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 srcimporter implements importing directly 6// from source files rather than installed packages. 7package srcimporter // import "go/internal/srcimporter" 8 9import ( 10 "fmt" 11 "go/ast" 12 "go/build" 13 "go/parser" 14 "go/token" 15 "go/types" 16 "io" 17 "os" 18 "os/exec" 19 "path/filepath" 20 "strings" 21 "sync" 22 _ "unsafe" // for go:linkname 23) 24 25// An Importer provides the context for importing packages from source code. 26type Importer struct { 27 ctxt *build.Context 28 fset *token.FileSet 29 sizes types.Sizes 30 packages map[string]*types.Package 31} 32 33// New returns a new Importer for the given context, file set, and map 34// of packages. The context is used to resolve import paths to package paths, 35// and identifying the files belonging to the package. If the context provides 36// non-nil file system functions, they are used instead of the regular package 37// os functions. The file set is used to track position information of package 38// files; and imported packages are added to the packages map. 39func New(ctxt *build.Context, fset *token.FileSet, packages map[string]*types.Package) *Importer { 40 return &Importer{ 41 ctxt: ctxt, 42 fset: fset, 43 sizes: types.SizesFor(ctxt.Compiler, ctxt.GOARCH), // uses go/types default if GOARCH not found 44 packages: packages, 45 } 46} 47 48// Importing is a sentinel taking the place in Importer.packages 49// for a package that is in the process of being imported. 50var importing types.Package 51 52// Import(path) is a shortcut for ImportFrom(path, ".", 0). 53func (p *Importer) Import(path string) (*types.Package, error) { 54 return p.ImportFrom(path, ".", 0) // use "." rather than "" (see issue #24441) 55} 56 57// ImportFrom imports the package with the given import path resolved from the given srcDir, 58// adds the new package to the set of packages maintained by the importer, and returns the 59// package. Package path resolution and file system operations are controlled by the context 60// maintained with the importer. The import mode must be zero but is otherwise ignored. 61// Packages that are not comprised entirely of pure Go files may fail to import because the 62// type checker may not be able to determine all exported entities (e.g. due to cgo dependencies). 63func (p *Importer) ImportFrom(path, srcDir string, mode types.ImportMode) (*types.Package, error) { 64 if mode != 0 { 65 panic("non-zero import mode") 66 } 67 68 if abs, err := p.absPath(srcDir); err == nil { // see issue #14282 69 srcDir = abs 70 } 71 bp, err := p.ctxt.Import(path, srcDir, 0) 72 if err != nil { 73 return nil, err // err may be *build.NoGoError - return as is 74 } 75 76 // package unsafe is known to the type checker 77 if bp.ImportPath == "unsafe" { 78 return types.Unsafe, nil 79 } 80 81 // no need to re-import if the package was imported completely before 82 pkg := p.packages[bp.ImportPath] 83 if pkg != nil { 84 if pkg == &importing { 85 return nil, fmt.Errorf("import cycle through package %q", bp.ImportPath) 86 } 87 if !pkg.Complete() { 88 // Package exists but is not complete - we cannot handle this 89 // at the moment since the source importer replaces the package 90 // wholesale rather than augmenting it (see #19337 for details). 91 // Return incomplete package with error (see #16088). 92 return pkg, fmt.Errorf("reimported partially imported package %q", bp.ImportPath) 93 } 94 return pkg, nil 95 } 96 97 p.packages[bp.ImportPath] = &importing 98 defer func() { 99 // clean up in case of error 100 // TODO(gri) Eventually we may want to leave a (possibly empty) 101 // package in the map in all cases (and use that package to 102 // identify cycles). See also issue 16088. 103 if p.packages[bp.ImportPath] == &importing { 104 p.packages[bp.ImportPath] = nil 105 } 106 }() 107 108 var filenames []string 109 filenames = append(filenames, bp.GoFiles...) 110 filenames = append(filenames, bp.CgoFiles...) 111 112 files, err := p.parseFiles(bp.Dir, filenames) 113 if err != nil { 114 return nil, err 115 } 116 117 // type-check package files 118 var firstHardErr error 119 conf := types.Config{ 120 IgnoreFuncBodies: true, 121 // continue type-checking after the first error 122 Error: func(err error) { 123 if firstHardErr == nil && !err.