525 lines
17 KiB
Python
525 lines
17 KiB
Python
import inspect
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from copy import copy
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from django.conf import settings
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from django.utils import timezone
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from django.utils.functional import cached_property
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from django.utils.six.moves import range
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from .query_utils import QueryWrapper
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class RegisterLookupMixin(object):
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def _get_lookup(self, lookup_name):
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try:
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return self.class_lookups[lookup_name]
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except KeyError:
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# To allow for inheritance, check parent class' class_lookups.
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for parent in inspect.getmro(self.__class__):
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if 'class_lookups' not in parent.__dict__:
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continue
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if lookup_name in parent.class_lookups:
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return parent.class_lookups[lookup_name]
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except AttributeError:
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# This class didn't have any class_lookups
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pass
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return None
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def get_lookup(self, lookup_name):
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found = self._get_lookup(lookup_name)
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if found is None and hasattr(self, 'output_field'):
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return self.output_field.get_lookup(lookup_name)
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if found is not None and not issubclass(found, Lookup):
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return None
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return found
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def get_transform(self, lookup_name):
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found = self._get_lookup(lookup_name)
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if found is None and hasattr(self, 'output_field'):
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return self.output_field.get_transform(lookup_name)
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if found is not None and not issubclass(found, Transform):
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return None
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return found
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@classmethod
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def register_lookup(cls, lookup):
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if 'class_lookups' not in cls.__dict__:
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cls.class_lookups = {}
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cls.class_lookups[lookup.lookup_name] = lookup
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return lookup
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@classmethod
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def _unregister_lookup(cls, lookup):
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"""
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Removes given lookup from cls lookups. Meant to be used in
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tests only.
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"""
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del cls.class_lookups[lookup.lookup_name]
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class Transform(RegisterLookupMixin):
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bilateral = False
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def __init__(self, lhs, lookups):
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self.lhs = lhs
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self.init_lookups = lookups[:]
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def as_sql(self, compiler, connection):
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raise NotImplementedError
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@cached_property
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def output_field(self):
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return self.lhs.output_field
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def relabeled_clone(self, relabels):
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return self.__class__(self.lhs.relabeled_clone(relabels))
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def get_group_by_cols(self):
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return self.lhs.get_group_by_cols()
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def get_bilateral_transforms(self):
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if hasattr(self.lhs, 'get_bilateral_transforms'):
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bilateral_transforms = self.lhs.get_bilateral_transforms()
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else:
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bilateral_transforms = []
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if self.bilateral:
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bilateral_transforms.append((self.__class__, self.init_lookups))
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return bilateral_transforms
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@cached_property
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def contains_aggregate(self):
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return self.lhs.contains_aggregate
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class Lookup(RegisterLookupMixin):
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lookup_name = None
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def __init__(self, lhs, rhs):
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self.lhs, self.rhs = lhs, rhs
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self.rhs = self.get_prep_lookup()
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if hasattr(self.lhs, 'get_bilateral_transforms'):
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bilateral_transforms = self.lhs.get_bilateral_transforms()
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else:
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bilateral_transforms = []
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if bilateral_transforms:
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# We should warn the user as soon as possible if he is trying to apply
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# a bilateral transformation on a nested QuerySet: that won't work.
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# We need to import QuerySet here so as to avoid circular
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from django.db.models.query import QuerySet
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if isinstance(rhs, QuerySet):
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raise NotImplementedError("Bilateral transformations on nested querysets are not supported.")
