chore: import upstream snapshot with attribution

store/file.go

@@ -0,0 +1,445 @@
+package store
+
+import (
+	"context"
+	"encoding/json"
+	"os"
+	"path/filepath"
+	"sort"
+	"strings"
+	"sync"
+	"time"
+
+	bolt "go.etcd.io/bbolt"
+)
+
+var (
+	HomeDir, _ = os.UserHomeDir()
+
+	// DefaultDatabase is the namespace that the bbolt store
+	// will use if no namespace is provided.
+	DefaultDatabase = "micro"
+	// DefaultTable when none is specified.
+	DefaultTable = "micro"
+	// DefaultDir is the default directory for bbolt files.
+	DefaultDir = filepath.Join(HomeDir, "micro", "store")
+
+	// bucket used for data storage.
+	dataBucket = "data"
+)
+
+func NewFileStore(opts ...Option) Store {
+	s := &fileStore{
+		handles: make(map[string]*fileHandle),
+	}
+	_ = s.init(opts...)
+	return s
+}
+
+type fileStore struct {
+	options Options
+	dir     string
+
+	// the database handle
+	sync.RWMutex
+	handles map[string]*fileHandle
+}
+
+type fileHandle struct {
+	key string
+	db  *bolt.DB
+}
+
+// record stored by us.
+type record struct {
+	Key       string
+	Value     []byte
+	Metadata  map[string]interface{}
+	ExpiresAt time.Time
+}
+
+func key(database, table string) string {
+	return database + ":" + table
+}
+
+func (m *fileStore) delete(fd *fileHandle, key string) error {
+	return fd.db.Update(func(tx *bolt.Tx) error {
+		b := tx.Bucket([]byte(dataBucket))
+		if b == nil {
+			return nil
+		}
+		return b.Delete([]byte(key))
+	})
+}
+
+func (m *fileStore) init(opts ...Option) error {
+	for _, o := range opts {
+		o(&m.options)
+	}
+
+	if m.options.Database == "" {
+		m.options.Database = DefaultDatabase
+	}
+
+	if m.options.Table == "" {
+		// bbolt requires bucketname to not be empty
+		m.options.Table = DefaultTable
+	}
+
+	if m.options.Context != nil {
+		if dir, ok := m.options.Context.Value(dirOptionKey{}).(string); ok {
+			m.dir = dir
+		}
+	}
+
+	// create default directory
+	if m.dir == "" {
+		m.dir = DefaultDir
+	}
+	// create the directory
+	return os.MkdirAll(m.dir, 0700)
+}
+
+func (m *fileStore) getDB(database, table string) (*fileHandle, error) {
+	if len(database) == 0 {
+		database = m.options.Database
+	}
+	if len(table) == 0 {
+		table = m.options.Table
+	}
+
+	k := key(database, table)
+	m.RLock()
+	fd, ok := m.handles[k]
+	m.RUnlock()
+
+	// return the file handle
+	if ok {
+		return fd, nil
+	}
+
+	// double check locking
+	m.Lock()
+	defer m.Unlock()
+	if fd, ok := m.handles[k]; ok {
+		return fd, nil
+	}
+
+	// create directory
+	dir := filepath.Join(m.dir, database)
+	// create the database handle
+	fname := table + ".db"
+	// make the dir
+	_ = os.MkdirAll(dir, 0700)
+	// database path
+	dbPath := filepath.Join(dir, fname)
+
+	// create new db handle
+	// Bolt DB only allows one process to open the file R/W so make sure we're doing this under a lock
+	db, err := bolt.Open(dbPath, 0700, &bolt.Options{Timeout: 5 * time.Second})
+	if err != nil {
+		return nil, err
+	}
+	fd = &fileHandle{
+		key: k,
