gitea/modules/git/blob.go

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// 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"
"fmt"
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"io"
"io/ioutil"
"os"
"os/exec"
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)
// 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())
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}
return stdout, nil
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}
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// DataPipeline gets content of blob and write the result or error to stdout or stderr
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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
}