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self.bilateral_transforms = bilateral_transforms
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def apply_bilateral_transforms(self, value):
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for transform, lookups in self.bilateral_transforms:
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value = transform(value, lookups)
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return value
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def batch_process_rhs(self, compiler, connection, rhs=None):
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if rhs is None:
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rhs = self.rhs
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if self.bilateral_transforms:
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sqls, sqls_params = [], []
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for p in rhs:
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value = QueryWrapper('%s',
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[self.lhs.output_field.get_db_prep_value(p, connection)])
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value = self.apply_bilateral_transforms(value)
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sql, sql_params = compiler.compile(value)
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sqls.append(sql)
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sqls_params.extend(sql_params)
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else:
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params = self.lhs.output_field.get_db_prep_lookup(
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self.lookup_name, rhs, connection, prepared=True)
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sqls, sqls_params = ['%s'] * len(params), params
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return sqls, sqls_params
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def get_prep_lookup(self):
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return self.lhs.output_field.get_prep_lookup(self.lookup_name, self.rhs)
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def get_db_prep_lookup(self, value, connection):
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return (
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'%s', self.lhs.output_field.get_db_prep_lookup(
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self.lookup_name, value, connection, prepared=True))
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def process_lhs(self, compiler, connection, lhs=None):
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lhs = lhs or self.lhs
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return compiler.compile(lhs)
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def process_rhs(self, compiler, connection):
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value = self.rhs
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if self.bilateral_transforms:
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if self.rhs_is_direct_value():
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# Do not call get_db_prep_lookup here as the value will be
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# transformed before being used for lookup
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value = QueryWrapper("%s",
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[self.lhs.output_field.get_db_prep_value(value, connection)])
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value = self.apply_bilateral_transforms(value)
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# Due to historical reasons there are a couple of different
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# ways to produce sql here. get_compiler is likely a Query
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# instance, _as_sql QuerySet and as_sql just something with
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# as_sql. Finally the value can of course be just plain
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# Python value.
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if hasattr(value, 'get_compiler'):
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value = value.get_compiler(connection=connection)
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if hasattr(value, 'as_sql'):
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sql, params = compiler.compile(value)
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return '(' + sql + ')', params
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if hasattr(value, '_as_sql'):
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sql, params = value._as_sql(connection=connection)
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return '(' + sql + ')', params
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else:
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return self.get_db_prep_lookup(value, connection)
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def rhs_is_direct_value(self):
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return not(
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hasattr(self.rhs, 'as_sql') or
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hasattr(self.rhs, '_as_sql') or
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hasattr(self.rhs, 'get_compiler'))
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def relabeled_clone(self, relabels):
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new = copy(self)
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new.lhs = new.lhs.relabeled_clone(relabels)
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if hasattr(new.rhs, 'relabeled_clone'):
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new.rhs = new.rhs.relabeled_clone(relabels)
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return new
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def get_group_by_cols(self):
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cols = self.lhs.get_group_by_cols()
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if hasattr(self.rhs, 'get_group_by_cols'):
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cols.extend(self.rhs.get_group_by_cols())
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return cols
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def as_sql(self, compiler, connection):
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raise NotImplementedError
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@cached_property
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def contains_aggregate(self):
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return self.lhs.contains_aggregate or getattr(self.rhs, 'contains_aggregate', False)
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class BuiltinLookup(Lookup):
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def process_lhs(self, compiler, connection, lhs=None):
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lhs_sql, params = super(BuiltinLookup, self).process_lhs(
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compiler, connection, lhs)
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field_internal_type = self.lhs.output_field.get_internal_type()
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db_type = self.lhs.output_field.db_type(connection=connection)
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lhs_sql = connection.ops.field_cast_sql(
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db_type, field_internal_type) % lhs_sql
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lhs_sql = connection.ops.lookup_cast(self.lookup_name, field_internal_type) % lhs_sql
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return lhs_sql, params
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def as_sql(self, compiler, connection):
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lhs_sql, params = self.process_lhs(compiler, connection)
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rhs_sql, rhs_params = self.process_rhs(compiler, connection)
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params.extend(rhs_params)
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rhs_sql = self.get_rhs_op(connection, rhs_sql)
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return '%s %s' % (lhs_sql, rhs_sql), params
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def get_rhs_op(self, connection, rhs):
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return connection.operators[self.lookup_name] % rhs
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default_lookups = {}
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class Exact(BuiltinLookup):
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lookup_name = 'exact'
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default_lookups['exact'] = Exact
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class IExact(BuiltinLookup):
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lookup_name = 'iexact'
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def process_rhs(self, qn, connection):
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rhs, params = super(IExact, self).process_rhs(qn, connection)
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if params:
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params[0] = connection.ops.prep_for_iexact_query(params[0])
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return rhs, params
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default_lookups['iexact'] = IExact
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class GreaterThan(BuiltinLookup):
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lookup_name = 'gt'
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default_lookups['gt'] = GreaterThan
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class GreaterThanOrEqual(BuiltinLookup):
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lookup_name = 'gte'
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default_lookups['gte'] = GreaterThanOrEqual
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class LessThan(BuiltinLookup):
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lookup_name = 'lt'
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default_lookups['lt'] = LessThan
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class LessThanOrEqual(BuiltinLookup):
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lookup_name = 'lte'
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default_lookups['lte'] = LessThanOrEqual
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class In(BuiltinLookup):
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lookup_name = 'in'
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def process_rhs(self, compiler, connection):
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if self.rhs_is_direct_value():
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# rhs should be an iterable, we use batch_process_rhs
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# to prepare/transform those values
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rhs = list(self.rhs)
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if not rhs:
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from django.db.models.sql.datastructures import EmptyResultSet
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raise EmptyResultSet
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sqls, sqls_params = self.batch_process_rhs(compiler, connection, rhs)
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placeholder = '(' + ', '.join(sqls) + ')'
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return (placeholder, sqls_params)
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else:
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return super(In, self).process_rhs(compiler, connection)
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def get_rhs_op(self, connection, rhs):
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return 'IN %s' % rhs
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def as_sql(self, compiler, connection):
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max_in_list_size = connection.ops.max_in_list_size()
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if self.rhs_is_direct_value() and (max_in_list_size and
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len(self.rhs) > max_in_list_size):
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# This is a special case for Oracle which limits the number of elements
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# which can appear in an 'IN' clause.
