package imports
import (
"bytes"
"encoding/json"
"io/ioutil"
"log"
"os"
"path"
"path/filepath"
"regexp"
"sort"
"strconv"
"strings"
"sync"
"time"
"golang.org/x/tools/internal/gopathwalk"
"golang.org/x/tools/internal/module"
)
// moduleResolver implements resolver for modules using the go command as little
// as feasible.
type moduleResolver struct {
env *fixEnv
initialized bool
main *moduleJSON
modsByModPath []*moduleJSON // All modules, ordered by # of path components in module Path...
modsByDir []*moduleJSON // ...or Dir.
}
type moduleJSON struct {
Path string // module path
Version string // module version
Versions []string // available module versions (with -versions)
Replace *moduleJSON // replaced by this module
Time *time.Time // time version was created
Update *moduleJSON // available update, if any (with -u)
Main bool // is this the main module?
Indirect bool // is this module only an indirect dependency of main module?
Dir string // directory holding files for this module, if any
GoMod string // path to go.mod file for this module, if any
Error *moduleErrorJSON // error loading module
}
type moduleErrorJSON struct {
Err string // the error itself
}
func (r *moduleResolver) init() error {
if r.initialized {
return nil
}
stdout, err := r.env.invokeGo("list", "-m", "-json", "...")
if err != nil {
return err
}
for dec := json.NewDecoder(stdout); dec.More(); {
mod := &moduleJSON{}
if err := dec.Decode(mod); err != nil {
return err
}
if mod.Dir == "" {
if Debug {
log.Printf("module %v has not been downloaded and will be ignored", mod.Path)
}
// Can't do anything with a module that's not downloaded.
continue
}
r.modsByModPath = append(r.modsByModPath, mod)
r.modsByDir = append(r.modsByDir, mod)
if mod.Main {
r.main = mod
}
}
sort.Slice(r.modsByModPath, func(i, j int) bool {
count := func(x int) int {
return strings.Count(r.modsByModPath[x].Path, "/")
}
return count(j) < count(i) // descending order
})
sort.Slice(r.modsByDir, func(i, j int) bool {
count := func(x int) int {
return strings.Count(r.modsByDir[x].Dir, "/")
}
return count(j) < count(i) // descending order
})
r.initialized = true
return nil
}
// findPackage returns the module and directory that contains the package at
// the given import path, or returns nil, "" if no module is in scope.
func (r *moduleResolver) findPackage(importPath string) (*moduleJSON, string) {
for _, m := range r.modsByModPath {
if !strings.HasPrefix(importPath, m.Path) {
continue
}
pathInModule := importPath[len(m.Path):]
pkgDir := filepath.Join(m.Dir, pathInModule)
if dirIsNestedModule(pkgDir, m) {
continue
}
pkgFiles, err := ioutil.ReadDir(pkgDir)
if err != nil {
continue
}
// A module only contains a package if it has buildable go
// files in that directory. If not, it could be provided by an
// outer module. See #29736.
for _, fi := range pkgFiles {
if ok, _ := r.env.buildContext().MatchFile(pkgDir, fi.Name()); ok {
return m, pkgDir
}
}
}
return nil, ""
}
// findModuleByDir returns the module that contains dir, or nil if no such
// module is in scope.
func (r *moduleResolver) findModuleByDir(dir string) *moduleJSON {
// This is quite tricky and may not be correct. dir could be:
// - a package in the main module.
// - a replace target underneath the main module's directory.
// - a nested module in the above.
// - a replace target somewhere totally random.
// - a nested module in the above.
// - in the mod cache.
// - in /vendor/ in -mod=vendor mode.
// - nested module? Dunno.
// Rumor has it that replace targets cannot contain other replace targets.
for _, m := range r.modsByDir {
if !strings.HasPrefix(dir, m.Dir) {
continue
}
if dirIsNestedModule(dir, m) {
continue
}
return m
}
return nil
}
// dirIsNestedModule reports if dir is contained in a nested module underneath
// mod, not actually in mod.
func dirIsNestedModule(dir string, mod *moduleJSON) bool {
if !strings.HasPrefix(dir, mod.Dir) {
return false
}
mf := findModFile(dir)
if mf == "" {
return false
}
return filepath.Dir(mf) != mod.Dir
}
func findModFile(dir string) string {
for {
f := filepath.Join(dir, "go.mod")
info, err := os.Stat(f)
if err == nil && !info.IsDir() {
return f
}
d := filepath.Dir(dir)
if len(d) >= len(dir) {
return "" // reached top of file system, no go.mod
}
dir = d
}
}
func (r *moduleResolver) loadPackageNames(importPaths []string, srcDir string) (map[string]string, error) {
if err := r.init(); err != nil {
return nil, err
}
names := map[string]string{}
for _, path := range importPaths {
_, packageDir := r.findPackage(path)
if packageDir == "" {
continue
}
name, err := packageDirToName(packageDir)
if err != nil {
continue
}
names[path] = name
}
return names, nil
}
func (r *moduleResolver) scan(_ references) ([]*pkg, error) {
if err := r.init(); err != nil {
return nil, err
}
// Walk GOROOT, GOPATH/pkg/mod, and the main module.
