all: use sort.Slice where applicable

I avoided anywhere in the compiler or things which might be used by
the compiler in the future, since they need to build with Go 1.4.

I also avoided anywhere where there was no benefit to changing it.

I probably missed some.

Updates #16721

Change-Id: Ib3c895ff475c6dec2d4322393faaf8cb6a6d4956
Reviewed-on: https://go-review.googlesource.com/30250
TryBot-Result: Gobot Gobot <gobot@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Andrew Gerrand <adg@golang.org>

8 files changed, 39 insertions, 123 deletions

diff --git a/src/cmd/go/test.go b/src/cmd/go/test.go
index 138d46c381..4b65c1ccdc 100644
--- a/src/cmd/go/test.go
+++ b/src/cmd/go/test.go
@@ -1397,7 +1397,7 @@ func (t *testFuncs) load(filename, pkg string, doImport, seen *bool) error {
 		}
 	}
 	ex := doc.Examples(f)
-	sort.Sort(byOrder(ex))
+	sort.Slice(ex, func(i, j int) bool { return ex[i].Order < ex[j].Order })
 	for _, e := range ex {
 		*doImport = true // import test file whether executed or not
 		if e.Output == "" && !e.EmptyOutput {
@@ -1419,12 +1419,6 @@ func checkTestFunc(fn *ast.FuncDecl, arg string) error {
 	return nil
 }
 
-type byOrder []*doc.Example
-
-func (x byOrder) Len() int           { return len(x) }
-func (x byOrder) Swap(i, j int)      { x[i], x[j] = x[j], x[i] }
-func (x byOrder) Less(i, j int) bool { return x[i].Order < x[j].Order }
-
 var testmainTmpl = template.Must(template.New("main").Parse(`
 package main
 
diff --git a/src/cmd/nm/nm.go b/src/cmd/nm/nm.go
index 462c4c510f..4384af8fae 100644
--- a/src/cmd/nm/nm.go
+++ b/src/cmd/nm/nm.go
@@ -103,11 +103,11 @@ func nm(file string) {
 
 	switch *sortOrder {
 	case "address":
-		sort.Sort(byAddr(syms))
+		sort.Slice(syms, func(i, j int) bool { return syms[i].Addr < syms[j].Addr })
 	case "name":
-		sort.Sort(byName(syms))
+		sort.Slice(syms, func(i, j int) bool { return syms[i].Name < syms[j].Name })
 	case "size":
-		sort.Sort(bySize(syms))
+		sort.Slice(syms, func(i, j int) bool { return syms[i].Size > syms[j].Size })
 	}
 
 	w := bufio.NewWriter(os.Stdout)
@@ -131,21 +131,3 @@ func nm(file string) {
 	}
 	w.Flush()
 }
-
-type byAddr []objfile.Sym
-
-func (x byAddr) Len() int           { return len(x) }
-func (x byAddr) Swap(i, j int)      { x[i], x[j] = x[j], x[i] }
-func (x byAddr) Less(i, j int) bool { return x[i].Addr < x[j].Addr }
-
-type byName []objfile.Sym
-
-func (x byName) Len() int           { return len(x) }
-func (x byName) Swap(i, j int)      { x[i], x[j] = x[j], x[i] }
-func (x byName) Less(i, j int) bool { return x[i].Name < x[j].Name }
-
-type bySize []objfile.Sym
-
-func (x bySize) Len() int           { return len(x) }
-func (x bySize) Swap(i, j int)      { x[i], x[j] = x[j], x[i] }
-func (x bySize) Less(i, j int) bool { return x[i].Size > x[j].Size }
diff --git a/src/encoding/json/encode.go b/src/encoding/json/encode.go
index d3e0c85b9d..aab912601a 100644
--- a/src/encoding/json/encode.go
+++ b/src/encoding/json/encode.go
@@ -636,7 +636,7 @@ func (me *mapEncoder) encode(e *encodeState, v reflect.Value, opts encOpts) {
 			e.error(&MarshalerError{v.Type(), err})
 		}
 	}
-	sort.Sort(byString(sv))
+	sort.Slice(sv, func(i, j int) bool { return sv[i].s < sv[j].s })
 
 	for i, kv := range sv {
 		if i > 0 {
@@ -835,15 +835,6 @@ func (w *reflectWithString) resolve() error {
 	panic("unexpected map key type")
 }
 
-// byString is a slice of reflectWithString where the reflect.Value is either
-// a string or an encoding.TextMarshaler.
-// It implements the methods to sort by string.
-type byString []reflectWithString
-
-func (sv byString) Len() int           { return len(sv) }
-func (sv byString) Swap(i, j int)      { sv[i], sv[j] = sv[j], sv[i] }
-func (sv byString) Less(i, j int) bool { return sv[i].s < sv[j].s }
-
 // NOTE: keep in sync with stringBytes below.
 func (e *encodeState) string(s string, escapeHTML bool) int {
 	len0 := e.Len()
@@ -1017,28 +1008,6 @@ func fillField(f field) field {
 	return f
 }
 
