+++ /dev/null
-// 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 loader
-
-// See doc.go for package documentation and implementation notes.
-
-import (
- "errors"
- "fmt"
- "go/ast"
- "go/build"
- "go/parser"
- "go/token"
- "go/types"
- "os"
- "path/filepath"
- "sort"
- "strings"
- "sync"
- "time"
-
- "golang.org/x/tools/go/ast/astutil"
- "golang.org/x/tools/go/internal/cgo"
-)
-
-var ignoreVendor build.ImportMode
-
-const trace = false // show timing info for type-checking
-
-// Config specifies the configuration for loading a whole program from
-// Go source code.
-// The zero value for Config is a ready-to-use default configuration.
-type Config struct {
- // Fset is the file set for the parser to use when loading the
- // program. If nil, it may be lazily initialized by any
- // method of Config.
- Fset *token.FileSet
-
- // ParserMode specifies the mode to be used by the parser when
- // loading source packages.
- ParserMode parser.Mode
-
- // TypeChecker contains options relating to the type checker.
- //
- // The supplied IgnoreFuncBodies is not used; the effective
- // value comes from the TypeCheckFuncBodies func below.
- // The supplied Import function is not used either.
- TypeChecker types.Config
-
- // TypeCheckFuncBodies is a predicate over package paths.
- // A package for which the predicate is false will
- // have its package-level declarations type checked, but not
- // its function bodies; this can be used to quickly load
- // dependencies from source. If nil, all func bodies are type
- // checked.
- TypeCheckFuncBodies func(path string) bool
-
- // If Build is non-nil, it is used to locate source packages.
- // Otherwise &build.Default is used.
- //
- // By default, cgo is invoked to preprocess Go files that
- // import the fake package "C". This behaviour can be
- // disabled by setting CGO_ENABLED=0 in the environment prior
- // to startup, or by setting Build.CgoEnabled=false.
- Build *build.Context
-
- // The current directory, used for resolving relative package
- // references such as "./go/loader". If empty, os.Getwd will be
- // used instead.
- Cwd string
-
- // If DisplayPath is non-nil, it is used to transform each
- // file name obtained from Build.Import(). This can be used
- // to prevent a virtualized build.Config's file names from
- // leaking into the user interface.
- DisplayPath func(path string) string
-
- // If AllowErrors is true, Load will return a Program even
- // if some of the its packages contained I/O, parser or type
- // errors; such errors are accessible via PackageInfo.Errors. If
- // false, Load will fail if any package had an error.
- AllowErrors bool
-
- // CreatePkgs specifies a list of non-importable initial
- // packages to create. The resulting packages will appear in
- // the corresponding elements of the Program.Created slice.
- CreatePkgs []PkgSpec
-
- // ImportPkgs specifies a set of initial packages to load.
- // The map keys are package paths.
- //
- // The map value indicates whether to load tests. If true, Load
- // will add and type-check two lists of files to the package:
- // non-test files followed by in-package *_test.go files. In
- // addition, it will append the external test package (if any)
- // to Program.Created.
- ImportPkgs map[string]bool
-
- // FindPackage is called during Load to create the build.Package
- // for a given import path from a given directory.
- // If FindPackage is nil, (*build.Context).Import is used.
- // A client may use this hook to adapt to a proprietary build
- // system that does not follow the "go build" layout
- // conventions, for example.
- //
- // It must be safe to call concurrently from multiple goroutines.
- FindPackage func(ctxt *build.Context, importPath, fromDir string, mode build.ImportMode) (*build.Package, error)
-
- // AfterTypeCheck is called immediately after a list of files
- // has been type-checked and appended to info.Files.
- //
- // This optional hook function is the earliest opportunity for
- // the client to observe the output of the type checker,
- // which may be useful to reduce analysis latency when loading
- // a large program.
- //
- // The function is permitted to modify info.Info, for instance
- // to clear data structures that are no longer needed, which can
- // dramatically reduce peak memory consumption.
- //
- // The function may be called twice for the same PackageInfo:
- // once for the files of the package and again for the
- // in-package test files.
- //
- // It must be safe to call concurrently from multiple goroutines.
- AfterTypeCheck func(info *PackageInfo, files []*ast.File)
-}
-
-// A PkgSpec specifies a non-importable package to be created by Load.
-// Files are processed first, but typically only one of Files and
-// Filenames is provided. The path needn't be globally unique.
-//
-// For vendoring purposes, the package's directory is the one that
-// contains the first file.
