Current File : //usr/local/go/src/cmd/compile/internal/noder/import.go
// Copyright 2009 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 noder
import (
"errors"
"fmt"
"internal/buildcfg"
"io"
"os"
pathpkg "path"
"runtime"
"sort"
"strconv"
"strings"
"unicode"
"unicode/utf8"
"cmd/compile/internal/base"
"cmd/compile/internal/importer"
"cmd/compile/internal/ir"
"cmd/compile/internal/syntax"
"cmd/compile/internal/typecheck"
"cmd/compile/internal/types"
"cmd/compile/internal/types2"
"cmd/internal/archive"
"cmd/internal/bio"
"cmd/internal/goobj"
"cmd/internal/objabi"
"cmd/internal/src"
)
// Temporary import helper to get type2-based type-checking going.
type gcimports struct {
packages map[string]*types2.Package
}
func (m *gcimports) Import(path string) (*types2.Package, error) {
return m.ImportFrom(path, "" /* no vendoring */, 0)
}
func (m *gcimports) ImportFrom(path, srcDir string, mode types2.ImportMode) (*types2.Package, error) {
if mode != 0 {
panic("mode must be 0")
}
path, err := resolveImportPath(path)
if err != nil {
return nil, err
}
lookup := func(path string) (io.ReadCloser, error) { return openPackage(path) }
return importer.Import(m.packages, path, srcDir, lookup)
}
func isDriveLetter(b byte) bool {
return 'a' <= b && b <= 'z' || 'A' <= b && b <= 'Z'
}
// is this path a local name? begins with ./ or ../ or /
func islocalname(name string) bool {
return strings.HasPrefix(name, "/") ||
runtime.GOOS == "windows" && len(name) >= 3 && isDriveLetter(name[0]) && name[1] == ':' && name[2] == '/' ||
strings.HasPrefix(name, "./") || name == "." ||
strings.HasPrefix(name, "../") || name == ".."
}
func openPackage(path string) (*os.File, error) {
if islocalname(path) {
if base.Flag.NoLocalImports {
return nil, errors.New("local imports disallowed")
}
if base.Flag.Cfg.PackageFile != nil {
return os.Open(base.Flag.Cfg.PackageFile[path])
}
// try .a before .o. important for building libraries:
// if there is an array.o in the array.a library,
// want to find all of array.a, not just array.o.
if file, err := os.Open(fmt.Sprintf("%s.a", path)); err == nil {
return file, nil
}
if file, err := os.Open(fmt.Sprintf("%s.o", path)); err == nil {
return file, nil
}
return nil, errors.New("file not found")
}
// local imports should be canonicalized already.
// don't want to see "encoding/../encoding/base64"
// as different from "encoding/base64".
if q := pathpkg.Clean(path); q != path {
return nil, fmt.Errorf("non-canonical import path %q (should be %q)", path, q)
}
if base.Flag.Cfg.PackageFile != nil {
return os.Open(base.Flag.Cfg.PackageFile[path])
}
for _, dir := range base.Flag.Cfg.ImportDirs {
if file, err := os.Open(fmt.Sprintf("%s/%s.a", dir, path)); err == nil {
return file, nil
}
if file, err := os.Open(fmt.Sprintf("%s/%s.o", dir, path)); err == nil {
return file, nil
}
}
if buildcfg.GOROOT != "" {
suffix := ""
if base.Flag.InstallSuffix != "" {
suffix = "_" + base.Flag.InstallSuffix
} else if base.Flag.Race {
suffix = "_race"
} else if base.Flag.MSan {
suffix = "_msan"
}
if file, err := os.Open(fmt.Sprintf("%s/pkg/%s_%s%s/%s.a", buildcfg.GOROOT, buildcfg.GOOS, buildcfg.GOARCH, suffix, path)); err == nil {
return file, nil
}
if file, err := os.Open(fmt.Sprintf("%s/pkg/%s_%s%s/%s.o", buildcfg.GOROOT, buildcfg.GOOS, buildcfg.GOARCH, suffix, path)); err == nil {
return file, nil
}
}
return nil, errors.New("file not found")
}
// myheight tracks the local package's height based on packages
// imported so far.
var myheight int
// resolveImportPath resolves an import path as it appears in a Go
// source file to the package's full path.
func resolveImportPath(path string) (string, error) {
// The package name main is no longer reserved,
// but we reserve the import path "main" to identify
// the main package, just as we reserve the import
// path "math" to identify the standard math package.
