blob: 56a2401c7b248b12cd61cf388d98490f87a6e94e [file] [log] [blame]
// Copyright 2010 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 the code dealing with package directory trees.
package pkgdoc
import (
"bytes"
"go/ast"
"go/doc"
"go/parser"
"go/token"
"log"
"path"
"strings"
"golang.org/x/website/internal/backport/io/fs"
)
type Dir struct {
Path string // directory path
HasPkg bool // true if the directory contains at least one package
Synopsis string // package documentation, if any
Dirs []*Dir // subdirectories
}
func (d *Dir) Name() string {
return path.Base(d.Path)
}
// DirEntry describes a directory entry.
// The Depth gives the directory depth relative to the overall list,
// for use in presenting a hierarchical directory entry.
type DirEntry struct {
Depth int // >= 0
Path string // relative path to directory from listing start
HasPkg bool // true if the directory contains at least one package
Synopsis string // package documentation, if any
}
func (d *DirEntry) Name() string {
return path.Base(d.Path)
}
// lookup looks for the *Dir for a given named path, relative to d.
func (d *Dir) lookup(name string) *Dir {
name = path.Join(d.Path, name)
if name == d.Path {
return d
}
if d.Path != "." {
if !strings.HasPrefix(name, d.Path) || name[len(d.Path)] != '/' {
return nil
}
name = name[len(d.Path)+1:]
}
Walk:
for i := 0; i <= len(name); i++ {
if i == len(name) || name[i] == '/' {
// Find next child along path.
for _, sub := range d.Dirs {
if sub.Path == name[:i] {
d = sub
continue Walk
}
}
return nil
}
}
return d
}
// list creates a (linear) directory list from a directory tree.
// If filter is set, only the directory entries whose paths match the filter
// are included.
func (d *Dir) list(filter func(string) bool) []DirEntry {
if d == nil {
return nil
}
root := d
var list []DirEntry
root.walk(func(d *Dir, depth int) {
if depth == 0 || filter != nil && !filter(d.Path) {
return
}
// the path is relative to root.Path - remove the root.Path
// prefix (the prefix should always be present but avoid
// crashes and check)
path := strings.TrimPrefix(d.Path, root.Path)
// remove leading separator if any - path must be relative
path = strings.TrimPrefix(path, "/")
list = append(list, DirEntry{
Depth: depth,
Path: path,
HasPkg: d.HasPkg,
Synopsis: d.Synopsis,
})
})
if len(list) == 0 {
return nil
}
return list
}
// newDir returns a Dir describing dirpath in fsys.
// When Go files need to be parsed, newDir uses fset.
// If there are no package files and no subdirectories containing packages,
// newDir returns nil.
func newDir(fsys fs.FS, fset *token.FileSet, dirpath string) *Dir {
var synopses [3]string // prioritized package documentation (0 == highest priority)
hasPkgFiles := false
haveSummary := false
list, err := fs.ReadDir(fsys, dirpath)
if err != nil {
// TODO: propagate more. See golang.org/issue/14252.
log.Printf("newDirTree reading %s: %v", dirpath, err)
}
// determine number of subdirectories and if there are package files
var dirs []*Dir
for _, de := range list {
filename := path.Join(dirpath, de.Name())
switch {
case isPkgDir(de):
d := newDir(fsys, fset, filename)
if d != nil {
dirs = append(dirs, d)
}
case !haveSummary && isPkgFile(de):
// looks like a package file, but may just be a file ending in ".go";
// don't just count it yet (otherwise we may end up with hasPkgFiles even
// though the directory doesn't contain any real package files - was bug)
// no "optimal" package synopsis yet; continue to collect synopses
const flags = parser.ParseComments | parser.PackageClauseOnly
file, err := parseFile(fsys, fset, filename, flags)
if err != nil {
log.Printf("parsing %v: %v", filename, err)
break
}
hasPkgFiles = true
if file.Doc != nil {
// prioritize documentation
i := -1
switch file.Name.Name {
case path.Base(dirpath):
i = 0 // normal case: directory name matches package name
case "main":
i = 1 // directory contains a main package
default:
i = 2 // none of the above
}
if 0 <= i && i < len(synopses) && synopses[i] == "" {
synopses[i] = doc.Synopsis(file.Doc.Text())
}
}
haveSummary = synopses[0] != ""
}
}
// if there are no package files and no subdirectories
// containing package files, ignore the directory
if !hasPkgFiles && len(dirs) == 0 {
return nil
}
// select the highest-priority synopsis for the directory entry, if any
synopsis := ""
for _, synopsis = range synopses {
if synopsis != "" {
break
}
}
return &Dir{
Path: dirpath,
HasPkg: hasPkgFiles,
Synopsis: synopsis,
Dirs: dirs,
}
}
func isPkgFile(fi fs.DirEntry) bool {
name := fi.Name()
return !fi.IsDir() &&
path.Ext(name) == ".go" &&
!strings.HasSuffix(fi.Name(), "_test.go") // ignore test files
}
func isPkgDir(fi fs.DirEntry) bool {
name := fi.Name()
return fi.IsDir() &&
name != "testdata" &&
len(name) > 0 && name[0] != '_' && name[0] != '.' // ignore _files and .files
}
// walk calls f for each directory in the tree rooted at d, including d itself.
// The depth argument specifies the depth of the directory in the tree.
// The depth of d itself is 0.
func (d *Dir) walk(f func(d *Dir, depth int)) {
walkDirs(f, d, 0)
}
func walkDirs(f func(d *Dir, depth int), d *Dir, depth int) {
f(d, depth)
for _, sub := range d.Dirs {
walkDirs(f, sub, depth+1)
}
}
func parseFile(fsys fs.FS, fset *token.FileSet, filename string, mode parser.Mode) (*ast.File, error) {
src, err := fs.ReadFile(fsys, filename)
if err != nil {
return nil, err
}
// Temporary ad-hoc fix for issue 5247.
// TODO(gri,dmitshur) Remove this in favor of a better fix, eventually (see issue 32092).
replaceLinePrefixCommentsWithBlankLine(src)
return parser.ParseFile(fset, filename, src, mode)
}
func parseFiles(fsys fs.FS, fset *token.FileSet, dirname string, localnames []string) (map[string]*ast.File, error) {
files := make(map[string]*ast.File)
for _, f := range localnames {
filename := path.Join(dirname, f)
file, err := parseFile(fsys, fset, filename, parser.ParseComments)
if err != nil {
return nil, err
}
files[filename] = file
}
return files, nil
}
var linePrefix = []byte("//line ")
// This function replaces source lines starting with "//line " with a blank line.
// It does this irrespective of whether the line is truly a line comment or not;
// e.g., the line may be inside a string, or a /*-style comment; however that is
// rather unlikely (proper testing would require a full Go scan which we want to
// avoid for performance).
func replaceLinePrefixCommentsWithBlankLine(src []byte) {
for {
i := bytes.Index(src, linePrefix)
if i < 0 {
break // we're done
}
// 0 <= i && i+len(linePrefix) <= len(src)
if i == 0 || src[i-1] == '\n' {
// at beginning of line: blank out line
for i < len(src) && src[i] != '\n' {
src[i] = ' '
i++
}
} else {
// not at beginning of line: skip over prefix
i += len(linePrefix)
}
// i <= len(src)
src = src[i:]
}
}