Adding upstream version 1.22.1.upstream/1.22.1

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 86 insertions, 0 deletions

diff --git a/src/internal/trace/traceviewer/histogram.go b/src/internal/trace/traceviewer/histogram.go
new file mode 100644
index 0000000..d4c8749
--- /dev/null
+++ b/src/internal/trace/traceviewer/histogram.go
@@ -0,0 +1,86 @@
+// Copyright 2023 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 traceviewer
+
+import (
+	"fmt"
+	"html/template"
+	"math"
+	"strings"
+	"time"
+)
+
+// TimeHistogram is an high-dynamic-range histogram for durations.
+type TimeHistogram struct {
+	Count                int
+	Buckets              []int
+	MinBucket, MaxBucket int
+}
+
+// Five buckets for every power of 10.
+var logDiv = math.Log(math.Pow(10, 1.0/5))
+
+// Add adds a single sample to the histogram.
+func (h *TimeHistogram) Add(d time.Duration) {
+	var bucket int
+	if d > 0 {
+		bucket = int(math.Log(float64(d)) / logDiv)
+	}
+	if len(h.Buckets) <= bucket {
+		h.Buckets = append(h.Buckets, make([]int, bucket-len(h.Buckets)+1)...)
+		h.Buckets = h.Buckets[:cap(h.Buckets)]
+	}
+	h.Buckets[bucket]++
+	if bucket < h.MinBucket || h.MaxBucket == 0 {
+		h.MinBucket = bucket
+	}
+	if bucket > h.MaxBucket {
+		h.MaxBucket = bucket
+	}
+	h.Count++
+}
+
+// BucketMin returns the minimum duration value for a provided bucket.
+func (h *TimeHistogram) BucketMin(bucket int) time.Duration {
+	return time.Duration(math.Exp(float64(bucket) * logDiv))
+}
+
+// ToHTML renders the histogram as HTML.
+func (h *TimeHistogram) ToHTML(urlmaker func(min, max time.Duration) string) template.HTML {
+	if h == nil || h.Count == 0 {
+		return template.HTML("")
+	}
+
+	const barWidth = 400
+
+	maxCount := 0
+	for _, count := range h.Buckets {
+		if count > maxCount {
+			maxCount = count
+		}
+	}
+
+	w := new(strings.Builder)
+	fmt.Fprintf(w, `<table>`)
+	for i := h.MinBucket; i <= h.MaxBucket; i++ {
+		// Tick label.
+		if h.Buckets[i] > 0 {
+			fmt.Fprintf(w, `<tr><td class="histoTime" align="right"><a href=%s>%s</a></td>`, urlmaker(h.BucketMin(i), h.BucketMin(i+1)), h.BucketMin(i))
+		} else {
+			fmt.Fprintf(w, `<tr><td class="histoTime" align="right">%s</td>`, h.BucketMin(i))
+		}
+		// Bucket bar.
+		width := h.Buckets[i] * barWidth / maxCount
+		fmt.Fprintf(w, `<td><div style="width:%dpx;background:blue;position:relative">&nbsp;</div></td>`, width)
+		// Bucket count.
+		fmt.Fprintf(w, `<td align="right"><div style="position:relative">%d</div></td>`, h.Buckets[i])
+		fmt.Fprintf(w, "</tr>\n")
+
+	}
+	// Final tick label.
+	fmt.Fprintf(w, `<tr><td align="right">%s</td></tr>`, h.BucketMin(h.MaxBucket+1))
+	fmt.Fprintf(w, `</table>`)
+	return template.HTML(w.String())
+}