1 // Copyright 2017 The Go Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style 3 // license that can be found in the LICENSE file. 4 5 package types 6 7 import ( 8 "cmd/internal/obj" 9 "cmd/internal/objabi" 10 "fmt" 11 "sort" 12 "sync" 13 ) 14 15 // pkgMap maps a package path to a package. 16 var pkgMap = make(map[string]*Pkg) 17 18 type Pkg struct { 19 Path string // string literal used in import statement, e.g. "runtime/internal/sys" 20 Name string // package name, e.g. "sys" 21 Pathsym *obj.LSym 22 Prefix string // escaped path for use in symbol table 23 Imported bool // export data of this package was parsed 24 Direct bool // imported directly 25 Syms map[string]*Sym 26 } 27 28 // NewPkg returns a new Pkg for the given package path and name. 29 // Unless name is the empty string, if the package exists already, 30 // the existing package name and the provided name must match. 31 func NewPkg(path, name string) *Pkg { 32 if p := pkgMap[path]; p != nil { 33 if name != "" && p.Name != name { 34 panic(fmt.Sprintf("conflicting package names %s and %s for path %q", p.Name, name, path)) 35 } 36 return p 37 } 38 39 p := new(Pkg) 40 p.Path = path 41 p.Name = name 42 p.Prefix = objabi.PathToPrefix(path) 43 p.Syms = make(map[string]*Sym) 44 pkgMap[path] = p 45 46 return p 47 } 48 49 // ImportedPkgList returns the list of directly imported packages. 50 // The list is sorted by package path. 51 func ImportedPkgList() []*Pkg { 52 var list []*Pkg 53 for _, p := range pkgMap { 54 if p.Direct { 55 list = append(list, p) 56 } 57 } 58 sort.Sort(byPath(list)) 59 return list 60 } 61 62 type byPath []*Pkg 63 64 func (a byPath) Len() int { return len(a) } 65 func (a byPath) Less(i, j int) bool { return a[i].Path < a[j].Path } 66 func (a byPath) Swap(i, j int) { a[i], a[j] = a[j], a[i] } 67 68 var nopkg = &Pkg{ 69 Syms: make(map[string]*Sym), 70 } 71 72 func (pkg *Pkg) Lookup(name string) *Sym { 73 s, _ := pkg.LookupOK(name) 74 return s 75 } 76 77 var InitSyms []*Sym 78 79 // LookupOK looks up name in pkg and reports whether it previously existed. 80 func (pkg *Pkg) LookupOK(name string) (s *Sym, existed bool) { 81 // TODO(gri) remove this check in favor of specialized lookup 82 if pkg == nil { 83 pkg = nopkg 84 } 85 if s := pkg.Syms[name]; s != nil { 86 return s, true 87 } 88 89 s = &Sym{ 90 Name: name, 91 Pkg: pkg, 92 } 93 if name == "init" { 94 InitSyms = append(InitSyms, s) 95 } 96 pkg.Syms[name] = s 97 return s, false 98 } 99 100 func (pkg *Pkg) LookupBytes(name []byte) *Sym { 101 // TODO(gri) remove this check in favor of specialized lookup 102 if pkg == nil { 103 pkg = nopkg 104 } 105 if s := pkg.Syms[string(name)]; s != nil { 106 return s 107 } 108 str := InternString(name) 109 return pkg.Lookup(str) 110 } 111 112 var ( 113 internedStringsmu sync.Mutex // protects internedStrings 114 internedStrings = map[string]string{} 115 ) 116 117 func InternString(b []byte) string { 118 internedStringsmu.Lock() 119 s, ok := internedStrings[string(b)] // string(b) here doesn't allocate 120 if !ok { 121 s = string(b) 122 internedStrings[s] = s 123 } 124 internedStringsmu.Unlock() 125 return s 126 } 127 128 // CleanroomDo invokes f in an environment with with no preexisting packages. 129 // For testing of import/export only. 130 func CleanroomDo(f func()) { 131 saved := pkgMap 132 pkgMap = make(map[string]*Pkg) 133 f() 134 pkgMap = saved 135 } 136
