forgejo-federation/modules/git/blob.go

103 lines
2.4 KiB
Go

// Copyright 2015 The Gogs Authors. All rights reserved.
// Use of this source code is governed by a MIT-style
// license that can be found in the LICENSE file.
package git
import (
"bytes"
"encoding/base64"
"fmt"
"io"
"io/ioutil"
"os"
"os/exec"
)
// Blob represents a Git object.
type Blob struct {
repo *Repository
*TreeEntry
}
// Data gets content of blob all at once and wrap it as io.Reader.
// This can be very slow and memory consuming for huge content.
func (b *Blob) Data() (io.Reader, error) {
stdout := new(bytes.Buffer)
stderr := new(bytes.Buffer)
// Preallocate memory to save ~50% memory usage on big files.
stdout.Grow(int(b.Size() + 2048))
if err := b.DataPipeline(stdout, stderr); err != nil {
return nil, concatenateError(err, stderr.String())
}
return stdout, nil
}
// DataPipeline gets content of blob and write the result or error to stdout or stderr
func (b *Blob) DataPipeline(stdout, stderr io.Writer) error {
return NewCommand("show", b.ID.String()).RunInDirPipeline(b.repo.Path, stdout, stderr)
}
type cmdReadCloser struct {
cmd *exec.Cmd
stdout io.Reader
}
func (c cmdReadCloser) Read(p []byte) (int, error) {
return c.stdout.Read(p)
}
func (c cmdReadCloser) Close() error {
io.Copy(ioutil.Discard, c.stdout)
return c.cmd.Wait()
}
// 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) {
cmd := exec.Command("git", "show", b.ID.String())
cmd.Dir = b.repo.Path
cmd.Stderr = os.Stderr
stdout, err := cmd.StdoutPipe()
if err != nil {
return nil, fmt.Errorf("StdoutPipe: %v", err)
}
if err = cmd.Start(); err != nil {
return nil, fmt.Errorf("Start: %v", err)
}
return cmdReadCloser{stdout: stdout, cmd: cmd}, nil
}
// 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 := ioutil.ReadAll(pr)
if err != nil {
return "", err
}
return string(out), nil
}