--- /dev/null
+// Copyright 2011 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 build
+
+import (
+ "bytes"
+ "errors"
+ "fmt"
+ "go/ast"
+ "go/build/constraint"
+ "go/doc"
+ "go/token"
+ "internal/buildcfg"
+ "internal/goroot"
+ "internal/goversion"
+ "io"
+ "io/fs"
+ "os"
+ "os/exec"
+ pathpkg "path"
+ "path/filepath"
+ "runtime"
+ "sort"
+ "strconv"
+ "strings"
+ "unicode"
+ "unicode/utf8"
+)
+
+// A Context specifies the supporting context for a build.
+type Context struct {
+ GOARCH string // target architecture
+ GOOS string // target operating system
+ GOROOT string // Go root
+ GOPATH string // Go paths
+
+ // Dir is the caller's working directory, or the empty string to use
+ // the current directory of the running process. In module mode, this is used
+ // to locate the main module.
+ //
+ // If Dir is non-empty, directories passed to Import and ImportDir must
+ // be absolute.
+ Dir string
+
+ CgoEnabled bool // whether cgo files are included
+ UseAllFiles bool // use files regardless of +build lines, file names
+ Compiler string // compiler to assume when computing target paths
+
+ // The build, tool, and release tags specify build constraints
+ // that should be considered satisfied when processing +build lines.
+ // Clients creating a new context may customize BuildTags, which
+ // defaults to empty, but it is usually an error to customize ToolTags or ReleaseTags.
+ // ToolTags defaults to build tags appropriate to the current Go toolchain configuration.
+ // ReleaseTags defaults to the list of Go releases the current release is compatible with.
+ // BuildTags is not set for the Default build Context.
+ // In addition to the BuildTags, ToolTags, and ReleaseTags, build constraints
+ // consider the values of GOARCH and GOOS as satisfied tags.
+ // The last element in ReleaseTags is assumed to be the current release.
+ BuildTags []string
+ ToolTags []string
+ ReleaseTags []string
+
+ // The install suffix specifies a suffix to use in the name of the installation
+ // directory. By default it is empty, but custom builds that need to keep
+ // their outputs separate can set InstallSuffix to do so. For example, when
+ // using the race detector, the go command uses InstallSuffix = "race", so
+ // that on a Linux/386 system, packages are written to a directory named
+ // "linux_386_race" instead of the usual "linux_386".
+ InstallSuffix string
+
+ // By default, Import uses the operating system's file system calls
+ // to read directories and files. To read from other sources,
+ // callers can set the following functions. They all have default
+ // behaviors that use the local file system, so clients need only set
+ // the functions whose behaviors they wish to change.
+
+ // JoinPath joins the sequence of path fragments into a single path.
+ // If JoinPath is nil, Import uses filepath.Join.
+ JoinPath func(elem ...string) string
+
+ // SplitPathList splits the path list into a slice of individual paths.
+ // If SplitPathList is nil, Import uses filepath.SplitList.
+ SplitPathList func(list string) []string
+
+ // IsAbsPath reports whether path is an absolute path.
+ // If IsAbsPath is nil, Import uses filepath.IsAbs.
+ IsAbsPath func(path string) bool
+
+ // IsDir reports whether the path names a directory.
+ // If IsDir is nil, Import calls os.Stat and uses the result's IsDir method.
+ IsDir func(path string) bool
+
+ // HasSubdir reports whether dir is lexically a subdirectory of
+ // root, perhaps multiple levels below. It does not try to check
+ // whether dir exists.
+ // If so, HasSubdir sets rel to a slash-separated path that
+ // can be joined to root to produce a path equivalent to dir.
+ // If HasSubdir is nil, Import uses an implementation built on
+ // filepath.EvalSymlinks.
+ HasSubdir func(root, dir string) (rel string, ok bool)
+
+ // ReadDir returns a slice of fs.FileInfo, sorted by Name,
+ // describing the content of the named directory.
+ // If ReadDir is nil, Import uses ioutil.ReadDir.
+ ReadDir func(dir string) ([]fs.FileInfo, error)
+
+ // OpenFile opens a file (not a directory) for reading.
+ // If OpenFile is nil, Import uses os.Open.
+ OpenFile func(path string) (io.ReadCloser, error)
+}
+
+// joinPath calls ctxt.JoinPath (if not nil) or else filepath.Join.
+func (ctxt *Context) joinPath(elem ...string) string {
+ if f := ctxt.JoinPath; f != nil {
+ return f(elem...)
+ }
+ return filepath.Join(elem...)
+}
+
+// splitPathList calls ctxt.SplitPathList (if not nil) or else filepath.SplitList.
+func (ctxt *Context) splitPathList(s string) []string {
+ if f := ctxt.SplitPathList; f != nil {
+ return f(s)
+ }
+ return filepath.SplitList(s)
+}
+
+// isAbsPath calls ctxt.IsAbsPath (if not nil) or else filepath.IsAbs.
+func (ctxt *Context) isAbsPath(path string) bool {
+ if f := ctxt.IsAbsPath; f != nil {
+ return f(path)
+ }
+ return filepath.IsAbs(path)
+}
+
+// isDir calls ctxt.IsDir (if not nil) or else uses os.Stat.
+func (ctxt *Context) isDir(path string) bool {
+ if f := ctxt.IsDir; f != nil {
+ return f(path)
+ }
+ fi, err := os.Stat(path)
+ return err == nil && fi.IsDir()
+}
+
+// hasSubdir calls ctxt.HasSubdir (if not nil) or else uses
+// the local file system to answer the question.
+func (ctxt *Context) hasSubdir(root, dir string) (rel string, ok bool) {
+ if f := ctxt.HasSubdir; f != nil {
+ return f(root, dir)
+ }
+
+ // Try using paths we received.
+ if rel, ok = hasSubdir(root, dir); ok {
+ return
+ }
+
+ // Try expanding symlinks and comparing
+ // expanded against unexpanded and
+ // expanded against expanded.
+ rootSym, _ := filepath.EvalSymlinks(root)
+ dirSym, _ := filepath.EvalSymlinks(dir)
+
+ if rel, ok = hasSubdir(rootSym, dir); ok {
+ return
+ }
+ if rel, ok = hasSubdir(root, dirSym); ok {
+ return
+ }
+ return hasSubdir(rootSym, dirSym)
+}
+
+// hasSubdir reports if dir is within root by performing lexical analysis only.
+func hasSubdir(root, dir string) (rel string, ok bool) {
+ const sep = string(filepath.Separator)
+ root = filepath.Clean(root)
+ if !strings.HasSuffix(root, sep) {
+ root += sep
+ }
+ dir = filepath.Clean(dir)
+ if !strings.HasPrefix(dir, root) {
+ return "", false
+ }
+ return filepath.ToSlash(dir[len(root):]), true
+}
+
+// readDir calls ctxt.ReadDir (if not nil) or else os.ReadDir.
+func (ctxt *Context) readDir(path string) ([]fs.DirEntry, error) {
+ // TODO: add a fs.DirEntry version of Context.ReadDir
+ if f := ctxt.ReadDir; f != nil {
+ fis, err := f(path)
+ if err != nil {
+ return nil, err
+ }
+ des := make([]fs.DirEntry, len(fis))
+ for i, fi := range fis {
+ des[i] = fs.FileInfoToDirEntry(fi)
+ }
+ return des, nil
+ }
+ return os.ReadDir(path)
+}
+
+// openFile calls ctxt.OpenFile (if not nil) or else os.Open.
+func (ctxt *Context) openFile(path string) (io.ReadCloser, error) {
+ if fn := ctxt.OpenFile; fn != nil {
+ return fn(path)
+ }
+
+ f, err := os.Open(path)
+ if err != nil {
+ return nil, err // nil interface
+ }
+ return f, nil
+}
+
+// isFile determines whether path is a file by trying to open it.
+// It reuses openFile instead of adding another function to the
+// list in Context.
+func (ctxt *Context) isFile(path string) bool {
+ f, err := ctxt.openFile(path)
+ if err != nil {
+ return false
+ }
+ f.Close()
+ return true
+}
+
+// gopath returns the list of Go path directories.
+func (ctxt *Context) gopath() []string {
+ var all []string
+ for _, p := range ctxt.splitPathList(ctxt.GOPATH) {
+ if p == "" || p == ctxt.GOROOT {
+ // Empty paths are uninteresting.
+ // If the path is the GOROOT, ignore it.
+ // People sometimes set GOPATH=$GOROOT.
+ // Do not get confused by this common mistake.
+ continue
+ }
+ if strings.HasPrefix(p, "~") {
+ // Path segments starting with ~ on Unix are almost always
+ // users who have incorrectly quoted ~ while setting GOPATH,
+ // preventing it from expanding to $HOME.
+ // The situation is made more confusing by the fact that
+ // bash allows quoted ~ in $PATH (most shells do not).
+ // Do not get confused by this, and do not try to use the path.
+ // It does not exist, and printing errors about it confuses
+ // those users even more, because they think "sure ~ exists!".
+ // The go command diagnoses this situation and prints a
+ // useful error.
