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Copy pathdirtrees.go
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383 lines (343 loc) · 10 KB
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// 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 godoc
import (
"go/doc"
"go/parser"
"go/token"
"log"
"os"
pathpkg "path"
"runtime"
"sort"
"strings"
"golang.org/x/tools/godoc/vfs"
)
// Conventional name for directories containing test data.
// Excluded from directory trees.
//
const testdataDirName = "testdata"
type Directory struct {
Depth int
Path string // directory path; includes Name
Name string // directory name
HasPkg bool // true if the directory contains at least one package
Synopsis string // package documentation, if any
RootType vfs.RootType // root type of the filesystem containing the directory
Dirs []*Directory // subdirectories
}
func isGoFile(fi os.FileInfo) bool {
name := fi.Name()
return !fi.IsDir() &&
len(name) > 0 && name[0] != '.' && // ignore .files
pathpkg.Ext(name) == ".go"
}
func isPkgFile(fi os.FileInfo) bool {
return isGoFile(fi) &&
!strings.HasSuffix(fi.Name(), "_test.go") // ignore test files
}
func isPkgDir(fi os.FileInfo) bool {
name := fi.Name()
return fi.IsDir() && len(name) > 0 &&
name[0] != '_' && name[0] != '.' // ignore _files and .files
}
type treeBuilder struct {
c *Corpus
maxDepth int
}
// ioGate is a semaphore controlling VFS activity (ReadDir, parseFile, etc).
// Send before an operation and receive after.
var ioGate = make(chan struct{}, 20)
// workGate controls the number of concurrent workers. Too many concurrent
// workers and performance degrades and the race detector gets overwhelmed. If
// we cannot check out a concurrent worker, work is performed by the main thread
// instead of spinning up another goroutine.
var workGate = make(chan struct{}, runtime.NumCPU()*4)
func (b *treeBuilder) newDirTree(fset *token.FileSet, path, name string, depth int) *Directory {
if name == testdataDirName {
return nil
}
if depth >= b.maxDepth {
// return a dummy directory so that the parent directory
// doesn't get discarded just because we reached the max
// directory depth
return &Directory{
Depth: depth,
Path: path,
Name: name,
}
}
var synopses [3]string // prioritized package documentation (0 == highest priority)
show := true // show in package listing
hasPkgFiles := false
haveSummary := false
if hook := b.c.SummarizePackage; hook != nil {
if summary, show0, ok := hook(strings.TrimPrefix(path, "/src/")); ok {
hasPkgFiles = true
show = show0
synopses[0] = summary
haveSummary = true
}
}
ioGate <- struct{}{}
list, err := b.c.fs.ReadDir(path)
<-ioGate
if err != nil {
// TODO: propagate more. See golang.org/issue/14252.
// For now:
if b.c.Verbose {
log.Printf("newDirTree reading %s: %v", path, err)
}
}
// determine number of subdirectories and if there are package files
var dirchs []chan *Directory
var dirs []*Directory
for _, d := range list {
filename := pathpkg.Join(path, d.Name())
switch {
case isPkgDir(d):
name := d.Name()
select {
case workGate <- struct{}{}:
ch := make(chan *Directory, 1)
dirchs = append(dirchs, ch)
go func() {
ch <- b.newDirTree(fset, filename, name, depth+1)
<-workGate
}()
default:
// no free workers, do work synchronously
dir := b.newDirTree(fset, filename, name, depth+1)
if dir != nil {
dirs = append(dirs, dir)
}
}
case !haveSummary && isPkgFile(d):
// 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
ioGate <- struct{}{}
const flags = parser.ParseComments | parser.PackageClauseOnly
file, err := b.c.parseFile(fset, filename, flags)
<-ioGate
if err != nil {
if b.c.Verbose {
log.Printf("Error parsing %v: %v", filename, err)
}
break
}
hasPkgFiles = true
if file.Doc != nil {
// prioritize documentation
i := -1
switch file.Name.Name {
case name:
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] != ""
}
}
// create subdirectory tree
for _, ch := range dirchs {
if d := <-ch; d != nil {
dirs = append(dirs, d)
}
}
// We need to sort the dirs slice because
// it is appended again after reading from dirchs.
sort.Slice(dirs, func(i, j int) bool {
return dirs[i].Name < dirs[j].Name
})
// 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 &Directory{
Depth: depth,
Path: path,
Name: name,
HasPkg: hasPkgFiles && show, // TODO(bradfitz): add proper Hide field?