-type PkgSpec struct {
- Path string // package path ("" => use package declaration)
- Files []*ast.File // ASTs of already-parsed files
- Filenames []string // names of files to be parsed
-}
-
-// A Program is a Go program loaded from source as specified by a Config.
-type Program struct {
- Fset *token.FileSet // the file set for this program
-
- // Created[i] contains the initial package whose ASTs or
- // filenames were supplied by Config.CreatePkgs[i], followed by
- // the external test package, if any, of each package in
- // Config.ImportPkgs ordered by ImportPath.
- //
- // NOTE: these files must not import "C". Cgo preprocessing is
- // only performed on imported packages, not ad hoc packages.
- //
- // TODO(adonovan): we need to copy and adapt the logic of
- // goFilesPackage (from $GOROOT/src/cmd/go/build.go) and make
- // Config.Import and Config.Create methods return the same kind
- // of entity, essentially a build.Package.
- // Perhaps we can even reuse that type directly.
- Created []*PackageInfo
-
- // Imported contains the initially imported packages,
- // as specified by Config.ImportPkgs.
- Imported map[string]*PackageInfo
-
- // AllPackages contains the PackageInfo of every package
- // encountered by Load: all initial packages and all
- // dependencies, including incomplete ones.
- AllPackages map[*types.Package]*PackageInfo
-
- // importMap is the canonical mapping of package paths to
- // packages. It contains all Imported initial packages, but not
- // Created ones, and all imported dependencies.
- importMap map[string]*types.Package
-}
-
-// PackageInfo holds the ASTs and facts derived by the type-checker
-// for a single package.
-//
-// Not mutated once exposed via the API.
-//
-type PackageInfo struct {
- Pkg *types.Package
- Importable bool // true if 'import "Pkg.Path()"' would resolve to this
- TransitivelyErrorFree bool // true if Pkg and all its dependencies are free of errors
- Files []*ast.File // syntax trees for the package's files
- Errors []error // non-nil if the package had errors
- types.Info // type-checker deductions.
- dir string // package directory
-
- checker *types.Checker // transient type-checker state
- errorFunc func(error)
-}
-
-func (info *PackageInfo) String() string { return info.Pkg.Path() }
-
-func (info *PackageInfo) appendError(err error) {
- if info.errorFunc != nil {
- info.errorFunc(err)
- } else {
- fmt.Fprintln(os.Stderr, err)
- }
- info.Errors = append(info.Errors, err)
-}
-
-func (conf *Config) fset() *token.FileSet {
- if conf.Fset == nil {
- conf.Fset = token.NewFileSet()
- }
- return conf.Fset
-}
-
-// ParseFile is a convenience function (intended for testing) that invokes
-// the parser using the Config's FileSet, which is initialized if nil.
-//
-// src specifies the parser input as a string, []byte, or io.Reader, and
-// filename is its apparent name. If src is nil, the contents of
-// filename are read from the file system.
-//
-func (conf *Config) ParseFile(filename string, src interface{}) (*ast.File, error) {
- // TODO(adonovan): use conf.build() etc like parseFiles does.
- return parser.ParseFile(conf.fset(), filename, src, conf.ParserMode)
-}
-
-// FromArgsUsage is a partial usage message that applications calling
-// FromArgs may wish to include in their -help output.
-const FromArgsUsage = `
-<args> is a list of arguments denoting a set of initial packages.
-It may take one of two forms:
-
-1. A list of *.go source files.
-
- All of the specified files are loaded, parsed and type-checked
- as a single package. All the files must belong to the same directory.
-
-2. A list of import paths, each denoting a package.
-
- The package's directory is found relative to the $GOROOT and
- $GOPATH using similar logic to 'go build', and the *.go files in
- that directory are loaded, parsed and type-checked as a single
- package.
-
- In addition, all *_test.go files in the directory are then loaded
- and parsed. Those files whose package declaration equals that of
- the non-*_test.go files are included in the primary package. Test
- files whose package declaration ends with "_test" are type-checked
- as another package, the 'external' test package, so that a single
- import path may denote two packages. (Whether this behaviour is
- enabled is tool-specific, and may depend on additional flags.)
-
-A '--' argument terminates the list of packages.
-`
-
-// FromArgs interprets args as a set of initial packages to load from
-// source and updates the configuration. It returns the list of
-// unconsumed arguments.
-//
-// It is intended for use in command-line interfaces that require a
-// set of initial packages to be specified; see FromArgsUsage message
-// for details.
