cmd/geth/config.go

@@ -178,6 +178,10 @@ func makeFullNode(ctx *cli.Context) *node.Node {
 	if cfg.Ethstats.URL != "" {
 		utils.RegisterEthStatsService(stack, cfg.Ethstats.URL)
 	}
+
+	if ctx.GlobalBool(utils.StateDiffFlag.Name) {
+		utils.RegisterStateDiffService(stack)
+	}
 	return stack
 }
 

cmd/geth/main.go

@@ -132,6 +132,7 @@ var (
 		utils.GpoPercentileFlag,
 		utils.EWASMInterpreterFlag,
 		utils.EVMInterpreterFlag,
+		utils.StateDiffFlag,
 		configFileFlag,
 	}
 

cmd/geth/usage.go

@@ -245,6 +245,12 @@ var AppHelpFlagGroups = []flagGroup{
 			utils.MinerLegacyExtraDataFlag,
 		},
 	},
+	{
+		Name: "STATE DIFF",
+		Flags: []cli.Flag{
+			utils.StateDiffFlag,
+		},
+	},
 	{
 		Name: "MISC",
 	},

cmd/utils/flags.go

@@ -58,6 +58,7 @@ import (
 	"github.com/ethereum/go-ethereum/params"
 	whisper "github.com/ethereum/go-ethereum/whisper/whisperv6"
 	"gopkg.in/urfave/cli.v1"
+	"github.com/ethereum/go-ethereum/statediff"
 )
 
 var (
@@ -626,6 +627,12 @@ var (
 		Usage: "External EVM configuration (default = built-in interpreter)",
 		Value: "",
 	}
+
+	// Statediff flags
+	StateDiffFlag = cli.BoolFlag{
+		Name: "statediff",
+		Usage: "Enables the calculation of state diffs between each block, persists these state diffs in ipfs",
+	}
 )
 
 // MakeDataDir retrieves the currently requested data directory, terminating
@@ -1321,6 +1328,18 @@ func RegisterEthStatsService(stack *node.Node, url string) {
 	}
 }
 
+func RegisterStateDiffService(stack *node.Node) {
+	if err := stack.Register(func(ctx *node.ServiceContext) (node.Service, error) {
+		var ethServ *eth.Ethereum
+		ctx.Service(&ethServ)
+		chainDb := ethServ.ChainDb()
+		blockChain := ethServ.BlockChain()
+		return statediff.NewStateDiffService(chainDb, blockChain)
+	}); err != nil {
+		Fatalf("Failed to register State Diff Service", err)
+	}
+}
+
 func SetupMetrics(ctx *cli.Context) {
 	if metrics.Enabled {
 		log.Info("Enabling metrics collection")

core/blockchain.go

@@ -174,6 +174,7 @@ func NewBlockChain(db ethdb.Database, cacheConfig *CacheConfig, chainConfig *par
 	bc.SetProcessor(NewStateProcessor(chainConfig, bc, engine))
 
 	var err error
+
 	bc.hc, err = NewHeaderChain(db, chainConfig, engine, bc.getProcInterrupt)
 	if err != nil {
 		return nil, err
@@ -1187,6 +1188,7 @@ func (bc *BlockChain) insertChain(chain types.Blocks) (int, []interface{}, []*ty
 			parent = chain[i-1]
 		}
 		state, err := state.New(parent.Root(), bc.stateCache)
+
 		if err != nil {
 			return i, events, coalescedLogs, err
 		}

eth/backend.go

@@ -154,7 +154,12 @@ func New(ctx *node.ServiceContext, config *Config) (*Ethereum, error) {
 			EWASMInterpreter:        config.EWASMInterpreter,
 			EVMInterpreter:          config.EVMInterpreter,
 		}
-		cacheConfig = &core.CacheConfig{Disabled: config.NoPruning, TrieCleanLimit: config.TrieCleanCache, TrieDirtyLimit: config.TrieDirtyCache, TrieTimeLimit: config.TrieTimeout}
+		cacheConfig = &core.CacheConfig{
+			Disabled: config.NoPruning,
+			TrieCleanLimit: config.TrieCleanCache,
+			TrieDirtyLimit: config.TrieDirtyCache,
+			TrieTimeLimit: config.TrieTimeout,
+		}
 	)
 	eth.blockchain, err = core.NewBlockChain(chainDb, cacheConfig, eth.chainConfig, eth.engine, vmConfig, eth.shouldPreserve)
 	if err != nil {

