Golang sort.Slice函数代码示例

func (me *mapEncoder) encode(e *encodeState, v reflect.Value, opts encOpts) {
	if v.IsNil() {
		e.WriteString("null")
		return
	}
	e.WriteByte('{')

	// Extract and sort the keys.
	keys := v.MapKeys()
	sv := make([]reflectWithString, len(keys))
	for i, v := range keys {
		sv[i].v = v
		if err := sv[i].resolve(); err != nil {
			e.error(&MarshalerError{v.Type(), err})
		}
	}
	sort.Slice(sv, func(i, j int) bool { return sv[i].s < sv[j].s })

	for i, kv := range sv {
		if i > 0 {
			e.WriteByte(',')
		}
		e.string(kv.s, opts.escapeHTML)
		e.WriteByte(':')
		me.elemEnc(e, v.MapIndex(kv.v), opts)
	}
	e.WriteByte('}')
}

func dirList(w ResponseWriter, f File) {
	dirs, err := f.Readdir(-1)
	if err != nil {
		// TODO: log err.Error() to the Server.ErrorLog, once it's possible
		// for a handler to get at its Server via the ResponseWriter. See
		// Issue 12438.
		Error(w, "Error reading directory", StatusInternalServerError)
		return
	}
	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")
	for _, d := range dirs {
		name := d.Name()
		if d.IsDir() {
			name += "/"
		}
		// name may contain '?' or '#', which must be escaped to remain
		// part of the URL path, and not indicate the start of a query
		// string or fragment.
		url := url.URL{Path: name}
		fmt.Fprintf(w, "<a href=\"%s\">%s</a>\n", url.String(), htmlReplacer.Replace(name))
	}
	fmt.Fprintf(w, "</pre>\n")
}

func nm(file string) {
	f, err := objfile.Open(file)
	if err != nil {
		errorf("%v", err)
		return
	}
	defer f.Close()

	syms, err := f.Symbols()
	if err != nil {
		errorf("reading %s: %v", file, err)
	}
	if len(syms) == 0 {
		errorf("reading %s: no symbols", file)
	}

	switch *sortOrder {
	case "address":
		sort.Slice(syms, func(i, j int) bool { return syms[i].Addr < syms[j].Addr })
	case "name":
		sort.Slice(syms, func(i, j int) bool { return syms[i].Name < syms[j].Name })
	case "size":
		sort.Slice(syms, func(i, j int) bool { return syms[i].Size > syms[j].Size })
	}

	w := bufio.NewWriter(os.Stdout)
	for _, sym := range syms {
		if filePrefix {
			fmt.Fprintf(w, "%s:\t", file)
		}
		if sym.Code == 'U' {
			fmt.Fprintf(w, "%8s", "")
		} else {
			fmt.Fprintf(w, "%8x", sym.Addr)
		}
		if *printSize {
			fmt.Fprintf(w, " %10d", sym.Size)
		}
		fmt.Fprintf(w, " %c %s", sym.Code, sym.Name)
		if *printType && sym.Type != "" {
			fmt.Fprintf(w, " %s", sym.Type)
		}
		fmt.Fprintf(w, "\n")
	}
	w.Flush()
}

func ExampleSlice() {
	people := []struct {
		Name string
		Age  int
	}{
		{"Gopher", 7},
		{"Alice", 55},
		{"Vera", 24},
		{"Bob", 75},
	}
	sort.Slice(people, func(i, j int) bool { return people[i].Name < people[j].Name })
	fmt.Println("By name:", people)

	sort.Slice(people, func(i, j int) bool { return people[i].Age < people[j].Age })
	fmt.Println("By age:", people)
	// Output: By name: [{Alice 55} {Bob 75} {Gopher 7} {Vera 24}]
	// By age: [{Gopher 7} {Vera 24} {Alice 55} {Bob 75}]
}

func (d *MultiDialer) pickupTLSAddrs(addrs []string, n int) []string {
	if len(addrs) <= n {
		return addrs
	}

