cmd/go: split out cmd/go/internal/str

This is one CL in a long sequence of changes to break up the
go command from one package into a plausible group of packages.

This sequence is concerned only with moving code, not changing
or cleaning up code. There will still be more cleanup after this sequence.

The entire sequence will be submitted together: it is not a goal
for the tree to build at every step.

For #18653.

Change-Id: I63f578f5ac99c707b599ac5659293c46b275567d
Reviewed-on: https://go-review.googlesource.com/36190
Reviewed-by: David Crawshaw <[email protected]>

Author: rsc

src/cmd/go/build.go

@@ -7,6 +7,7 @@ package main
 import (
 	"bufio"
 	"bytes"
+	"cmd/go/internal/str"
 	"container/heap"
 	"debug/elf"
 	"errors"
@@ -2091,7 +2092,7 @@ func (b *builder) run(dir string, desc string, env []string, cmdargs ...interfac
 	out, err := b.runOut(dir, desc, env, cmdargs...)
 	if len(out) > 0 {
 		if desc == "" {
-			desc = b.fmtcmd(dir, "%s", strings.Join(stringList(cmdargs...), " "))
+			desc = b.fmtcmd(dir, "%s", strings.Join(str.StringList(cmdargs...), " "))
 		}
 		b.showOutput(dir, desc, b.processOutput(out))
 		if err != nil {
@@ -2121,7 +2122,7 @@ func (b *builder) processOutput(out []byte) string {
 // runOut runs the command given by cmdline in the directory dir.
 // It returns the command output and any errors that occurred.
 func (b *builder) runOut(dir string, desc string, env []string, cmdargs ...interface{}) ([]byte, error) {
-	cmdline := stringList(cmdargs...)
+	cmdline := str.StringList(cmdargs...)
 	if buildN || buildX {
 		var envcmdline string
 		for i := range env {
@@ -2450,7 +2451,7 @@ func toolVerify(b *builder, p *Package, newTool string, ofile string, args []int
 		return err
 	}
 	if !bytes.Equal(data1, data2) {
-		return fmt.Errorf("%s and %s produced different output files:\n%s\n%s", filepath.Base(args[1].(string)), newTool, strings.Join(stringList(args...), " "), strings.Join(stringList(newArgs...), " "))
+		return fmt.Errorf("%s and %s produced different output files:\n%s\n%s", filepath.Base(args[1].(string)), newTool, strings.Join(str.StringList(args...), " "), strings.Join(str.StringList(newArgs...), " "))
 	}
 	os.Remove(ofile + ".new")
 	return nil
@@ -2477,7 +2478,7 @@ func (gcToolchain) pack(b *builder, p *Package, objDir, afile string, ofiles []s
 	}
 
 	if buildN || buildX {
-		cmdline := stringList("pack", "r", absAfile, absOfiles)
+		cmdline := str.StringList("pack", "r", absAfile, absOfiles)
 		b.showcmd(p.Dir, "%s # internal", joinUnambiguously(cmdline))
 	}
 	if buildN {
@@ -2692,7 +2693,7 @@ func (tools gccgoToolchain) gc(b *builder, p *Package, archive, obj string, asmh
 	if p.localPrefix != "" {
 		gcargs = append(gcargs, "-fgo-relative-import-path="+p.localPrefix)
 	}
-	args := stringList(tools.compiler(), importArgs, "-c", gcargs, "-o", ofile, buildGccgoflags)
+	args := str.StringList(tools.compiler(), importArgs, "-c", gcargs, "-o", ofile, buildGccgoflags)
 	for _, f := range gofiles {
 		args = append(args, mkAbs(p.Dir, f))
 	}
@@ -2913,7 +2914,7 @@ func (tools gccgoToolchain) link(b *builder, root *action, out string, allaction
 		ldflags = append(ldflags, root.p.CgoLDFLAGS...)
 	}
 
-	ldflags = stringList("-Wl,-(", ldflags, "-Wl,-)")
+	ldflags = str.StringList("-Wl,-(", ldflags, "-Wl,-)")
 
 	for _, shlib := range shlibs {
 		ldflags = append(
@@ -3244,11 +3245,11 @@ func envList(key, def string) []string {
 func (b *builder) cflags(p *Package) (cppflags, cflags, cxxflags, fflags, ldflags []string) {
 	defaults := "-g -O2"
 