+ // On Windows, ~ is used in short names, such as c:\progra~1
+ // for c:\program files.
+ continue
+ }
+ all = append(all, p)
+ }
+ return all
+}
+
+// SrcDirs returns a list of package source root directories.
+// It draws from the current Go root and Go path but omits directories
+// that do not exist.
+func (ctxt *Context) SrcDirs() []string {
+ var all []string
+ if ctxt.GOROOT != "" && ctxt.Compiler != "gccgo" {
+ dir := ctxt.joinPath(ctxt.GOROOT, "src")
+ if ctxt.isDir(dir) {
+ all = append(all, dir)
+ }
+ }
+ for _, p := range ctxt.gopath() {
+ dir := ctxt.joinPath(p, "src")
+ if ctxt.isDir(dir) {
+ all = append(all, dir)
+ }
+ }
+ return all
+}
+
+// Default is the default Context for builds.
+// It uses the GOARCH, GOOS, GOROOT, and GOPATH environment variables
+// if set, or else the compiled code's GOARCH, GOOS, and GOROOT.
+var Default Context = defaultContext()
+
+func defaultGOPATH() string {
+ env := "HOME"
+ if runtime.GOOS == "windows" {
+ env = "USERPROFILE"
+ } else if runtime.GOOS == "plan9" {
+ env = "home"
+ }
+ if home := os.Getenv(env); home != "" {
+ def := filepath.Join(home, "go")
+ if filepath.Clean(def) == filepath.Clean(runtime.GOROOT()) {
+ // Don't set the default GOPATH to GOROOT,
+ // as that will trigger warnings from the go tool.
+ return ""
+ }
+ return def
+ }
+ return ""
+}
+
+var defaultToolTags, defaultReleaseTags []string
+
+func defaultContext() Context {
+ var c Context
+
+ c.GOARCH = buildcfg.GOARCH
+ c.GOOS = buildcfg.GOOS
+ if goroot := runtime.GOROOT(); goroot != "" {
+ c.GOROOT = filepath.Clean(goroot)
+ }
+ c.GOPATH = envOr("GOPATH", defaultGOPATH())
+ c.Compiler = runtime.Compiler
+
+ // For each experiment that has been enabled in the toolchain, define a
+ // build tag with the same name but prefixed by "goexperiment." which can be
+ // used for compiling alternative files for the experiment. This allows
+ // changes for the experiment, like extra struct fields in the runtime,
+ // without affecting the base non-experiment code at all.
+ for _, exp := range buildcfg.Experiment.Enabled() {
+ c.ToolTags = append(c.ToolTags, "goexperiment."+exp)
+ }
+ defaultToolTags = append([]string{}, c.ToolTags...) // our own private copy
+
+ // Each major Go release in the Go 1.x series adds a new
+ // "go1.x" release tag. That is, the go1.x tag is present in
+ // all releases >= Go 1.x. Code that requires Go 1.x or later
+ // should say "+build go1.x", and code that should only be
+ // built before Go 1.x (perhaps it is the stub to use in that
+ // case) should say "+build !go1.x".
+ // The last element in ReleaseTags is the current release.
+ for i := 1; i <= goversion.Version; i++ {
+ c.ReleaseTags = append(c.ReleaseTags, "go1."+strconv.Itoa(i))
+ }
+
+ defaultReleaseTags = append([]string{}, c.ReleaseTags...) // our own private copy
+
+ env := os.Getenv("CGO_ENABLED")
+ if env == "" {
+ env = defaultCGO_ENABLED
+ }
+ switch env {
+ case "1":
+ c.CgoEnabled = true
+ case "0":
+ c.CgoEnabled = false
+ default:
+ // cgo must be explicitly enabled for cross compilation builds
+ if runtime.GOARCH == c.GOARCH && runtime.GOOS == c.GOOS {
+ c.CgoEnabled = cgoEnabled[c.GOOS+"/"+c.GOARCH]
+ break
+ }
+ c.CgoEnabled = false
+ }
+
+ return c
+}
+
+func envOr(name, def string) string {
+ s := os.Getenv(name)
+ if s == "" {
+ return def
+ }
+ return s
+}
+
+// An ImportMode controls the behavior of the Import method.
+type ImportMode uint
+
+const (
+ // If FindOnly is set, Import stops after locating the directory
+ // that should contain the sources for a package. It does not
+ // read any files in the directory.
+ FindOnly ImportMode = 1 << iota
+
+ // If AllowBinary is set, Import can be satisfied by a compiled
+ // package object without corresponding sources.
+ //
+ // Deprecated:
+ // The supported way to create a compiled-only package is to
+ // write source code containing a //go:binary-only-package comment at
+ // the top of the file. Such a package will be recognized
+ // regardless of this flag setting (because it has source code)
+ // and will have BinaryOnly set to true in the returned Package.
+ AllowBinary
+
+ // If ImportComment is set, parse import comments on package statements.
+ // Import returns an error if it finds a comment it cannot understand
+ // or finds conflicting comments in multiple source files.
+ // See golang.org/s/go14customimport for more information.
+ ImportComment
+
+ // By default, Import searches vendor directories
+ // that apply in the given source directory before searching
+ // the GOROOT and GOPATH roots.
+ // If an Import finds and returns a package using a vendor
+ // directory, the resulting ImportPath is the complete path
+ // to the package, including the path elements leading up
+ // to and including "vendor".
+ // For example, if Import("y", "x/subdir", 0) finds
+ // "x/vendor/y", the returned package's ImportPath is "x/vendor/y",
+ // not plain "y".
+ // See golang.org/s/go15vendor for more information.
+ //
+ // Setting IgnoreVendor ignores vendor directories.
+ //
+ // In contrast to the package's ImportPath,
+ // the returned package's Imports, TestImports, and XTestImports
+ // are always the exact import paths from the source files:
+ // Import makes no attempt to resolve or check those paths.
+ IgnoreVendor
+)
+
+// A Package describes the Go package found in a directory.
+type Package struct {
+ Dir string // directory containing package sources
+ Name string // package name
+ ImportComment string // path in import comment on package statement
+ Doc string // documentation synopsis
+ ImportPath string // import path of package ("" if unknown)
+ Root string // root of Go tree where this package lives
+ SrcRoot string // package source root directory ("" if unknown)
+ PkgRoot string // package install root directory ("" if unknown)
+ PkgTargetRoot string // architecture dependent install root directory ("" if unknown)
+ BinDir string // command install directory ("" if unknown)
+ Goroot bool // package found in Go root
+ PkgObj string // installed .a file
+ AllTags []string // tags that can influence file selection in this directory
+ ConflictDir string // this directory shadows Dir in $GOPATH
+ BinaryOnly bool // cannot be rebuilt from source (has //go:binary-only-package comment)
+
+ // Source files
+ GoFiles []string // .go source files (excluding CgoFiles, TestGoFiles, XTestGoFiles)
+ CgoFiles []string // .go source files that import "C"
+ IgnoredGoFiles []string // .go source files ignored for this build (including ignored _test.go files)
+ InvalidGoFiles []string // .go source files with detected problems (parse error, wrong package name, and so on)
+ IgnoredOtherFiles []string // non-.go source files ignored for this build
+ CFiles []string // .c source files
+ CXXFiles []string // .cc, .cpp and .cxx source files
+ MFiles []string // .m (Objective-C) source files
+ HFiles []string // .h, .hh, .hpp and .hxx source files
+ FFiles []string // .f, .F, .for and .f90 Fortran source files
+ SFiles []string // .s source files
+ SwigFiles []string // .swig files
+ SwigCXXFiles []string // .swigcxx files
+ SysoFiles []string // .syso system object files to add to archive
+
+ // Cgo directives
+ CgoCFLAGS []string // Cgo CFLAGS directives
+ CgoCPPFLAGS []string // Cgo CPPFLAGS directives
+ CgoCXXFLAGS []string // Cgo CXXFLAGS directives
+ CgoFFLAGS []string // Cgo FFLAGS directives
+ CgoLDFLAGS []string // Cgo LDFLAGS directives
+ CgoPkgConfig []string // Cgo pkg-config directives
+
+ // Test information
+ TestGoFiles []string // _test.go files in package
+ XTestGoFiles []string // _test.go files outside package
+
+ // Dependency information
+ Imports []string // import paths from GoFiles, CgoFiles
+ ImportPos map[string][]token.Position // line information for Imports
+ TestImports []string // import paths from TestGoFiles
+ TestImportPos map[string][]token.Position // line information for TestImports
+ XTestImports []string // import paths from XTestGoFiles
+ XTestImportPos map[string][]token.Position // line information for XTestImports
+
+ // //go:embed patterns found in Go source files
+ // For example, if a source file says
+ // //go:embed a* b.c
+ // then the list will contain those two strings as separate entries.
+ // (See package embed for more details about //go:embed.)
+ EmbedPatterns []string // patterns from GoFiles, CgoFiles
+ EmbedPatternPos map[string][]token.Position // line information for EmbedPatterns
+ TestEmbedPatterns []string // patterns from TestGoFiles
+ TestEmbedPatternPos map[string][]token.Position // line information for TestEmbedPatterns
+ XTestEmbedPatterns []string // patterns from XTestGoFiles
+ XTestEmbedPatternPos map[string][]token.Position // line information for XTestEmbedPatternPos
+}
+
+// IsCommand reports whether the package is considered a
+// command to be installed (not just a library).
