135 lines
3.1 KiB
Go
135 lines
3.1 KiB
Go
// Copyright (C) 2024 Umorpha Systems
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// SPDX-License-Identifier: AGPL-3.0-or-later
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package gitcache
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import (
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"errors"
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"os"
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"os/exec"
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"path/filepath"
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"sync"
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"time"
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"io"
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"fmt"
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)
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const tsDir = "x-gitcache-ts"
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type Cache struct {
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Dir string
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MinPeriod time.Duration
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initOnce sync.Once
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initErr error
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}
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// "ll" stands for "low level" /////////////////////////////////////////////////
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func (cache *Cache) llInit(stderr io.Writer) error {
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fmt.Fprintf(stderr, "[gitcache] Initializing cache...\n")
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cmd := exec.Command("git", "init", "--bare", cache.Dir)
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cmd.Stderr = stderr
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if err := cmd.Run(); err != nil {
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return err
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}
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if err := os.Mkdir(filepath.Join(cache.Dir, tsDir), 0o777); err != nil && !errors.Is(err, os.ErrExist) {
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return err
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}
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return nil
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}
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func (cache *Cache) llFetch(stderr io.Writer, namespace, url string) error {
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fmt.Fprintf(stderr, "[gitcache] Fetching %q...\n", url)
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cmd := exec.Command("git",
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"fetch",
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"--no-write-fetch-head",
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"--no-recurse-submodules",
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"--no-tags",
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"--prune",
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"--",
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url, "*:refs/namespaces/"+namespace+"/*")
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cmd.Dir = cache.Dir
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cmd.Stderr = stderr
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return cmd.Run()
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}
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////////////////////////////////////////////////////////////////////////////////
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func (cache *Cache) init(stderr io.Writer) error {
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cache.initOnce.Do(func() {
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cache.initErr = cache.llInit(stderr)
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})
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return cache.initErr
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}
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func (cache *Cache) Fetch(stderr io.Writer, url string) error {
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if err := cache.init(stderr); err != nil {
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return err
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}
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id := url2id(url)
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tsFile := filepath.Join(cache.Dir, tsDir, id)
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if cache.MinPeriod != 0 {
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ts, err := mtime(tsFile)
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if err == nil && ts.Add(cache.MinPeriod).After(time.Now()) {
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return nil
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}
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}
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if err := cache.llFetch(stderr, id, url); err != nil {
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return err
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}
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return touch(tsFile)
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}
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func (cache *Cache) Clone(stderr io.Writer, url, dir string, flags ...string) error {
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if err := cache.Fetch(stderr, url); err != nil {
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return err
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}
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cacheDir, err := filepath.Abs(cache.Dir)
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if err != nil {
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return err
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}
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cacheURL := "ext::git --namespace " + url2id(url) + " %s " + cacheDir
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fmt.Fprintf(stderr, "[gitcache] Cloning %q to %q...\n", url, dir)
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cmd := exec.Command("git", append(append([]string{
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"-c", "protocol.ext.allow=user",
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"-c", "url." + cacheURL + ".insteadOf=" + url,
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"clone",
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}, flags...), "--", url, dir)...)
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cmd.Stderr = stderr
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if err := cmd.Run(); err != nil {
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return err
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}
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return nil
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}
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func (cache *Cache) RevParse(stderr io.Writer, url, rev string) (string, error) {
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if err := cache.Fetch(stderr, url); err != nil {
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return "", err
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}
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// `git rev-parse` doesn't obey `--namespace`, so we have to
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// create a temporary clone to do this :(
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tmpdir, err := os.MkdirTemp("", "gitcache-revparse")
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if err != nil {
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return "", err
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}
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defer os.RemoveAll(tmpdir)
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gitdir := filepath.Join(tmpdir, "clone.git")
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if err := cache.Clone(stderr, url, gitdir, "--mirror"); err != nil {
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return "", err
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}
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cmd := exec.Command("git", "rev-parse", "--verify", rev)
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cmd.Dir = gitdir
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cmd.Stderr = stderr
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out, err := cmd.Output()
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if err != nil {
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return "", err
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}
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return string(out[:len(out)-1]), nil
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}
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