1// Copyright 2013 The Go Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style
3// license that can be found in the LICENSE file.
4
5package main
6
7import (
8	"bufio"
9	"bytes"
10	"cmd/internal/browser"
11	"fmt"
12	"html/template"
13	"io"
14	"math"
15	"os"
16	"path/filepath"
17	"strings"
18
19	"golang.org/x/tools/cover"
20)
21
22// htmlOutput reads the profile data from profile and generates an HTML
23// coverage report, writing it to outfile. If outfile is empty,
24// it writes the report to a temporary file and opens it in a web browser.
25func htmlOutput(profile, outfile string) error {
26	profiles, err := cover.ParseProfiles(profile)
27	if err != nil {
28		return err
29	}
30
31	var d templateData
32
33	dirs, err := findPkgs(profiles)
34	if err != nil {
35		return err
36	}
37
38	for _, profile := range profiles {
39		fn := profile.FileName
40		if profile.Mode == "set" {
41			d.Set = true
42		}
43		file, err := findFile(dirs, fn)
44		if err != nil {
45			return err
46		}
47		src, err := os.ReadFile(file)
48		if err != nil {
49			return fmt.Errorf("can't read %q: %v", fn, err)
50		}
51		var buf strings.Builder
52		err = htmlGen(&buf, src, profile.Boundaries(src))
53		if err != nil {
54			return err
55		}
56		d.Files = append(d.Files, &templateFile{
57			Name:     fn,
58			Body:     template.HTML(buf.String()),
59			Coverage: percentCovered(profile),
60		})
61	}
62
63	var out *os.File
64	if outfile == "" {
65		var dir string
66		dir, err = os.MkdirTemp("", "cover")
67		if err != nil {
68			return err
69		}
70		out, err = os.Create(filepath.Join(dir, "coverage.html"))
71	} else {
72		out, err = os.Create(outfile)
73	}
74	if err != nil {
75		return err
76	}
77	err = htmlTemplate.Execute(out, d)
78	if err2 := out.Close(); err == nil {
79		err = err2
80	}
81	if err != nil {
82		return err
83	}
84
85	if outfile == "" {
86		if !browser.Open("file://" + out.Name()) {
87			fmt.Fprintf(os.Stderr, "HTML output written to %s\n", out.Name())
88		}
89	}
90
91	return nil
92}
93
94// percentCovered returns, as a percentage, the fraction of the statements in
95// the profile covered by the test run.
96// In effect, it reports the coverage of a given source file.
97func percentCovered(p *cover.Profile) float64 {
98	var total, covered int64
99	for _, b := range p.Blocks {
100		total += int64(b.NumStmt)
101		if b.Count > 0 {
102			covered += int64(b.NumStmt)
103		}
104	}
105	if total == 0 {
106		return 0
107	}
108	return float64(covered) / float64(total) * 100
109}
110
111// htmlGen generates an HTML coverage report with the provided filename,
112// source code, and tokens, and writes it to the given Writer.
113func htmlGen(w io.Writer, src []byte, boundaries []cover.Boundary) error {
114	dst := bufio.NewWriter(w)
115	for i := range src {
116		for len(boundaries) > 0 && boundaries[0].Offset == i {
117			b := boundaries[0]
118			if b.Start {
119				n := 0
120				if b.Count > 0 {
121					n = int(math.Floor(b.Norm*9)) + 1
122				}
123				fmt.Fprintf(dst, `<span class="cov%v" title="%v">`, n, b.Count)
124			} else {
125				dst.WriteString("</span>")
126			}
127			boundaries = boundaries[1:]
128		}
129		switch b := src[i]; b {
130		case '>':
131			dst.WriteString("&gt;")
132		case '<':
133			dst.WriteString("&lt;")
134		case '&':
135			dst.WriteString("&amp;")
136		case '\t':
137			dst.WriteString("        ")
138		default:
139			dst.WriteByte(b)
140		}
141	}
142	return dst.Flush()
143}
144
145// rgb returns an rgb value for the specified coverage value
146// between 0 (no coverage) and 10 (max coverage).
147func rgb(n int) string {
148	if n == 0 {
149		return "rgb(192, 0, 0)" // Red
150	}
151	// Gradient from gray to green.
152	r := 128 - 12*(n-1)
153	g := 128 + 12*(n-1)
154	b := 128 + 3*(n-1)
155	return fmt.Sprintf("rgb(%v, %v, %v)", r, g, b)
156}
157
158// colors generates the CSS rules for coverage colors.
