path: root/trie/sync_test.go

// 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 trie

import (
    "bytes"
    "testing"

    "github.com/dexon-foundation/dexon/common"
    "github.com/dexon-foundation/dexon/ethdb"
)

// makeTestTrie create a sample test trie to test node-wise reconstruction.
func makeTestTrie() (*Database, *Trie, map[string][]byte) {
    // Create an empty trie
    triedb := NewDatabase(ethdb.NewMemDatabase())
    trie, _ := New(common.Hash{}, triedb)

    // Fill it with some arbitrary data
    content := make(map[string][]byte)
    for i := byte(0); i < 255; i++ {
        // Map the same data under multiple keys
        key, val := common.LeftPadBytes([]byte{1, i}, 32), []byte{i}
        content[string(key)] = val
        trie.Update(key, val)

        key, val = common.LeftPadBytes([]byte{2, i}, 32), []byte{i}
        content[string(key)] = val
        trie.Update(key, val)

        // Add some other data to inflate the trie
        for j := byte(3); j < 13; j++ {
            key, val = common.LeftPadBytes([]byte{j, i}, 32), []byte{j, i}
            content[string(key)] = val
            trie.Update(key, val)
        }
    }
    trie.Commit(nil)

    // Return the generated trie
    return triedb, trie, content
}

// checkTrieContents cross references a reconstructed trie with an expected data
// content map.
func checkTrieContents(t *testing.T, db *Database, root []byte, content map[string][]byte) {
    // Check root availability and trie contents
    trie, err := New(common.BytesToHash(root), db)
    if err != nil {
        t.Fatalf("failed to create trie at %x: %v", root, err)
    }
    if err := checkTrieConsistency(db, common.BytesToHash(root)); err != nil {
        t.Fatalf("inconsistent trie at %x: %v", root, err)
    }
    for key, val := range content {
        if have := trie.Get([]byte(key)); !bytes.Equal(have, val) {
            t.Errorf("entry %x: content mismatch: have %x, want %x", key, have, val)
        }
    }
}

// checkTrieConsistency checks that all nodes in a trie are indeed present.
func checkTrieConsistency(db *Database, root common.Hash) error {
    // Create and iterate a trie rooted in a subnode
    trie, err := New(root, db)
    if err != nil {
        return nil // Consider a non existent state consistent
    }
    it := trie.NodeIterator(nil)
    for it.Next(true) {
    }
    return it.Error()
}

// Tests that an empty trie is not scheduled for syncing.
func TestEmptySync(t *testing.T) {
    dbA := NewDatabase(ethdb.NewMemDatabase())
    dbB := NewDatabase(ethdb.NewMemDatabase())
    emptyA, _ := New(common.Hash{}, dbA)
    emptyB, _ := New(emptyRoot, dbB)

    for i, trie := range []*Trie{emptyA, emptyB} {
        if req := NewSync(trie.Hash(), ethdb.NewMemDatabase(), nil).Missing(1); len(req) != 0 {
            t.Errorf("test %d: content requested for empty trie: %v", i, req)
        }
    }
}

// Tests that given a root hash, a trie can sync iteratively on a single thread,
// requesting retrieval tasks and returning all of them in one go.
func TestIterativeSyncIndividual(t *testing.T) { testIterativeSync(t, 1) }
func TestIterativeSyncBatched(t *testing.T)    { testIterativeSync(t, 100) }

func testIterativeSync(t *testing.T, batch int) {
    // Create a random trie to copy
    srcDb, srcTrie, srcData := makeTestTrie()

    // Create a destination trie and sync with the scheduler
    diskdb := ethdb.NewMemDatabase()
    triedb := NewDatabase(diskdb)
    sched := NewSync(srcTrie.Hash(), diskdb, nil)

    queue := append([]common.Hash{}, sched.Missing(batch)...)
    for len(queue) > 0 {
        results := make([]SyncResult, len(queue))
        for i, hash := range queue {
            data, err := srcDb.Node(hash)
            if err != nil {
                t.Fatalf("failed to retrieve node data for %x: %v", hash, err)
            }
            results[i] = SyncResult{hash, data}
        }
        if _, index, err := sched.Process(results); err != nil {
            t.Fatalf("failed to process result #%d: %v", index, err)
        }
        if index, err := sched.Commit(diskdb); err != nil {
            t.Fatalf("failed to commit data #%d: %v", index, err)
        }
        queue = append(queue[:0], sched.Missing(batch)...)
    }
    // Cross check that the two tries are in sync
    checkTrieContents(t, triedb, srcTrie.Root(), srcData)
}

