Merge pull request #3402 from fjl/ethclient-api-fixes

eth/filters, ethclient, ethereum: API improvements

12 files changed, 327 insertions, 190 deletions

diff --git a/core/blockchain.go b/core/blockchain.go
index 2eb207d39..1f762d147 100644
--- a/core/blockchain.go
+++ b/core/blockchain.go
@@ -988,7 +988,7 @@ func (self *BlockChain) InsertChain(chain types.Blocks) (int, error) {
 				glog.Infof("inserted forked block #%d [%x…] (TD=%v) in %9v: %3d txs %d uncles.", block.Number(), block.Hash().Bytes()[0:4], block.Difficulty(), common.PrettyDuration(time.Since(bstart)), len(block.Transactions()), len(block.Uncles()))
 			}
 			blockInsertTimer.UpdateSince(bstart)
-			events = append(events, ChainSideEvent{block, logs})
+			events = append(events, ChainSideEvent{block})
 
 		case SplitStatTy:
 			events = append(events, ChainSplitEvent{block, logs})
@@ -1062,24 +1062,25 @@ func countTransactions(chain []*types.Block) (c int) {
 // event about them
 func (self *BlockChain) reorg(oldBlock, newBlock *types.Block) error {
 	var (
-		newChain          types.Blocks
-		oldChain          types.Blocks
-		commonBlock       *types.Block
-		oldStart          = oldBlock
-		newStart          = newBlock
-		deletedTxs        types.Transactions
-		deletedLogs       vm.Logs
-		deletedLogsByHash = make(map[common.Hash]vm.Logs)
+		newChain    types.Blocks
+		oldChain    types.Blocks
+		commonBlock *types.Block
+		oldStart    = oldBlock
+		newStart    = newBlock
+		deletedTxs  types.Transactions
+		deletedLogs vm.Logs
 		// collectLogs collects the logs that were generated during the
 		// processing of the block that corresponds with the given hash.
 		// These logs are later announced as deleted.
 		collectLogs = func(h common.Hash) {
-			// Coalesce logs
+			// Coalesce logs and set 'Removed'.
 			receipts := GetBlockReceipts(self.chainDb, h, self.hc.GetBlockNumber(h))
 			for _, receipt := range receipts {
-				deletedLogs = append(deletedLogs, receipt.Logs...)
-
-				deletedLogsByHash[h] = receipt.Logs
+				for _, log := range receipt.Logs {
+					del := *log
+					del.Removed = true
+					deletedLogs = append(deletedLogs, &del)
+				}
 			}
 		}
 	)
@@ -1173,7 +1174,7 @@ func (self *BlockChain) reorg(oldBlock, newBlock *types.Block) error {
 	if len(oldChain) > 0 {
 		go func() {
 			for _, block := range oldChain {
-				self.eventMux.Post(ChainSideEvent{Block: block, Logs: deletedLogsByHash[block.Hash()]})
+				self.eventMux.Post(ChainSideEvent{Block: block})
 			}
 		}()
 	}
diff --git a/core/events.go b/core/events.go
index 322bcb769..414493fbf 100644
--- a/core/events.go
+++ b/core/events.go
@@ -61,7 +61,6 @@ type ChainEvent struct {
 
 type ChainSideEvent struct {
 	Block *types.Block
-	Logs  vm.Logs
 }
 
 type PendingBlockEvent struct {
diff --git a/core/vm/log.go b/core/vm/log.go
index 06f941703..347bd6e5d 100644
--- a/core/vm/log.go
+++ b/core/vm/log.go
@@ -29,20 +29,42 @@ import (
 
 var errMissingLogFields = errors.New("missing required JSON log fields")
 
-// Log represents a contract log event. These events are generated by the LOG
-// opcode and stored/indexed by the node.
+// Log represents a contract log event. These events are generated by the LOG opcode and
+// stored/indexed by the node.
 type Log struct {
 	// Consensus fields.
 	Address common.Address // address of the contract that generated the event
 	Topics  []common.Hash  // list of topics provided by the contract.
 	Data    []byte         // supplied by the contract, usually ABI-encoded
 
-	// Derived fields (don't reorder!).
+	// Derived fields. These fields are filled in by the node
+	// but not secured by consensus.
 	BlockNumber uint64      // block in which the transaction was included
 	TxHash      common.Hash // hash of the transaction
 	TxIndex     uint        // index of the transaction in the block
 	BlockHash   common.Hash // hash of the block in which the transaction was included
 	Index       uint        // index of the log in the receipt
+
+	// The Removed field is true if this log was reverted due to a chain reorganisation.
+	// You must pay attention to this field if you receive logs through a filter query.
+	Removed bool
+}
+
+type rlpLog struct {
+	Address common.Address
+	Topics  []common.Hash
+	Data    []byte
+}
+
+type rlpStorageLog struct {
+	Address     common.Address
+	Topics      []common.Hash
+	Data        []byte
+	BlockNumber uint64
+	TxHash      common.Hash
+	TxIndex     uint
+	BlockHash   common.Hash
+	Index       uint
 }
 
 type jsonLog struct {
@@ -54,27 +76,26 @@ type jsonLog struct {
 	TxHash      *common.Hash    `json:"transactionHash"`
 	BlockHash   *common.Hash    `json:"blockHash"`
 	Index       *hexutil.Uint   `json:"logIndex"`
+	Removed     bool            `json:"removed"`
 }
 
 func NewLog(address common.Address, topics []common.Hash, data []byte, number uint64) *Log {
 	return &Log{Address: address, Topics: topics, Data: data, BlockNumber: number}
 }
 
+// EncodeRLP implements rlp.Encoder.
 func (l *Log) EncodeRLP(w io.Writer) error {
-	return rlp.Encode(w, []interface{}{l.Address, l.Topics, l.Data})
+	return rlp.Encode(w, rlpLog{Address: l.Address, Topics: l.Topics, Data: l.Data})
 }
 
+// DecodeRLP implements rlp.Decoder.
 func (l *Log) DecodeRLP(s *rlp.Stream) error {
-	var log struct {
-		Address common.Address
-		Topics  []common.Hash
-		Data    []byte
+	var dec rlpLog
+	err := s.Decode(&dec)
+	if err == nil {
+		l.Address, l.Topics, l.Data = dec.Address, dec.Topics, dec.Data
 	}
-	if err := s.Decode(&log); err != nil {
-		return err
-	}
-	l.Address, l.Topics, l.Data = log.Address, log.Topics, log.Data
-	return nil
+	return err
 }
 
 func (l *Log) String() string {
@@ -82,45 +103,88 @@ func (l *Log) String() string {
 }
 
