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pkg.go
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pkg.go
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// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Package load loads packages.
package load
import (
"bytes"
"encoding/json"
"errors"
"fmt"
"go/build"
"go/scanner"
"go/token"
"io/ioutil"
"os"
pathpkg "path"
"path/filepath"
"runtime"
"sort"
"strconv"
"strings"
"unicode"
"unicode/utf8"
"cmd/go/internal/base"
"cmd/go/internal/cfg"
"cmd/go/internal/modinfo"
"cmd/go/internal/par"
"cmd/go/internal/search"
"cmd/go/internal/str"
)
var (
// module initialization hook; never nil, no-op if module use is disabled
ModInit func()
// module hooks; nil if module use is disabled
ModBinDir func() string // return effective bin directory
ModLookup func(parentPath string, parentIsStd bool, path string) (dir, realPath string, err error) // lookup effective meaning of import
ModPackageModuleInfo func(path string) *modinfo.ModulePublic // return module info for Package struct
ModImportPaths func(args []string) []*search.Match // expand import paths
ModPackageBuildInfo func(main string, deps []string) string // return module info to embed in binary
ModInfoProg func(info string, isgccgo bool) []byte // wrap module info in .go code for binary
ModImportFromFiles func([]string) // update go.mod to add modules for imports in these files
ModDirImportPath func(string) string // return effective import path for directory
)
var IgnoreImports bool // control whether we ignore imports in packages
// A Package describes a single package found in a directory.
type Package struct {
PackagePublic // visible in 'go list'
Internal PackageInternal // for use inside go command only
}
type PackagePublic struct {
// Note: These fields are part of the go command's public API.
// See list.go. It is okay to add fields, but not to change or
// remove existing ones. Keep in sync with list.go
Dir string `json:",omitempty"` // directory containing package sources
ImportPath string `json:",omitempty"` // import path of package in dir
ImportComment string `json:",omitempty"` // path in import comment on package statement
Name string `json:",omitempty"` // package name
Doc string `json:",omitempty"` // package documentation string
Target string `json:",omitempty"` // installed target for this package (may be executable)
Shlib string `json:",omitempty"` // the shared library that contains this package (only set when -linkshared)
Root string `json:",omitempty"` // Go root, Go path dir, or module root dir containing this package
ConflictDir string `json:",omitempty"` // Dir is hidden by this other directory
ForTest string `json:",omitempty"` // package is only for use in named test
Export string `json:",omitempty"` // file containing export data (set by go list -export)
Module *modinfo.ModulePublic `json:",omitempty"` // info about package's module, if any
Match []string `json:",omitempty"` // command-line patterns matching this package
Goroot bool `json:",omitempty"` // is this package found in the Go root?
Standard bool `json:",omitempty"` // is this package part of the standard Go library?
DepOnly bool `json:",omitempty"` // package is only as a dependency, not explicitly listed
BinaryOnly bool `json:",omitempty"` // package cannot be recompiled
Incomplete bool `json:",omitempty"` // was there an error loading this package or dependencies?
// Stale and StaleReason remain here *only* for the list command.
// They are only initialized in preparation for list execution.
// The regular build determines staleness on the fly during action execution.
Stale bool `json:",omitempty"` // would 'go install' do anything for this package?
StaleReason string `json:",omitempty"` // why is Stale true?
// Source files
// If you add to this list you MUST add to p.AllFiles (below) too.
// Otherwise file name security lists will not apply to any new additions.
GoFiles []string `json:",omitempty"` // .go source files (excluding CgoFiles, TestGoFiles, XTestGoFiles)
CgoFiles []string `json:",omitempty"` // .go source files that import "C"
CompiledGoFiles []string `json:",omitempty"` // .go output from running cgo on CgoFiles
IgnoredGoFiles []string `json:",omitempty"` // .go source files ignored due to build constraints
CFiles []string `json:",omitempty"` // .c source files
CXXFiles []string `json:",omitempty"` // .cc, .cpp and .cxx source files
MFiles []string `json:",omitempty"` // .m source files
HFiles []string `json:",omitempty"` // .h, .hh, .hpp and .hxx source files
FFiles []string `json:",omitempty"` // .f, .F, .for and .f90 Fortran source files
SFiles []string `json:",omitempty"` // .s source files
SwigFiles []string `json:",omitempty"` // .swig files
SwigCXXFiles []string `json:",omitempty"` // .swigcxx files
SysoFiles []string `json:",omitempty"` // .syso system object files added to package
// Cgo directives
CgoCFLAGS []string `json:",omitempty"` // cgo: flags for C compiler
CgoCPPFLAGS []string `json:",omitempty"` // cgo: flags for C preprocessor
CgoCXXFLAGS []string `json:",omitempty"` // cgo: flags for C++ compiler
CgoFFLAGS []string `json:",omitempty"` // cgo: flags for Fortran compiler
CgoLDFLAGS []string `json:",omitempty"` // cgo: flags for linker
CgoPkgConfig []string `json:",omitempty"` // cgo: pkg-config names
// Dependency information
Imports []string `json:",omitempty"` // import paths used by this package
ImportMap map[string]string `json:",omitempty"` // map from source import to ImportPath (identity entries omitted)
Deps []string `json:",omitempty"` // all (recursively) imported dependencies
// Error information
// Incomplete is above, packed into the other bools
Error *PackageError `json:",omitempty"` // error loading this package (not dependencies)
DepsErrors []*PackageError `json:",omitempty"` // errors loading dependencies
// Test information
// If you add to this list you MUST add to p.AllFiles (below) too.