if path == "main" {
return "", errors.New("cannot import \"main\"")
}
if base.Ctxt.Pkgpath != "" && path == base.Ctxt.Pkgpath {
return "", fmt.Errorf("import %q while compiling that package (import cycle)", path)
}
if mapped, ok := base.Flag.Cfg.ImportMap[path]; ok {
path = mapped
}
if islocalname(path) {
if path[0] == '/' {
return "", errors.New("import path cannot be absolute path")
}
prefix := base.Flag.D
if prefix == "" {
// Questionable, but when -D isn't specified, historically we
// resolve local import paths relative to the directory the
// compiler's current directory, not the respective source
// file's directory.
prefix = base.Ctxt.Pathname
}
path = pathpkg.Join(prefix, path)
if err := checkImportPath(path, true); err != nil {
return "", err
}
}
return path, nil
}
// TODO(mdempsky): Return an error instead.
func importfile(decl *syntax.ImportDecl) *types.Pkg {
if decl.Path.Kind != syntax.StringLit {
base.Errorf("import path must be a string")
return nil
}
path, err := strconv.Unquote(decl.Path.Value)
if err != nil {
base.Errorf("import path must be a string")
return nil
}
if err := checkImportPath(path, false); err != nil {
base.Errorf("%s", err.Error())
return nil
}
path, err = resolveImportPath(path)
if err != nil {
base.Errorf("%s", err)
return nil
}
importpkg := types.NewPkg(path, "")
if importpkg.Direct {
return importpkg // already fully loaded
}
importpkg.Direct = true
typecheck.Target.Imports = append(typecheck.Target.Imports, importpkg)
if path == "unsafe" {
return importpkg // initialized with universe
}
f, err := openPackage(path)
if err != nil {
base.Errorf("could not import %q: %v", path, err)
base.ErrorExit()
}
imp := bio.NewReader(f)
defer imp.Close()
file := f.Name()
// check object header
p, err := imp.ReadString('\n')
if err != nil {
base.Errorf("import %s: reading input: %v", file, err)
base.ErrorExit()
}
if p == "!<arch>\n" { // package archive
// package export block should be first
sz := archive.ReadHeader(imp.Reader, "__.PKGDEF")
if sz <= 0 {
base.Errorf("import %s: not a package file", file)
base.ErrorExit()
}
p, err = imp.ReadString('\n')
if err != nil {
base.Errorf("import %s: reading input: %v", file, err)
base.ErrorExit()
}
}
if !strings.HasPrefix(p, "go object ") {
base.Errorf("import %s: not a go object file: %s", file, p)
base.ErrorExit()
}
q := objabi.HeaderString()
if p != q {
base.Errorf("import %s: object is [%s] expected [%s]", file, p, q)
base.ErrorExit()
}
// process header lines
for {
p, err = imp.ReadString('\n')
if err != nil {
base.Errorf("import %s: reading input: %v", file, err)
base.ErrorExit()
}
if p == "\n" {
break // header ends with blank line
}
}
// Expect $$B\n to signal binary import format.
// look for $$
var c byte
for {
c, err = imp.ReadByte()
if err != nil {
break
}
if c == '$' {
c, err = imp.ReadByte()
if c == '$' || err != nil {
break
}
}
}
// get character after $$
if err == nil {
c, _ = imp.ReadByte()
}
var fingerprint goobj.FingerprintType
switch c {
case '\n':
base.Errorf("cannot import %s: old export format no longer supported (recompile library)", path)
return nil
case 'B':
if base.Debug.Export != 0 {
fmt.Printf("importing %s (%s)\n", path, file)
}
imp.ReadByte() // skip \n after $$B
c, err = imp.ReadByte()
if err != nil {
base.Errorf("import %s: reading input: %v", file, err)
base.ErrorExit()
}
// Indexed format is distinguished by an 'i' byte,
// whereas previous export formats started with 'c', 'd', or 'v'.
if c != 'i' {
base.Errorf("import %s: unexpected package format byte: %v", file, c)
base.ErrorExit()
}
fingerprint = typecheck.ReadImports(importpkg, imp)
default:
base.Errorf("no import in %q", path)
base.ErrorExit()
}
// assume files move (get installed) so don't record the full path
if base.Flag.Cfg.PackageFile != nil {
// If using a packageFile map, assume path_ can be recorded directly.
base.Ctxt.AddImport(path, fingerprint)
} else {
// For file "/Users/foo/go/pkg/darwin_amd64/math.a" record "math.a".
base.Ctxt.AddImport(file[len(file)-len(path)-len(".a"):], fingerprint)
}
if importpkg.Height >= myheight {
myheight = importpkg.Height + 1
}
return importpkg
}
// The linker uses the magic symbol prefixes "go." and "type."
