path: root/swarm/storage/mock/mem/mem.go

// Copyright 2018 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 mem implements a mock store that keeps all chunk data in memory.
// While it can be used for testing on smaller scales, the main purpose of this
// package is to provide the simplest reference implementation of a mock store.
package mem

import (
    "archive/tar"
    "bytes"
    "encoding/json"
    "io"
    "io/ioutil"
    "sort"
    "sync"

    "github.com/ethereum/go-ethereum/common"
    "github.com/ethereum/go-ethereum/swarm/storage/mock"
)

// GlobalStore stores all chunk data and also keys and node addresses relations.
// It implements mock.GlobalStore interface.
type GlobalStore struct {
    // holds a slice of keys per node
    nodeKeys map[common.Address][][]byte
    // holds which key is stored on which nodes
    keyNodes map[string][]common.Address
    // all node addresses
    nodes []common.Address
    // all keys
    keys [][]byte
    // all keys data
    data map[string][]byte
    mu   sync.RWMutex
}

// NewGlobalStore creates a new instance of GlobalStore.
func NewGlobalStore() *GlobalStore {
    return &GlobalStore{
        nodeKeys: make(map[common.Address][][]byte),
        keyNodes: make(map[string][]common.Address),
        nodes:    make([]common.Address, 0),
        keys:     make([][]byte, 0),
        data:     make(map[string][]byte),
    }
}

// NewNodeStore returns a new instance of NodeStore that retrieves and stores
// chunk data only for a node with address addr.
func (s *GlobalStore) NewNodeStore(addr common.Address) *mock.NodeStore {
    return mock.NewNodeStore(addr, s)
}

// Get returns chunk data if the chunk with key exists for node
// on address addr.
func (s *GlobalStore) Get(addr common.Address, key []byte) (data []byte, err error) {
    s.mu.RLock()
    defer s.mu.RUnlock()

    if _, has := s.nodeKeyIndex(addr, key); !has {
        return nil, mock.ErrNotFound
    }

    data, ok := s.data[string(key)]
    if !ok {
        return nil, mock.ErrNotFound
    }
    return data, nil
}

// Put saves the chunk data for node with address addr.
func (s *GlobalStore) Put(addr common.Address, key []byte, data []byte) error {
    s.mu.Lock()
    defer s.mu.Unlock()

    if i, found := s.nodeKeyIndex(addr, key); !found {
        s.nodeKeys[addr] = append(s.nodeKeys[addr], nil)
        copy(s.nodeKeys[addr][i+1:], s.nodeKeys[addr][i:])
        s.nodeKeys[addr][i] = key
    }

    if i, found := s.keyNodeIndex(key, addr); !found {
        k := string(key)
        s.keyNodes[k] = append(s.keyNodes[k], addr)
        copy(s.keyNodes[k][i+1:], s.keyNodes[k][i:])
        s.keyNodes[k][i] = addr
    }

    if i, found := s.nodeIndex(addr); !found {
        s.nodes = append(s.nodes, addr)
        copy(s.nodes[i+1:], s.nodes[i:])
        s.nodes[i] = addr
    }

    if i, found := s.keyIndex(key); !found {
        s.keys = append(s.keys, nil)
        copy(s.keys[i+1:], s.keys[i:])
        s.keys[i] = key
    }

    s.data[string(key)] = data

    return nil
}

// Delete removes the chunk data for node with address addr.
func (s *GlobalStore) Delete(addr common.Address, key []byte) error {
    s.mu.Lock()
    defer s.mu.Unlock()

    if i, has := s.nodeKeyIndex(addr, key); has {
        s.nodeKeys[addr] = append(s.nodeKeys[addr][:i], s.nodeKeys[addr][i+1:]...)
    }

    k := string(key)
    if i, on := s.keyNodeIndex(key, addr); on {
        s.keyNodes[k] = append(s.keyNodes[k][:i], s.keyNodes[k][i+1:]...)
    }

    if len(s.nodeKeys[addr]) == 0 {
        if i, found := s.nodeIndex(addr); found {
            s.nodes = append(s.nodes[:i], s.nodes[i+1:]...)
        }
    }

    if len(s.keyNodes[k]) == 0 {
        if i, found := s.keyIndex(key); found {
            s.keys = append(s.keys[:i], s.keys[i+1:]...)
        }
    }
    return nil
}