Synopsis: synopsis,
RootType: b.c.fs.RootType(path),
Dirs: dirs,
<
8000
div>
}
}
// newDirectory creates a new package directory tree with at most maxDepth
// levels, anchored at root. The result tree is pruned such that it only
// contains directories that contain package files or that contain
// subdirectories containing package files (transitively). If a non-nil
// pathFilter is provided, directory paths additionally must be accepted
// by the filter (i.e., pathFilter(path) must be true). If a value >= 0 is
// provided for maxDepth, nodes at larger depths are pruned as well; they
// are assumed to contain package files even if their contents are not known
// (i.e., in this case the tree may contain directories w/o any package files).
//
func (c *Corpus) newDirectory(root string, maxDepth int) *Directory {
// The root could be a symbolic link so use Stat not Lstat.
d, err := c.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 {
case err != nil:
log.Printf("newDirectory(%s): %s", root, err)
return nil
case root != "/" && !isPkgDir(d):
log.Printf("newDirectory(%s): not a package directory", root)
return nil
case root == "/" && !d.IsDir():
log.Printf("newDirectory(%s): not a directory", root)
return nil
}
if maxDepth < 0 {
maxDepth = 1e6 // "infinity"
}
b := treeBuilder{c, 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)
}
func (dir *Directory) walk(c chan<- *Directory, skipRoot bool) {
if dir != nil {
if !skipRoot {
c <- dir
}
for _, d := range dir.Dirs {
d.walk(c, false)
}
}
}
func (dir *Directory) iter(skipRoot bool) <-chan *Directory {
c := make(chan *Directory)
go func() {
dir.walk(c, skipRoot)
close(c)
}()
return c
}
func (dir *Directory) lookupLocal(name string) *Directory {
for _, d := range dir.Dirs {
if d.Name == name {
return d
}
}
return nil
}
func splitPath(p string) []string {
p = strings.TrimPrefix(p, "/")
if p == "" {
return nil
}
return strings.Split(p, "/")
}
// lookup looks for the *Directory for a given path, relative to dir.
func (dir *Directory) lookup(path string) *Directory {
d := splitPath(dir.Path)
p := splitPath(path)
i := 0
for i < len(d) {
if i >= len(p) || d[i] != p[i] {
return nil
}
i++
}
for dir != nil && i < len(p) {
dir = dir.lookupLocal(p[i])
i++
}
return dir
}
// DirEntry describes a directory entry. The Depth and Height values
// are useful for presenting an entry in an indented fashion.
//
type DirEntry struct {
Depth int // >= 0
Height int // = DirList.MaxHeight - Depth, > 0
Path string // directory path; includes Name, relative to DirList root
Name string // directory name
HasPkg bool // true if the directory contains at least one package
Synopsis string // package documentation, if any
RootType vfs.RootType // root type of the filesystem containing the direntry
}
type DirList struct {
MaxHeight int // directory tree height, > 0
List []DirEntry
}
// hasThirdParty checks whether a list of directory entries has packages outside
// the standard library or not.
func hasThirdParty(list []DirEntry) bool {
for _, entry := range list {
if entry.RootType == vfs.RootTypeGoPath {
return true
}
}
return false
}
// listing creates a (linear) directory listing from a directory tree.
// If skipRoot is set, the root directory itself is excluded from the list.
// If filter is set, only the directory entries whose paths match the filter
// are included.
//
func (dir *Directory) listing(skipRoot bool, filter func(string) bool) *DirList {
if dir == nil {
return nil
}
// determine number of entries n and maximum height
n := 0
minDepth := 1 << 30 // infinity
maxDepth := 0
for d := range dir.iter(skipRoot) {
n++
if minDepth > d.Depth {
minDepth = d.Depth
}
if maxDepth < d.Depth {
maxDepth = d.Depth
}
}
maxHeight := maxDepth - minDepth + 1
if n == 0 {
return nil
}
// create list
list := make([]DirEntry, 0, n)
for d := range dir.iter(skipRoot) {
if filter != nil && !filter(d.Path) {
continue
}
var p DirEntry
p.Depth = d.Depth - minDepth
p.Height = maxHeight - p.Depth
// 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, dir.Path)
// remove leading separator if any - path must be relative
path = strings.TrimPrefix(path, "/")
p.Path = path
p.Name = d.Name
p.HasPkg = d.HasPkg
p.Synopsis = d.Synopsis
p.RootType = d.RootType
list = append(list, p)
}
return &DirList{maxHeight, list}
}