-//
-// Only superficial errors are reported at this stage; errors dependent
-// on I/O are detected during Load.
-//
-func (conf *Config) FromArgs(args []string, xtest bool) ([]string, error) {
- var rest []string
- for i, arg := range args {
- if arg == "--" {
- rest = args[i+1:]
- args = args[:i]
- break // consume "--" and return the remaining args
- }
- }
-
- if len(args) > 0 && strings.HasSuffix(args[0], ".go") {
- // Assume args is a list of a *.go files
- // denoting a single ad hoc package.
- for _, arg := range args {
- if !strings.HasSuffix(arg, ".go") {
- return nil, fmt.Errorf("named files must be .go files: %s", arg)
- }
- }
- conf.CreateFromFilenames("", args...)
- } else {
- // Assume args are directories each denoting a
- // package and (perhaps) an external test, iff xtest.
- for _, arg := range args {
- if xtest {
- conf.ImportWithTests(arg)
- } else {
- conf.Import(arg)
- }
- }
- }
-
- return rest, nil
-}
-
-// CreateFromFilenames is a convenience function that adds
-// a conf.CreatePkgs entry to create a package of the specified *.go
-// files.
-//
-func (conf *Config) CreateFromFilenames(path string, filenames ...string) {
- conf.CreatePkgs = append(conf.CreatePkgs, PkgSpec{Path: path, Filenames: filenames})
-}
-
-// CreateFromFiles is a convenience function that adds a conf.CreatePkgs
-// entry to create package of the specified path and parsed files.
-//
-func (conf *Config) CreateFromFiles(path string, files ...*ast.File) {
- conf.CreatePkgs = append(conf.CreatePkgs, PkgSpec{Path: path, Files: files})
-}
-
-// ImportWithTests is a convenience function that adds path to
-// ImportPkgs, the set of initial source packages located relative to
-// $GOPATH. The package will be augmented by any *_test.go files in
-// its directory that contain a "package x" (not "package x_test")
-// declaration.
-//
-// In addition, if any *_test.go files contain a "package x_test"
-// declaration, an additional package comprising just those files will
-// be added to CreatePkgs.
-//
-func (conf *Config) ImportWithTests(path string) { conf.addImport(path, true) }
-
-// Import is a convenience function that adds path to ImportPkgs, the
-// set of initial packages that will be imported from source.
-//
-func (conf *Config) Import(path string) { conf.addImport(path, false) }
-
-func (conf *Config) addImport(path string, tests bool) {
- if path == "C" {
- return // ignore; not a real package
- }
- if conf.ImportPkgs == nil {
- conf.ImportPkgs = make(map[string]bool)
- }
- conf.ImportPkgs[path] = conf.ImportPkgs[path] || tests
-}
-
-// PathEnclosingInterval returns the PackageInfo and ast.Node that
-// contain source interval [start, end), and all the node's ancestors
-// up to the AST root. It searches all ast.Files of all packages in prog.
-// exact is defined as for astutil.PathEnclosingInterval.
-//
-// The zero value is returned if not found.
-//
-func (prog *Program) PathEnclosingInterval(start, end token.Pos) (pkg *PackageInfo, path []ast.Node, exact bool) {
- for _, info := range prog.AllPackages {
- for _, f := range info.Files {
- if f.Pos() == token.NoPos {
- // This can happen if the parser saw
- // too many errors and bailed out.
- // (Use parser.AllErrors to prevent that.)
- continue
- }
- if !tokenFileContainsPos(prog.Fset.File(f.Pos()), start) {
- continue
- }
- if path, exact := astutil.PathEnclosingInterval(f, start, end); path != nil {
- return info, path, exact
- }
- }
- }
- return nil, nil, false
-}
-
-// InitialPackages returns a new slice containing the set of initial
-// packages (Created + Imported) in unspecified order.
-//
-func (prog *Program) InitialPackages() []*PackageInfo {
- infos := make([]*PackageInfo, 0, len(prog.Created)+len(prog.Imported))
- infos = append(infos, prog.Created...)
- for _, info := range prog.Imported {
- infos = append(infos, info)
- }
- return infos
-}
-
-// Package returns the ASTs and results of type checking for the
-// specified package.
-func (prog *Program) Package(path string) *PackageInfo {
- if info, ok := prog.AllPackages[prog.importMap[path]]; ok {
- return info
- }
- for _, info := range prog.Created {
- if path == info.Pkg.Path() {
- return info
- }
- }
- return nil
-}
-
-// ---------- Implementation ----------
-
-// importer holds the working state of the algorithm.