roots := []gopathwalk.Root{
{filepath.Join(r.env.GOROOT, "/src"), gopathwalk.RootGOROOT},
}
if r.main != nil {
roots = append(roots, gopathwalk.Root{r.main.Dir, gopathwalk.RootCurrentModule})
}
for _, p := range filepath.SplitList(r.env.GOPATH) {
roots = append(roots, gopathwalk.Root{filepath.Join(p, "/pkg/mod"), gopathwalk.RootModuleCache})
}
// Walk replace targets, just in case they're not in any of the above.
for _, mod := range r.modsByModPath {
if mod.Replace != nil {
roots = append(roots, gopathwalk.Root{mod.Dir, gopathwalk.RootOther})
}
}
var result []*pkg
dupCheck := make(map[string]bool)
var mu sync.Mutex
gopathwalk.Walk(roots, func(root gopathwalk.Root, dir string) {
mu.Lock()
defer mu.Unlock()
if _, dup := dupCheck[dir]; dup {
return
}
dupCheck[dir] = true
subdir := ""
if dir != root.Path {
subdir = dir[len(root.Path)+len("/"):]
}
importPath := filepath.ToSlash(subdir)
if strings.HasPrefix(importPath, "vendor/") {
// Ignore vendor dirs. If -mod=vendor is on, then things
// should mostly just work, but when it's not vendor/
// is a mess. There's no easy way to tell if it's on.
// We can still find things in the mod cache and
// map them into /vendor when -mod=vendor is on.
return
}
switch root.Type {
case gopathwalk.RootCurrentModule:
importPath = path.Join(r.main.Path, filepath.ToSlash(subdir))
case gopathwalk.RootModuleCache:
matches := modCacheRegexp.FindStringSubmatch(subdir)
modPath, err := module.DecodePath(filepath.ToSlash(matches[1]))
if err != nil {
if Debug {
log.Printf("decoding module cache path %q: %v", subdir, err)
}
return
}
importPath = path.Join(modPath, filepath.ToSlash(matches[3]))
case gopathwalk.RootGOROOT:
importPath = subdir
}
// Check if the directory is underneath a module that's in scope.
if mod := r.findModuleByDir(dir); mod != nil {
// It is. If dir is the target of a replace directive,
// our guessed import path is wrong. Use the real one.
if mod.Dir == dir {
importPath = mod.Path
} else {
dirInMod := dir[len(mod.Dir)+len("/"):]
importPath = path.Join(mod.Path, filepath.ToSlash(dirInMod))
}
} else {
// The package is in an unknown module. Check that it's
// not obviously impossible to import.
var modFile string
switch root.Type {
case gopathwalk.RootModuleCache:
matches := modCacheRegexp.FindStringSubmatch(subdir)
modFile = filepath.Join(matches[1], "@", matches[2], "go.mod")
default:
modFile = findModFile(dir)
}
modBytes, err := ioutil.ReadFile(modFile)
if err == nil && !strings.HasPrefix(importPath, modulePath(modBytes)) {
// The module's declared path does not match
// its expected path. It probably needs a
// replace directive we don't have.
return
}
}
// We may have discovered a package that has a different version
// in scope already. Canonicalize to that one if possible.
if _, canonicalDir := r.findPackage(importPath); canonicalDir != "" {
dir = canonicalDir
}
result = append(result, &pkg{
importPathShort: VendorlessPath(importPath),
dir: dir,
})
}, gopathwalk.Options{Debug: Debug, ModulesEnabled: true})
return result, nil
}
// modCacheRegexp splits a path in a module cache into module, module version, and package.
var modCacheRegexp = regexp.MustCompile(`(.*)@([^/\\]*)(.*)`)
var (
slashSlash = []byte("//")
moduleStr = []byte("module")
)
// modulePath returns the module path from the gomod file text.
// If it cannot find a module path, it returns an empty string.
// It is tolerant of unrelated problems in the go.mod file.
//
// Copied from cmd/go/internal/modfile.
func modulePath(mod []byte) string {
for len(mod) > 0 {
line := mod
mod = nil
if i := bytes.IndexByte(line, '\n'); i >= 0 {
line, mod = line[:i], line[i+1:]
}
if i := bytes.Index(line, slashSlash); i >= 0 {
line = line[:i]
}
line = bytes.TrimSpace(line)
if !bytes.HasPrefix(line, moduleStr) {
continue
}
line = line[len(moduleStr):]
n := len(line)
line = bytes.TrimSpace(line)
if len(line) == n || len(line) == 0 {
continue
}
if line[0] == '"' || line[0] == '`' {
p, err := strconv.Unquote(string(line))
if err != nil {
return "" // malformed quoted string or multiline module path
}
return p
}
return string(line)
}
return "" // missing module path
}
