core/vm: Refactor tracing to make Tracer the main interface

This CL makes several refactors:
 - Define a Tracer interface, implementing the `CaptureState` method
 - Add the VM environment as the first argument of
   `Tracer.CaptureState`
 - Rename existing functionality `StructLogger` an make it an
   implementation of `Tracer`
 - Delete `StructLogCollector` and make `StructLogger` collect the logs
   directly
 - Change all callers to use the new `StructLogger` where necessary and
   extract logs from that.
 - Deletes the apparently obsolete and likely nonfunctional 'TraceCall'
   from the eth API.

Callers that only wish accumulated logs can use the `StructLogger`
implementation straightforwardly. Callers that wish to efficiently
capture VM traces and operate on them without excessive copying can now
implement the `Tracer` interface to receive VM state at each step and
do with it as they wish.

This CL also removes the accumulation of logs from the vm.Environment;
this was necessary as part of the refactor, but also simplifies it by
removing a responsibility that doesn't directly belong to the
Environment.

1 files changed, 0 insertions, 10 deletions

diff --git a/tests/util.go b/tests/util.go
index 8d1917d15..79c3bfad1 100644
--- a/tests/util.go
+++ b/tests/util.go
@@ -166,8 +166,6 @@ type Env struct {
 	difficulty *big.Int
 	gasLimit   *big.Int
 
-	logs []vm.StructLog
-
 	vmTest bool
 
 	evm *vm.EVM
@@ -181,14 +179,6 @@ func NewEnv(ruleSet RuleSet, state *state.StateDB) *Env {
 	return env
 }
 
-func (self *Env) StructLogs() []vm.StructLog {
-	return self.logs
-}
-
-func (self *Env) AddStructLog(log vm.StructLog) {
-	self.logs = append(self.logs, log)
-}
-
 func NewEnvFromMap(ruleSet RuleSet, state *state.StateDB, envValues map[string]string, exeValues map[string]string) *Env {
 	env := NewEnv(ruleSet, state)