 // MarshalJSON implements json.Marshaler.
-func (r *Log) MarshalJSON() ([]byte, error) {
-	return json.Marshal(&jsonLog{
-		Address:     &r.Address,
-		Topics:      &r.Topics,
-		Data:        (*hexutil.Bytes)(&r.Data),
-		BlockNumber: (*hexutil.Uint64)(&r.BlockNumber),
-		TxIndex:     (*hexutil.Uint)(&r.TxIndex),
-		TxHash:      &r.TxHash,
-		BlockHash:   &r.BlockHash,
-		Index:       (*hexutil.Uint)(&r.Index),
-	})
+func (l *Log) MarshalJSON() ([]byte, error) {
+	jslog := &jsonLog{
+		Address: &l.Address,
+		Topics:  &l.Topics,
+		Data:    (*hexutil.Bytes)(&l.Data),
+		TxIndex: (*hexutil.Uint)(&l.TxIndex),
+		TxHash:  &l.TxHash,
+		Index:   (*hexutil.Uint)(&l.Index),
+		Removed: l.Removed,
+	}
+	// Set block information for mined logs.
+	if (l.BlockHash != common.Hash{}) {
+		jslog.BlockHash = &l.BlockHash
+		jslog.BlockNumber = (*hexutil.Uint64)(&l.BlockNumber)
+	}
+	return json.Marshal(jslog)
 }
 
 // UnmarshalJSON implements json.Umarshaler.
-func (r *Log) UnmarshalJSON(input []byte) error {
+func (l *Log) UnmarshalJSON(input []byte) error {
 	var dec jsonLog
 	if err := json.Unmarshal(input, &dec); err != nil {
 		return err
 	}
-	if dec.Address == nil || dec.Topics == nil || dec.Data == nil || dec.BlockNumber == nil ||
-		dec.TxIndex == nil || dec.TxHash == nil || dec.BlockHash == nil || dec.Index == nil {
+	if dec.Address == nil || dec.Topics == nil || dec.Data == nil ||
+		dec.TxIndex == nil || dec.TxHash == nil || dec.Index == nil {
 		return errMissingLogFields
 	}
-	*r = Log{
-		Address:     *dec.Address,
-		Topics:      *dec.Topics,
-		Data:        *dec.Data,
-		BlockNumber: uint64(*dec.BlockNumber),
-		TxHash:      *dec.TxHash,
-		TxIndex:     uint(*dec.TxIndex),
-		BlockHash:   *dec.BlockHash,
-		Index:       uint(*dec.Index),
+	declog := Log{
+		Address: *dec.Address,
+		Topics:  *dec.Topics,
+		Data:    *dec.Data,
+		TxHash:  *dec.TxHash,
+		TxIndex: uint(*dec.TxIndex),
+		Index:   uint(*dec.Index),
+		Removed: dec.Removed,
+	}
+	// Block information may be missing if the log is received through
+	// the pending log filter, so it's handled specially here.
+	if dec.BlockHash != nil && dec.BlockNumber != nil {
+		declog.BlockHash = *dec.BlockHash
+		declog.BlockNumber = uint64(*dec.BlockNumber)
 	}
+	*l = declog
 	return nil
 }
 
 type Logs []*Log
 
-// LogForStorage is a wrapper around a Log that flattens and parses the entire
-// content of a log, as opposed to only the consensus fields originally (by hiding
-// the rlp interface methods).
+// LogForStorage is a wrapper around a Log that flattens and parses the entire content of
+// a log including non-consensus fields.
 type LogForStorage Log
+
+// EncodeRLP implements rlp.Encoder.
+func (l *LogForStorage) EncodeRLP(w io.Writer) error {
+	return rlp.Encode(w, rlpStorageLog{
+		Address:     l.Address,
+		Topics:      l.Topics,
+		Data:        l.Data,
+		BlockNumber: l.BlockNumber,
+		TxHash:      l.TxHash,
+		TxIndex:     l.TxIndex,
+		BlockHash:   l.BlockHash,
+		Index:       l.Index,
+	})
+}
+
+// DecodeRLP implements rlp.Decoder.
+func (l *LogForStorage) DecodeRLP(s *rlp.Stream) error {
+	var dec rlpStorageLog
+	err := s.Decode(&dec)
+	if err == nil {
+		*l = LogForStorage{
+			Address:     dec.Address,
+			Topics:      dec.Topics,
+			Data:        dec.Data,
+			BlockNumber: dec.BlockNumber,
+			TxHash:      dec.TxHash,
+			TxIndex:     dec.TxIndex,
+			BlockHash:   dec.BlockHash,
+			Index:       dec.Index,
+		}
+	}
+	return err
+}
diff --git a/core/vm/log_test.go b/core/vm/log_test.go
index 4d3189558..994753c62 100644
--- a/core/vm/log_test.go
+++ b/core/vm/log_test.go
@@ -18,18 +18,81 @@ package vm
 
 import (
 	"encoding/json"
+	"reflect"
 	"testing"
+
+	"github.com/davecgh/go-spew/spew"
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/common/hexutil"
 )
 
