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