def lock_bundles(cursor, transfer, bundles=None, prefer_bundles_from=-1):
assert transfer.status == 'pre'
tipper, tippee = transfer.tipper, transfer.tippee
currency = transfer.amount.currency
if bundles:
# Refetch the bundles to ensure validity and prevent race conditions
bundles = tuple(bundles)
bundles = cursor.all(
"""
SELECT b.*
FROM cash_bundles b
WHERE b.owner = %(tipper)s
AND b.withdrawal IS NULL
AND b.locked_for IS NULL
AND b.amount::currency = %(currency)s
AND b.id IN %(bundles)s
ORDER BY b.ts
""", locals())
else:
bundles = cursor.all(
"""
SELECT b.*
FROM cash_bundles b
JOIN exchanges e ON e.id = b.origin
WHERE b.owner = %(tipper)s
AND b.withdrawal IS NULL
AND b.locked_for IS NULL
AND b.amount::currency = %(currency)s
ORDER BY b.origin = %(prefer_bundles_from)s DESC
, e.participant = %(tippee)s DESC
, b.ts
""", locals())
transferable = sum(b.amount for b in bundles)
x = transfer.amount
if x > transferable:
raise NegativeBalance()
for b in bundles:
if x >= b.amount:
cursor.run(
"""
UPDATE cash_bundles
SET locked_for = %s
WHERE id = %s
""", (transfer.id, b.id))
x -= b.amount
if x == 0:
break
else:
cursor.run(
"""
UPDATE cash_bundles
SET amount = (amount - %s)
WHERE id = %s;
INSERT INTO cash_bundles
(owner, origin, amount, ts, locked_for, wallet_id)
VALUES (%s, %s, %s, %s, %s, %s);
""", (x, b.id, transfer.tipper, b.origin, x, b.ts, transfer.id,
b.wallet_id))
break
def check_balances(cursor):
"""Check that balances aren't becoming (more) negative
"""
oops = cursor.one("""
SELECT p.id
, p.username
, p2.balances
FROM payday_participants p2
JOIN participants p ON p.id = p2.id
WHERE (p2.balances).EUR < 0 OR (p2.balances).USD < 0
LIMIT 1
""")
if oops:
log(oops)
raise NegativeBalance()
log("Checked the balances.")
def lock_bundles(cursor, transfer, bundles=None, prefer_bundles_from=-1):
assert transfer.status == 'pre'
cursor.run("LOCK TABLE cash_bundles IN EXCLUSIVE MODE")
tipper, tippee = transfer.tipper, transfer.tippee
currency = transfer.amount.currency
bundles = bundles or cursor.all(
"""
SELECT b.*
FROM cash_bundles b
JOIN exchanges e ON e.id = b.origin
WHERE b.owner = %(tipper)s
AND b.withdrawal IS NULL
AND b.locked_for IS NULL
AND b.amount::currency = %(currency)s
ORDER BY b.origin = %(prefer_bundles_from)s DESC
, e.participant = %(tippee)s DESC
, b.ts
""", locals())
transferable = sum(b.amount for b in bundles)
x = transfer.amount
if x > transferable:
raise NegativeBalance()
for b in bundles:
if x >= b.amount:
cursor.run(
"""
UPDATE cash_bundles
SET locked_for = %s
WHERE id = %s
""", (transfer.id, b.id))
x -= b.amount
if x == 0:
break
else:
cursor.run(
"""
UPDATE cash_bundles
SET amount = (amount - %s)
WHERE id = %s;
INSERT INTO cash_bundles
(owner, origin, amount, ts, locked_for, wallet_id)
VALUES (%s, %s, %s, %s, %s, %s);
""", (x, b.id, transfer.tipper, b.origin, x, b.ts, transfer.id,
b.wallet_id))
break
def check_balances(cursor):
"""Check that balances aren't becoming (more) negative
"""
oops = cursor.one("""
SELECT *
FROM (
SELECT p.id
, p.username
, (p.balance + p2.new_balance - p2.old_balance) AS new_balance
, p.balance AS cur_balance
FROM payday_participants p2
JOIN participants p ON p.id = p2.id
AND p2.new_balance <> p2.old_balance
) foo
WHERE new_balance < 0 AND new_balance < cur_balance
LIMIT 1
""")
if oops:
log(oops)
raise NegativeBalance()
log("Checked the balances.")