 var unmarshalLogTests = map[string]struct {
 	input     string
+	want      *Log
 	wantError error
 }{
 	"ok": {
-		input: `{"address":"0xecf8f87f810ecf450940c9f60066b4a7a501d6a7","blockHash":"0x656c34545f90a730a19008c0e7a7cd4fb3895064b48d6d69761bd5abad681056","blockNumber":"0x1ecfa4","data":"0x000000000000000000000000000000000000000000000001a055690d9db80000","logIndex":"0x2","topics":["0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef","0x00000000000000000000000080b2c9d7cbbf30a1b0fc8983c647d754c6525615","0x000000000000000000000000f9dff387dcb5cc4cca5b91adb07a95f54e9f1bb6"],"transactionHash":"0x3b198bfd5d2907285af009e9ae84a0ecd63677110d89d7e030251acb87f6487e","transactionIndex":"0x3"}`,
+		input: `{"address":"0xecf8f87f810ecf450940c9f60066b4a7a501d6a7","blockHash":"0x656c34545f90a730a19008c0e7a7cd4fb3895064b48d6d69761bd5abad681056","blockNumber":"0x1ecfa4","data":"0x000000000000000000000000000000000000000000000001a055690d9db80000","logIndex":"0x2","topics":["0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef","0x00000000000000000000000080b2c9d7cbbf30a1b0fc8983c647d754c6525615"],"transactionHash":"0x3b198bfd5d2907285af009e9ae84a0ecd63677110d89d7e030251acb87f6487e","transactionIndex":"0x3"}`,
+		want: &Log{
+			Address:     common.HexToAddress("0xecf8f87f810ecf450940c9f60066b4a7a501d6a7"),
+			BlockHash:   common.HexToHash("0x656c34545f90a730a19008c0e7a7cd4fb3895064b48d6d69761bd5abad681056"),
+			BlockNumber: 2019236,
+			Data:        hexutil.MustDecode("0x000000000000000000000000000000000000000000000001a055690d9db80000"),
+			Index:       2,
+			TxIndex:     3,
+			TxHash:      common.HexToHash("0x3b198bfd5d2907285af009e9ae84a0ecd63677110d89d7e030251acb87f6487e"),
+			Topics: []common.Hash{
+				common.HexToHash("0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef"),
+				common.HexToHash("0x00000000000000000000000080b2c9d7cbbf30a1b0fc8983c647d754c6525615"),
+			},
+		},
 	},
 	"empty data": {
-		input: `{"address":"0xecf8f87f810ecf450940c9f60066b4a7a501d6a7","blockHash":"0x656c34545f90a730a19008c0e7a7cd4fb3895064b48d6d69761bd5abad681056","blockNumber":"0x1ecfa4","data":"0x","logIndex":"0x2","topics":["0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef","0x00000000000000000000000080b2c9d7cbbf30a1b0fc8983c647d754c6525615","0x000000000000000000000000f9dff387dcb5cc4cca5b91adb07a95f54e9f1bb6"],"transactionHash":"0x3b198bfd5d2907285af009e9ae84a0ecd63677110d89d7e030251acb87f6487e","transactionIndex":"0x3"}`,
+		input: `{"address":"0xecf8f87f810ecf450940c9f60066b4a7a501d6a7","blockHash":"0x656c34545f90a730a19008c0e7a7cd4fb3895064b48d6d69761bd5abad681056","blockNumber":"0x1ecfa4","data":"0x","logIndex":"0x2","topics":["0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef","0x00000000000000000000000080b2c9d7cbbf30a1b0fc8983c647d754c6525615"],"transactionHash":"0x3b198bfd5d2907285af009e9ae84a0ecd63677110d89d7e030251acb87f6487e","transactionIndex":"0x3"}`,
+		want: &Log{
+			Address:     common.HexToAddress("0xecf8f87f810ecf450940c9f60066b4a7a501d6a7"),
+			BlockHash:   common.HexToHash("0x656c34545f90a730a19008c0e7a7cd4fb3895064b48d6d69761bd5abad681056"),
+			BlockNumber: 2019236,
+			Data:        []byte{},
+			Index:       2,
+			TxIndex:     3,
+			TxHash:      common.HexToHash("0x3b198bfd5d2907285af009e9ae84a0ecd63677110d89d7e030251acb87f6487e"),
+			Topics: []common.Hash{
+				common.HexToHash("0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef"),
+				common.HexToHash("0x00000000000000000000000080b2c9d7cbbf30a1b0fc8983c647d754c6525615"),
+			},
+		},
+	},
+	"missing block fields (pending logs)": {
+		input: `{"address":"0xecf8f87f810ecf450940c9f60066b4a7a501d6a7","data":"0x","logIndex":"0x0","topics":["0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef"],"transactionHash":"0x3b198bfd5d2907285af009e9ae84a0ecd63677110d89d7e030251acb87f6487e","transactionIndex":"0x3"}`,
+		want: &Log{
+			Address:     common.HexToAddress("0xecf8f87f810ecf450940c9f60066b4a7a501d6a7"),
+			BlockHash:   common.Hash{},
+			BlockNumber: 0,
+			Data:        []byte{},
+			Index:       0,
+			TxIndex:     3,
+			TxHash:      common.HexToHash("0x3b198bfd5d2907285af009e9ae84a0ecd63677110d89d7e030251acb87f6487e"),
+			Topics: []common.Hash{
+				common.HexToHash("0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef"),
+			},
+		},
+	},
+	"Removed: true": {
+		input: `{"address":"0xecf8f87f810ecf450940c9f60066b4a7a501d6a7","blockHash":"0x656c34545f90a730a19008c0e7a7cd4fb3895064b48d6d69761bd5abad681056","blockNumber":"0x1ecfa4","data":"0x","logIndex":"0x2","topics":["0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef"],"transactionHash":"0x3b198bfd5d2907285af009e9ae84a0ecd63677110d89d7e030251acb87f6487e","transactionIndex":"0x3","removed":true}`,
+		want: &Log{
+			Address:     common.HexToAddress("0xecf8f87f810ecf450940c9f60066b4a7a501d6a7"),
+			BlockHash:   common.HexToHash("0x656c34545f90a730a19008c0e7a7cd4fb3895064b48d6d69761bd5abad681056"),
+			BlockNumber: 2019236,
+			Data:        []byte{},
+			Index:       2,
+			TxIndex:     3,
+			TxHash:      common.HexToHash("0x3b198bfd5d2907285af009e9ae84a0ecd63677110d89d7e030251acb87f6487e"),
+			Topics: []common.Hash{
+				common.HexToHash("0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef"),
+			},
+			Removed: true,
+		},
 	},
 	"missing data": {
 		input:     `{"address":"0xecf8f87f810ecf450940c9f60066b4a7a501d6a7","blockHash":"0x656c34545f90a730a19008c0e7a7cd4fb3895064b48d6d69761bd5abad681056","blockNumber":"0x1ecfa4","logIndex":"0x2","topics":["0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef","0x00000000000000000000000080b2c9d7cbbf30a1b0fc8983c647d754c6525615","0x000000000000000000000000f9dff387dcb5cc4cca5b91adb07a95f54e9f1bb6"],"transactionHash":"0x3b198bfd5d2907285af009e9ae84a0ecd63677110d89d7e030251acb87f6487e","transactionIndex":"0x3"}`,
@@ -38,10 +101,16 @@ var unmarshalLogTests = map[string]struct {
 }
 
 func TestUnmarshalLog(t *testing.T) {
+	dumper := spew.ConfigState{DisableMethods: true, Indent: "    "}
 	for name, test := range unmarshalLogTests {
 		var log *Log
 		err := json.Unmarshal([]byte(test.input), &log)
 		checkError(t, name, err, test.wantError)
+		if test.wantError == nil && err == nil {
+			if !reflect.DeepEqual(log, test.want) {
+				t.Errorf("test %q:\nGOT %sWANT %s", name, dumper.Sdump(log), dumper.Sdump(test.want))
+			}
+		}
 	}
 }
 
diff --git a/eth/filters/api.go b/eth/filters/api.go
index d5dd57743..bbb34d3de 100644
--- a/eth/filters/api.go
+++ b/eth/filters/api.go
@@ -29,6 +29,7 @@ import (
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/common/hexutil"
 	"github.com/ethereum/go-ethereum/core/types"
+	"github.com/ethereum/go-ethereum/core/vm"
 	"github.com/ethereum/go-ethereum/ethdb"
 	"github.com/ethereum/go-ethereum/event"
 	"github.com/ethereum/go-ethereum/rpc"
@@ -45,7 +46,7 @@ type filter struct {
 	deadline *time.Timer // filter is inactiv when deadline triggers
 	hashes   []common.Hash
 	crit     FilterCriteria
-	logs     []Log
+	logs     []*vm.Log
 	s        *Subscription // associated subscription in event system
 }
 