// Avoid potential confusion between import paths and symbols
// by rejecting these reserved imports for now. Also, people
// "can do weird things in GOPATH and we'd prefer they didn't
// do _that_ weird thing" (per rsc). See also #4257.
var reservedimports = []string{
"go",
"type",
}
func checkImportPath(path string, allowSpace bool) error {
if path == "" {
return errors.New("import path is empty")
}
if strings.Contains(path, "\x00") {
return errors.New("import path contains NUL")
}
for _, ri := range reservedimports {
if path == ri {
return fmt.Errorf("import path %q is reserved and cannot be used", path)
}
}
for _, r := range path {
switch {
case r == utf8.RuneError:
return fmt.Errorf("import path contains invalid UTF-8 sequence: %q", path)
case r < 0x20 || r == 0x7f:
return fmt.Errorf("import path contains control character: %q", path)
case r == '\\':
return fmt.Errorf("import path contains backslash; use slash: %q", path)
case !allowSpace && unicode.IsSpace(r):
return fmt.Errorf("import path contains space character: %q", path)
case strings.ContainsRune("!\"#$%&'()*,:;<=>?[]^`{|}", r):
return fmt.Errorf("import path contains invalid character '%c': %q", r, path)
}
}
return nil
}
func pkgnotused(lineno src.XPos, path string, name string) {
// If the package was imported with a name other than the final
// import path element, show it explicitly in the error message.
// Note that this handles both renamed imports and imports of
// packages containing unconventional package declarations.
// Note that this uses / always, even on Windows, because Go import
// paths always use forward slashes.
elem := path
if i := strings.LastIndex(elem, "/"); i >= 0 {
elem = elem[i+1:]
}
if name == "" || elem == name {
base.ErrorfAt(lineno, "imported and not used: %q", path)
} else {
base.ErrorfAt(lineno, "imported and not used: %q as %s", path, name)
}
}
func mkpackage(pkgname string) {
if types.LocalPkg.Name == "" {
if pkgname == "_" {
base.Errorf("invalid package name _")
}
types.LocalPkg.Name = pkgname
} else {
if pkgname != types.LocalPkg.Name {
base.Errorf("package %s; expected %s", pkgname, types.LocalPkg.Name)
}
}
}
func clearImports() {
type importedPkg struct {
pos src.XPos
path string
name string
}
var unused []importedPkg
for _, s := range types.LocalPkg.Syms {
n := ir.AsNode(s.Def)
if n == nil {
continue
}
if n.Op() == ir.OPACK {
// throw away top-level package name left over
// from previous file.
// leave s->block set to cause redeclaration
// errors if a conflicting top-level name is
// introduced by a different file.
p := n.(*ir.PkgName)
if !p.Used && base.SyntaxErrors() == 0 {
unused = append(unused, importedPkg{p.Pos(), p.Pkg.Path, s.Name})
}
s.Def = nil
continue
}
if types.IsDotAlias(s) {
// throw away top-level name left over
// from previous import . "x"
// We'll report errors after type checking in CheckDotImports.
s.Def = nil
continue
}
}
sort.Slice(unused, func(i, j int) bool { return unused[i].pos.Before(unused[j].pos) })
for _, pkg := range unused {
pkgnotused(pkg.pos, pkg.path, pkg.name)
}
}
// CheckDotImports reports errors for any unused dot imports.
func CheckDotImports() {
for _, pack := range dotImports {
if !pack.Used {
base.ErrorfAt(pack.Pos(), "imported and not used: %q", pack.Pkg.Path)
}
}
// No longer needed; release memory.
dotImports = nil
typecheck.DotImportRefs = nil
}
// dotImports tracks all PkgNames that have been dot-imported.
var dotImports []*ir.PkgName
// find all the exported symbols in package referenced by PkgName,
// and make them available in the current package
func importDot(pack *ir.PkgName) {
if typecheck.DotImportRefs == nil {
typecheck.DotImportRefs = make(map[*ir.Ident]*ir.PkgName)
}
opkg := pack.Pkg
for _, s := range opkg.Syms {
if s.Def == nil {
if _, ok := typecheck.DeclImporter[s]; !ok {
continue
}
}
if !types.IsExported(s.Name) || strings.ContainsRune(s.Name, 0xb7) { // 0xb7 = center dot
continue
}
s1 := typecheck.Lookup(s.Name)
if s1.Def != nil {
pkgerror := fmt.Sprintf("during import %q", opkg.Path)
typecheck.Redeclared(base.Pos, s1, pkgerror)
continue
}
id := ir.NewIdent(src.NoXPos, s)
typecheck.DotImportRefs[id] = pack
s1.Def = id
s1.Block = 1
}
dotImports = append(dotImports, pack)
}
// importName is like oldname,
// but it reports an error if sym is from another package and not exported.
func importName(sym *types.Sym) ir.Node {
n := oldname(sym)
if !types.IsExported(sym.Name) && sym.Pkg != types.LocalPkg {
n.SetDiag(true)
base.Errorf("cannot refer to unexported name %s.%s", sym.Pkg.Name, sym.Name)
}
return n
}
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