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Source file src/cmd/cover/html.go

Documentation: cmd/cover

  // Copyright 2013 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 main
  
  import (
  	"bufio"
  	"bytes"
  	"cmd/internal/browser"
  	"fmt"
  	"html/template"
  	"io"
  	"io/ioutil"
  	"math"
  	"os"
  	"path/filepath"
  )
  
  // htmlOutput reads the profile data from profile and generates an HTML
  // coverage report, writing it to outfile. If outfile is empty,
  // it writes the report to a temporary file and opens it in a web browser.
  func htmlOutput(profile, outfile string) error {
  	profiles, err := ParseProfiles(profile)
  	if err != nil {
  		return err
  	}
  
  	var d templateData
  
  	for _, profile := range profiles {
  		fn := profile.FileName
  		if profile.Mode == "set" {
  			d.Set = true
  		}
  		file, err := findFile(fn)
  		if err != nil {
  			return err
  		}
  		src, err := ioutil.ReadFile(file)
  		if err != nil {
  			return fmt.Errorf("can't read %q: %v", fn, err)
  		}
  		var buf bytes.Buffer
  		err = htmlGen(&buf, src, profile.Boundaries(src))
  		if err != nil {
  			return err
  		}
  		d.Files = append(d.Files, &templateFile{
  			Name:     fn,
  			Body:     template.HTML(buf.String()),
  			Coverage: percentCovered(profile),
  		})
  	}
  
  	var out *os.File
  	if outfile == "" {
  		var dir string
  		dir, err = ioutil.TempDir("", "cover")
  		if err != nil {
  			return err
  		}
  		out, err = os.Create(filepath.Join(dir, "coverage.html"))
  	} else {
  		out, err = os.Create(outfile)
  	}
  	if err != nil {
  		return err
  	}
  	err = htmlTemplate.Execute(out, d)
  	if err2 := out.Close(); err == nil {
  		err = err2
  	}
  	if err != nil {
  		return err
  	}
  
  	if outfile == "" {
  		if !browser.Open("file://" + out.Name()) {
  			fmt.Fprintf(os.Stderr, "HTML output written to %s\n", out.Name())
  		}
  	}
  
  	return nil
  }
  
  // percentCovered returns, as a percentage, the fraction of the statements in
  // the profile covered by the test run.
  // In effect, it reports the coverage of a given source file.
  func percentCovered(p *Profile) float64 {
  	var total, covered int64
  	for _, b := range p.Blocks {
  		total += int64(b.NumStmt)
  		if b.Count > 0 {
  			covered += int64(b.NumStmt)
  		}
  	}
  	if total == 0 {
  		return 0
  	}
  	return float64(covered) / float64(total) * 100
  }
  
  // htmlGen generates an HTML coverage report with the provided filename,
  // source code, and tokens, and writes it to the given Writer.
  func htmlGen(w io.Writer, src []byte, boundaries []Boundary) error {
  	dst := bufio.NewWriter(w)
  	for i := range src {
  		for len(boundaries) > 0 && boundaries[0].Offset == i {
  			b := boundaries[0]
  			if b.Start {
  				n := 0
  				if b.Count > 0 {
  					n = int(math.Floor(b.Norm*9)) + 1
  				}
  				fmt.Fprintf(dst, `<span class="cov%v" title="%v">`, n, b.Count)
  			} else {
  				dst.WriteString("</span>")
  			}
  			boundaries = boundaries[1:]
  		}
  		switch b := src[i]; b {
  		case '>':
  			dst.WriteString("&gt;")
  		case '<':
  			dst.WriteString("&lt;")
  		case '&':
  			dst.WriteString("&amp;")
  		case '\t':
  			dst.WriteString("        ")
  		default:
  			dst.WriteByte(b)
  		}
  	}
  	return dst.Flush()
  }
  
  // rgb returns an rgb value for the specified coverage value
  // between 0 (no coverage) and 10 (max coverage).
  func rgb(n int) string {
  	if n == 0 {
  		return "rgb(192, 0, 0)" // Red
  	}
  	// Gradient from gray to green.
  	r := 128 - 12*(n-1)
  	g := 128 + 12*(n-1)
  	b := 128 + 3*(n-1)
  	return fmt.Sprintf("rgb(%v, %v, %v)", r, g, b)
  }
  
  // colors generates the CSS rules for coverage colors.
  func colors() template.CSS {
  	var buf bytes.Buffer
  	for i := 0; i < 11; i++ {
  		fmt.Fprintf(&buf, ".cov%v { color: %v }\n", i, rgb(i))
  	}
  	return template.CSS(buf.String())
  }
  
  var htmlTemplate = template.Must(template.New("html").Funcs(template.FuncMap{
  	"colors": colors,
  }).Parse(tmplHTML))
  
  type templateData struct {
  	Files []*templateFile
  	Set   bool
  }
  
  type templateFile struct {
  	Name     string
  	Body     template.HTML
  	Coverage float64
  }
  
  const tmplHTML = `
  <!DOCTYPE html>
  <html>
  	<head>
  		<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
  		<style>
  			body {
  				background: black;
  				color: rgb(80, 80, 80);
  			}
  			body, pre, #legend span {
  				font-family: Menlo, monospace;
  				font-weight: bold;
  			}
  			#topbar {
  				background: black;
  				position: fixed;
  				top: 0; left: 0; right: 0;
  				height: 42px;
  				border-bottom: 1px solid rgb(80, 80, 80);
  			}
  			#content {
  				margin-top: 50px;
  			}
  			#nav, #legend {
  				float: left;
  				margin-left: 10px;
  			}
  			#legend {
  				margin-top: 12px;
  			}
  			#nav {
  				margin-top: 10px;
  			}
  			#legend span {
  				margin: 0 5px;
  			}
  			{{colors}}
  		</style>
  	</head>
  	<body>
  		<div id="topbar">
  			<div id="nav">
  				<select id="files">
  				{{range $i, $f := .Files}}
  				<option value="file{{$i}}">{{$f.Name}} ({{printf "%.1f" $f.Coverage}}%)</option>
  				{{end}}
  				</select>
  			</div>
  			<div id="legend">
  				<span>not tracked</span>
  			{{if .Set}}
  				<span class="cov0">not covered</span>
  				<span class="cov8">covered</span>
  			{{else}}
  				<span class="cov0">no coverage</span>
  				<span class="cov1">low coverage</span>
  				<span class="cov2">*</span>
  				<span class="cov3">*</span>
  				<span class="cov4">*</span>
  				<span class="cov5">*</span>
  				<span class="cov6">*</span>
  				<span class="cov7">*</span>
  				<span class="cov8">*</span>
  				<span class="cov9">*</span>
  				<span class="cov10">high coverage</span>
  			{{end}}
  			</div>
  		</div>
  		<div id="content">
  		{{range $i, $f := .Files}}
  		<pre class="file" id="file{{$i}}" style="display: none">{{$f.Body}}</pre>
  		{{end}}
  		</div>
  	</body>
  	<script>
  	(function() {
  		var files = document.getElementById('files');
  		var visible;
  		files.addEventListener('change', onChange, false);
  		function select(part) {
  			if (visible)
  				visible.style.display = 'none';
  			visible = document.getElementById(part);
  			if (!visible)
  				return;
  			files.value = part;
  			visible.style.display = 'block';
  			location.hash = part;
  		}
  		function onChange() {
  			select(files.value);
  			window.scrollTo(0, 0);
  		}
  		if (location.hash != "") {
  			select(location.hash.substr(1));
  		}
  		if (!visible) {
  			select("file0");
  		}
  	})();
  	</script>
  </html>
  `
  

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