+// Packages named "main" are treated as commands.
+func (p *Package) IsCommand() bool {
+ return p.Name == "main"
+}
+
+// ImportDir is like Import but processes the Go package found in
+// the named directory.
+func (ctxt *Context) ImportDir(dir string, mode ImportMode) (*Package, error) {
+ return ctxt.Import(".", dir, mode)
+}
+
+// NoGoError is the error used by Import to describe a directory
+// containing no buildable Go source files. (It may still contain
+// test files, files hidden by build tags, and so on.)
+type NoGoError struct {
+ Dir string
+}
+
+func (e *NoGoError) Error() string {
+ return "no buildable Go source files in " + e.Dir
+}
+
+// MultiplePackageError describes a directory containing
+// multiple buildable Go source files for multiple packages.
+type MultiplePackageError struct {
+ Dir string // directory containing files
+ Packages []string // package names found
+ Files []string // corresponding files: Files[i] declares package Packages[i]
+}
+
+func (e *MultiplePackageError) Error() string {
+ // Error string limited to two entries for compatibility.
+ return fmt.Sprintf("found packages %s (%s) and %s (%s) in %s", e.Packages[0], e.Files[0], e.Packages[1], e.Files[1], e.Dir)
+}
+
+func nameExt(name string) string {
+ i := strings.LastIndex(name, ".")
+ if i < 0 {
+ return ""
+ }
+ return name[i:]
+}
+
+// Import returns details about the Go package named by the import path,
+// interpreting local import paths relative to the srcDir directory.
+// If the path is a local import path naming a package that can be imported
+// using a standard import path, the returned package will set p.ImportPath
+// to that path.
+//
+// In the directory containing the package, .go, .c, .h, and .s files are
+// considered part of the package except for:
+//
+// - .go files in package documentation
+// - files starting with _ or . (likely editor temporary files)
+// - files with build constraints not satisfied by the context
+//
+// If an error occurs, Import returns a non-nil error and a non-nil
+// *Package containing partial information.
+func (ctxt *Context) Import(path string, srcDir string, mode ImportMode) (*Package, error) {
+ p := &Package{
+ ImportPath: path,
+ }
+ if path == "" {
+ return p, fmt.Errorf("import %q: invalid import path", path)
+ }
+
+ var pkgtargetroot string
+ var pkga string
+ var pkgerr error
+ suffix := ""
+ if ctxt.InstallSuffix != "" {
+ suffix = "_" + ctxt.InstallSuffix
+ }
+ switch ctxt.Compiler {
+ case "gccgo":
+ pkgtargetroot = "pkg/gccgo_" + ctxt.GOOS + "_" + ctxt.GOARCH + suffix
+ case "gc":
+ pkgtargetroot = "pkg/" + ctxt.GOOS + "_" + ctxt.GOARCH + suffix
+ default:
+ // Save error for end of function.
+ pkgerr = fmt.Errorf("import %q: unknown compiler %q", path, ctxt.Compiler)
+ }
+ setPkga := func() {
+ switch ctxt.Compiler {
+ case "gccgo":
+ dir, elem := pathpkg.Split(p.ImportPath)
+ pkga = pkgtargetroot + "/" + dir + "lib" + elem + ".a"
+ case "gc":
+ pkga = pkgtargetroot + "/" + p.ImportPath + ".a"
+ }
+ }
+ setPkga()
+
+ binaryOnly := false
+ if IsLocalImport(path) {
+ pkga = "" // local imports have no installed path
+ if srcDir == "" {
+ return p, fmt.Errorf("import %q: import relative to unknown directory", path)
+ }
+ if !ctxt.isAbsPath(path) {
+ p.Dir = ctxt.joinPath(srcDir, path)
+ }
+ // p.Dir directory may or may not exist. Gather partial information first, check if it exists later.
+ // Determine canonical import path, if any.
+ // Exclude results where the import path would include /testdata/.
+ inTestdata := func(sub string) bool {
+ return strings.Contains(sub, "/testdata/") || strings.HasSuffix(sub, "/testdata") || strings.HasPrefix(sub, "testdata/") || sub == "testdata"
+ }
+ if ctxt.GOROOT != "" {
+ root := ctxt.joinPath(ctxt.GOROOT, "src")
+ if sub, ok := ctxt.hasSubdir(root, p.Dir); ok && !inTestdata(sub) {
+ p.Goroot = true
+ p.ImportPath = sub
+ p.Root = ctxt.GOROOT
+ setPkga() // p.ImportPath changed
+ goto Found
+ }
+ }
+ all := ctxt.gopath()
+ for i, root := range all {
+ rootsrc := ctxt.joinPath(root, "src")
+ if sub, ok := ctxt.hasSubdir(rootsrc, p.Dir); ok && !inTestdata(sub) {
+ // We found a potential import path for dir,
+ // but check that using it wouldn't find something
+ // else first.
+ if ctxt.GOROOT != "" && ctxt.Compiler != "gccgo" {
+ if dir := ctxt.joinPath(ctxt.GOROOT, "src", sub); ctxt.isDir(dir) {
+ p.ConflictDir = dir
+ goto Found
+ }
+ }
+ for _, earlyRoot := range all[:i] {
+ if dir := ctxt.joinPath(earlyRoot, "src", sub); ctxt.isDir(dir) {
+ p.ConflictDir = dir
+ goto Found
+ }
+ }
+
+ // sub would not name some other directory instead of this one.
+ // Record it.
+ p.ImportPath = sub
+ p.Root = root
+ setPkga() // p.ImportPath changed
+ goto Found
+ }
+ }
+ // It's okay that we didn't find a root containing dir.
+ // Keep going with the information we have.
+ } else {
+ if strings.HasPrefix(path, "/") {
+ return p, fmt.Errorf("import %q: cannot import absolute path", path)
+ }
+
+ if err := ctxt.importGo(p, path, srcDir, mode); err == nil {
+ goto Found
+ } else if err != errNoModules {
+ return p, err
+ }
+
+ gopath := ctxt.gopath() // needed twice below; avoid computing many times
+
+ // tried records the location of unsuccessful package lookups
+ var tried struct {
+ vendor []string
+ goroot string
+ gopath []string
+ }
+
+ // Vendor directories get first chance to satisfy import.
+ if mode&IgnoreVendor == 0 && srcDir != "" {
+ searchVendor := func(root string, isGoroot bool) bool {
+ sub, ok := ctxt.hasSubdir(root, srcDir)
+ if !ok || !strings.HasPrefix(sub, "src/") || strings.Contains(sub, "/testdata/") {
+ return false
+ }
+ for {
+ vendor := ctxt.joinPath(root, sub, "vendor")
+ if ctxt.isDir(vendor) {
+ dir := ctxt.joinPath(vendor, path)
+ if ctxt.isDir(dir) && hasGoFiles(ctxt, dir) {
+ p.Dir = dir
+ p.ImportPath = strings.TrimPrefix(pathpkg.Join(sub, "vendor", path), "src/")
+ p.Goroot = isGoroot
+ p.Root = root
+ setPkga() // p.ImportPath changed
+ return true
+ }
+ tried.vendor = append(tried.vendor, dir)
+ }
+ i := strings.LastIndex(sub, "/")
+ if i < 0 {
+ break
+ }
+ sub = sub[:i]
+ }
+ return false
+ }
+ if ctxt.Compiler != "gccgo" && ctxt.GOROOT != "" && searchVendor(ctxt.GOROOT, true) {
+ goto Found
+ }
+ for _, root := range gopath {
+ if searchVendor(root, false) {
+ goto Found
+ }
+ }
+ }
+
+ // Determine directory from import path.
+ if ctxt.GOROOT != "" {
+ // If the package path starts with "vendor/", only search GOROOT before
+ // GOPATH if the importer is also within GOROOT. That way, if the user has
+ // vendored in a package that is subsequently included in the standard
+ // distribution, they'll continue to pick up their own vendored copy.
+ gorootFirst := srcDir == "" || !strings.HasPrefix(path, "vendor/")
+ if !gorootFirst {
+ _, gorootFirst = ctxt.hasSubdir(ctxt.GOROOT, srcDir)
+ }
+ if gorootFirst {
+ dir := ctxt.joinPath(ctxt.GOROOT, "src", path)
+ if ctxt.Compiler != "gccgo" {
+ isDir := ctxt.isDir(dir)
+ binaryOnly = !isDir && mode&AllowBinary != 0 && pkga != "" && ctxt.isFile(ctxt.joinPath(ctxt.GOROOT, pkga))
+ if isDir || binaryOnly {
+ p.Dir = dir
+ p.Goroot = true
+ p.Root = ctxt.GOROOT
+ goto Found
+ }
+ }
+ tried.goroot = dir
+ }
+ if ctxt.Compiler == "gccgo" && goroot.IsStandardPackage(ctxt.GOROOT, ctxt.Compiler, path) {
+ p.Dir = ctxt.joinPath(ctxt.GOROOT, "src", path)
+ p.Goroot = true
+ p.Root = ctxt.GOROOT
+ goto Found
+ }
+ }
+ for _, root := range gopath {
+ dir := ctxt.joinPath(root, "src", path)
+ isDir := ctxt.isDir(dir)
+ binaryOnly = !isDir && mode&AllowBinary != 0 && pkga != "" && ctxt.isFile(ctxt.joinPath(root, pkga))
+ if isDir || binaryOnly {
+ p.Dir = dir
+ p.Root = root
+ goto Found
+ }
+ tried.gopath = append(tried.gopath, dir)
+ }
+
+ // If we tried GOPATH first due to a "vendor/" prefix, fall back to GOPATH.