-// byName sorts field by name, breaking ties with depth,
-// then breaking ties with "name came from json tag", then
-// breaking ties with index sequence.
-type byName []field
-
-func (x byName) Len() int { return len(x) }
-
-func (x byName) Swap(i, j int) { x[i], x[j] = x[j], x[i] }
-
-func (x byName) Less(i, j int) bool {
-	if x[i].name != x[j].name {
-		return x[i].name < x[j].name
-	}
-	if len(x[i].index) != len(x[j].index) {
-		return len(x[i].index) < len(x[j].index)
-	}
-	if x[i].tag != x[j].tag {
-		return x[i].tag
-	}
-	return byIndex(x).Less(i, j)
-}
-
 // byIndex sorts field by index sequence.
 type byIndex []field
 
@@ -1156,7 +1125,22 @@ func typeFields(t reflect.Type) []field {
 		}
 	}
 
-	sort.Sort(byName(fields))
+	sort.Slice(fields, func(i, j int) bool {
+		x := fields
+		// sort field by name, breaking ties with depth, then
+		// breaking ties with "name came from json tag", then
+		// breaking ties with index sequence.
+		if x[i].name != x[j].name {
+			return x[i].name < x[j].name
+		}
+		if len(x[i].index) != len(x[j].index) {
+			return len(x[i].index) < len(x[j].index)
+		}
+		if x[i].tag != x[j].tag {
+			return x[i].tag
+		}
+		return byIndex(x).Less(i, j)
+	})
 
 	// Delete all fields that are hidden by the Go rules for embedded fields,
 	// except that fields with JSON tags are promoted.
diff --git a/src/io/ioutil/ioutil.go b/src/io/ioutil/ioutil.go
index 8ecbb2de76..f0da616830 100644
--- a/src/io/ioutil/ioutil.go
+++ b/src/io/ioutil/ioutil.go
@@ -88,13 +88,6 @@ func WriteFile(filename string, data []byte, perm os.FileMode) error {
 	return err
 }
 
-// byName implements sort.Interface.
-type byName []os.FileInfo
-
-func (f byName) Len() int           { return len(f) }
-func (f byName) Less(i, j int) bool { return f[i].Name() < f[j].Name() }
-func (f byName) Swap(i, j int)      { f[i], f[j] = f[j], f[i] }
-
 // ReadDir reads the directory named by dirname and returns
 // a list of directory entries sorted by filename.
 func ReadDir(dirname string) ([]os.FileInfo, error) {
@@ -107,7 +100,7 @@ func ReadDir(dirname string) ([]os.FileInfo, error) {
 	if err != nil {
 		return nil, err
 	}
-	sort.Sort(byName(list))
+	sort.Slice(list, func(i, j int) bool { return list[i].Name() < list[j].Name() })
 	return list, nil
 }
 
diff --git a/src/net/http/cookiejar/jar.go b/src/net/http/cookiejar/jar.go
index ca0fdc57d7..f89abbcd18 100644
--- a/src/net/http/cookiejar/jar.go
+++ b/src/net/http/cookiejar/jar.go
@@ -147,24 +147,6 @@ func hasDotSuffix(s, suffix string) bool {
 	return len(s) > len(suffix) && s[len(s)-len(suffix)-1] == '.' && s[len(s)-len(suffix):] == suffix
 }
 
-// byPathLength is a []entry sort.Interface that sorts according to RFC 6265
-// section 5.4 point 2: by longest path and then by earliest creation time.
-type byPathLength []entry
-
-func (s byPathLength) Len() int { return len(s) }
-
-func (s byPathLength) Less(i, j int) bool {
-	if len(s[i].Path) != len(s[j].Path) {
-		return len(s[i].Path) > len(s[j].Path)
-	}
-	if !s[i].Creation.Equal(s[j].Creation) {
-		return s[i].Creation.Before(s[j].Creation)
-	}
-	return s[i].seqNum < s[j].seqNum
-}
-
-func (s byPathLength) Swap(i, j int) { s[i], s[j] = s[j], s[i] }
-
 // Cookies implements the Cookies method of the http.CookieJar interface.
 //
 // It returns an empty slice if the URL's scheme is not HTTP or HTTPS.
@@ -221,7 +203,18 @@ func (j *Jar) cookies(u *url.URL, now time.Time) (cookies []*http.Cookie) {
 		}
 	}
 
-	sort.Sort(byPathLength(selected))
+	// sort according to RFC 6265 section 5.4 point 2: by longest
+	// path and then by earliest creation time.
+	sort.Slice(selected, func(i, j int) bool {
+		s := selected
+		if len(s[i].Path) != len(s[j].Path) {
+			return len(s[i].Path) > len(s[j].Path)
+		}
+		if !s[i].Creation.Equal(s[j].Creation) {
+			return s[i].Creation.Before(s[j].Creation)
+		}
+		return s[i].seqNum < s[j].seqNum
+	})
 	for _, e := range selected {
 		cookies = append(cookies, &http.Cookie{Name: e.Name, Value: e.Value})
 	}
diff --git a/src/net/http/fs.go b/src/net/http/fs.go
index 969ca65b69..4ab74ff640 100644
--- a/src/net/http/fs.go
+++ b/src/net/http/fs.go
@@ -77,7 +77,7 @@ func dirList(w ResponseWriter, f File) {
 		Error(w, "Error reading directory", StatusInternalServerError)
 		return
 	}
-	sort.Sort(byName(dirs))
+	sort.Slice(dirs, func(i, j int) bool { return dirs[i].Name() < dirs[j].Name() })
 