-type importer struct {
- conf *Config // the client configuration
- start time.Time // for logging
-
- progMu sync.Mutex // guards prog
- prog *Program // the resulting program
-
- // findpkg is a memoization of FindPackage.
- findpkgMu sync.Mutex // guards findpkg
- findpkg map[findpkgKey]*findpkgValue
-
- importedMu sync.Mutex // guards imported
- imported map[string]*importInfo // all imported packages (incl. failures) by import path
-
- // import dependency graph: graph[x][y] => x imports y
- //
- // Since non-importable packages cannot be cyclic, we ignore
- // their imports, thus we only need the subgraph over importable
- // packages. Nodes are identified by their import paths.
- graphMu sync.Mutex
- graph map[string]map[string]bool
-}
-
-type findpkgKey struct {
- importPath string
- fromDir string
- mode build.ImportMode
-}
-
-type findpkgValue struct {
- ready chan struct{} // closed to broadcast readiness
- bp *build.Package
- err error
-}
-
-// importInfo tracks the success or failure of a single import.
-//
-// Upon completion, exactly one of info and err is non-nil:
-// info on successful creation of a package, err otherwise.
-// A successful package may still contain type errors.
-//
-type importInfo struct {
- path string // import path
- info *PackageInfo // results of typechecking (including errors)
- complete chan struct{} // closed to broadcast that info is set.
-}
-
-// awaitCompletion blocks until ii is complete,
-// i.e. the info field is safe to inspect.
-func (ii *importInfo) awaitCompletion() {
- <-ii.complete // wait for close
-}
-
-// Complete marks ii as complete.
-// Its info and err fields will not be subsequently updated.
-func (ii *importInfo) Complete(info *PackageInfo) {
- if info == nil {
- panic("info == nil")
- }
- ii.info = info
- close(ii.complete)
-}
-
-type importError struct {
- path string // import path
- err error // reason for failure to create a package
-}
-
-// Load creates the initial packages specified by conf.{Create,Import}Pkgs,
-// loading their dependencies packages as needed.
-//
-// On success, Load returns a Program containing a PackageInfo for
-// each package. On failure, it returns an error.
-//
-// If AllowErrors is true, Load will return a Program even if some
-// packages contained I/O, parser or type errors, or if dependencies
-// were missing. (Such errors are accessible via PackageInfo.Errors. If
-// false, Load will fail if any package had an error.
-//
-// It is an error if no packages were loaded.
-//
-func (conf *Config) Load() (*Program, error) {
- // Create a simple default error handler for parse/type errors.
- if conf.TypeChecker.Error == nil {
- conf.TypeChecker.Error = func(e error) { fmt.Fprintln(os.Stderr, e) }
- }
-
- // Set default working directory for relative package references.
- if conf.Cwd == "" {
- var err error
- conf.Cwd, err = os.Getwd()
- if err != nil {
- return nil, err
- }
- }
-
- // Install default FindPackage hook using go/build logic.
- if conf.FindPackage == nil {
- conf.FindPackage = (*build.Context).Import
- }
-
- prog := &Program{
- Fset: conf.fset(),
- Imported: make(map[string]*PackageInfo),
- importMap: make(map[string]*types.Package),
- AllPackages: make(map[*types.Package]*PackageInfo),
- }
-
- imp := importer{
- conf: conf,
- prog: prog,
- findpkg: make(map[findpkgKey]*findpkgValue),
- imported: make(map[string]*importInfo),
- start: time.Now(),
- graph: make(map[string]map[string]bool),
- }
-
- // -- loading proper (concurrent phase) --------------------------------
-
- var errpkgs []string // packages that contained errors
-
- // Load the initially imported packages and their dependencies,
- // in parallel.
- // No vendor check on packages imported from the command line.
- infos, importErrors := imp.importAll("", conf.Cwd, conf.ImportPkgs, ignoreVendor)
- for _, ie := range importErrors {
- conf.TypeChecker.Error(ie.err) // failed to create package
- errpkgs = append(errpkgs, ie.path)
- }
- for _, info := range infos {
- prog.Imported[info.Pkg.Path()] = info
- }
-
- // Augment the designated initial packages by their tests.
- // Dependencies are loaded in parallel.
- var xtestPkgs []*build.Package
- for importPath, augment := range conf.ImportPkgs {
- if !augment {
- continue
- }
-
- // No vendor check on packages imported from command line.
- bp, err := imp.findPackage(importPath, conf.Cwd, ignoreVendor)
- if err != nil {
- // Package not found, or can't even parse package declaration.