	type racer struct {
		addr     string
		duration time.Duration
	}

	goodAddrs := make([]racer, 0)
	unknownAddrs := make([]string, 0)
	badAddrs := make([]string, 0)

	for _, addr := range addrs {
		if duration, ok := d.TLSConnDuration.GetNotStale(addr); ok {
			if d, ok := duration.(time.Duration); !ok {
				glog.Errorf("%#v for %#v is not a time.Duration", duration, addr)
			} else {
				goodAddrs = append(goodAddrs, racer{addr, d})
			}
		} else if e, ok := d.TLSConnError.GetNotStale(addr); ok {
			if _, ok := e.(error); !ok {
				glog.Errorf("%#v for %#v is not a error", e, addr)
			} else {
				badAddrs = append(badAddrs, addr)
			}
		} else {
			unknownAddrs = append(unknownAddrs, addr)
		}
	}

	addrs1 := make([]string, 0, n)

	sort.Slice(goodAddrs, func(i, j int) bool { return goodAddrs[i].duration < goodAddrs[j].duration })
	if len(goodAddrs) > n/2 {
		goodAddrs = goodAddrs[:n/2]
	}
	for _, r := range goodAddrs {
		addrs1 = append(addrs1, r.addr)
	}

	for _, addrs2 := range [][]string{unknownAddrs, badAddrs} {
		if len(addrs1) < n && len(addrs2) > 0 {
			m := n - len(addrs1)
			if len(addrs2) > m {
				ShuffleStringsN(addrs2, m)
				addrs2 = addrs2[:m]
			}
			addrs1 = append(addrs1, addrs2...)
		}
	}

	return addrs1
}

// Profiles returns a slice of all the known profiles, sorted by name.
func Profiles() []*Profile {
	lockProfiles()
	defer unlockProfiles()

	all := make([]*Profile, 0, len(profiles.m))
	for _, p := range profiles.m {
		all = append(all, p)
	}

	sort.Slice(all, func(i, j int) bool { return all[i].name < all[j].name })
	return all
}

// ReadGCStats reads statistics about garbage collection into stats.
// The number of entries in the pause history is system-dependent;
// stats.Pause slice will be reused if large enough, reallocated otherwise.
// ReadGCStats may use the full capacity of the stats.Pause slice.
// If stats.PauseQuantiles is non-empty, ReadGCStats fills it with quantiles
// summarizing the distribution of pause time. For example, if
// len(stats.PauseQuantiles) is 5, it will be filled with the minimum,
// 25%, 50%, 75%, and maximum pause times.
func ReadGCStats(stats *GCStats) {
	// Create a buffer with space for at least two copies of the
	// pause history tracked by the runtime. One will be returned
	// to the caller and the other will be used as transfer buffer
	// for end times history and as a temporary buffer for
	// computing quantiles.
	const maxPause = len(((*runtime.MemStats)(nil)).PauseNs)
	if cap(stats.Pause) < 2*maxPause+3 {
		stats.Pause = make([]time.Duration, 2*maxPause+3)
	}

	// readGCStats fills in the pause and end times histories (up to
	// maxPause entries) and then three more: Unix ns time of last GC,
	// number of GC, and total pause time in nanoseconds. Here we
	// depend on the fact that time.Duration's native unit is
	// nanoseconds, so the pauses and the total pause time do not need
	// any conversion.
	readGCStats(&stats.Pause)
	n := len(stats.Pause) - 3
	stats.LastGC = time.Unix(0, int64(stats.Pause[n]))
	stats.NumGC = int64(stats.Pause[n+1])
	stats.PauseTotal = stats.Pause[n+2]
	n /= 2 // buffer holds pauses and end times
	stats.Pause = stats.Pause[:n]

	if cap(stats.PauseEnd) < maxPause {
		stats.PauseEnd = make([]time.Time, 0, maxPause)
	}
	stats.PauseEnd = stats.PauseEnd[:0]
	for _, ns := range stats.Pause[n : n+n] {
		stats.PauseEnd = append(stats.PauseEnd, time.Unix(0, int64(ns)))
	}

	if len(stats.PauseQuantiles) > 0 {
		if n == 0 {
			for i := range stats.PauseQuantiles {
				stats.PauseQuantiles[i] = 0
			}
		} else {
			// There's room for a second copy of the data in stats.Pause.
			// See the allocation at the top of the function.
			sorted := stats.Pause[n : n+n]
			copy(sorted, stats.Pause)
			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]
			}
			stats.PauseQuantiles[nq] = sorted[len(sorted)-1]
		}
	}
}