 	w.Header().Set("Content-Type", "text/html; charset=utf-8")
 	fmt.Fprintf(w, "<pre>\n")
@@ -647,9 +647,3 @@ func sumRangesSize(ranges []httpRange) (size int64) {
 	}
 	return
 }
-
-type byName []os.FileInfo
-
-func (s byName) Len() int           { return len(s) }
-func (s byName) Less(i, j int) bool { return s[i].Name() < s[j].Name() }
-func (s byName) Swap(i, j int)      { s[i], s[j] = s[j], s[i] }
diff --git a/src/runtime/debug/garbage.go b/src/runtime/debug/garbage.go
index 8144497177..c82c024235 100644
--- a/src/runtime/debug/garbage.go
+++ b/src/runtime/debug/garbage.go
@@ -71,7 +71,7 @@ func ReadGCStats(stats *GCStats) {
 			// See the allocation at the top of the function.
 			sorted := stats.Pause[n : n+n]
 			copy(sorted, stats.Pause)
-			sort.Sort(byDuration(sorted))
+			sort.Slice(sorted, func(i, j int) bool { return sorted[i] < sorted[j] })
 			nq := len(stats.PauseQuantiles) - 1
 			for i := 0; i < nq; i++ {
 				stats.PauseQuantiles[i] = sorted[len(sorted)*i/nq]
@@ -81,12 +81,6 @@ func ReadGCStats(stats *GCStats) {
 	}
 }
 
-type byDuration []time.Duration
-
-func (x byDuration) Len() int           { return len(x) }
-func (x byDuration) Swap(i, j int)      { x[i], x[j] = x[j], x[i] }
-func (x byDuration) Less(i, j int) bool { return x[i] < x[j] }
-
 // SetGCPercent sets the garbage collection target percentage:
 // a collection is triggered when the ratio of freshly allocated data
 // to live data remaining after the previous collection reaches this percentage.
diff --git a/src/runtime/pprof/pprof.go b/src/runtime/pprof/pprof.go
index 1fc9568b2f..b4dd1c4173 100644
--- a/src/runtime/pprof/pprof.go
+++ b/src/runtime/pprof/pprof.go
@@ -207,16 +207,10 @@ func Profiles() []*Profile {
 		all = append(all, p)
 	}
 
-	sort.Sort(byName(all))
+	sort.Slice(all, func(i, j int) bool { return all[i].name < all[j].name })
 	return all
 }
 
-type byName []*Profile
-
-func (x byName) Len() int           { return len(x) }
-func (x byName) Swap(i, j int)      { x[i], x[j] = x[j], x[i] }
-func (x byName) Less(i, j int) bool { return x[i].name < x[j].name }
-
 // Name returns this profile's name, which can be passed to Lookup to reobtain the profile.
 func (p *Profile) Name() string {
 	return p.name
@@ -435,12 +429,6 @@ func printStackRecord(w io.Writer, stk []uintptr, allFrames bool) {
 
 // Interface to system profiles.
 
-type byInUseBytes []runtime.MemProfileRecord
-
-func (x byInUseBytes) Len() int           { return len(x) }
-func (x byInUseBytes) Swap(i, j int)      { x[i], x[j] = x[j], x[i] }
-func (x byInUseBytes) Less(i, j int) bool { return x[i].InUseBytes() > x[j].InUseBytes() }
-
 // WriteHeapProfile is shorthand for Lookup("heap").WriteTo(w, 0).
 // It is preserved for backwards compatibility.
 func WriteHeapProfile(w io.Writer) error {
@@ -476,7 +464,7 @@ func writeHeap(w io.Writer, debug int) error {
 		// Profile grew; try again.
 	}
 
-	sort.Sort(byInUseBytes(p))
+	sort.Slice(p, func(i, j int) bool { return p[i].InUseBytes() > p[j].InUseBytes() })
 
 	b := bufio.NewWriter(w)
 	var tw *tabwriter.Writer
@@ -735,12 +723,6 @@ func StopCPUProfile() {
 	<-cpu.done
 }
 
-type byCycles []runtime.BlockProfileRecord
-
-func (x byCycles) Len() int           { return len(x) }
-func (x byCycles) Swap(i, j int)      { x[i], x[j] = x[j], x[i] }
-func (x byCycles) Less(i, j int) bool { return x[i].Cycles > x[j].Cycles }
-
 // countBlock returns the number of records in the blocking profile.
 func countBlock() int {
 	n, _ := runtime.BlockProfile(nil)
@@ -760,7 +742,7 @@ func writeBlock(w io.Writer, debug int) error {
 		}
 	}
 
-	sort.Sort(byCycles(p))
+	sort.Slice(p, func(i, j int) bool { return p[i].Cycles > p[j].Cycles })
 
 	b := bufio.NewWriter(w)
 	var tw *tabwriter.Writer