+// 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"
+ "fmt"
+ "go/ast"
+ "go/build"
+ "go/parser"
+ "go/token"
+ "os"
+ "path/filepath"
+ "text/tabwriter"
+
+ "golang.org/x/tools/cover"
+)
+
+// 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 := cover.ParseProfiles(profile)
+ 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(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, 100.0*float64(c)/float64(t))
+ total += t
+ covered += c
+ }
+ }
+ fmt.Fprintf(tabber, "total:\t(statements)\t%.1f%%\n", 100.0*float64(covered)/float64(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:
+ 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 *cover.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)
+ }
+ }
+ if total == 0 {
+ total = 1 // Avoid zero denominator.
+ }
+ return covered, total
+}
+
+// findFile finds the location of the named file in GOROOT, GOPATH etc.
+func findFile(file string) (string, error) {
+ dir, file := filepath.Split(file)
+ pkg, err := build.Import(dir, ".", build.FindOnly)
+ if err != nil {
+ return "", fmt.Errorf("can't find %q: %v", file, err)
+ }
+ return filepath.Join(pkg.Dir, file), nil
+}