diff options
Diffstat (limited to '')
| -rw-r--r-- | models/dbfs/dbfile.go | 368 |
1 files changed, 368 insertions, 0 deletions
diff --git a/models/dbfs/dbfile.go b/models/dbfs/dbfile.go new file mode 100644 index 0000000..dd27b5c --- /dev/null +++ b/models/dbfs/dbfile.go @@ -0,0 +1,368 @@ +// Copyright 2022 The Gitea Authors. All rights reserved. +// SPDX-License-Identifier: MIT + +package dbfs + +import ( + "context" + "errors" + "io" + "io/fs" + "os" + "path/filepath" + "strconv" + "strings" + "time" + + "code.gitea.io/gitea/models/db" +) + +var defaultFileBlockSize int64 = 32 * 1024 + +type File interface { + io.ReadWriteCloser + io.Seeker + fs.File +} + +type file struct { + ctx context.Context + metaID int64 + fullPath string + blockSize int64 + + allowRead bool + allowWrite bool + offset int64 +} + +var _ File = (*file)(nil) + +func (f *file) readAt(fileMeta *dbfsMeta, offset int64, p []byte) (n int, err error) { + if offset >= fileMeta.FileSize { + return 0, io.EOF + } + + blobPos := int(offset % f.blockSize) + blobOffset := offset - int64(blobPos) + blobRemaining := int(f.blockSize) - blobPos + needRead := len(p) + if needRead > blobRemaining { + needRead = blobRemaining + } + if blobOffset+int64(blobPos)+int64(needRead) > fileMeta.FileSize { + needRead = int(fileMeta.FileSize - blobOffset - int64(blobPos)) + } + if needRead <= 0 { + return 0, io.EOF + } + var fileData dbfsData + ok, err := db.GetEngine(f.ctx).Where("meta_id = ? AND blob_offset = ?", f.metaID, blobOffset).Get(&fileData) + if err != nil { + return 0, err + } + blobData := fileData.BlobData + if !ok { + blobData = nil + } + + canCopy := len(blobData) - blobPos + if canCopy <= 0 { + canCopy = 0 + } + realRead := needRead + if realRead > canCopy { + realRead = canCopy + } + if realRead > 0 { + copy(p[:realRead], fileData.BlobData[blobPos:blobPos+realRead]) + } + for i := realRead; i < needRead; i++ { + p[i] = 0 + } + return needRead, nil +} + +func (f *file) Read(p []byte) (n int, err error) { + if f.metaID == 0 || !f.allowRead { + return 0, os.ErrInvalid + } + + fileMeta, err := findFileMetaByID(f.ctx, f.metaID) + if err != nil { + return 0, err + } + n, err = f.readAt(fileMeta, f.offset, p) + f.offset += int64(n) + return n, err +} + +func (f *file) Write(p []byte) (n int, err error) { + if f.metaID == 0 || !f.allowWrite { + return 0, os.ErrInvalid + } + + fileMeta, err := findFileMetaByID(f.ctx, f.metaID) + if err != nil { + return 0, err + } + + needUpdateSize := false + written := 0 + for len(p) > 0 { + blobPos := int(f.offset % f.blockSize) + blobOffset := f.offset - int64(blobPos) + blobRemaining := int(f.blockSize) - blobPos + needWrite := len(p) + if needWrite > blobRemaining { + needWrite = blobRemaining + } + buf := make([]byte, f.blockSize) + readBytes, err := f.readAt(fileMeta, blobOffset, buf) + if err != nil && !errors.Is(err, io.EOF) { + return written, err + } + copy(buf[blobPos:blobPos+needWrite], p[:needWrite]) + if blobPos+needWrite > readBytes { + buf = buf[:blobPos+needWrite] + } else { + buf = buf[:readBytes] + } + + fileData := dbfsData{ + MetaID: fileMeta.ID, + BlobOffset: blobOffset, + BlobData: buf, + } + if res, err := db.GetEngine(f.ctx).Exec("UPDATE dbfs_data SET revision=revision+1, blob_data=? WHERE meta_id=? AND blob_offset=?", buf, fileMeta.ID, blobOffset); err != nil { + return written, err + } else if updated, err := res.RowsAffected(); err != nil { + return written, err + } else if updated == 0 { + if _, err = db.GetEngine(f.ctx).Insert(&fileData); err != nil { + return written, err + } + } + written += needWrite + f.offset += int64(needWrite) + if f.offset > fileMeta.FileSize { + fileMeta.FileSize = f.offset + needUpdateSize = true + } + p = p[needWrite:] + } + + fileMetaUpdate := dbfsMeta{ + ModifyTimestamp: timeToFileTimestamp(time.Now()), + } + if needUpdateSize { + fileMetaUpdate.FileSize = f.offset + } + if _, err := db.GetEngine(f.ctx).ID(fileMeta.ID).Update(fileMetaUpdate); err != nil { + return written, err + } + return written, nil +} + +func (f *file) Seek(n int64, whence int) (int64, error) { + if f.metaID == 0 { + return 0, os.ErrInvalid + } + + newOffset := f.offset + switch whence { + case io.SeekStart: + newOffset = n + case io.SeekCurrent: + newOffset += n + case io.SeekEnd: + size, err := f.size() + if err != nil { + return f.offset, err + } + newOffset = size + n + default: + return f.offset, os.ErrInvalid + } + if newOffset < 0 { + return f.offset, os.ErrInvalid + } + f.offset = newOffset + return newOffset, nil +} + +func (f *file) Close() error { + return nil +} + +func (f *file) Stat() (os.FileInfo, error) { + if f.metaID == 0 { + return nil, os.ErrInvalid + } + + fileMeta, err := findFileMetaByID(f.ctx, f.metaID) + if err != nil { + return nil, err + } + return fileMeta, nil +} + +func timeToFileTimestamp(t time.Time) int64 { + return t.UnixMicro() +} + +func fileTimestampToTime(timestamp int64) time.Time { + return time.UnixMicro(timestamp) +} + +func (f *file) loadMetaByPath() error { + var fileMeta dbfsMeta + if ok, err := db.GetEngine(f.ctx).Where("full_path = ?", f.fullPath).Get(&fileMeta); err != nil { + return err + } else if ok { + f.metaID = fileMeta.ID + f.blockSize = fileMeta.BlockSize + } + return nil +} + +func (f *file) open(flag int) (err error) { + // see os.OpenFile for flag values + if flag&os.O_WRONLY != 0 { + f.allowWrite = true + } else if flag&os.O_RDWR != 0 { + f.allowRead = true + f.allowWrite = true + } else /* O_RDONLY */ { + f.allowRead = true + } + + if f.allowWrite { + if flag&os.O_CREATE != 0 { + if flag&os.O_EXCL != 0 { + // file must not exist. + if f.metaID != 0 { + return os.ErrExist + } + } else { + // create a new file if none exists. + if f.metaID == 0 { + if err = f.createEmpty(); err != nil { + return err + } + } + } + } + if flag&os.O_TRUNC != 0 { + if err = f.truncate(); err != nil { + return err + } + } + if flag&os.O_APPEND != 0 { + if _, err = f.Seek(0, io.SeekEnd); err != nil { + return err + } + } + return nil + } + + // read only mode + if f.metaID == 0 { + return os.ErrNotExist + } + return nil +} + +func (f *file) createEmpty() error { + if f.metaID != 0 { + return os.ErrExist + } + now := time.Now() + _, err := db.GetEngine(f.ctx).Insert(&dbfsMeta{ + FullPath: f.fullPath, + BlockSize: f.blockSize, + CreateTimestamp: timeToFileTimestamp(now), + ModifyTimestamp: timeToFileTimestamp(now), + }) + if err != nil { + return err + } + return f.loadMetaByPath() +} + +func (f *file) truncate() error { + if f.metaID == 0 { + return os.ErrNotExist + } + return db.WithTx(f.ctx, func(ctx context.Context) error { + if _, err := db.GetEngine(ctx).Exec("UPDATE dbfs_meta SET file_size = 0 WHERE id = ?", f.metaID); err != nil { + return err + } + if _, err := db.GetEngine(ctx).Delete(&dbfsData{MetaID: f.metaID}); err != nil { + return err + } + return nil + }) +} + +func (f *file) renameTo(newPath string) error { + if f.metaID == 0 { + return os.ErrNotExist + } + newPath = buildPath(newPath) + return db.WithTx(f.ctx, func(ctx context.Context) error { + if _, err := db.GetEngine(ctx).Exec("UPDATE dbfs_meta SET full_path = ? WHERE id = ?", newPath, f.metaID); err != nil { + return err + } + return nil + }) +} + +func (f *file) delete() error { + if f.metaID == 0 { + return os.ErrNotExist + } + return db.WithTx(f.ctx, func(ctx context.Context) error { + if _, err := db.GetEngine(ctx).Delete(&dbfsMeta{ID: f.metaID}); err != nil { + return err + } + if _, err := db.GetEngine(ctx).Delete(&dbfsData{MetaID: f.metaID}); err != nil { + return err + } + return nil + }) +} + +func (f *file) size() (int64, error) { + if f.metaID == 0 { + return 0, os.ErrNotExist + } + fileMeta, err := findFileMetaByID(f.ctx, f.metaID) + if err != nil { + return 0, err + } + return fileMeta.FileSize, nil +} + +func findFileMetaByID(ctx context.Context, metaID int64) (*dbfsMeta, error) { + var fileMeta dbfsMeta + if ok, err := db.GetEngine(ctx).Where("id = ?", metaID).Get(&fileMeta); err != nil { + return nil, err + } else if ok { + return &fileMeta, nil + } + return nil, nil +} + +func buildPath(path string) string { + path = filepath.Clean(path) + path = strings.ReplaceAll(path, "\\", "/") + path = strings.TrimPrefix(path, "/") + return strconv.Itoa(strings.Count(path, "/")) + ":" + path +} + +func newDbFile(ctx context.Context, path string) (*file, error) { + path = buildPath(path) + f := &file{ctx: ctx, fullPath: path, blockSize: defaultFileBlockSize} + return f, f.loadMetaByPath() +} |