+ // That way, the user can still get useful results from 'go list' for
+ // standard-vendored paths passed on the command line.
+ if ctxt.GOROOT != "" && tried.goroot == "" {
+ dir := ctxt.joinPath(ctxt.GOROOT, "src", path)
+ if ctxt.Compiler != "gccgo" {
+ isDir := ctxt.isDir(dir)
+ binaryOnly = !isDir && mode&AllowBinary != 0 && pkga != "" && ctxt.isFile(ctxt.joinPath(ctxt.GOROOT, pkga))
+ if isDir || binaryOnly {
+ p.Dir = dir
+ p.Goroot = true
+ p.Root = ctxt.GOROOT
+ goto Found
+ }
+ }
+ tried.goroot = dir
+ }
+
+ // package was not found
+ var paths []string
+ format := "\t%s (vendor tree)"
+ for _, dir := range tried.vendor {
+ paths = append(paths, fmt.Sprintf(format, dir))
+ format = "\t%s"
+ }
+ if tried.goroot != "" {
+ paths = append(paths, fmt.Sprintf("\t%s (from $GOROOT)", tried.goroot))
+ } else {
+ paths = append(paths, "\t($GOROOT not set)")
+ }
+ format = "\t%s (from $GOPATH)"
+ for _, dir := range tried.gopath {
+ paths = append(paths, fmt.Sprintf(format, dir))
+ format = "\t%s"
+ }
+ if len(tried.gopath) == 0 {
+ paths = append(paths, "\t($GOPATH not set. For more details see: 'go help gopath')")
+ }
+ return p, fmt.Errorf("cannot find package %q in any of:\n%s", path, strings.Join(paths, "\n"))
+ }
+
+Found:
+ if p.Root != "" {
+ p.SrcRoot = ctxt.joinPath(p.Root, "src")
+ p.PkgRoot = ctxt.joinPath(p.Root, "pkg")
+ p.BinDir = ctxt.joinPath(p.Root, "bin")
+ if pkga != "" {
+ p.PkgTargetRoot = ctxt.joinPath(p.Root, pkgtargetroot)
+ p.PkgObj = ctxt.joinPath(p.Root, pkga)
+ }
+ }
+
+ // If it's a local import path, by the time we get here, we still haven't checked
+ // that p.Dir directory exists. This is the right time to do that check.
+ // We can't do it earlier, because we want to gather partial information for the
+ // non-nil *Package returned when an error occurs.
+ // We need to do this before we return early on FindOnly flag.
+ if IsLocalImport(path) && !ctxt.isDir(p.Dir) {
+ if ctxt.Compiler == "gccgo" && p.Goroot {
+ // gccgo has no sources for GOROOT packages.
+ return p, nil
+ }
+
+ // package was not found
+ return p, fmt.Errorf("cannot find package %q in:\n\t%s", p.ImportPath, p.Dir)
+ }
+
+ if mode&FindOnly != 0 {
+ return p, pkgerr
+ }
+ if binaryOnly && (mode&AllowBinary) != 0 {
+ return p, pkgerr
+ }
+
+ if ctxt.Compiler == "gccgo" && p.Goroot {
+ // gccgo has no sources for GOROOT packages.
+ return p, nil
+ }
+
+ dirs, err := ctxt.readDir(p.Dir)
+ if err != nil {
+ return p, err
+ }
+
+ var badGoError error
+ badFiles := make(map[string]bool)
+ badFile := func(name string, err error) {
+ if badGoError == nil {
+ badGoError = err
+ }
+ if !badFiles[name] {
+ p.InvalidGoFiles = append(p.InvalidGoFiles, name)
+ badFiles[name] = true
+ }
+ }
+
+ var Sfiles []string // files with ".S"(capital S)/.sx(capital s equivalent for case insensitive filesystems)
+ var firstFile, firstCommentFile string
+ embedPos := make(map[string][]token.Position)
+ testEmbedPos := make(map[string][]token.Position)
+ xTestEmbedPos := make(map[string][]token.Position)
+ importPos := make(map[string][]token.Position)
+ testImportPos := make(map[string][]token.Position)
+ xTestImportPos := make(map[string][]token.Position)
+ allTags := make(map[string]bool)
+ fset := token.NewFileSet()
+ for _, d := range dirs {
+ if d.IsDir() {
+ continue
+ }
+ if d.Type() == fs.ModeSymlink {
+ if ctxt.isDir(ctxt.joinPath(p.Dir, d.Name())) {
+ // Symlinks to directories are not source files.
+ continue
+ }
+ }
+
+ name := d.Name()
+ ext := nameExt(name)
+
+ info, err := ctxt.matchFile(p.Dir, name, allTags, &p.BinaryOnly, fset)
+ if err != nil {
+ badFile(name, err)
+ continue
+ }
+ if info == nil {
+ if strings.HasPrefix(name, "_") || strings.HasPrefix(name, ".") {
+ // not due to build constraints - don't report
+ } else if ext == ".go" {
+ p.IgnoredGoFiles = append(p.IgnoredGoFiles, name)
+ } else if fileListForExt(p, ext) != nil {
+ p.IgnoredOtherFiles = append(p.IgnoredOtherFiles, name)
+ }
+ continue
+ }
+ data, filename := info.header, info.name
+
+ // Going to save the file. For non-Go files, can stop here.
+ switch ext {
+ case ".go":
+ // keep going
+ case ".S", ".sx":
+ // special case for cgo, handled at end
+ Sfiles = append(Sfiles, name)
+ continue
+ default:
+ if list := fileListForExt(p, ext); list != nil {
+ *list = append(*list, name)
+ }
+ continue
+ }
+
+ if info.parseErr != nil {
+ badFile(name, info.parseErr)
+ // Fall through: we might still have a partial AST in info.parsed,
+ // and we want to list files with parse errors anyway.
+ }
+
+ var pkg string
+ if info.parsed != nil {
+ pkg = info.parsed.Name.Name
+ if pkg == "documentation" {
+ p.IgnoredGoFiles = append(p.IgnoredGoFiles, name)
+ continue
+ }
+ }
+
+ isTest := strings.HasSuffix(name, "_test.go")
+ isXTest := false
+ if isTest && strings.HasSuffix(pkg, "_test") && p.Name != pkg {
+ isXTest = true
+ pkg = pkg[:len(pkg)-len("_test")]
+ }
+
+ if p.Name == "" {
+ p.Name = pkg
+ firstFile = name
+ } else if pkg != p.Name {
+ // TODO(#45999): The choice of p.Name is arbitrary based on file iteration
+ // order. Instead of resolving p.Name arbitrarily, we should clear out the
+ // existing name and mark the existing files as also invalid.
+ badFile(name, &MultiplePackageError{
+ Dir: p.Dir,
+ Packages: []string{p.Name, pkg},
+ Files: []string{firstFile, name},
+ })
+ }
+ // Grab the first package comment as docs, provided it is not from a test file.
+ if info.parsed != nil && info.parsed.Doc != nil && p.Doc == "" && !isTest && !isXTest {
+ p.Doc = doc.Synopsis(info.parsed.Doc.Text())
+ }
+
+ if mode&ImportComment != 0 {
+ qcom, line := findImportComment(data)
+ if line != 0 {
+ com, err := strconv.Unquote(qcom)
+ if err != nil {
+ badFile(name, fmt.Errorf("%s:%d: cannot parse import comment", filename, line))
+ } else if p.ImportComment == "" {
+ p.ImportComment = com
+ firstCommentFile = name
+ } else if p.ImportComment != com {
+ badFile(name, fmt.Errorf("found import comments %q (%s) and %q (%s) in %s", p.ImportComment, firstCommentFile, com, name, p.Dir))
+ }
+ }
+ }
+
+ // Record imports and information about cgo.
+ isCgo := false
+ for _, imp := range info.imports {
+ if imp.path == "C" {
+ if isTest {
+ badFile(name, fmt.Errorf("use of cgo in test %s not supported", filename))
+ continue
+ }
+ isCgo = true
+ if imp.doc != nil {
+ if err := ctxt.saveCgo(filename, p, imp.doc); err != nil {
+ badFile(name, err)
+ }
+ }
+ }
+ }
+
+ var fileList *[]string
+ var importMap, embedMap map[string][]token.Position
+ switch {
+ case isCgo:
+ allTags["cgo"] = true
+ if ctxt.CgoEnabled {
+ fileList = &p.CgoFiles
+ importMap = importPos
+ embedMap = embedPos
+ } else {
+ // Ignore imports and embeds from cgo files if cgo is disabled.
