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// Copyright 2013 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.
package godoc
import (
"fmt"
"go/ast"
"go/build"
"io"
"log"
"os"
pathpkg "path"
"path/filepath"
"regexp"
"strings"
"golang.org/x/tools/godoc/vfs"
)
const (
target = "/target"
cmdPrefix = "cmd/"
srcPrefix = "src/"
toolsPath = "golang.org/x/tools/cmd/"
)
// CommandLine returns godoc results to w.
// Note that it may add a /target path to fs.
func CommandLine(w io.Writer, fs vfs.NameSpace, pres *Presentation, args []string) error {
path := args[0]
srcMode := pres.SrcMode
cmdMode := strings.HasPrefix(path, cmdPrefix)
if strings.HasPrefix(path, srcPrefix) {
path = strings.TrimPrefix(path, srcPrefix)
srcMode = true
}
var abspath, relpath string
if cmdMode {
path = strings.TrimPrefix(path, cmdPrefix)
} else {
abspath, relpath = paths(fs, pres, path)
}
var mode PageInfoMode
if relpath == builtinPkgPath {
// the fake built-in package contains unexported identifiers
mode = NoFiltering | NoTypeAssoc
}
if srcMode {
// only filter exports if we don't have explicit command-line filter arguments
if len(args) > 1 {
mode |= NoFiltering
}
mode |= ShowSource
}
// First, try as package unless forced as command.
var info *PageInfo
if !cmdMode {
info = pres.GetPkgPageInfo(abspath, relpath, mode)
}
// Second, try as command (if the path is not absolute).
var cinfo *PageInfo
if !filepath.IsAbs(path) {
// First try go.tools/cmd.
abspath = pathpkg.Join(pres.PkgFSRoot(), toolsPath+path)
cinfo = pres.GetCmdPageInfo(abspath, relpath, mode)
if cinfo.IsEmpty() {
// Then try $GOROOT/cmd.
abspath = pathpkg.Join(pres.CmdFSRoot(), path)
cinfo = pres.GetCmdPageInfo(abspath, relpath, mode)
}
}
// determine what to use
if info == nil || info.IsEmpty() {
if cinfo != nil && !cinfo.IsEmpty() {
// only cinfo exists - switch to cinfo
info = cinfo
}
} else if cinfo != nil && !cinfo.IsEmpty() {
// both info and cinfo exist - use cinfo if info
// contains only subdirectory information
if info.PAst == nil && info.PDoc == nil {
info = cinfo
} else if relpath != target {
// The above check handles the case where an operating system path
// is provided (see documentation for paths below). In that case,
// relpath is set to "/target" (in anticipation of accessing packages there),
// and is therefore not expected to match a command.
fmt.Fprintf(w, "use 'godoc %s%s' for documentation on the %s command \n\n", cmdPrefix, relpath, relpath)
}
}
if info == nil {
return fmt.Errorf("%s: no such directory or package", args[0])
}
if info.Err != nil {
return info.Err
}
if info.PDoc != nil && info.PDoc.ImportPath == target {
// Replace virtual /target with actual argument from command line.
info.PDoc.ImportPath = args[0]
}
// If we have more than one argument, use the remaining arguments for filtering.
if len(args) > 1 {
info.IsFiltered = true
filterInfo(args[1:], info)
}
packageText := pres.PackageText
if pres.HTMLMode {
packageText = pres.PackageHTML
}
if err := packageText.Execute(w, info); err != nil {
return err
}
return nil
}
// paths determines the paths to use.
//
// If we are passed an operating system path like . or ./foo or /foo/bar or c:\mysrc,
// we need to map that path somewhere in the fs name space so that routines
// like getPageInfo will see it. We use the arbitrarily-chosen virtual path "/target"
// for this. That is, if we get passed a directory like the above, we map that
// directory so that getPageInfo sees it as /target.
// Returns the absolute and relative paths.
func paths(fs vfs.NameSpace, pres *Presentation, path string) (string, string) {
if filepath.IsAbs(path) {
fs.Bind(target, vfs.OS(path), "/", vfs.BindReplace)
return target, target
}
if build.IsLocalImport(path) {
cwd, _ := os.Getwd() // ignore errors
path = filepath.Join(cwd, path)
fs.Bind(target, vfs.OS(path), "/", vfs.BindReplace)
return target, target
}
if bp, _ := build.Import(path, "", build.FindOnly); bp.Dir != "" && bp.ImportPath != "" {
fs.Bind(target, vfs.OS(bp.Dir), "/", vfs.BindReplace)
return target, bp.ImportPath
}
return pathpkg.Join(pres.PkgFSRoot(), path), path
}
// filterInfo updates info to include only the nodes that match the given
// filter args.
func filterInfo(args []string, info *PageInfo) {
rx, err := makeRx(args)
if err != nil {
log.Fatalf("illegal regular expression from %v: %v", args, err)
}
filter := func(s string) bool { return rx.MatchString(s) }
switch {
case info.PAst != nil:
newPAst := map[string]*ast.File{}
for name, a := range info.PAst {
cmap := ast.NewCommentMap(info.FSet, a, a.Comments)
a.Comments = []*ast.CommentGroup{} // remove all comments.
ast.FilterFile(a, filter)
if len(a.Decls) > 0 {
newPAst[name] = a
}
for _, d := range a.Decls {
// add back the comments associated with d only
comments := cmap.Filter(d).Comments()
a.Comments = append(a.Comments, comments...)
}
}
info.PAst = newPAst // add only matching files.
case info.PDoc != nil:
info.PDoc.Filter(filter)
}
}
// Does s look like a regular expression?
func isRegexp(s string) bool {
return strings.ContainsAny(s, ".(|)*+?^$[]")
}
// Make a regular expression of the form
// names[0]|names[1]|...names[len(names)-1].
// Returns an error if the regular expression is illegal.
func makeRx(names []string) (*regexp.Regexp, error) {
if len(names) == 0 {
return nil, fmt.Errorf("no expression provided")
}
s := ""
for i, name := range names {
if i > 0 {
s += "|"
}
if isRegexp(name) {
s += name
} else {
s += "^" + name + "$" // must match exactly
}
}
return regexp.Compile(s)
}