-	cppflags = stringList(envList("CGO_CPPFLAGS", ""), p.CgoCPPFLAGS)
-	cflags = stringList(envList("CGO_CFLAGS", defaults), p.CgoCFLAGS)
-	cxxflags = stringList(envList("CGO_CXXFLAGS", defaults), p.CgoCXXFLAGS)
-	fflags = stringList(envList("CGO_FFLAGS", defaults), p.CgoFFLAGS)
-	ldflags = stringList(envList("CGO_LDFLAGS", defaults), p.CgoLDFLAGS)
+	cppflags = str.StringList(envList("CGO_CPPFLAGS", ""), p.CgoCPPFLAGS)
+	cflags = str.StringList(envList("CGO_CFLAGS", defaults), p.CgoCFLAGS)
+	cxxflags = str.StringList(envList("CGO_CXXFLAGS", defaults), p.CgoCXXFLAGS)
+	fflags = str.StringList(envList("CGO_FFLAGS", defaults), p.CgoFFLAGS)
+	ldflags = str.StringList(envList("CGO_LDFLAGS", defaults), p.CgoLDFLAGS)
 	return
 }
 
@@ -3354,7 +3355,7 @@ func (b *builder) cgo(a *action, cgoExe, obj string, pcCFLAGS, pcLDFLAGS, cgofil
 	outGo = append(outGo, gofiles...)
 
 	// gcc
-	cflags := stringList(cgoCPPFLAGS, cgoCFLAGS)
+	cflags := str.StringList(cgoCPPFLAGS, cgoCFLAGS)
 	for _, cfile := range cfiles {
 		ofile := obj + cfile[:len(cfile)-1] + "o"
 		if err := b.gcc(p, ofile, cflags, obj+cfile); err != nil {
@@ -3372,7 +3373,7 @@ func (b *builder) cgo(a *action, cgoExe, obj string, pcCFLAGS, pcLDFLAGS, cgofil
 		outObj = append(outObj, ofile)
 	}
 
-	cxxflags := stringList(cgoCPPFLAGS, cgoCXXFLAGS)
+	cxxflags := str.StringList(cgoCPPFLAGS, cgoCXXFLAGS)
 	for _, file := range gxxfiles {
 		// Append .o to the file, just in case the pkg has file.c and file.cpp
 		ofile := obj + cgoRe.ReplaceAllString(filepath.Base(file), "_") + ".o"
@@ -3391,7 +3392,7 @@ func (b *builder) cgo(a *action, cgoExe, obj string, pcCFLAGS, pcLDFLAGS, cgofil
 		outObj = append(outObj, ofile)
 	}
 
-	fflags := stringList(cgoCPPFLAGS, cgoFFLAGS)
+	fflags := str.StringList(cgoCPPFLAGS, cgoFFLAGS)
 	for _, file := range ffiles {
 		// Append .o to the file, just in case the pkg has file.c and file.f
 		ofile := obj + cgoRe.ReplaceAllString(filepath.Base(file), "_") + ".o"
@@ -3440,7 +3441,7 @@ func (b *builder) dynimport(p *Package, obj, importGo, cgoExe string, cflags, cg
 		return err
 	}
 
-	linkobj := stringList(ofile, outObj, p.SysoFiles)
+	linkobj := str.StringList(ofile, outObj, p.SysoFiles)
 	dynobj := obj + "_cgo_.o"
 
