WIP: Creating hamt db support

walletdb/hdb/db.go

@@ -0,0 +1,157 @@
+package hdb
+
+import (
+	"errors"
+	"io"
+
+	"github.com/btcsuite/btcwallet/walletdb"
+	hamtcontainer "github.com/simplecoincom/go-ipld-adl-hamt-container"
+)
+
+const (
+	// metadataDbName is the name used for the metadata database.
+	metadataDbName = "metadata"
+)
+
+// db represents a collection of namespaces which are persisted and implements
+// the database.DB interface.  All database access is performed through
+// transactions which are obtained through the specific Namespace.
+type db struct {
+	closed bool // Is the database closed?
+	hdb    *hamtcontainer.HAMTContainer
+}
+
+// Enforce db implements the database.DB interface.
+var _ walletdb.DB = (*db)(nil)
+
+// bucket is an internal type used to represent a collection of key/value pairs
+// and implements the database.Bucket interface.
+type bucket struct {
+	id [4]byte
+}
+
+// ReadBucket opens the root bucket for read only access.  If the bucket
+// described by the key does not exist, nil is returned.
+func (b *bucket) ReadBucket(_ []byte) walletdb.ReadBucket {
+	return nil
+}
+
+// ForEachBucket will iterate through all top level buckets.
+func (b *bucket) ForEachBucket(func(key []byte) error) error {
+	return nil
+}
+
+// Rollback closes the transaction, discarding changes (if any) if the
+// database was modified by a write transaction.
+func (b *bucket) Rollback() error {
+	return nil
+}
+
+// ReadWriteBucket opens the root bucket for read/write access.  If the
+// bucket described by the key does not exist, nil is returned.
+func (b *bucket) ReadWriteBucket(_ []byte) walletdb.ReadWriteBucket {
+	return nil
+}
+
+// CreateTopLevelBucket creates the top level bucket for a key if it
+// does not exist.  The newly-created bucket it returned.
+func (b *bucket) CreateTopLevelBucket(_ []byte) (walletdb.ReadWriteBucket, error) {
+	return nil, nil
+}
+
+// DeleteTopLevelBucket deletes the top level bucket for a key.  This
+// errors if the bucket can not be found or the key keys a single value
+// instead of a bucket.
+func (b *bucket) DeleteTopLevelBucket(_ []byte) error {
+	return nil
+}
+
+// Commit commits all changes that have been on the transaction's root
+// buckets and all of their sub-buckets to persistent storage.
+func (b *bucket) Commit() error {
+	return nil
+}
+
+// OnCommit takes a function closure that will be executed when the
+// transaction successfully gets committed.
+func (b *bucket) OnCommit(func()) {
+
+}
+
+// CreateBucket creates and returns a new nested bucket with the given key.
+//
+// Returns the following errors as required by the interface contract:
+//   - ErrBucketExists if the bucket already exists
+//   - ErrBucketNameRequired if the key is empty
+//   - ErrIncompatibleValue if the key is otherwise invalid for the particular
+//     implementation
+//   - ErrTxNotWritable if attempted against a read-only transaction
+//   - ErrTxClosed if the transaction has already been closed
+//
+// This function is part of the database.Bucket interface implementation.
+func (b *bucket) CreateBucket(_ []byte) (walletdb.ReadWriteBucket, error) {
+	return nil, nil
+}
+
+// BeginReadTx starts a read-only transaction.  Multiple read-only transactions
+// can be started simultaneously while only a single read-write transaction can
+// be started at a time.
+//
+// NOTE: The transaction must be closed by calling Rollbackon it when it is no
+// longer needed.  Failure to do so will result in unclaimed memory.
+//
+// This function is part of the walletdb.DB interface implementation.
+func (db *db) BeginReadTx() (walletdb.ReadTx, error) {
+	return &bucket{id: [4]byte{}}, nil
+}
+
+// BeginReadTx starts a read-write transaction.  Multiple read-only transactions
+// can be started simultaneously while only a single read-write transaction can
+// be started at a time.  The call will block when a read-write transaction is
+// already open.
+//
+// NOTE: The transaction must be closed by calling Rollback or Commit on it when
+// it is no longer needed.  Failure to do so will result in unclaimed memory.
+//
+// This function is part of the walletdb.DB interface implementation.
+func (db *db) BeginReadWriteTx() (walletdb.ReadWriteTx, error) {
+	return &bucket{id: [4]byte{}}, nil
+}
+
+// TODO(eduardonunesp): implement this
+func (db *db) Copy(_ io.Writer) error {
+	return errors.New("Not implemented yet")
+}
+
+// Batch is required by the BatchDB interface
+func (db *db) Batch(fn func(tx walletdb.ReadWriteTx) error) error {
+	return walletdb.Update(db, fn)
+}
+
+// Close cleanly shuts down the database and syncs all data.  It will block
+// until all database transactions have been finalized (rolled back or
+// committed).
+//
+// This function is part of the database.DB interface implementation.
+func (db *db) Close() error {
+	if db.closed {
+		return walletdb.ErrDbNotOpen
+	}
+	db.closed = true
+	return nil
+}
+
+// openDB opens the database at the provided path.  walletdb.ErrDbDoesNotExist
+// is returned if the database doesn't exist and the create flag is not set.
+func openDB(ipfsURL string) (walletdb.DB, error) {
+	_ = ipfsURL
+
+	hdb, err := hamtcontainer.NewHAMTBuilder().Build()
+	if err != nil {
+		return nil, err
+	}
+
+	pdb := &db{hdb: hdb}
+
+	return pdb, nil
+}

