Rename direction to step, apply checks consistently

This commit is contained in:
Mark Haines 2016-04-01 13:50:54 +01:00
parent e36bfbab38
commit a2866e2e6a
2 changed files with 16 additions and 16 deletions

View File

@ -97,7 +97,7 @@ class DataStore(RoomMemberStore, RoomStore,
db_conn, "events", "stream_ordering"
)
self._backfill_id_gen = StreamIdGenerator(
db_conn, "events", "stream_ordering", direction=-1
db_conn, "events", "stream_ordering", step=-1
)
self._receipts_id_gen = StreamIdGenerator(
db_conn, "receipts_linearized", "stream_id"

View File

@ -29,16 +29,16 @@ class IdGenerator(object):
return self._next_id
def _load_current_id(db_conn, table, column, direction=1):
def _load_current_id(db_conn, table, column, step=1):
cur = db_conn.cursor()
if direction == 1:
if step == 1:
cur.execute("SELECT MAX(%s) FROM %s" % (column, table,))
else:
cur.execute("SELECT MIN(%s) FROM %s" % (column, table,))
val, = cur.fetchone()
cur.close()
current_id = int(val) if val else direction
return (max if direction == 1 else min)(current_id, direction)
current_id = int(val) if val else step
return (max if step > 0 else min)(current_id, step)
class StreamIdGenerator(object):
@ -58,21 +58,21 @@ class StreamIdGenerator(object):
:param list extra_tables: List of pairs of database tables and columns to
use to source the initial value of the generator from. The value with
the largest magnitude is used.
:param int direction: which direction the stream ids grow in. +1 to grow
:param int step: which direction the stream ids grow in. +1 to grow
upwards, -1 to grow downwards.
Usage:
with stream_id_gen.get_next() as stream_id:
# ... persist event ...
"""
def __init__(self, db_conn, table, column, extra_tables=[], direction=1):
def __init__(self, db_conn, table, column, extra_tables=[], step=1):
self._lock = threading.Lock()
self._direction = direction
self._current = _load_current_id(db_conn, table, column, direction)
self._step = step
self._current = _load_current_id(db_conn, table, column, step)
for table, column in extra_tables:
self._current = (max if direction > 0 else min)(
self._current = (max if step > 0 else min)(
self._current,
_load_current_id(db_conn, table, column, direction)
_load_current_id(db_conn, table, column, step)
)
self._unfinished_ids = deque()
@ -83,7 +83,7 @@ class StreamIdGenerator(object):
# ... persist event ...
"""
with self._lock:
self._current += self._direction
self._current += self._step
next_id = self._current
self._unfinished_ids.append(next_id)
@ -106,9 +106,9 @@ class StreamIdGenerator(object):
"""
with self._lock:
next_ids = range(
self._current + self._direction,
self._current + self._direction * (n + 1),
self._direction
self._current + self._step,
self._current + self._step * (n + 1),
self._step
)
self._current += n
@ -132,7 +132,7 @@ class StreamIdGenerator(object):
"""
with self._lock:
if self._unfinished_ids:
return self._unfinished_ids[0] - self._direction
return self._unfinished_ids[0] - self._step
return self._current