// Otherwise file name security lists will not apply to any new additions.
TestGoFiles []string `json:",omitempty"` // _test.go files in package
TestImports []string `json:",omitempty"` // imports from TestGoFiles
XTestGoFiles []string `json:",omitempty"` // _test.go files outside package
XTestImports []string `json:",omitempty"` // imports from XTestGoFiles
}
// AllFiles returns the names of all the files considered for the package.
// This is used for sanity and security checks, so we include all files,
// even IgnoredGoFiles, because some subcommands consider them.
// The go/build package filtered others out (like foo_wrongGOARCH.s)
// and that's OK.
func (p *Package) AllFiles() []string {
return str.StringList(
p.GoFiles,
p.CgoFiles,
// no p.CompiledGoFiles, because they are from GoFiles or generated by us
p.IgnoredGoFiles,
p.CFiles,
p.CXXFiles,
p.MFiles,
p.HFiles,
p.FFiles,
p.SFiles,
p.SwigFiles,
p.SwigCXXFiles,
p.SysoFiles,
p.TestGoFiles,
p.XTestGoFiles,
)
}
// Desc returns the package "description", for use in b.showOutput.
func (p *Package) Desc() string {
if p.ForTest != "" {
return p.ImportPath + " [" + p.ForTest + ".test]"
}
return p.ImportPath
}
type PackageInternal struct {
// Unexported fields are not part of the public API.
Build *build.Package
Imports []*Package // this package's direct imports
CompiledImports []string // additional Imports necessary when using CompiledGoFiles (all from standard library)
RawImports []string // this package's original imports as they appear in the text of the program
ForceLibrary bool // this package is a library (even if named "main")
CmdlineFiles bool // package built from files listed on command line
CmdlinePkg bool // package listed on command line
CmdlinePkgLiteral bool // package listed as literal on command line (not via wildcard)
Local bool // imported via local path (./ or ../)
LocalPrefix string // interpret ./ and ../ imports relative to this prefix
ExeName string // desired name for temporary executable
CoverMode string // preprocess Go source files with the coverage tool in this mode
CoverVars map[string]*CoverVar // variables created by coverage analysis
OmitDebug bool // tell linker not to write debug information
GobinSubdir bool // install target would be subdir of GOBIN
BuildInfo string // add this info to package main
TestmainGo *[]byte // content for _testmain.go
Asmflags []string // -asmflags for this package
Gcflags []string // -gcflags for this package
Ldflags []string // -ldflags for this package
Gccgoflags []string // -gccgoflags for this package
}
type NoGoError struct {
Package *Package
}
func (e *NoGoError) Error() string {
// Count files beginning with _ and ., which we will pretend don't exist at all.
dummy := 0
for _, name := range e.Package.IgnoredGoFiles {
if strings.HasPrefix(name, "_") || strings.HasPrefix(name, ".") {
dummy++
}
}
if len(e.Package.IgnoredGoFiles) > dummy {
// Go files exist, but they were ignored due to build constraints.
return "build constraints exclude all Go files in " + e.Package.Dir
}
if len(e.Package.TestGoFiles)+len(e.Package.XTestGoFiles) > 0 {
// Test Go files exist, but we're not interested in them.
// The double-negative is unfortunate but we want e.Package.Dir
// to appear at the end of error message.
return "no non-test Go files in " + e.Package.Dir
}
return "no Go files in " + e.Package.Dir
}
// Resolve returns the resolved version of imports,
// which should be p.TestImports or p.XTestImports, NOT p.Imports.