// ReadDir reads the directory named by dirname and returns
// a list of directory entries sorted by filename.
func ReadDir(dirname string) ([]os.FileInfo, error) {
	f, err := os.Open(dirname)
	if err != nil {
		return nil, err
	}
	list, err := f.Readdir(-1)
	f.Close()
	if err != nil {
		return nil, err
	}
	sort.Slice(list, func(i, j int) bool { return list[i].Name() < list[j].Name() })
	return list, nil
}

func (t *testFuncs) load(filename, pkg string, doImport, seen *bool) error {
	f, err := parser.ParseFile(testFileSet, filename, nil, parser.ParseComments)
	if err != nil {
		return expandScanner(err)
	}
	for _, d := range f.Decls {
		n, ok := d.(*ast.FuncDecl)
		if !ok {
			continue
		}
		if n.Recv != nil {
			continue
		}
		name := n.Name.String()
		switch {
		case name == "TestMain" && isTestFunc(n, "M"):
			if t.TestMain != nil {
				return errors.New("multiple definitions of TestMain")
			}
			t.TestMain = &testFunc{pkg, name, "", false}
			*doImport, *seen = true, true
		case isTest(name, "Test"):
			err := checkTestFunc(n, "T")
			if err != nil {
				return err
			}
			t.Tests = append(t.Tests, testFunc{pkg, name, "", false})
			*doImport, *seen = true, true
		case isTest(name, "Benchmark"):
			err := checkTestFunc(n, "B")
			if err != nil {
				return err
			}
			t.Benchmarks = append(t.Benchmarks, testFunc{pkg, name, "", false})
			*doImport, *seen = true, true
		}
	}
	ex := doc.Examples(f)
	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 {
			// Don't run examples with no output.
			continue
		}
		t.Examples = append(t.Examples, testFunc{pkg, "Example" + e.Name, e.Output, e.Unordered})
		*seen = true
	}
	return nil
}

// writeMutex writes the current mutex profile to w.
func writeMutex(w io.Writer, debug int) error {
	// TODO(pjw): too much common code with writeBlock. FIX!
	var p []runtime.BlockProfileRecord
	n, ok := runtime.MutexProfile(nil)
	for {
		p = make([]runtime.BlockProfileRecord, n+50)
		n, ok = runtime.MutexProfile(p)
		if ok {
			p = p[:n]
			break
		}
	}

	sort.Slice(p, func(i, j int) bool { return p[i].Cycles > p[j].Cycles })

	b := bufio.NewWriter(w)
	var tw *tabwriter.Writer
	w = b
	if debug > 0 {
		tw = tabwriter.NewWriter(w, 1, 8, 1, '\t', 0)
		w = tw
	}

	fmt.Fprintf(w, "--- mutex:\n")
	fmt.Fprintf(w, "cycles/second=%v\n", runtime_cyclesPerSecond())
	fmt.Fprintf(w, "sampling period=%d\n", runtime.SetMutexProfileFraction(-1))
	for i := range p {
		r := &p[i]
		fmt.Fprintf(w, "%v %v @", r.Cycles, r.Count)
		for _, pc := range r.Stack() {
			fmt.Fprintf(w, " %#x", pc)
		}
		fmt.Fprint(w, "\n")
		if debug > 0 {
			printStackRecord(w, r.Stack(), true)
		}
	}

