From: Marvin Stenger <marvin.stenger94@gmail.com>
Date: Mon, 25 Sep 2017 13:47:44 +0000 (+0200)
Subject: all: prefer strings.LastIndexByte over strings.LastIndex
X-Git-Tag: go1.10beta1~971
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=d2826d3e068f096f4b5371175afb7e5d8c4aa73c;p=gostls13.git

all: prefer strings.LastIndexByte over strings.LastIndex

strings.LastIndexByte was introduced in go1.5 and it can be used
effectively wherever the second argument to strings.LastIndex is
exactly one byte long.

This avoids generating unnecessary string symbols and saves
a few calls to strings.LastIndex.

Change-Id: I7b5679d616197b055cffe6882a8675d24a98b574
Reviewed-on: https://go-review.googlesource.com/66372
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
---

diff --git a/src/archive/tar/writer.go b/src/archive/tar/writer.go
index 0ae48b8b23..5e183cb2bb 100644
--- a/src/archive/tar/writer.go
+++ b/src/archive/tar/writer.go
@@ -376,7 +376,7 @@ func splitUSTARPath(name string) (prefix, suffix string, ok bool) {
 		length--
 	}
 
-	i := strings.LastIndex(name[:length], "/")
+	i := strings.LastIndexByte(name[:length], '/')
 	nlen := len(name) - i - 1 // nlen is length of suffix
 	plen := i                 // plen is length of prefix
 	if i <= 0 || nlen > nameSize || nlen == 0 || plen > prefixSize {
diff --git a/src/cmd/doc/main.go b/src/cmd/doc/main.go
index 09f551a45d..78ea038e61 100644
--- a/src/cmd/doc/main.go
+++ b/src/cmd/doc/main.go
@@ -205,7 +205,7 @@ func parseArgs(args []string) (pkg *build.Package, path, symbol string, more boo
 	}
 	// If it has a slash, it must be a package path but there is a symbol.
 	// It's the last package path we care about.
-	slash := strings.LastIndex(arg, "/")
+	slash := strings.LastIndexByte(arg, '/')
 	// There may be periods in the package path before or after the slash
 	// and between a symbol and method.
 	// Split the string at various periods to see what we find.
diff --git a/src/cmd/fix/fix.go b/src/cmd/fix/fix.go
index cdc3c839d3..f12d1c7fe0 100644
--- a/src/cmd/fix/fix.go
+++ b/src/cmd/fix/fix.go
@@ -719,7 +719,7 @@ func usesImport(f *ast.File, path string) (used bool) {
 	case "<nil>":
 		// If the package name is not explicitly specified,
 		// make an educated guess. This is not guaranteed to be correct.
-		lastSlash := strings.LastIndex(path, "/")
+		lastSlash := strings.LastIndexByte(path, '/')
 		if lastSlash == -1 {
 			name = path
 		} else {
diff --git a/src/cmd/vet/print.go b/src/cmd/vet/print.go
index 67a96ed2c4..f64e449f6d 100644
--- a/src/cmd/vet/print.go
+++ b/src/cmd/vet/print.go
@@ -38,7 +38,7 @@ func initPrintFlags() {
 
 		// Backwards compatibility: skip optional first argument
 		// index after the colon.
-		if colon := strings.LastIndex(name, ":"); colon > 0 {
+		if colon := strings.LastIndexByte(name, ':'); colon > 0 {
 			name = name[:colon]
 		}
 
diff --git a/src/crypto/tls/handshake_client.go b/src/crypto/tls/handshake_client.go
index f8db66279f..38d01bf068 100644
--- a/src/crypto/tls/handshake_client.go
+++ b/src/crypto/tls/handshake_client.go
@@ -848,7 +848,7 @@ func hostnameInSNI(name string) string {
 	if len(host) > 0 && host[0] == '[' && host[len(host)-1] == ']' {
 		host = host[1 : len(host)-1]
 	}
-	if i := strings.LastIndex(host, "%"); i > 0 {
+	if i := strings.LastIndexByte(host, '%'); i > 0 {
 		host = host[:i]
 	}
 	if net.ParseIP(host) != nil {
diff --git a/src/crypto/tls/tls.go b/src/crypto/tls/tls.go
index 615d1e5576..1c91daeb1c 100644
--- a/src/crypto/tls/tls.go
+++ b/src/crypto/tls/tls.go
@@ -122,7 +122,7 @@ func DialWithDialer(dialer *net.Dialer, network, addr string, config *Config) (*
 		return nil, err
 	}
 