// The imports in p.TestImports and p.XTestImports are not recursively
// loaded during the initial load of p, so they list the imports found in
// the source file, but most processing should be over the vendor-resolved
// import paths. We do this resolution lazily both to avoid file system work
// and because the eventual real load of the test imports (during 'go test')
// can produce better error messages if it starts with the original paths.
// The initial load of p loads all the non-test imports and rewrites
// the vendored paths, so nothing should ever call p.vendored(p.Imports).
func (p *Package) Resolve(imports []string) []string {
if len(imports) > 0 && len(p.Imports) > 0 && &imports[0] == &p.Imports[0] {
panic("internal error: p.Resolve(p.Imports) called")
}
seen := make(map[string]bool)
var all []string
for _, path := range imports {
path = ResolveImportPath(p, path)
if !seen[path] {
seen[path] = true
all = append(all, path)
}
}
sort.Strings(all)
return all
}
// CoverVar holds the name of the generated coverage variables targeting the named file.
type CoverVar struct {
File string // local file name
Var string // name of count struct
}
func (p *Package) copyBuild(pp *build.Package) {
p.Internal.Build = pp
if pp.PkgTargetRoot != "" && cfg.BuildPkgdir != "" {
old := pp.PkgTargetRoot
pp.PkgRoot = cfg.BuildPkgdir
pp.PkgTargetRoot = cfg.BuildPkgdir
pp.PkgObj = filepath.Join(cfg.BuildPkgdir, strings.TrimPrefix(pp.PkgObj, old))
}
p.Dir = pp.Dir
p.ImportPath = pp.ImportPath
p.ImportComment = pp.ImportComment
p.Name = pp.Name
p.Doc = pp.Doc
p.Root = pp.Root
p.ConflictDir = pp.ConflictDir
p.BinaryOnly = pp.BinaryOnly
// TODO? Target
p.Goroot = pp.Goroot
p.Standard = p.Goroot && p.ImportPath != "" && search.IsStandardImportPath(p.ImportPath)
p.GoFiles = pp.GoFiles
p.CgoFiles = pp.CgoFiles
p.IgnoredGoFiles = pp.IgnoredGoFiles
p.CFiles = pp.CFiles
p.CXXFiles = pp.CXXFiles
p.MFiles = pp.MFiles
p.HFiles = pp.HFiles
p.FFiles = pp.FFiles
p.SFiles = pp.SFiles
p.SwigFiles = pp.SwigFiles
p.SwigCXXFiles = pp.SwigCXXFiles
p.SysoFiles = pp.SysoFiles
p.CgoCFLAGS = pp.CgoCFLAGS
p.CgoCPPFLAGS = pp.CgoCPPFLAGS
p.CgoCXXFLAGS = pp.CgoCXXFLAGS
p.CgoFFLAGS = pp.CgoFFLAGS
p.CgoLDFLAGS = pp.CgoLDFLAGS
p.CgoPkgConfig = pp.CgoPkgConfig
// We modify p.Imports in place, so make copy now.
p.Imports = make([]string, len(pp.Imports))
copy(p.Imports, pp.Imports)
p.Internal.RawImports = pp.Imports
p.TestGoFiles = pp.TestGoFiles
p.TestImports = pp.TestImports
p.XTestGoFiles = pp.XTestGoFiles
p.XTestImports = pp.XTestImports
if IgnoreImports {
p.Imports = nil
p.Internal.RawImports = nil
p.TestImports = nil
p.XTestImports = nil
}
}
// A PackageError describes an error loading information about a package.
type PackageError struct {
ImportStack []string // shortest path from package named on command line to this one
Pos string // position of error
Err error // the error itself
IsImportCycle bool // the error is an import cycle
Hard bool // whether the error is soft or hard; soft errors are ignored in some places
}
func (p *PackageError) Error() string {
// Import cycles deserve special treatment.
if p.IsImportCycle {
return fmt.Sprintf("%s\npackage %s\n", p.Err, strings.Join(p.ImportStack, "\n\timports "))
}
if p.Pos != "" {
// Omit import stack. The full path to the file where the error
// is the most important thing.
return p.Pos + ": " + p.Err.Error()
}
// If the error is an ImportPathError, and the last path on the stack appears
// in the error message, omit that path from the stack to avoid repetition.