@@ -241,7 +242,7 @@ func (api *PublicFilterAPI) Logs(ctx context.Context, crit FilterCriteria) (*rpc
 
 	var (
 		rpcSub      = notifier.CreateSubscription()
-		matchedLogs = make(chan []Log)
+		matchedLogs = make(chan []*vm.Log)
 	)
 
 	logsSub, err := api.events.SubscribeLogs(crit, matchedLogs)
@@ -292,14 +293,14 @@ type FilterCriteria struct {
 //
 // https://github.com/ethereum/wiki/wiki/JSON-RPC#eth_newfilter
 func (api *PublicFilterAPI) NewFilter(crit FilterCriteria) (rpc.ID, error) {
-	logs := make(chan []Log)
+	logs := make(chan []*vm.Log)
 	logsSub, err := api.events.SubscribeLogs(crit, logs)
 	if err != nil {
 		return rpc.ID(""), err
 	}
 
 	api.filtersMu.Lock()
-	api.filters[logsSub.ID] = &filter{typ: LogsSubscription, crit: crit, deadline: time.NewTimer(deadline), logs: make([]Log, 0), s: logsSub}
+	api.filters[logsSub.ID] = &filter{typ: LogsSubscription, crit: crit, deadline: time.NewTimer(deadline), logs: make([]*vm.Log, 0), s: logsSub}
 	api.filtersMu.Unlock()
 
 	go func() {
@@ -326,7 +327,7 @@ func (api *PublicFilterAPI) NewFilter(crit FilterCriteria) (rpc.ID, error) {
 // GetLogs returns logs matching the given argument that are stored within the state.
 //
 // https://github.com/ethereum/wiki/wiki/JSON-RPC#eth_getlogs
-func (api *PublicFilterAPI) GetLogs(ctx context.Context, crit FilterCriteria) ([]Log, error) {
+func (api *PublicFilterAPI) GetLogs(ctx context.Context, crit FilterCriteria) ([]*vm.Log, error) {
 	if crit.FromBlock == nil {
 		crit.FromBlock = big.NewInt(rpc.LatestBlockNumber.Int64())
 	}
@@ -365,7 +366,7 @@ func (api *PublicFilterAPI) UninstallFilter(id rpc.ID) bool {
 // If the filter could not be found an empty array of logs is returned.
 //
 // https://github.com/ethereum/wiki/wiki/JSON-RPC#eth_getfilterlogs
-func (api *PublicFilterAPI) GetFilterLogs(ctx context.Context, id rpc.ID) ([]Log, error) {
+func (api *PublicFilterAPI) GetFilterLogs(ctx context.Context, id rpc.ID) ([]*vm.Log, error) {
 	api.filtersMu.Lock()
 	f, found := api.filters[id]
 	api.filtersMu.Unlock()
@@ -388,7 +389,7 @@ func (api *PublicFilterAPI) GetFilterLogs(ctx context.Context, id rpc.ID) ([]Log
 	filter.SetAddresses(f.crit.Addresses)
 	filter.SetTopics(f.crit.Topics)
 
-	logs, err:= filter.Find(ctx)
+	logs, err := filter.Find(ctx)
 	if err != nil {
 		return nil, err
 	}
@@ -440,9 +441,9 @@ func returnHashes(hashes []common.Hash) []common.Hash {
 
 // returnLogs is a helper that will return an empty log array in case the given logs array is nil,
 // otherwise the given logs array is returned.
-func returnLogs(logs []Log) []Log {
+func returnLogs(logs []*vm.Log) []*vm.Log {
 	if logs == nil {
-		return []Log{}
+		return []*vm.Log{}
 	}
 	return logs
 }
diff --git a/eth/filters/filter.go b/eth/filters/filter.go
index ce7383fb3..a695d7eb7 100644
--- a/eth/filters/filter.go
+++ b/eth/filters/filter.go
@@ -25,6 +25,7 @@ import (
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/core"
 	"github.com/ethereum/go-ethereum/core/types"
+	"github.com/ethereum/go-ethereum/core/vm"
 	"github.com/ethereum/go-ethereum/ethdb"
 	"github.com/ethereum/go-ethereum/event"
 	"github.com/ethereum/go-ethereum/rpc"
@@ -38,7 +39,7 @@ type Backend interface {
 	GetReceipts(ctx context.Context, blockHash common.Hash) (types.Receipts, error)
 }
 
-// Filter can be used to retrieve and filter logs
+// Filter can be used to retrieve and filter logs.
 type Filter struct {
 	backend   Backend
 	useMipMap bool
@@ -85,7 +86,7 @@ func (f *Filter) SetTopics(topics [][]common.Hash) {
 }
 
 // Run filters logs with the current parameters set
-func (f *Filter) Find(ctx context.Context) ([]Log, error) {
+func (f *Filter) Find(ctx context.Context) ([]*vm.Log, error) {
 	head, _ := f.backend.HeaderByNumber(ctx, rpc.LatestBlockNumber)
 	if head == nil {
 		return nil, nil
@@ -110,7 +111,7 @@ func (f *Filter) Find(ctx context.Context) ([]Log, error) {
 	return f.mipFind(beginBlockNo, endBlockNo, 0), nil
 }
 
-func (f *Filter) mipFind(start, end uint64, depth int) (logs []Log) {
+func (f *Filter) mipFind(start, end uint64, depth int) (logs []*vm.Log) {
 	level := core.MIPMapLevels[depth]
 	// normalise numerator so we can work in level specific batches and
 	// work with the proper range checks
@@ -141,7 +142,7 @@ func (f *Filter) mipFind(start, end uint64, depth int) (logs []Log) {
 	return logs
 }
 
-func (f *Filter) getLogs(ctx context.Context, start, end uint64) (logs []Log, err error) {
+func (f *Filter) getLogs(ctx context.Context, start, end uint64) (logs []*vm.Log, err error) {
 	for i := start; i <= end; i++ {
 		header, err := f.backend.HeaderByNumber(ctx, rpc.BlockNumber(i))
 		if header == nil || err != nil {
@@ -156,13 +157,9 @@ func (f *Filter) getLogs(ctx context.Context, start, end uint64) (logs []Log, er
 			if err != nil {
 				return nil, err
 			}
-			var unfiltered []Log
+			var unfiltered []*vm.Log
 			for _, receipt := range receipts {
-				rl := make([]Log, len(receipt.Logs))
-				for i, l := range receipt.Logs {
-					rl[i] = Log{l, false}
-				}
-				unfiltered = append(unfiltered, rl...)
+				unfiltered = append(unfiltered, ([]*vm.Log)(receipt.Logs)...)
 			}
 			logs = append(logs, filterLogs(unfiltered, nil, nil, f.addresses, f.topics)...)
 		}
@@ -181,15 +178,15 @@ func includes(addresses []common.Address, a common.Address) bool {
 	return false
 }
 