(types.Error).Soft { 124 firstHardErr = err 125 } 126 }, 127 Importer: p, 128 Sizes: p.sizes, 129 } 130 if len(bp.CgoFiles) > 0 { 131 if p.ctxt.OpenFile != nil { 132 // cgo, gcc, pkg-config, etc. do not support 133 // build.Context's VFS. 134 conf.FakeImportC = true 135 } else { 136 setUsesCgo(&conf) 137 file, err := p.cgo(bp) 138 if err != nil { 139 return nil, fmt.Errorf("error processing cgo for package %q: %w", bp.ImportPath, err) 140 } 141 files = append(files, file) 142 } 143 } 144 145 pkg, err = conf.Check(bp.ImportPath, p.fset, files, nil) 146 if err != nil { 147 // If there was a hard error it is possibly unsafe 148 // to use the package as it may not be fully populated. 149 // Do not return it (see also #20837, #20855). 150 if firstHardErr != nil { 151 pkg = nil 152 err = firstHardErr // give preference to first hard error over any soft error 153 } 154 return pkg, fmt.Errorf("type-checking package %q failed (%v)", bp.ImportPath, err) 155 } 156 if firstHardErr != nil { 157 // this can only happen if we have a bug in go/types 158 panic("package is not safe yet no error was returned") 159 } 160 161 p.packages[bp.ImportPath] = pkg 162 return pkg, nil 163} 164 165func (p *Importer) parseFiles(dir string, filenames []string) ([]*ast.File, error) { 166 // use build.Context's OpenFile if there is one 167 open := p.ctxt.OpenFile 168 if open == nil { 169 open = func(name string) (io.ReadCloser, error) { return os.Open(name) } 170 } 171 172 files := make([]*ast.File, len(filenames)) 173 errors := make([]error, len(filenames)) 174 175 var wg sync.WaitGroup 176 wg.Add(len(filenames)) 177 for i, filename := range filenames { 178 go func(i int, filepath string) { 179 defer wg.Done() 180 src, err := open(filepath) 181 if err != nil { 182 errors[i] = err // open provides operation and filename in error 183 return 184 } 185 files[i], errors[i] = parser.ParseFile(p.fset, filepath, src, parser.SkipObjectResolution) 186 src.Close() // ignore Close error - parsing may have succeeded which is all we need 187 }(i, p.joinPath(dir, filename)) 188 } 189 wg.Wait() 190 191 // if there are errors, return the first one for deterministic results 192 for _, err := range errors { 193 if err != nil { 194 return nil, err 195 } 196 } 197 198 return files, nil 199} 200 201func (p *Importer) cgo(bp *build.Package) (*ast.File, error) { 202 tmpdir, err := os.MkdirTemp("", "srcimporter") 203 if err != nil { 204 return nil, err 205 } 206 defer os.RemoveAll(tmpdir) 207 208 goCmd := "go" 209 if p.ctxt.GOROOT != "" { 210 goCmd = filepath.Join(p.ctxt.GOROOT, "bin", "go") 211 } 212 args := []string{goCmd, "tool", "cgo", "-objdir", tmpdir} 213 if bp.Goroot { 214 switch bp.ImportPath { 215 case "runtime/cgo": 216 args = append(args, "-import_runtime_cgo=false", "-import_syscall=false") 217 case "runtime/race": 218 args = append(args, "-import_syscall=false") 219 } 220 } 221 args = append(args, "--") 222 args = append(args, strings.Fields(os.Getenv("CGO_CPPFLAGS"))...) 223 args = append(args, bp.CgoCPPFLAGS...) 224 if len(bp.CgoPkgConfig) > 0 { 225 cmd := exec.Command("pkg-config", append([]string{"--cflags"}, bp.CgoPkgConfig...)...) 226 out, err := cmd.Output() 227 if err != nil { 228 return nil, fmt.Errorf("pkg-config --cflags: %w", err) 229 } 230 args = append(args, strings.Fields(string(out))...) 231 } 232 args = append(args, "-I", tmpdir) 233 args = append(args, strings.Fields(os.Getenv("CGO_CFLAGS"))...) 234 args = append(args, bp.CgoCFLAGS...) 235 args = append(args, bp.CgoFiles...) 236 237 cmd := exec.Command(args[0], args[1:]...) 238 cmd.Dir = bp.Dir 239 if err := cmd.Run(); err != nil { 240 return nil, fmt.Errorf("go tool cgo: %w", err) 241 } 242 243 return parser.ParseFile(p.fset, filepath.Join(tmpdir, "_cgo_gotypes.go"), nil, parser.SkipObjectResolution) 244} 245 246// context-controlled file system operations 247 248func (p *Importer) absPath(path string) (string, error) { 249 // TODO(gri) This should be using p.ctxt.AbsPath which doesn't 250 // exist but probably should. See also issue #14282. 251 return filepath.Abs(path) 252} 253 254func (p *Importer) isAbsPath(path string) bool { 255 if f := p.ctxt.IsAbsPath; f != nil { 256 return f(path) 257 } 258 return filepath.IsAbs(path) 259} 260 261func (p *Importer) joinPath(elem ...string) string { 262 if f := p.ctxt.JoinPath; f != nil { 263 return f(elem...) 264 } 265 return filepath.Join(elem...) 266} 267 268//go:linkname setUsesCgo go/types.srcimporter_setUsesCgo 269func setUsesCgo(conf *types.Config) 270