// If an ImportPathError wraps another ImportPathError that matches the
// last path on the stack, we don't omit the path. An error like
// "package A imports B: error loading C caused by B" would not be clearer
// if "imports B" were omitted.
stack := p.ImportStack
var ierr ImportPathError
if len(stack) > 0 && errors.As(p.Err, &ierr) && ierr.ImportPath() == stack[len(stack)-1] {
stack = stack[:len(stack)-1]
}
if len(stack) == 0 {
return p.Err.Error()
}
return "package " + strings.Join(stack, "\n\timports ") + ": " + p.Err.Error()
}
// PackageError implements MarshalJSON so that Err is marshaled as a string
// and non-essential fields are omitted.
func (p *PackageError) MarshalJSON() ([]byte, error) {
perr := struct {
ImportStack []string
Pos string
Err string
}{p.ImportStack, p.Pos, p.Err.Error()}
return json.Marshal(perr)
}
// ImportPathError is a type of error that prevents a package from being loaded
// for a given import path. When such a package is loaded, a *Package is
// returned with Err wrapping an ImportPathError: the error is attached to
// the imported package, not the importing package.
//
// The string returned by ImportPath must appear in the string returned by
// Error. Errors that wrap ImportPathError (such as PackageError) may omit
// the import path.
type ImportPathError interface {
error
ImportPath() string
}
type importError struct {
importPath string
err error // created with fmt.Errorf
}
var _ ImportPathError = (*importError)(nil)
func ImportErrorf(path, format string, args ...interface{}) ImportPathError {
err := &importError{importPath: path, err: fmt.Errorf(format, args...)}
if errStr := err.Error(); !strings.Contains(errStr, path) {
panic(fmt.Sprintf("path %q not in error %q", path, errStr))
}
return err
}
func (e *importError) Error() string {
return e.err.Error()
}
func (e *importError) Unwrap() error {
// Don't return e.err directly, since we're only wrapping an error if %w
// was passed to ImportErrorf.
return errors.Unwrap(e.err)
}
func (e *importError) ImportPath() string {
return e.importPath
}
// An ImportStack is a stack of import paths, possibly with the suffix " (test)" appended.
// The import path of a test package is the import path of the corresponding
// non-test package with the suffix "_test" added.
type ImportStack []string
func (s *ImportStack) Push(p string) {
*s = append(*s, p)
}
func (s *ImportStack) Pop() {
*s = (*s)[0 : len(*s)-1]
}
func (s *ImportStack) Copy() []string {
return append([]string{}, *s...)
}
// shorterThan reports whether sp is shorter than t.
// We use this to record the shortest import sequence
// that leads to a particular package.
func (sp *ImportStack) shorterThan(t []string) bool {
s := *sp
if len(s) != len(t) {
return len(s) < len(t)
}
// If they are the same length, settle ties using string ordering.
for i := range s {
if s[i] != t[i] {
return s[i] < t[i]
}
}
return false // they are equal
}
// packageCache is a lookup cache for LoadImport,
// so that if we look up a package multiple times
// we return the same pointer each time.
var packageCache = map[string]*Package{}
// ClearPackageCache clears the in-memory package cache and the preload caches.
// It is only for use by GOPATH-based "go get".
// TODO(jayconrod): When GOPATH-based "go get" is removed, delete this function.
func ClearPackageCache() {
for name := range packageCache {
delete(packageCache, name)
}
resolvedImportCache.Clear()
packageDataCache.Clear()
}
// ClearPackageCachePartial clears packages with the given import paths from the
// in-memory package cache and the preload caches. It is only for use by
// GOPATH-based "go get".
// TODO(jayconrod): When GOPATH-based "go get" is removed, delete this function.
func ClearPackageCachePartial(args []string) {
shouldDelete := make(map[string]bool)
for _, arg := range args {
shouldDelete[arg] = true
if p := packageCache[arg]; p != nil {
delete(packageCache, arg)
}
}
resolvedImportCache.DeleteIf(func(key interface{}) bool {
return shouldDelete[key.(importSpec).path]
})
packageDataCache.DeleteIf(func(key interface{}) bool {
return shouldDelete[key.(string)]
})
}
// ReloadPackageNoFlags is like LoadImport but makes sure
// not to use the package cache.
// It is only for use by GOPATH-based "go get".
// TODO(rsc): When GOPATH-based "go get" is removed, delete this function.
func ReloadPackageNoFlags(arg string, stk *ImportStack) *Package {
p := packageCache[arg]
if p != nil {
delete(packageCache, arg)
resolvedImportCache.DeleteIf(func(key interface{}) bool {
return key.(importSpec).path == p.ImportPath
})
packageDataCache.Delete(p.ImportPath)
}
return LoadImport(arg, base.Cwd, nil, stk, nil, 0)
}
// dirToImportPath returns the pseudo-import path we use for a package
// outside the Go path. It begins with _/ and then contains the full path
// to the directory. If the package lives in c:\home\gopher\my\pkg then
// the pseudo-import path is _/c_/home/gopher/my/pkg.