	if tw != nil {
		tw.Flush()
	}
	return b.Flush()
}

// writeBlock writes the current blocking profile to w.
func writeBlock(w io.Writer, debug int) error {
	var p []runtime.BlockProfileRecord
	n, ok := runtime.BlockProfile(nil)
	for {
		p = make([]runtime.BlockProfileRecord, n+50)
		n, ok = runtime.BlockProfile(p)
		if ok {
			p = p[:n]
			break
		}
	}

	sort.Slice(p, func(i, j int) bool { return p[i].Cycles > p[j].Cycles })

	b := bufio.NewWriter(w)
	var tw *tabwriter.Writer
	w = b
	if debug > 0 {
		tw = tabwriter.NewWriter(w, 1, 8, 1, '\t', 0)
		w = tw
	}

	fmt.Fprintf(w, "--- contention:\n")
	fmt.Fprintf(w, "cycles/second=%v\n", runtime_cyclesPerSecond())
	for i := range p {
		r := &p[i]
		fmt.Fprintf(w, "%v %v @", r.Cycles, r.Count)
		for _, pc := range r.Stack() {
			fmt.Fprintf(w, " %#x", pc)
		}
		fmt.Fprint(w, "\n")
		if debug > 0 {
			printStackRecord(w, r.Stack(), true)
		}
	}

	if tw != nil {
		tw.Flush()
	}
	return b.Flush()
}

// writeBlock writes the current blocking profile to w.
func writeBlock(w io.Writer, debug int) error {
	var p []runtime.BlockProfileRecord
	n, ok := runtime.BlockProfile(nil)
	for {
		// Code by analogy with writeBlock func
		p = make([]runtime.BlockProfileRecord, n+50)
		n, ok = runtime.BlockProfile(p)
		if ok {
			p = p[:n]
			break
		}
	}

	sort.Slice(p, func(i, j int) bool { return p[i].Cycles > p[j].Cycles })

	prof := &profile.Profile{
		PeriodType: &profile.ValueType{Type: "contentions", Unit: "count"},
		Period:     1,
		SampleType: []*profile.ValueType{
			{Type: "contentions", Unit: "count"},
			{Type: "delay", Unit: "nanoseconds"},
		},
	}

	cpuHz := runtime_cyclesPerSecond()
	locs := make(map[uint64]*profile.Location)
	for i := range p {
		r := &p[i]
		var v1, v2 int64
		v1 = r.Cycles
		v2 = r.Count
		if prof.Period > 0 {
			if cpuHz > 0 {
				cpuGHz := float64(cpuHz) / 1e9
				v1 = int64(float64(v1) * float64(prof.Period) / cpuGHz)
			}
			v2 = v2 * prof.Period
		}

		value := []int64{v2, v1}
		var sloc []*profile.Location

		for _, pc := range r.Stack() {
			addr := uint64(pc)
			addr--
			loc := locs[addr]
			if locs[addr] == nil {
				loc = &profile.Location{
					Address: addr,
				}
				prof.Location = append(prof.Location, loc)
				locs[addr] = loc
			}
			sloc = append(sloc, loc)
		}
		prof.Sample = append(prof.Sample, &profile.Sample{
			Value:    value,
			Location: sloc,
		})
	}

	prof.RemapAll()
	protopprof.Symbolize(prof)
	return prof.Write(w)
}

// writeHeap writes the current runtime heap profile to w.
func writeHeap(w io.Writer, debug int) error {
	// Find out how many records there are (MemProfile(nil, true)),
	// allocate that many records, and get the data.
	// There's a race—more records might be added between
	// the two calls—so allocate a few extra records for safety
	// and also try again if we're very unlucky.
	// The loop should only execute one iteration in the common case.
	var p []runtime.MemProfileRecord
	n, ok := runtime.MemProfile(nil, true)
	for {
		p = make([]runtime.MemProfileRecord, n+50)
		n, ok = runtime.MemProfile(p, true)
		if ok {
			p = p[0:n]
			break
		}
	}

	sort.Slice(p, func(i, j int) bool { return p[i].InUseBytes() > p[j].InUseBytes() })

