+++ /dev/null
-// Copyright (c) 2015-2016 The btcsuite developers
-// Use of this source code is governed by an ISC
-// license that can be found in the LICENSE file.
-
-package database_test
-
-import (
- "bytes"
- "fmt"
- "os"
- "path/filepath"
-
- "github.com/btcsuite/btcd/chaincfg"
- "github.com/btcsuite/btcd/database"
- _ "github.com/btcsuite/btcd/database/ffldb"
- "github.com/btcsuite/btcd/wire"
- "github.com/btcsuite/btcutil"
-)
-
-// This example demonstrates creating a new database.
-func ExampleCreate() {
- // This example assumes the ffldb driver is imported.
- //
- // import (
- // "github.com/btcsuite/btcd/database"
- // _ "github.com/btcsuite/btcd/database/ffldb"
- // )
-
- // Create a database and schedule it to be closed and removed on exit.
- // Typically you wouldn't want to remove the database right away like
- // this, nor put it in the temp directory, but it's done here to ensure
- // the example cleans up after itself.
- dbPath := filepath.Join(os.TempDir(), "examplecreate")
- db, err := database.Create("ffldb", dbPath, wire.MainNet)
- if err != nil {
- fmt.Println(err)
- return
- }
- defer os.RemoveAll(dbPath)
- defer db.Close()
-
- // Output:
-}
-
-// This example demonstrates creating a new database and using a managed
-// read-write transaction to store and retrieve metadata.
-func Example_basicUsage() {
- // This example assumes the ffldb driver is imported.
- //
- // import (
- // "github.com/btcsuite/btcd/database"
- // _ "github.com/btcsuite/btcd/database/ffldb"
- // )
-
- // Create a database and schedule it to be closed and removed on exit.
- // Typically you wouldn't want to remove the database right away like
- // this, nor put it in the temp directory, but it's done here to ensure
- // the example cleans up after itself.
- dbPath := filepath.Join(os.TempDir(), "exampleusage")
- db, err := database.Create("ffldb", dbPath, wire.MainNet)
- if err != nil {
- fmt.Println(err)
- return
- }
- defer os.RemoveAll(dbPath)
- defer db.Close()
-
- // Use the Update function of the database to perform a managed
- // read-write transaction. The transaction will automatically be rolled
- // back if the supplied inner function returns a non-nil error.
- err = db.Update(func(tx database.Tx) error {
- // Store a key/value pair directly in the metadata bucket.
- // Typically a nested bucket would be used for a given feature,
- // but this example is using the metadata bucket directly for
- // simplicity.
- key := []byte("mykey")
- value := []byte("myvalue")
- if err := tx.Metadata().Put(key, value); err != nil {
- return err
- }
-
- // Read the key back and ensure it matches.
- if !bytes.Equal(tx.Metadata().Get(key), value) {
- return fmt.Errorf("unexpected value for key '%s'", key)
- }
-
- // Create a new nested bucket under the metadata bucket.
- nestedBucketKey := []byte("mybucket")
- nestedBucket, err := tx.Metadata().CreateBucket(nestedBucketKey)
- if err != nil {
- return err
- }
-
- // The key from above that was set in the metadata bucket does
- // not exist in this new nested bucket.
- if nestedBucket.Get(key) != nil {
- return fmt.Errorf("key '%s' is not expected nil", key)
- }
-
- return nil
- })
- if err != nil {
- fmt.Println(err)
- return
- }
-
- // Output:
-}
-
-// This example demonstrates creating a new database, using a managed read-write
-// transaction to store a block, and using a managed read-only transaction to
-// fetch the block.
-func Example_blockStorageAndRetrieval() {
- // This example assumes the ffldb driver is imported.
- //
- // import (
- // "github.com/btcsuite/btcd/database"
- // _ "github.com/btcsuite/btcd/database/ffldb"
- // )
-
- // Create a database and schedule it to be closed and removed on exit.
- // Typically you wouldn't want to remove the database right away like
- // this, nor put it in the temp directory, but it's done here to ensure
- // the example cleans up after itself.
- dbPath := filepath.Join(os.TempDir(), "exampleblkstorage")
- db, err := database.Create("ffldb", dbPath, wire.MainNet)
- if err != nil {
- fmt.Println(err)
- return
- }
- defer os.RemoveAll(dbPath)
- defer db.Close()
-
- // Use the Update function of the database to perform a managed
- // read-write transaction and store a genesis block in the database as
- // and example.
- err = db.Update(func(tx database.Tx) error {
- genesisBlock := chaincfg.MainNetParams.GenesisBlock
- return tx.StoreBlock(btcutil.NewBlock(genesisBlock))
- })
- if err != nil {
- fmt.Println(err)
- return
- }
-
- // Use the View function of the database to perform a managed read-only
- // transaction and fetch the block stored above.
- var loadedBlockBytes []byte
- err = db.Update(func(tx database.Tx) error {
- genesisHash := chaincfg.MainNetParams.GenesisHash
- blockBytes, err := tx.FetchBlock(genesisHash)
- if err != nil {
- return err
- }
-
- // As documented, all data fetched from the database is only
- // valid during a database transaction in order to support
- // zero-copy backends. Thus, make a copy of the data so it
- // can be used outside of the transaction.
- loadedBlockBytes = make([]byte, len(blockBytes))
- copy(loadedBlockBytes, blockBytes)
- return nil
- })
- if err != nil {
- fmt.Println(err)
- return
- }
-
- // Typically at this point, the block could be deserialized via the
- // wire.MsgBlock.Deserialize function or used in its serialized form
- // depending on need. However, for this example, just display the
- // number of serialized bytes to show it was loaded as expected.
- fmt.Printf("Serialized block size: %d bytes\n", len(loadedBlockBytes))
-
- // Output:
- // Serialized block size: 285 bytes
-}
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