statediff/builder/builder.go

@@ -0,0 +1,326 @@
+// Copyright 2015 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+// Contains a batch of utility type declarations used by the tests. As the node
+// operates on unique types, a lot of them are needed to check various features.
+
+package builder
+
+import (
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/core/state"
+	"github.com/ethereum/go-ethereum/ethdb"
+	"github.com/ethereum/go-ethereum/log"
+	"github.com/ethereum/go-ethereum/rlp"
+	"github.com/ethereum/go-ethereum/trie"
+)
+
+type Builder interface {
+	BuildStateDiff(oldStateRoot, newStateRoot common.Hash, blockNumber int64, blockHash common.Hash) (*StateDiff, error)
+}
+
+type builder struct {
+	chainDB    ethdb.Database
+	trieDB     *trie.Database
+	cachedTrie *trie.Trie
+}
+
+func NewBuilder(db ethdb.Database) *builder {
+	return &builder{
+		chainDB: db,
+		trieDB:  trie.NewDatabase(db),
+	}
+}
+
+func (sdb *builder) BuildStateDiff(oldStateRoot, newStateRoot common.Hash, blockNumber int64, blockHash common.Hash) (*StateDiff, error) {
+	// Generate tries for old and new states
+	oldTrie, err := trie.New(oldStateRoot, sdb.trieDB)
+	if err != nil {
+		log.Debug("error creating oldTrie", err)
+		//getting this error: error creating oldTrie missing trie node ddfbb83966d870891aa47147269447a83564d1defaefad5f9844a3a3a2a08433 (path )
+		return nil, err
+	}
+	newTrie, err := trie.New(newStateRoot, sdb.trieDB)
+	if err != nil {
+		log.Debug("error creating newTrie", err)
+		return nil, err
+	}
+
+	// Find created accounts
+	oldIt := oldTrie.NodeIterator([]byte{})
+	newIt := newTrie.NodeIterator([]byte{})
+	creations, err := sdb.collectDiffNodes(oldIt, newIt)
+	if err != nil {
+		log.Debug("error collecting creation diff nodes", err)
+		return nil, err
+	}
+
+	// Find deleted accounts
+	oldIt = oldTrie.NodeIterator(make([]byte, 0))
+	newIt = newTrie.NodeIterator(make([]byte, 0))
+	deletions, err := sdb.collectDiffNodes(newIt, oldIt)
+	if err != nil {
+		log.Debug("error collecting deletion diff nodes", err)
+		return nil, err
+	}
+
+	// Find all the diffed keys
+	createKeys := sortKeys(creations)
+	deleteKeys := sortKeys(deletions)
+	updatedKeys := findIntersection(createKeys, deleteKeys)
+
+	// Build and return the statediff
+	updatedAccounts, err := sdb.buildDiffIncremental(creations, deletions, updatedKeys)
+	if err != nil {
+		log.Debug("error building diff incremental for updated", err)
+		return nil, err
+	}
+	createdAccounts, err := sdb.buildDiffEventual(creations, true)
+	if err != nil {
+		log.Debug("error building diff incremental for created", err)
+		return nil, err
+	}
+	deletedAccounts, err := sdb.buildDiffEventual(deletions, false)
+	if err != nil {
+		log.Debug("error building diff incremental for deleted", err)
+		return nil, err
+	}
+
+	return &StateDiff{
+		BlockNumber:     blockNumber,
+		BlockHash:       blockHash,
+		CreatedAccounts: createdAccounts,
+		DeletedAccounts: deletedAccounts,
+		UpdatedAccounts: updatedAccounts,
+	}, nil
+}
+
+func (sdb *builder) collectDiffNodes(a, b trie.NodeIterator) (map[common.Address]*state.Account, error) {
+	var diffAccounts = make(map[common.Address]*state.Account)
+	it, _ := trie.NewDifferenceIterator(a, b)
+
+	for {
+		log.Debug("Current Path and Hash", "path", pathToStr(it), "hashold", common.Hash(it.Hash()))
+		if it.Leaf() {
+
+			// lookup address
+			path := make([]byte, len(it.Path())-1)
+			copy(path, it.Path())
+			addr, err := sdb.addressByPath(path)
+			if err != nil {
+				log.Error("Error looking up address via path", "path", path, "error", err)
+				return nil, err
+			}
+
+			// lookup account state
+			var account state.Account
+			if err := rlp.DecodeBytes(it.LeafBlob(), &account); err != nil {
+				log.Error("Error looking up account via address", "address", addr, "error", err)
+				return nil, err
+			}
+
+			// record account to diffs (creation if we are looking at new - old; deletion if old - new)
+			log.Debug("Account lookup successful", "address", addr, "account", account)
+			diffAccounts[*addr] = &account
+		}
+		cont := it.Next(true)
+		if !cont {
+			break
+		}
+	}
+
+	return diffAccounts, nil
+}
+
+func (sdb *builder) buildDiffEventual(accounts map[common.Address]*state.Account, created bool) (map[common.Address]AccountDiffEventual, error) {
+	accountDiffs := make(map[common.Address]AccountDiffEventual)
+	for addr, val := range accounts {
+		sr := val.Root
+		storageDiffs, err := sdb.buildStorageDiffsEventual(sr, created)
+		if err != nil {
+			log.Error("Failed building eventual storage diffs", "Address", val, "error", err)
+			return nil, err
+		}
+
+		codeBytes, err := sdb.chainDB.Get(val.CodeHash)
+
+		codeHash := common.ToHex(val.CodeHash)
+		hexRoot := val.Root.Hex()
+
+		if created {
+			nonce := DiffUint64{
+				NewValue: &val.Nonce,
+			}
+
+			balance := DiffBigInt{
+				NewValue: val.Balance,
+			}
+
+			contractRoot := DiffString{
+				NewValue: &hexRoot,
+			}
+			accountDiffs[addr] = AccountDiffEventual{
+				Nonce:        nonce,
+				Balance:      balance,
+				CodeHash:     codeHash,
+				Code:         codeBytes,
+				ContractRoot: contractRoot,
+				Storage:      storageDiffs,
+			}
+		} else {
+			nonce := DiffUint64{
+				OldValue: &val.Nonce,
+			}
+			balance := DiffBigInt{
+				OldValue: val.Balance,
+			}
+			contractRoot := DiffString{
+				OldValue: &hexRoot,
+			}
+			accountDiffs[addr] = AccountDiffEventual{
+				Nonce:        nonce,
+				Balance:      balance,
+				CodeHash:     codeHash,
+				ContractRoot: contractRoot,
+				Storage:      storageDiffs,
+			}
+		}
+	}
+
+	return accountDiffs, nil
+}
+
+func (sdb *builder) buildDiffIncremental(creations map[common.Address]*state.Account, deletions map[common.Address]*state.Account, updatedKeys []string) (map[common.Address]AccountDiffIncremental, error) {
+	updatedAccounts := make(map[common.Address]AccountDiffIncremental)
+	for _, val := range updatedKeys {
+		createdAcc := creations[common.HexToAddress(val)]
+		deletedAcc := deletions[common.HexToAddress(val)]
+		oldSR := deletedAcc.Root
+		newSR := createdAcc.Root
+		if storageDiffs, err := sdb.buildStorageDiffsIncremental(oldSR, newSR); err != nil {
+			log.Error("Failed building storage diffs", "Address", val, "error", err)
+			return nil, err
+		} else {
+			nonce := DiffUint64{
+				NewValue: &createdAcc.Nonce,
+				OldValue: &deletedAcc.Nonce,
+			}
+
+			balance := DiffBigInt{
+				NewValue: createdAcc.Balance,
+				OldValue: deletedAcc.Balance,
+			}
+			codeHash := common.ToHex(createdAcc.CodeHash)
+
+			nHexRoot := createdAcc.Root.Hex()
+			oHexRoot := deletedAcc.Root.Hex()
+			contractRoot := DiffString{
+				NewValue: &nHexRoot,
+				OldValue: &oHexRoot,
+			}
+
+			updatedAccounts[common.HexToAddress(val)] = AccountDiffIncremental{
+				Nonce:        nonce,
+				Balance:      balance,
+				CodeHash:     codeHash,
+				ContractRoot: contractRoot,
+				Storage:      storageDiffs,
+			}
+			delete(creations, common.HexToAddress(val))
+			delete(deletions, common.HexToAddress(val))
+		}
+	}
+	return updatedAccounts, nil
+}
+
+func (sdb *builder) buildStorageDiffsEventual(sr common.Hash, creation bool) (map[string]DiffString, error) {
+	log.Debug("Storage Root For Eventual Diff", "root", sr.Hex())
+	sTrie, err := trie.New(sr, sdb.trieDB)
+	if err != nil {
+		return nil, err
+	}
+	it := sTrie.NodeIterator(make([]byte, 0))
+	storageDiffs := make(map[string]DiffString)
+	for {
+		log.Debug("Iterating over state at path ", "path", pathToStr(it))
+		if it.Leaf() {
+			log.Debug("Found leaf in storage", "path", pathToStr(it))
+			path := pathToStr(it)
+			value := common.ToHex(it.LeafBlob())
+			if creation {
+				storageDiffs[path] = DiffString{NewValue: &value}
+			} else {
+				storageDiffs[path] = DiffString{OldValue: &value}
+			}
+		}
+		cont := it.Next(true)
+		if !cont {
+			break
+		}
+	}
+	return storageDiffs, nil
+}
+
+func (sdb *builder) buildStorageDiffsIncremental(oldSR common.Hash, newSR common.Hash) (map[string]DiffString, error) {
+	log.Debug("Storage Roots for Incremental Diff", "old", oldSR.Hex(), "new", newSR.Hex())
+	oldTrie, err := trie.New(oldSR, sdb.trieDB)
+	if err != nil {
+		return nil, err
+	}
+	newTrie, err := trie.New(newSR, sdb.trieDB)
+	if err != nil {
+		return nil, err
+	}
+
+	oldIt := oldTrie.NodeIterator(make([]byte, 0))
+	newIt := newTrie.NodeIterator(make([]byte, 0))
+	it, _ := trie.NewDifferenceIterator(oldIt, newIt)
+	storageDiffs := make(map[string]DiffString)
+	for {
+		if it.Leaf() {
+			log.Debug("Found leaf in storage", "path", pathToStr(it))
+			path := pathToStr(it)
+			value := common.ToHex(it.LeafBlob())
+			if oldVal, err := oldTrie.TryGet(it.LeafKey()); err != nil {
+				log.Error("Failed to look up value in oldTrie", "path", path, "error", err)
+			} else {
+				hexOldVal := common.ToHex(oldVal)
+				storageDiffs[path] = DiffString{OldValue: &hexOldVal, NewValue: &value}
+			}
+		}
+
+		cont := it.Next(true)
+		if !cont {
+			break
+		}
+	}
+	return storageDiffs, nil
+}
+
+func (sdb *builder) addressByPath(path []byte) (*common.Address, error) {
+	// db := core.PreimageTable(sdb.chainDb)
+	log.Debug("Looking up address from path", "path", common.ToHex(append([]byte("secure-key-"), path...)))
+	// if addrBytes,err := db.Get(path); err != nil {
+	if addrBytes, err := sdb.chainDB.Get(append([]byte("secure-key-"), hexToKeybytes(path)...)); err != nil {
+		log.Error("Error looking up address via path", "path", common.ToHex(append([]byte("secure-key-"), path...)), "error", err)
+		return nil, err
+	} else {
+		addr := common.BytesToAddress(addrBytes)
+		log.Debug("Address found", "Address", addr)
+		return &addr, nil
+	}
+
+}