walletdb/hdb/driver.go

@@ -0,0 +1,68 @@
+// Copyright (c) 2014 The btcsuite developers
+// Use of this source code is governed by an ISC
+// license that can be found in the LICENSE file.
+
+package hdb
+
+import (
+	"fmt"
+
+	"github.com/btcsuite/btcwallet/walletdb"
+)
+
+const (
+	dbType = "hdb"
+)
+
+// parseArgs parses the arguments from the walletdb Open/Create methods.
+func parseArgs(funcName string, args ...interface{}) (string, error) {
+	if len(args) < 1 {
+		return "", fmt.Errorf("invalid arguments to %s.%s -- "+
+			"expected ipfs url",
+			dbType, funcName)
+	}
+
+	ipfsURL, ok := args[0].(string)
+	if !ok {
+		return "", fmt.Errorf("first argument to %s.%s is "+
+			"invalid -- expected ipfs url", dbType,
+			funcName)
+	}
+
+	return ipfsURL, nil
+}
+
+// openDBDriver is the callback provided during driver registration that opens
+// an existing database for use.
+func openDBDriver(args ...interface{}) (walletdb.DB, error) {
+	dbPath, err := parseArgs("Open", args...)
+	if err != nil {
+		return nil, err
+	}
+
+	return openDB(dbPath)
+}
+
+// createDBDriver is the callback provided during driver registration that
+// creates, initializes, and opens a database for use.
+func createDBDriver(args ...interface{}) (walletdb.DB, error) {
+	dbPath, err := parseArgs("Create", args...)
+	if err != nil {
+		return nil, err
+	}
+
+	return openDB(dbPath)
+}
+
+func init() {
+	// Register the driver.
+	driver := walletdb.Driver{
+		DbType: dbType,
+		Create: createDBDriver,
+		Open:   openDBDriver,
+	}
+	if err := walletdb.RegisterDriver(driver); err != nil {
+		panic(fmt.Sprintf("Failed to regiser database driver '%s': %v",
+			dbType, err))
+	}
+}

walletdb/hdb/driver_test.go

@@ -0,0 +1,4 @@
+package hdb_test
+
+// dbType is the database type name for this driver.
+const dbType = "hdb"

walletdb/hdb/interface_test.go

@@ -0,0 +1,36 @@
+// Copyright (c) 2014 The btcsuite developers
+// Use of this source code is governed by an ISC
+// license that can be found in the LICENSE file.
+
+// This file intended to be copied into each backend driver directory.  Each
+// driver should have their own driver_test.go file which creates a database and
+// invokes the testInterface function in this file to ensure the driver properly
+// implements the interface.  See the bdb backend driver for a working example.
+//
+// NOTE: When copying this file into the backend driver folder, the package name
+// will need to be changed accordingly.
+
+package hdb_test
+
+import (
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/btcsuite/btcwallet/walletdb/walletdbtest"
+)
+
+// TestInterface performs all interfaces tests for this database driver.
+func TestInterface(t *testing.T) {
+	tempDir, err := ioutil.TempDir("", "interfacetest")
+	if err != nil {
+		t.Errorf("unable to create temp dir: %v", err)
+		return
+	}
+	defer os.Remove(tempDir)
+
+	dbPath := filepath.Join(tempDir, "db")
+	defer os.RemoveAll(dbPath)
+	walletdbtest.TestInterface(t, dbType, dbPath)
+}