97 lines
3.3 KiB
Python
97 lines
3.3 KiB
Python
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from copy import copy
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from django.db import connections
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from django.db.models import Field
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from django.db.models.expressions import RawSQL
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from django.db.models.sql.constants import INNER, LOUTER
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from django.db.models.sql.datastructures import Join
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from django.utils import six
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from judge.utils.cachedict import CacheDict
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def unique_together_left_join(queryset, model, link_field_name, filter_field_name, filter_value, parent_model=None):
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link_field = copy(model._meta.get_field(link_field_name).remote_field)
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filter_field = model._meta.get_field(filter_field_name)
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def restrictions(where_class, alias, related_alias):
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cond = where_class()
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cond.add(filter_field.get_lookup('exact')(filter_field.get_col(alias), filter_value), 'AND')
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return cond
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link_field.get_extra_restriction = restrictions
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if parent_model is not None:
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parent_alias = parent_model._meta.db_table
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else:
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parent_alias = queryset.query.get_initial_alias()
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return queryset.query.join(Join(model._meta.db_table, parent_alias, None, LOUTER, link_field, True))
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class RawSQLJoin(Join):
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def __init__(self, subquery, subquery_params, parent_alias, table_alias, join_type, join_field, nullable,
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filtered_relation=None):
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self.subquery_params = subquery_params
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super().__init__(subquery, parent_alias, table_alias, join_type, join_field, nullable, filtered_relation)
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def as_sql(self, compiler, connection):
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compiler.quote_cache[self.table_name] = '(%s)' % self.table_name
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sql, params = super().as_sql(compiler, connection)
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return sql, self.subquery_params + params
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class FakeJoinField:
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def __init__(self, joining_columns):
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self.joining_columns = joining_columns
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def get_joining_columns(self):
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return self.joining_columns
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def get_extra_restriction(self, where_class, alias, remote_alias):
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pass
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def join_sql_subquery(queryset, subquery, params, join_fields, alias, join_type=INNER, parent_model=None):
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if parent_model is not None:
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parent_alias = parent_model._meta.db_table
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else:
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parent_alias = queryset.query.get_initial_alias()
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queryset.query.external_aliases.add(alias)
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join = RawSQLJoin(subquery, params, parent_alias, alias, join_type, FakeJoinField(join_fields), join_type == LOUTER)
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queryset.query.join(join)
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join.table_alias = alias
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def RawSQLColumn(model, field=None):
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if isinstance(model, Field):
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field = model
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model = field.model
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if isinstance(field, six.string_types):
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field = model._meta.get_field(field)
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return RawSQL('%s.%s' % (model._meta.db_table, field.get_attname_column()[1]), ())
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def make_straight_join_query(QueryType):
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class Query(QueryType):
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def join(self, join, *args, **kwargs):
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alias = super().join(join, *args, **kwargs)
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join = self.alias_map[alias]
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if join.join_type == INNER:
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join.join_type = 'STRAIGHT_JOIN'
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return alias
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return Query
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straight_join_cache = CacheDict(make_straight_join_query)
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def use_straight_join(queryset):
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if connections[queryset.db].vendor != 'mysql':
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return
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try:
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cloner = queryset.query.chain
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except AttributeError:
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cloner = queryset.query.clone
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queryset.query = cloner(straight_join_cache[type(queryset.query)])
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