statediff/builder/builder_suite_test.go

@@ -0,0 +1,32 @@
+// Copyright 2015 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+// Contains a batch of utility type declarations used by the tests. As the node
+// operates on unique types, a lot of them are needed to check various features.
+
+package builder_test
+
+import (
+	"testing"
+
+	. "github.com/onsi/ginkgo"
+	. "github.com/onsi/gomega"
+)
+
+func TestStateDiffBuilder(t *testing.T) {
+	RegisterFailHandler(Fail)
+	RunSpecs(t, "StateDiff Builder Suite")
+}

statediff/builder/builder_test.go

@@ -0,0 +1,322 @@
+// Copyright 2015 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+// Contains a batch of utility type declarations used by the tests. As the node
+// operates on unique types, a lot of them are needed to check various features.
+
+package builder_test
+
+import (
+	"math/big"
+
+	"github.com/onsi/ginkgo"
+	"github.com/onsi/gomega"
+
+	"github.com/ethereum/go-ethereum/ethdb"
+	"github.com/ethereum/go-ethereum/core"
+	"github.com/ethereum/go-ethereum/params"
+	"github.com/ethereum/go-ethereum/core/types"
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/consensus/ethash"
+	"github.com/ethereum/go-ethereum/crypto"
+	statediff "github.com/ethereum/go-ethereum/statediff/builder"
+)
+
+
+var (
+	testdb = ethdb.NewMemDatabase()
+
+	testBankKey, _  = crypto.HexToECDSA("b71c71a67e1177ad4e901695e1b4b9ee17ae16c6668d313eac2f96dbcda3f291")
+	testBankAddress = crypto.PubkeyToAddress(testBankKey.PublicKey) //0x71562b71999873DB5b286dF957af199Ec94617F7
+	testBankFunds   = big.NewInt(100000000)
+	genesis      = core.GenesisBlockForTesting(testdb, testBankAddress, testBankFunds)
+
+	account1Key, _ = crypto.HexToECDSA("8a1f9a8f95be41cd7ccb6168179afb4504aefe388d1e14474d32c45c72ce7b7a")
+	account2Key, _ = crypto.HexToECDSA("49a7b37aa6f6645917e7b807e9d1c00d4fa71f18343b0d4122a4d2df64dd6fee")
+	account1Addr   = crypto.PubkeyToAddress(account1Key.PublicKey) //0x703c4b2bD70c169f5717101CaeE543299Fc946C7
+	account2Addr   = crypto.PubkeyToAddress(account2Key.PublicKey) //0x0D3ab14BBaD3D99F4203bd7a11aCB94882050E7e
+
+	contractCode = common.Hex2Bytes("606060405260cc8060106000396000f360606040526000357c01000000000000000000000000000000000000000000000000000000009004806360cd2685146041578063c16431b914606b57603f565b005b6055600480803590602001909190505060a9565b6040518082815260200191505060405180910390f35b60886004808035906020019091908035906020019091905050608a565b005b80600060005083606481101560025790900160005b50819055505b5050565b6000600060005082606481101560025790900160005b5054905060c7565b91905056")
+	contractAddr common.Address
+
+	emptyAccountDiffEventualMap = make(map[common.Address]statediff.AccountDiffEventual)
+	emptyAccountDiffIncrementalMap = make(map[common.Address]statediff.AccountDiffIncremental)
+)
+/*
+contract test {
+
+    uint256[100] data;
+
+    function Put(uint256 addr, uint256 value) {
+        data[addr] = value;
+    }
+
+    function Get(uint256 addr) constant returns (uint256 value) {
+        return data[addr];
+    }
+}
+*/
+
+
+// makeChain creates a chain of n blocks starting at and including parent.
+// the returned hash chain is ordered head->parent. In addition, every 3rd block
+// contains a transaction and every 5th an uncle to allow testing correct block
+// reassembly.
+func makeChain(n int, seed byte, parent *types.Block) ([]common.Hash, map[common.Hash]*types.Block) {
+	blocks, _ := core.GenerateChain(params.TestChainConfig, parent, ethash.NewFaker(), testdb, n, testChainGen)
+	hashes := make([]common.Hash, n+1)
+	hashes[len(hashes)-1] = parent.Hash()
+	blockm := make(map[common.Hash]*types.Block, n+1)
+	blockm[parent.Hash()] = parent
+	for i, b := range blocks {
+		hashes[len(hashes)-i-2] = b.Hash()
+		blockm[b.Hash()] = b
+	}
+	return hashes, blockm
+}
+
+
+func testChainGen(i int, block *core.BlockGen) {
+	signer := types.HomesteadSigner{}
+	switch i {
+	case 0:
+		// In block 1, the test bank sends account #1 some ether.
+		tx, _ := types.SignTx(types.NewTransaction(block.TxNonce(testBankAddress), account1Addr, big.NewInt(10000), params.TxGas, nil, nil), signer, testBankKey)
+		block.AddTx(tx)
+	case 1:
+		// In block 2, the test bank sends some more ether to account #1.
+		// account1Addr passes it on to account #2.
+		// account1Addr creates a test contract.
+		tx1, _ := types.SignTx(types.NewTransaction(block.TxNonce(testBankAddress), account1Addr, big.NewInt(1000), params.TxGas, nil, nil), signer, testBankKey)
+		nonce := block.TxNonce(account1Addr)
+		tx2, _ := types.SignTx(types.NewTransaction(nonce, account2Addr, big.NewInt(1000), params.TxGas, nil, nil), signer, account1Key)
+		nonce++
+		tx3, _ := types.SignTx(types.NewContractCreation(nonce, big.NewInt(0), 1000000, big.NewInt(0), contractCode), signer, account1Key)
+		contractAddr = crypto.CreateAddress(account1Addr, nonce) //0xaE9BEa628c4Ce503DcFD7E305CaB4e29E7476592
+		block.AddTx(tx1)
+		block.AddTx(tx2)
+		block.AddTx(tx3)
+	case 2:
+		// Block 3 is empty but was mined by account #2.
+		block.SetCoinbase(account2Addr)
+		//get function: 60cd2685
+		//put function: c16431b9
+		data := common.Hex2Bytes("C16431B900000000000000000000000000000000000000000000000000000000000000020000000000000000000000000000000000000000000000000000000000000003")
+		tx, _ := types.SignTx(types.NewTransaction(block.TxNonce(testBankAddress), contractAddr, big.NewInt(0), 100000, nil, data), signer, testBankKey)
+		block.AddTx(tx)
+	}
+}
+var _ = ginkgo.FDescribe("", func() {
+	var (
+		block0Hash, block1Hash, block2Hash, block3Hash common.Hash
+		block0, block1, block2, block3 *types.Block
+		builder statediff.Builder
+		miningReward = int64(3000000000000000000)
+		burnAddress = common.HexToAddress("0x0")
+		diff *statediff.StateDiff
+		err error
+	)
+
+	ginkgo.BeforeEach(func() {
+		_, blocks := makeChain(3, 0, genesis)
+		block0Hash = common.HexToHash("0xd1721cfd0b29c36fd7a68f25c128e86413fb666a6e1d68e89b875bd299262661")
+		block1Hash = common.HexToHash("0x47c398dd688eaa4dd11b006888156783fe32df83d59b197c0fcd303408103d39")
+		block2Hash = common.HexToHash("0x351b2f531838683ba457e8ca4d3a844cc48147dceafbcb589dc6e3227856ee75")
+		block3Hash = common.HexToHash("0xfa40fbe2d98d98b3363a778d52f2bcd29d6790b9b3f3cab2b167fd12d3550f73")
+
+		block0 = blocks[block0Hash]
+		block1 = blocks[block1Hash]
+		block2 = blocks[block2Hash]
+		block3 = blocks[block3Hash]
+		builder = statediff.NewBuilder(testdb)
+	})
+
+	ginkgo.It("returns empty account diff collections when the state root hasn't changed", func() {
+		expectedDiff := statediff.StateDiff{
+			BlockNumber:     block0.Number().Int64(),