- // Already reported by previous loop; ignore it.
- continue
- }
-
- // Needs external test package?
- if len(bp.XTestGoFiles) > 0 {
- xtestPkgs = append(xtestPkgs, bp)
- }
-
- // Consult the cache using the canonical package path.
- path := bp.ImportPath
- imp.importedMu.Lock() // (unnecessary, we're sequential here)
- ii, ok := imp.imported[path]
- // Paranoid checks added due to issue #11012.
- if !ok {
- // Unreachable.
- // The previous loop called importAll and thus
- // startLoad for each path in ImportPkgs, which
- // populates imp.imported[path] with a non-zero value.
- panic(fmt.Sprintf("imported[%q] not found", path))
- }
- if ii == nil {
- // Unreachable.
- // The ii values in this loop are the same as in
- // the previous loop, which enforced the invariant
- // that at least one of ii.err and ii.info is non-nil.
- panic(fmt.Sprintf("imported[%q] == nil", path))
- }
- if ii.info == nil {
- // Unreachable.
- // awaitCompletion has the postcondition
- // ii.info != nil.
- panic(fmt.Sprintf("imported[%q].info = nil", path))
- }
- info := ii.info
- imp.importedMu.Unlock()
-
- // Parse the in-package test files.
- files, errs := imp.conf.parsePackageFiles(bp, 't')
- for _, err := range errs {
- info.appendError(err)
- }
-
- // The test files augmenting package P cannot be imported,
- // but may import packages that import P,
- // so we must disable the cycle check.
- imp.addFiles(info, files, false)
- }
-
- createPkg := func(path, dir string, files []*ast.File, errs []error) {
- info := imp.newPackageInfo(path, dir)
- for _, err := range errs {
- info.appendError(err)
- }
-
- // Ad hoc packages are non-importable,
- // so no cycle check is needed.
- // addFiles loads dependencies in parallel.
- imp.addFiles(info, files, false)
- prog.Created = append(prog.Created, info)
- }
-
- // Create packages specified by conf.CreatePkgs.
- for _, cp := range conf.CreatePkgs {
- files, errs := parseFiles(conf.fset(), conf.build(), nil, conf.Cwd, cp.Filenames, conf.ParserMode)
- files = append(files, cp.Files...)
-
- path := cp.Path
- if path == "" {
- if len(files) > 0 {
- path = files[0].Name.Name
- } else {
- path = "(unnamed)"
- }
- }
-
- dir := conf.Cwd
- if len(files) > 0 && files[0].Pos().IsValid() {
- dir = filepath.Dir(conf.fset().File(files[0].Pos()).Name())
- }
- createPkg(path, dir, files, errs)
- }
-
- // Create external test packages.
- sort.Sort(byImportPath(xtestPkgs))
- for _, bp := range xtestPkgs {
- files, errs := imp.conf.parsePackageFiles(bp, 'x')
- createPkg(bp.ImportPath+"_test", bp.Dir, files, errs)
- }
-
- // -- finishing up (sequential) ----------------------------------------
-
- if len(prog.Imported)+len(prog.Created) == 0 {
- return nil, errors.New("no initial packages were loaded")
- }
-
- // Create infos for indirectly imported packages.
- // e.g. incomplete packages without syntax, loaded from export data.
- for _, obj := range prog.importMap {
- info := prog.AllPackages[obj]
- if info == nil {
- prog.AllPackages[obj] = &PackageInfo{Pkg: obj, Importable: true}
- } else {
- // finished
- info.checker = nil
- info.errorFunc = nil
- }
- }
-
- if !conf.AllowErrors {
- // Report errors in indirectly imported packages.
- for _, info := range prog.AllPackages {
- if len(info.Errors) > 0 {
- errpkgs = append(errpkgs, info.Pkg.Path())
- }
- }
- if errpkgs != nil {
- var more string
- if len(errpkgs) > 3 {
- more = fmt.Sprintf(" and %d more", len(errpkgs)-3)
- errpkgs = errpkgs[:3]
- }
- return nil, fmt.Errorf("couldn't load packages due to errors: %s%s",
- strings.Join(errpkgs, ", "), more)
- }
- }
-
- markErrorFreePackages(prog.AllPackages)
-
- return prog, nil
-}
-
-type byImportPath []*build.Package
-
-func (b byImportPath) Len() int { return len(b) }
-func (b byImportPath) Less(i, j int) bool { return b[i].ImportPath < b[j].ImportPath }
-func (b byImportPath) Swap(i, j int) { b[i], b[j] = b[j], b[i] }
-
-// markErrorFreePackages sets the TransitivelyErrorFree flag on all
-// applicable packages.
