diff options
Diffstat (limited to 'vendor/github.com')
-rw-r--r-- | vendor/github.com/fjl/memsize/LICENSE | 21 | ||||
-rw-r--r-- | vendor/github.com/fjl/memsize/bitmap.go | 119 | ||||
-rw-r--r-- | vendor/github.com/fjl/memsize/doc.go | 16 | ||||
-rw-r--r-- | vendor/github.com/fjl/memsize/memsize.go | 243 | ||||
-rw-r--r-- | vendor/github.com/fjl/memsize/memsizeui/template.go | 106 | ||||
-rw-r--r-- | vendor/github.com/fjl/memsize/memsizeui/ui.go | 153 | ||||
-rw-r--r-- | vendor/github.com/fjl/memsize/runtimefunc.go | 14 | ||||
-rw-r--r-- | vendor/github.com/fjl/memsize/runtimefunc.s | 1 | ||||
-rw-r--r-- | vendor/github.com/fjl/memsize/type.go | 119 |
9 files changed, 792 insertions, 0 deletions
diff --git a/vendor/github.com/fjl/memsize/LICENSE b/vendor/github.com/fjl/memsize/LICENSE new file mode 100644 index 000000000..8b8045641 --- /dev/null +++ b/vendor/github.com/fjl/memsize/LICENSE @@ -0,0 +1,21 @@ +MIT License + +Copyright (c) 2018 Felix Lange + +Permission is hereby granted, free of charge, to any person obtaining a copy +of this software and associated documentation files (the "Software"), to deal +in the Software without restriction, including without limitation the rights +to use, copy, modify, merge, publish, distribute, sublicense, and/or sell +copies of the Software, and to permit persons to whom the Software is +furnished to do so, subject to the following conditions: + +The above copyright notice and this permission notice shall be included in all +copies or substantial portions of the Software. + +THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR +IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, +FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE +AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER +LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, +OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE +SOFTWARE. diff --git a/vendor/github.com/fjl/memsize/bitmap.go b/vendor/github.com/fjl/memsize/bitmap.go new file mode 100644 index 000000000..47799ea8d --- /dev/null +++ b/vendor/github.com/fjl/memsize/bitmap.go @@ -0,0 +1,119 @@ +package memsize + +import ( + "math/bits" +) + +const ( + uintptrBits = 32 << (uint64(^uintptr(0)) >> 63) + uintptrBytes = uintptrBits / 8 + bmBlockRange = 1 * 1024 * 1024 // bytes covered by bmBlock + bmBlockWords = bmBlockRange / uintptrBits +) + +// bitmap is a sparse bitmap. +type bitmap struct { + blocks map[uintptr]*bmBlock +} + +func newBitmap() *bitmap { + return &bitmap{make(map[uintptr]*bmBlock)} +} + +// markRange sets n consecutive bits starting at addr. +func (b *bitmap) markRange(addr, n uintptr) { + for end := addr + n; addr < end; { + block, baddr := b.block(addr) + for i := baddr; i < bmBlockRange && addr < end; i++ { + block.mark(i) + addr++ + } + } +} + +// isMarked returns the value of the bit at the given address. +func (b *bitmap) isMarked(addr uintptr) bool { + block, baddr := b.block(addr) + return block.isMarked(baddr) +} + +// countRange returns the number of set bits in the range (addr,addr+n). +func (b *bitmap) countRange(addr, n uintptr) uintptr { + c := uintptr(0) + for end := addr + n; addr < end; { + block, baddr := b.block(addr) + bend := uintptr(bmBlockRange - 1) + if baddr+(end-addr) < bmBlockRange { + bend = baddr + (end - addr) + } + c += uintptr(block.count(baddr, bend)) + // Move addr to next block. + addr += bmBlockRange - baddr + } + return c +} + +// block finds the block corresponding to the given memory address. +// It also returns the block's starting address. +func (b *bitmap) block(addr uintptr) (*bmBlock, uintptr) { + index := addr / bmBlockRange + block := b.blocks[index] + if block == nil { + block = new(bmBlock) + b.blocks[index] = block + } + return block, addr % bmBlockRange +} + +// size returns the sum of the byte sizes of all blocks. +func (b *bitmap) size() uintptr { + return uintptr(len(b.blocks)) * bmBlockWords * uintptrBytes +} + +// utilization returns the mean percentage of one bits across all blocks. +func (b *bitmap) utilization() float32 { + var avg float32 + for _, block := range b.blocks { + avg += float32(block.count(0, bmBlockRange-1)) / float32(bmBlockRange) + } + return avg / float32(len(b.blocks)) +} + +// bmBlock is a bitmap block. +type bmBlock [bmBlockWords]uintptr + +// mark sets the i'th bit to one. +func (b *bmBlock) mark(i uintptr) { + b[i/uintptrBits] |= 1 << (i % uintptrBits) +} + +// isMarked returns the value of the i'th bit. +func (b *bmBlock) isMarked(i uintptr) bool { + return (b[i/uintptrBits] & (1 << (i % uintptrBits))) != 0 +} + +// count returns the number of set bits in the range (start,end). +func (b *bmBlock) count(start, end uintptr) (count int) { + br := b[start/uintptrBits : end/uintptrBits+1] + for i, w := range br { + if i == 0 { + w &= blockmask(start) + } + if i == len(br)-1 { + w &^= blockmask(end) + } + count += onesCountPtr(w) + } + return count +} + +func blockmask(x uintptr) uintptr { + return ^uintptr(0) << (x % uintptrBits) +} + +func onesCountPtr(x uintptr) int { + if uintptrBits == 64 { + return bits.OnesCount64(uint64(x)) + } + return bits.OnesCount32(uint32(x)) +} diff --git a/vendor/github.com/fjl/memsize/doc.go b/vendor/github.com/fjl/memsize/doc.go new file mode 100644 index 000000000..640cfba5e --- /dev/null +++ b/vendor/github.com/fjl/memsize/doc.go @@ -0,0 +1,16 @@ +/* +Package memsize computes the size of your object graph. + +So you made a spiffy algorithm and it works really well, but geez it's using +way too much memory. Where did it all go? memsize to the rescue! + +To get started, find a value that references all your objects and scan it. +This traverses the graph, counting sizes per type. + + sizes := memsize.Scan(myValue) + fmt.Println(sizes.Total) + +memsize can handle cycles just fine and tracks both private and public struct fields. +Unfortunately function closures cannot be inspected in any way. +*/ +package memsize diff --git a/vendor/github.com/fjl/memsize/memsize.go b/vendor/github.com/fjl/memsize/memsize.go new file mode 100644 index 000000000..2664e87c4 --- /dev/null +++ b/vendor/github.com/fjl/memsize/memsize.go @@ -0,0 +1,243 @@ +package memsize + +import ( + "bytes" + "fmt" + "reflect" + "sort" + "strings" + "text/tabwriter" + "unsafe" +) + +// Scan traverses all objects reachable from v and counts how much memory +// is used per type. The value must be a non-nil pointer to any value. +func Scan(v interface{}) Sizes { + rv := reflect.ValueOf(v) + if rv.Kind() != reflect.Ptr || rv.IsNil() { + panic("value to scan must be non-nil pointer") + } + + stopTheWorld("memsize scan") + defer startTheWorld() + + ctx := newContext() + ctx.scan(invalidAddr, rv, false) + ctx.s.BitmapSize = ctx.seen.size() + ctx.s.BitmapUtilization = ctx.seen.utilization() + return *ctx.s +} + +// Sizes is the result of a scan. +type Sizes struct { + Total uintptr + ByType map[reflect.Type]*TypeSize + // Internal stats (for debugging) + BitmapSize uintptr + BitmapUtilization float32 +} + +type TypeSize struct { + Total uintptr + Count uintptr +} + +func newSizes() *Sizes { + return &Sizes{ByType: make(map[reflect.Type]*TypeSize)} +} + +// Report returns a human-readable report. +func (s Sizes) Report() string { + type typLine struct { + name string + count uintptr + total uintptr + } + tab := []typLine{{"ALL", 0, s.Total}} + for _, typ := range s.ByType { + tab[0].count += typ.Count + } + maxname := 0 + for typ, s := range s.ByType { + line := typLine{typ.String(), s.Count, s.Total} + tab = append(tab, line) + if len(line.name) > maxname { + maxname = len(line.name) + } + } + sort.Slice(tab, func(i, j int) bool { return tab[i].total > tab[j].total }) + + buf := new(bytes.Buffer) + w := tabwriter.NewWriter(buf, 0, 0, 0, ' ', tabwriter.AlignRight) + for _, line := range tab { + namespace := strings.Repeat(" ", maxname-len(line.name)) + fmt.Fprintf(w, "%s%s\t %v\t %s\t\n", line.name, namespace, line.count, HumanSize(line.total)) + } + w.Flush() + return buf.String() +} + +// addValue is called during scan and adds the memory of given object. +func (s *Sizes) addValue(v reflect.Value, size uintptr) { + s.Total += size + rs := s.ByType[v.Type()] + if rs == nil { + rs = new(TypeSize) + s.ByType[v.Type()] = rs + } + rs.Total += size + rs.Count++ +} + +type context struct { + // We track previously scanned objects to prevent infinite loops + // when scanning cycles and to prevent counting objects more than once. + seen *bitmap + tc typCache + s *Sizes +} + +func newContext() *context { + return &context{seen: newBitmap(), tc: make(typCache), s: newSizes()} +} + +// scan walks all objects below v, determining their size. All scan* functions return the +// amount of 'extra' memory (e.g. slice data) that is referenced by the object. +func (c *context) scan(addr address, v reflect.Value, add bool) (extraSize uintptr) { + size := v.Type().Size() + var marked uintptr + if addr.valid() { + marked = c.seen.countRange(uintptr(addr), size) + if marked == size { + return 0 // Skip if we have already seen the whole object. + } + c.seen.markRange(uintptr(addr), size) + } + // fmt.Printf("%v: %v ⮑ (marked %d)\n", addr, v.Type(), marked) + if c.tc.needScan(v.Type()) { + extraSize = c.scanContent(addr, v) + } + // fmt.Printf("%v: %v %d (add %v, size %d, marked %d, extra %d)\n", addr, v.Type(), size+extraSize, add, v.Type().Size(), marked, extraSize) + if add { + size -= marked + size += extraSize + c.s.addValue(v, size) + } + return extraSize +} + +func (c *context) scanContent(addr address, v reflect.Value) uintptr { + switch v.Kind() { + case reflect.Array: + return c.scanArray(addr, v) + case reflect.Chan: + return c.scanChan(v) + case reflect.Func: + // can't do anything here + return 0 + case reflect.Interface: + return c.scanInterface(v) + case reflect.Map: + return c.scanMap(v) + case reflect.Ptr: + if !v.IsNil() { + c.scan(address(v.Pointer()), v.Elem(), true) + } + return 0 + case reflect.Slice: + return c.scanSlice(v) + case reflect.String: + return uintptr(v.Len()) + case reflect.Struct: + return c.scanStruct(addr, v) + default: + unhandledKind(v.Kind()) + return 0 + } +} + +func (c *context) scanChan(v reflect.Value) uintptr { + etyp := v.Type().Elem() + extra := uintptr(0) + if c.tc.needScan(etyp) { + // Scan the channel buffer. This is unsafe but doesn't race because + // the world is stopped during scan. + hchan := unsafe.Pointer(v.Pointer()) + for i := uint(0); i < uint(v.Cap()); i++ { + addr := chanbuf(hchan, i) + elem := reflect.NewAt(etyp, addr).Elem() + extra += c.scanContent(address(addr), elem) + } + } + return uintptr(v.Cap())*etyp.Size() + extra +} + +func (c *context) scanStruct(base address, v reflect.Value) uintptr { + extra := uintptr(0) + for i := 0; i < v.NumField(); i++ { + f := v.Type().Field(i) + if c.tc.needScan(f.Type) { + addr := base.addOffset(f.Offset) + extra += c.scanContent(addr, v.Field(i)) + } + } + return extra +} + +func (c *context) scanArray(addr address, v reflect.Value) uintptr { + esize := v.Type().Elem().Size() + extra := uintptr(0) + for i := 0; i < v.Len(); i++ { + extra += c.scanContent(addr, v.Index(i)) + addr = addr.addOffset(esize) + } + return extra +} + +func (c *context) scanSlice(v reflect.Value) uintptr { + slice := v.Slice(0, v.Cap()) + esize := slice.Type().Elem().Size() + base := slice.Pointer() + // Add size of the unscanned portion of the backing array to extra. + blen := uintptr(slice.Len()) * esize + marked := c.seen.countRange(base, blen) + extra := blen - marked + c.seen.markRange(uintptr(base), blen) + if c.tc.needScan(slice.Type().Elem()) { + // Elements may contain pointers, scan them individually. + addr := address(base) + for i := 0; i < slice.Len(); i++ { + extra += c.scanContent(addr, slice.Index(i)) + addr = addr.addOffset(esize) + } + } + return extra +} + +func (c *context) scanMap(v reflect.Value) uintptr { + var ( + typ = v.Type() + len = uintptr(v.Len()) + extra = uintptr(0) + ) + if c.tc.needScan(typ.Key()) || c.tc.needScan(typ.Elem()) { + for _, k := range v.MapKeys() { + extra += c.scan(invalidAddr, k, false) + extra += c.scan(invalidAddr, v.MapIndex(k), false) + } + } + return len*typ.Key().Size() + len*typ.Elem().Size() + extra +} + +func (c *context) scanInterface(v reflect.Value) uintptr { + elem := v.Elem() + if !elem.IsValid() { + return 0 // nil interface + } + c.scan(invalidAddr, elem, false) + if !c.tc.isPointer(elem.Type()) { + // Account for non-pointer size of the value. + return elem.Type().Size() + } + return 0 +} diff --git a/vendor/github.com/fjl/memsize/memsizeui/template.go b/vendor/github.com/fjl/memsize/memsizeui/template.go new file mode 100644 index 000000000..b60fe6ba5 --- /dev/null +++ b/vendor/github.com/fjl/memsize/memsizeui/template.go @@ -0,0 +1,106 @@ +package memsizeui + +import ( + "html/template" + "strconv" + "sync" + + "github.com/fjl/memsize" +) + +var ( + base *template.Template // the "base" template + baseInitOnce sync.Once +) + +func baseInit() { + base = template.Must(template.New("base").Parse(`<!DOCTYPE html> +<html> + <head> + <meta charset="UTF-8"> + <title>memsize</title> + <style> + body { + font-family: sans-serif; + } + button, .button { + display: inline-block; + font-weight: bold; + color: black; + text-decoration: none; + font-size: inherit; + padding: 3pt; + margin: 3pt; + background-color: #eee; + border: 1px solid #999; + border-radius: 2pt; + } + form.inline { + display: inline-block; + } + </style> + </head> + <body> + {{template "content" .}} + </body> +</html>`)) + + base.Funcs(template.FuncMap{ + "quote": strconv.Quote, + "humansize": memsize.HumanSize, + }) + + template.Must(base.New("rootbuttons").Parse(` +<a class="button" href="{{$.Link ""}}">Overview</a> +{{- range $root := .Roots -}} +<form class="inline" method="POST" action="{{$.Link "scan?root=" $root}}"> + <button type="submit">Scan {{quote $root}}</button> +</form> +{{- end -}}`)) +} + +func contentTemplate(source string) *template.Template { + baseInitOnce.Do(baseInit) + t := template.Must(base.Clone()) + template.Must(t.New("content").Parse(source)) + return t +} + +var rootTemplate = contentTemplate(` +<h1>Memsize</h1> +{{template "rootbuttons" .}} +<hr/> +<h3>Reports</h3> +<ul> + {{range .Reports}} + <li><a href="{{printf "%d" | $.Link "report/"}}">{{quote .RootName}} @ {{.Date}}</a></li> + {{else}} + No reports yet, hit a scan button to create one. + {{end}} +</ul> +`) + +var notFoundTemplate = contentTemplate(` +<h1>{{.Data}}</h1> +{{template "rootbuttons" .}} +`) + +var reportTemplate = contentTemplate(` +{{- $report := .Data -}} +<h1>Memsize Report {{$report.ID}}</h1> +<form method="POST" action="{{$.Link "scan?root=" $report.RootName}}"> + <a class="button" href="{{$.Link ""}}">Overview</a> + <button type="submit">Scan Again</button> +</form> +<pre> +Root: {{quote $report.RootName}} +Date: {{$report.Date}} +Duration: {{$report.Duration}} +Bitmap Size: {{$report.Sizes.BitmapSize | humansize}} +Bitmap Utilization: {{$report.Sizes.BitmapUtilization}} +</pre> +<hr/> +<pre> +{{$report.Sizes.Report}} +</pre> +`) diff --git a/vendor/github.com/fjl/memsize/memsizeui/ui.go b/vendor/github.com/fjl/memsize/memsizeui/ui.go new file mode 100644 index 000000000..c48fc53f7 --- /dev/null +++ b/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) +} diff --git a/vendor/github.com/fjl/memsize/runtimefunc.go