+			BlockHash:       block0Hash,
+			CreatedAccounts: emptyAccountDiffEventualMap,
+			DeletedAccounts: emptyAccountDiffEventualMap,
+			UpdatedAccounts: emptyAccountDiffIncrementalMap,
+		}
+
+		diff, err := builder.BuildStateDiff(block0.Root(), block0.Root(), block0.Number().Int64(), block0Hash)
+
+		gomega.Expect(err).NotTo(gomega.HaveOccurred())
+		gomega.Expect(diff).To(gomega.Equal(&expectedDiff))
+	})
+
+	ginkgo.Context("Block 1", func() {
+		//10000 transferred from testBankAddress to account1Addr
+		var balanceChange = int64(10000)
+
+		ginkgo.BeforeEach(func() {
+			diff, err = builder.BuildStateDiff(block0.Root(), block1.Root(), block1.Number().Int64(), block1Hash)
+
+			gomega.Expect(err).NotTo(gomega.HaveOccurred())
+		})
+
+		ginkgo.It("includes the block number and hash", func() {
+			gomega.Expect(diff.BlockNumber).To(gomega.Equal(block1.Number().Int64()))
+			gomega.Expect(diff.BlockHash).To(gomega.Equal(block1Hash))
+		})
+
+		ginkgo.It("returns an empty collection for deleted accounts", func() {
+			gomega.Expect(diff.DeletedAccounts).To(gomega.Equal(emptyAccountDiffEventualMap))
+		})
+
+		ginkgo.It("returns balance diffs for updated accounts", func() {
+			expectedBankBalanceDiff := statediff.DiffBigInt{
+				NewValue: big.NewInt(testBankFunds.Int64() - balanceChange),
+				OldValue: testBankFunds,
+			}
+
+			gomega.Expect(len(diff.UpdatedAccounts)).To(gomega.Equal(1))
+			gomega.Expect(diff.UpdatedAccounts[testBankAddress].Balance).To(gomega.Equal(expectedBankBalanceDiff))
+		})
+
+		ginkgo.It("returns balance diffs for new accounts", func() {
+			expectedAccount1BalanceDiff := statediff.DiffBigInt{
+				NewValue: big.NewInt(balanceChange),
+				OldValue: nil,
+			}
+
+			expectedBurnAddrBalanceDiff := statediff.DiffBigInt{
+				NewValue: big.NewInt(miningReward),
+				OldValue: nil,
+			}
+
+			gomega.Expect(len(diff.CreatedAccounts)).To(gomega.Equal(2))
+			gomega.Expect(diff.CreatedAccounts[account1Addr].Balance).To(gomega.Equal(expectedAccount1BalanceDiff))
+			gomega.Expect(diff.CreatedAccounts[burnAddress].Balance).To(gomega.Equal(expectedBurnAddrBalanceDiff))
+		})
+	})
+
+	ginkgo.Context("Block 2", func() {
+		//1000 transferred from testBankAddress to account1Addr
+		//1000 transferred from account1Addr to account2Addr
+		var (
+			balanceChange = int64(1000)
+			block1BankBalance = int64(99990000)
+			block1Account1Balance = int64(10000)
+		)
+
+		ginkgo.BeforeEach(func() {
+			diff, err = builder.BuildStateDiff(block1.Root(), block2.Root(), block2.Number().Int64(), block2Hash)
+
+			gomega.Expect(err).NotTo(gomega.HaveOccurred())
+		})
+
+		ginkgo.It("includes the block number and hash", func() {
+			gomega.Expect(diff.BlockNumber).To(gomega.Equal(block2.Number().Int64()))
+			gomega.Expect(diff.BlockHash).To(gomega.Equal(block2Hash))
+		})
+
+		ginkgo.It("returns an empty collection for deleted accounts", func() {
+			gomega.Expect(diff.DeletedAccounts).To(gomega.Equal(emptyAccountDiffEventualMap))
+		})
+
+		ginkgo.It("returns balance diffs for updated accounts", func() {
+			expectedBankBalanceDiff := statediff.DiffBigInt{
+				NewValue: big.NewInt(block1BankBalance - balanceChange),
+				OldValue: big.NewInt(block1BankBalance),
+			}
+
+			expectedAccount1BalanceDiff := statediff.DiffBigInt{
+				NewValue: big.NewInt(block1Account1Balance - balanceChange + balanceChange),
+				OldValue: big.NewInt(block1Account1Balance),
+			}
+
+			expectedBurnBalanceDiff := statediff.DiffBigInt{
+				NewValue: big.NewInt(miningReward + miningReward),
+				OldValue: big.NewInt(miningReward),
+			}
+
+			gomega.Expect(len(diff.UpdatedAccounts)).To(gomega.Equal(3))
+			gomega.Expect(diff.UpdatedAccounts[testBankAddress].Balance).To(gomega.Equal(expectedBankBalanceDiff))
+			gomega.Expect(diff.UpdatedAccounts[account1Addr].Balance).To(gomega.Equal(expectedAccount1BalanceDiff))
+			gomega.Expect(diff.UpdatedAccounts[burnAddress].Balance).To(gomega.Equal(expectedBurnBalanceDiff))
+		})
+
+		ginkgo.It("returns balance diffs for new accounts", func() {
+			expectedAccount2BalanceDiff := statediff.DiffBigInt{
+				NewValue: big.NewInt(balanceChange),
+				OldValue: nil,
+			}
+
+			expectedContractBalanceDiff := statediff.DiffBigInt{
+				NewValue: big.NewInt(0),
+				OldValue: nil,
+			}
+
+			gomega.Expect(len(diff.CreatedAccounts)).To(gomega.Equal(2))
+			gomega.Expect(diff.CreatedAccounts[account2Addr].Balance).To(gomega.Equal(expectedAccount2BalanceDiff))
+			gomega.Expect(diff.CreatedAccounts[contractAddr].Balance).To(gomega.Equal(expectedContractBalanceDiff))
+		})
+	})
+
+	ginkgo.Context("Block 3", func() {
+		//the contract's storage is changed
+		//and the block is mined by account 2
+		ginkgo.BeforeEach(func() {
+			diff, err = builder.BuildStateDiff(block2.Root(), block3.Root(), block3.Number().Int64(), block3Hash)
+
+			gomega.Expect(err).NotTo(gomega.HaveOccurred())
+		})
+
+		ginkgo.It("includes the block number and hash", func() {
+			gomega.Expect(diff.BlockNumber).To(gomega.Equal(block3.Number().Int64()))
+			gomega.Expect(diff.BlockHash).To(gomega.Equal(block3Hash))
+		})
+
+		ginkgo.It("returns an empty collection for deleted accounts", func() {
+			gomega.Expect(diff.DeletedAccounts).To(gomega.Equal(emptyAccountDiffEventualMap))
+		})
+
+		ginkgo.It("returns an empty collection for created accounts", func() {
+			gomega.Expect(diff.CreatedAccounts).To(gomega.Equal(emptyAccountDiffEventualMap))
+		})
+
+		ginkgo.It("returns balance, storage and nonce diffs for updated accounts", func() {
+			block2Account2Balance := int64(1000)
+			expectedAcct2BalanceDiff := statediff.DiffBigInt{
+				NewValue: big.NewInt(block2Account2Balance + miningReward),
+				OldValue: big.NewInt(block2Account2Balance),
+			}
+
+			expectedContractStorageDiff := make(map[string]statediff.DiffString)
+			newVal := "0x03"
+			oldVal := "0x0"
+			path := "0x405787fa12a823e0f2b7631cc41b3ba8828b3321ca811111fa75cd3aa3bb5ace"
+			expectedContractStorageDiff[path] = statediff.DiffString{
+				NewValue: &newVal,
+				OldValue: &oldVal,
+			}
+
+			oldNonce := uint64(2)
+			newNonce := uint64(3)
+			expectedBankNonceDiff := statediff.DiffUint64{
+				NewValue: &newNonce,
+				OldValue: &oldNonce,
+			}
+
+			gomega.Expect(len(diff.UpdatedAccounts)).To(gomega.Equal(3))
+			gomega.Expect(diff.UpdatedAccounts[account2Addr].Balance).To(gomega.Equal(expectedAcct2BalanceDiff))
+			gomega.Expect(diff.UpdatedAccounts[contractAddr].Storage).To(gomega.Equal(expectedContractStorageDiff))
+			gomega.Expect(diff.UpdatedAccounts[testBankAddress].Nonce).To(gomega.Equal(expectedBankNonceDiff))
+		})
+	})
+})

