From 735492f03feb9e0edbeeab38c218e20b23d3a527 Mon Sep 17 00:00:00 2001
From: Benjamin Bollen <ben@erisindustries.com>
Date: Wed, 7 Sep 2016 12:27:15 +0200
Subject: [PATCH] erismint/vm: implement DelegateCall as scoped function
---
manager/eris-mint/evm/vm.go | 24 ++++++++++++++++++++++++
1 file changed, 24 insertions(+)
diff --git a/manager/eris-mint/evm/vm.go b/manager/eris-mint/evm/vm.go
index 7f0c7c05..45438f7f 100644
--- a/manager/eris-mint/evm/vm.go
+++ b/manager/eris-mint/evm/vm.go
@@ -147,6 +147,30 @@ func (vm *VM) Call(caller, callee *Account, code, input []byte, value int64, gas
return
}
+// DelegateCall is executed by the DELEGATECALL opcode, introduced as off Ethereum Homestead.
+// The intent of delegate call is to run the code of the callee in the storage context of the caller;
+// while preserving the original caller to the previous callee.
+// Different to the normal CALL or CALLCODE, the value does not need to be transferred to the callee.
+func (vm *VM) DelegateCall(caller, callee *Account, code, input []byte, value int64, gas *int64) (output []byte, err error) {
+
+ exception := new(string)
+ // fire the post call event (including exception if applicable)
+ defer vm.fireCallEvent(exception, &output, caller, callee, input, value, gas)
+
+ // DelegateCall does not transfer the value to the callee.
+
+ if len(code) > 0 {
+ vm.callDepth += 1
+ output, err = vm.call(caller, callee, code, input, value, gas)
+ vm.callDepth -= 1
+ if err != nil {
+ *exception = err.Error()
+ }
+ }
+
+ return
+}
+
// Try to deduct gasToUse from gasLeft. If ok return false, otherwise
// set err and return true.
func useGasNegative(gasLeft *int64, gasToUse int64, err *error) bool {
--
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