-func filterLogs(logs []Log, fromBlock, toBlock *big.Int, addresses []common.Address, topics [][]common.Hash) []Log {
-	var ret []Log
-	// Filter the logs for interesting stuff
+// filterLogs creates a slice of logs matching the given criteria.
+func filterLogs(logs []*vm.Log, fromBlock, toBlock *big.Int, addresses []common.Address, topics [][]common.Hash) []*vm.Log {
+	var ret []*vm.Log
 Logs:
 	for _, log := range logs {
-		if fromBlock != nil && fromBlock.Int64() >= 0 && uint64(fromBlock.Int64()) > log.BlockNumber {
+		if fromBlock != nil && fromBlock.Int64() >= 0 && fromBlock.Uint64() > log.BlockNumber {
 			continue
 		}
-		if toBlock != nil && toBlock.Int64() >= 0 && uint64(toBlock.Int64()) < log.BlockNumber {
+		if toBlock != nil && toBlock.Int64() >= 0 && toBlock.Uint64() < log.BlockNumber {
 			continue
 		}
 
diff --git a/eth/filters/filter_system.go b/eth/filters/filter_system.go
index b59718aea..1b360cfdb 100644
--- a/eth/filters/filter_system.go
+++ b/eth/filters/filter_system.go
@@ -19,7 +19,6 @@
 package filters
 
 import (
-	"encoding/json"
 	"errors"
 	"fmt"
 	"sync"
@@ -60,42 +59,12 @@ var (
 	ErrInvalidSubscriptionID = errors.New("invalid id")
 )
 
-// Log is a helper that can hold additional information about vm.Log
-// necessary for the RPC interface.
-type Log struct {
-	*vm.Log
-	Removed bool `json:"removed"`
-}
-
-// MarshalJSON returns *l as the JSON encoding of l.
-func (l *Log) MarshalJSON() ([]byte, error) {
-	fields := map[string]interface{}{
-		"address":          l.Address,
-		"data":             fmt.Sprintf("0x%x", l.Data),
-		"blockNumber":      nil,
-		"logIndex":         fmt.Sprintf("%#x", l.Index),
-		"blockHash":        nil,
-		"transactionHash":  l.TxHash,
-		"transactionIndex": fmt.Sprintf("%#x", l.TxIndex),
-		"topics":           l.Topics,
-		"removed":          l.Removed,
-	}
-
-	// mined logs
-	if l.BlockHash != (common.Hash{}) {
-		fields["blockNumber"] = fmt.Sprintf("%#x", l.BlockNumber)
-		fields["blockHash"] = l.BlockHash
-	}
-
-	return json.Marshal(fields)
-}
-
 type subscription struct {
 	id        rpc.ID
 	typ       Type
 	created   time.Time
 	logsCrit  FilterCriteria
-	logs      chan []Log
+	logs      chan []*vm.Log
 	hashes    chan common.Hash
 	headers   chan *types.Header
 	installed chan struct{} // closed when the filter is installed
@@ -182,7 +151,7 @@ func (es *EventSystem) subscribe(sub *subscription) *Subscription {
 // SubscribeLogs creates a subscription that will write all logs matching the
 // given criteria to the given logs channel. Default value for the from and to
 // block is "latest". If the fromBlock > toBlock an error is returned.
-func (es *EventSystem) SubscribeLogs(crit FilterCriteria, logs chan []Log) (*Subscription, error) {
+func (es *EventSystem) SubscribeLogs(crit FilterCriteria, logs chan []*vm.Log) (*Subscription, error) {
 	var from, to rpc.BlockNumber
 	if crit.FromBlock == nil {
 		from = rpc.LatestBlockNumber
@@ -220,7 +189,7 @@ func (es *EventSystem) SubscribeLogs(crit FilterCriteria, logs chan []Log) (*Sub
 
 // subscribeMinedPendingLogs creates a subscription that returned mined and
 // pending logs that match the given criteria.
-func (es *EventSystem) subscribeMinedPendingLogs(crit FilterCriteria, logs chan []Log) *Subscription {
+func (es *EventSystem) subscribeMinedPendingLogs(crit FilterCriteria, logs chan []*vm.Log) *Subscription {
 	sub := &subscription{
 		id:        rpc.NewID(),
 		typ:       MinedAndPendingLogsSubscription,
@@ -238,7 +207,7 @@ func (es *EventSystem) subscribeMinedPendingLogs(crit FilterCriteria, logs chan
 
 // subscribeLogs creates a subscription that will write all logs matching the
 // given criteria to the given logs channel.
-func (es *EventSystem) subscribeLogs(crit FilterCriteria, logs chan []Log) *Subscription {
+func (es *EventSystem) subscribeLogs(crit FilterCriteria, logs chan []*vm.Log) *Subscription {
 	sub := &subscription{
 		id:        rpc.NewID(),
 		typ:       LogsSubscription,
@@ -256,7 +225,7 @@ func (es *EventSystem) subscribeLogs(crit FilterCriteria, logs chan []Log) *Subs
 
 // subscribePendingLogs creates a subscription that writes transaction hashes for
 // transactions that enter the transaction pool.
-func (es *EventSystem) subscribePendingLogs(crit FilterCriteria, logs chan []Log) *Subscription {
+func (es *EventSystem) subscribePendingLogs(crit FilterCriteria, logs chan []*vm.Log) *Subscription {
 	sub := &subscription{
 		id:        rpc.NewID(),
 		typ:       PendingLogsSubscription,
@@ -279,7 +248,7 @@ func (es *EventSystem) SubscribeNewHeads(headers chan *types.Header) *Subscripti
 		id:        rpc.NewID(),
 		typ:       BlocksSubscription,
 		created:   time.Now(),
-		logs:      make(chan []Log),
+		logs:      make(chan []*vm.Log),
 		hashes:    make(chan common.Hash),
 		headers:   headers,
 		installed: make(chan struct{}),
@@ -296,7 +265,7 @@ func (es *EventSystem) SubscribePendingTxEvents(hashes chan common.Hash) *Subscr
 		id:        rpc.NewID(),
 		typ:       PendingTransactionsSubscription,
 		created:   time.Now(),
-		logs:      make(chan []Log),
+		logs:      make(chan []*vm.Log),
 		hashes:    hashes,
 		headers:   make(chan *types.Header),
 		installed: make(chan struct{}),
@@ -319,7 +288,7 @@ func (es *EventSystem) broadcast(filters filterIndex, ev *event.Event) {
 		if len(e) > 0 {
 			for _, f := range filters[LogsSubscription] {
 				if ev.Time.After(f.created) {
-					if matchedLogs := filterLogs(convertLogs(e, false), f.logsCrit.FromBlock, f.logsCrit.ToBlock, f.logsCrit.Addresses, f.logsCrit.Topics); len(matchedLogs) > 0 {
+					if matchedLogs := filterLogs(e, f.logsCrit.FromBlock, f.logsCrit.ToBlock, f.logsCrit.Addresses, f.logsCrit.Topics); len(matchedLogs) > 0 {
 						f.logs <- matchedLogs
 					}
 				}
@@ -328,7 +297,7 @@ func (es *EventSystem) broadcast(filters filterIndex, ev *event.Event) {
 	case core.RemovedLogsEvent:
 		for _, f := range filters[LogsSubscription] {
 			if ev.Time.After(f.created) {
-				if matchedLogs := filterLogs(convertLogs(e.Logs, true), f.logsCrit.FromBlock, f.logsCrit.ToBlock, f.logsCrit.Addresses, f.logsCrit.Topics); len(matchedLogs) > 0 {
+				if matchedLogs := filterLogs(e.Logs, f.logsCrit.FromBlock, f.logsCrit.ToBlock, f.logsCrit.Addresses, f.logsCrit.Topics); len(matchedLogs) > 0 {
 					f.logs <- matchedLogs
 				}
 			}
@@ -336,7 +305,7 @@ func (es *EventSystem) broadcast(filters filterIndex, ev *event.Event) {
 	case core.PendingLogsEvent:
 		for _, f := range filters[PendingLogsSubscription] {
 			if ev.Time.After(f.created) {
-				if matchedLogs := filterLogs(convertLogs(e.Logs, false), nil, f.logsCrit.ToBlock, f.logsCrit.Addresses, f.logsCrit.Topics); len(matchedLogs) > 0 {
+				if matchedLogs := filterLogs(e.Logs, nil, f.logsCrit.ToBlock, f.logsCrit.Addresses, f.logsCrit.Topics); len(matchedLogs) > 0 {
 					f.logs <- matchedLogs
 				}
 			}
@@ -401,25 +370,22 @@ func (es *EventSystem) lightFilterNewHead(newHeader *types.Header, callBack func
 }
 