statediff/builder/helpers.go

@@ -0,0 +1,118 @@
+// Copyright 2015 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+// Contains a batch of utility type declarations used by the tests. As the node
+// operates on unique types, a lot of them are needed to check various features.
+
+package builder
+
+import (
+	"sort"
+	"strings"
+
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/core/state"
+	"github.com/ethereum/go-ethereum/trie"
+)
+
+func sortKeys(data map[common.Address]*state.Account) []string {
+	var keys []string
+	for key := range data {
+		keys = append(keys, key.Hex())
+	}
+	sort.Strings(keys)
+
+	return keys
+}
+
+func findIntersection(a, b []string) []string {
+	lenA := len(a)
+	lenB := len(b)
+	iOfA, iOfB := 0, 0
+	updates := make([]string, 0)
+	if iOfA >= lenA || iOfB >= lenB {
+		return updates
+	}
+	for {
+		switch strings.Compare(a[iOfA], b[iOfB]) {
+		// a[iOfA] < b[iOfB]
+		case -1:
+			iOfA++
+			if iOfA >= lenA {
+				return updates
+			}
+			break
+			// a[iOfA] == b[iOfB]
+		case 0:
+			updates = append(updates, a[iOfA])
+			iOfA++
+			iOfB++
+			if iOfA >= lenA || iOfB >= lenB {
+				return updates
+			}
+			break
+			// a[iOfA] > b[iOfB]
+		case 1:
+			iOfB++
+			if iOfB >= lenB {
+				return updates
+			}
+			break
+		}
+	}
+
+}
+
+func pathToStr(it trie.NodeIterator) string {
+	path := it.Path()
+	if hasTerm(path) {
+		path = path[:len(path)-1]
+	}
+	nibblePath := ""
+	for i, v := range common.ToHex(path) {
+		if i%2 == 0 && i > 1 {
+			continue
+		}
+		nibblePath = nibblePath + string(v)
+	}
+
+	return nibblePath
+}
+
+// Duplicated from trie/encoding.go
+func hexToKeybytes(hex []byte) []byte {
+	if hasTerm(hex) {
+		hex = hex[:len(hex)-1]
+	}
+	if len(hex)&1 != 0 {
+		panic("can't convert hex key of odd length")
+	}
+	key := make([]byte, (len(hex)+1)/2)
+	decodeNibbles(hex, key)
+
+	return key
+}
+
+func decodeNibbles(nibbles []byte, bytes []byte) {
+	for bi, ni := 0, 0; ni < len(nibbles); bi, ni = bi+1, ni+2 {
+		bytes[bi] = nibbles[ni]<<4 | nibbles[ni+1]
+	}
+}
+
+// hasTerm returns whether a hex key has the terminator flag.
+func hasTerm(s []byte) bool {
+	return len(s) > 0 && s[len(s)-1] == 16
+}

statediff/builder/struct.go

@@ -0,0 +1,86 @@
+// Copyright 2015 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+// Contains a batch of utility type declarations used by the tests. As the node
+// operates on unique types, a lot of them are needed to check various features.
+
+package builder
+
+import (
+	"encoding/json"
+	"math/big"
+
+	"github.com/ethereum/go-ethereum/common"
+)
+
+type StateDiff struct {
+	BlockNumber     int64                                     `json:"blockNumber"      gencodec:"required"`
+	BlockHash       common.Hash                               `json:"blockHash"        gencodec:"required"`
+	CreatedAccounts map[common.Address]AccountDiffEventual    `json:"createdAccounts"  gencodec:"required"`
+	DeletedAccounts map[common.Address]AccountDiffEventual    `json:"deletedAccounts"  gencodec:"required"`
+	UpdatedAccounts map[common.Address]AccountDiffIncremental `json:"updatedAccounts"  gencodec:"required"`
+
+	encoded []byte
+	err     error
+}
+
+func (self *StateDiff) ensureEncoded() {
+	if self.encoded == nil && self.err == nil {
+		self.encoded, self.err = json.Marshal(self)
+	}
+}
+
+// Implement Encoder interface for StateDiff
+func (sd *StateDiff) Length() int {
+	sd.ensureEncoded()
+	return len(sd.encoded)
+}
+
+// Implement Encoder interface for StateDiff
+func (sd *StateDiff) Encode() ([]byte, error) {
+	sd.ensureEncoded()
+	return sd.encoded, sd.err
+}
+
+type AccountDiffEventual struct {
+	Nonce        DiffUint64            `json:"nonce"         gencodec:"required"`
+	Balance      DiffBigInt            `json:"balance"       gencodec:"required"`
+	Code         []byte                `json:"code"          gencodec:"required"`
+	CodeHash     string                `json:"codeHash"      gencodec:"required"`
+	ContractRoot DiffString            `json:"contractRoot"  gencodec:"required"`
+	Storage      map[string]DiffString `json:"storage"       gencodec:"required"`
+}
+
+type AccountDiffIncremental struct {
+	Nonce        DiffUint64            `json:"nonce"         gencodec:"required"`
+	Balance      DiffBigInt            `json:"balance"       gencodec:"required"`
+	CodeHash     string                `json:"codeHash"      gencodec:"required"`
+	ContractRoot DiffString            `json:"contractRoot"  gencodec:"required"`
+	Storage      map[string]DiffString `json:"storage"       gencodec:"required"`
+}
+
+type DiffString struct {
+	NewValue *string `json:"newValue"  gencodec:"optional"`
+	OldValue *string `json:"oldValue"  gencodec:"optional"`
+}
+type DiffUint64 struct {
+	NewValue *uint64 `json:"newValue"  gencodec:"optional"`
+	OldValue *uint64 `json:"oldValue"  gencodec:"optional"`
+}
+type DiffBigInt struct {
+	NewValue *big.Int `json:"newValue"  gencodec:"optional"`
+	OldValue *big.Int `json:"oldValue"  gencodec:"optional"`
+}