	var total runtime.MemProfileRecord
	for i := range p {
		r := &p[i]
		total.AllocBytes += r.AllocBytes
		total.AllocObjects += r.AllocObjects
		total.FreeBytes += r.FreeBytes
		total.FreeObjects += r.FreeObjects
	}

	prof := &profile.Profile{
		PeriodType: &profile.ValueType{Type: "space", Unit: "bytes"},
		SampleType: []*profile.ValueType{
			{Type: "alloc_objects", Unit: "count"},
			{Type: "alloc_space", Unit: "bytes"},
			{Type: "inuse_objects", Unit: "count"},
			{Type: "inuse_space", Unit: "bytes"},
		},
		Period: int64(runtime.MemProfileRate),
	}

	locs := make(map[uint64]*(profile.Location))
	for i := range p {
		var v1, v2, v3, v4, blocksize int64
		r := &p[i]
		v1, v2 = int64(r.InUseObjects()), int64(r.InUseBytes())
		v3, v4 = int64(r.AllocObjects), int64(r.AllocBytes)
		if (v1 == 0 && v2 != 0) || (v3 == 0 && v4 != 0) {
			return fmt.Errorf("error writing memory profile: inuse object count was 0 but inuse bytes was %d", v2)
		} else {
			if v1 != 0 {
				blocksize = v2 / v1
				v1, v2 = scaleHeapSample(v1, v2, prof.Period)
			}
			if v3 != 0 {
				v3, v4 = scaleHeapSample(v3, v4, prof.Period)
			}
		}
		value := []int64{v1, v2, v3, v4}
		var sloc []*profile.Location
		for _, pc := range r.Stack() {
			addr := uint64(pc)
			addr--
			loc := locs[addr]
			if locs[addr] == nil {
				loc = &(profile.Location{
					Address: addr,
				})
				prof.Location = append(prof.Location, loc)
				locs[addr] = loc
			}
			sloc = append(sloc, loc)
		}
		prof.Sample = append(prof.Sample, &profile.Sample{
			Value:    value,
			Location: sloc,
			NumLabel: map[string][]int64{"bytes": {blocksize}},
		})
	}
	prof.RemapAll()
	protopprof.Symbolize(prof)
	return prof.Write(w)
}

// writeHeap writes the current runtime heap profile to w.
func writeHeap(w io.Writer, debug int) error {
	// Find out how many records there are (MemProfile(nil, true)),
	// allocate that many records, and get the data.
	// There's a race—more records might be added between
	// the two calls—so allocate a few extra records for safety
	// and also try again if we're very unlucky.
	// The loop should only execute one iteration in the common case.
	var p []runtime.MemProfileRecord
	n, ok := runtime.MemProfile(nil, true)
	for {
		// Allocate room for a slightly bigger profile,
		// in case a few more entries have been added
		// since the call to MemProfile.
		p = make([]runtime.MemProfileRecord, n+50)
		n, ok = runtime.MemProfile(p, true)
		if ok {
			p = p[0:n]
			break
		}
		// Profile grew; try again.
	}

	if debug == 0 {
		pp := protopprof.EncodeMemProfile(p, int64(runtime.MemProfileRate), time.Now())
		return pp.Write(w)
	}

	sort.Slice(p, func(i, j int) bool { return p[i].InUseBytes() > p[j].InUseBytes() })

	b := bufio.NewWriter(w)
	tw := tabwriter.NewWriter(b, 1, 8, 1, '\t', 0)
	w = tw

	var total runtime.MemProfileRecord
	for i := range p {
		r := &p[i]
		total.AllocBytes += r.AllocBytes
		total.AllocObjects += r.AllocObjects
		total.FreeBytes += r.FreeBytes
		total.FreeObjects += r.FreeObjects
	}

