From 902bb1cc2a0a8644e160f303be1a2e0ad354bfd5 Mon Sep 17 00:00:00 2001
From: Luke Shumaker <lukeshu@lukeshu.com>
Date: Wed, 15 Nov 2017 15:38:05 -0500
Subject: initial commit

---
 filter.go | 103 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 103 insertions(+)
 create mode 100644 filter.go

(limited to 'filter.go')

diff --git a/filter.go b/filter.go
new file mode 100644
index 0000000..0c09963
--- /dev/null
+++ b/filter.go
@@ -0,0 +1,103 @@
+package main
+
+import (
+	"os"
+	"os/exec"
+	"bytes"
+)
+
+var prog [string]string
+
+func init() {
+	var err error
+	for _, p := range []string{"git", "makepkg"} {
+		prog[p], err = exec.LookPath("git")
+		if err != nil {
+			panic(err)
+		}
+	}
+}
+
+func pipeline(cmds ...*exec.Cmd) err error {
+	for i, cmd := range cmds[:len(cmds)-1] {
+		cmds[i+1].Stdin, err = cmd.StdoutPipe()
+		if err != nil {
+			return
+		}
+	}
+
+	stderr := make([]bytes.Buffer, len(cmds))
+	for i, cmd := range cmds {
+		cmd.Stderr = &stderr[i]
+		if err = cmd.Start(); err != nil {
+			break
+		}
+	}
+
+	for i, cmd := range cmds {
+		if cmd.Process == nil {
+			continue
+		}
+		if _err := cmd.Wait(); _err != nil {
+			if ee, ok := _err.(*exec.ExitError); ok {
+				ee.Stderr = stderr[i].Bytes()
+			}
+			if err != nil {
+				err = _err
+			}
+		}
+	}
+	return
+}
+
+func pkgbuild2srcinfo(pkgbuildId string) (string, error) {
+	cachefilename := "filter/pkgbuild2srcinfo/"+pkgbuildId
+	for {
+		b, err := ioutil.ReadFile(cachefilename)
+		if err == nil && len(bytes.TrimSpace(b)) == 40 {
+			return bytes.TrimSpace(b).String(), nil
+		}
+	
+		file, err := os.OpenFile("filter/tmp/PKGBUILD", os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0644)
+		if err != nil {
+			return "", err
+		}
+		err = pipeline(
+			&exec.Cmd{
+				Path: prog["git"], Args: ["git", "cat-file", "blob", pkgbuildId],
+				Stdout: file,
+			})
+		file.Close()
+		if err != nil {
+			return "", err
+		}
+
+
+		file, err = os.OpenFile(cachefilename, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0644)
+		err = pipeline(
+			&exec.Cmd{
+				Path: prog["makepkg"], Args: ["makepkg", "--printsrcinfo"],
+				Dir: "filter/tmp"
+			},
+			&exec.Cmd{
+				Path: prog["git"], Args: ["git", "hash-object", "-t", "blob", "-w", "--stdin", "--no-filters"],
+				Stdout: &buf,
+			})
+		file.Close()
+		if err != nil {
+			return "", err
+		}
+	}
+}
+
+
+
+func filter(fromPfix string, toPfix string) {
+	exec.Cmd{
+		Path: prog["git"], Args: ["git", "fast-export",
+			"--use-done-feature",
+			"--no-data",
+			"--", fromPfix + "/master"],
+	}
+	
+}
-- 
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