1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
|
package main
import (
"bytes"
"compress/zlib"
"fmt"
"io"
"os"
)
func main() {
if len(os.Args) < 2 {
fmt.Fprintf(os.Stderr, "usage: mygit <command> [<args>...]\n")
os.Exit(1)
}
switch command := os.Args[1]; command {
case "init":
for _, dir := range []string{".git", ".git/objects", ".git/refs"} {
if err := os.MkdirAll(dir, 0755); err != nil {
fmt.Fprintf(os.Stderr, "Error creating directory: %s\n", err)
}
}
headFileContents := []byte("ref: refs/heads/main\n")
if err := os.WriteFile(".git/HEAD", headFileContents, 0644); err != nil {
fmt.Fprintf(os.Stderr, "Error writing file: %s\n", err)
}
fmt.Println("Initialized git directory")
case "cat-file":
object := os.Args[3]
filePath := fmt.Sprintf(".git/objects/%s/%s", object[:2], object[2:])
file, err := os.Open(filePath)
if err != nil {
fmt.Fprintf(os.Stderr, "Error opening file: %s\n", err)
os.Exit(1)
}
defer file.Close()
r, err := zlib.NewReader(file)
if err != nil {
fmt.Fprintf(os.Stderr, "Error creating zlib reader: %s\n", err)
os.Exit(1)
}
defer r.Close()
w, err := io.ReadAll(r)
if err != nil {
fmt.Fprintf(os.Stderr, "Error reading zlib data: %s\n", err)
os.Exit(1)
}
parts := bytes.Split(w, []byte("\x00"))
if len(parts) < 2 {
fmt.Fprintf(os.Stderr, "Invalid zlib data\n")
os.Exit(1)
}
fmt.Print(string(parts[1]))
default:
fmt.Fprintf(os.Stderr, "Unknown command %s\n", command)
os.Exit(1)
}
}
|