// Tests that the trie scheduler can correctly reconstruct the state even if only
// partial results are returned, and the others sent only later.
func TestIterativeDelayedSync(t *testing.T) {
    // Create a random trie to copy
    srcDb, srcTrie, srcData := makeTestTrie()

    // Create a destination trie and sync with the scheduler
    diskdb := ethdb.NewMemDatabase()
    triedb := NewDatabase(diskdb)
    sched := NewSync(srcTrie.Hash(), diskdb, nil)

    queue := append([]common.Hash{}, sched.Missing(10000)...)
    for len(queue) > 0 {
        // Sync only half of the scheduled nodes
        results := make([]SyncResult, len(queue)/2+1)
        for i, hash := range queue[:len(results)] {
            data, err := srcDb.Node(hash)
            if err != nil {
                t.Fatalf("failed to retrieve node data for %x: %v", hash, err)
            }
            results[i] = SyncResult{hash, data}
        }
        if _, index, err := sched.Process(results); err != nil {
            t.Fatalf("failed to process result #%d: %v", index, err)
        }
        if index, err := sched.Commit(diskdb); err != nil {
            t.Fatalf("failed to commit data #%d: %v", index, err)
        }
        queue = append(queue[len(results):], sched.Missing(10000)...)
    }
    // Cross check that the two tries are in sync
    checkTrieContents(t, triedb, srcTrie.Root(), srcData)
}

// Tests that given a root hash, a trie can sync iteratively on a single thread,
// requesting retrieval tasks and returning all of them in one go, however in a
// random order.
func TestIterativeRandomSyncIndividual(t *testing.T) { testIterativeRandomSync(t, 1) }
func TestIterativeRandomSyncBatched(t *testing.T)    { testIterativeRandomSync(t, 100) }

func testIterativeRandomSync(t *testing.T, batch int) {
    // Create a random trie to copy
    srcDb, srcTrie, srcData := makeTestTrie()

    // Create a destination trie and sync with the scheduler
    diskdb := ethdb.NewMemDatabase()
    triedb := NewDatabase(diskdb)
    sched := NewSync(srcTrie.Hash(), diskdb, nil)

    queue := make(map[common.Hash]struct{})
    for _, hash := range sched.Missing(batch) {
        queue[hash] = struct{}{}
    }
    for len(queue) > 0 {
        // Fetch all the queued nodes in a random order
        results := make([]SyncResult, 0, len(queue))
        for hash := range queue {
            data, err := srcDb.Node(hash)
            if err != nil {
                t.Fatalf("failed to retrieve node data for %x: %v", hash, err)
            }
            results = append(results, SyncResult{hash, data})
        }
        // Feed the retrieved results back and queue new tasks
        if _, index, err := sched.Process(results); err != nil {
            t.Fatalf("failed to process result #%d: %v", index, err)
        }
        if index, err := sched.Commit(diskdb); err != nil {
            t.Fatalf("failed to commit data #%d: %v", index, err)
        }
        queue = make(map[common.Hash]struct{})
        for _, hash := range sched.Missing(batch) {
            queue[hash] = struct{}{}
        }
    }
    // Cross check that the two tries are in sync
    checkTrieContents(t, triedb, srcTrie.Root(), srcData)
}

// Tests that the trie scheduler can correctly reconstruct the state even if only
// partial results are returned (Even those randomly), others sent only later.
func TestIterativeRandomDelayedSync(t *testing.T) {
    // Create a random trie to copy
    srcDb, srcTrie, srcData := makeTestTrie()

