1 files changed, 75 insertions, 0 deletions
diff --git a/src/cmd/pprof/internal/svg/svg.go b/src/cmd/pprof/internal/svg/svg.go
new file mode 100644
index 000000000..aa65a1a08
--- /dev/null
+++ b/src/cmd/pprof/internal/svg/svg.go
@@ -0,0 +1,75 @@
+// Copyright 2014 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 svg provides tools related to handling of SVG files
+package svg
+
+import (
+	"bytes"
+	"regexp"
+	"strings"
+)
+
+var (
+	viewBox  = regexp.MustCompile(`<svg\s*width="[^"]+"\s*height="[^"]+"\s*viewBox="[^"]+"`)
+	graphId  = regexp.MustCompile(`<g id="graph\d"`)
+	svgClose = regexp.MustCompile(`</svg>`)
+)
+
+// Massage enhances the SVG output from DOT to provide bettern
+// panning inside a web browser. It uses the SVGPan library, which is
+// accessed through the svgPan URL.
+func Massage(in bytes.Buffer, svgPan string) string {
+	svg := string(in.Bytes())
+
+	// Work around for dot bug which misses quoting some ampersands,
+	// resulting on unparsable SVG.
+	svg = strings.Replace(svg, "&;", "&amp;;", -1)
+	if svgPan == "" {
+		return svg
+	}
+
+	//Dot's SVG output is
+	//
+	//    <svg width="___" height="___"
+	//     viewBox="___" xmlns=...>
+	//    <g id="graph0" transform="...">
+	//    ...
+	//    </g>
+	//    </svg>
+	//
+	// Change it to
+	//
+	//    <svg width="100%" height="100%"
+	//     xmlns=...>
+	//    <script xlink:href=" ...$svgpan.. "/>
+
+	//    <g id="viewport" transform="translate(0,0)">
+	//    <g id="graph0" transform="...">
+	//    ...
+	//    </g>
+	//    </g>
+	//    </svg>
+
+	if loc := viewBox.FindStringIndex(svg); loc != nil {
+		svg = svg[:loc[0]] +
+			`<svg width="100%" height="100%"` +
+			svg[loc[1]:]
+	}
+
+	if loc := graphId.FindStringIndex(svg); loc != nil {
+		svg = svg[:loc[0]] +
+			`<script xlink:href="` + svgPan + `"/>` +
+			`<g id="viewport" transform="scale(0.5,0.5) translate(0,0)">` +
+			svg[loc[0]:]
+	}
+
+	if loc := svgClose.FindStringIndex(svg); loc != nil {
+		svg = svg[:loc[0]] +
+			`</g>` +
+			svg[loc[0]:]
+	}
+
+	return svg
+}