-	colonPos := strings.LastIndex(addr, ":")
+	colonPos := strings.LastIndexByte(addr, ':')
 	if colonPos == -1 {
 		colonPos = len(addr)
 	}
diff --git a/src/debug/gosym/symtab.go b/src/debug/gosym/symtab.go
index b81f872801..eab255a359 100644
--- a/src/debug/gosym/symtab.go
+++ b/src/debug/gosym/symtab.go
@@ -40,7 +40,7 @@ func (s *Sym) Static() bool { return s.Type >= 'a' }
 // PackageName returns the package part of the symbol name,
 // or the empty string if there is none.
 func (s *Sym) PackageName() string {
-	pathend := strings.LastIndex(s.Name, "/")
+	pathend := strings.LastIndexByte(s.Name, '/')
 	if pathend < 0 {
 		pathend = 0
 	}
@@ -54,12 +54,12 @@ func (s *Sym) PackageName() string {
 // ReceiverName returns the receiver type name of this symbol,
 // or the empty string if there is none.
 func (s *Sym) ReceiverName() string {
-	pathend := strings.LastIndex(s.Name, "/")
+	pathend := strings.LastIndexByte(s.Name, '/')
 	if pathend < 0 {
 		pathend = 0
 	}
 	l := strings.IndexByte(s.Name[pathend:], '.')
-	r := strings.LastIndex(s.Name[pathend:], ".")
+	r := strings.LastIndexByte(s.Name[pathend:], '.')
 	if l == -1 || r == -1 || l == r {
 		return ""
 	}
@@ -68,7 +68,7 @@ func (s *Sym) ReceiverName() string {
 
 // BaseName returns the symbol name without the package or receiver name.
 func (s *Sym) BaseName() string {
-	if i := strings.LastIndex(s.Name, "."); i != -1 {
+	if i := strings.LastIndexByte(s.Name, '.'); i != -1 {
 		return s.Name[i+1:]
 	}
 	return s.Name
diff --git a/src/encoding/xml/marshal.go b/src/encoding/xml/marshal.go
index 42133a75ab..773f0f2862 100644
--- a/src/encoding/xml/marshal.go
+++ b/src/encoding/xml/marshal.go
@@ -333,7 +333,7 @@ func (p *printer) createAttrPrefix(url string) string {
 	// Pick a name. We try to use the final element of the path
 	// but fall back to _.
 	prefix := strings.TrimRight(url, "/")
-	if i := strings.LastIndex(prefix, "/"); i >= 0 {
+	if i := strings.LastIndexByte(prefix, '/'); i >= 0 {
 		prefix = prefix[i+1:]
 	}
 	if prefix == "" || !isName([]byte(prefix)) || strings.Contains(prefix, ":") {
diff --git a/src/go/build/build.go b/src/go/build/build.go
index 9822affa8a..c449ad95e8 100644
--- a/src/go/build/build.go
+++ b/src/go/build/build.go
@@ -465,7 +465,7 @@ func (e *MultiplePackageError) Error() string {
 }
 
 func nameExt(name string) string {
-	i := strings.LastIndex(name, ".")
+	i := strings.LastIndexByte(name, '.')
 	if i < 0 {
 		return ""
 	}
@@ -610,7 +610,7 @@ func (ctxt *Context) Import(path string, srcDir string, mode ImportMode) (*Packa
 						}
 						tried.vendor = append(tried.vendor, dir)
 					}
-					i := strings.LastIndex(sub, "/")
+					i := strings.LastIndexByte(sub, '/')
 					if i < 0 {
 						break
 					}
@@ -1064,7 +1064,7 @@ func (ctxt *Context) matchFile(dir, name string, allTags map[string]bool, binary
 		return
 	}
 
