Use "git show" instead of "git cat-file"

internal/git/blob.go

@@ -2,16 +2,12 @@ package git
 
 import (
 	"../helper"
-	"bufio"
 	"encoding/base64"
 	"fmt"
 	"io"
 	"net/http"
 )
 
-const blobLine = `blob
-`
-
 func SendGitBlob(w http.ResponseWriter, r *http.Request, repoPath string, blobId string) {
 	blobSpec, err := base64.URLEncoding.DecodeString(blobId)
 	if err != nil {
@@ -19,44 +15,24 @@ func SendGitBlob(w http.ResponseWriter, r *http.Request, repoPath string, blobId
 		return
 	}
 
-	catFileCmd := gitCommand("", "git", "--git-dir="+repoPath, "cat-file", "--batch=%(objecttype)")
-	catFileStdin, err := catFileCmd.StdinPipe()
-	if err != nil {
-		helper.Fail500(w, fmt.Errorf("SendGitBlob: git cat-file stdin: %v", err))
-		return
-	}
-
-	catFileStdout, err := catFileCmd.StdoutPipe()
+	gitShowCmd := gitCommand("", "git", "--git-dir="+repoPath, "show", string(blobSpec))
+	stdout, err := gitShowCmd.StdoutPipe()
 	if err != nil {
-		helper.Fail500(w, fmt.Errorf("SendGitBlob: git cat-file stdout: %v", err))
-		return
-	}
-
-	if err := catFileCmd.Start(); err != nil {
-		helper.Fail500(w, fmt.Errorf("SendGitBlob: start %v: %v", catFileCmd, err))
-		return
-	}
-	defer cleanUpProcessGroup(catFileCmd)
-	if _, err := fmt.Fprintf(catFileStdin, "%s\n", blobSpec); err != nil {
-		helper.Fail500(w, fmt.Errorf("SendGitBlob: send command to git cat-file: %v", err))
-		return
-	}
-	if err := catFileStdin.Close(); err != nil {
-		helper.Fail500(w, fmt.Errorf("SendGitBlob: close git cat-file stdin: %v", err))
+		helper.Fail500(w, fmt.Errorf("SendGitBlob: git show stdout: %v", err))
 		return
 	}
-	out := bufio.NewReader(catFileStdout)
-	if response, err := out.ReadString('\n'); err != nil || response != blobLine {
-		helper.Fail500(w, fmt.Errorf("SendGitBlob: git cat-file returned %q, error: %v", response, err))
+	if err := gitShowCmd.Start(); err != nil {
+		helper.Fail500(w, fmt.Errorf("SendGitBlob: start %v: %v", gitShowCmd, err))
 		return
 	}
+	defer cleanUpProcessGroup(gitShowCmd)
 
-	if _, err := io.Copy(w, catFileStdout); err != nil {
-		helper.LogError(fmt.Errorf("SendGitBlob: copy git cat-file stdout: %v", err))
+	if _, err := io.Copy(w, stdout); err != nil {
+		helper.LogError(fmt.Errorf("SendGitBlob: copy git show stdout: %v", err))
 		return
 	}
-	if err := catFileCmd.Wait(); err != nil {
-		helper.LogError(fmt.Errorf("SendGitBlob: wait for git cat-file: %v", err))
+	if err := gitShowCmd.Wait(); err != nil {
+		helper.LogError(fmt.Errorf("SendGitBlob: wait for git show: %v", err))
 		return
 	}
 }