internal static bool VerifyWitnesses(this IVerifiable verifiable, StoreView snapshot, long gas)
{
if (gas < 0)
{
return(false);
}
if (gas > MaxVerificationGas)
{
gas = MaxVerificationGas;
}
UInt160[] hashes;
try
{
hashes = verifiable.GetScriptHashesForVerifying(snapshot);
}
catch (InvalidOperationException)
{
return(false);
}
if (hashes.Length != verifiable.Witnesses.Length)
{
return(false);
}
for (int i = 0; i < hashes.Length; i++)
{
int offset;
ContractMethodDescriptor init = null;
byte[] verification = verifiable.Witnesses[i].VerificationScript;
if (verification.Length == 0)
{
ContractState cs = snapshot.Contracts.TryGet(hashes[i]);
if (cs is null)
{
return(false);
}
ContractMethodDescriptor md = cs.Manifest.Abi.GetMethod("verify");
if (md is null)
{
return(false);
}
verification = cs.Script;
offset = md.Offset;
init = cs.Manifest.Abi.GetMethod("_initialize");
}
else
{
if (hashes[i] != verifiable.Witnesses[i].ScriptHash)
{
return(false);
}
offset = 0;
}
using (ApplicationEngine engine = ApplicationEngine.Create(TriggerType.Verification, verifiable, snapshot.Clone(), gas))
{
engine.LoadScript(verification, CallFlags.None).InstructionPointer = offset;
if (init != null)
{
engine.LoadClonedContext(init.Offset);
}
engine.LoadScript(verifiable.Witnesses[i].InvocationScript, CallFlags.None);
if (engine.Execute() == VMState.FAULT)
{
return(false);
}
if (engine.ResultStack.Count != 1 || !engine.ResultStack.Pop().GetBoolean())
{
return(false);
}
gas -= engine.GasConsumed;
}
}
return(true);
}