commit 53b6727af430ed942a9e624b0425fe4d624122db
Author: Catherine <whitequark@whitequark.org>
Date:   Fri Sep 5 01:26:37 2025 +0000

    Initial commit.

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..3af0ccb
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+/data
diff --git a/src/fetch.go b/src/fetch.go
new file mode 100644
index 0000000..6f852ce
--- /dev/null
+++ b/src/fetch.go
@@ -0,0 +1,121 @@
+package main
+
+import (
+	"errors"
+	"fmt"
+	"log"
+	"os"
+	"path/filepath"
+	"strings"
+
+	"github.com/go-git/go-billy/v6/osfs"
+	"github.com/go-git/go-git/v6"
+	"github.com/go-git/go-git/v6/plumbing"
+	"github.com/go-git/go-git/v6/storage/memory"
+)
+
+func splitHash(hash plumbing.Hash) string {
+	head := hash.String()
+	return filepath.Join(head[:2], head[2:])
+}
+
+func fetch(
+	dataDir string,
+	webroot string,
+	url string,
+	branch plumbing.ReferenceName,
+) (*plumbing.Hash, error) {
+	storer := memory.NewStorage()
+
+	repo, err := git.Clone(storer, nil, &git.CloneOptions{
+		URL:           url,
+		ReferenceName: branch,
+		SingleBranch:  true,
+		Depth:         1,
+		Tags:          git.NoTags,
+	})
+	if err != nil {
+		return nil, fmt.Errorf("git clone: %s", err)
+	}
+
+	ref, err := repo.Head()
+	if err != nil {
+		return nil, fmt.Errorf("git head: %s", err)
+	}
+	head := ref.Hash()
+
+	destDir := filepath.Join(dataDir, "tree", splitHash(head))
+	if _, err := os.Stat(destDir); errors.Is(err, os.ErrNotExist) {
+		// check out to a temporary directory to avoid TOCTTOU race on destDir
+		tempDir, err := os.MkdirTemp(dataDir, ".tree")
+		if err != nil {
+			return nil, fmt.Errorf("mkdir temp: %s", err)
+		}
+		defer os.RemoveAll(tempDir)
+
+		repo, err = git.Open(storer, osfs.New(tempDir))
+		if err != nil {
+			return nil, fmt.Errorf("git open: %s", err)
+		}
+
+		worktree, err := repo.Worktree()
+		if err != nil {
+			return nil, fmt.Errorf("git worktree: %s", err)
+		}
+
+		if err := worktree.Checkout(&git.CheckoutOptions{
+			Hash: head,
+		}); err != nil {
+			return nil, fmt.Errorf("git checkout: %s", err)
+		}
+
+		if err := os.MkdirAll(filepath.Dir(destDir), 0o755); err != nil {
+			return nil, fmt.Errorf("mkdir parent dest: %s", err)
+		}
+
+		// commit atomically; assume another fetch has won the race if directory exists
+		if err := os.Rename(tempDir, destDir); err != nil && !errors.Is(err, os.ErrExist) {
+			return nil, fmt.Errorf("rename dest: %s", err)
+		}
+	}
+
+	webLink := filepath.Join(dataDir, "www", webroot)
+	destDirRel, _ := filepath.Rel(filepath.Dir(webLink), destDir)
+
+	tempLink := filepath.Join(dataDir,
+		fmt.Sprintf(".link.%s.%s", strings.ReplaceAll(webroot, "/", ".."), head.String()))
+	if err := os.Symlink(destDirRel, tempLink); err != nil {
+		return nil, fmt.Errorf("symlink temp: %s", err)
+	}
+	defer os.Remove(tempLink)
+
+	if err := os.MkdirAll(filepath.Dir(webLink), 0o755); err != nil {
+		return nil, fmt.Errorf("mkdir parent web: %s", err)
+	}
+
+	// commit atomically; assume another fetch has won the race if symlink exists