+ fileList = &p.IgnoredGoFiles
+ }
+ case isXTest:
+ fileList = &p.XTestGoFiles
+ importMap = xTestImportPos
+ embedMap = xTestEmbedPos
+ case isTest:
+ fileList = &p.TestGoFiles
+ importMap = testImportPos
+ embedMap = testEmbedPos
+ default:
+ fileList = &p.GoFiles
+ importMap = importPos
+ embedMap = embedPos
+ }
+ *fileList = append(*fileList, name)
+ if importMap != nil {
+ for _, imp := range info.imports {
+ importMap[imp.path] = append(importMap[imp.path], fset.Position(imp.pos))
+ }
+ }
+ if embedMap != nil {
+ for _, emb := range info.embeds {
+ embedMap[emb.pattern] = append(embedMap[emb.pattern], emb.pos)
+ }
+ }
+ }
+
+ for tag := range allTags {
+ p.AllTags = append(p.AllTags, tag)
+ }
+ sort.Strings(p.AllTags)
+
+ p.EmbedPatterns, p.EmbedPatternPos = cleanDecls(embedPos)
+ p.TestEmbedPatterns, p.TestEmbedPatternPos = cleanDecls(testEmbedPos)
+ p.XTestEmbedPatterns, p.XTestEmbedPatternPos = cleanDecls(xTestEmbedPos)
+
+ p.Imports, p.ImportPos = cleanDecls(importPos)
+ p.TestImports, p.TestImportPos = cleanDecls(testImportPos)
+ p.XTestImports, p.XTestImportPos = cleanDecls(xTestImportPos)
+
+ // add the .S/.sx files only if we are using cgo
+ // (which means gcc will compile them).
+ // The standard assemblers expect .s files.
+ if len(p.CgoFiles) > 0 {
+ p.SFiles = append(p.SFiles, Sfiles...)
+ sort.Strings(p.SFiles)
+ } else {
+ p.IgnoredOtherFiles = append(p.IgnoredOtherFiles, Sfiles...)
+ sort.Strings(p.IgnoredOtherFiles)
+ }
+
+ if badGoError != nil {
+ return p, badGoError
+ }
+ if len(p.GoFiles)+len(p.CgoFiles)+len(p.TestGoFiles)+len(p.XTestGoFiles) == 0 {
+ return p, &NoGoError{p.Dir}
+ }
+ return p, pkgerr
+}
+
+func fileListForExt(p *Package, ext string) *[]string {
+ switch ext {
+ case ".c":
+ return &p.CFiles
+ case ".cc", ".cpp", ".cxx":
+ return &p.CXXFiles
+ case ".m":
+ return &p.MFiles
+ case ".h", ".hh", ".hpp", ".hxx":
+ return &p.HFiles
+ case ".f", ".F", ".for", ".f90":
+ return &p.FFiles
+ case ".s", ".S", ".sx":
+ return &p.SFiles
+ case ".swig":
+ return &p.SwigFiles
+ case ".swigcxx":
+ return &p.SwigCXXFiles
+ case ".syso":
+ return &p.SysoFiles
+ }
+ return nil
+}
+
+func uniq(list []string) []string {
+ if list == nil {
+ return nil
+ }
+ out := make([]string, len(list))
+ copy(out, list)
+ sort.Strings(out)
+ uniq := out[:0]
+ for _, x := range out {
+ if len(uniq) == 0 || uniq[len(uniq)-1] != x {
+ uniq = append(uniq, x)
+ }
+ }
+ return uniq
+}
+
+var errNoModules = errors.New("not using modules")
+
+// importGo checks whether it can use the go command to find the directory for path.
+// If using the go command is not appropriate, importGo returns errNoModules.
+// Otherwise, importGo tries using the go command and reports whether that succeeded.
+// Using the go command lets build.Import and build.Context.Import find code
+// in Go modules. In the long term we want tools to use go/packages (currently golang.org/x/tools/go/packages),
+// which will also use the go command.
+// Invoking the go command here is not very efficient in that it computes information
+// about the requested package and all dependencies and then only reports about the requested package.
+// Then we reinvoke it for every dependency. But this is still better than not working at all.
+// See golang.org/issue/26504.
+func (ctxt *Context) importGo(p *Package, path, srcDir string, mode ImportMode) error {
+ // To invoke the go command,
+ // we must not being doing special things like AllowBinary or IgnoreVendor,
+ // and all the file system callbacks must be nil (we're meant to use the local file system).
+ if mode&AllowBinary != 0 || mode&IgnoreVendor != 0 ||
+ ctxt.JoinPath != nil || ctxt.SplitPathList != nil || ctxt.IsAbsPath != nil || ctxt.IsDir != nil || ctxt.HasSubdir != nil || ctxt.ReadDir != nil || ctxt.OpenFile != nil || !equal(ctxt.ToolTags, defaultToolTags) || !equal(ctxt.ReleaseTags, defaultReleaseTags) {
+ return errNoModules
+ }
+
+ // If ctxt.GOROOT is not set, we don't know which go command to invoke,
+ // and even if we did we might return packages in GOROOT that we wouldn't otherwise find
+ // (because we don't know to search in 'go env GOROOT' otherwise).
+ if ctxt.GOROOT == "" {
+ return errNoModules
+ }
+
+ // Predict whether module aware mode is enabled by checking the value of
+ // GO111MODULE and looking for a go.mod file in the source directory or
+ // one of its parents. Running 'go env GOMOD' in the source directory would
+ // give a canonical answer, but we'd prefer not to execute another command.
+ go111Module := os.Getenv("GO111MODULE")
+ switch go111Module {
+ case "off":
+ return errNoModules
+ default: // "", "on", "auto", anything else
+ // Maybe use modules.
+ }
+
+ if srcDir != "" {
+ var absSrcDir string
+ if filepath.IsAbs(srcDir) {
+ absSrcDir = srcDir
+ } else if ctxt.Dir != "" {
+ return fmt.Errorf("go/build: Dir is non-empty, so relative srcDir is not allowed: %v", srcDir)
+ } else {
+ // Find the absolute source directory. hasSubdir does not handle
+ // relative paths (and can't because the callbacks don't support this).
+ var err error
+ absSrcDir, err = filepath.Abs(srcDir)
+ if err != nil {
+ return errNoModules
+ }
+ }
+
+ // If the source directory is in GOROOT, then the in-process code works fine
+ // and we should keep using it. Moreover, the 'go list' approach below doesn't
+ // take standard-library vendoring into account and will fail.
+ if _, ok := ctxt.hasSubdir(filepath.Join(ctxt.GOROOT, "src"), absSrcDir); ok {
+ return errNoModules
+ }
+ }
+
+ // For efficiency, if path is a standard library package, let the usual lookup code handle it.
+ if dir := ctxt.joinPath(ctxt.GOROOT, "src", path); ctxt.isDir(dir) {
+ return errNoModules
+ }
+
+ // If GO111MODULE=auto, look to see if there is a go.mod.
+ // Since go1.13, it doesn't matter if we're inside GOPATH.
+ if go111Module == "auto" {
+ var (
+ parent string
+ err error
+ )
+ if ctxt.Dir == "" {
+ parent, err = os.Getwd()
+ if err != nil {
+ // A nonexistent working directory can't be in a module.
+ return errNoModules
+ }
+ } else {
+ parent, err = filepath.Abs(ctxt.Dir)
+ if err != nil {
+ // If the caller passed a bogus Dir explicitly, that's materially
+ // different from not having modules enabled.
+ return err
+ }
+ }
+ for {
+ if f, err := ctxt.openFile(ctxt.joinPath(parent, "go.mod")); err == nil {
+ buf := make([]byte, 100)
+ _, err := f.Read(buf)
+ f.Close()
+ if err == nil || err == io.EOF {
+ // go.mod exists and is readable (is a file, not a directory).
+ break
+ }
+ }
+ d := filepath.Dir(parent)
+ if len(d) >= len(parent) {
+ return errNoModules // reached top of file system, no go.mod
+ }
+ parent = d
+ }
+ }
+
+ goCmd := filepath.Join(ctxt.GOROOT, "bin", "go")
+ cmd := exec.Command(goCmd, "list", "-e", "-compiler="+ctxt.Compiler, "-tags="+strings.Join(ctxt.BuildTags, ","), "-installsuffix="+ctxt.InstallSuffix, "-f={{.Dir}}\n{{.ImportPath}}\n{{.Root}}\n{{.Goroot}}\n{{if .Error}}{{.Error}}{{end}}\n", "--", path)
+
+ if ctxt.Dir != "" {
+ cmd.Dir = ctxt.Dir
+ }
+
+ var stdout, stderr strings.Builder
+ cmd.Stdout = &stdout
+ cmd.Stderr = &stderr
+
+ cgo := "0"
+ if ctxt.CgoEnabled {
+ cgo = "1"
+ }
+ cmd.Env = append(cmd.Environ(),
+ "GOOS="+ctxt.GOOS,
+ "GOARCH="+ctxt.GOARCH,
+ "GOROOT="+ctxt.GOROOT,
+ "GOPATH="+ctxt.GOPATH,
+ "CGO_ENABLED="+cgo,
+ )
+
+ if err := cmd.Run(); err != nil {
+ return fmt.Errorf("go/build: go list %s: %v\n%s\n", path, err, stderr.String())
+ }
+
+ f := strings.SplitN(stdout.String(), "\n", 5)
+ if len(f) != 5 {
+ return fmt.Errorf("go/build: importGo %s: unexpected output:\n%s\n", path, stdout.String())
+ }
+ dir := f[0]
+ errStr := strings.TrimSpace(f[4])
+ if errStr != "" && dir == "" {
+ // If 'go list' could not locate the package (dir is empty),
+ // return the same error that 'go list' reported.
