cmd/geth, mobile: add memsize to pprof server (#16532)

* cmd/geth, mobile: add memsize to pprof server

This is a temporary change, to be reverted before the next release.

* cmd/geth: fix variable name

vendor/github.com/fjl/memsize/memsizeui/ui.go

@@ -0,0 +1,153 @@
+package memsizeui
+
+import (
+	"bytes"
+	"fmt"
+	"html/template"
+	"net/http"
+	"reflect"
+	"sort"
+	"strings"
+	"sync"
+	"time"
+
+	"github.com/fjl/memsize"
+)
+
+type Handler struct {
+	init     sync.Once
+	mux      http.ServeMux
+	mu       sync.Mutex
+	reports  map[int]Report
+	roots    map[string]interface{}
+	reportID int
+}
+
+type Report struct {
+	ID       int
+	Date     time.Time
+	Duration time.Duration
+	RootName string
+	Sizes    memsize.Sizes
+}
+
+type templateInfo struct {
+	Roots     []string
+	Reports   map[int]Report
+	PathDepth int
+	Data      interface{}
+}
+
+func (ti *templateInfo) Link(path ...string) string {
+	prefix := strings.Repeat("../", ti.PathDepth)
+	return prefix + strings.Join(path, "")
+}
+
+func (h *Handler) Add(name string, v interface{}) {
+	rv := reflect.ValueOf(v)
+	if rv.Kind() != reflect.Ptr || rv.IsNil() {
+		panic("root must be non-nil pointer")
+	}
+	h.mu.Lock()
+	if h.roots == nil {
+		h.roots = make(map[string]interface{})
+	}
+	h.roots[name] = v
+	h.mu.Unlock()
+}
+
+func (h *Handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	h.init.Do(func() {
+		h.reports = make(map[int]Report)
+		h.mux.HandleFunc("/", h.handleRoot)
+		h.mux.HandleFunc("/scan", h.handleScan)
+		h.mux.HandleFunc("/report/", h.handleReport)
+	})
+	h.mux.ServeHTTP(w, r)
+}
+
+func (h *Handler) templateInfo(r *http.Request, data interface{}) *templateInfo {
+	h.mu.Lock()
+	roots := make([]string, 0, len(h.roots))
+	for name := range h.roots {
+		roots = append(roots, name)
+	}
+	h.mu.Unlock()
+	sort.Strings(roots)
+
+	return &templateInfo{
+		Roots:     roots,
+		Reports:   h.reports,
+		PathDepth: strings.Count(r.URL.Path, "/") - 1,
+		Data:      data,
+	}
+}
+
+func (h *Handler) handleRoot(w http.ResponseWriter, r *http.Request) {
+	if r.URL.Path != "/" {
+		http.NotFound(w, r)
+		return
+	}
+	serveHTML(w, rootTemplate, http.StatusOK, h.templateInfo(r, nil))
+}
+
+func (h *Handler) handleScan(w http.ResponseWriter, r *http.Request) {
+	if r.Method != http.MethodPost {
+		http.Error(w, "invalid HTTP method, want POST", http.StatusMethodNotAllowed)
+		return
+	}
+	ti := h.templateInfo(r, "Unknown root")
+	id, ok := h.scan(r.URL.Query().Get("root"))
+	if !ok {
+		serveHTML(w, notFoundTemplate, http.StatusNotFound, ti)
+		return
+	}
+	w.Header().Add("Location", ti.Link(fmt.Sprintf("report/%d", id)))
+	w.WriteHeader(http.StatusSeeOther)
+}
+
+func (h *Handler) handleReport(w http.ResponseWriter, r *http.Request) {
+	var id int
+	fmt.Sscan(strings.TrimPrefix(r.URL.Path, "/report/"), &id)
+	h.mu.Lock()
+	report, ok := h.reports[id]
+	h.mu.Unlock()
+
+	if !ok {
+		serveHTML(w, notFoundTemplate, http.StatusNotFound, h.templateInfo(r, "Report not found"))
+	} else {
+		serveHTML(w, reportTemplate, http.StatusOK, h.templateInfo(r, report))
+	}
+}
+
+func (h *Handler) scan(root string) (int, bool) {
+	h.mu.Lock()
+	defer h.mu.Unlock()
+
+	val, ok := h.roots[root]
+	if !ok {
+		return 0, false
+	}
+	id := h.reportID
+	start := time.Now()
+	sizes := memsize.Scan(val)
+	h.reports[id] = Report{
+		ID:       id,
+		RootName: root,
+		Date:     start.Truncate(1 * time.Second),
+		Duration: time.Since(start),
+		Sizes:    sizes,
+	}
+	h.reportID++
+	return id, true
+}
+
+func serveHTML(w http.ResponseWriter, tpl *template.Template, status int, ti *templateInfo) {
+	w.Header().Set("content-type", "text/html")
+	var buf bytes.Buffer
+	if err := tpl.Execute(&buf, ti); err != nil {
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+		return
+	}
+	buf.WriteTo(w)
+}