1 files changed, 257 insertions, 0 deletions
diff --git a/trie/sync_test.go b/trie/sync_test.go
new file mode 100644
index 000000000..9c036a3a9
--- /dev/null
+++ b/trie/sync_test.go
@@ -0,0 +1,257 @@
+// 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/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/ethdb"
+)
+
+// makeTestTrie create a sample test trie to test node-wise reconstruction.
+func makeTestTrie() (ethdb.Database, *Trie, map[string][]byte) {
+	// Create an empty trie
+	db, _ := ethdb.NewMemDatabase()
+	trie, _ := New(common.Hash{}, db)
+
+	// Fill it with some arbitrary data
+	content := make(map[string][]byte)
+	for i := byte(0); i < 255; i++ {
+		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)
+	}
+	trie.Commit()
+
+	// Return the generated trie
+	return db, 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) {
+	trie, err := New(common.BytesToHash(root), db)
+	if err != nil {
+		t.Fatalf("failed to create trie at %x: %v", root, err)
+	}
+	for key, val := range content {
+		if have := trie.Get([]byte(key)); bytes.Compare(have, val) != 0 {
+			t.Errorf("entry %x: content mismatch: have %x, want %x", key, have, val)
+		}
+	}
+}
+
+// Tests that an empty trie is not scheduled for syncing.
+func TestEmptyTrieSync(t *testing.T) {
+	emptyA, _ := New(common.Hash{}, nil)
+	emptyB, _ := New(emptyRoot, nil)
+
+	for i, trie := range []*Trie{emptyA, emptyB} {
+		db, _ := ethdb.NewMemDatabase()
+		if req := NewTrieSync(common.BytesToHash(trie.Root()), db, 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 TestIterativeTrieSyncIndividual(t *testing.T) { testIterativeTrieSync(t, 1) }
+func TestIterativeTrieSyncBatched(t *testing.T)    { testIterativeTrieSync(t, 100) }
+
+func testIterativeTrieSync(t *testing.T, batch int) {
+	// Create a random trie to copy
+	srcDb, srcTrie, srcData := makeTestTrie()
+
+	// Create a destination trie and sync with the scheduler
+	dstDb, _ := ethdb.NewMemDatabase()
+	sched := NewTrieSync(common.BytesToHash(srcTrie.Root()), dstDb, 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.Get(hash.Bytes())
+			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)
+		}
+		queue = append(queue[:0], sched.Missing(batch)...)
+	}
+	// Cross check that the two tries re in sync
+	checkTrieContents(t, dstDb, 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 TestIterativeDelayedTrieSync(t *testing.T) {
+	// Create a random trie to copy
+	srcDb, srcTrie, srcData := makeTestTrie()
+
+	// Create a destination trie and sync with the scheduler
+	dstDb, _ := ethdb.NewMemDatabase()
+	sched := NewTrieSync(common.BytesToHash(srcTrie.Root()), dstDb, 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.Get(hash.Bytes())
+			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)
+		}
+		queue = append(queue[len(results):], sched.Missing(10000)...)
+	}
+	// Cross check that the two tries re in sync
+	checkTrieContents(t, dstDb, 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 TestIterativeRandomTrieSyncIndividual(t *testing.T) { testIterativeRandomTrieSync(t, 1) }
+func TestIterativeRandomTrieSyncBatched(t *testing.T)    { testIterativeRandomTrieSync(t, 100) }
+
+func testIterativeRandomTrieSync(t *testing.T, batch int) {
+	// Create a random trie to copy
+	srcDb, srcTrie, srcData := makeTestTrie()
+
+	// Create a destination trie and sync with the scheduler
+	dstDb, _ := ethdb.NewMemDatabase()
+	sched := NewTrieSync(common.BytesToHash(srcTrie.Root()), dstDb, 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.Get(hash.Bytes())
+			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)
+		}
+		queue = make(map[common.Hash]struct{})
+		for _, hash := range sched.Missing(batch) {
+			queue[hash] = struct{}{}
+		}
+	}
+	// Cross check that the two tries re in sync
+	checkTrieContents(t, dstDb, 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 TestIterativeRandomDelayedTrieSync(t *testing.T) {
+	// Create a random trie to copy
+	srcDb, srcTrie, srcData := makeTestTrie()
+
+	// Create a destination trie and sync with the scheduler
+	dstDb, _ := ethdb.NewMemDatabase()
+	sched := NewTrieSync(common.BytesToHash(srcTrie.Root()), dstDb, 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.Get(hash.Bytes())
+			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)
+		}
+		for _, result := range results {
+			delete(queue, result.Hash)
+		}
+		for _, hash := range sched.Missing(10000) {
+			queue[hash] = struct{}{}
+		}
+	}
+	// Cross check that the two tries re in sync
+	checkTrieContents(t, dstDb, srcTrie.Root(), srcData)
+}
+
+// Tests that a trie sync will not request nodes multiple times, even if they
+// have such references.
+func TestDuplicateAvoidanceTrieSync(t *testing.T) {
+	// Create a random trie to copy
+	srcDb, srcTrie, srcData := makeTestTrie()
+
+	// Create a destination trie and sync with the scheduler
+	dstDb, _ := ethdb.NewMemDatabase()
+	sched := NewTrieSync(common.BytesToHash(srcTrie.Root()), dstDb, 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.Get(hash.Bytes())
+			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)
+		}
+		queue = append(queue[:0], sched.Missing(0)...)
+	}
+	// Cross check that the two tries re in sync
+	checkTrieContents(t, dstDb, srcTrie.Root(), srcData)
+}