internal/ethapi: Add support for fetching information about the current call in JS traces

internal/ethapi/tracer.go

@@ -23,6 +23,7 @@ import (
 	"math/big"
 
 	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/common/hexutil"
 	"github.com/ethereum/go-ethereum/core/vm"
 	"github.com/robertkrimen/otto"
 )
@@ -164,6 +165,37 @@ func (dw *dbWrapper) toValue(vm *otto.Otto) otto.Value {
 	return value
 }
 
+// contractWrapper provides a JS wrapper around vm.Contract
+type contractWrapper struct {
+	contract *vm.Contract
+}
+
+func (c *contractWrapper) caller() common.Address {
+	return c.contract.Caller()
+}
+
+func (c *contractWrapper) address() common.Address {
+	return c.contract.Address()
+}
+
+func (c *contractWrapper) value() *big.Int {
+	return c.contract.Value()
+}
+
+func (c *contractWrapper) calldata() []byte {
+	return c.contract.Input
+}
+
+func (c *contractWrapper) toValue(vm *otto.Otto) otto.Value {
+	value, _ := vm.ToValue(c)
+	obj := value.Object()
+	obj.Set("caller", c.caller)
+	obj.Set("address", c.address)
+	obj.Set("value", c.value)
+	obj.Set("calldata", c.calldata)
+	return value
+}
+
 // JavascriptTracer provides an implementation of Tracer that evaluates a
 // Javascript function for each VM execution step.
 type JavascriptTracer struct {
@@ -177,6 +209,8 @@ type JavascriptTracer struct {
 	stackvalue    otto.Value             // JS view of `stack`
 	db            *dbWrapper             // Wrapper around the VM environment
 	dbvalue       otto.Value             // JS view of `db`
+	contract      *contractWrapper       // Wrapper around the contract object
+	contractvalue otto.Value             // JS view of `contract`
 	err           error                  // Error, if one has occurred
 }
 
@@ -189,6 +223,7 @@ func NewJavascriptTracer(code string) (*JavascriptTracer, error) {
 
 	// Set up builtins for this environment
 	vm.Set("big", &fakeBig{})
+	vm.Set("toHex", hexutil.Encode)
 
 	jstracer, err := vm.Object("(" + code + ")")
 	if err != nil {
@@ -220,6 +255,7 @@ func NewJavascriptTracer(code string) (*JavascriptTracer, error) {
 	mem := &memoryWrapper{}
 	stack := &stackWrapper{}
 	db := &dbWrapper{}
+	contract := &contractWrapper{}
 
 	return &JavascriptTracer{
 		vm:            vm,
@@ -232,6 +268,8 @@ func NewJavascriptTracer(code string) (*JavascriptTracer, error) {
 		stackvalue:    stack.toValue(vm),
 		db:            db,
 		dbvalue:       db.toValue(vm),
+		contract:      contract,
+		contractvalue: contract.toValue(vm),
 		err:           nil,
 	}, nil
 }
@@ -283,6 +321,7 @@ func (jst *JavascriptTracer) CaptureState(env *vm.EVM, pc uint64, op vm.OpCode,
 		jst.memory.memory = memory
 		jst.stack.stack = stack
 		jst.db.db = env.StateDB
+		jst.contract.contract = contract
 
 		ocw := &opCodeWrapper{op}
 
@@ -292,6 +331,7 @@ func (jst *JavascriptTracer) CaptureState(env *vm.EVM, pc uint64, op vm.OpCode,
 		jst.log["gasPrice"] = cost
 		jst.log["memory"] = jst.memvalue
 		jst.log["stack"] = jst.stackvalue
+		jst.log["contract"] = jst.contractvalue
 		jst.log["depth"] = depth
 		jst.log["account"] = contract.Address()
 		jst.log["err"] = err