	// Technically the rate is MemProfileRate not 2*MemProfileRate,
	// but early versions of the C++ heap profiler reported 2*MemProfileRate,
	// so that's what pprof has come to expect.
	fmt.Fprintf(w, "heap profile: %d: %d [%d: %d] @ heap/%d\n",
		total.InUseObjects(), total.InUseBytes(),
		total.AllocObjects, total.AllocBytes,
		2*runtime.MemProfileRate)

	for i := range p {
		r := &p[i]
		fmt.Fprintf(w, "%d: %d [%d: %d] @",
			r.InUseObjects(), r.InUseBytes(),
			r.AllocObjects, r.AllocBytes)
		for _, pc := range r.Stack() {
			fmt.Fprintf(w, " %#x", pc)
		}
		fmt.Fprintf(w, "\n")
		printStackRecord(w, r.Stack(), false)
	}

	// Print memstats information too.
	// Pprof will ignore, but useful for people
	s := new(runtime.MemStats)
	runtime.ReadMemStats(s)
	fmt.Fprintf(w, "\n# runtime.MemStats\n")
	fmt.Fprintf(w, "# Alloc = %d\n", s.Alloc)
	fmt.Fprintf(w, "# TotalAlloc = %d\n", s.TotalAlloc)
	fmt.Fprintf(w, "# Sys = %d\n", s.Sys)
	fmt.Fprintf(w, "# Lookups = %d\n", s.Lookups)
	fmt.Fprintf(w, "# Mallocs = %d\n", s.Mallocs)
	fmt.Fprintf(w, "# Frees = %d\n", s.Frees)

	fmt.Fprintf(w, "# HeapAlloc = %d\n", s.HeapAlloc)
	fmt.Fprintf(w, "# HeapSys = %d\n", s.HeapSys)
	fmt.Fprintf(w, "# HeapIdle = %d\n", s.HeapIdle)
	fmt.Fprintf(w, "# HeapInuse = %d\n", s.HeapInuse)
	fmt.Fprintf(w, "# HeapReleased = %d\n", s.HeapReleased)
	fmt.Fprintf(w, "# HeapObjects = %d\n", s.HeapObjects)

	fmt.Fprintf(w, "# Stack = %d / %d\n", s.StackInuse, s.StackSys)
	fmt.Fprintf(w, "# MSpan = %d / %d\n", s.MSpanInuse, s.MSpanSys)
	fmt.Fprintf(w, "# MCache = %d / %d\n", s.MCacheInuse, s.MCacheSys)
	fmt.Fprintf(w, "# BuckHashSys = %d\n", s.BuckHashSys)
	fmt.Fprintf(w, "# GCSys = %d\n", s.GCSys)
	fmt.Fprintf(w, "# OtherSys = %d\n", s.OtherSys)

	fmt.Fprintf(w, "# NextGC = %d\n", s.NextGC)
	fmt.Fprintf(w, "# PauseNs = %d\n", s.PauseNs)
	fmt.Fprintf(w, "# NumGC = %d\n", s.NumGC)
	fmt.Fprintf(w, "# DebugGC = %v\n", s.DebugGC)

	tw.Flush()
	return b.Flush()
}

// cookies is like Cookies but takes the current time as a parameter.
func (j *Jar) cookies(u *url.URL, now time.Time) (cookies []*http.Cookie) {
	if u.Scheme != "http" && u.Scheme != "https" {
		return cookies
	}
	host, err := canonicalHost(u.Host)
	if err != nil {
		return cookies
	}
	key := jarKey(host, j.psList)

	j.mu.Lock()
	defer j.mu.Unlock()

	submap := j.entries[key]
	if submap == nil {
		return cookies
	}

	https := u.Scheme == "https"
	path := u.Path
	if path == "" {
		path = "/"
	}

	modified := false
	var selected []entry
	for id, e := range submap {
		if e.Persistent && !e.Expires.After(now) {
			delete(submap, id)
			modified = true
			continue
		}
		if !e.shouldSend(https, host, path) {
			continue
		}
		e.LastAccess = now
		submap[id] = e
		selected = append(selected, e)
		modified = true
	}
	if modified {
		if len(submap) == 0 {
			delete(j.entries, key)
		} else {
			j.entries[key] = submap
		}
	}

	// 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})
	}

	return cookies
}