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Code Issues 32 Releases Wiki Activity

Fixed #17644 -- Changed Query.alias_map to use namedtuples

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This makes the code easier to understand and may even have a benefit in memory usage (namedtuples instead of dicts). Thanks, lrekucki and akaariai
This commit is contained in:
Adrian Holovaty
2012-04-29 17:50:48 -05:00
parent af71ce06ea
commit 6ff118cdb9
4 changed files with 56 additions and 57 deletions
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71
django/db/models/sql/query.py
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@@ -101,7 +101,11 @@ class Query(object):
def __init__(self, model, where=WhereNode):
self.model = model
self.alias_refcount = SortedDict()
self.alias_map = {} # Maps alias to join information
# alias_map is the most important data structure regarding joins.
# It's used for recording which joins exist in the query and what
# type they are. The key is the alias of the joined table (possibly
# the table name) and the value is JoinInfo from constants.py.
self.alias_map = {}
self.table_map = {} # Maps table names to list of aliases.
self.join_map = {}
self.default_cols = True
@@ -686,11 +690,11 @@ class Query(object):
Returns True if the join was promoted by this call.
"""
if ((unconditional or self.alias_map[alias][NULLABLE]) and
self.alias_map[alias][JOIN_TYPE] != self.LOUTER):
data = list(self.alias_map[alias])
data[JOIN_TYPE] = self.LOUTER
self.alias_map[alias] = tuple(data)
if ((unconditional or self.alias_map[alias].nullable) and
self.alias_map[alias].join_type != self.LOUTER):
data = self.alias_map[alias]
data = data._replace(join_type=self.LOUTER)
self.alias_map[alias] = data
return True
return False
@@ -730,7 +734,7 @@ class Query(object):
continue
if (alias not in initial_refcounts or
self.alias_refcount[alias] == initial_refcounts[alias]):
parent = self.alias_map[alias][LHS_ALIAS]
parent = self.alias_map[alias].lhs_alias
must_promote = considered.get(parent, False)
promoted = self.promote_alias(alias, must_promote)
considered[alias] = must_promote or promoted
@@ -767,14 +771,14 @@ class Query(object):
aliases = tuple([change_map.get(a, a) for a in aliases])
self.join_map[k] = aliases
for old_alias, new_alias in change_map.iteritems():
alias_data = list(self.alias_map[old_alias])
alias_data[RHS_ALIAS] = new_alias
alias_data = self.alias_map[old_alias]
alias_data = alias_data._replace(rhs_alias=new_alias)
self.alias_refcount[new_alias] = self.alias_refcount[old_alias]
del self.alias_refcount[old_alias]
self.alias_map[new_alias] = tuple(alias_data)
self.alias_map[new_alias] = alias_data
del self.alias_map[old_alias]
table_aliases = self.table_map[alias_data[TABLE_NAME]]
table_aliases = self.table_map[alias_data.table_name]
for pos, alias in enumerate(table_aliases):
if alias == old_alias:
table_aliases[pos] = new_alias
@@ -789,11 +793,10 @@ class Query(object):
# 3. Update any joins that refer to the old alias.
for alias, data in self.alias_map.iteritems():
lhs = data[LHS_ALIAS]
lhs = data.lhs_alias
if lhs in change_map:
data = list(data)
data[LHS_ALIAS] = change_map[lhs]
self.alias_map[alias] = tuple(data)
data = data._replace(lhs_alias=change_map[lhs])
self.alias_map[alias] = data
def bump_prefix(self, exceptions=()):
"""
@@ -876,7 +879,7 @@ class Query(object):
"""
lhs, table, lhs_col, col = connection
if lhs in self.alias_map:
lhs_table = self.alias_map[lhs][TABLE_NAME]
lhs_table = self.alias_map[lhs].table_name
else:
lhs_table = lhs
@@ -889,11 +892,11 @@ class Query(object):
if not always_create:
for alias in self.join_map.get(t_ident, ()):
if alias not in exclusions:
if lhs_table and not self.alias_refcount[self.alias_map[alias][LHS_ALIAS]]:
if lhs_table and not self.alias_refcount[self.alias_map[alias].lhs_alias]:
