modules/lfs_ssh/transfer: vendor from charmbracelet

Big changes are inevitable due to the difference in Gitea's approach
to storing LFS files. And upstream hasn't tagged for a while anyway.

Author: ConcurrentCrab

go.mod

@@ -37,6 +37,7 @@ require (
 	github.com/ethantkoenig/rupture v1.0.1
 	github.com/felixge/fgprof v0.9.4
 	github.com/fsnotify/fsnotify v1.7.0
+	github.com/git-lfs/pktline v0.0.0-20210330133718-06e9096e2825
 	github.com/gliderlabs/ssh v0.3.7
 	github.com/go-ap/activitypub v0.0.0-20240408091739-ba76b44c2594
 	github.com/go-ap/jsonld v0.0.0-20221030091449-f2a191312c73

go.sum

@@ -276,6 +276,8 @@ github.com/fsnotify/fsnotify v1.7.0 h1:8JEhPFa5W2WU7YfeZzPNqzMP6Lwt7L2715Ggo0nos
 github.com/fsnotify/fsnotify v1.7.0/go.mod h1:40Bi/Hjc2AVfZrqy+aj+yEI+/bRxZnMJyTJwOpGvigM=
 github.com/fxamacker/cbor/v2 v2.6.0 h1:sU6J2usfADwWlYDAFhZBQ6TnLFBHxgesMrQfQgk1tWA=
 github.com/fxamacker/cbor/v2 v2.6.0/go.mod h1:pxXPTn3joSm21Gbwsv0w9OSA2y1HFR9qXEeXQVeNoDQ=
+github.com/git-lfs/pktline v0.0.0-20210330133718-06e9096e2825 h1:riQhgheTL7tMF4d5raz9t3+IzoR1i1wqxE1kZC6dY+U=
+github.com/git-lfs/pktline v0.0.0-20210330133718-06e9096e2825/go.mod h1:fenKRzpXDjNpsIBhuhUzvjCKlDjKam0boRAenTE0Q6A=
 github.com/gliderlabs/ssh v0.3.7 h1:iV3Bqi942d9huXnzEF2Mt+CY9gLu8DNM4Obd+8bODRE=
 github.com/gliderlabs/ssh v0.3.7/go.mod h1:zpHEXBstFnQYtGnB8k8kQLol82umzn/2/snG7alWVD8=
 github.com/glycerine/go-unsnap-stream v0.0.0-20181221182339-f9677308dec2/go.mod h1:/20jfyN9Y5QPEAprSgKAUr+glWDY39ZiUEAYOEv5dsE=

modules/lfs_ssh/transfer/LICENSE

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2022-2023 Charmbracelet, Inc
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

modules/lfs_ssh/transfer/README.md

@@ -0,0 +1,8 @@
+# LFS SSH transfer protocol server
+
+Module vendored from charmbracelet's implementation of the protocol:
+https://github.com/charmbracelet/git-lfs-transfer/
+Modified to suit Gitea's internal LFS API.
+
+MIT Licensed, written by original authors with reference from:
+https://github.com/bk2204/scutiger

modules/lfs_ssh/transfer/args.go

@@ -0,0 +1,50 @@
+package transfer
+
+import (
+	"fmt"
+	"strings"
+)
+
+// batch request argument keys.
+const (
+	HashAlgoKey  = "hash-algo"
+	TransferKey  = "transfer"
+	RefnameKey   = "refname"
+	ExpiresInKey = "expires-in"
+	ExpiresAtKey = "expires-at"
+	SizeKey      = "size"
+	PathKey      = "path"
+	LimitKey     = "limit"
+	CursorKey    = "cursor"
+)
+
+// ParseArgs parses the given args.
+func ParseArgs(parts []string) (Args, error) {
+	args := make(Args, 0)
+	for _, line := range parts {
+		parts := strings.SplitN(line, "=", 2)
+		if len(parts) != 2 {
+			return nil, fmt.Errorf("invalid argument: %q", line)
+		}
+		key, value := parts[0], parts[1]
+		args[key] = value
+	}
+	return args, nil
+}
+
+// ArgsToList converts the given args to a list.
+func ArgsToList(args Args) []string {
+	list := make([]string, 0)
+	for key, value := range args {
+		list = append(list, fmt.Sprintf("%s=%s", key, value))
+	}
+	return list
+}
+
+// Args is a key-value pair of arguments.
+type Args map[string]string
+
+// String returns the string representation of the arguments.
+func (a Args) String() string {
+	return strings.Join(ArgsToList(a), " ")
+}