// Using a pseudo-import path like this makes the ./ imports no longer
// a special case, so that all the code to deal with ordinary imports works
// automatically.
func dirToImportPath(dir string) string {
return pathpkg.Join("_", strings.Map(makeImportValid, filepath.ToSlash(dir)))
}
func makeImportValid(r rune) rune {
// Should match Go spec, compilers, and ../../go/parser/parser.go:/isValidImport.
const illegalChars = `!"#$%&'()*,:;<=>?[\]^{|}` + "`\uFFFD"
if !unicode.IsGraphic(r) || unicode.IsSpace(r) || strings.ContainsRune(illegalChars, r) {
return '_'
}
return r
}
// Mode flags for loadImport and download (in get.go).
const (
// ResolveImport means that loadImport should do import path expansion.
// That is, ResolveImport means that the import path came from
// a source file and has not been expanded yet to account for
// vendoring or possible module adjustment.
// Every import path should be loaded initially with ResolveImport,
// and then the expanded version (for example with the /vendor/ in it)
// gets recorded as the canonical import path. At that point, future loads
// of that package must not pass ResolveImport, because
// disallowVendor will reject direct use of paths containing /vendor/.
ResolveImport = 1 << iota
// ResolveModule is for download (part of "go get") and indicates
// that the module adjustment should be done, but not vendor adjustment.
ResolveModule
// GetTestDeps is for download (part of "go get") and indicates
// that test dependencies should be fetched too.
GetTestDeps
)
// LoadImport scans the directory named by path, which must be an import path,
// but possibly a local import path (an absolute file system path or one beginning
// with ./ or ../). A local relative path is interpreted relative to srcDir.
// It returns a *Package describing the package found in that directory.
// LoadImport does not set tool flags and should only be used by
// this package, as part of a bigger load operation, and by GOPATH-based "go get".
// TODO(rsc): When GOPATH-based "go get" is removed, unexport this function.
func LoadImport(path, srcDir string, parent *Package, stk *ImportStack, importPos []token.Position, mode int) *Package {
return loadImport(nil, path, srcDir, parent, stk, importPos, mode)
}
func loadImport(pre *preload, path, srcDir string, parent *Package, stk *ImportStack, importPos []token.Position, mode int) *Package {
if path == "" {
panic("LoadImport called with empty package path")
}
stk.Push(path)
defer stk.Pop()
var parentPath, parentRoot string
parentIsStd := false
if parent != nil {
parentPath = parent.ImportPath
parentRoot = parent.Root
parentIsStd = parent.Standard
}
bp, loaded, err := loadPackageData(path, parentPath, srcDir, parentRoot, parentIsStd, mode)
if loaded && pre != nil && !IgnoreImports {
pre.preloadImports(bp.Imports, bp)
}
if bp == nil {
return &Package{
PackagePublic: PackagePublic{
ImportPath: path,
Error: &PackageError{
ImportStack: stk.Copy(),
Err: err,
},
},
}
}
importPath := bp.ImportPath
p := packageCache[importPath]
if p != nil {
p = reusePackage(p, stk)
} else {
p = new(Package)
p.Internal.Local = build.IsLocalImport(path)
p.ImportPath = importPath
packageCache[importPath] = p
// Load package.
// loadPackageData may return bp != nil even if an error occurs,
// in order to return partial information.
p.load(stk, bp, err)
if p.Error != nil && p.Error.Pos == "" {
p = setErrorPos(p, importPos)
}
if !cfg.ModulesEnabled && path != cleanImport(path) {
p.Error = &PackageError{
ImportStack: stk.Copy(),
Err: fmt.Errorf("non-canonical import path: %q should be %q", path, pathpkg.Clean(path)),
}
p.Incomplete = true
}
}
// Checked on every import because the rules depend on the code doing the importing.
