Upstream versity/versitygw state of the touched files before 95a6da83b9

backend/mp-lister.go

@@ -0,0 +1,205 @@
+// Copyright 2026 Versity Software
+// This file is licensed under the Apache License, Version 2.0
+// (the "License"); you may not use this file except in compliance
+// with the License.  You may obtain a copy of the License at
+//
+//   http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied.  See the License for the
+// specific language governing permissions and limitations
+// under the License.
+
+package backend
+
+import (
+	"strings"
+
+	"github.com/google/uuid"
+	"github.com/versity/versitygw/s3err"
+	"github.com/versity/versitygw/s3response"
+)
+
+// ListMultipartUploads initializes a multipart upload lister and calls Run()
+func ListMultipartUploads(uploads []s3response.Upload, prefix, delimiter, keyMarker, uploadIdMarker string, maxUploads int) (*ListMultipartUploadsPage, error) {
+	lister := &MultipartUploadLister{
+		Uploads:        uploads,
+		Prefix:         prefix,
+		Delimiter:      delimiter,
+		KeyMarker:      keyMarker,
+		UploadIDMarker: uploadIdMarker,
+		MaxUploads:     maxUploads,
+	}
+
+	return lister.Run()
+}
+
+// MultipartUploadLister emits a ListMultipartUploads-compatible page from an
+// already-sorted, already prefix- and key-marker-filtered upload list.
+//
+// Assumptions about input Uploads:
+//   - Sorted by (Key asc, Initiated asc)
+//   - Filtered by Prefix
+//   - Filtered to start strictly after key-marker when key-marker was provided.
+type MultipartUploadLister struct {
+	Uploads        []s3response.Upload
+	Prefix         string
+	Delimiter      string
+	MaxUploads     int
+	KeyMarker      string
+	UploadIDMarker string
+}
+
+// ListMultipartUploadsPage is the lister output
+type ListMultipartUploadsPage struct {
+	Uploads            []s3response.Upload
+	CommonPrefixes     []s3response.CommonPrefix
+	IsTruncated        bool
+	NextKeyMarker      string
+	NextUploadIDMarker string
+}
+
+// Run validates marker constraints, then performs a single-pass list that:
+// - collapses uploads into CommonPrefixes when delimiter is set
+// - enforces MaxUploads over (Uploads + CommonPrefixes)
+// - computes truncation and next markers
+func (l *MultipartUploadLister) Run() (*ListMultipartUploadsPage, error) {
+	out := &ListMultipartUploadsPage{}
+
+	var startIndex int
+
+	// if upload-id-marker is provided without a corresponding key-marker, ignore it.
+	uploadIDMarker := l.UploadIDMarker
+	if l.KeyMarker == "" {
+		uploadIDMarker = ""
+	}
+
+	if uploadIDMarker != "" {
+		// any invalid uuid is considered as an invalid uploadIdMarker
+		_, err := uuid.Parse(uploadIDMarker)
+		if err != nil {
+			return nil, s3err.GetInvalidArgumentErr(s3err.InvalidArgUploadIdMarker, uploadIDMarker)
+		}
+		startIndex = l.findUploadIdMarkerIndex(uploadIDMarker)
+		if startIndex == -1 {
+			return nil, s3err.GetInvalidArgumentErr(s3err.InvalidArgUploadIdMarker, uploadIDMarker)
+		}
+		if startIndex >= len(l.Uploads) {
+			return out, nil
+		}
+	}
+
+	// Common prefix uniqueness tracking.
+	seenCP := make(map[string]struct{})
+
+	emitted := 0
+	var lastKey string
+
+	// emitUpload appends a new upload to out.Uplodas
+	emitUpload := func(up s3response.Upload) bool {
+		out.Uploads = append(out.Uploads, up)
+		emitted++
+		lastKey = up.Key
+		return emitted == l.MaxUploads
+	}
+	// emitCp appends a new common prefix to out.CommonPrefixes
+	emitCP := func(cpref string) bool {
+		out.CommonPrefixes = append(out.CommonPrefixes, s3response.CommonPrefix{Prefix: cpref})
+		emitted++
+		lastKey = cpref
+		return emitted == l.MaxUploads
+	}
+
+	for i, up := range l.Uploads[startIndex:] {
+		if l.Delimiter != "" {
+			// delimiter check
+			suffix := strings.TrimPrefix(up.Key, l.Prefix)
+			before, _, found := strings.Cut(suffix, l.Delimiter)
+			if found {
+				cpref := l.Prefix + before + l.Delimiter
+				if _, ok := seenCP[cpref]; !ok {
+					seenCP[cpref] = struct{}{}
+					if emitCP(cpref) {
+						out.IsTruncated = l.hasMoreAfter(i+1, seenCP)
+						if out.IsTruncated {
+							out.NextKeyMarker = lastKey
+							out.NextUploadIDMarker = up.UploadID
+						}
+						return out, nil
+					}
+				}
+				continue
+			}
+		}
+
+		if emitUpload(up) {
+			out.IsTruncated = l.hasMoreAfter(i+1, seenCP)
+			if out.IsTruncated {
+				out.NextKeyMarker = lastKey
+				out.NextUploadIDMarker = up.UploadID
+			}
+			return out, nil
+		}
+	}
+
+	return out, nil
+}
+
+// findUploadIdMarkerIndex finds the index of given uploadId marker in uploads
+// uploadIDMarker must match an upload-id among uploads with the first key after KeyMarker.
+// Since caller filtered to Key > KeyMarker and the list is sorted by key/time,
+// the first key after KeyMarker is Uploads[0].Key (if any).
+// -1 is returned if no uploadId is found
+func (l *MultipartUploadLister) findUploadIdMarkerIndex(uploadIDMarker string) int {
+	if len(l.Uploads) == 0 {
+		// key-marker provided but nothing after it => upload-id-marker can never be valid.
+		return -1
+	}
+	firstKey := l.Uploads[0].Key
+
+	// it must match an upload-id under firstKey only.
+	// If firstKey has multiple uploads, any of those IDs is valid.
+	for i, up := range l.Uploads {
+		if up.Key != firstKey {
+			// sorted by key, so we're past firstKey group
+			break
+		}
+		if up.UploadID == uploadIDMarker {
+			// the listing should start from the next index
+			// to skip the uploadId marker
+			return i + 1
+		}
+	}
+	return -1
+}
+
+// hasMoreAfter checks if there exists at least one more effective item after idx,
+// considering delimiter collapse and already-emitted common prefixes.
+func (l *MultipartUploadLister) hasMoreAfter(idx int, seenCP map[string]struct{}) bool {
+	if idx >= len(l.Uploads) {
+		return false
+	}
+	if l.Delimiter == "" {
+		// any remaining upload would be emitted
+		return true
+	}
+
+	for i := idx; i < len(l.Uploads); i++ {
+		up := l.Uploads[i]
+		suffix := strings.TrimPrefix(up.Key, l.Prefix)
+		before, _, found := strings.Cut(suffix, l.Delimiter)
+		if !found {
+			// would emit an upload
+			return true
+		}
+		cpref := l.Prefix + before + l.Delimiter
+		if _, ok := seenCP[cpref]; ok {
+			continue
+		}
+		// would emit a new common prefix
+		return true
+	}
+	return false
+}