Monorepo for Tangled
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Go
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import ( "bufio" "context" "crypto/sha256" "fmt" "io" "iter" "os/exec" "path" "strconv" "strings" "time"
"github.com/dgraph-io/ristretto" "github.com/go-git/go-git/v5/plumbing" "tangled.org/core/sets" "tangled.org/core/types")
var ( commitCache *ristretto.Cache)
func init() { cache, _ := ristretto.NewCache(&ristretto.Config{ NumCounters: 1e7, MaxCost: 1 << 30, BufferItems: 64, TtlTickerDurationInSec: 120, }) commitCache = cache}
// processReader wraps a reader and ensures the associated process is cleaned uptype processReader struct { io.Reader cmd *exec.Cmd stdout io.ReadCloser}
func (pr *processReader) Close() error { if err := pr.stdout.Close(); err != nil { return err } return pr.cmd.Wait()}
func (g *GitRepo) streamingGitLog(ctx context.Context, extraArgs ...string) (io.ReadCloser, error) { args := []string{} args = append(args, "log") args = append(args, g.h.String()) args = append(args, extraArgs...)
cmd := exec.CommandContext(ctx, "git", args...) cmd.Dir = g.path
stdout, err := cmd.StdoutPipe() if err != nil { return nil, err }
if err := cmd.Start(); err != nil { return nil, err }
return &processReader{ Reader: stdout, cmd: cmd, stdout: stdout, }, nil}
type commit struct { hash plumbing.Hash when time.Time files sets.Set[string] message string}
func newCommit() commit { return commit{ files: sets.New[string](), }}
type lastCommitDir struct { dir string entries []string}
func (l lastCommitDir) children() iter.Seq[string] { return func(yield func(string) bool) { for _, child := range l.entries { if !yield(path.Join(l.dir, child)) { return } } }}
func cacheKey(g *GitRepo, path string) string { sep := byte(':') hash := sha256.Sum256(fmt.Append([]byte{}, g.path, sep, g.h.String(), sep, path)) return fmt.Sprintf("%x", hash)}
func (g *GitRepo) lastCommitDirIn(ctx context.Context, parent lastCommitDir, timeout time.Duration) (map[string]commit, error) { ctx, cancel := context.WithTimeout(ctx, timeout) defer cancel() return g.lastCommitDir(ctx, parent)}
func (g *GitRepo) lastCommitDir(ctx context.Context, parent lastCommitDir) (map[string]commit, error) { filesToDo := sets.Collect(parent.children()) filesDone := make(map[string]commit)
for p := range filesToDo.All() { cacheKey := cacheKey(g, p) if cached, ok := commitCache.Get(cacheKey); ok { filesDone[p] = cached.(commit) filesToDo.Remove(p) } else { filesToDo.Insert(p) } }
if filesToDo.IsEmpty() { return filesDone, nil }
ctx, cancel := context.WithCancel(ctx) defer cancel()
pathSpec := "." if parent.dir != "" { pathSpec = parent.dir } if filesToDo.Len() == 1 { // this is an optimization for the scenario where we want to calculate // the last commit for just one path, we can directly set the pathspec to that path for s := range filesToDo.All() { pathSpec = s } }
output, err := g.streamingGitLog(ctx, "--pretty=format:%H,%ad,%s", "--date=unix", "--name-only", "--", pathSpec) if err != nil { return nil, err } defer output.Close() // Ensure the git process is properly cleaned up
reader := bufio.NewReader(output) current := newCommit() for { line, err := reader.ReadString('\n') if err != nil && err != io.EOF { return nil, err } line = strings.TrimSpace(line)
if line == "" { if !current.hash.IsZero() { // we have a fully parsed commit for f := range current.files.All() { if filesToDo.Contains(f) { filesDone[f] = current filesToDo.Remove(f) commitCache.Set(cacheKey(g, f), current, 0) } }
if filesToDo.IsEmpty() { break } current = newCommit() } } else if current.hash.IsZero() { parts := strings.SplitN(line, ",", 3) if len(parts) == 3 { current.hash = plumbing.NewHash(parts[0]) epochTime, _ := strconv.ParseInt(parts[1], 10, 64) current.when = time.Unix(epochTime, 0) current.message = parts[2] } } else { // all ancestors along this path should also be included file := path.Clean(line) current.files.Insert(file) for _, a := range ancestors(file) { current.files.Insert(a) } }
if err == io.EOF { break } }
return filesDone, nil}
// LastCommitFile returns the last commit information for a specific file pathfunc (g *GitRepo) LastCommitFile(ctx context.Context, filePath string) (*types.LastCommitInfo, error) { parent, child := path.Split(filePath) parent = path.Clean(parent) if parent == "." { parent = "" }
lastCommitDir := lastCommitDir{ dir: parent, entries: []string{child}, }
times, err := g.lastCommitDirIn(ctx, lastCommitDir, 2*time.Second) if err != nil { return nil, fmt.Errorf("calculate commit time: %w", err) }
// extract the only element of the map, the commit info of the current path var commitInfo *commit for _, c := range times { commitInfo = &c }
if commitInfo == nil { return nil, fmt.Errorf("no commit found for path: %s", filePath) }
return &types.LastCommitInfo{ Hash: commitInfo.hash, Message: commitInfo.message, When: commitInfo.when, }, nil}
func ancestors(p string) []string { var ancestors []string
for { p = path.Dir(p) if p == "." || p == "/" { break } ancestors = append(ancestors, p) } return ancestors}