New cache format using gzip compression

1 files changed, 63 insertions, 0 deletions

diff --git a/internal/feed/cache/v2.go b/internal/feed/cache/v2.go
new file mode 100644
index 0000000..87636b6
--- /dev/null
+++ b/internal/feed/cache/v2.go
@@ -0,0 +1,63 @@
+package cache
+
+import (
+	"compress/gzip"
+	"fmt"
+	"io"
+
+	"github.com/Necoro/feed2imap-go/internal/feed"
+)
+
+const v2Version Version = 2
+
+// v2Cache is identical to v1Cache, but uses gzip compression for storage
+type v2Cache v1Cache
+
+func newV2Cache() *v2Cache {
+	return (*v2Cache)(newV1Cache())
+}
+
+func (cache *v2Cache) asV1() *v1Cache {
+	return (*v1Cache)(cache)
+}
+
+func (cache *v2Cache) cachedFeed(feed *feed.Feed) CachedFeed {
+	return cache.asV1().cachedFeed(feed)
+}
+
+func (cache *v2Cache) transformTo(v Version) (Impl, error) {
+	return nil, fmt.Errorf("Transformation not supported")
+}
+
+func (cache *v2Cache) Version() Version {
+	return v2Version
+}
+
+func (cache *v2Cache) Info() string {
+	return cache.asV1().Info()
+}
+
+func (cache *v2Cache) SpecificInfo(i interface{}) string {
+	return cache.asV1().SpecificInfo(i)
+}
+
+func (cache *v2Cache) load(reader io.Reader) error {
+	gzipReader, err := gzip.NewReader(reader)
+	if err != nil {
+		return err
+	}
+	defer gzipReader.Close()
+
+	return cache.asV1().load(gzipReader)
+}
+
+func (cache *v2Cache) store(writer io.Writer) error {
+	gzipWriter := gzip.NewWriter(writer)
+	defer gzipWriter.Close()
+
+	if err := cache.asV1().store(gzipWriter); err != nil {
+		return err
+	}
+
+	return gzipWriter.Flush()
+}