Moves files

internal/debug/debug.go

@@ -0,0 +1,202 @@
+// +build debug
+
+package debug
+
+import (
+	"fmt"
+	"log"
+	"os"
+	"path"
+	"path/filepath"
+	"restic/fs"
+	"runtime"
+	"strings"
+
+	"restic/errors"
+)
+
+var opts struct {
+	logger *log.Logger
+	funcs  map[string]bool
+	files  map[string]bool
+}
+
+// make sure that all the initialization happens before the init() functions
+// are called, cf https://golang.org/ref/spec#Package_initialization
+var _ = initDebug()
+
+func initDebug() bool {
+	initDebugLogger()
+	initDebugTags()
+
+	fmt.Fprintf(os.Stderr, "debug enabled\n")
+
+	return true
+}
+
+func initDebugLogger() {
+	debugfile := os.Getenv("DEBUG_LOG")
+	if debugfile == "" {
+		return
+	}
+
+	fmt.Fprintf(os.Stderr, "debug log file %v\n", debugfile)
+
+	f, err := fs.OpenFile(debugfile, os.O_WRONLY|os.O_APPEND, 0600)
+
+	if err == nil {
+		_, err = f.Seek(2, 0)
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "unable to seek to the end of %v: %v\n", debugfile, err)
+			os.Exit(3)
+		}
+	}
+
+	if err != nil && os.IsNotExist(errors.Cause(err)) {
+		f, err = fs.OpenFile(debugfile, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0600)
+	}
+
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "unable to open debug log file: %v\n", err)
+		os.Exit(2)
+	}
+
+	opts.logger = log.New(f, "", log.LstdFlags)
+}
+
+func parseFilter(envname string, pad func(string) string) map[string]bool {
+	filter := make(map[string]bool)
+
+	env := os.Getenv(envname)
+	if env == "" {
+		return filter
+	}
+
+	for _, fn := range strings.Split(env, ",") {
+		t := pad(strings.TrimSpace(fn))
+		val := true
+		if t[0] == '-' {
+			val = false
+			t = t[1:]
+		} else if t[0] == '+' {
+			val = true
+			t = t[1:]
+		}
+
+		// test pattern
+		_, err := path.Match(t, "")
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "error: invalid pattern %q: %v\n", t, err)
+			os.Exit(5)
+		}
+
+		filter[t] = val
+	}
+
+	return filter
+}
+
+func padFunc(s string) string {
+	if s == "all" {
+		return s
+	}
+
+	return s
+}
+
+func padFile(s string) string {
+	if s == "all" {
+		return s
+	}
+
+	if !strings.Contains(s, "/") {
+		s = "*/" + s
+	}
+
+	if !strings.Contains(s, ":") {
+		s = s + ":*"
+	}
+
+	return s
+}
+
+func initDebugTags() {
+	opts.funcs = parseFilter("DEBUG_FUNCS", padFunc)
+	opts.files = parseFilter("DEBUG_FILES", padFile)
+}
+
+// taken from https://github.com/VividCortex/trace
+func goroutineNum() int {
+	b := make([]byte, 20)
+	runtime.Stack(b, false)
+	var num int
+
+	fmt.Sscanf(string(b), "goroutine %d ", &num)
+	return num
+}
+
+// taken from https://github.com/VividCortex/trace
+func getPosition() (fn, dir, file string, line int) {
+	pc, file, line, ok := runtime.Caller(2)
+	if !ok {
+		return "", "", "", 0
+	}
+
+	dirname, filename := filepath.Base(filepath.Dir(file)), filepath.Base(file)
+
+	Func := runtime.FuncForPC(pc)
+
+	return path.Base(Func.Name()), dirname, filename, line
+}
+
+func checkFilter(filter map[string]bool, key string) bool {
+	// check if key is enabled directly
+	if v, ok := filter[key]; ok {
+		return v
+	}
+
+	// check for globbing
+	for k, v := range filter {
+		if m, _ := path.Match(k, key); m {
+			return v
+		}
+	}
+
+	// check if tag "all" is enabled
+	if v, ok := filter["all"]; ok && v {
+		return true
+	}
+
+	return false
+}
+
+// Log prints a message to the debug log (if debug is enabled).
+func Log(f string, args ...interface{}) {
+	fn, dir, file, line := getPosition()
+	goroutine := goroutineNum()
+
+	if len(f) == 0 || f[len(f)-1] != '\n' {
+		f += "\n"
+	}
+
+	pos := fmt.Sprintf("%s/%s:%d", dir, file, line)
+
+	formatString := fmt.Sprintf("%s\t%s\t%d\t%s", pos, fn, goroutine, f)
+
+	dbgprint := func() {
+		fmt.Fprintf(os.Stderr, formatString, args...)
+	}
+
+	if opts.logger != nil {
+		opts.logger.Printf(formatString, args...)
+	}
+
+	if checkFilter(opts.files, fmt.Sprintf("%s/%s:%d", dir, file, line)) {
+		dbgprint()
+		return
+	}
+
+	if checkFilter(opts.funcs, fn) {
+		dbgprint()
+	}
+}