godoc: replace direct OS file system accesses in favor

of accesses via a FileSystem interface.

Preparation for appengine version which gets its files
via a snapshot or zip file and uses a corresponding
FileSystem implementation.

R=rsc, r
CC=golang-dev
https://golang.org/cl/4572065

src/cmd/godoc/Makefile

@@ -8,11 +8,13 @@ TARG=godoc
 GOFILES=\
 	codewalk.go\
 	dirtrees.go\
+	filesystem.go\
 	format.go\
 	godoc.go\
 	index.go\
 	main.go\
 	mapping.go\
+	parser.go\
 	snippet.go\
 	spec.go\
 	utils.go\

src/cmd/godoc/codewalk.go

@@ -17,7 +17,6 @@ import (
 	"fmt"
 	"http"
 	"io"
-	"io/ioutil"
 	"log"
 	"os"
 	"regexp"
@@ -42,7 +41,7 @@ func codewalk(w http.ResponseWriter, r *http.Request) {
 	}
 
 	// If directory exists, serve list of code walks.
-	dir, err := os.Lstat(abspath)
+	dir, err := fs.Lstat(abspath)
 	if err == nil && dir.IsDirectory() {
 		codewalkDir(w, r, relpath, abspath)
 		return
@@ -114,8 +113,8 @@ func (st *Codestep) String() string {
 
 
 // loadCodewalk reads a codewalk from the named XML file.
-func loadCodewalk(file string) (*Codewalk, os.Error) {
+func loadCodewalk(filename string) (*Codewalk, os.Error) {
-	f, err := os.Open(file)
+	f, err := fs.Open(filename)
 	if err != nil {
 		return nil, err
 	}
@@ -125,7 +124,7 @@ func loadCodewalk(file string) (*Codewalk, os.Error) {
 	p.Entity = xml.HTMLEntity
 	err = p.Unmarshal(cw, nil)
 	if err != nil {
-		return nil, &os.PathError{"parsing", file, err}
+		return nil, &os.PathError{"parsing", filename, err}
 	}
 
 	// Compute file list, evaluate line numbers for addresses.
@@ -135,8 +134,8 @@ func loadCodewalk(file string) (*Codewalk, os.Error) {
 		if i < 0 {
 			i = len(st.Src)
 		}
-		file := st.Src[0:i]
+		filename := st.Src[0:i]
-		data, err := ioutil.ReadFile(absolutePath(file, *goroot))
+		data, err := fs.ReadFile(absolutePath(filename, *goroot))
 		if err != nil {
 			st.Err = err
 			continue
@@ -158,8 +157,8 @@ func loadCodewalk(file string) (*Codewalk, os.Error) {
 			st.Hi = byteToLine(data, hi-1)
 		}
 		st.Data = data
-		st.File = file
+		st.File = filename
-		m[file] = true
+		m[filename] = true
 	}
 
 	// Make list of files
@@ -184,7 +183,7 @@ func codewalkDir(w http.ResponseWriter, r *http.Request, relpath, abspath string
 		Title string
 	}
 
-	dir, err := ioutil.ReadDir(abspath)
+	dir, err := fs.ReadDir(abspath)
 	if err != nil {
 		log.Print(err)
 		serveError(w, r, relpath, err)
@@ -192,14 +191,15 @@ func codewalkDir(w http.ResponseWriter, r *http.Request, relpath, abspath string
 	}
 	var v vector.Vector
 	for _, fi := range dir {
+		name := fi.Name()
 		if fi.IsDirectory() {
-			v.Push(&elem{fi.Name + "/", ""})
+			v.Push(&elem{name + "/", ""})
-		} else if strings.HasSuffix(fi.Name, ".xml") {
+		} else if strings.HasSuffix(name, ".xml") {
-			cw, err := loadCodewalk(abspath + "/" + fi.Name)
+			cw, err := loadCodewalk(abspath + "/" + name)
 			if err != nil {
 				continue
 			}
-			v.Push(&elem{fi.Name[0 : len(fi.Name)-len(".xml")], cw.Title})
+			v.Push(&elem{name[0 : len(name)-len(".xml")], cw.Title})
 		}
 	}
 