+ return errors.New(errStr)
+ }
+
+ // If 'go list' did locate the package, ignore the error.
+ // It was probably related to loading source files, and we'll
+ // encounter it ourselves shortly if the FindOnly flag isn't set.
+ p.Dir = dir
+ p.ImportPath = f[1]
+ p.Root = f[2]
+ p.Goroot = f[3] == "true"
+ return nil
+}
+
+func equal(x, y []string) bool {
+ if len(x) != len(y) {
+ return false
+ }
+ for i, xi := range x {
+ if xi != y[i] {
+ return false
+ }
+ }
+ return true
+}
+
+// hasGoFiles reports whether dir contains any files with names ending in .go.
+// For a vendor check we must exclude directories that contain no .go files.
+// Otherwise it is not possible to vendor just a/b/c and still import the
+// non-vendored a/b. See golang.org/issue/13832.
+func hasGoFiles(ctxt *Context, dir string) bool {
+ ents, _ := ctxt.readDir(dir)
+ for _, ent := range ents {
+ if !ent.IsDir() && strings.HasSuffix(ent.Name(), ".go") {
+ return true
+ }
+ }
+ return false
+}
+
+func findImportComment(data []byte) (s string, line int) {
+ // expect keyword package
+ word, data := parseWord(data)
+ if string(word) != "package" {
+ return "", 0
+ }
+
+ // expect package name
+ _, data = parseWord(data)
+
+ // now ready for import comment, a // or /* */ comment
+ // beginning and ending on the current line.
+ for len(data) > 0 && (data[0] == ' ' || data[0] == '\t' || data[0] == '\r') {
+ data = data[1:]
+ }
+
+ var comment []byte
+ switch {
+ case bytes.HasPrefix(data, slashSlash):
+ comment, _, _ = bytes.Cut(data[2:], newline)
+ case bytes.HasPrefix(data, slashStar):
+ var ok bool
+ comment, _, ok = bytes.Cut(data[2:], starSlash)
+ if !ok {
+ // malformed comment
+ return "", 0
+ }
+ if bytes.Contains(comment, newline) {
+ return "", 0
+ }
+ }
+ comment = bytes.TrimSpace(comment)
+
+ // split comment into `import`, `"pkg"`
+ word, arg := parseWord(comment)
+ if string(word) != "import" {
+ return "", 0
+ }
+
+ line = 1 + bytes.Count(data[:cap(data)-cap(arg)], newline)
+ return strings.TrimSpace(string(arg)), line
+}
+
+var (
+ slashSlash = []byte("//")
+ slashStar = []byte("/*")
+ starSlash = []byte("*/")
+ newline = []byte("\n")
+)
+
+// skipSpaceOrComment returns data with any leading spaces or comments removed.
+func skipSpaceOrComment(data []byte) []byte {
+ for len(data) > 0 {
+ switch data[0] {
+ case ' ', '\t', '\r', '\n':
+ data = data[1:]
+ continue
+ case '/':
+ if bytes.HasPrefix(data, slashSlash) {
+ i := bytes.Index(data, newline)
+ if i < 0 {
+ return nil
+ }
+ data = data[i+1:]
+ continue
+ }
+ if bytes.HasPrefix(data, slashStar) {
+ data = data[2:]
+ i := bytes.Index(data, starSlash)
+ if i < 0 {
+ return nil
+ }
+ data = data[i+2:]
+ continue
+ }
+ }
+ break
+ }
+ return data
+}
+
+// parseWord skips any leading spaces or comments in data
+// and then parses the beginning of data as an identifier or keyword,
+// returning that word and what remains after the word.
+func parseWord(data []byte) (word, rest []byte) {
+ data = skipSpaceOrComment(data)
+
+ // Parse past leading word characters.
+ rest = data
+ for {
+ r, size := utf8.DecodeRune(rest)
+ if unicode.IsLetter(r) || '0' <= r && r <= '9' || r == '_' {
+ rest = rest[size:]
+ continue
+ }
+ break
+ }
+
+ word = data[:len(data)-len(rest)]
+ if len(word) == 0 {
+ return nil, nil
+ }
+
+ return word, rest
+}
+
+// MatchFile reports whether the file with the given name in the given directory
+// matches the context and would be included in a Package created by ImportDir
+// of that directory.
+//
+// MatchFile considers the name of the file and may use ctxt.OpenFile to
+// read some or all of the file's content.
+func (ctxt *Context) MatchFile(dir, name string) (match bool, err error) {
+ info, err := ctxt.matchFile(dir, name, nil, nil, nil)
+ return info != nil, err
+}
+
+var dummyPkg Package
+
+// fileInfo records information learned about a file included in a build.
+type fileInfo struct {
+ name string // full name including dir
+ header []byte
+ fset *token.FileSet
+ parsed *ast.File
+ parseErr error
+ imports []fileImport
+ embeds []fileEmbed
+}
+
+type fileImport struct {
+ path string
+ pos token.Pos
+ doc *ast.CommentGroup
+}
+
+type fileEmbed struct {
+ pattern string
+ pos token.Position
+}
+
+// matchFile determines whether the file with the given name in the given directory
+// should be included in the package being constructed.
+// If the file should be included, matchFile returns a non-nil *fileInfo (and a nil error).
+// Non-nil errors are reserved for unexpected problems.
+//
+// If name denotes a Go program, matchFile reads until the end of the
+// imports and returns that section of the file in the fileInfo's header field,
+// even though it only considers text until the first non-comment
+// for +build lines.
+//
+// If allTags is non-nil, matchFile records any encountered build tag
+// by setting allTags[tag] = true.
+func (ctxt *Context) matchFile(dir, name string, allTags map[string]bool, binaryOnly *bool, fset *token.FileSet) (*fileInfo, error) {
+ if strings.HasPrefix(name, "_") ||
+ strings.HasPrefix(name, ".") {
+ return nil, nil
+ }
+
+ i := strings.LastIndex(name, ".")
+ if i < 0 {
+ i = len(name)
+ }
+ ext := name[i:]
+
+ if !ctxt.goodOSArchFile(name, allTags) && !ctxt.UseAllFiles {
+ return nil, nil
+ }
+
+ if ext != ".go" && fileListForExt(&dummyPkg, ext) == nil {
+ // skip
+ return nil, nil
+ }
+
+ info := &fileInfo{name: ctxt.joinPath(dir, name), fset: fset}
+ if ext == ".syso" {
+ // binary, no reading
+ return info, nil
+ }
+
+ f, err := ctxt.openFile(info.name)
+ if err != nil {
+ return nil, err
+ }
+
+ if strings.HasSuffix(name, ".go") {
+ err = readGoInfo(f, info)
+ if strings.HasSuffix(name, "_test.go") {
+ binaryOnly = nil // ignore //go:binary-only-package comments in _test.go files
+ }
+ } else {
+ binaryOnly = nil // ignore //go:binary-only-package comments in non-Go sources
+ info.header, err = readComments(f)
+ }
+ f.Close()
+ if err != nil {
+ return nil, fmt.Errorf("read %s: %v", info.name, err)
+ }
+
+ // Look for +build comments to accept or reject the file.
+ ok, sawBinaryOnly, err := ctxt.shouldBuild(info.header, allTags)
+ if err != nil {
+ return nil, fmt.Errorf("%s: %v", name, err)
+ }
+ if !ok && !ctxt.UseAllFiles {
+ return nil, nil
+ }
+
+ if binaryOnly != nil && sawBinaryOnly {
+ *binaryOnly = true
+ }
+
+ return info, nil
+}
+
+func cleanDecls(m map[string][]token.Position) ([]string, map[string][]token.Position) {
+ all := make([]string, 0, len(m))
+ for path := range m {
+ all = append(all, path)
+ }
+ sort.Strings(all)
+ return all, m
+}
+
+// Import is shorthand for Default.Import.
+func Import(path, srcDir string, mode ImportMode) (*Package, error) {
+ return Default.Import(path, srcDir, mode)
+}
+
+// ImportDir is shorthand for Default.ImportDir.