159func colors() template.CSS {
160	var buf bytes.Buffer
161	for i := 0; i < 11; i++ {
162		fmt.Fprintf(&buf, ".cov%v { color: %v }\n", i, rgb(i))
163	}
164	return template.CSS(buf.String())
165}
166
167var htmlTemplate = template.Must(template.New("html").Funcs(template.FuncMap{
168	"colors": colors,
169}).Parse(tmplHTML))
170
171type templateData struct {
172	Files []*templateFile
173	Set   bool
174}
175
176// PackageName returns a name for the package being shown.
177// It does this by choosing the penultimate element of the path
178// name, so foo.bar/baz/foo.go chooses 'baz'. This is cheap
179// and easy, avoids parsing the Go file, and gets a better answer
180// for package main. It returns the empty string if there is
181// a problem.
182func (td templateData) PackageName() string {
183	if len(td.Files) == 0 {
184		return ""
185	}
186	fileName := td.Files[0].Name
187	elems := strings.Split(fileName, "/") // Package path is always slash-separated.
188	// Return the penultimate non-empty element.
189	for i := len(elems) - 2; i >= 0; i-- {
190		if elems[i] != "" {
191			return elems[i]
192		}
193	}
194	return ""
195}
196
197type templateFile struct {
198	Name     string
199	Body     template.HTML
200	Coverage float64
201}
202
203const tmplHTML = `
204<!DOCTYPE html>
205<html>
206	<head>
207		<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
208		<title>{{$pkg := .PackageName}}{{if $pkg}}{{$pkg}}: {{end}}Go Coverage Report</title>
209		<style>
210			body {
211				background: black;
212				color: rgb(80, 80, 80);
213			}
214			body, pre, #legend span {
215				font-family: Menlo, monospace;
216				font-weight: bold;
217			}
218			#topbar {
219				background: black;
220				position: fixed;
221				top: 0; left: 0; right: 0;
222				height: 42px;
223				border-bottom: 1px solid rgb(80, 80, 80);
224			}
225			#content {
226				margin-top: 50px;
227			}
228			#nav, #legend {
229				float: left;
230				margin-left: 10px;
231			}
232			#legend {
233				margin-top: 12px;
234			}
235			#nav {
236				margin-top: 10px;
237			}
238			#legend span {
239				margin: 0 5px;
240			}
241			{{colors}}
242		</style>
243	</head>
244	<body>
245		<div id="topbar">
246			<div id="nav">
247				<select id="files">
248				{{range $i, $f := .Files}}
249				<option value="file{{$i}}">{{$f.Name}} ({{printf "%.1f" $f.Coverage}}%)</option>
250				{{end}}
251				</select>
252			</div>
253			<div id="legend">
254				<span>not tracked</span>
255			{{if .Set}}
256				<span class="cov0">not covered</span>
257				<span class="cov8">covered</span>
258			{{else}}
259				<span class="cov0">no coverage</span>
260				<span class="cov1">low coverage</span>
261				<span class="cov2">*</span>
262				<span class="cov3">*</span>
263				<span class="cov4">*</span>
264				<span class="cov5">*</span>
265				<span class="cov6">*</span>
266				<span class="cov7">*</span>
267				<span class="cov8">*</span>
268				<span class="cov9">*</span>
269				<span class="cov10">high coverage</span>
270			{{end}}
271			</div>
272		</div>
273		<div id="content">
274		{{range $i, $f := .Files}}
275		<pre class="file" id="file{{$i}}" style="display: none">{{$f.Body}}</pre>
276		{{end}}
277		</div>
278	</body>
279	<script>
280	(function() {
281		var files = document.getElementById('files');
282		var visible;
283		files.addEventListener('change', onChange, false);
284		function select(part) {
285			if (visible)
286				visible.style.display = 'none';
287			visible = document.getElementById(part);
288			if (!visible)
289				return;
290			files.value = part;
291			visible.style.display = 'block';
292			location.hash = part;
293		}
294		function onChange() {
295			select(files.value);
296			window.scrollTo(0, 0);
297		}
298		if (location.hash != "") {
299			select(location.hash.substr(1));
300		}
301		if (!visible) {
302			select("file0");
303		}
304	})();
305	</script>
306</html>
307`
308