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lhs, lhs_params = self.process_lhs(compiler, connection)
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rhs, rhs_params = self.batch_process_rhs(compiler, connection)
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in_clause_elements = ['(']
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params = []
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for offset in range(0, len(rhs_params), max_in_list_size):
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if offset > 0:
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in_clause_elements.append(' OR ')
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in_clause_elements.append('%s IN (' % lhs)
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params.extend(lhs_params)
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sqls = rhs[offset: offset + max_in_list_size]
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sqls_params = rhs_params[offset: offset + max_in_list_size]
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param_group = ', '.join(sqls)
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in_clause_elements.append(param_group)
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in_clause_elements.append(')')
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params.extend(sqls_params)
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in_clause_elements.append(')')
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return ''.join(in_clause_elements), params
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else:
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return super(In, self).as_sql(compiler, connection)
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default_lookups['in'] = In
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class PatternLookup(BuiltinLookup):
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def get_rhs_op(self, connection, rhs):
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# Assume we are in startswith. We need to produce SQL like:
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# col LIKE %s, ['thevalue%']
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# For python values we can (and should) do that directly in Python,
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# but if the value is for example reference to other column, then
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# we need to add the % pattern match to the lookup by something like
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# col LIKE othercol || '%%'
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# So, for Python values we don't need any special pattern, but for
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# SQL reference values or SQL transformations we need the correct
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# pattern added.
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if (hasattr(self.rhs, 'get_compiler') or hasattr(self.rhs, 'as_sql')
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or hasattr(self.rhs, '_as_sql') or self.bilateral_transforms):
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pattern = connection.pattern_ops[self.lookup_name].format(connection.pattern_esc)
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return pattern.format(rhs)
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else:
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return super(PatternLookup, self).get_rhs_op(connection, rhs)
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class Contains(PatternLookup):
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lookup_name = 'contains'
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def process_rhs(self, qn, connection):
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rhs, params = super(Contains, self).process_rhs(qn, connection)
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if params and not self.bilateral_transforms:
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params[0] = "%%%s%%" % connection.ops.prep_for_like_query(params[0])
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return rhs, params
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default_lookups['contains'] = Contains
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class IContains(Contains):
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lookup_name = 'icontains'
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default_lookups['icontains'] = IContains
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class StartsWith(PatternLookup):
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lookup_name = 'startswith'
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def process_rhs(self, qn, connection):
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rhs, params = super(StartsWith, self).process_rhs(qn, connection)
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if params and not self.bilateral_transforms:
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params[0] = "%s%%" % connection.ops.prep_for_like_query(params[0])
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return rhs, params
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default_lookups['startswith'] = StartsWith
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class IStartsWith(PatternLookup):
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lookup_name = 'istartswith'
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def process_rhs(self, qn, connection):
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rhs, params = super(IStartsWith, self).process_rhs(qn, connection)
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if params and not self.bilateral_transforms:
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params[0] = "%s%%" % connection.ops.prep_for_like_query(params[0])
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return rhs, params
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default_lookups['istartswith'] = IStartsWith
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class EndsWith(PatternLookup):
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lookup_name = 'endswith'
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def process_rhs(self, qn, connection):
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rhs, params = super(EndsWith, self).process_rhs(qn, connection)
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if params and not self.bilateral_transforms:
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params[0] = "%%%s" % connection.ops.prep_for_like_query(params[0])
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return rhs, params
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default_lookups['endswith'] = EndsWith
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class IEndsWith(PatternLookup):
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lookup_name = 'iendswith'
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def process_rhs(self, qn, connection):
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rhs, params = super(IEndsWith, self).process_rhs(qn, connection)
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if params and not self.bilateral_transforms:
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params[0] = "%%%s" % connection.ops.prep_for_like_query(params[0])
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return rhs, params
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default_lookups['iendswith'] = IEndsWith
