inspect(element, raiseerr=False)
if insp is not None:
try:
return insp.__clause_element__()
except AttributeError:
return insp
# TODO: should we coerce consts None/True/False here?
return element
else:
return element
def _bound_parameter_getter_func_globals(self, name):
"""Return a getter that will extend a list of bound parameters
with new entries from the ``__globals__`` collection of a particular
lambda.
"""
def extract_parameter_value(
current_fn, tracker_instrumented_fn, result
):
wrapper = tracker_instrumented_fn.__globals__[name]
object.__getattribute__(wrapper, "_extract_bound_parameters")(
current_fn.__globals__[name], result
)
return extract_parameter_value
def _bound_parameter_getter_func_closure(self, name, closure_index):
"""Return a getter that will extend a list of bound parameters
with new entries from the ``__closure__`` collection of a particular
lambda.
"""
def extract_parameter_value(
current_fn, tracker_instrumented_fn, result
):
wrapper = tracker_instrumented_fn.__closure__[
closure_index
].cell_contents
object.__getattribute__(wrapper, "_extract_bound_parameters")(
current_fn.__closure__[closure_index].cell_contents, result
)
return extract_parameter_value
def _cache_key_getter_track_on(self, idx, elem):
"""Return a getter that will extend a cache key with new entries
from the "track_on" parameter passed to a :class:`.LambdaElement`.
"""
if isinstance(elem, tuple):
# tuple must contain hascachekey elements
def get(closure, opts, anon_map, bindparams):
return tuple(
tup_elem._gen_cache_key(anon_map, bindparams)
for tup_elem in opts.track_on[idx]
)
elif isinstance(elem, _cache_key.HasCacheKey):
def get(closure, opts, anon_map, bindparams):
return opts.track_on[idx]._gen_cache_key(anon_map, bindparams)
else:
def get(closure, opts, anon_map, bindparams):
return opts.track_on[idx]
return get
def _cache_key_getter_closure_variable(
self,
fn,
variable_name,
idx,
cell_contents,
use_clause_element=False,
use_inspect=False,
):
"""Return a getter that will extend a cache key with new entries
from the ``__closure__`` collection of a particular lambda.
"""
if isinstance(cell_contents, _cache_key.HasCacheKey):
def get(closure, opts, anon_map, bindparams):
obj = closure[idx].cell_contents
if use_inspect:
obj = inspection.inspect(obj)
elif use_clause_element:
while hasattr(obj, "__clause_element__"):
if not getattr(obj, "is_clause_element", False):
obj = obj.__clause_element__()
return obj._gen_cache_key(anon_map, bindparams)
elif isinstance(cell_contents, types.FunctionType):
def get(closure, opts, anon_map, bindparams):
return closure[idx].cell_contents.__code__
elif isinstance(cell_contents, collections_abc.Sequence):
def get(closure, opts, anon_map, bindparams):
contents = closure[idx].cell_contents
try:
return tuple(
elem._gen_cache_key(anon_map, bindparams)
for elem in contents
)
except AttributeError as ae:
self._raise_for_uncacheable_closure_variable(
variable_name, fn, from_=ae
)
else:
# if the object is a mapped class or aliased class, or some
# other object in the ORM realm of things like that, imitate
# the logic used in coercions.expect() to roll it down to the
# SQL element
element = cell_contents
is_clause_element = False
while hasattr(element, "__clause_element__"):
is_clause_element = True
if not getattr(element, "is_clause_element", False):
element = element.__clause_element__()
else:
break
if not is_clause_element:
insp = inspection.inspect(element, raiseerr=False)
if insp is not None:
return self._cache_key_getter_closure_variable(
fn, variable_name, idx, insp, use_inspect=True
)
else:
return self._cache_key_getter_closure_variable(
fn, variable_name, idx, element, use_clause_element=True
)
self._raise_for_uncacheable_closure_variable(variable_name, fn)
return get
def _raise_for_uncacheable_closure_variable(
self, variable_name, fn, from_=None
):
raise exc.InvalidRequestError(
"Closure variable named '%s' inside of lambda callable %s "
"does not refer to a cacheable SQL element, and also does not "
"appear to be serving as a SQL literal bound value based on "
"the default "
"SQL expression returned by the function. This variable "
"needs to remain outside the scope of a SQL-generating lambda "
"so that a proper cache key may be generated from the "
"lambda's state. Evaluate this variable outside of the "
"lambda, set track_on=[<elements>] to explicitly select "
"closure elements to track, or set "
"track_closure_variables=False to exclude "
"closure variables from being part of the cache key."
