path: root/light/nodeset.go

// Copyright 2017 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 (
    "errors"
    "sync"

    "github.com/ethereum/go-ethereum/common"
    "github.com/ethereum/go-ethereum/crypto"
    "github.com/ethereum/go-ethereum/ethdb"
    "github.com/ethereum/go-ethereum/rlp"
)

// NodeSet stores a set of trie nodes. It implements trie.Database and can also
// act as a cache for another trie.Database.
type NodeSet struct {
    nodes map[string][]byte
    order []string

    dataSize int
    lock     sync.RWMutex
}

// NewNodeSet creates an empty node set
func NewNodeSet() *NodeSet {
    return &NodeSet{
        nodes: make(map[string][]byte),
    }
}

// Put stores a new node in the set
func (db *NodeSet) Put(key []byte, value []byte) error {
    db.lock.Lock()
    defer db.lock.Unlock()

    if _, ok := db.nodes[string(key)]; ok {
        return nil
    }
    keystr := string(key)

    db.nodes[keystr] = common.CopyBytes(value)
    db.order = append(db.order, keystr)
    db.dataSize += len(value)

    return nil
}

// Delete removes a node from the set
func (db *NodeSet) Delete(key []byte) error {
    db.lock.Lock()
    defer db.lock.Unlock()

    delete(db.nodes, string(key))
    return nil
}

// Get returns a stored node
func (db *NodeSet) Get(key []byte) ([]byte, error) {
    db.lock.RLock()
    defer db.lock.RUnlock()

    if entry, ok := db.nodes[string(key)]; ok {
        return entry, nil
    }
    return nil, errors.New("not found")
}

// Has returns true if the node set contains the given key
func (db *NodeSet) Has(key []byte) (bool, error) {
    _, err := db.Get(key)
    return err == nil, nil
}

// KeyCount returns the number of nodes in the set
func (db *NodeSet) KeyCount() int {
    db.lock.RLock()
    defer db.lock.RUnlock()

    return len(db.nodes)
}

// DataSize returns the aggregated data size of nodes in the set
func (db *NodeSet) DataSize() int {
    db.lock.RLock()
    defer db.lock.RUnlock()

    return db.dataSize
}

// NodeList converts the node set to a NodeList
func (db *NodeSet) NodeList() NodeList {
    db.lock.RLock()
    defer db.lock.RUnlock()

    var values NodeList
    for _, key := range db.order {
        values = append(values, db.nodes[key])
    }
    return values
}

// Store writes the contents of the set to the given database
func (db *NodeSet) Store(target ethdb.KeyValueWriter) {
    db.lock.RLock()
    defer db.lock.RUnlock()

    for key, value := range db.nodes {
        target.Put([]byte(key), value)
    }
}

// NodeList stores an ordered list of trie nodes. It implements ethdb.KeyValueWriter.
type NodeList []rlp.RawValue

// Store writes the contents of the list to the given database
func (n NodeList) Store(db ethdb.KeyValueWriter) {
    for _, node := range n {
        db.Put(crypto.Keccak256(node), node)
    }
}

// NodeSet converts the node list to a NodeSet
func (n NodeList) NodeSet() *NodeSet {
    db := NewNodeSet()
    n.Store(db)
    return db
}

// Put stores a new node at the end of the list
func (n *NodeList) Put(key []byte, value []byte) error {
    *n = append(*n, value)
    return nil
}

// Delete panics as there's no reason to remove a node from the list.
func (n *NodeList) Delete(key []byte) error {
    panic("not supported")
}

// DataSize returns the aggregated data size of nodes in the list
func (n NodeList) DataSize() int {
    var size int
    for _, node := range n {
        size += len(node)
    }
    return size
}