+func ImportDir(dir string, mode ImportMode) (*Package, error) {
+ return Default.ImportDir(dir, mode)
+}
+
+var (
+ bSlashSlash = []byte(slashSlash)
+ bStarSlash = []byte(starSlash)
+ bSlashStar = []byte(slashStar)
+ bPlusBuild = []byte("+build")
+
+ goBuildComment = []byte("//go:build")
+
+ errGoBuildWithoutBuild = errors.New("//go:build comment without // +build comment")
+ errMultipleGoBuild = errors.New("multiple //go:build comments")
+)
+
+func isGoBuildComment(line []byte) bool {
+ if !bytes.HasPrefix(line, goBuildComment) {
+ return false
+ }
+ line = bytes.TrimSpace(line)
+ rest := line[len(goBuildComment):]
+ return len(rest) == 0 || len(bytes.TrimSpace(rest)) < len(rest)
+}
+
+// Special comment denoting a binary-only package.
+// See https://golang.org/design/2775-binary-only-packages
+// for more about the design of binary-only packages.
+var binaryOnlyComment = []byte("//go:binary-only-package")
+
+// shouldBuild reports whether it is okay to use this file,
+// The rule is that in the file's leading run of // comments
+// and blank lines, which must be followed by a blank line
+// (to avoid including a Go package clause doc comment),
+// lines beginning with '// +build' are taken as build directives.
+//
+// The file is accepted only if each such line lists something
+// matching the file. For example:
+//
+// // +build windows linux
+//
+// marks the file as applicable only on Windows and Linux.
+//
+// For each build tag it consults, shouldBuild sets allTags[tag] = true.
+//
+// shouldBuild reports whether the file should be built
+// and whether a //go:binary-only-package comment was found.
+func (ctxt *Context) shouldBuild(content []byte, allTags map[string]bool) (shouldBuild, binaryOnly bool, err error) {
+ // Identify leading run of // comments and blank lines,
+ // which must be followed by a blank line.
+ // Also identify any //go:build comments.
+ content, goBuild, sawBinaryOnly, err := parseFileHeader(content)
+ if err != nil {
+ return false, false, err
+ }
+
+ // If //go:build line is present, it controls.
+ // Otherwise fall back to +build processing.
+ switch {
+ case goBuild != nil:
+ x, err := constraint.Parse(string(goBuild))
+ if err != nil {
+ return false, false, fmt.Errorf("parsing //go:build line: %v", err)
+ }
+ shouldBuild = ctxt.eval(x, allTags)
+
+ default:
+ shouldBuild = true
+ p := content
+ for len(p) > 0 {
+ line := p
+ if i := bytes.IndexByte(line, '\n'); i >= 0 {
+ line, p = line[:i], p[i+1:]
+ } else {
+ p = p[len(p):]
+ }
+ line = bytes.TrimSpace(line)
+ if !bytes.HasPrefix(line, bSlashSlash) || !bytes.Contains(line, bPlusBuild) {
+ continue
+ }
+ text := string(line)
+ if !constraint.IsPlusBuild(text) {
+ continue
+ }
+ if x, err := constraint.Parse(text); err == nil {
+ if !ctxt.eval(x, allTags) {
+ shouldBuild = false
+ }
+ }
+ }
+ }
+
+ return shouldBuild, sawBinaryOnly, nil
+}
+
+func parseFileHeader(content []byte) (trimmed, goBuild []byte, sawBinaryOnly bool, err error) {
+ end := 0
+ p := content
+ ended := false // found non-blank, non-// line, so stopped accepting // +build lines
+ inSlashStar := false // in /* */ comment
+
+Lines:
+ for len(p) > 0 {
+ line := p
+ if i := bytes.IndexByte(line, '\n'); i >= 0 {
+ line, p = line[:i], p[i+1:]
+ } else {
+ p = p[len(p):]
+ }
+ line = bytes.TrimSpace(line)
+ if len(line) == 0 && !ended { // Blank line
+ // Remember position of most recent blank line.
+ // When we find the first non-blank, non-// line,
+ // this "end" position marks the latest file position
+ // where a // +build line can appear.
+ // (It must appear _before_ a blank line before the non-blank, non-// line.
+ // Yes, that's confusing, which is part of why we moved to //go:build lines.)
+ // Note that ended==false here means that inSlashStar==false,
+ // since seeing a /* would have set ended==true.
+ end = len(content) - len(p)
+ continue Lines
+ }
+ if !bytes.HasPrefix(line, slashSlash) { // Not comment line
+ ended = true
+ }
+
+ if !inSlashStar && isGoBuildComment(line) {
+ if goBuild != nil {
+ return nil, nil, false, errMultipleGoBuild
+ }
+ goBuild = line
+ }
+ if !inSlashStar && bytes.Equal(line, binaryOnlyComment) {
+ sawBinaryOnly = true
+ }
+
+ Comments:
+ for len(line) > 0 {
+ if inSlashStar {
+ if i := bytes.Index(line, starSlash); i >= 0 {
+ inSlashStar = false
+ line = bytes.TrimSpace(line[i+len(starSlash):])
+ continue Comments
+ }
+ continue Lines
+ }
+ if bytes.HasPrefix(line, bSlashSlash) {
+ continue Lines
+ }
+ if bytes.HasPrefix(line, bSlashStar) {
+ inSlashStar = true
+ line = bytes.TrimSpace(line[len(bSlashStar):])
+ continue Comments
+ }
+ // Found non-comment text.
+ break Lines
+ }
+ }
+
+ return content[:end], goBuild, sawBinaryOnly, nil
+}
+
+// saveCgo saves the information from the #cgo lines in the import "C" comment.
+// These lines set CFLAGS, CPPFLAGS, CXXFLAGS and LDFLAGS and pkg-config directives
+// that affect the way cgo's C code is built.
+func (ctxt *Context) saveCgo(filename string, di *Package, cg *ast.CommentGroup) error {
+ text := cg.Text()
+ for _, line := range strings.Split(text, "\n") {
+ orig := line
+
+ // Line is
+ // #cgo [GOOS/GOARCH...] LDFLAGS: stuff
+ //
+ line = strings.TrimSpace(line)
+ if len(line) < 5 || line[:4] != "#cgo" || (line[4] != ' ' && line[4] != '\t') {
+ continue
+ }
+
+ // Split at colon.
+ line, argstr, ok := strings.Cut(strings.TrimSpace(line[4:]), ":")
+ if !ok {
+ return fmt.Errorf("%s: invalid #cgo line: %s", filename, orig)
+ }
+
+ // Parse GOOS/GOARCH stuff.
+ f := strings.Fields(line)
+ if len(f) < 1 {
+ return fmt.Errorf("%s: invalid #cgo line: %s", filename, orig)
+ }
+
+ cond, verb := f[:len(f)-1], f[len(f)-1]
+ if len(cond) > 0 {
+ ok := false
+ for _, c := range cond {
+ if ctxt.matchAuto(c, nil) {
+ ok = true
+ break
+ }
+ }
+ if !ok {
+ continue
+ }
+ }
+
+ args, err := splitQuoted(argstr)
+ if err != nil {
+ return fmt.Errorf("%s: invalid #cgo line: %s", filename, orig)
+ }
+ for i, arg := range args {
+ if arg, ok = expandSrcDir(arg, di.Dir); !ok {
+ return fmt.Errorf("%s: malformed #cgo argument: %s", filename, arg)
+ }
+ args[i] = arg
+ }
+
+ switch verb {
+ case "CFLAGS", "CPPFLAGS", "CXXFLAGS", "FFLAGS", "LDFLAGS":
+ // Change relative paths to absolute.
+ ctxt.makePathsAbsolute(args, di.Dir)
+ }
+
+ switch verb {
+ case "CFLAGS":
+ di.CgoCFLAGS = append(di.CgoCFLAGS, args...)
+ case "CPPFLAGS":
+ di.CgoCPPFLAGS = append(di.CgoCPPFLAGS, args...)
+ case "CXXFLAGS":
+ di.CgoCXXFLAGS = append(di.CgoCXXFLAGS, args...)
+ case "FFLAGS":
+ di.CgoFFLAGS = append(di.CgoFFLAGS, args...)
+ case "LDFLAGS":
+ di.CgoLDFLAGS = append(di.CgoLDFLAGS, args...)
+ case "pkg-config":
+ di.CgoPkgConfig = append(di.CgoPkgConfig, args...)
+ default:
+ return fmt.Errorf("%s: invalid #cgo verb: %s", filename, orig)
+ }
+ }
+ return nil
+}
+
+// expandSrcDir expands any occurrence of ${SRCDIR}, making sure
+// the result is safe for the shell.
+func expandSrcDir(str string, srcdir string) (string, bool) {
+ // "\" delimited paths cause safeCgoName to fail
+ // so convert native paths with a different delimiter
+ // to "/" before starting (eg: on windows).
+ srcdir = filepath.ToSlash(srcdir)
+
+ chunks := strings.Split(str, "${SRCDIR}")
+ if len(chunks) < 2 {
+ return str, safeCgoName(str)
+ }
+ ok := true
+ for _, chunk := range chunks {
+ ok = ok && (chunk == "" || safeCgoName(chunk))
+ }
+ ok = ok && (srcdir == "" || safeCgoName(srcdir))
+ res := strings.Join(chunks, srcdir)
+ return res, ok && res != ""
+}
+
+// makePathsAbsolute looks for compiler options that take paths and
+// makes them absolute. We do this because through the 1.8 release we
+// ran the compiler in the package directory, so any relative -I or -L
+// options would be relative to that directory. In 1.9 we changed to
+// running the compiler in the build directory, to get consistent
+// build results (issue #19964). To keep builds working, we change any
+// relative -I or -L options to be absolute.