% (variable_name, fn.__code__),
) from from_
def _cache_key_getter_tracked_literal(self, fn, pytracker):
"""Return a getter that will extend a cache key with new entries
from the ``__closure__`` collection of a particular lambda.
this getter differs from _cache_key_getter_closure_variable
in that these are detected after the function is run, and PyWrapper
objects have recorded that a particular literal value is in fact
not being interpreted as a bound parameter.
"""
elem = pytracker._sa__to_evaluate
closure_index = pytracker._sa__closure_index
variable_name = pytracker._sa__name
return self._cache_key_getter_closure_variable(
fn, variable_name, closure_index, elem
)
class NonAnalyzedFunction:
__slots__ = ("expr",)
closure_bindparams: Optional[List[BindParameter[Any]]] = None
bindparam_trackers: Optional[List[_BoundParameterGetter]] = None
is_sequence = False
expr: ClauseElement
def __init__(self, expr: ClauseElement):
self.expr = expr
@property
def expected_expr(self) -> ClauseElement:
return self.expr
class AnalyzedFunction:
__slots__ = (
"analyzed_code",
"fn",
"closure_pywrappers",
"tracker_instrumented_fn",
"expr",
"bindparam_trackers",
"expected_expr",
"is_sequence",
"propagate_attrs",
"closure_bindparams",
)
closure_bindparams: Optional[List[BindParameter[Any]]]
expected_expr: Union[ClauseElement, List[ClauseElement]]
bindparam_trackers: Optional[List[_BoundParameterGetter]]
def __init__(
self,
analyzed_code,
lambda_element,
apply_propagate_attrs,
fn,
):
self.analyzed_code = analyzed_code
self.fn = fn
self.bindparam_trackers = analyzed_code.bindparam_trackers
self._instrument_and_run_function(lambda_element)
self._coerce_expression(lambda_element, apply_propagate_attrs)
def _instrument_and_run_function(self, lambda_element):
analyzed_code = self.analyzed_code
fn = self.fn
self.closure_pywrappers = closure_pywrappers = []
build_py_wrappers = analyzed_code.build_py_wrappers
if not build_py_wrappers:
self.tracker_instrumented_fn = tracker_instrumented_fn = fn
self.expr = lambda_element._invoke_user_fn(tracker_instrumented_fn)
else:
track_closure_variables = analyzed_code.track_closure_variables
closure = fn.__closure__
# will form the __closure__ of the function when we rebuild it
if closure:
new_closure = {
fv: cell.cell_contents
for fv, cell in zip(fn.__code__.co_freevars, closure)
}
else:
new_closure = {}
# will form the __globals__ of the function when we rebuild it
new_globals = fn.__globals__.copy()
for name, closure_index in build_py_wrappers:
if closure_index is not None:
value = closure[closure_index].cell_contents
new_closure[name] = bind = PyWrapper(
fn,
name,
value,
closure_index=closure_index,
track_bound_values=(
self.analyzed_code.track_bound_values
),
)
if track_closure_variables:
closure_pywrappers.append(bind)
else:
value = fn.__globals__[name]
new_globals[name] = bind = PyWrapper(fn, name, value)
# rewrite the original fn. things that look like they will
# become bound parameters are wrapped in a PyWrapper.
self.tracker_instrumented_fn = tracker_instrumented_fn = (
self._rewrite_code_obj(
fn,
[new_closure[name] for name in fn.__code__.co_freevars],
new_globals,
)
)