 // filter logs of a single header in light client mode
-func (es *EventSystem) lightFilterLogs(header *types.Header, addresses []common.Address, topics [][]common.Hash, remove bool) []Log {
-	//fmt.Println("lightFilterLogs", header.Number.Uint64(), remove)
+func (es *EventSystem) lightFilterLogs(header *types.Header, addresses []common.Address, topics [][]common.Hash, remove bool) []*vm.Log {
 	if bloomFilter(header.Bloom, addresses, topics) {
-		//fmt.Println("bloom match")
 		// Get the logs of the block
 		ctx, _ := context.WithTimeout(context.Background(), time.Second*5)
 		receipts, err := es.backend.GetReceipts(ctx, header.Hash())
 		if err != nil {
 			return nil
 		}
-		var unfiltered []Log
+		var unfiltered []*vm.Log
 		for _, receipt := range receipts {
-			rl := make([]Log, len(receipt.Logs))
-			for i, l := range receipt.Logs {
-				rl[i] = Log{l, remove}
+			for _, log := range receipt.Logs {
+				logcopy := *log
+				logcopy.Removed = remove
+				unfiltered = append(unfiltered, &logcopy)
 			}
-			unfiltered = append(unfiltered, rl...)
 		}
-
 		logs := filterLogs(unfiltered, nil, nil, addresses, topics)
 		return logs
 	}
@@ -465,13 +431,3 @@ func (es *EventSystem) eventLoop() {
 		}
 	}
 }
-
-// convertLogs is a helper utility that converts vm.Logs to []filter.Log.
-func convertLogs(in vm.Logs, removed bool) []Log {
-
-	logs := make([]Log, len(in))
-	for i, l := range in {
-		logs[i] = Log{l, removed}
-	}
-	return logs
-}
diff --git a/eth/filters/filter_system_test.go b/eth/filters/filter_system_test.go
index e8591a2e4..3ce0cf663 100644
--- a/eth/filters/filter_system_test.go
+++ b/eth/filters/filter_system_test.go
@@ -74,10 +74,10 @@ func TestBlockSubscription(t *testing.T) {
 	t.Parallel()
 
 	var (
-		mux   = new(event.TypeMux)
-		db, _ = ethdb.NewMemDatabase()
+		mux     = new(event.TypeMux)
+		db, _   = ethdb.NewMemDatabase()
 		backend = &testBackend{mux, db}
-		api   = NewPublicFilterAPI(backend, false)
+		api     = NewPublicFilterAPI(backend, false)
 
 		genesis     = core.WriteGenesisBlockForTesting(db)
 		chain, _    = core.GenerateChain(params.TestChainConfig, genesis, db, 10, func(i int, gen *core.BlockGen) {})
@@ -128,10 +128,10 @@ func TestPendingTxFilter(t *testing.T) {
 	t.Parallel()
 
 	var (
-		mux   = new(event.TypeMux)
-		db, _ = ethdb.NewMemDatabase()
+		mux     = new(event.TypeMux)
+		db, _   = ethdb.NewMemDatabase()
 		backend = &testBackend{mux, db}
-		api   = NewPublicFilterAPI(backend, false)
+		api     = NewPublicFilterAPI(backend, false)
 
 		transactions = []*types.Transaction{
 			types.NewTransaction(0, common.HexToAddress("0xb794f5ea0ba39494ce83a213fffba74279579268"), new(big.Int), new(big.Int), new(big.Int), nil),
@@ -178,10 +178,10 @@ func TestPendingTxFilter(t *testing.T) {
 // If not it must return an error.
 func TestLogFilterCreation(t *testing.T) {
 	var (
-		mux   = new(event.TypeMux)
-		db, _ = ethdb.NewMemDatabase()
+		mux     = new(event.TypeMux)
+		db, _   = ethdb.NewMemDatabase()
 		backend = &testBackend{mux, db}
-		api   = NewPublicFilterAPI(backend, false)
+		api     = NewPublicFilterAPI(backend, false)
 
 		testCases = []struct {
 			crit    FilterCriteria
@@ -223,10 +223,10 @@ func TestInvalidLogFilterCreation(t *testing.T) {
 	t.Parallel()
 
 	var (
-		mux   = new(event.TypeMux)
-		db, _ = ethdb.NewMemDatabase()
+		mux     = new(event.TypeMux)
+		db, _   = ethdb.NewMemDatabase()
 		backend = &testBackend{mux, db}
-		api   = NewPublicFilterAPI(backend, false)
+		api     = NewPublicFilterAPI(backend, false)
 	)
 
 	// different situations where log filter creation should fail.
@@ -249,10 +249,10 @@ func TestLogFilter(t *testing.T) {
 	t.Parallel()
 
 	var (
-		mux   = new(event.TypeMux)
-		db, _ = ethdb.NewMemDatabase()
+		mux     = new(event.TypeMux)
+		db, _   = ethdb.NewMemDatabase()
 		backend = &testBackend{mux, db}
-		api   = NewPublicFilterAPI(backend, false)
+		api     = NewPublicFilterAPI(backend, false)
 
 		firstAddr      = common.HexToAddress("0x1111111111111111111111111111111111111111")
 		secondAddr     = common.HexToAddress("0x2222222222222222222222222222222222222222")
@@ -321,14 +321,14 @@ func TestLogFilter(t *testing.T) {
 	}
 
 	for i, tt := range testCases {
-		var fetched []Log
+		var fetched []*vm.Log
 		for { // fetch all expected logs
 			results, err := api.GetFilterChanges(tt.id)
 			if err != nil {
 				t.Fatalf("Unable to fetch logs: %v", err)
 			}
 