statediff/config.go

@@ -0,0 +1,81 @@
+// Copyright 2015 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+// Contains a batch of utility type declarations used by the tests. As the node
+// operates on unique types, a lot of them are needed to check various features.
+
+package statediff
+
+import "fmt"
+
+type Config struct {
+	On   bool           // Whether or not to extract state diffs
+	Mode StateDiffMode  // Mode for storing diffs
+	Path string		    // Path for storing diffs
+}
+
+type StateDiffMode int
+
+const (
+	IPLD  StateDiffMode = iota
+	LDB
+	SQL
+)
+
+func (mode StateDiffMode) IsValid() bool {
+	return mode >= IPLD && mode <= SQL
+}
+
+// String implements the stringer interface.
+func (mode StateDiffMode) String() string {
+	switch mode {
+	case IPLD:
+		return "ipfs"
+	case LDB:
+		return "ldb"
+	case SQL:
+		return "sql"
+	default:
+		return "unknown"
+	}
+}
+
+func (mode StateDiffMode) MarshalText() ([]byte, error) {
+	switch mode {
+	case IPLD:
+		return []byte("ipfs"), nil
+	case LDB:
+		return []byte("ldb"), nil
+	case SQL:
+		return []byte("sql"), nil
+	default:
+		return nil, fmt.Errorf("unknown state diff storage mode %d", mode)
+	}
+}
+
+func (mode *StateDiffMode) UnmarshalText(text []byte) error {
+	switch string(text) {
+	case "ipfs":
+		*mode = IPLD
+	case "ldb":
+		*mode = LDB
+	case "sql":
+		*mode = SQL
+	default:
+		return fmt.Errorf(`unknown state diff storage mode %q, want "ipfs", "ldb" or "sql"`, text)
+	}
+	return nil
+}

statediff/extractor/extractor.go

@@ -0,0 +1,51 @@
+// Copyright 2015 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+// Contains a batch of utility type declarations used by the tests. As the node
+// operates on unique types, a lot of them are needed to check various features.
+
+package extractor
+
+import (
+	"github.com/ethereum/go-ethereum/core/types"
+	"github.com/ethereum/go-ethereum/statediff/builder"
+	"github.com/ethereum/go-ethereum/statediff/publisher"
+)
+
+type Extractor interface {
+	ExtractStateDiff(parent, current types.Block) (string, error)
+}
+
+type extractor struct {
+	Builder builder.Builder   // Interface for building state diff objects from two blocks
+	Publisher publisher.Publisher // Interface for publishing state diff objects to a datastore (e.g. IPFS)
+}
+
+func NewExtractor(b builder.Builder, p publisher.Publisher) (*extractor, error) {
+	return &extractor{
+		Builder:   b,
+		Publisher: p,
+	}, nil
+}
+
+func (e *extractor) ExtractStateDiff(parent, current types.Block) (string, error) {
+	stateDiff, err := e.Builder.BuildStateDiff(parent.Root(), current.Root(), current.Number().Int64(), current.Hash())
+	if err != nil {
+		return "", err
+	}
+
+	return e.Publisher.PublishStateDiff(stateDiff)
+}

statediff/extractor/extractor_suite_test.go

@@ -0,0 +1,32 @@
+// Copyright 2015 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+// Contains a batch of utility type declarations used by the tests. As the node
+// operates on unique types, a lot of them are needed to check various features.
+
+package extractor_test
+
+import (
+	"testing"
+
+	. "github.com/onsi/ginkgo"
+	. "github.com/onsi/gomega"
+)
+
+func TestStateDiffExtractor(t *testing.T) {
+	RegisterFailHandler(Fail)
+	RunSpecs(t, "StateDiff Extractor Suite")
+}

statediff/extractor/extractor_test.go

@@ -0,0 +1,102 @@
+// Copyright 2015 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+// Contains a batch of utility type declarations used by the tests. As the node
+// operates on unique types, a lot of them are needed to check various features.
+
+package extractor_test
+
+import (
+	"math/big"
+	"math/rand"
+
+	"github.com/onsi/ginkgo"
+	"github.com/onsi/gomega"
+
+	"github.com/ethereum/go-ethereum/statediff/extractor"
+	statediff "github.com/ethereum/go-ethereum/statediff/builder"
+	"github.com/ethereum/go-ethereum/core/types"
+	"github.com/ethereum/go-ethereum/statediff/testhelpers"
+)
+var _ = ginkgo.Describe("Extractor", func() {
+	var publisher testhelpers.MockPublisher
+	var builder testhelpers.MockBuilder
+	var currentBlockNumber *big.Int
+	var parentBlock, currentBlock *types.Block
+	var expectedStateDiff statediff.StateDiff
+	var ex extractor.Extractor
+	var err error
+
+	ginkgo.BeforeEach(func() {
+		publisher = testhelpers.MockPublisher{}
+		builder = testhelpers.MockBuilder{}
+		ex, err = extractor.NewExtractor(&builder, &publisher)
+		gomega.Expect(err).NotTo(gomega.HaveOccurred())
+
+		blockNumber := rand.Int63()
+		parentBlockNumber := big.NewInt(blockNumber - int64(1))
+		currentBlockNumber = big.NewInt(blockNumber)
+		parentBlock = types.NewBlock(&types.Header{Number: parentBlockNumber}, nil, nil, nil)
+		currentBlock = types.NewBlock(&types.Header{Number: currentBlockNumber}, nil, nil, nil)
+
+		expectedStateDiff = statediff.StateDiff{
+			BlockNumber:     blockNumber,
+			BlockHash:       currentBlock.Hash(),
+			CreatedAccounts: nil,
+			DeletedAccounts: nil,
+			UpdatedAccounts: nil,
+		}
+	})
+
+	ginkgo.It("builds a state diff struct", func() {
+		builder.SetStateDiffToBuild(&expectedStateDiff)
+
+		_, err = ex.ExtractStateDiff(*parentBlock, *currentBlock)
+
+		gomega.Expect(err).NotTo(gomega.HaveOccurred())
+		gomega.Expect(builder.OldStateRoot).To(gomega.Equal(parentBlock.Root()))
+		gomega.Expect(builder.NewStateRoot).To(gomega.Equal(currentBlock.Root()))
+		gomega.Expect(builder.BlockNumber).To(gomega.Equal(currentBlockNumber.Int64()))
+		gomega.Expect(builder.BlockHash).To(gomega.Equal(currentBlock.Hash()))
+	})
+
+	ginkgo.It("returns an error if building the state diff fails", func() {
+		builder.SetBuilderError(testhelpers.MockError)
+
+		_, err = ex.ExtractStateDiff(*parentBlock, *currentBlock)
+
+		gomega.Expect(err).To(gomega.HaveOccurred())
+		gomega.Expect(err).To(gomega.MatchError(testhelpers.MockError))
+	})
+
+	ginkgo.It("publishes the state diff struct", func() {
+		builder.SetStateDiffToBuild(&expectedStateDiff)
+
+		_, err = ex.ExtractStateDiff(*parentBlock, *currentBlock)
+
+		gomega.Expect(err).NotTo(gomega.HaveOccurred())
+		gomega.Expect(publisher.StateDiff).To(gomega.Equal(&expectedStateDiff))
+	})
+
+	ginkgo.It("returns an error if publishing the diff fails", func() {
+		publisher.SetPublisherError(testhelpers.MockError)
+
+		_, err = ex.ExtractStateDiff(*parentBlock, *currentBlock)
+
+		gomega.Expect(err).To(gomega.HaveOccurred())
+		gomega.Expect(err).To(gomega.MatchError(testhelpers.MockError))
+	})
+})

