def validate (db, source, destination, asset, quantity):
try:
util.get_asset_id(db, asset, util.CURRENT_BLOCK_INDEX)
except AssetError:
raise ValidateError('asset invalid')
try:
script.validate(source)
except AddressError:
raise ValidateError('source address invalid')
if destination:
raise ValidateError('destination exists')
if asset == config.SCH:
raise ValidateError('cannot destroy {}'.format(config.SCH))
if type(quantity) != int:
raise ValidateError('quantity not integer')
if quantity > config.MAX_INT:
raise ValidateError('quantity too large')
if quantity < 0:
raise ValidateError('quantity negative')
if util.get_balance(db, source, asset) < quantity:
raise BalanceError('balance insufficient')
if not config.TESTNET:
raise ValidateError('disabled on mainnet')
def validate(db, source, destination, asset, quantity, block_index):
try:
util.get_asset_id(db, asset, block_index)
except AssetError:
raise ValidateError('asset invalid')
try:
script.validate(source)
except AddressError:
raise ValidateError('source address invalid')
try:
script.validate(destination)
except AddressError:
raise ValidateError('destination address invalid')
if asset == config.SCH:
raise ValidateError('cannot send {}'.format(config.SCH))
if type(quantity) != int:
raise ValidateError('quantity not integer')
if quantity > config.MAX_INT:
raise ValidateError('quantity too large')
if quantity <= 0:
raise ValidateError('quantity non‐positive')
if util.get_balance(db, source, asset) < quantity:
raise BalanceError('balance insufficient')
def compose(db, source, give_asset, give_quantity, get_asset, get_quantity, expiration, fee_required):
cursor = db.cursor()
# Check balance.
if give_asset != config.SCH:
balances = list(
cursor.execute("""SELECT * FROM balances WHERE (address = ? AND asset = ?)""", (source, give_asset))
)
if not balances or balances[0]["quantity"] < give_quantity:
raise exceptions.ComposeError("insufficient funds")
problems = validate(
db,
source,
give_asset,
give_quantity,
get_asset,
get_quantity,
expiration,
fee_required,
util.CURRENT_BLOCK_INDEX,
)
if problems:
raise exceptions.ComposeError(problems)
give_id = util.get_asset_id(db, give_asset, util.CURRENT_BLOCK_INDEX)
get_id = util.get_asset_id(db, get_asset, util.CURRENT_BLOCK_INDEX)
data = struct.pack(config.TXTYPE_FORMAT, ID)
data += struct.pack(FORMAT, give_id, give_quantity, get_id, get_quantity, expiration, fee_required)
cursor.close()
return (source, [], data)
def pack(db, asset, quantity, tag):
data = struct.pack(config.TXTYPE_FORMAT, ID)
data += struct.pack(FORMAT, util.get_asset_id(db, asset, util.CURRENT_BLOCK_INDEX), quantity, tag)
return data