@@ -216,7 +216,7 @@ func codewalkDir(w http.ResponseWriter, r *http.Request, relpath, abspath string
 // the usual godoc HTML wrapper.
 func codewalkFileprint(w http.ResponseWriter, r *http.Request, f string) {
 	abspath := absolutePath(f, *goroot)
-	data, err := ioutil.ReadFile(abspath)
+	data, err := fs.ReadFile(abspath)
 	if err != nil {
 		log.Print(err)
 		serveError(w, r, f, err)

src/cmd/godoc/dirtrees.go

@@ -11,9 +11,7 @@ import (
 	"go/doc"
 	"go/parser"
 	"go/token"
-	"io/ioutil"
 	"log"
-	"os"
 	"path/filepath"
 	"strings"
 	"unicode"
@@ -29,21 +27,23 @@ type Directory struct {
 }
 
 
-func isGoFile(f *os.FileInfo) bool {
+func isGoFile(fi FileInfo) bool {
-	return f.IsRegular() &&
+	name := fi.Name()
-		!strings.HasPrefix(f.Name, ".") && // ignore .files
+	return fi.IsRegular() &&
-		filepath.Ext(f.Name) == ".go"
+		!strings.HasPrefix(name, ".") && // ignore .files
+		filepath.Ext(name) == ".go"
 }
 
 
-func isPkgFile(f *os.FileInfo) bool {
+func isPkgFile(fi FileInfo) bool {
-	return isGoFile(f) &&
+	return isGoFile(fi) &&
-		!strings.HasSuffix(f.Name, "_test.go") // ignore test files
+		!strings.HasSuffix(fi.Name(), "_test.go") // ignore test files
 }
 
 
-func isPkgDir(f *os.FileInfo) bool {
+func isPkgDir(fi FileInfo) bool {
-	return f.IsDirectory() && len(f.Name) > 0 && f.Name[0] != '_'
+	name := fi.Name()
+	return fi.IsDirectory() && len(name) > 0 && name[0] != '_'
 }
 
 
@@ -101,12 +101,12 @@ func (b *treeBuilder) newDirTree(fset *token.FileSet, path, name string, depth i
 		return &Directory{depth, path, name, "", nil}
 	}
 
-	list, err := ioutil.ReadDir(path)
+	list, err := fs.ReadDir(path)
 	if err != nil {
 		// newDirTree is called with a path that should be a package
 		// directory; errors here should not happen, but if they do,
 		// we want to know about them
-		log.Printf("ioutil.ReadDir(%s): %s", path, err)
+		log.Printf("ReadDir(%s): %s", path, err)
 	}
 
 	// determine number of subdirectories and if there are package files
@@ -123,7 +123,7 @@ func (b *treeBuilder) newDirTree(fset *token.FileSet, path, name string, depth i
 			// though the directory doesn't contain any real package files - was bug)
 			if synopses[0] == "" {
 				// no "optimal" package synopsis yet; continue to collect synopses
-				file, err := parser.ParseFile(fset, filepath.Join(path, d.Name), nil,
+				file, err := parser.ParseFile(fset, filepath.Join(path, d.Name()), nil,
 					parser.ParseComments|parser.PackageClauseOnly)
 				if err == nil {
 					hasPkgFiles = true
@@ -156,7 +156,8 @@ func (b *treeBuilder) newDirTree(fset *token.FileSet, path, name string, depth i
 		i := 0
 		for _, d := range list {
 			if isPkgDir(d) {
-				dd := b.newDirTree(fset, filepath.Join(path, d.Name), d.Name, depth+1)
+				name := d.Name()
+				dd := b.newDirTree(fset, filepath.Join(path, name), name, depth+1)
 				if dd != nil {
 					dirs[i] = dd
 					i++
@@ -195,8 +196,8 @@ func (b *treeBuilder) newDirTree(fset *token.FileSet, path, name string, depth i
 // (i.e., in this case the tree may contain directories w/o any package files).
 //
 func newDirectory(root string, pathFilter func(string) bool, maxDepth int) *Directory {
-	// The root could be a symbolic link so use os.Stat not os.Lstat.
+	// The root could be a symbolic link so use Stat not Lstat.
-	d, err := os.Stat(root)
+	d, err := fs.Stat(root)
 	// If we fail here, report detailed error messages; otherwise
 	// is is hard to see why a directory tree was not built.
 	switch {
@@ -213,7 +214,7 @@ func newDirectory(root string, pathFilter func(string) bool, maxDepth int) *Dire
 	b := treeBuilder{pathFilter, maxDepth}
 	// the file set provided is only for local parsing, no position
 	// information escapes and thus we don't need to save the set
-	return b.newDirTree(token.NewFileSet(), root, d.Name, 0)
+	return b.newDirTree(token.NewFileSet(), root, d.Name(), 0)
 }
 