 	// we need to use -pie for Linux/ARM to get accurate imported sym
@@ -3672,9 +3673,9 @@ func (b *builder) swigOne(p *Package, file, obj string, pcCFLAGS []string, cxx b
 	cgoCPPFLAGS, cgoCFLAGS, cgoCXXFLAGS, _, _ := b.cflags(p)
 	var cflags []string
 	if cxx {
-		cflags = stringList(cgoCPPFLAGS, pcCFLAGS, cgoCXXFLAGS)
+		cflags = str.StringList(cgoCPPFLAGS, pcCFLAGS, cgoCXXFLAGS)
 	} else {
-		cflags = stringList(cgoCPPFLAGS, pcCFLAGS, cgoCFLAGS)
+		cflags = str.StringList(cgoCPPFLAGS, pcCFLAGS, cgoCFLAGS)
 	}
 
 	n := 5 // length of ".swig"

src/cmd/go/fix.go

@@ -4,6 +4,8 @@
 
 package main
 
+import "cmd/go/internal/str"
+
 var cmdFix = &Command{
 	Run:       runFix,
 	UsageLine: "fix [packages]",
@@ -25,6 +27,6 @@ func runFix(cmd *Command, args []string) {
 		// Use pkg.gofiles instead of pkg.Dir so that
 		// the command only applies to this package,
 		// not to packages in subdirectories.
-		run(stringList(buildToolExec, tool("fix"), relPaths(pkg.allgofiles)))
+		run(str.StringList(buildToolExec, tool("fix"), relPaths(pkg.allgofiles)))
 	}
 }

src/cmd/go/fmt.go

@@ -5,6 +5,7 @@
 package main
 
 import (
+	"cmd/go/internal/str"
 	"os"
 	"path/filepath"
 )
@@ -39,7 +40,7 @@ func runFmt(cmd *Command, args []string) {
 		// Use pkg.gofiles instead of pkg.Dir so that
 		// the command only applies to this package,
 		// not to packages in subdirectories.
-		run(stringList(gofmt, "-l", "-w", relPaths(pkg.allgofiles)))
+		run(str.StringList(gofmt, "-l", "-w", relPaths(pkg.allgofiles)))
 	}
 }
 

src/cmd/go/get.go

@@ -5,6 +5,7 @@
 package main
 
 import (
+	"cmd/go/internal/str"
 	"fmt"
 	"go/build"
 	"os"
@@ -302,7 +303,7 @@ func download(arg string, parent *Package, stk *importStack, mode int) {
 	// due to wildcard expansion.
 	for _, p := range pkgs {
 		if *getFix {
-			run(buildToolExec, stringList(tool("fix"), relPaths(p.allgofiles)))
+			run(buildToolExec, str.StringList(tool("fix"), relPaths(p.allgofiles)))
 
 			// The imports might have changed, so reload again.
 			p = reloadPackage(arg, stk)
@@ -324,7 +325,7 @@ func download(arg string, parent *Package, stk *importStack, mode int) {
 			// Process test dependencies when -t is specified.
 			// (But don't get test dependencies for test dependencies:
 			// we always pass mode 0 to the recursive calls below.)
-			imports = stringList(imports, p.TestImports, p.XTestImports)
+			imports = str.StringList(imports, p.TestImports, p.XTestImports)
 		}
 		for i, path := range imports {
 			if path == "C" {

src/cmd/go/internal/str/str.go

@@ -0,0 +1,97 @@
+// Copyright 2017 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package str provides string manipulation utilities.
+package str
+
+import (
+	"bytes"
+	"fmt"
+	"unicode"
+	"unicode/utf8"
+)
+
+// StringList flattens its arguments into a single []string.
+// Each argument in args must have type string or []string.
+func StringList(args ...interface{}) []string {
+	var x []string
+	for _, arg := range args {
+		switch arg := arg.(type) {
+		case []string:
+			x = append(x, arg...)
+		case string:
+			x = append(x, arg)
+		default:
+			panic("stringList: invalid argument of type " + fmt.Sprintf("%T", arg))
+		}
+	}
+	return x
+}
+
+// toFold returns a string with the property that
+//	strings.EqualFold(s, t) iff toFold(s) == toFold(t)
+// This lets us test a large set of strings for fold-equivalent
+// duplicates without making a quadratic number of calls
+// to EqualFold. Note that strings.ToUpper and strings.ToLower
+// do not have the desired property in some corner cases.
+func toFold(s string) string {
+	// Fast path: all ASCII, no upper case.
+	// Most paths look like this already.
+	for i := 0; i < len(s); i++ {
+		c := s[i]
+		if c >= utf8.RuneSelf || 'A' <= c && c <= 'Z' {
+			goto Slow
+		}
+	}
+	return s
+
+Slow:
+	var buf bytes.Buffer
+	for _, r := range s {
+		// SimpleFold(x) cycles to the next equivalent rune > x
+		// or wraps around to smaller values. Iterate until it wraps,
+		// and we've found the minimum value.
+		for {
+			r0 := r
+			r = unicode.SimpleFold(r0)
+			if r <= r0 {
+				break
+			}
+		}
+		// Exception to allow fast path above: A-Z => a-z
+		if 'A' <= r && r <= 'Z' {
+			r += 'a' - 'A'
+		}
+		buf.WriteRune(r)
+	}
+	return buf.String()
+}
+
+// FoldDup reports a pair of strings from the list that are
+// equal according to strings.EqualFold.
+// It returns "", "" if there are no such strings.
+func FoldDup(list []string) (string, string) {
+	clash := map[string]string{}
+	for _, s := range list {
+		fold := toFold(s)
+		if t := clash[fold]; t != "" {
+			if s > t {
+				s, t = t, s
+			}
+			return s, t
+		}
+		clash[fold] = s
+	}
+	return "", ""
+}
+
+// Contains reports whether x contains s.
+func Contains(x []string, s string) bool {
+	for _, t := range x {
+		if t == s {
+			return true
+		}
+	}
+	return false
+}