// HasKey returns whether a node with addr contains the key.
func (s *GlobalStore) HasKey(addr common.Address, key []byte) (yes bool) {
    s.mu.RLock()
    defer s.mu.RUnlock()

    _, yes = s.nodeKeyIndex(addr, key)
    return yes
}

// keyIndex returns the index of a key in keys slice.
func (s *GlobalStore) keyIndex(key []byte) (index int, found bool) {
    l := len(s.keys)
    index = sort.Search(l, func(i int) bool {
        return bytes.Compare(s.keys[i], key) >= 0
    })
    found = index < l && bytes.Equal(s.keys[index], key)
    return index, found
}

// nodeIndex returns the index of a node address in nodes slice.
func (s *GlobalStore) nodeIndex(addr common.Address) (index int, found bool) {
    l := len(s.nodes)
    index = sort.Search(l, func(i int) bool {
        return bytes.Compare(s.nodes[i][:], addr[:]) >= 0
    })
    found = index < l && bytes.Equal(s.nodes[index][:], addr[:])
    return index, found
}

// nodeKeyIndex returns the index of a key in nodeKeys slice.
func (s *GlobalStore) nodeKeyIndex(addr common.Address, key []byte) (index int, found bool) {
    l := len(s.nodeKeys[addr])
    index = sort.Search(l, func(i int) bool {
        return bytes.Compare(s.nodeKeys[addr][i], key) >= 0
    })
    found = index < l && bytes.Equal(s.nodeKeys[addr][index], key)
    return index, found
}

// keyNodeIndex returns the index of a node address in keyNodes slice.
func (s *GlobalStore) keyNodeIndex(key []byte, addr common.Address) (index int, found bool) {
    k := string(key)
    l := len(s.keyNodes[k])
    index = sort.Search(l, func(i int) bool {
        return bytes.Compare(s.keyNodes[k][i][:], addr[:]) >= 0
    })
    found = index < l && s.keyNodes[k][index] == addr
    return index, found
}

// Keys returns a paginated list of keys on all nodes.
func (s *GlobalStore) Keys(startKey []byte, limit int) (keys mock.Keys, err error) {
    s.mu.RLock()
    defer s.mu.RUnlock()

    var i int
    if startKey != nil {
        i, _ = s.keyIndex(startKey)
    }
    total := len(s.keys)
    max := maxIndex(i, limit, total)
    keys.Keys = make([][]byte, 0, max-i)
    for ; i < max; i++ {
        keys.Keys = append(keys.Keys, append([]byte(nil), s.keys[i]...))
    }
    if total > max {
        keys.Next = s.keys[max]
    }
    return keys, nil
}

// Nodes returns a paginated list of all known nodes.
func (s *GlobalStore) Nodes(startAddr *common.Address, limit int) (nodes mock.Nodes, err error) {
    s.mu.RLock()
    defer s.mu.RUnlock()

    var i int
    if startAddr != nil {
        i, _ = s.nodeIndex(*startAddr)
    }
    total := len(s.nodes)
    max := maxIndex(i, limit, total)
    nodes.Addrs = make([]common.Address, 0, max-i)
    for ; i < max; i++ {
        nodes.Addrs = append(nodes.Addrs, s.nodes[i])
    }
    if total > max {
        nodes.Next = &s.nodes[max]
    }
    return nodes, nil
}

// NodeKeys returns a paginated list of keys on a node with provided address.
func (s *GlobalStore) NodeKeys(addr common.Address, startKey []byte, limit int) (keys mock.Keys, err error) {
    s.mu.RLock()
    defer s.mu.RUnlock()

    var i int
    if startKey != nil {
        i, _ = s.nodeKeyIndex(addr, startKey)
    }
    total := len(s.nodeKeys[addr])
    max := maxIndex(i, limit, total)
    keys.Keys = make([][]byte, 0, max-i)
    for ; i < max; i++ {
        keys.Keys = append(keys.Keys, append([]byte(nil), s.nodeKeys[addr][i]...))
    }
    if total > max {
        keys.Next = s.nodeKeys[addr][max]
    }
    return keys, nil
}