+//
+// Using filepath.IsAbs and filepath.Join here means the results will be
+// different on different systems, but that's OK: -I and -L options are
+// inherently system-dependent.
+func (ctxt *Context) makePathsAbsolute(args []string, srcDir string) {
+ nextPath := false
+ for i, arg := range args {
+ if nextPath {
+ if !filepath.IsAbs(arg) {
+ args[i] = filepath.Join(srcDir, arg)
+ }
+ nextPath = false
+ } else if strings.HasPrefix(arg, "-I") || strings.HasPrefix(arg, "-L") {
+ if len(arg) == 2 {
+ nextPath = true
+ } else {
+ if !filepath.IsAbs(arg[2:]) {
+ args[i] = arg[:2] + filepath.Join(srcDir, arg[2:])
+ }
+ }
+ }
+ }
+}
+
+// NOTE: $ is not safe for the shell, but it is allowed here because of linker options like -Wl,$ORIGIN.
+// We never pass these arguments to a shell (just to programs we construct argv for), so this should be okay.
+// See golang.org/issue/6038.
+// The @ is for OS X. See golang.org/issue/13720.
+// The % is for Jenkins. See golang.org/issue/16959.
+// The ! is because module paths may use them. See golang.org/issue/26716.
+// The ~ and ^ are for sr.ht. See golang.org/issue/32260.
+const safeString = "+-.,/0123456789=ABCDEFGHIJKLMNOPQRSTUVWXYZ_abcdefghijklmnopqrstuvwxyz:$@%! ~^"
+
+func safeCgoName(s string) bool {
+ if s == "" {
+ return false
+ }
+ for i := 0; i < len(s); i++ {
+ if c := s[i]; c < utf8.RuneSelf && strings.IndexByte(safeString, c) < 0 {
+ return false
+ }
+ }
+ return true
+}
+
+// splitQuoted splits the string s around each instance of one or more consecutive
+// white space characters while taking into account quotes and escaping, and
+// returns an array of substrings of s or an empty list if s contains only white space.
+// Single quotes and double quotes are recognized to prevent splitting within the
+// quoted region, and are removed from the resulting substrings. If a quote in s
+// isn't closed err will be set and r will have the unclosed argument as the
+// last element. The backslash is used for escaping.
+//
+// For example, the following string:
+//
+// a b:"c d" 'e''f' "g\""
+//
+// Would be parsed as:
+//
+// []string{"a", "b:c d", "ef", `g"`}
+func splitQuoted(s string) (r []string, err error) {
+ var args []string
+ arg := make([]rune, len(s))
+ escaped := false
+ quoted := false
+ quote := '\x00'
+ i := 0
+ for _, rune := range s {
+ switch {
+ case escaped:
+ escaped = false
+ case rune == '\\':
+ escaped = true
+ continue
+ case quote != '\x00':
+ if rune == quote {
+ quote = '\x00'
+ continue
+ }
+ case rune == '"' || rune == '\'':
+ quoted = true
+ quote = rune
+ continue
+ case unicode.IsSpace(rune):
+ if quoted || i > 0 {
+ quoted = false
+ args = append(args, string(arg[:i]))
+ i = 0
+ }
+ continue
+ }
+ arg[i] = rune
+ i++
+ }
+ if quoted || i > 0 {
+ args = append(args, string(arg[:i]))
+ }
+ if quote != 0 {
+ err = errors.New("unclosed quote")
+ } else if escaped {
+ err = errors.New("unfinished escaping")
+ }
+ return args, err
+}
+
+// matchAuto interprets text as either a +build or //go:build expression (whichever works),
+// reporting whether the expression matches the build context.
+//
+// matchAuto is only used for testing of tag evaluation
+// and in #cgo lines, which accept either syntax.
+func (ctxt *Context) matchAuto(text string, allTags map[string]bool) bool {
+ if strings.ContainsAny(text, "&|()") {
+ text = "//go:build " + text
+ } else {
+ text = "// +build " + text
+ }
+ x, err := constraint.Parse(text)
+ if err != nil {
+ return false
+ }
+ return ctxt.eval(x, allTags)
+}
+
+func (ctxt *Context) eval(x constraint.Expr, allTags map[string]bool) bool {
+ return x.Eval(func(tag string) bool { return ctxt.matchTag(tag, allTags) })
+}
+
+// matchTag reports whether the name is one of:
+//
+// cgo (if cgo is enabled)
+// $GOOS
+// $GOARCH
+// boringcrypto
+// ctxt.Compiler
+// linux (if GOOS = android)
+// solaris (if GOOS = illumos)
+// tag (if tag is listed in ctxt.BuildTags or ctxt.ReleaseTags)
+//
+// It records all consulted tags in allTags.
+func (ctxt *Context) matchTag(name string, allTags map[string]bool) bool {
+ if allTags != nil {
+ allTags[name] = true
+ }
+
+ // special tags
+ if ctxt.CgoEnabled && name == "cgo" {
+ return true
+ }
+ if name == ctxt.GOOS || name == ctxt.GOARCH || name == ctxt.Compiler {
+ return true
+ }
+ if ctxt.GOOS == "android" && name == "linux" {
+ return true
+ }
+ if ctxt.GOOS == "illumos" && name == "solaris" {
+ return true
+ }
+ if ctxt.GOOS == "ios" && name == "darwin" {
+ return true
+ }
+ if name == "unix" && unixOS[ctxt.GOOS] {
+ return true
+ }
+ if name == "boringcrypto" {
+ name = "goexperiment.boringcrypto" // boringcrypto is an old name for goexperiment.boringcrypto
+ }
+
+ // other tags
+ for _, tag := range ctxt.BuildTags {
+ if tag == name {
+ return true
+ }
+ }
+ for _, tag := range ctxt.ToolTags {
+ if tag == name {
+ return true
+ }
+ }
+ for _, tag := range ctxt.ReleaseTags {
+ if tag == name {
+ return true
+ }
+ }
+
+ return false
+}
+
+// goodOSArchFile returns false if the name contains a $GOOS or $GOARCH
+// suffix which does not match the current system.
+// The recognized name formats are:
+//
+// name_$(GOOS).*
+// name_$(GOARCH).*
+// name_$(GOOS)_$(GOARCH).*
+// name_$(GOOS)_test.*
+// name_$(GOARCH)_test.*
+// name_$(GOOS)_$(GOARCH)_test.*
+//
+// Exceptions:
+// if GOOS=android, then files with GOOS=linux are also matched.
+// if GOOS=illumos, then files with GOOS=solaris are also matched.
+// if GOOS=ios, then files with GOOS=darwin are also matched.
+func (ctxt *Context) goodOSArchFile(name string, allTags map[string]bool) bool {
+ name, _, _ = strings.Cut(name, ".")
+
+ // Before Go 1.4, a file called "linux.go" would be equivalent to having a
+ // build tag "linux" in that file. For Go 1.4 and beyond, we require this
+ // auto-tagging to apply only to files with a non-empty prefix, so
+ // "foo_linux.go" is tagged but "linux.go" is not. This allows new operating
+ // systems, such as android, to arrive without breaking existing code with
+ // innocuous source code in "android.go". The easiest fix: cut everything
+ // in the name before the initial _.
+ i := strings.Index(name, "_")
+ if i < 0 {
+ return true
+ }
+ name = name[i:] // ignore everything before first _
+
+ l := strings.Split(name, "_")
+ if n := len(l); n > 0 && l[n-1] == "test" {
+ l = l[:n-1]
+ }
+ n := len(l)
+ if n >= 2 && knownOS[l[n-2]] && knownArch[l[n-1]] {
+ if allTags != nil {
+ // In case we short-circuit on l[n-1].
+ allTags[l[n-2]] = true
+ }
+ return ctxt.matchTag(l[n-1], allTags) && ctxt.matchTag(l[n-2], allTags)
+ }
+ if n >= 1 && (knownOS[l[n-1]] || knownArch[l[n-1]]) {
+ return ctxt.matchTag(l[n-1], allTags)
+ }
+ return true
+}
+
+// ToolDir is the directory containing build tools.
+var ToolDir = getToolDir()
+
+// IsLocalImport reports whether the import path is
+// a local import path, like ".", "..", "./foo", or "../foo".
+func IsLocalImport(path string) bool {
+ return path == "." || path == ".." ||
+ strings.HasPrefix(path, "./") || strings.HasPrefix(path, "../")
+}
+
+// ArchChar returns "?" and an error.
+// In earlier versions of Go, the returned string was used to derive
+// the compiler and linker tool names, the default object file suffix,
+// and the default linker output name. As of Go 1.5, those strings
+// no longer vary by architecture; they are compile, link, .o, and a.out, respectively.
+func ArchChar(goarch string) (string, error) {
+ return "?", errors.New("architecture letter no longer used")
+}