From 17d92233d9e64b642fed9a992556f7ff7d6fda18 Mon Sep 17 00:00:00 2001
From: Nick Johnson <arachnid@notdot.net>
Date: Tue, 17 Jan 2017 11:19:50 +0000
Subject: cmd/geth, core: add support for recording SHA3 preimages (#3543)

---
 core/state/journal.go |  7 +++++++
 core/state/statedb.go | 26 +++++++++++++++++++++++++-
 2 files changed, 32 insertions(+), 1 deletion(-)

(limited to 'core/state')

diff --git a/core/state/journal.go b/core/state/journal.go
index d1e73e7d0..68d07fa03 100644
--- a/core/state/journal.go
+++ b/core/state/journal.go
@@ -67,6 +67,9 @@ type (
 	addLogChange struct {
 		txhash common.Hash
 	}
+	addPreimageChange struct {
+		hash common.Hash
+	}
 	touchChange struct {
 		account *common.Address
 		prev    bool
@@ -127,3 +130,7 @@ func (ch addLogChange) undo(s *StateDB) {
 		s.logs[ch.txhash] = logs[:len(logs)-1]
 	}
 }
+
+func (ch addPreimageChange) undo(s *StateDB) {
+	delete(s.preimages, ch.hash)
+}
diff --git a/core/state/statedb.go b/core/state/statedb.go
index 063e2b469..bbccba9fb 100644
--- a/core/state/statedb.go
+++ b/core/state/statedb.go
@@ -75,6 +75,8 @@ type StateDB struct {
 	logs         map[common.Hash][]*types.Log
 	logSize      uint
 
+	preimages map[common.Hash][]byte
+
 	// Journal of state modifications. This is the backbone of
 	// Snapshot and RevertToSnapshot.
 	journal        journal
@@ -99,6 +101,7 @@ func New(root common.Hash, db ethdb.Database) (*StateDB, error) {
 		stateObjectsDirty: make(map[common.Address]struct{}),
 		refund:            new(big.Int),
 		logs:              make(map[common.Hash][]*types.Log),
+		preimages:         make(map[common.Hash][]byte),
 	}, nil
 }
 
@@ -120,6 +123,7 @@ func (self *StateDB) New(root common.Hash) (*StateDB, error) {
 		stateObjectsDirty: make(map[common.Address]struct{}),
 		refund:            new(big.Int),
 		logs:              make(map[common.Hash][]*types.Log),
+		preimages:         make(map[common.Hash][]byte),
 	}, nil
 }
 
@@ -141,6 +145,7 @@ func (self *StateDB) Reset(root common.Hash) error {
 	self.txIndex = 0
 	self.logs = make(map[common.Hash][]*types.Log)
 	self.logSize = 0
+	self.preimages = make(map[common.Hash][]byte)
 	self.clearJournalAndRefund()
 
 	return nil
@@ -199,6 +204,21 @@ func (self *StateDB) Logs() []*types.Log {
 	return logs
 }
 
+// AddPreimage records a SHA3 preimage seen by the VM.
+func (self *StateDB) AddPreimage(hash common.Hash, preimage []byte) {
+	if _, ok := self.preimages[hash]; !ok {
+		self.journal = append(self.journal, addPreimageChange{hash: hash})
+		pi := make([]byte, len(preimage))
+		copy(pi, preimage)
+		self.preimages[hash] = pi
+	}
+}
+
+// Preimages returns a list of SHA3 preimages that have been submitted.
+func (self *StateDB) Preimages() map[common.Hash][]byte {
+	return self.preimages
+}
+
 func (self *StateDB) AddRefund(gas *big.Int) {
 	self.journal = append(self.journal, refundChange{prev: new(big.Int).Set(self.refund)})
 	self.refund.Add(self.refund, gas)
@@ -477,8 +497,9 @@ func (self *StateDB) Copy() *StateDB {
 		refund:            new(big.Int).Set(self.refund),
 		logs:              make(map[common.Hash][]*types.Log, len(self.logs)),
 		logSize:           self.logSize,
+		preimages:         make(map[common.Hash][]byte),
 	}
-	// Copy the dirty states and logs
+	// Copy the dirty states, logs, and preimages
 	for addr := range self.stateObjectsDirty {
 		state.stateObjects[addr] = self.stateObjects[addr].deepCopy(state, state.MarkStateObjectDirty)
 		state.stateObjectsDirty[addr] = struct{}{}
@@ -487,6 +508,9 @@ func (self *StateDB) Copy() *StateDB {
 		state.logs[hash] = make([]*types.Log, len(logs))
 		copy(state.logs[hash], logs)
 	}
+	for hash, preimage := range self.preimages {
+		state.preimages[hash] = preimage
+	}
 	return state
 }
 
-- 
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