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1// Copyright 2014 Google Inc. All Rights Reserved.
2//
3// Licensed under the Apache License, Version 2.0 (the "License");
4// you may not use this file except in compliance with the License.
5// You may obtain a copy of the License at
6//
7//     http://www.apache.org/licenses/LICENSE-2.0
8//
9// Unless required by applicable law or agreed to in writing, software
10// distributed under the License is distributed on an "AS IS" BASIS,
11// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12// See the License for the specific language governing permissions and
13// limitations under the License.
14
15package driver
16
17import (
18	"regexp"
19	"strings"
20
21	"github.com/google/pprof/third_party/svgpan"
22)
23
24var (
25	viewBox  = regexp.MustCompile(`<svg\s*width="[^"]+"\s*height="[^"]+"\s*viewBox="[^"]+"`)
26	graphID  = regexp.MustCompile(`<g id="graph\d"`)
27	svgClose = regexp.MustCompile(`</svg>`)
28)
29
30// massageSVG enhances the SVG output from DOT to provide better
31// panning inside a web browser. It uses the svgpan library, which is
32// embedded into the svgpan.JSSource variable.
33func massageSVG(svg string) string {
34	// Work around for dot bug which misses quoting some ampersands,
35	// resulting on unparsable SVG.
36	svg = strings.Replace(svg, "&;", "&amp;;", -1)
37
38	// Dot's SVG output is
39	//
40	//    <svg width="___" height="___"
41	//     viewBox="___" xmlns=...>
42	//    <g id="graph0" transform="...">
43	//    ...
44	//    </g>
45	//    </svg>
46	//
47	// Change it to
48	//
49	//    <svg width="100%" height="100%"
50	//     xmlns=...>
51
52	//    <script type="text/ecmascript"><![CDATA[` ..$(svgpan.JSSource)... `]]></script>`
53	//    <g id="viewport" transform="translate(0,0)">
54	//    <g id="graph0" transform="...">
55	//    ...
56	//    </g>
57	//    </g>
58	//    </svg>
59
60	if loc := viewBox.FindStringIndex(svg); loc != nil {
61		svg = svg[:loc[0]] +
62			`<svg width="100%" height="100%"` +
63			svg[loc[1]:]
64	}
65
66	if loc := graphID.FindStringIndex(svg); loc != nil {
67		svg = svg[:loc[0]] +
68			`<script type="text/ecmascript"><![CDATA[` + svgpan.JSSource + `]]></script>` +
69			`<g id="viewport" transform="scale(0.5,0.5) translate(0,0)">` +
70			svg[loc[0]:]
71	}
72
73	if loc := svgClose.FindStringIndex(svg); loc != nil {
74		svg = svg[:loc[0]] +
75			`</g>` +
76			svg[loc[0]:]
77	}
78
79	return svg
80}
81