    // Create a destination trie and sync with the scheduler
    diskdb := ethdb.NewMemDatabase()
    triedb := NewDatabase(diskdb)
    sched := NewSync(srcTrie.Hash(), diskdb, nil)

    queue := make(map[common.Hash]struct{})
    for _, hash := range sched.Missing(10000) {
        queue[hash] = struct{}{}
    }
    for len(queue) > 0 {
        // Sync only half of the scheduled nodes, even those in random order
        results := make([]SyncResult, 0, len(queue)/2+1)
        for hash := range queue {
            data, err := srcDb.Node(hash)
            if err != nil {
                t.Fatalf("failed to retrieve node data for %x: %v", hash, err)
            }
            results = append(results, SyncResult{hash, data})

            if len(results) >= cap(results) {
                break
            }
        }
        // Feed the retrieved results back and queue new tasks
        if _, index, err := sched.Process(results); err != nil {
            t.Fatalf("failed to process result #%d: %v", index, err)
        }
        if index, err := sched.Commit(diskdb); err != nil {
            t.Fatalf("failed to commit data #%d: %v", index, err)
        }
        for _, result := range results {
            delete(queue, result.Hash)
        }
        for _, hash := range sched.Missing(10000) {
            queue[hash] = struct{}{}
        }
    }
    // Cross check that the two tries are in sync
    checkTrieContents(t, triedb, srcTrie.Root(), srcData)
}

// Tests that a trie sync will not request nodes multiple times, even if they
// have such references.
func TestDuplicateAvoidanceSync(t *testing.T) {
    // Create a random trie to copy
    srcDb, srcTrie, srcData := makeTestTrie()

    // Create a destination trie and sync with the scheduler
    diskdb := ethdb.NewMemDatabase()
    triedb := NewDatabase(diskdb)
    sched := NewSync(srcTrie.Hash(), diskdb, nil)

    queue := append([]common.Hash{}, sched.Missing(0)...)
    requested := make(map[common.Hash]struct{})

    for len(queue) > 0 {
        results := make([]SyncResult, len(queue))
        for i, hash := range queue {
            data, err := srcDb.Node(hash)
            if err != nil {
                t.Fatalf("failed to retrieve node data for %x: %v", hash, err)
            }
            if _, ok := requested[hash]; ok {
                t.Errorf("hash %x already requested once", hash)
            }
            requested[hash] = struct{}{}

            results[i] = SyncResult{hash, data}
        }
        if _, index, err := sched.Process(results); err != nil {
            t.Fatalf("failed to process result #%d: %v", index, err)
        }
        if index, err := sched.Commit(diskdb); err != nil {
            t.Fatalf("failed to commit data #%d: %v", index, err)
        }
        queue = append(queue[:0], sched.Missing(0)...)
    }
    // Cross check that the two tries are in sync
    checkTrieContents(t, triedb, srcTrie.Root(), srcData)
}

// Tests that at any point in time during a sync, only complete sub-tries are in
// the database.
func TestIncompleteSync(t *testing.T) {
    // Create a random trie to copy
    srcDb, srcTrie, _ := makeTestTrie()

    // Create a destination trie and sync with the scheduler
    diskdb := ethdb.NewMemDatabase()
    triedb := NewDatabase(diskdb)
    sched := NewSync(srcTrie.Hash(), diskdb, nil)

    added := []common.Hash{}
    queue := append([]common.Hash{}, sched.Missing(1)...)
    for len(queue) > 0 {
        // Fetch a batch of trie nodes
        results := make([]SyncResult, len(queue))
        for i, hash := range queue {
            data, err := srcDb.Node(hash)
            if err != nil {
                t.Fatalf("failed to retrieve node data for %x: %v", hash, err)
            }
            results[i] = SyncResult{hash, data}
        }
        // Process each of the trie nodes
        if _, index, err := sched.Process(results); err != nil {
            t.Fatalf("failed to process result #%d: %v", index, err)
        }
        if index, err := sched.Commit(diskdb); err != nil {
            t.Fatalf("failed to commit data #%d: %v", index, err)
        }
        for _, result := range results {
            added = append(added, result.Hash)
        }
        // Check that all known sub-tries in the synced trie are complete
        for _, root := range added {
            if err := checkTrieConsistency(triedb, root); err != nil {
                t.Fatalf("trie inconsistent: %v", err)
            }
        }
        // Fetch the next batch to retrieve
        queue = append(queue[:0], sched.Missing(1)...)
    }
    // Sanity check that removing any node from the database is detected
    for _, node := range added[1:] {
        key := node.Bytes()
        value, _ := diskdb.Get(key)

        diskdb.Delete(key)
        if err := checkTrieConsistency(triedb, added[0]); err == nil {
            t.Fatalf("trie inconsistency not caught, missing: %x", key)
        }
        diskdb.Put(key, value)
    }
}