src/cmd/go/main.go

@@ -7,6 +7,7 @@ package main
 import (
 	"bufio"
 	"bytes"
+	"cmd/go/internal/str"
 	"flag"
 	"fmt"
 	"go/build"
@@ -453,7 +454,7 @@ func exitIfErrors() {
 }
 
 func run(cmdargs ...interface{}) {
-	cmdline := stringList(cmdargs...)
+	cmdline := str.StringList(cmdargs...)
 	if buildN || buildX {
 		fmt.Printf("%s\n", strings.Join(cmdline, " "))
 		if buildN {
@@ -730,77 +731,3 @@ func matchPackagesInFS(pattern string) []string {
 	})
 	return pkgs
 }
-
-// stringList's arguments should be a sequence of string or []string values.
-// stringList flattens them into a single []string.
-func stringList(args ...interface{}) []string {
-	var x []string
-	for _, arg := range args {
-		switch arg := arg.(type) {
-		case []string:
-			x = append(x, arg...)
-		case string:
-			x = append(x, arg)
-		default:
-			panic("stringList: invalid argument of type " + fmt.Sprintf("%T", arg))
-		}
-	}
-	return x
-}
-
-// toFold returns a string with the property that
-//	strings.EqualFold(s, t) iff toFold(s) == toFold(t)
-// This lets us test a large set of strings for fold-equivalent
-// duplicates without making a quadratic number of calls
-// to EqualFold. Note that strings.ToUpper and strings.ToLower
-// have the desired property in some corner cases.
-func toFold(s string) string {
-	// Fast path: all ASCII, no upper case.
-	// Most paths look like this already.
-	for i := 0; i < len(s); i++ {
-		c := s[i]
-		if c >= utf8.RuneSelf || 'A' <= c && c <= 'Z' {
-			goto Slow
-		}
-	}
-	return s
-
-Slow:
-	var buf bytes.Buffer
-	for _, r := range s {
-		// SimpleFold(x) cycles to the next equivalent rune > x
-		// or wraps around to smaller values. Iterate until it wraps,
-		// and we've found the minimum value.
-		for {
-			r0 := r
-			r = unicode.SimpleFold(r0)
-			if r <= r0 {
-				break
-			}
-		}
-		// Exception to allow fast path above: A-Z => a-z
-		if 'A' <= r && r <= 'Z' {
-			r += 'a' - 'A'
-		}
-		buf.WriteRune(r)
-	}
-	return buf.String()
-}
-
-// foldDup reports a pair of strings from the list that are
-// equal according to strings.EqualFold.
-// It returns "", "" if there are no such strings.
-func foldDup(list []string) (string, string) {
-	clash := map[string]string{}
-	for _, s := range list {
-		fold := toFold(s)
-		if t := clash[fold]; t != "" {
-			if s > t {
-				s, t = t, s
-			}
-			return s, t
-		}
-		clash[fold] = s
-	}
-	return "", ""
-}