streamdata: iterator over known idents

Useful for searching.

Signed-off-by: Yonah <contrib@gensokyo.uk>

streamdata.go

@@ -6,11 +6,15 @@ import (
 	"encoding/json"
 	"errors"
 	"io"
+	"io/fs"
+	"iter"
 	"os"
 	"path"
 	"strconv"
+	"strings"
 	"syscall"
 	"time"
+	"unsafe"
 )
 
 // Channel represents a Twitch channel.
@@ -198,6 +202,38 @@ func (c *Channel) Add(ident *Ident, f func(v *VOD, w io.Writer) error) error {
 	return nil
 }
 
+// All returns an iterator over all known [Ident] in the on-disk representation.
+// Iteration stops when encountering the first non-nil error, and its value is
+// saved to the value pointed to by errP.
+func (c *Channel) All(errP *error) iter.Seq[*Ident] {
+	return func(yield func(*Ident) bool) {
+		dents, err := c.root.FS().(fs.ReadDirFS).ReadDir(channelPathVOD)
+		if err != nil {
+			*errP = err
+			return
+		}
+
+		var ident Ident
+		for _, dent := range dents {
+			name := dent.Name()
+			if strings.HasSuffix(name, ChannelVODSuffix) {
+				continue
+			}
+
+			if err = ident.UnmarshalText(
+				unsafe.Slice(unsafe.StringData(name), len(name)),
+			); err != nil {
+				*errP = err
+				return
+			}
+
+			if !yield(&ident) {
+				return
+			}
+		}
+	}
+}
+
 // Load loads the metadata of a [VOD] by [Ident] and returns its address.
 func (c *Channel) Load(ident *Ident) (*VOD, error) {
 	var v VOD