1 files changed, 185 insertions, 0 deletions
diff --git a/light/odr_util.go b/light/odr_util.go
new file mode 100644
index 000000000..458f8233b
--- /dev/null
+++ b/light/odr_util.go
@@ -0,0 +1,185 @@
+// 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/>.
+package light
+
+import (
+	"bytes"
+	"errors"
+	"math/big"
+
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/core"
+	"github.com/ethereum/go-ethereum/core/types"
+	"github.com/ethereum/go-ethereum/crypto"
+	"github.com/ethereum/go-ethereum/ethdb"
+	"github.com/ethereum/go-ethereum/logger"
+	"github.com/ethereum/go-ethereum/logger/glog"
+	"github.com/ethereum/go-ethereum/rlp"
+	"golang.org/x/net/context"
+)
+
+var sha3_nil = crypto.Keccak256Hash(nil)
+
+var (
+	ErrNoTrustedCht = errors.New("No trusted canonical hash trie")
+	ErrNoHeader     = errors.New("Header not found")
+
+	ChtFrequency  = uint64(4096)
+	trustedChtKey = []byte("TrustedCHT")
+)
+
+type ChtNode struct {
+	Hash common.Hash
+	Td   *big.Int
+}
+
+type TrustedCht struct {
+	Number uint64
+	Root   common.Hash
+}
+
+func GetTrustedCht(db ethdb.Database) TrustedCht {
+	data, _ := db.Get(trustedChtKey)
+	var res TrustedCht
+	if err := rlp.DecodeBytes(data, &res); err != nil {
+		return TrustedCht{0, common.Hash{}}
+	}
+	return res
+}
+
+func WriteTrustedCht(db ethdb.Database, cht TrustedCht) {
+	data, _ := rlp.EncodeToBytes(cht)
+	db.Put(trustedChtKey, data)
+}
+
+func DeleteTrustedCht(db ethdb.Database) {
+	db.Delete(trustedChtKey)
+}
+
+func GetHeaderByNumber(ctx context.Context, odr OdrBackend, number uint64) (*types.Header, error) {
+	db := odr.Database()
+	hash := core.GetCanonicalHash(db, number)
+	if (hash != common.Hash{}) {
+		// if there is a canonical hash, there is a header too
+		header := core.GetHeader(db, hash, number)
+		if header == nil {
+			panic("Canonical hash present but header not found")
+		}
+		return header, nil
+	}
+
+	cht := GetTrustedCht(db)
+	if number >= cht.Number*ChtFrequency {
+		return nil, ErrNoTrustedCht
+	}
+
+	r := &ChtRequest{ChtRoot: cht.Root, ChtNum: cht.Number, BlockNum: number}
+	if err := odr.Retrieve(ctx, r); err != nil {
+		return nil, err
+	} else {
+		return r.Header, nil
+	}
+}
+
+func GetCanonicalHash(ctx context.Context, odr OdrBackend, number uint64) (common.Hash, error) {
+	hash := core.GetCanonicalHash(odr.Database(), number)
+	if (hash != common.Hash{}) {
+		return hash, nil
+	}
+	header, err := GetHeaderByNumber(ctx, odr, number)
+	if header != nil {
+		return header.Hash(), nil
+	}
+	return common.Hash{}, err
+}
+
+// retrieveContractCode tries to retrieve the contract code of the given account
+// with the given hash from the network (id points to the storage trie belonging
+// to the same account)
+func retrieveContractCode(ctx context.Context, odr OdrBackend, id *TrieID, hash common.Hash) ([]byte, error) {
+	if hash == sha3_nil {
+		return nil, nil
+	}
+	res, _ := odr.Database().Get(hash[:])
+	if res != nil {
+		return res, nil
+	}
+	r := &CodeRequest{Id: id, Hash: hash}
+	if err := odr.Retrieve(ctx, r); err != nil {
+		return nil, err
+	} else {
+		return r.Data, nil
+	}
+}
+
+// GetBodyRLP retrieves the block body (transactions and uncles) in RLP encoding.
+func GetBodyRLP(ctx context.Context, odr OdrBackend, hash common.Hash, number uint64) (rlp.RawValue, error) {
+	if data := core.GetBodyRLP(odr.Database(), hash, number); data != nil {
+		return data, nil
+	}
+	r := &BlockRequest{Hash: hash, Number: number}
+	if err := odr.Retrieve(ctx, r); err != nil {
+		return nil, err
+	} else {
+		return r.Rlp, nil
+	}
+}
+
+// GetBody retrieves the block body (transactons, uncles) corresponding to the
+// hash.
+func GetBody(ctx context.Context, odr OdrBackend, hash common.Hash, number uint64) (*types.Body, error) {
+	data, err := GetBodyRLP(ctx, odr, hash, number)
+	if err != nil {
+		return nil, err
+	}
+	body := new(types.Body)
+	if err := rlp.Decode(bytes.NewReader(data), body); err != nil {
+		glog.V(logger.Error).Infof("invalid block body RLP for hash %x: %v", hash, err)
+		return nil, err
+	}
+	return body, nil
+}
+
+// GetBlock retrieves an entire block corresponding to the hash, assembling it
+// back from the stored header and body.
+func GetBlock(ctx context.Context, odr OdrBackend, hash common.Hash, number uint64) (*types.Block, error) {
+	// Retrieve the block header and body contents
+	header := core.GetHeader(odr.Database(), hash, number)
+	if header == nil {
+		return nil, ErrNoHeader
+	}
+	body, err := GetBody(ctx, odr, hash, number)
+	if err != nil {
+		return nil, err
+	}
+	// Reassemble the block and return
+	return types.NewBlockWithHeader(header).WithBody(body.Transactions, body.Uncles), nil
+}
+
+// GetBlockReceipts retrieves the receipts generated by the transactions included
+// in a block given by its hash.
+func GetBlockReceipts(ctx context.Context, odr OdrBackend, hash common.Hash, number uint64) (types.Receipts, error) {
+	receipts := core.GetBlockReceipts(odr.Database(), hash, number)
+	if receipts != nil {
+		return receipts, nil
+	}
+	r := &ReceiptsRequest{Hash: hash, Number: number}
+	if err := odr.Retrieve(ctx, r); err != nil {
+		return nil, err
+	} else {
+		return r.Receipts, nil
+	}
+}