-			fetched = append(fetched, results.([]Log)...)
+			fetched = append(fetched, results.([]*vm.Log)...)
 			if len(fetched) >= len(tt.expected) {
 				break
 			}
@@ -345,7 +345,7 @@ func TestLogFilter(t *testing.T) {
 			if fetched[l].Removed {
 				t.Errorf("expected log not to be removed for log %d in case %d", l, i)
 			}
-			if !reflect.DeepEqual(fetched[l].Log, tt.expected[l]) {
+			if !reflect.DeepEqual(fetched[l], tt.expected[l]) {
 				t.Errorf("invalid log on index %d for case %d", l, i)
 			}
 		}
@@ -357,10 +357,10 @@ func TestPendingLogsSubscription(t *testing.T) {
 	t.Parallel()
 
 	var (
-		mux   = new(event.TypeMux)
-		db, _ = ethdb.NewMemDatabase()
+		mux     = new(event.TypeMux)
+		db, _   = ethdb.NewMemDatabase()
 		backend = &testBackend{mux, db}
-		api   = NewPublicFilterAPI(backend, false)
+		api     = NewPublicFilterAPI(backend, false)
 
 		firstAddr      = common.HexToAddress("0x1111111111111111111111111111111111111111")
 		secondAddr     = common.HexToAddress("0x2222222222222222222222222222222222222222")
@@ -397,7 +397,7 @@ func TestPendingLogsSubscription(t *testing.T) {
 		testCases = []struct {
 			crit     FilterCriteria
 			expected vm.Logs
-			c        chan []Log
+			c        chan []*vm.Log
 			sub      *Subscription
 		}{
 			// match all
@@ -423,7 +423,7 @@ func TestPendingLogsSubscription(t *testing.T) {
 	// on slow machines this could otherwise lead to missing events when the subscription is created after
 	// (some) events are posted.
 	for i := range testCases {
-		testCases[i].c = make(chan []Log)
+		testCases[i].c = make(chan []*vm.Log)
 		testCases[i].sub, _ = api.events.SubscribeLogs(testCases[i].crit, testCases[i].c)
 	}
 
@@ -431,7 +431,7 @@ func TestPendingLogsSubscription(t *testing.T) {
 		i := n
 		tt := test
 		go func() {
-			var fetched []Log
+			var fetched []*vm.Log
 		fetchLoop:
 			for {
 				logs := <-tt.c
@@ -449,7 +449,7 @@ func TestPendingLogsSubscription(t *testing.T) {
 				if fetched[l].Removed {
 					t.Errorf("expected log not to be removed for log %d in case %d", l, i)
 				}
-				if !reflect.DeepEqual(fetched[l].Log, tt.expected[l]) {
+				if !reflect.DeepEqual(fetched[l], tt.expected[l]) {
 					t.Errorf("invalid log on index %d for case %d", l, i)
 				}
 			}
diff --git a/ethclient/ethclient.go b/ethclient/ethclient.go
index 00edd90e1..4daebda92 100644
--- a/ethclient/ethclient.go
+++ b/ethclient/ethclient.go
@@ -81,6 +81,8 @@ func (ec *Client) getBlock(ctx context.Context, method string, args ...interface
 	err := ec.c.CallContext(ctx, &raw, method, args...)
 	if err != nil {
 		return nil, err
+	} else if len(raw) == 0 {
+		return nil, ethereum.NotFound
 	}
 	// Decode header and transactions.
 	var head *types.Header
@@ -112,7 +114,7 @@ func (ec *Client) getBlock(ctx context.Context, method string, args ...interface
 		for i := range reqs {
 			reqs[i] = rpc.BatchElem{
 				Method: "eth_getUncleByBlockHashAndIndex",
-				Args:   []interface{}{body.Hash, fmt.Sprintf("%#x", i)},
+				Args:   []interface{}{body.Hash, hexutil.EncodeUint64(uint64(i))},
 				Result: &uncles[i],
 			}
 		}
@@ -123,6 +125,9 @@ func (ec *Client) getBlock(ctx context.Context, method string, args ...interface
 			if reqs[i].Error != nil {
 				return nil, reqs[i].Error
 			}
+			if uncles[i] == nil {
+				return nil, fmt.Errorf("got null header for uncle %d of block %x", i, body.Hash[:])
+			}
 		}
 	}
 	return types.NewBlockWithHeader(head).WithBody(body.Transactions, uncles), nil
@@ -132,6 +137,9 @@ func (ec *Client) getBlock(ctx context.Context, method string, args ...interface
 func (ec *Client) HeaderByHash(ctx context.Context, hash common.Hash) (*types.Header, error) {
 	var head *types.Header
 	err := ec.c.CallContext(ctx, &head, "eth_getBlockByHash", hash, false)
+	if err == nil && head == nil {
+		err = ethereum.NotFound
+	}
 	return head, err
 }
 
@@ -140,19 +148,31 @@ func (ec *Client) HeaderByHash(ctx context.Context, hash common.Hash) (*types.He
 func (ec *Client) HeaderByNumber(ctx context.Context, number *big.Int) (*types.Header, error) {
 	var head *types.Header
 	err := ec.c.CallContext(ctx, &head, "eth_getBlockByNumber", toBlockNumArg(number), false)
+	if err == nil && head == nil {
+		err = ethereum.NotFound
+	}
 	return head, err
 }
 
 // TransactionByHash returns the transaction with the given hash.
-func (ec *Client) TransactionByHash(ctx context.Context, hash common.Hash) (*types.Transaction, error) {
-	var tx *types.Transaction
-	err := ec.c.CallContext(ctx, &tx, "eth_getTransactionByHash", hash)
-	if err == nil {
-		if _, r, _ := tx.RawSignatureValues(); r == nil {
-			return nil, fmt.Errorf("server returned transaction without signature")
-		}
+func (ec *Client) TransactionByHash(ctx context.Context, hash common.Hash) (tx *types.Transaction, isPending bool, err error) {
+	var raw json.RawMessage
+	err = ec.c.CallContext(ctx, &raw, "eth_getTransactionByHash", hash)
+	if err != nil {
+		return nil, false, err
+	} else if len(raw) == 0 {
+		return nil, false, ethereum.NotFound
 	}
-	return tx, err
+	if err := json.Unmarshal(raw, tx); err != nil {
+		return nil, false, err
+	} else if _, r, _ := tx.RawSignatureValues(); r == nil {
+		return nil, false, fmt.Errorf("server returned transaction without signature")
+	}
+	var block struct{ BlockHash *common.Hash }
+	if err := json.Unmarshal(raw, &block); err != nil {
+		return nil, false, err
+	}
+	return tx, block.BlockHash == nil, nil
 }
 
