// Copyright 2015 The Gogs Authors. All rights reserved.// Copyright 2019 The Gitea Authors. All rights reserved.// SPDX-License-Identifier: MIT package git import (	"bufio"	"bytes"	"encoding/base64"	"fmt"	"io" 	"forgejo.org/modules/log"	"forgejo.org/modules/typesniffer") // Blob represents a Git object.type Blob struct {	ID ObjectID 	gotSize bool	size    int64	name    string	repo    *Repository} func (b *Blob) newReader() (*bufio.Reader, int64, func(), error) {	wr, rd, cancel, err := b.repo.CatFileBatch(b.repo.Ctx)	if err != nil {		return nil, 0, nil, err	} 	_, err = wr.Write([]byte(b.ID.String() + "\n"))	if err != nil {		cancel()		return nil, 0, nil, err	}	_, _, size, err := ReadBatchLine(rd)	if err != nil {		cancel()		return nil, 0, nil, err	}	b.gotSize = true	b.size = size	return rd, size, cancel, err} // Size returns the uncompressed size of the blobfunc (b *Blob) Size() int64 {	if b.gotSize {		return b.size	} 	wr, rd, cancel, err := b.repo.CatFileBatchCheck(b.repo.Ctx)	if err != nil {		log.Debug("error whilst reading size for %s in %s. Error: %v", b.ID.String(), b.repo.Path, err)		return 0	}	defer cancel()	_, err = wr.Write([]byte(b.ID.String() + "\n"))	if err != nil {		log.Debug("error whilst reading size for %s in %s. Error: %v", b.ID.String(), b.repo.Path, err)		return 0	}	_, _, b.size, err = ReadBatchLine(rd)	if err != nil {		log.Debug("error whilst reading size for %s in %s. Error: %v", b.ID.String(), b.repo.Path, err)		return 0	} 	b.gotSize = true 	return b.size} // DataAsync gets a ReadCloser for the contents of a blob without reading it all.// Calling the Close function on the result will discard all unread output.func (b *Blob) DataAsync() (io.ReadCloser, error) {	rd, size, cancel, err := b.newReader()	if err != nil {		return nil, err	} 	if size < 4096 {		bs, err := io.ReadAll(io.LimitReader(rd, size))		defer cancel()		if err != nil {			return nil, err		}		_, err = rd.Discard(1)		return io.NopCloser(bytes.NewReader(bs)), err	} 	return &blobReader{		rd:     rd,		n:      size,		cancel: cancel,	}, nil} type blobReader struct {	rd                *bufio.Reader	n                 int64 // number of bytes to read	additionalDiscard int64 // additional number of bytes to discard	cancel            func()} func (b *blobReader) Read(p []byte) (n int, err error) {	if b.n <= 0 {		return 0, io.EOF	}	if int64(len(p)) > b.n {		p = p[0:b.n]	}	n, err = b.rd.Read(p)	b.n -= int64(n)	return n, err} // Close implements io.Closerfunc (b *blobReader) Close() error {	if b.rd == nil {		return nil	} 	defer b.cancel() 	// discard the unread bytes, the truncated bytes and the trailing newline	if err := DiscardFull(b.rd, b.n+b.additionalDiscard+1); err != nil {		return err	} 	b.rd = nil 	return nil} // Name returns name of the tree entry this blob object was created from (or empty string)func (b *Blob) Name() string {	return b.name} // NewTruncatedReader return a blob-reader which silently truncates when the limit is reached (io.EOF will be returned)func (b *Blob) NewTruncatedReader(limit int64) (rc io.ReadCloser, fullSize int64, err error) {	r, fullSize, cancel, err := b.newReader()	if err != nil {		return nil, fullSize, err	} 	limit = min(limit, fullSize)	return &blobReader{		rd:                r,		n:                 limit,		additionalDiscard: fullSize - limit,		cancel:            cancel,	}, fullSize, nil} // GetBlobContent Gets the truncated content of the blob as raw textfunc (b *Blob) GetBlobContent(limit int64) (string, error) {	if limit <= 0 {		return "", nil	}	rc, fullSize, err := b.NewTruncatedReader(limit)	if err != nil {		return "", err	}	defer rc.Close() 	buf := make([]byte, min(fullSize, limit))	_, err = io.ReadFull(rc, buf)	return string(buf), err} type BlobTooLargeError struct {	Size, Limit int64} func (b BlobTooLargeError) Error() string {	return fmt.Sprintf("blob: content larger than limit (%d > %d)", b.Size, b.Limit)} // GetContentBase64 Reads the content of the blob and returns it as base64 encoded string.// Returns [BlobTooLargeError] if the (unencoded) content is larger than the limit.func (b *Blob) GetContentBase64(limit int64) (string, error) {	if b.Size() > limit {		return "", BlobTooLargeError{			Size:  b.Size(),			Limit: limit,		}	} 	rc, size, err := b.NewTruncatedReader(limit)	if err != nil {		return "", err	}	defer rc.Close() 	encoding := base64.StdEncoding	buf := bytes.NewBuffer(make([]byte, 0, encoding.EncodedLen(int(size)))) 	encoder := base64.NewEncoder(encoding, buf) 	if _, err := io.Copy(encoder, rc); err != nil {		return "", err	}	if err := encoder.Close(); err != nil {		return "", err	} 	return buf.String(), nil} // GuessContentType guesses the content type of the blob.func (b *Blob) GuessContentType() (typesniffer.SniffedType, error) {	r, err := b.DataAsync()	if err != nil {		return typesniffer.SniffedType{}, err	}	defer r.Close() 	return typesniffer.DetectContentTypeFromReader(r, b.Name())} // GetBlob finds the blob object in the repository.func (repo *Repository) GetBlob(idStr string) (*Blob, error) {	id, err := NewIDFromString(idStr)	if err != nil {		return nil, err	}	if id.IsZero() {		return nil, ErrNotExist{id.String(), ""}	}	return &Blob{		ID:   id,		repo: repo,	}, nil}