ipfs-ethdb/database.go
2020-07-12 18:18:25 -05:00

215 lines
7.1 KiB
Go

// VulcanizeDB
// Copyright © 2020 Vulcanize
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
// This program 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 Affero General Public License for more details.
// You should have received a copy of the GNU Affero General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
package ipfsethdb
import (
"context"
"errors"
"fmt"
"strconv"
"strings"
"github.com/ethereum/go-ethereum/ethdb"
"github.com/ipfs/go-blockservice"
)
var (
stateTrieCodec uint64 = 0x96
defaultBatchCapacity = 1024
errNotSupported = errors.New("this operation is not supported")
)
// Database is the type that satisfies the ethdb.Database and ethdb.KeyValueStore interfaces for IPFS Ethereum data
// This is ipfs-backing-datastore agnostic but must operate through a configured ipfs node (and so is subject to lockfile contention with e.g. an ipfs daemon)
// If blockservice block exchange is configured the blockservice can fetch data that are missing locally from IPFS peers
type Database struct {
blockService blockservice.BlockService
}
// NewKeyValueStore returns a ethdb.KeyValueStore interface for IPFS
func NewKeyValueStore(bs blockservice.BlockService) ethdb.KeyValueStore {
return &Database{
blockService: bs,
}
}
// NewDatabase returns a ethdb.Database interface for IPFS
func NewDatabase(bs blockservice.BlockService) ethdb.Database {
return &Database{
blockService: bs,
}
}
// Has satisfies the ethdb.KeyValueReader interface
// Has retrieves if a key is present in the key-value data store
// This only operates on the local blockstore not through the exchange
func (d *Database) Has(key []byte) (bool, error) {
// we are using state codec because we don't know the codec and at this level the codec doesn't matter, the datastore key is multihash-only derived
c, err := Keccak256ToCid(key, stateTrieCodec)
if err != nil {
return false, err
}
return d.blockService.Blockstore().Has(c)
}
// Get satisfies the ethdb.KeyValueReader interface
// Get retrieves the given key if it's present in the key-value data store
func (d *Database) Get(key []byte) ([]byte, error) {
// we are using state codec because we don't know the codec and at this level the codec doesn't matter, the datastore key is multihash-only derived
c, err := Keccak256ToCid(key, stateTrieCodec)
if err != nil {
return nil, err
}
block, err := d.blockService.GetBlock(context.Background(), c)
if err != nil {
return nil, err
}
return block.RawData(), nil
}
// Put satisfies the ethdb.KeyValueWriter interface
// Put inserts the given value into the key-value data store
// Key is expected to be the keccak256 hash of value
func (d *Database) Put(key []byte, value []byte) error {
b, err := NewBlock(key, value)
if err != nil {
return err
}
return d.blockService.AddBlock(b)
}
// Delete satisfies the ethdb.KeyValueWriter interface
// Delete removes the key from the key-value data store
func (d *Database) Delete(key []byte) error {
// we are using state codec because we don't know the codec and at this level the codec doesn't matter, the datastore key is multihash-only derived
c, err := Keccak256ToCid(key, stateTrieCodec)
if err != nil {
return err
}
return d.blockService.DeleteBlock(c)
}
// DatabaseProperty enum type
type DatabaseProperty int
const (
Unknown DatabaseProperty = iota
ExchangeOnline
)
// DatabasePropertyFromString helper function
func DatabasePropertyFromString(property string) (DatabaseProperty, error) {
switch strings.ToLower(property) {
case "exchange", "online":
return ExchangeOnline, nil
default:
return Unknown, fmt.Errorf("unknown database property")
}
}
// Stat satisfies the ethdb.Stater interface
// Stat returns a particular internal stat of the database
func (d *Database) Stat(property string) (string, error) {
prop, err := DatabasePropertyFromString(property)
if err != nil {
return "", err
}
switch prop {
case ExchangeOnline:
online := d.blockService.Exchange().IsOnline()
return strconv.FormatBool(online), nil
default:
return "", fmt.Errorf("unhandled database property")
}
}
// Compact satisfies the ethdb.Compacter interface
// Compact flattens the underlying data store for the given key range
func (d *Database) Compact(start []byte, limit []byte) error {
return errNotSupported
}
// NewBatch satisfies the ethdb.Batcher interface
// NewBatch creates a write-only database that buffers changes to its host db
// until a final write is called
func (d *Database) NewBatch() ethdb.Batch {
b, err := NewBatch(d.blockService, defaultBatchCapacity)
if err != nil {
panic(err)
}
return b
}
// NewIterator satisfies the ethdb.Iteratee interface
// it creates a binary-alphabetical iterator over a subset
// of database content with a particular key prefix, starting at a particular
// initial key (or after, if it does not exist).
//
// Note: This method assumes that the prefix is NOT part of the start, so there's
// no need for the caller to prepend the prefix to the start
func (d *Database) NewIterator(prefix []byte, start []byte) ethdb.Iterator {
return NewIterator(start, prefix, d.blockService)
}
// Close satisfies the io.Closer interface
// Close closes the db connection
func (d *Database) Close() error {
return d.blockService.Close()
}
// HasAncient satisfies the ethdb.AncientReader interface
// HasAncient returns an indicator whether the specified data exists in the ancient store
func (d *Database) HasAncient(kind string, number uint64) (bool, error) {
return false, errNotSupported
}
// Ancient satisfies the ethdb.AncientReader interface
// Ancient retrieves an ancient binary blob from the append-only immutable files
func (d *Database) Ancient(kind string, number uint64) ([]byte, error) {
return nil, errNotSupported
}
// Ancients satisfies the ethdb.AncientReader interface
// Ancients returns the ancient item numbers in the ancient store
func (d *Database) Ancients() (uint64, error) {
return 0, errNotSupported
}
// AncientSize satisfies the ethdb.AncientReader interface
// AncientSize returns the ancient size of the specified category
func (d *Database) AncientSize(kind string) (uint64, error) {
return 0, errNotSupported
}
// AppendAncient satisfies the ethdb.AncientWriter interface
// AppendAncient injects all binary blobs belong to block at the end of the append-only immutable table files
func (d *Database) AppendAncient(number uint64, hash, header, body, receipt, td []byte) error {
return errNotSupported
}
// TruncateAncients satisfies the ethdb.AncientWriter interface
// TruncateAncients discards all but the first n ancient data from the ancient store
func (d *Database) TruncateAncients(n uint64) error {
return errNotSupported
}
// Sync satisfies the ethdb.AncientWriter interface
// Sync flushes all in-memory ancient store data to disk
func (d *Database) Sync() error {
return errNotSupported
}