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- // Copyright 2022 The Gitea Authors. All rights reserved.
- // SPDX-License-Identifier: MIT
-
- package dbfs
-
- import (
- "context"
- "errors"
- "io"
- "os"
- "path/filepath"
- "strconv"
- "strings"
- "time"
-
- "code.gitea.io/gitea/models/db"
- )
-
- var defaultFileBlockSize int64 = 32 * 1024
-
- type File interface {
- io.ReadWriteCloser
- io.Seeker
- }
-
- 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 timeToFileTimestamp(t time.Time) int64 {
- return t.UnixMicro()
- }
-
- func (f *file) loadMetaByPath() (*dbfsMeta, error) {
- var fileMeta dbfsMeta
- if ok, err := db.GetEngine(f.ctx).Where("full_path = ?", f.fullPath).Get(&fileMeta); err != nil {
- return nil, err
- } else if ok {
- f.metaID = fileMeta.ID
- f.blockSize = fileMeta.BlockSize
- return &fileMeta, nil
- }
- return nil, 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
- }
- if _, err = f.loadMetaByPath(); err != nil {
- return err
- }
- return nil
- }
-
- 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}
- if _, err := f.loadMetaByPath(); err != nil {
- return nil, err
- }
- return f, nil
- }
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