// KeyNodes returns a paginated list of nodes that contain a particular key.
func (s *GlobalStore) KeyNodes(key []byte, startAddr *common.Address, limit int) (nodes mock.Nodes, err error) {
    s.mu.RLock()
    defer s.mu.RUnlock()

    var i int
    if startAddr != nil {
        i, _ = s.keyNodeIndex(key, *startAddr)
    }
    total := len(s.keyNodes[string(key)])
    max := maxIndex(i, limit, total)
    nodes.Addrs = make([]common.Address, 0, max-i)
    for ; i < max; i++ {
        nodes.Addrs = append(nodes.Addrs, s.keyNodes[string(key)][i])
    }
    if total > max {
        nodes.Next = &s.keyNodes[string(key)][max]
    }
    return nodes, nil
}

// maxIndex returns the end index for one page listing
// based on the start index, limit and total number of elements.
func maxIndex(start, limit, total int) (max int) {
    if limit <= 0 {
        limit = mock.DefaultLimit
    }
    if limit > mock.MaxLimit {
        limit = mock.MaxLimit
    }
    max = total
    if start+limit < max {
        max = start + limit
    }
    return max
}

// Import reads tar archive from a reader that contains exported chunk data.
// It returns the number of chunks imported and an error.
func (s *GlobalStore) Import(r io.Reader) (n int, err error) {
    s.mu.Lock()
    defer s.mu.Unlock()

    tr := tar.NewReader(r)

    for {
        hdr, err := tr.Next()
        if err != nil {
            if err == io.EOF {
                break
            }
            return n, err
        }

        data, err := ioutil.ReadAll(tr)
        if err != nil {
            return n, err
        }

        var c mock.ExportedChunk
        if err = json.Unmarshal(data, &c); err != nil {
            return n, err
        }

        key := common.Hex2Bytes(hdr.Name)
        s.keyNodes[string(key)] = c.Addrs
        for _, addr := range c.Addrs {
            if i, has := s.nodeKeyIndex(addr, key); !has {
                s.nodeKeys[addr] = append(s.nodeKeys[addr], nil)
                copy(s.nodeKeys[addr][i+1:], s.nodeKeys[addr][i:])
                s.nodeKeys[addr][i] = key
            }
            if i, found := s.nodeIndex(addr); !found {
                s.nodes = append(s.nodes, addr)
                copy(s.nodes[i+1:], s.nodes[i:])
                s.nodes[i] = addr
            }
        }
        if i, found := s.keyIndex(key); !found {
            s.keys = append(s.keys, nil)
            copy(s.keys[i+1:], s.keys[i:])
            s.keys[i] = key
        }
        s.data[string(key)] = c.Data
        n++
    }
    return n, err
}

// Export writes to a writer a tar archive with all chunk data from
// the store. It returns the number of chunks exported and an error.
func (s *GlobalStore) Export(w io.Writer) (n int, err error) {
    s.mu.RLock()
    defer s.mu.RUnlock()

    tw := tar.NewWriter(w)
    defer tw.Close()

    buf := bytes.NewBuffer(make([]byte, 0, 1024))
    encoder := json.NewEncoder(buf)
    for key, addrs := range s.keyNodes {
        buf.Reset()
        if err = encoder.Encode(mock.ExportedChunk{
            Addrs: addrs,
            Data:  s.data[key],
        }); err != nil {
            return n, err
        }

        data := buf.Bytes()
        hdr := &tar.Header{
            Name: common.Bytes2Hex([]byte(key)),
            Mode: 0644,
            Size: int64(len(data)),
        }
        if err := tw.WriteHeader(hdr); err != nil {
            return n, err
        }
        if _, err := tw.Write(data); err != nil {
            return n, err
        }
        n++
    }
    return n, err
}