if perr := disallowInternal(srcDir, parent, parentPath, p, stk); perr != p {
return setErrorPos(perr, importPos)
}
if mode&ResolveImport != 0 {
if perr := disallowVendor(srcDir, path, p, stk); perr != p {
return setErrorPos(perr, importPos)
}
}
if p.Name == "main" && parent != nil && parent.Dir != p.Dir {
perr := *p
perr.Error = &PackageError{
ImportStack: stk.Copy(),
Err: ImportErrorf(path, "import %q is a program, not an importable package", path),
}
return setErrorPos(&perr, importPos)
}
if p.Internal.Local && parent != nil && !parent.Internal.Local {
perr := *p
var err error
if path == "." {
err = ImportErrorf(path, "%s: cannot import current directory", path)
} else {
err = ImportErrorf(path, "local import %q in non-local package", path)
}
perr.Error = &PackageError{
ImportStack: stk.Copy(),
Err: err,
}
return setErrorPos(&perr, importPos)
}
return p
}
func setErrorPos(p *Package, importPos []token.Position) *Package {
if len(importPos) > 0 {
pos := importPos[0]
pos.Filename = base.ShortPath(pos.Filename)
p.Error.Pos = pos.String()
}
return p
}
// loadPackageData loads information needed to construct a *Package. The result
// is cached, and later calls to loadPackageData for the same package will return
// the same data.
//
// loadPackageData returns a non-nil package even if err is non-nil unless
// the package path is malformed (for example, the path contains "mod/" or "@").
//
// loadPackageData returns a boolean, loaded, which is true if this is the
// first time the package was loaded. Callers may preload imports in this case.
func loadPackageData(path, parentPath, parentDir, parentRoot string, parentIsStd bool, mode int) (bp *build.Package, loaded bool, err error) {
if path == "" {
panic("loadPackageData called with empty package path")
}
if strings.HasPrefix(path, "mod/") {
// Paths beginning with "mod/" might accidentally
// look in the module cache directory tree in $GOPATH/pkg/mod/.
// This prefix is owned by the Go core for possible use in the
// standard library (since it does not begin with a domain name),
// so it's OK to disallow entirely.
return nil, false, fmt.Errorf("disallowed import path %q", path)
}
if strings.Contains(path, "@") {
if cfg.ModulesEnabled {
return nil, false, errors.New("can only use path@version syntax with 'go get'")
} else {
return nil, false, errors.New("cannot use path@version syntax in GOPATH mode")
}
}
// Determine canonical package path and directory.
// For a local import the identifier is the pseudo-import path
// we create from the full directory to the package.
// Otherwise it is the usual import path.
// For vendored imports, it is the expanded form.
//
// Note that when modules are enabled, local import paths are normally
// canonicalized by modload.ImportPaths before now. However, if there's an
// error resolving a local path, it will be returned untransformed
// so that 'go list -e' reports something useful.
importKey := importSpec{
path: path,
parentPath: parentPath,
parentDir: parentDir,
parentRoot: parentRoot,
parentIsStd: parentIsStd,
mode: mode,
}
r := resolvedImportCache.Do(importKey, func() interface{} {
var r resolvedImport
if build.IsLocalImport(path) {
r.dir = filepath.Join(parentDir, path)
r.path = dirToImportPath(r.dir)
} else if cfg.ModulesEnabled {
r.dir, r.path, r.err = ModLookup(parentPath, parentIsStd, path)
} else if mode&ResolveImport != 0 {
// We do our own path resolution, because we want to
// find out the key to use in packageCache without the
// overhead of repeated calls to buildContext.Import.
// The code is also needed in a few other places anyway.
r.path = resolveImportPath(path, parentPath, parentDir, parentRoot, parentIsStd)
} else if mode&ResolveModule != 0 {
r.path = moduleImportPath(path, parentPath, parentDir, parentRoot)
}
if r.path == "" {
r.path = path
}
return r
}).(resolvedImport)
// Invariant: r.path is set to the resolved import path. If the path cannot
// be resolved, r.path is set to path, the source import path.
// r.path is never empty.
// Load the package from its directory. If we already found the package's
// directory when resolving its import path, use that.
data := packageDataCache.Do(r.path, func() interface{} {
loaded = true
var data packageData
if r.dir != "" {
var buildMode build.ImportMode
if !cfg.ModulesEnabled {
buildMode = build.ImportComment
}
data.p, data.err = cfg.BuildContext.ImportDir(r.dir, buildMode)
if data.p.Root == "" && cfg.ModulesEnabled {
if info := ModPackageModuleInfo(path); info != nil {
data.p.Root = info.Dir
}
}
} else if r.err != nil {
data.p = new(build.Package)
data.err = r.err
} else if cfg.ModulesEnabled && path != "unsafe" {
data.p = new(build.Package)
data.err = fmt.Errorf("unknown import path %q: internal error: module loader did not resolve import", r.path)
} else {
buildMode := build.ImportComment
if mode&ResolveImport == 0 || r.path != path {
// Not vendoring, or we already found the vendored path.
