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// 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.
// This file implements the visitor that computes the (line, column)-(line-column) range for each function.
package main
import (
"bufio"
"bytes"
"encoding/json"
"errors"
"fmt"
"go/ast"
"go/parser"
"go/token"
"io"
"os"
"os/exec"
"path"
"path/filepath"
"runtime"
"strings"
"text/tabwriter"
)
// funcOutput takes two file names as arguments, a coverage profile to read as input and an output
// file to write ("" means to write to standard output). The function reads the profile and produces
// as output the coverage data broken down by function, like this:
//
// fmt/format.go:30: init 100.0%
// fmt/format.go:57: clearflags 100.0%
// ...
// fmt/scan.go:1046: doScan 100.0%
// fmt/scan.go:1075: advance 96.2%
// fmt/scan.go:1119: doScanf 96.8%
// total: (statements) 91.9%
func funcOutput(profile, outputFile string) error {
profiles, err := ParseProfiles(profile)
if err != nil {
return err
}
dirs, err := findPkgs(profiles)
if err != nil {
return err
}
var out *bufio.Writer
if outputFile == "" {
out = bufio.NewWriter(os.Stdout)
} else {
fd, err := os.Create(outputFile)
if err != nil {
return err
}
defer fd.Close()
out = bufio.NewWriter(fd)
}
defer out.Flush()
tabber := tabwriter.NewWriter(out, 1, 8, 1, '\t', 0)
defer tabber.Flush()
var total, covered int64
for _, profile := range profiles {
fn := profile.FileName
file, err := findFile(dirs, fn)
if err != nil {
return err
}
funcs, err := findFuncs(file)
if err != nil {
return err
}
// Now match up functions and profile blocks.
for _, f := range funcs {
c, t := f.coverage(profile)
fmt.Fprintf(tabber, "%s:%d:\t%s\t%.1f%%\n", fn, f.startLine, f.name, percent(c, t))
total += t
covered += c
}
}
fmt.Fprintf(tabber, "total:\t(statements)\t%.1f%%\n", percent(covered, total))
return nil
}
// findFuncs parses the file and returns a slice of FuncExtent descriptors.
func findFuncs(name string) ([]*FuncExtent, error) {
fset := token.NewFileSet()
parsedFile, err := parser.ParseFile(fset, name, nil, 0)
if err != nil {
return nil, err
}
visitor := &FuncVisitor{
fset: fset,
name: name,
astFile: parsedFile,
}
ast.Walk(visitor, visitor.astFile)
return visitor.funcs, nil
}
// FuncExtent describes a function's extent in the source by file and position.
type FuncExtent struct {
name string
startLine int
startCol int
endLine int
endCol int
}
// FuncVisitor implements the visitor that builds the function position list for a file.
type FuncVisitor struct {
fset *token.FileSet
name string // Name of file.
astFile *ast.File
funcs []*FuncExtent
}
// Visit implements the ast.Visitor interface.
func (v *FuncVisitor) Visit(node ast.Node) ast.Visitor {
switch n := node.(type) {
case *ast.FuncDecl:
if n.Body == nil {
// Do not count declarations of assembly functions.
break
}
start := v.fset.Position(n.Pos())
end := v.fset.Position(n.End())
fe := &FuncExtent{
name: n.Name.Name,
startLine: start.Line,
startCol: start.Column,
endLine: end.Line,
endCol: end.Column,
}
v.funcs = append(v.funcs, fe)
}
return v
}
// coverage returns the fraction of the statements in the function that were covered, as a numerator and denominator.
func (f *FuncExtent) coverage(profile *Profile) (num, den int64) {
// We could avoid making this n^2 overall by doing a single scan and annotating the functions,
// but the sizes of the data structures is never very large and the scan is almost instantaneous.
var covered, total int64
// The blocks are sorted, so we can stop counting as soon as we reach the end of the relevant block.
for _, b := range profile.Blocks {
if b.StartLine > f.endLine || (b.StartLine == f.endLine && b.StartCol >= f.endCol) {
// Past the end of the function.
break
}
if b.EndLine < f.startLine || (b.EndLine == f.startLine && b.EndCol <= f.startCol) {
// Before the beginning of the function
continue
}
total += int64(b.NumStmt)
if b.Count > 0 {
covered += int64(b.NumStmt)
}
}
return covered, total
}
// Pkg describes a single package, compatible with the JSON output from 'go list'; see 'go help list'.
type Pkg struct {
ImportPath string
Dir string
Error *struct {
Err string
}
}
func findPkgs(profiles []*Profile) (map[string]*Pkg, error) {
// Run go list to find the location of every package we care about.
pkgs := make(map[string]*Pkg)
var list []string
for _, profile := range profiles {
if strings.HasPrefix(profile.FileName, ".") || filepath.IsAbs(profile.FileName) {
// Relative or absolute path.
continue
}
pkg := path.Dir(profile.FileName)
if _, ok := pkgs[pkg]; !ok {
pkgs[pkg] = nil
list = append(list, pkg)
}
}
// Note: usually run as "go tool cover" in which case $GOROOT is set,
// in which case runtime.GOROOT() does exactly what we want.
goTool := filepath.Join(runtime.GOROOT(), "bin/go")
cmd := exec.Command(goTool, append([]string{"list", "-e", "-json"}, list...)...)
var stderr bytes.Buffer
cmd.Stderr = &stderr
stdout, err := cmd.Output()
if err != nil {
return nil, fmt.Errorf("cannot run go list: %v\n%s", err, stderr.Bytes())
}
dec := json.NewDecoder(bytes.NewReader(stdout))
for {
var pkg Pkg
err := dec.Decode(&pkg)
if err == io.EOF {
break
}
if err != nil {
return nil, fmt.Errorf("decoding go list json: %v", err)
}
pkgs[pkg.ImportPath] = &pkg
}
return pkgs, nil
}
// findFile finds the location of the named file in GOROOT, GOPATH etc.
func findFile(pkgs map[string]*Pkg, file string) (string, error) {
if strings.HasPrefix(file, ".") || filepath.IsAbs(file) {
// Relative or absolute path.
return file, nil
}
pkg := pkgs[path.Dir(file)]
if pkg != nil {
if pkg.Dir != "" {
return filepath.Join(pkg.Dir, path.Base(file)), nil
}
if pkg.Error != nil {
return "", errors.New(pkg.Error.Err)
}
}
return "", fmt.Errorf("did not find package for %s in go list output", file)
}
func percent(covered, total int64) float64 {
if total == 0 {
total = 1 // Avoid zero denominator.
}
return 100.0 * float64(covered) / float64(total)
}