--- /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) {
+ 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 importPath := range imports {
+ deps[importPath] = true
+ }
+ imp.graphMu.Unlock()
+ }
+
+ var pending []*importInfo
+ for importPath := range imports {
+ if fromPath != "" {
+ if cycle := imp.findPath(importPath, fromPath); cycle != nil {
+ // Cycle-forming import: we must not check it
+ // since it would deadlock.
+ if trace {
+ fmt.Fprintf(os.Stderr, "import cycle: %q\n", cycle)
+ }
+ continue
+ }
+ }
+ 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))
+ }
+
+ for _, ii := range pending {
+ 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