Converts Go profile from package paths to filepaths

absolutecover.go

package main

import (
	"bufio"
	"bytes"
	"fmt"
	"io"
	"io/ioutil"
	"os"
	"path"
	"path/filepath"
	"sort"
	"strings"

	"golang.org/x/tools/go/packages"
)

func main() {
	var input io.Reader = os.Stdin
	if len(os.Args) > 1 {
		var err error
		input, err = os.Open(os.Args[1])
		if err != nil {
			fmt.Fprintln(os.Stderr, err)
			os.Exit(1)
		}
	}

	coverFile, err := ioutil.ReadAll(input)
	if err != nil {
		fmt.Fprintln(os.Stderr, err)
		os.Exit(1)
	}

	coveredPackages := map[string]struct{}{}

	scanner := bufio.NewScanner(bytes.NewReader(coverFile))
	for scanner.Scan() {
		line := scanner.Text()
		tokens := strings.SplitN(line, ":", 2)
		if len(tokens) <= 1 {
			continue
		}
		if tokens[0] == "mode" {
			continue
		}
		coveredPackages[path.Dir(tokens[0])] = struct{}{}
	}

	sortedPackages := []string{}
	for coveredPackage := range coveredPackages {
		sortedPackages = append(sortedPackages, coveredPackage)
	}
	sort.Strings(sortedPackages)

	loadedPackages, err := packages.Load(&packages.Config{
		Mode:  packages.LoadFiles,
		Tests: true,
	}, sortedPackages...)

	if err != nil {
		fmt.Fprintf(os.Stderr, "failed to load packages: %v", err)
	}

	packagePath := map[string]string{}
	for _, pkg := range loadedPackages {
		if len(pkg.GoFiles) > 0 {
			packagePath[pkg.ID] = filepath.Dir(pkg.GoFiles[0])
		}
	}

	scanner = bufio.NewScanner(bytes.NewReader(coverFile))
	for scanner.Scan() {
		line := scanner.Text()
		tokens := strings.SplitN(line, ":", 2)
		if len(tokens) <= 1 {
			fmt.Println(line)
			continue
		}
		if tokens[0] == "mode" {
			fmt.Println(line)
			continue
		}

		pkgname := path.Dir(tokens[0])
		file := path.Base(tokens[0])

		pkgpath, ok := packagePath[pkgname]
		if !ok {
			fmt.Println(line)
			continue
		}

		fmt.Println(filepath.Join(pkgpath, file) + ":" + tokens[1])
	}
}