-func markErrorFreePackages(allPackages map[*types.Package]*PackageInfo) {
- // Build the transpose of the import graph.
- importedBy := make(map[*types.Package]map[*types.Package]bool)
- for P := range allPackages {
- for _, Q := range P.Imports() {
- clients, ok := importedBy[Q]
- if !ok {
- clients = make(map[*types.Package]bool)
- importedBy[Q] = clients
- }
- clients[P] = true
- }
- }
-
- // Find all packages reachable from some error package.
- reachable := make(map[*types.Package]bool)
- var visit func(*types.Package)
- visit = func(p *types.Package) {
- if !reachable[p] {
- reachable[p] = true
- for q := range importedBy[p] {
- visit(q)
- }
- }
- }
- for _, info := range allPackages {
- if len(info.Errors) > 0 {
- visit(info.Pkg)
- }
- }
-
- // Mark the others as "transitively error-free".
- for _, info := range allPackages {
- if !reachable[info.Pkg] {
- info.TransitivelyErrorFree = true
- }
- }
-}
-
-// build returns the effective build context.
-func (conf *Config) build() *build.Context {
- if conf.Build != nil {
- return conf.Build
- }
- return &build.Default
-}
-
-// parsePackageFiles enumerates the files belonging to package path,
-// then loads, parses and returns them, plus a list of I/O or parse
-// errors that were encountered.
-//
-// 'which' indicates which files to include:
-// 'g': include non-test *.go source files (GoFiles + processed CgoFiles)
-// 't': include in-package *_test.go source files (TestGoFiles)
-// 'x': include external *_test.go source files. (XTestGoFiles)
-//
-func (conf *Config) parsePackageFiles(bp *build.Package, which rune) ([]*ast.File, []error) {
- if bp.ImportPath == "unsafe" {
- return nil, nil
- }
- var filenames []string
- switch which {
- case 'g':
- filenames = bp.GoFiles
- case 't':
- filenames = bp.TestGoFiles
- case 'x':
- filenames = bp.XTestGoFiles
- default:
- panic(which)
- }
-
- files, errs := parseFiles(conf.fset(), conf.build(), conf.DisplayPath, bp.Dir, filenames, conf.ParserMode)
-
- // Preprocess CgoFiles and parse the outputs (sequentially).
- if which == 'g' && bp.CgoFiles != nil {
- cgofiles, err := cgo.ProcessFiles(bp, conf.fset(), conf.DisplayPath, conf.ParserMode)
- if err != nil {
- errs = append(errs, err)
- } else {
- files = append(files, cgofiles...)
- }
- }
-
- return files, errs
-}
-
-// doImport imports the package denoted by path.
-// It implements the types.Importer signature.
-//
-// It returns an error if a package could not be created
-// (e.g. go/build or parse error), but type errors are reported via
-// the types.Config.Error callback (the first of which is also saved
-// in the package's PackageInfo).
-//
-// Idempotent.
-//
-func (imp *importer) doImport(from *PackageInfo, to string) (*types.Package, error) {
- if to == "C" {
- // This should be unreachable, but ad hoc packages are
- // not currently subject to cgo preprocessing.
- // See https://golang.org/issue/11627.
- return nil, fmt.Errorf(`the loader doesn't cgo-process ad hoc packages like %q; see Go issue 11627`,
- from.Pkg.Path())
- }
-
- bp, err := imp.findPackage(to, from.dir, 0)
- if err != nil {
- return nil, err
- }
-
- // The standard unsafe package is handled specially,
- // and has no PackageInfo.
- if bp.ImportPath == "unsafe" {
- return types.Unsafe, nil
- }
-
- // Look for the package in the cache using its canonical path.
- path := bp.ImportPath
- imp.importedMu.Lock()
- ii := imp.imported[path]
- imp.importedMu.Unlock()
- if ii == nil {
- panic("internal error: unexpected import: " + path)
- }
- if ii.info != nil {
- return ii.info.Pkg, nil
- }
-
- // Import of incomplete package: this indicates a cycle.
- fromPath := from.Pkg.Path()
- if cycle := imp.findPath(path, fromPath); cycle != nil {
- // Normalize cycle: start from alphabetically largest node.
