1 files changed, 228 insertions, 0 deletions
diff --git a/modules/git/blob.go b/modules/git/blob.go
new file mode 100644
index 0000000..2f02693
--- /dev/null
+++ b/modules/git/blob.go
@@ -0,0 +1,228 @@
+// 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"
+	"io"
+
+	"code.gitea.io/gitea/modules/log"
+	"code.gitea.io/gitea/modules/typesniffer"
+	"code.gitea.io/gitea/modules/util"
+)
+
+// Blob represents a Git object.
+type Blob struct {
+	ID ObjectID
+
+	gotSize bool
+	size    int64
+	name    string
+	repo    *Repository
+}
+
+// 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) {
+	wr, rd, cancel, err := b.repo.CatFileBatch(b.repo.Ctx)
+	if err != nil {
+		return nil, err
+	}
+
+	_, err = wr.Write([]byte(b.ID.String() + "\n"))
+	if err != nil {
+		cancel()
+		return nil, err
+	}
+	_, _, size, err := ReadBatchLine(rd)
+	if err != nil {
+		cancel()
+		return nil, err
+	}
+	b.gotSize = true
+	b.size = size
+
+	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
+}
+
+// Size returns the uncompressed size of the blob
+func (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
+}
+
+type blobReader struct {
+	rd     *bufio.Reader
+	n      int64
+	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.Closer
+func (b *blobReader) Close() error {
+	if b.rd == nil {
+		return nil
+	}
+
+	defer b.cancel()
+
+	if err := DiscardFull(b.rd, b.n+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
+}
+
+// GetBlobContent Gets the limited content of the blob as raw text
+func (b *Blob) GetBlobContent(limit int64) (string, error) {
+	if limit <= 0 {
+		return "", nil
+	}
+	dataRc, err := b.DataAsync()
+	if err != nil {
+		return "", err
+	}
+	defer dataRc.Close()
+	buf, err := util.ReadWithLimit(dataRc, int(limit))
+	return string(buf), err
+}
+
+// GetBlobLineCount gets line count of the blob
+func (b *Blob) GetBlobLineCount() (int, error) {
+	reader, err := b.DataAsync()
+	if err != nil {
+		return 0, err
+	}
+	defer reader.Close()
+	buf := make([]byte, 32*1024)
+	count := 1
+	lineSep := []byte{'\n'}
+
+	c, err := reader.Read(buf)
+	if c == 0 && err == io.EOF {
+		return 0, nil
+	}
+	for {
+		count += bytes.Count(buf[:c], lineSep)
+		switch {
+		case err == io.EOF:
+			return count, nil
+		case err != nil:
+			return count, err
+		}
+		c, err = reader.Read(buf)
+	}
+}
+
+// GetBlobContentBase64 Reads the content of the blob with a base64 encode and returns the encoded string
+func (b *Blob) GetBlobContentBase64() (string, error) {
+	dataRc, err := b.DataAsync()
+	if err != nil {
+		return "", err
+	}
+	defer dataRc.Close()
+
+	pr, pw := io.Pipe()
+	encoder := base64.NewEncoder(base64.StdEncoding, pw)
+
+	go func() {
+		_, err := io.Copy(encoder, dataRc)
+		_ = encoder.Close()
+
+		if err != nil {
+			_ = pw.CloseWithError(err)
+		} else {
+			_ = pw.Close()
+		}
+	}()
+
+	out, err := io.ReadAll(pr)
+	if err != nil {
+		return "", err
+	}
+	return string(out), 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)
+}
+
+// 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
+}