-	i := strings.LastIndex(name, ".")
+	i := strings.LastIndexByte(name, '.')
 	if i < 0 {
 		i = len(name)
 	}
diff --git a/src/go/doc/testdata/testing.go b/src/go/doc/testdata/testing.go
index 52810f7a56..066e4a43db 100644
--- a/src/go/doc/testdata/testing.go
+++ b/src/go/doc/testdata/testing.go
@@ -93,7 +93,7 @@ func decorate(s string, addFileLine bool) string {
 		_, file, line, ok := runtime.Caller(3) // decorate + log + public function.
 		if ok {
 			// Truncate file name at last file name separator.
-			if index := strings.LastIndex(file, "/"); index >= 0 {
+			if index := strings.LastIndexByte(file, '/'); index >= 0 {
 				file = file[index+1:]
 			} else if index = strings.LastIndex(file, "\\"); index >= 0 {
 				file = file[index+1:]
diff --git a/src/go/printer/printer.go b/src/go/printer/printer.go
index 4f4beadcab..6a954e21fe 100644
--- a/src/go/printer/printer.go
+++ b/src/go/printer/printer.go
@@ -624,7 +624,7 @@ func (p *printer) writeComment(comment *ast.Comment) {
 	if strings.HasPrefix(text, linePrefix) && (!pos.IsValid() || pos.Column == 1) {
 		// possibly a line directive
 		ldir := strings.TrimSpace(text[len(linePrefix):])
-		if i := strings.LastIndex(ldir, ":"); i >= 0 {
+		if i := strings.LastIndexByte(ldir, ':'); i >= 0 {
 			if line, err := strconv.Atoi(ldir[i+1:]); err == nil && line > 0 {
 				// The line directive we are about to print changed
 				// the Filename and Line number used for subsequent
diff --git a/src/go/types/resolver.go b/src/go/types/resolver.go
index ba75a0dc23..253f8a0334 100644
--- a/src/go/types/resolver.go
+++ b/src/go/types/resolver.go
@@ -172,7 +172,7 @@ func (check *Checker) importPackage(pos token.Pos, path, dir string) *Package {
 				if i := len(name); i > 0 && name[i-1] == '/' {
 					name = name[:i-1]
 				}
-				if i := strings.LastIndex(name, "/"); i >= 0 {
+				if i := strings.LastIndexByte(name, '/'); i >= 0 {
 					name = name[i+1:]
 				}
 				imp = NewPackage(path, name)
@@ -516,7 +516,7 @@ func (check *Checker) unusedImports() {
 
 // pkgName returns the package name (last element) of an import path.
 func pkgName(path string) string {
-	if i := strings.LastIndex(path, "/"); i >= 0 {
+	if i := strings.LastIndexByte(path, '/'); i >= 0 {
 		path = path[i+1:]
 	}
 	return path
diff --git a/src/internal/trace/parser.go b/src/internal/trace/parser.go
index a774bf14c9..1033d5222b 100644
--- a/src/internal/trace/parser.go
+++ b/src/internal/trace/parser.go
@@ -812,7 +812,7 @@ func symbolize(events []*Event, bin string) error {
 		f := &Frame{PC: pc}
 		f.Fn = fn[:len(fn)-1]
 		f.File = file[:len(file)-1]
-		if colon := strings.LastIndex(f.File, ":"); colon != -1 {
+		if colon := strings.LastIndexByte(f.File, ':'); colon != -1 {
 			ln, err := strconv.Atoi(f.File[colon+1:])
 			if err == nil {
 				f.File = f.File[:colon]
diff --git a/src/net/http/cookiejar/jar.go b/src/net/http/cookiejar/jar.go
index ef8c35bf0a..f147eceb18 100644
--- a/src/net/http/cookiejar/jar.go
+++ b/src/net/http/cookiejar/jar.go
@@ -330,7 +330,7 @@ func jarKey(host string, psl PublicSuffixList) string {
 
 	var i int
 	if psl == nil {
-		i = strings.LastIndex(host, ".")
+		i = strings.LastIndexByte(host, '.')
 		if i <= 0 {
 			return host
 		}
@@ -349,7 +349,7 @@ func jarKey(host string, psl PublicSuffixList) string {
 		// here on, so it is okay if psl.PublicSuffix("www.buggy.psl")
 		// returns "com" as the jar key is generated from host.
 	}
-	prevDot := strings.LastIndex(host[:i-1], ".")
+	prevDot := strings.LastIndexByte(host[:i-1], '.')
 	return host[prevDot+1:]
 }
 
@@ -365,7 +365,7 @@ func defaultPath(path string) string {
 		return "/" // Path is empty or malformed.
 	}
 
