clipboard: introduce native clipboard, clip-persist, clip-storage functionality

core/internal/clipboard/store.go

@@ -0,0 +1,253 @@
+package clipboard
+
+import (
+	"bytes"
+	"encoding/binary"
+	"fmt"
+	"image"
+	_ "image/gif"
+	_ "image/jpeg"
+	_ "image/png"
+	"os"
+	"path/filepath"
+	"strings"
+	"time"
+
+	_ "golang.org/x/image/bmp"
+	_ "golang.org/x/image/tiff"
+
+	bolt "go.etcd.io/bbolt"
+)
+
+type StoreConfig struct {
+	MaxHistory   int
+	MaxEntrySize int64
+}
+
+func DefaultStoreConfig() StoreConfig {
+	return StoreConfig{
+		MaxHistory:   100,
+		MaxEntrySize: 5 * 1024 * 1024,
+	}
+}
+
+type Entry struct {
+	ID        uint64
+	Data      []byte
+	MimeType  string
+	Preview   string
+	Size      int
+	Timestamp time.Time
+	IsImage   bool
+}
+
+func Store(data []byte, mimeType string) error {
+	return StoreWithConfig(data, mimeType, DefaultStoreConfig())
+}
+
+func StoreWithConfig(data []byte, mimeType string, cfg StoreConfig) error {
+	if len(data) == 0 {
+		return nil
+	}
+	if int64(len(data)) > cfg.MaxEntrySize {
+		return fmt.Errorf("data too large: %d > %d", len(data), cfg.MaxEntrySize)
+	}
+
+	dbPath, err := getDBPath()
+	if err != nil {
+		return fmt.Errorf("get db path: %w", err)
+	}
+
+	db, err := bolt.Open(dbPath, 0644, &bolt.Options{Timeout: 1 * time.Second})
+	if err != nil {
+		return fmt.Errorf("open db: %w", err)
+	}
+	defer db.Close()
+
+	entry := Entry{
+		Data:      data,
+		MimeType:  mimeType,
+		Size:      len(data),
+		Timestamp: time.Now(),
+		IsImage:   IsImageMimeType(mimeType),
+	}
+
+	switch {
+	case entry.IsImage:
+		entry.Preview = imagePreview(data, mimeType)
+	default:
+		entry.Preview = textPreview(data)
+	}
+
+	return db.Update(func(tx *bolt.Tx) error {
+		b, err := tx.CreateBucketIfNotExists([]byte("clipboard"))
+		if err != nil {
+			return err
+		}
+
+		if err := deduplicateInTx(b, data); err != nil {
+			return err
+		}
+
+		id, err := b.NextSequence()
+		if err != nil {
+			return err
+		}
+		entry.ID = id
+
+		encoded, err := encodeEntry(entry)
+		if err != nil {
+			return err
+		}
+
+		if err := b.Put(itob(id), encoded); err != nil {
+			return err
+		}
+
+		return trimLengthInTx(b, cfg.MaxHistory)
+	})
+}
+
+func getDBPath() (string, error) {
+	cacheDir := os.Getenv("XDG_CACHE_HOME")
+	if cacheDir == "" {
+		homeDir, err := os.UserHomeDir()
+		if err != nil {
+			return "", err
+		}
+		cacheDir = filepath.Join(homeDir, ".cache")
+	}
+
+	dbDir := filepath.Join(cacheDir, "dms-clipboard")
+	if err := os.MkdirAll(dbDir, 0700); err != nil {
+		return "", err
+	}
+
+	return filepath.Join(dbDir, "db"), nil
+}
+
+func deduplicateInTx(b *bolt.Bucket, data []byte) error {
+	c := b.Cursor()
+	for k, v := c.Last(); k != nil; k, v = c.Prev() {
+		entry, err := decodeEntry(v)
+		if err != nil {
+			continue
+		}
+		if bytes.Equal(entry.Data, data) {
+			if err := b.Delete(k); err != nil {
+				return err
+			}
+		}
+	}
+	return nil
+}
+
+func trimLengthInTx(b *bolt.Bucket, maxHistory int) error {
+	c := b.Cursor()
+	var count int
+	for k, _ := c.Last(); k != nil; k, _ = c.Prev() {
+		if count < maxHistory {
+			count++
+			continue
+		}
+		if err := b.Delete(k); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func encodeEntry(e Entry) ([]byte, error) {
+	buf := new(bytes.Buffer)
+
+	binary.Write(buf, binary.BigEndian, e.ID)
+	binary.Write(buf, binary.BigEndian, uint32(len(e.Data)))
+	buf.Write(e.Data)
+	binary.Write(buf, binary.BigEndian, uint32(len(e.MimeType)))
+	buf.WriteString(e.MimeType)
+	binary.Write(buf, binary.BigEndian, uint32(len(e.Preview)))
+	buf.WriteString(e.Preview)
+	binary.Write(buf, binary.BigEndian, int32(e.Size))
+	binary.Write(buf, binary.BigEndian, e.Timestamp.Unix())
+	if e.IsImage {
+		buf.WriteByte(1)
+	} else {
+		buf.WriteByte(0)
+	}
+
+	return buf.Bytes(), nil
+}
+
+func decodeEntry(data []byte) (Entry, error) {
+	buf := bytes.NewReader(data)
+	var e Entry
+
+	binary.Read(buf, binary.BigEndian, &e.ID)
+
+	var dataLen uint32
+	binary.Read(buf, binary.BigEndian, &dataLen)
+	e.Data = make([]byte, dataLen)
+	buf.Read(e.Data)
+
+	var mimeLen uint32
+	binary.Read(buf, binary.BigEndian, &mimeLen)
+	mimeBytes := make([]byte, mimeLen)
+	buf.Read(mimeBytes)
+	e.MimeType = string(mimeBytes)
+
+	var prevLen uint32
+	binary.Read(buf, binary.BigEndian, &prevLen)
+	prevBytes := make([]byte, prevLen)
+	buf.Read(prevBytes)
+	e.Preview = string(prevBytes)
+
+	var size int32
+	binary.Read(buf, binary.BigEndian, &size)
+	e.Size = int(size)
+
+	var timestamp int64
+	binary.Read(buf, binary.BigEndian, &timestamp)
+	e.Timestamp = time.Unix(timestamp, 0)
+
+	var isImage byte
+	binary.Read(buf, binary.BigEndian, &isImage)
+	e.IsImage = isImage == 1
+
+	return e, nil
+}
+
+func itob(v uint64) []byte {
+	b := make([]byte, 8)
+	binary.BigEndian.PutUint64(b, v)
+	return b
+}
+
+func textPreview(data []byte) string {
+	text := string(data)
+	text = strings.TrimSpace(text)
+	text = strings.Join(strings.Fields(text), " ")
+
+	if len(text) > 100 {
+		return text[:100] + "…"
+	}
+	return text
+}
+
+func imagePreview(data []byte, format string) string {
+	config, imgFmt, err := image.DecodeConfig(bytes.NewReader(data))
+	if err != nil {
+		return fmt.Sprintf("[[ image %s %s ]]", sizeStr(len(data)), format)
+	}
+	return fmt.Sprintf("[[ image %s %s %dx%d ]]", sizeStr(len(data)), imgFmt, config.Width, config.Height)
+}
+
+func sizeStr(size int) string {
+	units := []string{"B", "KiB", "MiB"}
+	var i int
+	fsize := float64(size)
+	for fsize >= 1024 && i < len(units)-1 {
+		fsize /= 1024
+		i++
+	}
+	return fmt.Sprintf("%.0f %s", fsize, units[i])
+}