- pos, start := -1, ""
- for i, s := range cycle {
- if pos < 0 || s > start {
- pos, start = i, s
- }
- }
- cycle = append(cycle, cycle[:pos]...)[pos:] // rotate cycle to start from largest
- cycle = append(cycle, cycle[0]) // add start node to end to show cycliness
- return nil, fmt.Errorf("import cycle: %s", strings.Join(cycle, " -> "))
- }
-
- panic("internal error: import of incomplete (yet acyclic) package: " + fromPath)
-}
-
-// findPackage locates the package denoted by the importPath in the
-// specified directory.
-func (imp *importer) findPackage(importPath, fromDir string, mode build.ImportMode) (*build.Package, error) {
- // We use a non-blocking duplicate-suppressing cache (gopl.io ยง9.7)
- // to avoid holding the lock around FindPackage.
- key := findpkgKey{importPath, fromDir, mode}
- imp.findpkgMu.Lock()
- v, ok := imp.findpkg[key]
- if ok {
- // cache hit
- imp.findpkgMu.Unlock()
-
- <-v.ready // wait for entry to become ready
- } else {
- // Cache miss: this goroutine becomes responsible for
- // populating the map entry and broadcasting its readiness.
- v = &findpkgValue{ready: make(chan struct{})}
- imp.findpkg[key] = v
- imp.findpkgMu.Unlock()
-
- ioLimit <- true
- v.bp, v.err = imp.conf.FindPackage(imp.conf.build(), importPath, fromDir, mode)
- <-ioLimit
-
- if _, ok := v.err.(*build.NoGoError); ok {
- v.err = nil // empty directory is not an error
- }
-
- close(v.ready) // broadcast ready condition
- }
- return v.bp, v.err
-}
-
-// importAll loads, parses, and type-checks the specified packages in
-// parallel and returns their completed importInfos in unspecified order.
-//
-// fromPath is the package path of the importing package, if it is
-// importable, "" otherwise. It is used for cycle detection.
-//
-// fromDir is the directory containing the import declaration that
-// caused these imports.
-//
-func (imp *importer) importAll(fromPath, fromDir string, imports map[string]bool, mode build.ImportMode) (infos []*PackageInfo, errors []importError) {
- // TODO(adonovan): opt: do the loop in parallel once
- // findPackage is non-blocking.
- var pending []*importInfo
- for importPath := range imports {
- bp, err := imp.findPackage(importPath, fromDir, mode)
- if err != nil {
- errors = append(errors, importError{
- path: importPath,
- err: err,
- })
- continue
- }
- pending = append(pending, imp.startLoad(bp))
- }
-
- if fromPath != "" {
- // We're loading a set of imports.
- //
- // We must record graph edges from the importing package
- // to its dependencies, and check for cycles.
- imp.graphMu.Lock()
- deps, ok := imp.graph[fromPath]
- if !ok {
- deps = make(map[string]bool)
- imp.graph[fromPath] = deps
- }
- for _, ii := range pending {
- deps[ii.path] = true
- }
- imp.graphMu.Unlock()
- }
-
- for _, ii := range pending {
- if fromPath != "" {
- if cycle := imp.findPath(ii.path, fromPath); cycle != nil {
- // Cycle-forming import: we must not await its
- // completion since it would deadlock.
- //
- // We don't record the error in ii since
- // the error is really associated with the
- // cycle-forming edge, not the package itself.
- // (Also it would complicate the
- // invariants of importPath completion.)
- if trace {
- fmt.Fprintf(os.Stderr, "import cycle: %q\n", cycle)
- }
- continue
- }
- }
- ii.awaitCompletion()
- infos = append(infos, ii.info)
- }
-
- return infos, errors
-}
-
-// findPath returns an arbitrary path from 'from' to 'to' in the import
-// graph, or nil if there was none.
-func (imp *importer) findPath(from, to string) []string {
- imp.graphMu.Lock()
- defer imp.graphMu.Unlock()
-
- seen := make(map[string]bool)
- var search func(stack []string, importPath string) []string
- search = func(stack []string, importPath string) []string {
- if !seen[importPath] {
- seen[importPath] = true
- stack = append(stack, importPath)
- if importPath == to {
- return stack
- }
- for x := range imp.graph[importPath] {
- if p := search(stack, x); p != nil {
- return p
- }
- }
- }
- return nil
- }
- return search(make([]string, 0, 20), from)
-}
-
-// startLoad initiates the loading, parsing and type-checking of the
-// specified package and its dependencies, if it has not already begun.