b/vendor/github.com/fjl/memsize/runtimefunc.go new file mode 100644 index 000000000..912a3e768 --- /dev/null +++ b/vendor/github.com/fjl/memsize/runtimefunc.go @@ -0,0 +1,14 @@ +package memsize + +import "unsafe" + +var _ = unsafe.Pointer(nil) + +//go:linkname stopTheWorld runtime.stopTheWorld +func stopTheWorld(reason string) + +//go:linkname startTheWorld runtime.startTheWorld +func startTheWorld() + +//go:linkname chanbuf runtime.chanbuf +func chanbuf(ch unsafe.Pointer, i uint) unsafe.Pointer diff --git a/vendor/github.com/fjl/memsize/runtimefunc.s b/vendor/github.com/fjl/memsize/runtimefunc.s new file mode 100644 index 000000000..a091e2fa7 --- /dev/null +++ b/vendor/github.com/fjl/memsize/runtimefunc.s @@ -0,0 +1 @@ +// This file is required to make stub function declarations work. diff --git a/vendor/github.com/fjl/memsize/type.go b/vendor/github.com/fjl/memsize/type.go new file mode 100644 index 000000000..5d6f59e9f --- /dev/null +++ b/vendor/github.com/fjl/memsize/type.go @@ -0,0 +1,119 @@ +package memsize + +import ( + "fmt" + "reflect" +) + +// address is a memory location. +// +// Code dealing with uintptr is oblivious to the zero address. +// Code dealing with address is not: it treats the zero address +// as invalid. Offsetting an invalid address doesn't do anything. +// +// This distinction is useful because there are objects that we can't +// get the pointer to. +type address uintptr + +const invalidAddr = address(0) + +func (a address) valid() bool { + return a != 0 +} + +func (a address) addOffset(off uintptr) address { + if !a.valid() { + return invalidAddr + } + return a + address(off) +} + +func (a address) String() string { + if uintptrBits == 32 { + return fmt.Sprintf("%#0.8x", uintptr(a)) + } + return fmt.Sprintf("%#0.16x", uintptr(a)) +} + +type typCache map[reflect.Type]typInfo + +type typInfo struct { + isPointer bool + needScan bool +} + +// isPointer returns true for pointer-ish values. The notion of +// pointer includes everything but plain values, i.e. slices, maps +// channels, interfaces are 'pointer', too. +func (tc *typCache) isPointer(typ reflect.Type) bool { + return tc.info(typ).isPointer +} + +// needScan reports whether a value of the type needs to be scanned +// recursively because it may contain pointers. +func (tc *typCache) needScan(typ reflect.Type) bool { + return tc.info(typ).needScan +} + +func (tc *typCache) info(typ reflect.Type) typInfo { + info, found := (*tc)[typ] + switch { + case found: + return info + case isPointer(typ): + info = typInfo{true, true} + default: + info = typInfo{false, tc.checkNeedScan(typ)} + } + (*tc)[typ] = info + return info +} + +func (tc *typCache) checkNeedScan(typ reflect.Type) bool { + switch k := typ.Kind(); k { + case reflect.Struct: + // Structs don't need scan if none of their fields need it. + for i := 0; i < typ.NumField(); i++ { + if tc.needScan(typ.Field(i).Type) { + return true + } + } + case reflect.Array: + // Arrays don't need scan if their element type doesn't. + return tc.needScan(typ.Elem()) + } + return false +} + +func isPointer(typ reflect.Type) bool { + k := typ.Kind() + switch { + case k <= reflect.Complex128: + return false + case k == reflect.Array: + return false + case k >= reflect.Chan && k <= reflect.String: + return true + case k == reflect.Struct || k == reflect.UnsafePointer: + return false + default: + unhandledKind(k) + return false + } +} + +func unhandledKind(k reflect.Kind) { + panic("unhandled kind " + k.String()) +} + +// HumanSize formats the given number of bytes as a readable string. +func HumanSize(bytes uintptr) string { + switch { + case bytes < 1024: + return fmt.Sprintf("%d B", bytes) + case bytes < 1024*1024: + return fmt.Sprintf("%.3f KB", float64(bytes)/1024) + default: + return fmt.Sprintf("%.3f MB", float64(bytes)/1024/1024) + } +} |