Output-less target as a dependency

[goredo.git] / dep.go

diff --git a/dep.go b/dep.go
index e6663e65fb7afaa64dac6f435a6b633d70ff9625..d7c874a95ea4d845592611a8e85377e0722b6af3 100644 (file)
--- a/dep.go
+++ b/dep.go
@@ -1,6 +1,6 @@
 /*
 goredo -- redo implementation on pure Go
-Copyright (C) 2020 Sergey Matveev <stargrave@stargrave.org>
+Copyright (C) 2020-2021 Sergey Matveev <stargrave@stargrave.org>
 
 This program is free software: you can redistribute it and/or modify
 it under the terms of the GNU General Public License as published by
@@ -27,13 +27,15 @@ import (
        "io"
        "os"
        "path"
-       "strings"
-       "syscall"
+       "path/filepath"
 
        "go.cypherpunks.ru/recfile"
-       "golang.org/x/crypto/blake2b"
+       "golang.org/x/sys/unix"
+       "lukechampine.com/blake3"
 )
 
+var DirPrefix string
+
 func recfileWrite(fdDep *os.File, fields ...recfile.Field) error {
        w := recfile.NewWriter(fdDep)
        if _, err := w.RecordStart(); err != nil {
@@ -74,21 +76,17 @@ func stamp(fdDep, src *os.File) error {
 }
 
 func fileCtime(fd *os.File) (string, error) {
-       fi, err := fd.Stat()
-       if err != nil {
+       var stat unix.Stat_t
+       if err := unix.Fstat(int(fd.Fd()), &stat); err != nil {
                return "", err
        }
-       stat := fi.Sys().(*syscall.Stat_t)
-       sec, nsec := stat.Ctimespec.Unix()
+       sec, nsec := stat.Ctim.Unix()
        return fmt.Sprintf("%d.%d", sec, nsec), nil
 }
 
 func fileHash(fd *os.File) (string, error) {
-       h, err := blake2b.New256(nil)
-       if err != nil {
-               panic(err)
-       }
-       if _, err = io.Copy(h, bufio.NewReader(fd)); err != nil {
+       h := blake3.New(32, nil)
+       if _, err := io.Copy(h, bufio.NewReader(fd)); err != nil {
                return "", err
        }
        return hex.EncodeToString(h.Sum(nil)), nil
@@ -101,6 +99,13 @@ func writeDep(fdDep *os.File, cwd, tgt string) error {
                return err
        }
        defer fd.Close()
+       fi, err := fd.Stat()
+       if err != nil {
+               return err
+       }
+       if fi.IsDir() {
+               return nil
+       }
        ts, err := fileCtime(fd)
        if err != nil {
                return err
@@ -118,25 +123,34 @@ func writeDep(fdDep *os.File, cwd, tgt string) error {
        )
 }
 
-func writeDeps(fdDep *os.File, tgts []string) error {
+func writeDeps(fdDep *os.File, tgts []string) (err error) {
        if fdDep == nil {
                trace(CDebug, "no opened fdDep: %s", tgts)
                return nil
        }
-       ups := []string{}
-       upLevels := strings.Count(os.Getenv(EnvDirPrefix), "/")
-       for i := 0; i < upLevels; i++ {
-               ups = append(ups, "..")
-       }
-       up := path.Join(ups...)
        for _, tgt := range tgts {
-               if _, err := os.Stat(tgt); err == nil {
-                       if err = writeDep(fdDep, Cwd, path.Join(up, tgt)); err != nil {
-                               return err
-                       }
+               tgtAbs, err := filepath.Abs(tgt)
+               if err != nil {
+                       panic(err)
+               }
+               tgtDir := path.Join(Cwd, DirPrefix)
+               tgtRel, err := filepath.Rel(tgtDir, tgtAbs)
+               if err != nil {
+                       panic(err)
+               }
+               if _, errStat := os.Stat(tgt); errStat == nil {
+                       err = writeDep(fdDep, tgtDir, tgtRel)
+               } else {
+                       trace(CDebug, "ifchange: %s <- %s (unexisting)", fdDep.Name(), tgtRel)
+                       err = recfileWrite(
+                               fdDep,
+                               recfile.Field{Name: "Type", Value: DepTypeIfchange},
+                               recfile.Field{Name: "Target", Value: tgtRel},
+                               recfile.Field{Name: "Ctime", Value: "0.0"},
+                       )
                }
        }
-       return nil
+       return
 }
 
 type DepInfo struct {