-//
-// It returns an importInfo, not necessarily in a completed state. The
-// caller must call awaitCompletion() before accessing its info field.
-//
-// startLoad is concurrency-safe and idempotent.
-//
-func (imp *importer) startLoad(bp *build.Package) *importInfo {
- path := bp.ImportPath
- imp.importedMu.Lock()
- ii, ok := imp.imported[path]
- if !ok {
- ii = &importInfo{path: path, complete: make(chan struct{})}
- imp.imported[path] = ii
- go func() {
- info := imp.load(bp)
- ii.Complete(info)
- }()
- }
- imp.importedMu.Unlock()
-
- return ii
-}
-
-// load implements package loading by parsing Go source files
-// located by go/build.
-func (imp *importer) load(bp *build.Package) *PackageInfo {
- info := imp.newPackageInfo(bp.ImportPath, bp.Dir)
- info.Importable = true
- files, errs := imp.conf.parsePackageFiles(bp, 'g')
- for _, err := range errs {
- info.appendError(err)
- }
-
- imp.addFiles(info, files, true)
-
- imp.progMu.Lock()
- imp.prog.importMap[bp.ImportPath] = info.Pkg
- imp.progMu.Unlock()
-
- return info
-}
-
-// addFiles adds and type-checks the specified files to info, loading
-// their dependencies if needed. The order of files determines the
-// package initialization order. It may be called multiple times on the
-// same package. Errors are appended to the info.Errors field.
-//
-// cycleCheck determines whether the imports within files create
-// dependency edges that should be checked for potential cycles.
-//
-func (imp *importer) addFiles(info *PackageInfo, files []*ast.File, cycleCheck bool) {
- // Ensure the dependencies are loaded, in parallel.
- var fromPath string
- if cycleCheck {
- fromPath = info.Pkg.Path()
- }
- // TODO(adonovan): opt: make the caller do scanImports.
- // Callers with a build.Package can skip it.
- imp.importAll(fromPath, info.dir, scanImports(files), 0)
-
- if trace {
- fmt.Fprintf(os.Stderr, "%s: start %q (%d)\n",
- time.Since(imp.start), info.Pkg.Path(), len(files))
- }
-
- // Don't call checker.Files on Unsafe, even with zero files,
- // because it would mutate the package, which is a global.
- if info.Pkg == types.Unsafe {
- if len(files) > 0 {
- panic(`"unsafe" package contains unexpected files`)
- }
- } else {
- // Ignore the returned (first) error since we
- // already collect them all in the PackageInfo.
- info.checker.Files(files)
- info.Files = append(info.Files, files...)
- }
-
- if imp.conf.AfterTypeCheck != nil {
- imp.conf.AfterTypeCheck(info, files)
- }
-
- if trace {
- fmt.Fprintf(os.Stderr, "%s: stop %q\n",
- time.Since(imp.start), info.Pkg.Path())
- }
-}
-
-func (imp *importer) newPackageInfo(path, dir string) *PackageInfo {
- var pkg *types.Package
- if path == "unsafe" {
- pkg = types.Unsafe
- } else {
- pkg = types.NewPackage(path, "")
- }
- info := &PackageInfo{
- Pkg: pkg,
- Info: types.Info{
- Types: make(map[ast.Expr]types.TypeAndValue),
- Defs: make(map[*ast.Ident]types.Object),
- Uses: make(map[*ast.Ident]types.Object),
- Implicits: make(map[ast.Node]types.Object),
- Scopes: make(map[ast.Node]*types.Scope),
- Selections: make(map[*ast.SelectorExpr]*types.Selection),
- },
- errorFunc: imp.conf.TypeChecker.Error,
- dir: dir,
- }
-
- // Copy the types.Config so we can vary it across PackageInfos.
- tc := imp.conf.TypeChecker
- tc.IgnoreFuncBodies = false
- if f := imp.conf.TypeCheckFuncBodies; f != nil {
- tc.IgnoreFuncBodies = !f(path)
- }
- tc.Importer = closure{imp, info}
- tc.Error = info.appendError // appendError wraps the user's Error function
-
- info.checker = types.NewChecker(&tc, imp.conf.fset(), pkg, &info.Info)
- imp.progMu.Lock()
- imp.prog.AllPackages[pkg] = info
- imp.progMu.Unlock()
- return info
-}
-
-type closure struct {
- imp *importer
- info *PackageInfo
-}
-
-func (c closure) Import(to string) (*types.Package, error) { return c.imp.doImport(c.info, to) }
projects / dotfiles / .git / blobdiff