+		db:  db,
+	}
+	m.handles[k] = fd
+
+	return fd, nil
+}
+
+func (m *fileStore) list(fd *fileHandle, limit, offset uint) []string {
+	var allItems []string
+
+	_ = fd.db.View(func(tx *bolt.Tx) error {
+		b := tx.Bucket([]byte(dataBucket))
+		// nothing to read
+		if b == nil {
+			return nil
+		}
+
+		// @todo very inefficient
+		if err := b.ForEach(func(k, v []byte) error {
+			storedRecord := &record{}
+
+			if err := json.Unmarshal(v, storedRecord); err != nil {
+				return err
+			}
+
+			if !storedRecord.ExpiresAt.IsZero() {
+				if storedRecord.ExpiresAt.Before(time.Now()) {
+					return nil
+				}
+			}
+
+			allItems = append(allItems, string(k))
+
+			return nil
+		}); err != nil {
+			return err
+		}
+
+		return nil
+	})
+
+	allKeys := make([]string, len(allItems))
+
+	copy(allKeys, allItems)
+
+	if limit != 0 || offset != 0 {
+		sort.Slice(allKeys, func(i, j int) bool { return allKeys[i] < allKeys[j] })
+		min := func(i, j uint) uint {
+			if i < j {
+				return i
+			}
+			return j
+		}
+		return allKeys[offset:min(limit, uint(len(allKeys)))]
+	}
+
+	return allKeys
+}
+
+func (m *fileStore) get(fd *fileHandle, k string) (*Record, error) {
+	var value []byte
+
+	_ = fd.db.View(func(tx *bolt.Tx) error {
+		// @todo this is still very experimental...
+		b := tx.Bucket([]byte(dataBucket))
+		if b == nil {
+			return nil
+		}
+
+		value = b.Get([]byte(k))
+		return nil
+	})
+
+	if value == nil {
+		return nil, ErrNotFound
+	}
+
+	storedRecord := &record{}
+
+	if err := json.Unmarshal(value, storedRecord); err != nil {
+		return nil, err
+	}
+
+	newRecord := &Record{}
+	newRecord.Key = storedRecord.Key
+	newRecord.Value = storedRecord.Value
+	newRecord.Metadata = make(map[string]interface{})
+
+	for k, v := range storedRecord.Metadata {
+		newRecord.Metadata[k] = v
+	}
+
+	if !storedRecord.ExpiresAt.IsZero() {
+		if storedRecord.ExpiresAt.Before(time.Now()) {
+			return nil, ErrNotFound
+		}
+		newRecord.Expiry = time.Until(storedRecord.ExpiresAt)
+	}
+
+	return newRecord, nil
+}
+
+func (m *fileStore) set(fd *fileHandle, r *Record) error {
+	// copy the incoming record and then
+	// convert the expiry in to a hard timestamp
+	item := &record{}
+	item.Key = r.Key
+	item.Value = r.Value
+	item.Metadata = make(map[string]interface{})
+
+	if r.Expiry != 0 {
+		item.ExpiresAt = time.Now().Add(r.Expiry)
+	}
+
+	for k, v := range r.Metadata {
+		item.Metadata[k] = v
+	}
+
+	// marshal the data
+	data, _ := json.Marshal(item)
+
+	return fd.db.Update(func(tx *bolt.Tx) error {
+		b := tx.Bucket([]byte(dataBucket))
+		if b == nil {
+			var err error
+			b, err = tx.CreateBucketIfNotExists([]byte(dataBucket))
+			if err != nil {
+				return err
+			}
+		}
+		return b.Put([]byte(r.Key), data)
+	})
+}
+
+func (m *fileStore) Close() error {
+	m.Lock()
+	defer m.Unlock()
+	for k, v := range m.handles {
+		v.db.Close()
+		delete(m.handles, k)
+	}
+	return nil
+}
+
+func (m *fileStore) Init(opts ...Option) error {
+	return m.init(opts...)