-	i := strings.LastIndex(path, "/") // Path starts with "/", so i != -1.
+	i := strings.LastIndexByte(path, '/') // Path starts with "/", so i != -1.
 	if i == 0 {
 		return "/" // Path has the form "/abc".
 	}
diff --git a/src/net/http/cookiejar/jar_test.go b/src/net/http/cookiejar/jar_test.go
index 47fb1abdaa..ed4baae4c6 100644
--- a/src/net/http/cookiejar/jar_test.go
+++ b/src/net/http/cookiejar/jar_test.go
@@ -37,7 +37,7 @@ func (testPSL) PublicSuffix(d string) string {
 	if d == "www2.buggy.psl" {
 		return "com"
 	}
-	return d[strings.LastIndex(d, ".")+1:]
+	return d[strings.LastIndexByte(d, '.')+1:]
 }
 
 // newTestJar creates an empty Jar with testPSL as the public suffix list.
diff --git a/src/net/http/http.go b/src/net/http/http.go
index b95ca89f40..7d5b74092e 100644
--- a/src/net/http/http.go
+++ b/src/net/http/http.go
@@ -35,7 +35,7 @@ func (k *contextKey) String() string { return "net/http context value " + k.name
 
 // Given a string of the form "host", "host:port", or "[ipv6::address]:port",
 // return true if the string includes a port.
-func hasPort(s string) bool { return strings.LastIndex(s, ":") > strings.LastIndex(s, "]") }
+func hasPort(s string) bool { return strings.LastIndexByte(s, ':') > strings.LastIndexByte(s, ']') }
 
 // removeEmptyPort strips the empty port in ":port" to ""
 // as mandated by RFC 3986 Section 6.2.3.
diff --git a/src/net/http/request.go b/src/net/http/request.go
index b7fcf806ba..e384517668 100644
--- a/src/net/http/request.go
+++ b/src/net/http/request.go
@@ -688,11 +688,11 @@ func removeZone(host string) string {
 	if !strings.HasPrefix(host, "[") {
 		return host
 	}
-	i := strings.LastIndex(host, "]")
+	i := strings.LastIndexByte(host, ']')
 	if i < 0 {
 		return host
 	}
-	j := strings.LastIndex(host[:i], "%")
+	j := strings.LastIndexByte(host[:i], '%')
 	if j < 0 {
 		return host
 	}
diff --git a/src/net/http/transport.go b/src/net/http/transport.go
index 5f2ace7b4b..034d016cb3 100644
--- a/src/net/http/transport.go
+++ b/src/net/http/transport.go
@@ -1236,7 +1236,7 @@ func useProxy(addr string) bool {
 
 	addr = strings.ToLower(strings.TrimSpace(addr))
 	if hasPort(addr) {
-		addr = addr[:strings.LastIndex(addr, ":")]
+		addr = addr[:strings.LastIndexByte(addr, ':')]
 	}
 
 	for _, p := range strings.Split(noProxy, ",") {
@@ -1245,7 +1245,7 @@ func useProxy(addr string) bool {
 			continue
 		}
 		if hasPort(p) {
-			p = p[:strings.LastIndex(p, ":")]
+			p = p[:strings.LastIndexByte(p, ':')]
 		}
 		if addr == p {
 			return false
@@ -1317,7 +1317,7 @@ func (cm *connectMethod) addr() string {
 func (cm *connectMethod) tlsHost() string {
 	h := cm.targetAddr
 	if hasPort(h) {
-		h = h[:strings.LastIndex(h, ":")]
+		h = h[:strings.LastIndexByte(h, ':')]
 	}
 	return h
 }
diff --git a/src/net/mail/message.go b/src/net/mail/message.go
index e080e017da..9c29e812c0 100644
--- a/src/net/mail/message.go
+++ b/src/net/mail/message.go
@@ -178,7 +178,7 @@ func (p *AddressParser) ParseList(list string) ([]*Address, error) {
 // the name will be rendered according to RFC 2047.
 func (a *Address) String() string {
 	// Format address local@domain
-	at := strings.LastIndex(a.Address, "@")
+	at := strings.LastIndexByte(a.Address, '@')
 	var local, domain string
 	if at < 0 {
 		// This is a malformed address ("@" is required in addr-spec);
diff --git a/src/net/rpc/server.go b/src/net/rpc/server.go
index 29aae7ee7f..0499f4abe2 100644
--- a/src/net/rpc/server.go
+++ b/src/net/rpc/server.go
@@ -592,7 +592,7 @@ func (server *Server) readRequestHeader(codec ServerCodec) (svc *service, mtype
 	// we can still recover and move on to the next request.
 	keepReading = true
 
