# Django 3.2.12 documentation

# Source code for django.contrib.postgres.indexes

    from django.db import NotSupportedError
    from django.db.models import Func, Index
    from django.utils.functional import cached_property

    __all__ = [
        'BloomIndex', 'BrinIndex', 'BTreeIndex', 'GinIndex', 'GistIndex',
        'HashIndex', 'SpGistIndex',
    ]

    class PostgresIndex(Index):

        @cached_property
        def max_name_length(self):
            # Allow an index name longer than 30 characters when the suffix is
            # longer than the usual 3 character limit. The 30 character limit for
            # cross-database compatibility isn't applicable to PostgreSQL-specific
            # indexes.
            return Index.max_name_length - len(Index.suffix) + len(self.suffix)

        def create_sql(self, model, schema_editor, using='', **kwargs):
            self.check_supported(schema_editor)
            statement = super().create_sql(model, schema_editor, using=' USING %s' % self.suffix, **kwargs)
            with_params = self.get_with_params()
            if with_params:
                statement.parts['extra'] = 'WITH (%s) %s' % (
                    ', '.join(with_params),
                    statement.parts['extra'],
                )
            return statement

        def check_supported(self, schema_editor):
            pass

        def get_with_params(self):
            return []

    class BloomIndex(PostgresIndex):
        suffix = 'bloom'

        def __init__(self, *expressions, length=None, columns=(), **kwargs):
            super().__init__(*expressions, **kwargs)
            if len(self.fields) > 32:
                raise ValueError('Bloom indexes support a maximum of 32 fields.')
            if not isinstance(columns, (list, tuple)):
                raise ValueError('BloomIndex.columns must be a list or tuple.')
            if len(columns) > len(self.fields):
                raise ValueError(
                    'BloomIndex.columns cannot have more values than fields.'
                )
            if not all(0 < col <= 4095 for col in columns):
                raise ValueError(
                    'BloomIndex.columns must contain integers from 1 to 4095.',
                )
            if length is not None and not 0 < length <= 4096:
                raise ValueError(
                    'BloomIndex.length must be None or an integer from 1 to 4096.',
                )
            self.length = length
            self.columns = columns

        def deconstruct(self):
            path, args, kwargs = super().deconstruct()
            if self.length is not None:
                kwargs['length'] = self.length
            if self.columns:
                kwargs['columns'] = self.columns
            return path, args, kwargs

        def get_with_params(self):
            with_params = []
            if self.length is not None:
                with_params.append('length = %d' % self.length)
            if self.columns:
                with_params.extend(
                    'col%d = %d' % (i, v)
                    for i, v in enumerate(self.columns, start=1)
                )
            return with_params

    class BrinIndex(PostgresIndex):
        suffix = 'brin'

        def __init__(self, *expressions, autosummarize=None, pages_per_range=None, **kwargs):
            if pages_per_range is not None and pages_per_range <= 0:
                raise ValueError('pages_per_range must be None or a positive integer')
            self.autosummarize = autosummarize
            self.pages_per_range = pages_per_range
            super().__init__(*expressions, **kwargs)

        def deconstruct(self):
            path, args, kwargs = super().deconstruct()
            if self.autosummarize is not None:
                kwargs['autosummarize'] = self.autosummarize
            if self.pages_per_range is not None:
                kwargs['pages_per_range'] = self.pages_per_range
            return path, args, kwargs

        def check_supported(self, schema_editor):
            if self.autosummarize and not schema_editor.connection.features.has_brin_autosummarize:
                raise NotSupportedError('BRIN option autosummarize requires PostgreSQL 10+.')

