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| 1 | +// Copyright 2024 The Gitea Authors. All rights reserved. |
| 2 | +// SPDX-License-Identifier: MIT |
| 3 | + |
| 4 | +package backend |
| 5 | + |
| 6 | +import ( |
| 7 | + "context" |
| 8 | + "crypto/sha256" |
| 9 | + "encoding/hex" |
| 10 | + "errors" |
| 11 | + "fmt" |
| 12 | + "io" |
| 13 | + |
| 14 | + git_model "code.gitea.io/gitea/models/git" |
| 15 | + repo_model "code.gitea.io/gitea/models/repo" |
| 16 | + "code.gitea.io/gitea/modules/lfs" |
| 17 | + "code.gitea.io/gitea/modules/lfstransfer/transfer" |
| 18 | +) |
| 19 | + |
| 20 | +// Version is the git-lfs-transfer protocol version number. |
| 21 | +const Version = "1" |
| 22 | + |
| 23 | +// Capabilities is a list of Git LFS capabilities supported by this package. |
| 24 | +var Capabilities = []string{ |
| 25 | + "version=" + Version, |
| 26 | + // "locking", // no support yet in gitea backend |
| 27 | +} |
| 28 | + |
| 29 | +// GiteaBackend is an adapter between git-lfs-transfer library and Gitea's internal LFS API |
| 30 | +type GiteaBackend struct { |
| 31 | + ctx context.Context |
| 32 | + repo *repo_model.Repository |
| 33 | + store *lfs.ContentStore |
| 34 | +} |
| 35 | + |
| 36 | +var _ transfer.Backend = &GiteaBackend{} |
| 37 | + |
| 38 | +// Batch implements transfer.Backend |
| 39 | +func (g *GiteaBackend) Batch(_ string, pointers []transfer.BatchItem, _ transfer.Args) ([]transfer.BatchItem, error) { |
| 40 | + for i := range pointers { |
| 41 | + pointers[i].Present = false |
| 42 | + pointer := lfs.Pointer{Oid: pointers[i].Oid, Size: pointers[i].Size} |
| 43 | + exists, err := g.store.Verify(pointer) |
| 44 | + if err != nil || !exists { |
| 45 | + continue |
| 46 | + } |
| 47 | + accessible, err := g.repoHasAccess(pointers[i].Oid) |
| 48 | + if err != nil || !accessible { |
| 49 | + continue |
| 50 | + } |
| 51 | + pointers[i].Present = true |
| 52 | + } |
| 53 | + return pointers, nil |
| 54 | +} |
| 55 | + |
| 56 | +// Download implements transfer.Backend. The returned reader must be closed by the |
| 57 | +// caller. |
| 58 | +func (g *GiteaBackend) Download(oid string, _ transfer.Args) (io.ReadCloser, int64, error) { |
| 59 | + pointer := lfs.Pointer{Oid: oid} |
| 60 | + pointer, err := g.store.GetMeta(pointer) |
| 61 | + if errors.Is(err, lfs.ErrObjectNotInStore) { |
| 62 | + return nil, 0, transfer.ErrNotFound |
| 63 | + } |
| 64 | + if err != nil { |
| 65 | + return nil, 0, err |
| 66 | + } |
| 67 | + obj, err := g.store.Get(pointer) |
| 68 | + if err != nil { |
| 69 | + return nil, 0, err |
| 70 | + } |
| 71 | + accessible, err := g.repoHasAccess(oid) |
| 72 | + if err != nil { |
| 73 | + return nil, 0, err |
| 74 | + } |
| 75 | + if !accessible { |
| 76 | + return nil, 0, transfer.ErrNotFound |
| 77 | + } |
| 78 | + return obj, pointer.Size, nil |
| 79 | +} |
| 80 | + |
| 81 | +// StartUpload implements transfer.Backend. |
| 82 | +func (g *GiteaBackend) Upload(oid string, size int64, r io.Reader, _ transfer.Args) error { |
| 83 | + if r == nil { |
| 84 | + return fmt.Errorf("%w: received null data", transfer.ErrMissingData) |
| 85 | + } |
| 86 | + pointer := lfs.Pointer{Oid: oid, Size: size} |
| 87 | + exists, err := g.store.Verify(pointer) |
| 88 | + if err != nil { |
| 89 | + return err |
| 90 | + } |
| 91 | + if exists { |
| 92 | + accessible, err := g.repoHasAccess(oid) |
| 93 | + if err != nil { |
| 94 | + return err |
| 95 | + } |
| 96 | + if accessible { |
| 97 | + // we already have this object in the store and metadata |