 // TransactionCount returns the total number of transactions in the given block.
@@ -167,11 +187,9 @@ func (ec *Client) TransactionInBlock(ctx context.Context, blockHash common.Hash,
 	var tx *types.Transaction
 	err := ec.c.CallContext(ctx, &tx, "eth_getTransactionByBlockHashAndIndex", blockHash, index)
 	if err == nil {
-		var signer types.Signer = types.HomesteadSigner{}
-		if tx.Protected() {
-			signer = types.NewEIP155Signer(tx.ChainId())
-		}
-		if _, r, _ := types.SignatureValues(signer, tx); r == nil {
+		if tx == nil {
+			return nil, ethereum.NotFound
+		} else if _, r, _ := tx.RawSignatureValues(); r == nil {
 			return nil, fmt.Errorf("server returned transaction without signature")
 		}
 	}
@@ -183,8 +201,12 @@ func (ec *Client) TransactionInBlock(ctx context.Context, blockHash common.Hash,
 func (ec *Client) TransactionReceipt(ctx context.Context, txHash common.Hash) (*types.Receipt, error) {
 	var r *types.Receipt
 	err := ec.c.CallContext(ctx, &r, "eth_getTransactionReceipt", txHash)
-	if err == nil && r != nil && len(r.PostState) == 0 {
-		return nil, fmt.Errorf("server returned receipt without post state")
+	if err == nil {
+		if r == nil {
+			return nil, ethereum.NotFound
+		} else if len(r.PostState) == 0 {
+			return nil, fmt.Errorf("server returned receipt without post state")
+		}
 	}
 	return r, err
 }
@@ -193,7 +215,7 @@ func toBlockNumArg(number *big.Int) string {
 	if number == nil {
 		return "latest"
 	}
-	return fmt.Sprintf("%#x", number)
+	return hexutil.EncodeBig(number)
 }
 
 type rpcProgress struct {
diff --git a/ethclient/ethclient_test.go b/ethclient/ethclient_test.go
index 102c0d3b2..178eb2be9 100644
--- a/ethclient/ethclient_test.go
+++ b/ethclient/ethclient_test.go
@@ -21,9 +21,9 @@ import "github.com/ethereum/go-ethereum"
 // Verify that Client implements the ethereum interfaces.
 var (
 	_ = ethereum.ChainReader(&Client{})
+	_ = ethereum.TransactionReader(&Client{})
 	_ = ethereum.ChainStateReader(&Client{})
 	_ = ethereum.ChainSyncReader(&Client{})
-	_ = ethereum.ChainHeadEventer(&Client{})
 	_ = ethereum.ContractCaller(&Client{})
 	_ = ethereum.GasEstimator(&Client{})
 	_ = ethereum.GasPricer(&Client{})
diff --git a/interfaces.go b/interfaces.go
index aab0e2029..bbb204ff2 100644
--- a/interfaces.go
+++ b/interfaces.go
@@ -18,6 +18,7 @@
 package ethereum
 
 import (
+	"errors"
 	"math/big"
 
 	"github.com/ethereum/go-ethereum/common"
@@ -26,6 +27,9 @@ import (
 	"golang.org/x/net/context"
 )
 
+// NotFound is returned by API methods if the requested item does not exist.
+var NotFound = errors.New("not found")
+
 // TODO: move subscription to package event
 
 // Subscription represents an event subscription where events are
@@ -46,6 +50,8 @@ type Subscription interface {
 // blockchain fork that was previously downloaded and processed by the node. The block
 // number argument can be nil to select the latest canonical block. Reading block headers
 // should be preferred over full blocks whenever possible.
+//
+// The returned error is NotFound if the requested item does not exist.
 type ChainReader interface {
 	BlockByHash(ctx context.Context, hash common.Hash) (*types.Block, error)
 	BlockByNumber(ctx context.Context, number *big.Int) (*types.Block, error)
@@ -53,7 +59,30 @@ type ChainReader interface {
 	HeaderByNumber(ctx context.Context, number *big.Int) (*types.Header, error)
 	TransactionCount(ctx context.Context, blockHash common.Hash) (uint, error)
 	TransactionInBlock(ctx context.Context, blockHash common.Hash, index uint) (*types.Transaction, error)
-	TransactionByHash(ctx context.Context, txHash common.Hash) (*types.Transaction, error)
+
+	// This method subscribes to notifications about changes of the head block of
+	// the canonical chain.
+	SubscribeNewHead(ctx context.Context, ch chan<- *types.Header) (Subscription, error)
+}
+
+// TransactionReader provides access to past transactions and their receipts.
+// Implementations may impose arbitrary restrictions on the transactions and receipts that
+// can be retrieved. Historic transactions may not be available.
+//
+// Avoid relying on this interface if possible. Contract logs (through the LogFilterer
+// interface) are more reliable and usually safer in the presence of chain
+// reorganisations.
+//
+// The returned error is NotFound if the requested item does not exist.
+type TransactionReader interface {
+	// TransactionByHash checks the pool of pending transactions in addition to the
+	// blockchain. The isPending return value indicates whether the transaction has been
+	// mined yet. Note that the transaction may not be part of the canonical chain even if
+	// it's not pending.
+	TransactionByHash(ctx context.Context, txHash common.Hash) (tx *types.Transaction, isPending bool, err error)
+	// TransactionReceipt returns the receipt of a mined transaction. Note that the
+	// transaction may not be included in the current canonical chain even if a receipt
+	// exists.
 	TransactionReceipt(ctx context.Context, txHash common.Hash) (*types.Receipt, error)
 }
 
@@ -83,11 +112,6 @@ type ChainSyncReader interface {
 	SyncProgress(ctx context.Context) (*SyncProgress, error)
 }
 
-// A ChainHeadEventer returns notifications whenever the canonical head block is updated.
-type ChainHeadEventer interface {
-	SubscribeNewHead(ctx context.Context, ch chan<- *types.Header) (Subscription, error)
-}
-
 // CallMsg contains parameters for contract calls.
 type CallMsg struct {
 	From     common.Address  // the sender of the 'transaction'
@@ -128,6 +152,9 @@ type FilterQuery struct {
 
 // LogFilterer provides access to contract log events using a one-off query or continuous
 // event subscription.
+//
+// Logs received through a streaming query subscription may have Removed set to true,
+// indicating that the log was reverted due to a chain reorganisation.
 type LogFilterer interface {
 	FilterLogs(ctx context.Context, q FilterQuery) ([]vm.Log, error)
 	SubscribeFilterLogs(ctx context.Context, q FilterQuery, ch chan<- vm.Log) (Subscription, error)
diff --git a/mobile/ethclient.go b/mobile/ethclient.go
index 668d65e32..a60fc2fa5 100644
--- a/mobile/ethclient.go
+++ b/mobile/ethclient.go
@@ -73,7 +73,8 @@ func (ec *EthereumClient) GetHeaderByNumber(ctx *Context, number int64) (*Header
 
 // GetTransactionByHash returns the transaction with the given hash.
 func (ec *EthereumClient) GetTransactionByHash(ctx *Context, hash *Hash) (*Transaction, error) {
-	tx, err := ec.client.TransactionByHash(ctx.context, hash.hash)
+	// TODO(karalabe): handle isPending
+	tx, _, err := ec.client.TransactionByHash(ctx.context, hash.hash)
 	return &Transaction{tx}, err
 }