statediff/publisher/ipfs/adder.go

@@ -0,0 +1,58 @@
+// Copyright 2015 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+// Contains a batch of utility type declarations used by the tests. As the node
+// operates on unique types, a lot of them are needed to check various features.
+
+package ipfs
+
+import (
+	"context"
+
+	"github.com/ipfs/go-ipfs/core"
+	"github.com/ipfs/go-ipfs/repo/fsrepo"
+	ipld "gx/ipfs/QmcKKBwfz6FyQdHR2jsXrrF6XeSBXYL86anmWNewpFpoF5/go-ipld-format"
+)
+
+type Adder interface {
+	Add(node ipld.Node) error
+}
+
+type adder struct {
+	n   *core.IpfsNode
+	ctx context.Context
+}
+
+func (a adder) Add(node ipld.Node) error {
+	return a.n.DAG.Add(a.n.Context(), node) // For some reason DAG.Add method is not being exposed by the ipld.DAGService
+}
+
+func NewAdder(repoPath string) (*adder, error) {
+	r, err := fsrepo.Open(repoPath)
+	if err != nil {
+		return nil, err
+	}
+	ctx := context.Background()
+	cfg := &core.BuildCfg{
+		Online: false,
+		Repo:   r,
+	}
+	ipfsNode, err := core.NewNode(ctx, cfg)
+	if err != nil {
+		return nil, err
+	}
+	return &adder{n: ipfsNode, ctx: ctx}, nil
+}

statediff/publisher/ipfs/dag_putter.go

@@ -0,0 +1,80 @@
+// Copyright 2015 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+// Contains a batch of utility type declarations used by the tests. As the node
+// operates on unique types, a lot of them are needed to check various features.
+
+package ipfs
+
+import (
+	"bytes"
+	"encoding/gob"
+
+	ipld "gx/ipfs/QmcKKBwfz6FyQdHR2jsXrrF6XeSBXYL86anmWNewpFpoF5/go-ipld-format"
+
+	"github.com/ethereum/go-ethereum/statediff/builder"
+)
+
+const (
+	EthStateDiffCode = 0x99 // Register custom codec for state diff?
+)
+
+type DagPutter interface {
+	DagPut(sd *builder.StateDiff) (string, error)
+}
+
+type dagPutter struct {
+	Adder
+}
+
+func NewDagPutter(adder Adder) *dagPutter {
+	return &dagPutter{Adder: adder}
+}
+
+func (bhdp *dagPutter) DagPut(sd *builder.StateDiff) (string, error) {
+	nd, err := bhdp.getNode(sd)
+	if err != nil {
+		return "", err
+	}
+	err = bhdp.Add(nd)
+	if err != nil {
+		return "", err
+	}
+	return nd.Cid().String(), nil
+}
+
+func (bhdp *dagPutter) getNode(sd *builder.StateDiff) (ipld.Node, error) {
+
+	var buff bytes.Buffer
+	enc := gob.NewEncoder(&buff)
+
+	err := enc.Encode(sd)
+	if err != nil {
+		return nil, err
+	}
+
+	raw := buff.Bytes()
+	cid, err := RawToCid(EthStateDiffCode, raw)
+	if err != nil {
+		return nil, err
+	}
+
+	return &StateDiffNode{
+		StateDiff: sd,
+		cid:  cid,
+		rawdata: raw,
+	}, nil
+}

statediff/publisher/ipfs/helpers.go

@@ -0,0 +1,38 @@
+// Copyright 2015 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+// Contains a batch of utility type declarations used by the tests. As the node
+// operates on unique types, a lot of them are needed to check various features.
+
+package ipfs
+
+import (
+	mh "gx/ipfs/QmZyZDi491cCNTLfAhwcaDii2Kg4pwKRkhqQzURGDvY6ua/go-multihash"
+	"gx/ipfs/QmR8BauakNcBa3RbE4nbQu76PDiJgoQgz8AJdhJuiU4TAw/go-cid"
+)
+
+func RawToCid(codec uint64, raw []byte) (*cid.Cid, error) {
+	c, err := cid.Prefix{
+		Codec:    codec,
+		Version:  1,
+		MhType:   mh.KECCAK_256,
+		MhLength: -1,
+	}.Sum(raw)
+	if err != nil {
+		return nil, err
+	}
+	return &c, nil
+}

statediff/publisher/ipfs/node.go

@@ -0,0 +1,78 @@
+// Copyright 2015 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+// Contains a batch of utility type declarations used by the tests. As the node
+// operates on unique types, a lot of them are needed to check various features.
+
+package ipfs
+
+import (
+	"gx/ipfs/QmR8BauakNcBa3RbE4nbQu76PDiJgoQgz8AJdhJuiU4TAw/go-cid"
+	ipld "gx/ipfs/QmcKKBwfz6FyQdHR2jsXrrF6XeSBXYL86anmWNewpFpoF5/go-ipld-format"
+
+	"github.com/ethereum/go-ethereum/statediff/builder"
+)
+
+type StateDiffNode struct {
+	*builder.StateDiff
+
+	cid     *cid.Cid
+	rawdata []byte
+}
+
+func (sdn *StateDiffNode) RawData() []byte {
+	return sdn.rawdata
+}
+
+func (sdn *StateDiffNode) Cid() cid.Cid {
+	return *sdn.cid
+}
+
+func (sdn StateDiffNode) String() string {
+	return sdn.cid.String()
+}
+
+func (sdn StateDiffNode) Loggable() map[string]interface{} {
+	return sdn.cid.Loggable()
+}
+
+func (sdn StateDiffNode) Resolve(path []string) (interface{}, []string, error) {
+	panic("implement me")
+}
+
+func (sdn StateDiffNode) Tree(path string, depth int) []string {
+	panic("implement me")
+}
+
+func (sdn StateDiffNode) ResolveLink(path []string) (*ipld.Link, []string, error) {
+	panic("implement me")
+}
+
+func (sdn StateDiffNode) Copy() ipld.Node {
+	panic("implement me")
+}
+
+func (sdn StateDiffNode) Links() []*ipld.Link {
+	panic("implement me")
+}
+
+func (sdn StateDiffNode) Stat() (*ipld.NodeStat, error) {
+	panic("implement me")
+}
+
+func (sdn StateDiffNode) Size() (uint64, error) {
+	panic("implement me")
+}