buildMode |= build.IgnoreVendor
}
data.p, data.err = cfg.BuildContext.Import(r.path, parentDir, buildMode)
}
data.p.ImportPath = r.path
// Set data.p.BinDir in cases where go/build.Context.Import
// may give us a path we don't want.
if !data.p.Goroot {
if cfg.GOBIN != "" {
data.p.BinDir = cfg.GOBIN
} else if cfg.ModulesEnabled {
data.p.BinDir = ModBinDir()
}
}
if !cfg.ModulesEnabled && data.err == nil &&
data.p.ImportComment != "" && data.p.ImportComment != path &&
!strings.Contains(path, "/vendor/") && !strings.HasPrefix(path, "vendor/") {
data.err = fmt.Errorf("code in directory %s expects import %q", data.p.Dir, data.p.ImportComment)
}
return data
}).(packageData)
return data.p, loaded, data.err
}
// importSpec describes an import declaration in source code. It is used as a
// cache key for resolvedImportCache.
type importSpec struct {
path string
parentPath, parentDir, parentRoot string
parentIsStd bool
mode int
}
// resolvedImport holds a canonical identifier for a package. It may also contain
// a path to the package's directory and an error if one occurred. resolvedImport
// is the value type in resolvedImportCache.
type resolvedImport struct {
path, dir string
err error
}
// packageData holds information loaded from a package. It is the value type
// in packageDataCache.
type packageData struct {
p *build.Package
err error
}
// resolvedImportCache maps import strings (importSpec) to canonical package names
// (resolvedImport).
var resolvedImportCache par.Cache
// packageDataCache maps canonical package names (string) to package metadata
// (packageData).
var packageDataCache par.Cache
// preloadWorkerCount is the number of concurrent goroutines that can load
// packages. Experimentally, there are diminishing returns with more than
// 4 workers. This was measured on the following machines.
//
// * MacBookPro with a 4-core Intel Core i7 CPU
// * Linux workstation with 6-core Intel Xeon CPU
// * Linux workstation with 24-core Intel Xeon CPU
//
// It is very likely (though not confirmed) that this workload is limited
// by memory bandwidth. We don't have a good way to determine the number of
// workers that would saturate the bus though, so runtime.GOMAXPROCS
// seems like a reasonable default.
var preloadWorkerCount = runtime.GOMAXPROCS(0)
// preload holds state for managing concurrent preloading of package data.
//
// A preload should be created with newPreload before loading a large
// package graph. flush must be called when package loading is complete
// to ensure preload goroutines are no longer active. This is necessary
// because of global mutable state that cannot safely be read and written
// concurrently. In particular, packageDataCache may be cleared by "go get"
// in GOPATH mode, and modload.loaded (accessed via ModLookup) may be
// modified by modload.ImportPaths (ModImportPaths).
type preload struct {
cancel chan struct{}
sema chan struct{}
}
// newPreload creates a new preloader. flush must be called later to avoid
// accessing global state while it is being modified.
func newPreload() *preload {
pre := &preload{
cancel: make(chan struct{}),
sema: make(chan struct{}, preloadWorkerCount),
}
return pre
}
// preloadMatches loads data for package paths matched by patterns.
// When preloadMatches returns, some packages may not be loaded yet, but
// loadPackageData and loadImport are always safe to call.
func (pre *preload) preloadMatches(matches []*search.Match) {
for _, m := range matches {
for _, pkg := range m.Pkgs {
select {
case <-pre.cancel:
return
case pre.sema <- struct{}{}:
go func(pkg string) {
mode := 0 // don't use vendoring or module import resolution
bp, loaded, err := loadPackageData(pkg, "", base.Cwd, "", false, mode)
<-pre.sema
if bp != nil && loaded && err == nil && !IgnoreImports {
pre.preloadImports(bp.Imports, bp)
}
}(pkg)
}
}
}
}
// preloadImports queues a list of imports for preloading.