# now invoke the function. This will give us a new SQL
# expression, but all the places that there would be a bound
# parameter, the PyWrapper in its place will give us a bind
# with a predictable name we can match up later.
# additionally, each PyWrapper will log that it did in fact
# create a parameter, otherwise, it's some kind of Python
# object in the closure and we want to track that, to make
# sure it doesn't change to something else, or if it does,
# that we create a different tracked function with that
# variable.
self.expr = lambda_element._invoke_user_fn(tracker_instrumented_fn)
def _coerce_expression(self, lambda_element, apply_propagate_attrs):
"""Run the tracker-generated expression through coercion rules.
After the user-defined lambda has been invoked to produce a statement
for re-use, run it through coercion rules to both check that it's the
correct type of object and also to coerce it to its useful form.
"""
parent_lambda = lambda_element.parent_lambda
expr = self.expr
if parent_lambda is None:
if isinstance(expr, collections_abc.Sequence):
self.expected_expr = [
cast(
"ClauseElement",
coercions.expect(
lambda_element.role,
sub_expr,
apply_propagate_attrs=apply_propagate_attrs,
),
)
for sub_expr in expr
]
self.is_sequence = True
else:
self.expected_expr = cast(
"ClauseElement",
coercions.expect(
lambda_element.role,
expr,
apply_propagate_attrs=apply_propagate_attrs,
),
)
self.is_sequence = False
else:
self.expected_expr = expr
self.is_sequence = False
if apply_propagate_attrs is not None:
self.propagate_attrs = apply_propagate_attrs._propagate_attrs
else:
self.propagate_attrs = util.EMPTY_DICT
def _rewrite_code_obj(self, f, cell_values, globals_):
"""Return a copy of f, with a new closure and new globals
yes it works in pypy :P
"""
argrange = range(len(cell_values))
code = "def make_cells():\n"
if cell_values:
code += " (%s) = (%s)\n" % (
", ".join("i%d" % i for i in argrange),
", ".join("o%d" % i for i in argrange),
)
code += " def closure():\n"
code += " return %s\n" % ", ".join("i%d" % i for i in argrange)
code += " return closure.__closure__"
vars_ = {"o%d" % i: cell_values[i] for i in argrange}
exec(code, vars_, vars_)
closure = vars_["make_cells"]()
func = type(f)(
f.__code__, globals_, f.__name__, f.__defaults__, closure
)
func.__annotations__ = f.__annotations__
func.__kwdefaults__ = f.__kwdefaults__
func.__doc__ = f.__doc__
func.__module__ = f.__module__
return func
class PyWrapper(ColumnOperators):
"""A wrapper object that is injected into the ``__globals__`` and
``__closure__`` of a Python function.
When the function is instrumented with :class:`.PyWrapper` objects, it is
then invoked just once in order to set up the wrappers. We look through
all the :class:`.PyWrapper` objects we made to find the ones that generated
a :class:`.BindParameter` object, e.g. the expression system interpreted
something as a literal. Those positions in the globals/closure are then
ones that we will look at, each time a new lambda comes in that refers to
the same ``__code__`` object. In this way, we keep a single version of
the SQL expression that this lambda produced, without calling upon the
Python function that created it more than once, unless its other closure
variables have changed. The expression is then transformed to have the
new bound values embedded into it.
