diff options
Diffstat (limited to 'vendor/golang.org/x/tools/go/loader/loader.go')
| -rw-r--r-- | vendor/golang.org/x/tools/go/loader/loader.go | 1077 |
1 files changed, 0 insertions, 1077 deletions
diff --git a/vendor/golang.org/x/tools/go/loader/loader.go b/vendor/golang.org/x/tools/go/loader/loader.go deleted file mode 100644 index de756f7..0000000 --- a/vendor/golang.org/x/tools/go/loader/loader.go +++ /dev/null @@ -1,1077 +0,0 @@ -// 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" -) - -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 := processCgoFiles(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://github.com/golang/go/issues/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 { - cycle = append([]string{fromPath}, cycle...) - 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) } |