+	// FIXME: might not have the same target
+	if err := os.Rename(tempLink, webLink); err != nil && !errors.Is(err, os.ErrExist) {
+		return nil, fmt.Errorf("rename web: %s", err)
+	}
+
+	return &head, nil
+}
+
+func Fetch(
+	dataDir string,
+	webroot string,
+	url string,
+	branch plumbing.ReferenceName,
+) error {
+	log.Println("fetch:", webroot, url, branch)
+
+	head, err := fetch(dataDir, webroot, url, branch)
+	if err != nil {
+		log.Println("fetch err:", fmt.Errorf("%s: %s", webroot, err))
+		return err
+	}
+
+	log.Println("fetch ok:", webroot, head)
+	return nil
+}
diff --git a/src/go.mod b/src/go.mod
new file mode 100644
index 0000000..cdbc6bf
--- /dev/null
+++ b/src/go.mod
@@ -0,0 +1,26 @@
+module whitequark.org/git-pages
+
+go 1.23.0
+
+toolchain go1.24.4
+
+require github.com/go-git/go-git/v6 v6.0.0-20250831162718-34f273445e00
+
+require (
+	dario.cat/mergo v1.0.1 // indirect
+	github.com/Microsoft/go-winio v0.6.2 // indirect
+	github.com/ProtonMail/go-crypto v1.3.0 // indirect
+	github.com/cloudflare/circl v1.6.1 // indirect
+	github.com/cyphar/filepath-securejoin v0.4.1 // indirect
+	github.com/emirpasic/gods v1.18.1 // indirect
+	github.com/go-git/gcfg/v2 v2.0.2 // indirect
+	github.com/go-git/go-billy/v6 v6.0.0-20250627091229-31e2a16eef30 // indirect
+	github.com/golang/groupcache v0.0.0-20241129210726-2c02b8208cf8 // indirect
+	github.com/kevinburke/ssh_config v1.4.0 // indirect
+	github.com/pjbgf/sha1cd v0.4.0 // indirect
+	github.com/sergi/go-diff v1.4.0 // indirect
+	golang.org/x/crypto v0.41.0 // indirect
+	golang.org/x/exp v0.0.0-20250531010427-b6e5de432a8b // indirect
+	golang.org/x/net v0.43.0 // indirect
+	golang.org/x/sys v0.35.0 // indirect
+)
diff --git a/src/go.sum b/src/go.sum
new file mode 100644
index 0000000..a1762c0
--- /dev/null
+++ b/src/go.sum
@@ -0,0 +1,47 @@
+dario.cat/mergo v1.0.1 h1:Ra4+bf83h2ztPIQYNP99R6m+Y7KfnARDfID+a+vLl4s=
+dario.cat/mergo v1.0.1/go.mod h1:uNxQE+84aUszobStD9th8a29P2fMDhsBdgRYvZOxGmk=
+github.com/Microsoft/go-winio v0.6.2 h1:F2VQgta7ecxGYO8k3ZZz3RS8fVIXVxONVUPlNERoyfY=
+github.com/Microsoft/go-winio v0.6.2/go.mod h1:yd8OoFMLzJbo9gZq8j5qaps8bJ9aShtEA8Ipt1oGCvU=
+github.com/ProtonMail/go-crypto v1.3.0 h1:ILq8+Sf5If5DCpHQp4PbZdS1J7HDFRXz/+xKBiRGFrw=
+github.com/ProtonMail/go-crypto v1.3.0/go.mod h1:9whxjD8Rbs29b4XWbB8irEcE8KHMqaR2e7GWU1R+/PE=
+github.com/cloudflare/circl v1.6.1 h1:zqIqSPIndyBh1bjLVVDHMPpVKqp8Su/V+6MeDzzQBQ0=
+github.com/cloudflare/circl v1.6.1/go.mod h1:uddAzsPgqdMAYatqJ0lsjX1oECcQLIlRpzZh3pJrofs=
+github.com/cyphar/filepath-securejoin v0.4.1 h1:JyxxyPEaktOD+GAnqIqTf9A8tHyAG22rowi7HkoSU1s=
+github.com/cyphar/filepath-securejoin v0.4.1/go.mod h1:Sdj7gXlvMcPZsbhwhQ33GguGLDGQL7h7bg04C/+u9jI=
+github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/emirpasic/gods v1.18.1 h1:FXtiHYKDGKCW2KzwZKx0iC0PQmdlorYgdFG9jPXJ1Bc=
+github.com/emirpasic/gods v1.18.1/go.mod h1:8tpGGwCnJ5H4r6BWwaV6OrWmMoPhUl5jm/FMNAnJvWQ=
+github.com/go-git/gcfg/v2 v2.0.2 h1:MY5SIIfTGGEMhdA7d7JePuVVxtKL7Hp+ApGDJAJ7dpo=