+}
+
+func (m *fileStore) Delete(key string, opts ...DeleteOption) error {
+	var deleteOptions DeleteOptions
+	for _, o := range opts {
+		o(&deleteOptions)
+	}
+
+	fd, err := m.getDB(deleteOptions.Database, deleteOptions.Table)
+	if err != nil {
+		return err
+	}
+
+	return m.delete(fd, key)
+}
+
+func (m *fileStore) Read(key string, opts ...ReadOption) ([]*Record, error) {
+	var readOpts ReadOptions
+	for _, o := range opts {
+		o(&readOpts)
+	}
+
+	fd, err := m.getDB(readOpts.Database, readOpts.Table)
+	if err != nil {
+		return nil, err
+	}
+
+	var keys []string
+
+	// Handle Prefix / suffix
+	// TODO: do range scan here rather than listing all keys
+	if readOpts.Prefix || readOpts.Suffix {
+		// list the keys
+		k := m.list(fd, readOpts.Limit, readOpts.Offset)
+
+		// check for prefix and suffix
+		for _, v := range k {
+			if readOpts.Prefix && !strings.HasPrefix(v, key) {
+				continue
+			}
+			if readOpts.Suffix && !strings.HasSuffix(v, key) {
+				continue
+			}
+			keys = append(keys, v)
+		}
+	} else {
+		keys = []string{key}
+	}
+
+	var results []*Record
+
+	for _, k := range keys {
+		r, err := m.get(fd, k)
+		if err != nil {
+			return results, err
+		}
+		results = append(results, r)
+	}
+
+	return results, nil
+}
+
+func (m *fileStore) Write(r *Record, opts ...WriteOption) error {
+	var writeOpts WriteOptions
+	for _, o := range opts {
+		o(&writeOpts)
+	}
+
+	fd, err := m.getDB(writeOpts.Database, writeOpts.Table)
+	if err != nil {
+		return err
+	}
+
+	if len(opts) > 0 {
+		// Copy the record before applying options, or the incoming record will be mutated
+		newRecord := Record{}
+		newRecord.Key = r.Key
+		newRecord.Value = r.Value
+		newRecord.Metadata = make(map[string]interface{})
+		newRecord.Expiry = r.Expiry
+
+		if !writeOpts.Expiry.IsZero() {
+			newRecord.Expiry = time.Until(writeOpts.Expiry)
+		}
+		if writeOpts.TTL != 0 {
+			newRecord.Expiry = writeOpts.TTL
+		}
+
+		for k, v := range r.Metadata {
+			newRecord.Metadata[k] = v
+		}
+
+		return m.set(fd, &newRecord)
+	}
+
+	return m.set(fd, r)
+}
+
+func (m *fileStore) Options() Options {
+	return m.options
+}
+
+func (m *fileStore) List(opts ...ListOption) ([]string, error) {
+	var listOptions ListOptions
+
+	for _, o := range opts {
+		o(&listOptions)
+	}
+
+	fd, err := m.getDB(listOptions.Database, listOptions.Table)
+	if err != nil {
+		return nil, err
+	}
+
+	// TODO apply prefix/suffix in range query
+	allKeys := m.list(fd, listOptions.Limit, listOptions.Offset)
+
+	if len(listOptions.Prefix) > 0 {
+		var prefixKeys []string
+		for _, k := range allKeys {
+			if strings.HasPrefix(k, listOptions.Prefix) {
+				prefixKeys = append(prefixKeys, k)
+			}
+		}
+		allKeys = prefixKeys
+	}
+
+	if len(listOptions.Suffix) > 0 {
+		var suffixKeys []string
+		for _, k := range allKeys {
+			if strings.HasSuffix(k, listOptions.Suffix) {
+				suffixKeys = append(suffixKeys, k)
+			}
+		}
+		allKeys = suffixKeys
+	}
+
+	return allKeys, nil
+}
+
+func (m *fileStore) String() string {
+	return "file"
+}
+
+type dirOptionKey struct{}
+
+// DirOption is a file store Option to set the directory for the file
+func DirOption(dir string) Option {
+	return func(o *Options) {
+		if o.Context == nil {
+			o.Context = context.Background()
+		}
+		o.Context = context.WithValue(o.Context, dirOptionKey{}, dir)
+	}
+}