        def get_with_params(self):
            with_params = []
            if self.autosummarize is not None:
                with_params.append('autosummarize = %s' % ('on' if self.autosummarize else 'off'))
            if self.pages_per_range is not None:
                with_params.append('pages_per_range = %d' % self.pages_per_range)
            return with_params

    class BTreeIndex(PostgresIndex):
        suffix = 'btree'

        def __init__(self, *expressions, fillfactor=None, **kwargs):
            self.fillfactor = fillfactor
            super().__init__(*expressions, **kwargs)

        def deconstruct(self):
            path, args, kwargs = super().deconstruct()
            if self.fillfactor is not None:
                kwargs['fillfactor'] = self.fillfactor
            return path, args, kwargs

        def get_with_params(self):
            with_params = []
            if self.fillfactor is not None:
                with_params.append('fillfactor = %d' % self.fillfactor)
            return with_params

    class GinIndex(PostgresIndex):
        suffix = 'gin'

        def __init__(self, *expressions, fastupdate=None, gin_pending_list_limit=None, **kwargs):
            self.fastupdate = fastupdate
            self.gin_pending_list_limit = gin_pending_list_limit
            super().__init__(*expressions, **kwargs)

        def deconstruct(self):
            path, args, kwargs = super().deconstruct()
            if self.fastupdate is not None:
                kwargs['fastupdate'] = self.fastupdate
            if self.gin_pending_list_limit is not None:
                kwargs['gin_pending_list_limit'] = self.gin_pending_list_limit
            return path, args, kwargs

        def get_with_params(self):
            with_params = []
            if self.gin_pending_list_limit is not None:
                with_params.append('gin_pending_list_limit = %d' % self.gin_pending_list_limit)
            if self.fastupdate is not None:
                with_params.append('fastupdate = %s' % ('on' if self.fastupdate else 'off'))
            return with_params

    class GistIndex(PostgresIndex):
        suffix = 'gist'

        def __init__(self, *expressions, buffering=None, fillfactor=None, **kwargs):
            self.buffering = buffering
            self.fillfactor = fillfactor
            super().__init__(*expressions, **kwargs)

        def deconstruct(self):
            path, args, kwargs = super().deconstruct()
            if self.buffering is not None:
                kwargs['buffering'] = self.buffering
            if self.fillfactor is not None:
                kwargs['fillfactor'] = self.fillfactor
            return path, args, kwargs

        def get_with_params(self):
            with_params = []
            if self.buffering is not None:
                with_params.append('buffering = %s' % ('on' if self.buffering else 'off'))
            if self.fillfactor is not None:
                with_params.append('fillfactor = %d' % self.fillfactor)
            return with_params

        def check_supported(self, schema_editor):
            if self.include and not schema_editor.connection.features.supports_covering_gist_indexes:
                raise NotSupportedError('Covering GiST indexes requires PostgreSQL 12+.')

    class HashIndex(PostgresIndex):
        suffix = 'hash'

        def __init__(self, *expressions, fillfactor=None, **kwargs):
            self.fillfactor = fillfactor
            super().__init__(*expressions, **kwargs)

        def deconstruct(self):
            path, args, kwargs = super().deconstruct()
            if self.fillfactor is not None:
                kwargs['fillfactor'] = self.fillfactor
            return path, args, kwargs

        def get_with_params(self):
            with_params = []
            if self.fillfactor is not None:
                with_params.append('fillfactor = %d' % self.fillfactor)
            return with_params

    class SpGistIndex(PostgresIndex):
        suffix = 'spgist'

        def __init__(self, *expressions, fillfactor=None, **kwargs):
            self.fillfactor = fillfactor
            super().__init__(*expressions, **kwargs)

        def deconstruct(self):
            path, args, kwargs = super().deconstruct()
            if self.fillfactor is not None:
                kwargs['fillfactor'] = self.fillfactor
            return path, args, kwargs

        def get_with_params(self):
            with_params = []
            if self.fillfactor is not None:
                with_params.append('fillfactor = %d' % self.fillfactor)
            return with_params

    class OpClass(Func):
        template = '%(expressions)s %(name)s'

        def __init__(self, expression, name):
            super().__init__(expression, name=name)