godoc: search GOPATH for documentation

R=rsc, mattn.jp
CC=golang-dev
https://golang.org/cl/4627065

src/cmd/godoc/godoc.go

@@ -9,6 +9,7 @@ import (
 	"flag"
 	"fmt"
 	"go/ast"
+	"go/build"
 	"go/doc"
 	"go/printer"
 	"go/token"
@@ -83,7 +84,15 @@ var (
 
 
 func initHandlers() {
-	fsMap.Init(*pkgPath)
+	paths := filepath.SplitList(*pkgPath)
+	for _, t := range build.Path {
+		if t.Goroot {
+			continue
+		}
+		paths = append(paths, t.SrcDir())
+	}
+	fsMap.Init(paths)
+
 	fileServer = http.FileServer(http.Dir(*goroot))
 	cmdHandler = httpHandler{"/cmd/", filepath.Join(*goroot, "src", "cmd"), false}
 	pkgHandler = httpHandler{"/pkg/", filepath.Join(*goroot, "src", "pkg"), true}

src/cmd/godoc/main.go

@@ -31,6 +31,7 @@ import (
 	"flag"
 	"fmt"
 	"go/ast"
+	"go/build"
 	"http"
 	_ "http/pprof" // to serve /debug/pprof/*
 	"io"
@@ -332,7 +333,10 @@ func main() {
 	}
 	relpath := path
 	abspath := path
-	if !filepath.IsAbs(path) {
+	if t, pkg, err := build.FindTree(path); err == nil {
+		relpath = pkg
+		abspath = filepath.Join(t.SrcDir(), pkg)
+	} else if !filepath.IsAbs(path) {
 		abspath = absolutePath(path, pkgHandler.fsRoot)
 	} else {
 		relpath = relativeURL(path)

src/cmd/godoc/mapping.go

@@ -59,10 +59,10 @@ type mapping struct {
 }
 
 
-// Init initializes the Mapping from a list of paths separated by
-// filepath.ListSeparator. Empty paths are ignored; relative paths
-// are assumed to be relative to the current working directory and
-// converted to absolute paths. For each path of the form:
+// Init initializes the Mapping from a list of paths.
+// Empty paths are ignored; relative paths are assumed to be relative to
+// the current working directory and converted to absolute paths.
+// For each path of the form:
 //
 //	dirname/localname
 //
@@ -80,8 +80,8 @@ type mapping struct {
 //	user   -> /home/user
 //	public -> /home/build/public
 //
-func (m *Mapping) Init(paths string) {
-	pathlist := canonicalizePaths(filepath.SplitList(paths), nil)
+func (m *Mapping) Init(paths []string) {
+	pathlist := canonicalizePaths(paths, nil)
 	list := make([]mapping, len(pathlist))
 
 	// create mapping list