-	dot := strings.LastIndex(req.ServiceMethod, ".")
+	dot := strings.LastIndexByte(req.ServiceMethod, '.')
 	if dot < 0 {
 		err = errors.New("rpc: service/method request ill-formed: " + req.ServiceMethod)
 		return
diff --git a/src/net/url/url.go b/src/net/url/url.go
index 02d446e4a2..a317d096f2 100644
--- a/src/net/url/url.go
+++ b/src/net/url/url.go
@@ -532,7 +532,7 @@ func parse(rawurl string, viaRequest bool) (*URL, error) {
 }
 
 func parseAuthority(authority string) (user *Userinfo, host string, err error) {
-	i := strings.LastIndex(authority, "@")
+	i := strings.LastIndexByte(authority, '@')
 	if i < 0 {
 		host, err = parseHost(authority)
 	} else {
@@ -569,7 +569,7 @@ func parseHost(host string) (string, error) {
 	if strings.HasPrefix(host, "[") {
 		// Parse an IP-Literal in RFC 3986 and RFC 6874.
 		// E.g., "[fe80::1]", "[fe80::1%25en0]", "[fe80::1]:80".
-		i := strings.LastIndex(host, "]")
+		i := strings.LastIndexByte(host, ']')
 		if i < 0 {
 			return "", errors.New("missing ']' in host")
 		}
@@ -885,7 +885,7 @@ func resolvePath(base, ref string) string {
 	if ref == "" {
 		full = base
 	} else if ref[0] != '/' {
-		i := strings.LastIndex(base, "/")
+		i := strings.LastIndexByte(base, '/')
 		full = base[:i+1] + ref
 	} else {
 		full = ref
diff --git a/src/os/exec/lp_windows.go b/src/os/exec/lp_windows.go
index 793d4d98b3..4e1ffb0014 100644
--- a/src/os/exec/lp_windows.go
+++ b/src/os/exec/lp_windows.go
@@ -26,7 +26,7 @@ func chkStat(file string) error {
 }
 
 func hasExt(file string) bool {
-	i := strings.LastIndex(file, ".")
+	i := strings.LastIndexByte(file, '.')
 	if i < 0 {
 		return false
 	}
diff --git a/src/path/path.go b/src/path/path.go
index 5c905110a1..074cfff67a 100644
--- a/src/path/path.go
+++ b/src/path/path.go
@@ -145,7 +145,7 @@ func Clean(path string) string {
 // file set to path.
 // The returned values have the property that path = dir+file.
 func Split(path string) (dir, file string) {
-	i := strings.LastIndex(path, "/")
+	i := strings.LastIndexByte(path, '/')
 	return path[:i+1], path[i+1:]
 }
 
@@ -187,7 +187,7 @@ func Base(path string) string {
 		path = path[0 : len(path)-1]
 	}
 	// Find the last element
-	if i := strings.LastIndex(path, "/"); i >= 0 {
+	if i := strings.LastIndexByte(path, '/'); i >= 0 {
 		path = path[i+1:]
 	}
 	// If empty now, it had only slashes.
diff --git a/src/testing/testing.go b/src/testing/testing.go
index a170cd0fd9..d5c045f253 100644
--- a/src/testing/testing.go
+++ b/src/testing/testing.go
@@ -360,7 +360,7 @@ func (c *common) decorate(s string) string {
 	_, file, line, ok := runtime.Caller(skip)
 	if ok {
 		// Truncate file name at last file name separator.
-		if index := strings.LastIndex(file, "/"); index >= 0 {
+		if index := strings.LastIndexByte(file, '/'); index >= 0 {
 			file = file[index+1:]
 		} else if index = strings.LastIndex(file, "\\"); index >= 0 {
 			file = file[index+1:]
diff --git a/src/time/mono_test.go b/src/time/mono_test.go
index 8778ab78a0..cc24db07f1 100644
--- a/src/time/mono_test.go
+++ b/src/time/mono_test.go
@@ -253,7 +253,7 @@ func TestMonotonicString(t *testing.T) {
 		t1 := Now()
 		SetMono(&t1, tt.mono)
 		s := t1.String()
-		got := s[strings.LastIndex(s, " ")+1:]
+		got := s[strings.LastIndexByte(s, ' ')+1:]
 		if got != tt.want {
 			t.Errorf("with mono=%d: got %q; want %q", tt.mono, got, tt.want)
 		}