OP#792 initial commit after fork

cmd/metacache-marker.go

@@ -0,0 +1,90 @@
+// Copyright (c) 2015-2021 MinIO, Inc.
+//
+// This file is part of MinIO Object Storage stack
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package cmd
+
+import (
+	"context"
+	"fmt"
+	"strconv"
+	"strings"
+)
+
+// markerTagVersion is the marker version.
+// Should not need to be updated unless a fundamental change is made to the marker format.
+const markerTagVersion = "v2"
+
+// parseMarker will parse a marker possibly encoded with encodeMarker
+func (o *listPathOptions) parseMarker() {
+	s := o.Marker
+	if !strings.Contains(s, "[minio_cache:"+markerTagVersion) {
+		return
+	}
+	start := strings.LastIndex(s, "[")
+	o.Marker = s[:start]
+	end := strings.LastIndex(s, "]")
+	tag := strings.Trim(s[start:end], "[]")
+	tags := strings.SplitSeq(tag, ",")
+	for tag := range tags {
+		kv := strings.Split(tag, ":")
+		if len(kv) < 2 {
+			continue
+		}
+		switch kv[0] {
+		case "minio_cache":
+			if kv[1] != markerTagVersion {
+				continue
+			}
+		case "id":
+			o.ID = kv[1]
+		case "return":
+			o.ID = mustGetUUID()
+			o.Create = true
+		case "p": // pool
+			v, err := strconv.ParseInt(kv[1], 10, 64)
+			if err != nil {
+				o.ID = mustGetUUID()
+				o.Create = true
+				continue
+			}
+			o.pool = int(v)
+		case "s": // set
+			v, err := strconv.ParseInt(kv[1], 10, 64)
+			if err != nil {
+				o.ID = mustGetUUID()
+				o.Create = true
+				continue
+			}
+			o.set = int(v)
+		default:
+			// Ignore unknown
+		}
+	}
+}
+
+// encodeMarker will encode a uuid and return it as a marker.
+// uuid cannot contain '[', ':' or ','.
+func (o listPathOptions) encodeMarker(marker string) string {
+	if o.ID == "" {
+		// Mark as returning listing...
+		return fmt.Sprintf("%s[minio_cache:%s,return:]", marker, markerTagVersion)
+	}
+	if strings.ContainsAny(o.ID, "[:,") {
+		internalLogIf(context.Background(), fmt.Errorf("encodeMarker: uuid %s contained invalid characters", o.ID))
+	}
+	return fmt.Sprintf("%s[minio_cache:%s,id:%s,p:%d,s:%d]", marker, markerTagVersion, o.ID, o.pool, o.set)
+}