1 files changed, 355 insertions, 0 deletions
diff --git a/vendor/golang.org/x/tools/imports/mod.go b/vendor/golang.org/x/tools/imports/mod.go
new file mode 100644
index 00000000..018c43ce
--- /dev/null
+++ b/vendor/golang.org/x/tools/imports/mod.go
@@ -0,0 +1,355 @@
+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
+}