 

src/cmd/godoc/filesystem.go

@@ -0,0 +1,96 @@
+// Copyright 2011 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 defines abstract file system access.
+
+package main
+
+import (
+	"io"
+	"io/ioutil"
+	"os"
+)
+
+
+// The FileInfo interface provides access to file information.
+type FileInfo interface {
+	Name() string
+	Size() int64
+	IsRegular() bool
+	IsDirectory() bool
+}
+
+
+// The FileSystem interface specifies the methods godoc is using
+// to access the file system for which it serves documentation.
+type FileSystem interface {
+	Open(path string) (io.ReadCloser, os.Error)
+	Lstat(path string) (FileInfo, os.Error)
+	Stat(path string) (FileInfo, os.Error)
+	ReadDir(path string) ([]FileInfo, os.Error)
+	ReadFile(path string) ([]byte, os.Error)
+}
+
+
+// ----------------------------------------------------------------------------
+// OS-specific FileSystem implementation
+
+var OS FileSystem = osFS{}
+
+
+// osFI is the OS-specific implementation of FileInfo.
+type osFI struct {
+	*os.FileInfo
+}
+
+
+func (fi osFI) Name() string {
+	return fi.FileInfo.Name
+}
+
+
+func (fi osFI) Size() int64 {
+	if fi.IsDirectory() {
+		return 0
+	}
+	return fi.FileInfo.Size
+}
+
+
+// osFS is the OS-specific implementation of FileSystem
+type osFS struct{}
+
+func (osFS) Open(path string) (io.ReadCloser, os.Error) {
+	return os.Open(path)
+}
+
+
+func (osFS) Lstat(path string) (FileInfo, os.Error) {
+	fi, err := os.Lstat(path)
+	return osFI{fi}, err
+}
+
+
+func (osFS) Stat(path string) (FileInfo, os.Error) {
+	fi, err := os.Stat(path)
+	return osFI{fi}, err
+}
+
+
+func (osFS) ReadDir(path string) ([]FileInfo, os.Error) {
+	l0, err := ioutil.ReadDir(path)
+	if err != nil {
+		return nil, err
+	}
+	l1 := make([]FileInfo, len(l0))
+	for i, e := range l0 {
+		l1[i] = osFI{e}
+	}
+	return l1, nil
+}
+
+
+func (osFS) ReadFile(path string) ([]byte, os.Error) {
+	return ioutil.ReadFile(path)
+}

src/cmd/godoc/godoc.go

@@ -10,12 +10,10 @@ import (
 	"fmt"
 	"go/ast"
 	"go/doc"
-	"go/parser"
 	"go/printer"
 	"go/token"
 	"http"
 	"io"
-	"io/ioutil"
 	"log"
 	"os"
 	"path"
@@ -71,6 +69,7 @@ var (
 	maxResults   = flag.Int("maxresults", 10000, "maximum number of full text search results shown")
 
 	// file system mapping
+	fs         FileSystem // the underlying file system
 	fsMap      Mapping    // user-defined mapping
 	fsTree     RWValue    // *Directory tree of packages, updated with each sync
 	pathFilter RWValue    // filter used when building fsMap directory trees
@@ -147,13 +146,13 @@ func getPathFilter() func(string) bool {
 // readDirList reads a file containing a newline-separated list
 // of directory paths and returns the list of paths.
 func readDirList(filename string) ([]string, os.Error) {
-	contents, err := ioutil.ReadFile(filename)
+	contents, err := fs.ReadFile(filename)
 	if err != nil {
 		return nil, err
 	}
 	// create a sorted list of valid directory names
 	filter := func(path string) bool {
-		d, e := os.Lstat(path)
+		d, e := fs.Lstat(path)
 		if e != nil && err == nil {
 			// remember first error and return it from readDirList
 			// so we have at least some information if things go bad
@@ -598,7 +597,7 @@ func timeFmt(w io.Writer, format string, x ...interface{}) {
 
 // Template formatter for "dir/" format.
 func dirslashFmt(w io.Writer, format string, x ...interface{}) {
-	if x[0].(*os.FileInfo).IsDirectory() {
+	if x[0].(FileInfo).IsDirectory() {
 		w.Write([]byte{'/'})
 	}
 }
@@ -642,12 +641,12 @@ func readTemplate(name string) *template.Template {
 	if *templateDir != "" {
 		defaultpath := path
 		path = filepath.Join(*templateDir, name)
-		if _, err := os.Stat(path); err != nil {
+		if _, err := fs.Stat(path); err != nil {
 			log.Print("readTemplate:", err)
 			path = defaultpath
 		}
 	}
-	data, err := ioutil.ReadFile(path)
+	data, err := fs.ReadFile(path)
 	if err != nil {
 		log.Fatalf("ReadFile %s: %v", path, err)
 	}
@@ -742,9 +741,9 @@ func extractString(src []byte, rx *regexp.Regexp) (s string) {
 