+github.com/go-git/gcfg/v2 v2.0.2/go.mod h1:/lv2NsxvhepuMrldsFilrgct6pxzpGdSRC13ydTLSLs=
+github.com/go-git/go-billy/v6 v6.0.0-20250627091229-31e2a16eef30 h1:4KqVJTL5eanN8Sgg3BV6f2/QzfZEFbCd+rTak1fGRRA=
+github.com/go-git/go-billy/v6 v6.0.0-20250627091229-31e2a16eef30/go.mod h1:snwvGrbywVFy2d6KJdQ132zapq4aLyzLMgpo79XdEfM=
+github.com/go-git/go-git/v6 v6.0.0-20250831162718-34f273445e00 h1:eW0gxk9rk3jv7mf4r+sKNLXNgex2LMReedRCRJewQhw=
+github.com/go-git/go-git/v6 v6.0.0-20250831162718-34f273445e00/go.mod h1:O7tkz+vcaOSOSRqAGC+MG6evNI8NsTmyH98ey4BTYwk=
+github.com/golang/groupcache v0.0.0-20241129210726-2c02b8208cf8 h1:f+oWsMOmNPc8JmEHVZIycC7hBoQxHH9pNKQORJNozsQ=
+github.com/golang/groupcache v0.0.0-20241129210726-2c02b8208cf8/go.mod h1:wcDNUvekVysuuOpQKo3191zZyTpiI6se1N1ULghS0sw=
+github.com/kevinburke/ssh_config v1.4.0 h1:6xxtP5bZ2E4NF5tuQulISpTO2z8XbtH8cg1PWkxoFkQ=
+github.com/kevinburke/ssh_config v1.4.0/go.mod h1:q2RIzfka+BXARoNexmF9gkxEX7DmvbW9P4hIVx2Kg4M=
+github.com/kr/pretty v0.1.0/go.mod h1:dAy3ld7l9f0ibDNOQOHHMYYIIbhfbHSm3C4ZsoJORNo=
+github.com/kr/pty v1.1.1/go.mod h1:pFQYn66WHrOpPYNljwOMqo10TkYh1fy3cYio2l3bCsQ=
+github.com/kr/text v0.1.0/go.mod h1:4Jbv+DJW3UT/LiOwJeYQe1efqtUx/iVham/4vfdArNI=
+github.com/pjbgf/sha1cd v0.4.0 h1:NXzbL1RvjTUi6kgYZCX3fPwwl27Q1LJndxtUDVfJGRY=
+github.com/pjbgf/sha1cd v0.4.0/go.mod h1:zQWigSxVmsHEZow5qaLtPYxpcKMMQpa09ixqBxuCS6A=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/sergi/go-diff v1.4.0 h1:n/SP9D5ad1fORl+llWyN+D6qoUETXNZARKjyY2/KVCw=
+github.com/sergi/go-diff v1.4.0/go.mod h1:A0bzQcvG0E7Rwjx0REVgAGH58e96+X0MeOfepqsbeW4=
+github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
+github.com/stretchr/testify v1.4.0/go.mod h1:j7eGeouHqKxXV5pUuKE4zz7dFj8WfuZ+81PSLYec5m4=
+golang.org/x/crypto v0.41.0 h1:WKYxWedPGCTVVl5+WHSSrOBT0O8lx32+zxmHxijgXp4=
+golang.org/x/crypto v0.41.0/go.mod h1:pO5AFd7FA68rFak7rOAGVuygIISepHftHnr8dr6+sUc=
+golang.org/x/exp v0.0.0-20250531010427-b6e5de432a8b h1:QoALfVG9rhQ/M7vYDScfPdWjGL9dlsVVM5VGh7aKoAA=
+golang.org/x/exp v0.0.0-20250531010427-b6e5de432a8b/go.mod h1:U6Lno4MTRCDY+Ba7aCcauB9T60gsv5s4ralQzP72ZoQ=
+golang.org/x/net v0.43.0 h1:lat02VYK2j4aLzMzecihNvTlJNQUq316m2Mr9rnM6YE=
+golang.org/x/net v0.43.0/go.mod h1:vhO1fvI4dGsIjh73sWfUVjj3N7CA9WkKJNQm2svM6Jg=
+golang.org/x/sys v0.35.0 h1:vz1N37gP5bs89s7He8XuIYXpyY0+QlsKmzipCbUtyxI=
+golang.org/x/sys v0.35.0/go.mod h1:BJP2sWEmIv4KK5OTEluFJCKSidICx8ciO85XgH3Ak8k=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/check.v1 v1.0.0-20190902080502-41f04d3bba15/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v2 v2.2.2/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
+gopkg.in/yaml.v2 v2.4.0/go.mod h1:RDklbk79AGWmwhnvt/jBztapEOGDOx6ZbXqjP6csGnQ=
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diff --git a/src/main.go b/src/main.go
new file mode 100644
index 0000000..752b85a
--- /dev/null
+++ b/src/main.go
@@ -0,0 +1,11 @@
+package main
+
+import (
+	"os"
+)
+
+func main() {
+	dataDir := os.Args[1]
+
+	Fetch(dataDir, "codeberg.page/index", "https://codeberg.org/Codeberg/pages-server/", "pages")
+}