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, 14 deletions

diff --git a/core/vm_env.go b/core/vm_env.go
index 599672382..e541eaef4 100644
--- a/core/vm_env.go
+++ b/core/vm_env.go
@@ -49,7 +49,6 @@ type VMEnv struct {
 
 	header    *types.Header            // Header information
 	chain     *BlockChain              // Blockchain handle
-	logs      []vm.StructLog           // Logs for the custom structured logger
 	getHashFn func(uint64) common.Hash // getHashFn callback is used to retrieve block hashes
 }
 
@@ -63,11 +62,6 @@ func NewEnv(state *state.StateDB, chainConfig *ChainConfig, chain *BlockChain, m
 		getHashFn:   GetHashFn(header.ParentHash, chain),
 	}
 
-	// if no log collector is present set self as the collector
-	if cfg.Logger.Collector == nil {
-		cfg.Logger.Collector = env
-	}
-
 	env.evm = vm.New(env, cfg)
 	return env
 }
@@ -121,11 +115,3 @@ func (self *VMEnv) DelegateCall(me vm.ContractRef, addr common.Address, data []b
 func (self *VMEnv) Create(me vm.ContractRef, data []byte, gas, price, value *big.Int) ([]byte, common.Address, error) {
 	return Create(self, me, data, gas, price, value)
 }
-
-func (self *VMEnv) StructLogs() []vm.StructLog {
-	return self.logs
-}
-
-func (self *VMEnv) AddStructLog(log vm.StructLog) {
-	self.logs = append(self.logs, log)
-}