From 976122914b1eee6f050e2ae25096377efbf0a3da Mon Sep 17 00:00:00 2001
From: Laria Carolin Chabowski <laria@laria.me>
Date: Thu, 27 Jun 2019 22:43:01 +0200
Subject: Replace brittle git2go dependency

---
 git/git.go         | 77 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 projects/readme.go | 36 +++++--------------------
 2 files changed, 84 insertions(+), 29 deletions(-)
 create mode 100644 git/git.go

diff --git a/git/git.go b/git/git.go
new file mode 100644
index 0000000..c22de51
--- /dev/null
+++ b/git/git.go
@@ -0,0 +1,77 @@
+package git
+
+import (
+	"bufio"
+	"bytes"
+	"errors"
+	"os/exec"
+	"regexp"
+)
+
+type TreeEntry struct {
+	Mode, Type, Object, Name string
+}
+
+var reTreeEntry = regexp.MustCompile("^(\\d+) (\\w+) ([0-9a-f]+)\t(.*)$")
+
+var (
+	ErrUnexpectedLsTreeOutput = errors.New("Unexpected git ls-tree output")
+)
+
+func splitZero(data []byte, atEOF bool) (advance int, token []byte, err error) {
+	if atEOF && len(data) == 0 {
+		return 0, nil, nil
+	}
+	if i := bytes.IndexByte(data, '\x00'); i >= 0 {
+		return i + 1, data[0:i], nil
+	}
+	if atEOF {
+		return len(data), data, nil
+	}
+
+	return 0, nil, nil
+}
+
+func ReadTree(repoPath string, ref string) ([]TreeEntry, error) {
+	cmd := exec.Command("git", "-C", repoPath, "ls-tree", "--full-tree", "-z", ref)
+	var out bytes.Buffer
+	cmd.Stdout = &out
+
+	if err := cmd.Run(); err != nil {
+		return nil, err
+	}
+
+	scanner := bufio.NewScanner(&out)
+	scanner.Split(splitZero)
+
+	entries := []TreeEntry{}
+	for scanner.Scan() {
+		line := scanner.Bytes()
+		m := reTreeEntry.FindSubmatch(line)
+		if m == nil {
+			return nil, ErrUnexpectedLsTreeOutput
+		}
+
+		entries = append(entries, TreeEntry{
+			Mode:   string(m[1]),
+			Type:   string(m[2]),
+			Object: string(m[3]),
+			Name:   string(m[4]),
+		})
+	}
+
+	return entries, nil
+}
+
+func ReadBlob(repoPath string, ref string) ([]byte, error) {
+	var buf bytes.Buffer
+
+	cmd := exec.Command("git", "-C", repoPath, "cat-file", "blob", ref)
+	cmd.Stdout = &buf
+
+	if err := cmd.Run(); err != nil {
+		return nil, err
+	}
+
+	return buf.Bytes(), nil
+}
diff --git a/projects/readme.go b/projects/readme.go
index c57b831..85fa71f 100644
--- a/projects/readme.go
+++ b/projects/readme.go
@@ -2,7 +2,7 @@ package projects
 
 import (
 	"bytes"
-	"github.com/libgit2/git2go"
+	"code.laria.me/code.laria.me/git"
 	"html"
 	"html/template"
 	"io"
@@ -46,39 +46,17 @@ func formatMarkdown(raw []byte) template.HTML {
 }
 
 func gitReadme(gitpath string) (raw []byte, name string, err error) {
-	repo, err := git.OpenRepository(gitpath)
+	ents, err := git.ReadTree(gitpath, "master")
 	if err != nil {
 		return raw, name, err
 	}
 
-	master_tree_obj, err := repo.RevparseSingle("master:") // Root tree of commit at top of master
-	if err != nil {
-		return raw, name, err
-	}
-
-	master_tree, err := master_tree_obj.AsTree()
-	if err != nil {
-		return raw, name, err
-	}
-
-	var inner_err error = nil
-	err = master_tree.Walk(func(_ string, entry *git.TreeEntry) int {
-		if !(strings.HasPrefix(strings.ToLower(entry.Name), "readme") && entry.Type == git.ObjectBlob) {
-			return 1
-		}
-
-		name = entry.Name
-		blob, err := repo.LookupBlob(entry.Id)
-		if err == nil {
-			raw = blob.Contents()
-		} else {
-			inner_err = err
+	for _, ent := range ents {
+		if ent.Type == "blob" && strings.HasPrefix(strings.ToLower(ent.Name), "readme") {
+			name = ent.Name
+			raw, err = git.ReadBlob(gitpath, ent.Object)
+			return
 		}
-		return 1
-	})
-
-	if err == nil && inner_err != nil {
-		err = inner_err
 	}
 
 	return
-- 
cgit v1.2.3-54-g00ecf