 func serveHTMLDoc(w http.ResponseWriter, r *http.Request, abspath, relpath string) {
 	// get HTML body contents
-	src, err := ioutil.ReadFile(abspath)
+	src, err := fs.ReadFile(abspath)
 	if err != nil {
-		log.Printf("ioutil.ReadFile: %s", err)
+		log.Printf("ReadFile: %s", err)
 		serveError(w, r, relpath, err)
 		return
 	}
@@ -793,9 +792,9 @@ func redirect(w http.ResponseWriter, r *http.Request) (redirected bool) {
 }
 
 func serveTextFile(w http.ResponseWriter, r *http.Request, abspath, relpath, title string) {
-	src, err := ioutil.ReadFile(abspath)
+	src, err := fs.ReadFile(abspath)
 	if err != nil {
-		log.Printf("ioutil.ReadFile: %s", err)
+		log.Printf("ReadFile: %s", err)
 		serveError(w, r, relpath, err)
 		return
 	}
@@ -814,19 +813,13 @@ func serveDirectory(w http.ResponseWriter, r *http.Request, abspath, relpath str
 		return
 	}
 
-	list, err := ioutil.ReadDir(abspath)
+	list, err := fs.ReadDir(abspath)
 	if err != nil {
-		log.Printf("ioutil.ReadDir: %s", err)
+		log.Printf("ReadDir: %s", err)
 		serveError(w, r, relpath, err)
 		return
 	}
 
-	for _, d := range list {
-		if d.IsDirectory() {
-			d.Size = 0
-		}
-	}
-
 	contents := applyTemplate(dirlistHTML, "dirlistHTML", list)
 	servePage(w, "Directory "+relpath, "", "", contents)
 }
@@ -864,7 +857,7 @@ func serveFile(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	dir, err := os.Lstat(abspath)
+	dir, err := fs.Lstat(abspath)
 	if err != nil {
 		log.Print(err)
 		serveError(w, r, relpath, err)
@@ -942,15 +935,15 @@ type httpHandler struct {
 //
 func (h *httpHandler) getPageInfo(abspath, relpath, pkgname string, mode PageInfoMode) PageInfo {
 	// filter function to select the desired .go files
-	filter := func(d *os.FileInfo) bool {
+	filter := func(d FileInfo) bool {
 		// If we are looking at cmd documentation, only accept
 		// the special fakePkgFile containing the documentation.
-		return isPkgFile(d) && (h.isPkg || d.Name == fakePkgFile)
+		return isPkgFile(d) && (h.isPkg || d.Name() == fakePkgFile)
 	}
 
 	// get package ASTs
 	fset := token.NewFileSet()
-	pkgs, err := parser.ParseDir(fset, abspath, filter, parser.ParseComments)
+	pkgs, err := parseDir(fset, abspath, filter)
 	if err != nil && pkgs == nil {
 		// only report directory read errors, ignore parse errors
 		// (may be able to extract partial package information)

src/cmd/godoc/index.go

@@ -45,7 +45,6 @@ import (
 	"go/token"
 	"go/scanner"
 	"index/suffixarray"
-	"io/ioutil"
 	"os"
 	"path/filepath"
 	"regexp"
@@ -624,7 +623,7 @@ func pkgName(filename string) string {
 // failed (that is, if the file was not added), it returns file == nil.
 func (x *Indexer) addFile(filename string, goFile bool) (file *token.File, ast *ast.File) {
 	// open file
-	f, err := os.Open(filename)
+	f, err := fs.Open(filename)
 	if err != nil {
 		return
 	}
@@ -727,12 +726,12 @@ func isWhitelisted(filename string) bool {
 }
 
 
-func (x *Indexer) visitFile(dirname string, f *os.FileInfo, fulltextIndex bool) {
+func (x *Indexer) visitFile(dirname string, f FileInfo, fulltextIndex bool) {
 	if !f.IsRegular() {
 		return
 	}
 
-	filename := filepath.Join(dirname, f.Name)
+	filename := filepath.Join(dirname, f.Name())
 	goFile := false
 
 	switch {
@@ -745,7 +744,7 @@ func (x *Indexer) visitFile(dirname string, f *os.FileInfo, fulltextIndex bool)
 		}
 		goFile = true
 