modules/lfs_ssh/transfer/backend.go

@@ -0,0 +1,45 @@
+package transfer
+
+import (
+	"io"
+	"io/fs"
+)
+
+const (
+	// UploadOperation is an upload operation.
+	UploadOperation = "upload"
+	// DownloadOperation is a download operation.
+	DownloadOperation = "download"
+)
+
+// Backend is a Git LFS backend.
+type Backend interface {
+	Batch(op string, pointers []BatchItem, args Args) ([]BatchItem, error)
+	StartUpload(oid string, r io.Reader, args Args) (io.Closer, error)
+	FinishUpload(state io.Closer, args Args) error
+	Verify(oid string, args Args) (Status, error)
+	Download(oid string, args Args) (fs.File, error)
+	LockBackend(args Args) LockBackend
+}
+
+// Lock is a Git LFS lock.
+type Lock interface {
+	Unlock() error
+	ID() string
+	Path() string
+	FormattedTimestamp() string
+	OwnerName() string
+	AsLockSpec(ownerID bool) ([]string, error)
+	AsArguments() []string
+}
+
+// LockBackend is a Git LFS lock backend.
+type LockBackend interface {
+	// Create creates a lock for the given path and refname.
+	// Refname can be empty.
+	Create(path, refname string) (Lock, error)
+	Unlock(lock Lock) error
+	FromPath(path string) (Lock, error)
+	FromID(id string) (Lock, error)
+	Range(cursor string, limit int, iter func(Lock) error) (string, error)
+}

modules/lfs_ssh/transfer/batch.go

@@ -0,0 +1,12 @@
+package transfer
+
+// BatchItem is a Git LFS batch item.
+type BatchItem struct {
+	Pointer
+
+	// Present is used to determine the action to take for the batch item.
+	Present bool
+
+	// Args is an optional oid-line key-value pairs.
+	Args Args
+}

modules/lfs_ssh/transfer/caps.go

@@ -0,0 +1,10 @@
+package transfer
+
+// Version is the git-lfs-transfer protocol version number.
+const Version = "1"
+
+// Capabilities is a list of Git LFS capabilities supported by this package.
+var Capabilities = []string{
+	"version=" + Version,
+	"locking",
+}

modules/lfs_ssh/transfer/errors.go

@@ -0,0 +1,28 @@
+package transfer
+
+import (
+	"errors"
+)
+
+var (
+	// ErrConflict is the conflict error.
+	ErrConflict = errors.New("conflict")
+	// ErrParseError is the parse error.
+	ErrParseError = errors.New("parse error")
+	// ErrMissingData is the missing data error.
+	ErrMissingData = errors.New("missing data")
+	// ErrExtraData is the extra data error.
+	ErrExtraData = errors.New("extra data")
+	// ErrCorruptData is the corrupt data error.
+	ErrCorruptData = errors.New("corrupt data")
+	// ErrNotAllowed is the not allowed error.
+	ErrNotAllowed = errors.New("not allowed")
+	// ErrInvalidPacket is the invalid packet error.
+	ErrInvalidPacket = errors.New("invalid packet")
+	// ErrNotFound is the not found error.
+	ErrNotFound = errors.New("not found")
+	// ErrUnauthorized is the unauthorized error.
+	ErrUnauthorized = errors.New("unauthorized")
+	// ErrUnauthorized is the forbidden error.
+	ErrForbidden = errors.New("forbidden")
+)

modules/lfs_ssh/transfer/hash.go

@@ -0,0 +1,42 @@
+package transfer
+
+import (
+	"encoding/hex"
+	"hash"
+	"io"
+)
+
+var _ io.Reader = (*HashingReader)(nil)
+
+// HashingReader is a reader that hashes the data it reads.
+type HashingReader struct {
+	r    io.Reader
+	hash hash.Hash
+	size int64
+}
+
+// NewHashingReader creates a new hashing reader.
+func NewHashingReader(r io.Reader, hash hash.Hash) *HashingReader {
+	return &HashingReader{
+		r:    r,
+		hash: hash,
+	}
+}
+
+// Size returns the number of bytes read.
+func (h *HashingReader) Size() int64 {
+	return h.size
+}
+
+// Oid returns the hash of the data read.
+func (h *HashingReader) Oid() string {
+	return hex.EncodeToString(h.hash.Sum(nil))
+}
+
+// Read reads data from the underlying reader and hashes it.
+func (h *HashingReader) Read(p []byte) (int, error) {
+	n, err := h.r.Read(p)
+	h.size += int64(n)
+	h.hash.Write(p[:n])
+	return n, err
+}