def do_approve(self, storage: StorageAPI, t_owner, t_spender, amount):
if not CheckWitness(t_owner):
print("Incorrect permission")
return False
if amount < 0:
print("Negative amount")
return False
from_balance = storage.get(t_owner)
# cannot approve an amount that is
# currently greater than the from balance
if from_balance >= amount:
approval_key = concat(t_owner, t_spender)
if amount == 0:
storage.delete(approval_key)
else:
storage.put(approval_key, amount)
OnApprove(t_owner, t_spender, amount)
return True
return False
def do_transfer_from(self, storage: StorageAPI, t_from, t_to, amount):
if amount <= 0:
return False
available_key = concat(t_from, t_to)
if len(available_key) != 40:
return False
if not CheckWitness(t_to):
print("to address is not the tx sender")
return False
available_to_to_addr = storage.get(available_key)
if available_to_to_addr < amount:
print("Insufficient funds approved")
return False
from_balance = storage.get(t_from)
if from_balance < amount:
print("Insufficient tokens in from balance")
return False
to_balance = storage.get(t_to)
new_from_balance = from_balance - amount
new_to_balance = to_balance + amount
storage.put(t_to, new_to_balance)
storage.put(t_from, new_from_balance)
print("transfer complete")
new_allowance = available_to_to_addr - amount
if new_allowance == 0:
print("removing all balance")
storage.delete(available_key)
else:
print("updating allowance to new allowance")
storage.put(available_key, new_allowance)
OnTransfer(t_from, t_to, amount)
return True
def do_transfer_from(self, storage: StorageAPI, t_from, t_to, amount):
if amount <= 0:
return False
available_key = concat(t_from, t_to)
if len(available_key) != 40:
return False
available_to_to_addr = storage.get(available_key)
if available_to_to_addr < amount:
print("Insufficient funds approved")
return False
from_balance = storage.get(t_from)
if from_balance < amount:
print("Insufficient tokens in from balance")
return False
# TODO: Check if target is crowdfunding
# If no crowdfunding, do normal transfer
to_balance = storage.get(t_to)
new_from_balance = from_balance - amount
new_to_balance = to_balance + amount
storage.put(t_to, new_to_balance)
storage.put(t_from, new_from_balance)
print("transfer complete")
new_allowance = available_to_to_addr - amount
if new_allowance == 0:
print("removing all balance")
storage.delete(available_key)
else:
print("updating allowance to new allowance")
storage.put(available_key, new_allowance)
OnTransfer(t_from, t_to, amount)
return True
def do_transfer(self, storage: StorageAPI, t_from, t_to, amount):
if amount <= 0:
return False
if len(t_to) != 20:
return False
if CheckWitness(t_from):
if t_from == t_to:
print("transfer to self!")
return True
from_val = storage.get(t_from)
if from_val < amount:
print("insufficient funds")
return False
if from_val == amount:
storage.delete(t_from)
else:
difference = from_val - amount
storage.put(t_from, difference)
to_value = storage.get(t_to)
to_total = to_value + amount
storage.put(t_to, to_total)
OnTransfer(t_from, t_to, amount)
return True
else:
print("from address is not the tx sender")
return False
def do_transfer(self, storage: StorageAPI, t_from, t_to, amount):
if amount <= 0:
return False
if len(t_to) != 20:
return False
if CheckWitness(t_from):
if t_from == t_to:
print("transfer to self!")
return True
from_val = storage.get(t_from)
if from_val < amount:
print("insufficient funds")
return False
# Update sender balance
if from_val == amount:
storage.delete(t_from)
else:
difference = from_val - amount
storage.put(t_from, difference)
# Check if target is crowdfunding. If not, do normal transfer.
is_crowdfunding = is_crowdfunding_address(t_to)
if is_crowdfunding:
Notify("is_crowdfunding!")
members = crowdfunding_get_members(t_to)
num_members = len(members)
amount_per_member = amount / num_members
msg = [
"Crowdfunding. Splitting amount across members:",
num_members, "amount per member:", amount_per_member
]
Notify(msg)
for member in members:
to_value = storage.get(member)
to_total = to_value + amount_per_member
storage.put(member, to_total)
OnTransfer(t_from, member, amount_per_member)
# Increase the crowdfunding total amount
crowdfunding_total_key = storage.get_crowdfunding_total_key(
t_to)
crowdfunding_total = storage.get(crowdfunding_total_key)
crowdfunding_total += amount
storage.put(crowdfunding_total_key, crowdfunding_total)
# Increase the crowdfunding number of contributions
crowdfunding_numcontrib_key = storage.get_crowdfunding_numcontrib_key(
t_to)
crowdfunding_numcontrib = storage.get(
crowdfunding_numcontrib_key)
crowdfunding_numcontrib += 1
storage.put(crowdfunding_numcontrib_key,
crowdfunding_numcontrib)
# All done in case of crowdfunding
return True
to_value = storage.get(t_to)
to_total = to_value + amount
storage.put(t_to, to_total)
OnTransfer(t_from, t_to, amount)
return True
else:
print("from address is not the tx sender")
return False
