embed: simplify the code

Use stringslite and bytealg to simplify the code and to remove redundent
helper functions.

Change-Id: I665a8313d9b91201b147b255290058f162cf0894
GitHub-Last-Rev: e9e3bebdb477c301ec96e2b7425c20e6792d9765
GitHub-Pull-Request: golang/go#67515
Reviewed-on: https://go-review.googlesource.com/c/go/+/586715
Reviewed-by: Ian Lance Taylor <iant@google.com>
Auto-Submit: Ian Lance Taylor <iant@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Carlos Amedee <carlos@golang.org>

diff --git a/src/embed/embed.go b/src/embed/embed.go
index b7bb16099e56a1944adc88b17dda8acf54571f4d..f6c0ef9b97516090366bb8ab5230ab3a9584deed 100644 (file)
--- a/src/embed/embed.go
+++ b/src/embed/embed.go
@@ -130,6 +130,8 @@ package embed
 
 import (
        "errors"
+       "internal/bytealg"
+       "internal/stringslite"
        "io"
        "io/fs"
        "time"
@@ -185,29 +187,14 @@ type FS struct {
 // comment in the FS struct above. isDir reports whether the
 // final trailing slash was present, indicating that name is a directory.
 func split(name string) (dir, elem string, isDir bool) {
-       if name[len(name)-1] == '/' {
-               isDir = true
-               name = name[:len(name)-1]
-       }
-       i := len(name) - 1
-       for i >= 0 && name[i] != '/' {
-               i--
-       }
+       name, isDir = stringslite.CutSuffix(name, "/")
+       i := bytealg.LastIndexByteString(name, '/')
        if i < 0 {
                return ".", name, isDir
        }
        return name[:i], name[i+1:], isDir
 }
 
-// trimSlash trims a trailing slash from name, if present,
-// returning the possibly shortened name.
-func trimSlash(name string) string {
-       if len(name) > 0 && name[len(name)-1] == '/' {
-               return name[:len(name)-1]
-       }
-       return name
-}
-
 var (
        _ fs.ReadDirFS  = FS{}
        _ fs.ReadFileFS = FS{}
@@ -274,7 +261,7 @@ func (f FS) lookup(name string) *file {
                idir, ielem, _ := split(files[i].name)
                return idir > dir || idir == dir && ielem >= elem
        })
-       if i < len(files) && trimSlash(files[i].name) == name {
+       if i < len(files) && stringslite.TrimSuffix(files[i].name, "/") == name {
                return &files[i]
        }
        return nil