chore(cmd): clean up commands (#9705)

Move infrastructure related commands to under `cmd/infra` and
development stuff to `cmd/dev`. The default build command builds the
regular user facing binaries: syncthing, stdiscosrv, and strelaysrv.

cmd/dev/stcompdirs/main.go

@@ -0,0 +1,164 @@
+// Copyright (C) 2014 The Syncthing Authors.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at https://mozilla.org/MPL/2.0/.
+
+package main
+
+import (
+	"crypto/sha256"
+	"errors"
+	"flag"
+	"fmt"
+	"io"
+	"log"
+	"os"
+	"path/filepath"
+
+	_ "github.com/syncthing/syncthing/lib/automaxprocs"
+)
+
+func main() {
+	flag.Parse()
+	log.Println(compareDirectories(flag.Args()...))
+}
+
+// Compare a number of directories. Returns nil if the contents are identical,
+// otherwise an error describing the first found difference.
+func compareDirectories(dirs ...string) error {
+	chans := make([]chan fileInfo, len(dirs))
+	for i := range chans {
+		chans[i] = make(chan fileInfo)
+	}
+	errcs := make([]chan error, len(dirs))
+	abort := make(chan struct{})
+
+	for i := range dirs {
+		errcs[i] = startWalker(dirs[i], chans[i], abort)
+	}
+
+	res := make([]fileInfo, len(dirs))
+	for {
+		numDone := 0
+		for i := range chans {
+			fi, ok := <-chans[i]
+			if !ok {
+				err, hasError := <-errcs[i]
+				if hasError {
+					close(abort)
+					return err
+				}
+				numDone++
+			}
+			res[i] = fi
+		}
+
+		for i := 1; i < len(res); i++ {
+			if res[i] != res[0] {
+				close(abort)
+				if res[i].name < res[0].name {
+					return fmt.Errorf("%s missing %v (present in %s)", dirs[0], res[i], dirs[i])
+				} else if res[i].name > res[0].name {
+					return fmt.Errorf("%s missing %v (present in %s)", dirs[i], res[0], dirs[0])
+				}
+				return fmt.Errorf("mismatch; %v (%s) != %v (%s)", res[i], dirs[i], res[0], dirs[0])
+			}
+		}
+
+		if numDone == len(dirs) {
+			return nil
+		}
+	}
+}
+
+type fileInfo struct {
+	name string
+	mode os.FileMode
+	mod  int64
+	hash [sha256.Size]byte
+}
+
+func (f fileInfo) String() string {
+	return fmt.Sprintf("%s %04o %d %x", f.name, f.mode, f.mod, f.hash)
+}
+
+func startWalker(dir string, res chan<- fileInfo, abort <-chan struct{}) chan error {
+	walker := func(path string, info os.FileInfo, err error) error {
+		if err != nil {
+			return err
+		}
+
+		rn, _ := filepath.Rel(dir, path)
+		if rn == "." {
+			return nil
+		}
+		if rn == ".stversions" || rn == ".stfolder" {
+			return filepath.SkipDir
+		}
+
+		var f fileInfo
+		if info.Mode()&os.ModeSymlink != 0 {
+			f = fileInfo{
+				name: rn,
+				mode: os.ModeSymlink,
+			}
+
+			tgt, err := os.Readlink(path)
+			if err != nil {
+				return err
+			}
+			f.hash = sha256.Sum256([]byte(tgt))
+		} else if info.IsDir() {
+			f = fileInfo{
+				name: rn,
+				mode: info.Mode(),
+				// hash and modtime zero for directories
+			}
+		} else {
+			f = fileInfo{
+				name: rn,
+				mode: info.Mode(),
+				mod:  info.ModTime().Unix(),
+			}
+			sum, err := sha256file(path)
+			if err != nil {
+				return err
+			}
+			f.hash = sum
+		}
+
+		select {
+		case res <- f:
+			return nil
+		case <-abort:
+			return errors.New("abort")
+		}
+	}
+
+	errc := make(chan error)
+	go func() {
+		err := filepath.Walk(dir, walker)
+		close(res)
+		if err != nil {
+			errc <- err
+		}
+		close(errc)
+	}()
+	return errc
+}
+
+func sha256file(fname string) (hash [sha256.Size]byte, err error) {
+	f, err := os.Open(fname)
+	if err != nil {
+		return
+	}
+	defer f.Close()
+
+	h := sha256.New()
+	io.Copy(h, f)
+	hb := h.Sum(nil)
+	copy(hash[:], hb)
+
+	return
+}