"""
def __init__(
self,
fn,
name,
to_evaluate,
closure_index=None,
getter=None,
track_bound_values=True,
):
self.fn = fn
self._name = name
self._to_evaluate = to_evaluate
self._param = None
self._has_param = False
self._bind_paths = {}
self._getter = getter
self._closure_index = closure_index
self.track_bound_values = track_bound_values
def __call__(self, *arg, **kw):
elem = object.__getattribute__(self, "_to_evaluate")
value = elem(*arg, **kw)
if (
self._sa_track_bound_values
and coercions._deep_is_literal(value)
and not isinstance(
# TODO: coverage where an ORM option or similar is here
value,
_cache_key.HasCacheKey,
)
):
name = object.__getattribute__(self, "_name")
raise exc.InvalidRequestError(
"Can't invoke Python callable %s() inside of lambda "
"expression argument at %s; lambda SQL constructs should "
"not invoke functions from closure variables to produce "
"literal values since the "
"lambda SQL system normally extracts bound values without "
"actually "
"invoking the lambda or any functions within it. Call the "
"function outside of the "
"lambda and assign to a local variable that is used in the "
"lambda as a closure variable, or set "
"track_bound_values=False if the return value of this "
"function is used in some other way other than a SQL bound "
"value." % (name, self._sa_fn.__code__)
)
else:
return value
def operate(self, op, *other, **kwargs):
elem = object.__getattribute__(self, "_py_wrapper_literal")()
return op(elem, *other, **kwargs)
def reverse_operate(self, op, other, **kwargs):
elem = object.__getattribute__(self, "_py_wrapper_literal")()
return op(other, elem, **kwargs)
def _extract_bound_parameters(self, starting_point, result_list):
param = object.__getattribute__(self, "_param")
if param is not None:
param = param._with_value(starting_point, maintain_key=True)
result_list.append(param)
for pywrapper in object.__getattribute__(self, "_bind_paths").values():
getter = object.__getattribute__(pywrapper, "_getter")
element = getter(starting_point)
pywrapper._sa__extract_bound_parameters(element, result_list)
def _py_wrapper_literal(self, expr=None, operator=None, **kw):
param = object.__getattribute__(self, "_param")
to_evaluate = object.__getattribute__(self, "_to_evaluate")
if param is None:
name = object.__getattribute__(self, "_name")
self._param = param = elements.BindParameter(
name,
required=False,
unique=True,
_compared_to_operator=operator,
_compared_to_type=expr.type if expr is not None else None,
)
self._has_param = True
return param._with_value(to_evaluate, maintain_key=True)
def __bool__(self):
to_evaluate = object.__getattribute__(self, "_to_evaluate")
return bool(to_evaluate)
def __getattribute__(self, key):
if key.startswith("_sa_"):
return object.__getattribute__(self, key[4:])
elif key in (
"__clause_element__",
"operate",
"reverse_operate",
"_py_wrapper_literal",
"__class__",
"__dict__",
):
return object.__getattribute__(self, key)
if key.startswith("__"):
elem = object.__getattribute__(self, "_to_evaluate")
return getattr(elem, key)
else:
return self._sa__add_getter(key, operator.attrgetter)
def __iter__(self):
elem = object.__getattribute__(self, "_to_evaluate")
return iter(elem)
def __getitem__(self, key):
elem = object.__getattribute__(self, "_to_evaluate")
if not hasattr(elem, "__getitem__"):
raise AttributeError("__getitem__")
if isinstance(key, PyWrapper):
# TODO: coverage
raise exc.InvalidRequestError(
"Dictionary keys / list indexes inside of a cached "
"lambda must be Python literals only"
)
return self._sa__add_getter(key, operator.itemgetter)
def _add_getter(self, key, getter_fn):
bind_paths = object.__getattribute__(self, "_bind_paths")
bind_path_key = (key, getter_fn)
if bind_path_key in bind_paths:
return bind_paths[bind_path_key]
getter = getter_fn(key)
elem = object.__getattribute__(self, "_to_evaluate")
value = getter(elem)
rolled_down_value = AnalyzedCode._roll_down_to_literal(value)
if coercions._deep_is_literal(rolled_down_value):
wrapper = PyWrapper(self._sa_fn, key, value, getter=getter)
bind_paths[bind_path_key] = wrapper
return wrapper
else:
return value
@inspection._inspects(LambdaElement)
def insp(lmb):
return inspection.inspect(lmb._resolved)
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