statediff/publisher/publisher.go

@@ -0,0 +1,66 @@
+// Copyright 2015 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+// Contains a batch of utility type declarations used by the tests. As the node
+// operates on unique types, a lot of them are needed to check various features.
+
+package publisher
+
+import (
+	"errors"
+
+	"github.com/ethereum/go-ethereum/statediff"
+	"github.com/ethereum/go-ethereum/statediff/builder"
+	"github.com/ethereum/go-ethereum/statediff/publisher/ipfs"
+)
+
+type Publisher interface {
+	PublishStateDiff(sd *builder.StateDiff) (string, error)
+}
+
+type publisher struct {
+	ipfs.DagPutter
+	statediff.Config
+}
+
+func NewPublisher(config statediff.Config) (*publisher, error) {
+	adder, err := ipfs.NewAdder(config.Path)
+	if err != nil {
+		return nil, err
+	}
+
+	return &publisher{
+		DagPutter: ipfs.NewDagPutter(adder),
+		Config: config,
+	}, nil
+}
+
+func (p *publisher) PublishStateDiff(sd *builder.StateDiff) (string, error) {
+	switch p.Mode {
+	case statediff.IPLD:
+		cidStr, err := p.DagPut(sd)
+		if err != nil {
+			return "", err
+		}
+
+		return cidStr, err
+	case statediff.LDB:
+	case statediff.SQL:
+	default:
+	}
+
+	return "", errors.New("state diff publisher: unhandled publishing mode")
+}

statediff/publisher/publisher_suite_test.go

@@ -0,0 +1,32 @@
+// Copyright 2015 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+// Contains a batch of utility type declarations used by the tests. As the node
+// operates on unique types, a lot of them are needed to check various features.
+
+package publisher_test
+
+import (
+	"testing"
+
+	. "github.com/onsi/ginkgo"
+	. "github.com/onsi/gomega"
+)
+
+func TestStateDiffPublisher(t *testing.T) {
+	RegisterFailHandler(Fail)
+	RunSpecs(t, "StateDiff Publisher Suite")
+}

statediff/publisher/publisher_test.go

@@ -0,0 +1,20 @@
+// Copyright 2015 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+// Contains a batch of utility type declarations used by the tests. As the node
+// operates on unique types, a lot of them are needed to check various features.
+
+package publisher_test

statediff/service/service.go

@@ -0,0 +1,94 @@
+// Copyright 2015 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+// Contains a batch of utility type declarations used by the tests. As the node
+// operates on unique types, a lot of them are needed to check various features.
+
+package service
+
+import (
+	"log"
+
+	"github.com/ethereum/go-ethereum/core"
+	"github.com/ethereum/go-ethereum/ethdb"
+	"github.com/ethereum/go-ethereum/p2p"
+	"github.com/ethereum/go-ethereum/rpc"
+	"github.com/ethereum/go-ethereum/event"
+	"github.com/ethereum/go-ethereum/statediff"
+	"github.com/ethereum/go-ethereum/statediff/builder"
+	"github.com/ethereum/go-ethereum/statediff/extractor"
+	"github.com/ethereum/go-ethereum/statediff/publisher"
+)
+
+type StateDiffService struct {
+	builder    builder.Builder
+	extractor  extractor.Extractor
+	blockchain *core.BlockChain
+}
+
+func NewStateDiffService(db ethdb.Database, blockChain *core.BlockChain) (*StateDiffService, error) {
+	config := statediff.Config{}
+	b := builder.NewBuilder(db)
+	p, err := publisher.NewPublisher(config)
+	if err != nil {
+		return nil, nil
+	}
+
+	e, _ := extractor.NewExtractor(b, p)
+	return &StateDiffService{
+		blockchain: blockChain,
+		extractor:  e,
+	}, nil
+}
+
+func (StateDiffService) Protocols() []p2p.Protocol {
+	return []p2p.Protocol{}
+
+}
+
+func (StateDiffService) APIs() []rpc.API {
+	return []rpc.API{}
+}
+
+func (sds *StateDiffService) loop (sub event.Subscription, events chan core.ChainHeadEvent) {
+	defer sub.Unsubscribe()
+
+	for {
+		select {
+		case ev, ok := <-events:
+			if !ok {
+				log.Fatalf("Error getting chain head event from subscription.")
+			}
+			log.Println("doing something with an event", ev)
+		    previousBlock := ev.Block
+			//TODO: figure out the best way to get the previous block
+			currentBlock := ev.Block
+			sds.extractor.ExtractStateDiff(*previousBlock, *currentBlock)
+		}
+	}
+
+}
+func (sds *StateDiffService) Start(server *p2p.Server) error {
+	events := make(chan core.ChainHeadEvent, 10)
+	sub := sds.blockchain.SubscribeChainHeadEvent(events)
+
+	go sds.loop(sub, events)
+
+	return nil
+}
+func (StateDiffService) Stop() error {
+	return nil
+}

statediff/service/service_suite_test.go

@@ -0,0 +1,32 @@
+// Copyright 2015 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+// Contains a batch of utility type declarations used by the tests. As the node
+// operates on unique types, a lot of them are needed to check various features.
+
+package service_test
+
+import (
+	"testing"
+
+	. "github.com/onsi/ginkgo"
+	. "github.com/onsi/gomega"
+)
+
+func TestStateDiffService(t *testing.T) {
+	RegisterFailHandler(Fail)
+	RunSpecs(t, "StateDiff Service Suite")
+}

statediff/service/service_test.go

@@ -0,0 +1,20 @@
+// Copyright 2015 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+// Contains a batch of utility type declarations used by the tests. As the node
+// operates on unique types, a lot of them are needed to check various features.
+
+package service_test

statediff/statediff_integration_test.go

@@ -0,0 +1,20 @@
+// Copyright 2015 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+// Contains a batch of utility type declarations used by the tests. As the node
+// operates on unique types, a lot of them are needed to check various features.
+
+package statediff_test

statediff/statediff_suite_test.go

@@ -0,0 +1,32 @@
+// Copyright 2015 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+// Contains a batch of utility type declarations used by the tests. As the node
+// operates on unique types, a lot of them are needed to check various features.
+
+package statediff_test
+
+import (
+	"testing"
+
+	. "github.com/onsi/ginkgo"
+	. "github.com/onsi/gomega"
+)
+
+func TestStateDiff(t *testing.T) {
+	RegisterFailHandler(Fail)
+	RunSpecs(t, "StateDiff Suite")
+}

statediff/testhelpers/mocks.go

@@ -0,0 +1,68 @@
+// Copyright 2015 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+// Contains a batch of utility type declarations used by the tests. As the node
+// operates on unique types, a lot of them are needed to check various features.
+
+package testhelpers
+
+import (
+	"errors"
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/statediff/builder"
+)
+
+var MockError = errors.New("mock error")
+
+type MockBuilder struct {
+	OldStateRoot common.Hash
+	NewStateRoot common.Hash
+	BlockNumber int64
+	BlockHash common.Hash
+	stateDiff *builder.StateDiff
+	builderError error
+}
+
+func (builder *MockBuilder) BuildStateDiff(oldStateRoot, newStateRoot common.Hash, blockNumber int64, blockHash common.Hash) (*builder.StateDiff, error) {
+	builder.OldStateRoot = oldStateRoot
+	builder.NewStateRoot = newStateRoot
+	builder.BlockNumber = blockNumber
+	builder.BlockHash = blockHash
+
+	return builder.stateDiff, builder.builderError
+}
+
+func (builder *MockBuilder) SetStateDiffToBuild(stateDiff *builder.StateDiff) {
+	builder.stateDiff = stateDiff
+}
+
+func (builder *MockBuilder) SetBuilderError(err error) {
+	builder.builderError = err
+}
+
+type MockPublisher struct{
+	StateDiff *builder.StateDiff
+	publisherError error
+}
+
+func (publisher *MockPublisher) PublishStateDiff(sd *builder.StateDiff) (string, error) {
+	publisher.StateDiff = sd
+	return "", publisher.publisherError
+}
+
+func (publisher *MockPublisher) SetPublisherError(err error) {
+	publisher.publisherError = err
+}