// When preloadImports returns, some packages may not be loaded yet,
// but loadPackageData and loadImport are always safe to call.
func (pre *preload) preloadImports(imports []string, parent *build.Package) {
parentIsStd := parent.Goroot && parent.ImportPath != "" && search.IsStandardImportPath(parent.ImportPath)
for _, path := range imports {
if path == "C" || path == "unsafe" {
continue
}
select {
case <-pre.cancel:
return
case pre.sema <- struct{}{}:
go func(path string) {
bp, loaded, err := loadPackageData(path, parent.ImportPath, parent.Dir, parent.Root, parentIsStd, ResolveImport)
<-pre.sema
if bp != nil && loaded && err == nil && !IgnoreImports {
pre.preloadImports(bp.Imports, bp)
}
}(path)
}
}
}
// flush stops pending preload operations. flush blocks until preload calls to
// loadPackageData have completed. The preloader will not make any new calls
// to loadPackageData.
func (pre *preload) flush() {
close(pre.cancel)
for i := 0; i < preloadWorkerCount; i++ {
pre.sema <- struct{}{}
}
}
func cleanImport(path string) string {
orig := path
path = pathpkg.Clean(path)
if strings.HasPrefix(orig, "./") && path != ".." && !strings.HasPrefix(path, "../") {
path = "./" + path
}
return path
}
var isDirCache par.Cache
func isDir(path string) bool {
return isDirCache.Do(path, func() interface{} {
fi, err := os.Stat(path)
return err == nil && fi.IsDir()
}).(bool)
}
// ResolveImportPath returns the true meaning of path when it appears in parent.
// There are two different resolutions applied.
// First, there is Go 1.5 vendoring (golang.org/s/go15vendor).
// If vendor expansion doesn't trigger, then the path is also subject to
// Go 1.11 module legacy conversion (golang.org/issue/25069).
func ResolveImportPath(parent *Package, path string) (found string) {
var parentPath, parentDir, parentRoot string
parentIsStd := false
if parent != nil {
parentPath = parent.ImportPath
parentDir = parent.Dir
parentRoot = parent.Root
parentIsStd = parent.Standard
}
return resolveImportPath(path, parentPath, parentDir, parentRoot, parentIsStd)
}
func resolveImportPath(path, parentPath, parentDir, parentRoot string, parentIsStd bool) (found string) {
if cfg.ModulesEnabled {
if _, p, e := ModLookup(parentPath, parentIsStd, path); e == nil {
return p
}
return path
}
found = vendoredImportPath(path, parentPath, parentDir, parentRoot)
if found != path {
return found
}
return moduleImportPath(path, parentPath, parentDir, parentRoot)
}
// dirAndRoot returns the source directory and workspace root
// for the package p, guaranteeing that root is a path prefix of dir.
func dirAndRoot(path string, dir, root string) (string, string) {
origDir, origRoot := dir, root
dir = filepath.Clean(dir)
root = filepath.Join(root, "src")
if !str.HasFilePathPrefix(dir, root) || path != "command-line-arguments" && filepath.Join(root, path) != dir {
// Look for symlinks before reporting error.
dir = expandPath(dir)
root = expandPath(root)
}
if !str.HasFilePathPrefix(dir, root) || len(dir) <= len(root) || dir[len(root)] != filepath.Separator || path != "command-line-arguments" && !build.IsLocalImport(path) && filepath.Join(root, path) != dir {
base.Fatalf("unexpected directory layout:\n"+
" import path: %s\n"+
" root: %s\n"+
" dir: %s\n"+
" expand root: %s\n"+
" expand dir: %s\n"+
" separator: %s",
path,
filepath.Join(origRoot, "src"),
filepath.Clean(origDir),
origRoot,
origDir,
string(filepath.Separator))
}
return dir, root
}
// vendoredImportPath returns the vendor-expansion of path when it appears in parent.
// If parent is x/y/z, then path might expand to x/y/z/vendor/path, x/y/vendor/path,
// x/vendor/path, vendor/path, or else stay path if none of those exist.
// vendoredImportPath returns the expanded path or, if no expansion is found, the original.
func vendoredImportPath(path, parentPath, parentDir, parentRoot string) (found string) {
if parentRoot == "" {
return path
}
dir, root := dirAndRoot(parentPath, parentDir, parentRoot)
vpath := "vendor/" + path
for i := len(dir); i >= len(root); i-- {
if i < len(dir) && dir[i] != filepath.Separator {
continue
}
// Note: checking for the vendor directory before checking
// for the vendor/path directory helps us hit the
// isDir cache more often. It also helps us prepare a more useful
// list of places we looked, to report when an import is not found.
if !isDir(filepath.Join(dir[:i], "vendor")) {
continue
}
targ := filepath.Join(dir[:i], vpath)
if isDir(targ) && hasGoFiles(targ) {
importPath := parentPath
if importPath == "command-line-arguments" {
// If parent.ImportPath is 'command-line-arguments'.
// set to relative directory to root (also chopped root directory)