-	case !fulltextIndex || !isWhitelisted(f.Name):
+	case !fulltextIndex || !isWhitelisted(f.Name()):
 		return
 	}
 
@@ -804,7 +803,7 @@ func NewIndex(dirnames <-chan string, fulltextIndex bool) *Index {
 
 	// index all files in the directories given by dirnames
 	for dirname := range dirnames {
-		list, err := ioutil.ReadDir(dirname)
+		list, err := fs.ReadDir(dirname)
 		if err != nil {
 			continue // ignore this directory
 		}

src/cmd/godoc/main.go

@@ -222,6 +222,10 @@ func main() {
 	flag.Usage = usage
 	flag.Parse()
 
+	// Determine file system to use.
+	// TODO(gri) Complete this - for now we only have one.
+	fs = OS
+
 	// Clean goroot: normalize path separator.
 	*goroot = filepath.Clean(*goroot)
 

src/cmd/godoc/mapping.go

@@ -9,7 +9,6 @@ package main
 import (
 	"fmt"
 	"io"
-	"os"
 	"path"
 	"path/filepath"
 	"sort"
@@ -174,7 +173,7 @@ func (m *Mapping) ToAbsolute(spath string) string {
 			continue // no match
 		}
 		abspath := filepath.Join(e.path, tail)
-		if _, err := os.Stat(abspath); err == nil {
+		if _, err := fs.Stat(abspath); err == nil {
 			return abspath
 		}
 	}

src/cmd/godoc/parser.go

@@ -0,0 +1,69 @@
+// Copyright 2011 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 contains support functions for parsing .go files.
+// Similar functionality is found in package go/parser but the
+// functions here operate using godoc's file system fs instead
+// of calling the OS's file operations directly.
+
+package main
+
+import (
+	"go/ast"
+	"go/parser"
+	"go/token"
+	"os"
+	"path/filepath"
+)
+
+func parseFiles(fset *token.FileSet, filenames []string) (pkgs map[string]*ast.Package, first os.Error) {
+	pkgs = make(map[string]*ast.Package)
+	for _, filename := range filenames {
+		src, err := fs.ReadFile(filename)
+		if err != nil {
+			if first == nil {
+				first = err
+			}
+			continue
+		}
+
+		file, err := parser.ParseFile(fset, filename, src, parser.ParseComments)
+		if err != nil {
+			if first == nil {
+				first = err
+			}
+			continue
+		}
+
+		name := file.Name.Name
+		pkg, found := pkgs[name]
+		if !found {
+			// TODO(gri) Use NewPackage here; reconsider ParseFiles API.
+			pkg = &ast.Package{name, nil, nil, make(map[string]*ast.File)}
+			pkgs[name] = pkg
+		}
+		pkg.Files[filename] = file
+	}
+	return
+}
+
+
+func parseDir(fset *token.FileSet, path string, filter func(FileInfo) bool) (map[string]*ast.Package, os.Error) {
+	list, err := fs.ReadDir(path)
+	if err != nil {
+		return nil, err
+	}
+
+	filenames := make([]string, len(list))
+	i := 0
+	for _, d := range list {
+		if filter == nil || filter(d) {
+			filenames[i] = filepath.Join(path, d.Name())
+			i++
+		}
+	}
+	filenames = filenames[0:i]
+
+	return parseFiles(fset, filenames)
+}

src/cmd/godoc/utils.go

@@ -44,6 +44,10 @@ func (v *RWValue) get() (interface{}, int64) {
 }
 
 
+// TODO(gri) For now, using os.Getwd() is ok here since the functionality
+//           based on this code is not invoked for the appengine version,
+//           but this is fragile. Determine what the right thing to do is,
+//           here (possibly have some Getwd-equivalent in FileSystem).
 var cwd, _ = os.Getwd() // ignore errors
 
 // canonicalizePaths takes a list of (directory/file) paths and returns
@@ -95,6 +99,7 @@ func canonicalizePaths(list []string, filter func(path string) bool) []string {
 // atomically renames that file to the file named by filename.
 //
 func writeFileAtomically(filename string, data []byte) os.Error {
+	// TODO(gri) this won't work on appengine
 	f, err := ioutil.TempFile(filepath.Split(filename))
 	if err != nil {
 		return err
@@ -155,7 +160,7 @@ func isTextFile(filename string) bool {
 
 	// the extension is not known; read an initial chunk
 	// of the file and check if it looks like text
-	f, err := os.Open(filename)
+	f, err := fs.Open(filename)
 	if err != nil {
 		return false
 	}