init: pristine aerc 0.20.0 source

worker/jmap/cache/cache.go

@@ -0,0 +1,109 @@
+package cache
+
+import (
+	"errors"
+	"os"
+	"path"
+	"strings"
+
+	"git.sr.ht/~rjarry/aerc/lib/log"
+	"git.sr.ht/~rjarry/aerc/lib/xdg"
+	"github.com/syndtr/goleveldb/leveldb"
+	"github.com/syndtr/goleveldb/leveldb/util"
+)
+
+type JMAPCache struct {
+	mem      map[string][]byte
+	file     *leveldb.DB
+	blobsDir string
+}
+
+func NewJMAPCache(state, blobs bool, accountName string) *JMAPCache {
+	c := new(JMAPCache)
+	cacheDir := xdg.CachePath()
+	if state && cacheDir != "" {
+		var err error
+		dir := path.Join(cacheDir, "aerc", accountName, "state")
+		_ = os.MkdirAll(dir, 0o700)
+		c.file, err = leveldb.OpenFile(dir, nil)
+		if err != nil {
+			log.Errorf("failed to open goleveldb: %s", err)
+			c.mem = make(map[string][]byte)
+		}
+	} else {
+		c.mem = make(map[string][]byte)
+	}
+	if blobs && cacheDir != "" {
+		c.blobsDir = path.Join(cacheDir, "aerc", accountName, "blobs")
+	}
+	return c
+}
+
+var notfound = errors.New("key not found")
+
+func (c *JMAPCache) get(key string) ([]byte, error) {
+	switch {
+	case c.file != nil:
+		return c.file.Get([]byte(key), nil)
+	case c.mem != nil:
+		value, ok := c.mem[key]
+		if !ok {
+			return nil, notfound
+		}
+		return value, nil
+	}
+	panic("jmap cache with no backend")
+}
+
+func (c *JMAPCache) put(key string, value []byte) error {
+	switch {
+	case c.file != nil:
+		return c.file.Put([]byte(key), value, nil)
+	case c.mem != nil:
+		c.mem[key] = value
+		return nil
+	}
+	panic("jmap cache with no backend")
+}
+
+func (c *JMAPCache) delete(key string) error {
+	switch {
+	case c.file != nil:
+		return c.file.Delete([]byte(key), nil)
+	case c.mem != nil:
+		delete(c.mem, key)
+		return nil
+	}
+	panic("jmap cache with no backend")
+}
+
+func (c *JMAPCache) purge(prefix string) error {
+	switch {
+	case c.file != nil:
+		txn, err := c.file.OpenTransaction()
+		if err != nil {
+			return err
+		}
+		iter := txn.NewIterator(util.BytesPrefix([]byte(prefix)), nil)
+		for iter.Next() {
+			err = txn.Delete(iter.Key(), nil)
+			if err != nil {
+				break
+			}
+		}
+		iter.Release()
+		if err != nil {
+			txn.Discard()
+			return err
+		}
+		return txn.Commit()
+	case c.mem != nil:
+		for key := range c.mem {
+			if strings.HasPrefix(key, prefix) {
+				delete(c.mem, key)
+			}
+		}
+		return nil
+	}
+	panic("jmap cache with no backend")
+}