Golang Db.Sync方法代碼示例

// chainSetup is used to create a new db and chain instance with the genesis
// block already inserted.  In addition to the new chain instnce, it returns
// a teardown function the caller should invoke when done testing to clean up.
func chainSetup(dbName string) (*blockchain.BlockChain, func(), error) {
	if !isSupportedDbType(testDbType) {
		return nil, nil, fmt.Errorf("unsupported db type %v", testDbType)
	}

	// Handle memory database specially since it doesn't need the disk
	// specific handling.
	var db database.Db
	var teardown func()
	if testDbType == "memdb" {
		ndb, err := database.CreateDB(testDbType)
		if err != nil {
			return nil, nil, fmt.Errorf("error creating db: %v", err)
		}
		db = ndb

		// Setup a teardown function for cleaning up.  This function is
		// returned to the caller to be invoked when it is done testing.
		teardown = func() {
			db.Close()
		}
	} else {
		// Create the root directory for test databases.
		if !fileExists(testDbRoot) {
			if err := os.MkdirAll(testDbRoot, 0700); err != nil {
				err := fmt.Errorf("unable to create test db "+
					"root: %v", err)
				return nil, nil, err
			}
		}

		// Create a new database to store the accepted blocks into.
		dbPath := filepath.Join(testDbRoot, dbName)
		_ = os.RemoveAll(dbPath)
		ndb, err := database.CreateDB(testDbType, dbPath)
		if err != nil {
			return nil, nil, fmt.Errorf("error creating db: %v", err)
		}
		db = ndb

		// Setup a teardown function for cleaning up.  This function is
		// returned to the caller to be invoked when it is done testing.
		teardown = func() {
			dbVersionPath := filepath.Join(testDbRoot, dbName+".ver")
			db.Sync()
			db.Close()
			os.RemoveAll(dbPath)
			os.Remove(dbVersionPath)
			os.RemoveAll(testDbRoot)
		}
	}

	// Insert the main network genesis block.  This is part of the initial
	// database setup.
	genesisBlock := btcutil.NewBlock(chaincfg.MainNetParams.GenesisBlock)
	_, err := db.InsertBlock(genesisBlock)
	if err != nil {
		teardown()
		err := fmt.Errorf("failed to insert genesis block: %v", err)
		return nil, nil, err
	}

	chain := blockchain.New(db, &chaincfg.MainNetParams, nil, nil)
	return chain, teardown, nil
}

// testAddrIndexOperations ensures that all normal operations concerning
// the optional address index function correctly.
func testAddrIndexOperations(t *testing.T, db database.Db, newestBlock *btcutil.Block, newestSha *wire.ShaHash, newestBlockIdx int32) {
	// Metadata about the current addr index state should be unset.
	sha, height, err := db.FetchAddrIndexTip()
	if err != database.ErrAddrIndexDoesNotExist {
		t.Fatalf("Address index metadata shouldn't be in db, hasn't been built up yet.")
	}

	var zeroHash wire.ShaHash
	if !sha.IsEqual(&zeroHash) {
		t.Fatalf("AddrIndexTip wrong hash got: %s, want %s", sha, &zeroHash)

	}

	if height != -1 {
		t.Fatalf("Addrindex not built up, yet a block index tip has been set to: %d.", height)
	}

	// Test enforcement of constraints for "limit" and "skip"
	var fakeAddr btcutil.Address
	_, _, err = db.FetchTxsForAddr(fakeAddr, -1, 0, false)
	if err == nil {
		t.Fatalf("Negative value for skip passed, should return an error")
	}

	_, _, err = db.FetchTxsForAddr(fakeAddr, 0, -1, false)
	if err == nil {
		t.Fatalf("Negative value for limit passed, should return an error")
	}

	// Simple test to index outputs(s) of the first tx.
	testIndex := make(database.BlockAddrIndex)
	testTx, err := newestBlock.Tx(0)
	if err != nil {
		t.Fatalf("Block has no transactions, unable to test addr "+
			"indexing, err %v", err)
	}

	// Extract the dest addr from the tx.
	_, testAddrs, _, err := txscript.ExtractPkScriptAddrs(testTx.MsgTx().TxOut[0].PkScript, &chaincfg.MainNetParams)
	if err != nil {
		t.Fatalf("Unable to decode tx output, err %v", err)
	}

	// Extract the hash160 from the output script.
	var hash160Bytes [ripemd160.Size]byte
	testHash160 := testAddrs[0].(*btcutil.AddressPubKey).AddressPubKeyHash().ScriptAddress()
	copy(hash160Bytes[:], testHash160[:])

	// Create a fake index.
	blktxLoc, _ := newestBlock.TxLoc()
	testIndex[hash160Bytes] = []*wire.TxLoc{&blktxLoc[0]}

	// Insert our test addr index into the DB.
	err = db.UpdateAddrIndexForBlock(newestSha, newestBlockIdx, testIndex)
	if err != nil {
		t.Fatalf("UpdateAddrIndexForBlock: failed to index"+
			" addrs for block #%d (%s) "+
			"err %v", newestBlockIdx, newestSha, err)
	}

	// Chain Tip of address should've been updated.
	assertAddrIndexTipIsUpdated(db, t, newestSha, newestBlockIdx)

	// Check index retrieval.
	txReplies, _, err := db.FetchTxsForAddr(testAddrs[0], 0, 1000, false)
	if err != nil {
		t.Fatalf("FetchTxsForAddr failed to correctly fetch txs for an "+
			"address, err %v", err)
	}
	// Should have one reply.
	if len(txReplies) != 1 {
		t.Fatalf("Failed to properly index tx by address.")
	}

	// Our test tx and indexed tx should have the same sha.
	indexedTx := txReplies[0]
	if !bytes.Equal(indexedTx.Sha.Bytes(), testTx.Sha().Bytes()) {
		t.Fatalf("Failed to fetch proper indexed tx. Expected sha %v, "+
			"fetched %v", testTx.Sha(), indexedTx.Sha)
	}

	// Shut down DB.
	db.Sync()
	db.Close()

	// Re-Open, tip still should be updated to current height and sha.
	db, err = database.OpenDB("leveldb", "tstdbopmode")
	if err != nil {
		t.Fatalf("Unable to re-open created db, err %v", err)
	}
	assertAddrIndexTipIsUpdated(db, t, newestSha, newestBlockIdx)

	// Delete the entire index.
	err = db.DeleteAddrIndex()
	if err != nil {
		t.Fatalf("Couldn't delete address index, err %v", err)
	}

//.........這裏部分代碼省略.........