| 98 | + return nil |
| 99 | + } |
| 100 | + // we have this object in the store but not accessible |
| 101 | + // so verify hash and size, and add it to metadata |
| 102 | + hash := sha256.New() |
| 103 | + written, err := io.Copy(hash, r) |
| 104 | + if err != nil { |
| 105 | + return fmt.Errorf("error hashing data: %w", err) |
| 106 | + } |
| 107 | + recvOid := hex.EncodeToString(hash.Sum(nil)) |
| 108 | + if written != size { |
| 109 | + return fmt.Errorf("%w: size mismatch: expected %v", transfer.ErrCorruptData, size) |
| 110 | + } |
| 111 | + if recvOid != oid { |
| 112 | + return fmt.Errorf("%w: OID mismatch: expected %v", transfer.ErrCorruptData, oid) |
| 113 | + } |
| 114 | + } else { |
| 115 | + err = g.store.Put(pointer, r) |
| 116 | + if errors.Is(err, lfs.ErrSizeMismatch) { |
| 117 | + return fmt.Errorf("%w: size mismatch: expected %v", transfer.ErrCorruptData, size) |
| 118 | + } |
| 119 | + if errors.Is(err, lfs.ErrHashMismatch) { |
| 120 | + return fmt.Errorf("%w: OID mismatch: expected %v", transfer.ErrCorruptData, oid) |
| 121 | + } |
| 122 | + if err != nil { |
| 123 | + return err |
| 124 | + } |
| 125 | + } |
| 126 | + _, err = git_model.NewLFSMetaObject(g.ctx, g.repo.ID, pointer) |
| 127 | + if err != nil { |
| 128 | + return fmt.Errorf("could not create LFS Meta Object: %w", err) |
| 129 | + } |
| 130 | + return nil |
| 131 | +} |
| 132 | + |
| 133 | +// Verify implements transfer.Backend. |
| 134 | +func (g *GiteaBackend) Verify(oid string, size int64, args transfer.Args) (transfer.Status, error) { |
| 135 | + pointer := lfs.Pointer{Oid: oid, Size: size} |
| 136 | + exists, err := g.store.Verify(pointer) |
| 137 | + if err != nil { |
| 138 | + return transfer.NewStatus(transfer.StatusNotFound, "not found"), err |
| 139 | + } |
| 140 | + if !exists { |
| 141 | + return transfer.NewStatus(transfer.StatusNotFound, "not found"), transfer.ErrNotFound |
| 142 | + } |
| 143 | + accessible, err := g.repoHasAccess(oid) |
| 144 | + if err != nil { |
| 145 | + return transfer.NewStatus(transfer.StatusNotFound, "not found"), err |
| 146 | + } |
| 147 | + if !accessible { |
| 148 | + return transfer.NewStatus(transfer.StatusNotFound, "not found"), transfer.ErrNotFound |
| 149 | + } |
| 150 | + return transfer.SuccessStatus(), nil |
| 151 | +} |
| 152 | + |
| 153 | +// LockBackend implements transfer.Backend. |
| 154 | +func (g *GiteaBackend) LockBackend(_ transfer.Args) transfer.LockBackend { |
| 155 | + // Gitea doesn't support the locking API |
| 156 | + // this should never be called as we don't advertise the capability |
| 157 | + return (transfer.LockBackend)(nil) |
| 158 | +} |
| 159 | + |
| 160 | +// repoHasAccess checks if the repo already has the object with OID stored |
| 161 | +func (g *GiteaBackend) repoHasAccess(oid string) (bool, error) { |
| 162 | + // check if OID is in global LFS store |
| 163 | + exists, err := g.store.Exists(lfs.Pointer{Oid: oid}) |
| 164 | + if err != nil || !exists { |
| 165 | + return false, err |
| 166 | + } |
| 167 | + // check if OID is in repo LFS store |
| 168 | + metaObj, err := git_model.GetLFSMetaObjectByOid(g.ctx, g.repo.ID, oid) |
| 169 | + if err != nil || metaObj == nil { |
| 170 | + return false, err |
| 171 | + } |
| 172 | + return true, nil |
| 173 | +} |
| 174 | + |
| 175 | +func New(ctx context.Context, r *repo_model.Repository, s *lfs.ContentStore) transfer.Backend { |
| 176 | + return &GiteaBackend{ctx: ctx, repo: r, store: s} |
| 177 | +} |
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