# The LHS of this join tuple is no longer part of the
# query, so skip this possibility.
continue
if self.alias_map[alias][LHS_ALIAS] != lhs:
if self.alias_map[alias].lhs_alias != lhs:
continue
self.ref_alias(alias)
if promote:
@@ -910,7 +913,7 @@ class Query(object):
join_type = self.LOUTER
else:
join_type = self.INNER
join = (table, alias, join_type, lhs, lhs_col, col, nullable)
join = JoinInfo(table, alias, join_type, lhs, lhs_col, col, nullable)
self.alias_map[alias] = join
if t_ident in self.join_map:
self.join_map[t_ident] += (alias,)
@@ -1150,7 +1153,7 @@ class Query(object):
# also be promoted, regardless of whether they have been
# promoted as a result of this pass through the tables.
unconditional = (unconditional or
self.alias_map[join][JOIN_TYPE] == self.LOUTER)
self.alias_map[join].join_type == self.LOUTER)
if join == table and self.alias_refcount[join] > 1:
# We have more than one reference to this join table.
# This means that we are dealing with two different query
@@ -1181,8 +1184,8 @@ class Query(object):
if lookup_type != 'isnull':
if len(join_list) > 1:
for alias in join_list:
if self.alias_map[alias][JOIN_TYPE] == self.LOUTER:
j_col = self.alias_map[alias][RHS_JOIN_COL]
if self.alias_map[alias].join_type == self.LOUTER:
j_col = self.alias_map[alias].rhs_join_col
entry = self.where_class()
entry.add(
(Constraint(alias, j_col, None), 'isnull', True),
@@ -1510,7 +1513,7 @@ class Query(object):
join_list = join_list[:penultimate]
final = penultimate
penultimate = last.pop()
col = self.alias_map[extra[0]][LHS_JOIN_COL]
col = self.alias_map[extra[0]].lhs_join_col
for alias in extra:
self.unref_alias(alias)
else:
@@ -1518,12 +1521,12 @@ class Query(object):
alias = join_list[-1]
while final > 1:
join = self.alias_map[alias]
if (col != join[RHS_JOIN_COL] or join[JOIN_TYPE] != self.INNER or
if (col != join.rhs_join_col or join.join_type != self.INNER or
nonnull_check):
break
self.unref_alias(alias)
alias = join[LHS_ALIAS]
col = join[LHS_JOIN_COL]
alias = join.lhs_alias
col = join.lhs_join_col
join_list.pop()
final -= 1
if final == penultimate:
@@ -1646,10 +1649,10 @@ class Query(object):
col = target.column
if len(joins) > 1:
join = self.alias_map[final_alias]
if col == join[RHS_JOIN_COL]:
if col == join.rhs_join_col:
self.unref_alias(final_alias)
final_alias = join[LHS_ALIAS]
col = join[LHS_JOIN_COL]
final_alias = join.lhs_alias
col = join.lhs_join_col
joins = joins[:-1]
self.promote_alias_chain(joins[1:])
self.select.append((final_alias, col))
@@ -1923,7 +1926,7 @@ class Query(object):
alias = self.get_initial_alias()
field, col, opts, joins, last, extra = self.setup_joins(
start.split(LOOKUP_SEP), opts, alias, False)
select_col = self.alias_map[joins[1]][LHS_JOIN_COL]
select_col = self.alias_map[joins[1]].lhs_join_col
select_alias = alias
# The call to setup_joins added an extra reference to everything in
@@ -1936,12 +1939,12 @@ class Query(object):
# is *always* the same value as lhs).
for alias in joins[1:]:
join_info = self.alias_map[alias]
if (join_info[LHS_JOIN_COL] != select_col
or join_info[JOIN_TYPE] != self.INNER):
if (join_info.lhs_join_col != select_col
or join_info.join_type != self.INNER):
break
self.unref_alias(select_alias)
select_alias = join_info[RHS_ALIAS]
select_col = join_info[RHS_JOIN_COL]
select_alias = join_info.rhs_alias
select_col = join_info.rhs_join_col
self.select = [(select_alias, select_col)]
self.remove_inherited_models()