go.tools/cover: split parsing code out from cmd/cover

Split the profile parsing code out of cmd/cover into
a reusable package, to support third-party coverage
tools.

R=golang-dev, r, adg
CC=golang-dev
https://golang.org/cl/36050045

cmd/cover/cover.go

@@ -83,7 +83,7 @@ func main() {
 
 	// Generate coverage-annotated source.
 	if *mode != "" {
-		cover(flag.Arg(0))
+		annotate(flag.Arg(0))
 		return
 	}
 
@@ -319,7 +319,7 @@ func initialComments(content []byte) []byte {
 	return content[:end]
 }
 
-func cover(name string) {
+func annotate(name string) {
 	fset := token.NewFileSet()
 	content, err := ioutil.ReadFile(name)
 	if err != nil {

cmd/cover/func.go

@@ -10,10 +10,14 @@ import (
 	"bufio"
 	"fmt"
 	"go/ast"
+	"go/build"
 	"go/parser"
 	"go/token"
 	"os"
+	"path/filepath"
 	"text/tabwriter"
+
+	"code.google.com/p/go.tools/cover"
 )
 
 // funcOutput takes two file names as arguments, a coverage profile to read as input and an output
@@ -29,7 +33,7 @@ import (
 //	total:		(statements)		91.4%
 
 func funcOutput(profile, outputFile string) error {
-	profiles, err := ParseProfiles(profile)
+	profiles, err := cover.ParseProfiles(profile)
 	if err != nil {
 		return err
 	}
@@ -126,7 +130,7 @@ func (v *FuncVisitor) Visit(node ast.Node) ast.Visitor {
 }
 
 // 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) {
+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
@@ -150,3 +154,13 @@ func (f *FuncExtent) coverage(profile *Profile) (num, den int64) {
 	}
 	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
+}

cmd/cover/html.go

@@ -16,13 +16,15 @@ import (
 	"os/exec"
 	"path/filepath"
 	"runtime"
+
+	"code.google.com/p/go.tools/cover"
 )
 
 // 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)
+	profiles, err := cover.ParseProfiles(profile)
 	if err != nil {
 		return err
 	}
@@ -83,7 +85,7 @@ func htmlOutput(profile, outfile string) error {
 
 // 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 {
+func htmlGen(w io.Writer, src []byte, boundaries []cover.Boundary) error {
 	dst := bufio.NewWriter(w)
 	for i := range src {
 		for len(boundaries) > 0 && boundaries[0].Offset == i {

cover/profile.go

@@ -2,15 +2,15 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-package main
+// Package cover provides support for parsing coverage profiles
+// generated by "go test -coverprofile=cover.out".
+package cover
 
 import (
 	"bufio"
 	"fmt"
-	"go/build"
 	"math"
 	"os"
-	"path/filepath"
 	"regexp"
 	"sort"
 	"strconv"
@@ -37,10 +37,10 @@ func (p byFileName) Len() int           { return len(p) }
 func (p byFileName) Less(i, j int) bool { return p[i].FileName < p[j].FileName }
 func (p byFileName) Swap(i, j int)      { p[i], p[j] = p[j], p[i] }
 
-// ParseProfiles parses profile data from the given Reader and returns a
+// ParseProfiles parses profile data in the specified file and returns a
-// Profile for each file.
+// Profile for each source file described therein.
 func ParseProfiles(fileName string) ([]*Profile, error) {
-	pf, err := os.Open(profile)
+	pf, err := os.Open(fileName)
 	if err != nil {
 		return nil, err
 	}
@@ -188,13 +188,3 @@ func (b boundariesByPos) Less(i, j int) bool {
 	}
 	return b[i].Offset < b[j].Offset
 }
-
-// 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
-}