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class Between(BuiltinLookup):
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def get_rhs_op(self, connection, rhs):
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return "BETWEEN %s AND %s" % (rhs, rhs)
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class Year(Between):
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lookup_name = 'year'
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default_lookups['year'] = Year
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class Range(BuiltinLookup):
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lookup_name = 'range'
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def get_rhs_op(self, connection, rhs):
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return "BETWEEN %s AND %s" % (rhs[0], rhs[1])
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def process_rhs(self, compiler, connection):
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if self.rhs_is_direct_value():
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# rhs should be an iterable of 2 values, we use batch_process_rhs
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# to prepare/transform those values
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return self.batch_process_rhs(compiler, connection)
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else:
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return super(Range, self).process_rhs(compiler, connection)
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default_lookups['range'] = Range
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class DateLookup(BuiltinLookup):
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def process_lhs(self, compiler, connection, lhs=None):
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from django.db.models import DateTimeField
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lhs, params = super(DateLookup, self).process_lhs(compiler, connection, lhs)
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if isinstance(self.lhs.output_field, DateTimeField):
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tzname = timezone.get_current_timezone_name() if settings.USE_TZ else None
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sql, tz_params = connection.ops.datetime_extract_sql(self.extract_type, lhs, tzname)
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return connection.ops.lookup_cast(self.lookup_name) % sql, tz_params
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else:
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return connection.ops.date_extract_sql(self.lookup_name, lhs), []
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def get_rhs_op(self, connection, rhs):
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return '= %s' % rhs
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class Month(DateLookup):
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lookup_name = 'month'
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extract_type = 'month'
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default_lookups['month'] = Month
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class Day(DateLookup):
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lookup_name = 'day'
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extract_type = 'day'
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default_lookups['day'] = Day
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class WeekDay(DateLookup):
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lookup_name = 'week_day'
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extract_type = 'week_day'
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default_lookups['week_day'] = WeekDay
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class Hour(DateLookup):
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lookup_name = 'hour'
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extract_type = 'hour'
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default_lookups['hour'] = Hour
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class Minute(DateLookup):
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lookup_name = 'minute'
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extract_type = 'minute'
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default_lookups['minute'] = Minute
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class Second(DateLookup):
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lookup_name = 'second'
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extract_type = 'second'
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default_lookups['second'] = Second
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class IsNull(BuiltinLookup):
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lookup_name = 'isnull'
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def as_sql(self, compiler, connection):
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sql, params = compiler.compile(self.lhs)
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if self.rhs:
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return "%s IS NULL" % sql, params
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else:
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return "%s IS NOT NULL" % sql, params
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default_lookups['isnull'] = IsNull
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class Search(BuiltinLookup):
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lookup_name = 'search'
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def as_sql(self, compiler, connection):
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lhs, lhs_params = self.process_lhs(compiler, connection)
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rhs, rhs_params = self.process_rhs(compiler, connection)
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sql_template = connection.ops.fulltext_search_sql(field_name=lhs)
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return sql_template, lhs_params + rhs_params
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default_lookups['search'] = Search
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class Regex(BuiltinLookup):
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lookup_name = 'regex'
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def as_sql(self, compiler, connection):
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if self.lookup_name in connection.operators:
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return super(Regex, self).as_sql(compiler, connection)
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else:
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lhs, lhs_params = self.process_lhs(compiler, connection)
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rhs, rhs_params = self.process_rhs(compiler, connection)
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sql_template = connection.ops.regex_lookup(self.lookup_name)
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return sql_template % (lhs, rhs), lhs_params + rhs_params
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default_lookups['regex'] = Regex
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class IRegex(Regex):
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lookup_name = 'iregex'
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default_lookups['iregex'] = IRegex
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