Golang Object.Exported方法代码示例

// checkInPackageBlock performs safety checks for renames of
// func/var/const/type objects in the package block.
func (r *renamer) checkInPackageBlock(from types.Object) {
	// Check that there are no references to the name from another
	// package if the renaming would make it unexported.
	if ast.IsExported(from.Name()) && !ast.IsExported(r.to) {
		for pkg, info := range r.packages {
			if pkg == from.Pkg() {
				continue
			}
			if id := someUse(info, from); id != nil &&
				!r.checkExport(id, pkg, from) {
				break
			}
		}
	}

	info := r.packages[from.Pkg()]

	// Check that in the package block, "init" is a function, and never referenced.
	if r.to == "init" {
		kind := objectKind(from)
		if kind == "func" {
			// Reject if intra-package references to it exist.
			for id, obj := range info.Uses {
				if obj == from {
					r.errorf(from.Pos(),
						"renaming this func %q to %q would make it a package initializer",
						from.Name(), r.to)
					r.errorf(id.Pos(), "\tbut references to it exist")
					break
				}
			}
		} else {
			r.errorf(from.Pos(), "you cannot have a %s at package level named %q",
				kind, r.to)
		}
	}

	// Check for conflicts between package block and all file blocks.
	for _, f := range info.Files {
		fileScope := info.Info.Scopes[f]
		b, prev := fileScope.LookupParent(r.to, token.NoPos)
		if b == fileScope {
			r.errorf(from.Pos(), "renaming this %s %q to %q would conflict",
				objectKind(from), from.Name(), r.to)
			r.errorf(prev.Pos(), "\twith this %s",
				objectKind(prev))
			return // since checkInPackageBlock would report redundant errors
		}
	}

	// Check for conflicts in lexical scope.
	if from.Exported() {
		for _, info := range r.packages {
			r.checkInLexicalScope(from, info)
		}
	} else {
		r.checkInLexicalScope(from, info)
	}
}

// checkInPackageBlock performs safety checks for renames of
// func/var/const/type objects in the package block.
func (r *Unexporter) checkInPackageBlock(objsToUpdate map[types.Object]string, from types.Object, to string) {
	// Check that there are no references to the name from another
	// package if the renaming would make it unexported.
	if ast.IsExported(from.Name()) && !ast.IsExported(to) {
		for pkg, info := range r.packages {
			if pkg == from.Pkg() {
				continue
			}
			if id := someUse(info, from); id != nil &&
				!r.checkExport(id, pkg, from, to) {
				break
			}
		}
	}

	info := r.packages[from.Pkg()]
	lexinfo := r.lexInfo(info)

	// Check that in the package block, "init" is a function, and never referenced.
	if to == "init" {
		kind := objectKind(from)
		if kind == "func" {
			// Reject if intra-package references to it exist.
			if refs := lexinfo.Refs[from]; len(refs) > 0 {
				r.warn(from,
					r.errorf(from.Pos(),
						"renaming this func %q to %q would make it a package initializer",
						from.Name(), to),
					r.errorf(refs[0].Id.Pos(), "\tbut references to it exist"))
			}
		} else {
			r.warn(from, r.errorf(from.Pos(), "you cannot have a %s at package level named %q",
				kind, to))
		}
	}

	// Check for conflicts between package block and all file blocks.
	for _, f := range info.Files {
		if prev, b := lexinfo.Blocks[f].Lookup(to); b == lexinfo.Blocks[f] {
			r.warn(from,
				r.errorf(from.Pos(), "renaming this %s %q to %q would conflict",
					objectKind(from), from.Name(), to),
				r.errorf(prev.Pos(), "\twith this %s",
					objectKind(prev)))
			return // since checkInPackageBlock would report redundant errors
		}
	}

	// Check for conflicts in lexical scope.
	if from.Exported() {
		for _, info := range r.packages {
			r.checkInLexicalScope(objsToUpdate, from, to, info)
		}
	} else {
		r.checkInLexicalScope(objsToUpdate, from, to, info)
	}
}

func (c *funcContext) objectName(o types.Object) string {
	if isPkgLevel(o) {
		c.p.dependencies[o] = true

		if o.Pkg() != c.p.Pkg || (isVarOrConst(o) && o.Exported()) {
			return c.pkgVar(o.Pkg()) + "." + o.Name()
		}
	}

	name, ok := c.p.objectNames[o]
	if !ok {
		name = c.newVariableWithLevel(o.Name(), isPkgLevel(o))
		c.p.objectNames[o] = name
	}

	if v, ok := o.(*types.Var); ok && c.p.escapingVars[v] {
		return name + "[0]"
	}
	return name
}

func isExported(obj types.Object) bool {
	// https://golang.org/ref/spec#Exported_identifiers
	// An identifier is exported if both:
	// the first character of the identifier's name is a Unicode upper case letter (Unicode class "Lu"); and
	// the identifier is declared in the package block or it is a field name or method name.
	// All other identifiers are not exported.

	if !obj.Exported() {
		// does not start with an upper case letter
		return false
	}

	if v, ok := obj.(*types.Var); ok && v.IsField() {
		// is a field name
		return true
	}
	if sig, ok := obj.Type().(*types.Signature); ok && sig.Recv() != nil {
		// is a method name
		return true
	}
	// is declared in the package block
	return obj.Parent() == obj.Pkg().Scope()
}

// Referrers reports all identifiers that resolve to the same object
// as the queried identifier, within any package in the analysis scope.
func referrers(q *Query) error {
	lconf := loader.Config{Build: q.Build}
	allowErrors(&lconf)

	if _, err := importQueryPackage(q.Pos, &lconf); err != nil {
		return err
	}

	var id *ast.Ident
	var obj types.Object
	var lprog *loader.Program
	var pass2 bool
	var qpos *queryPos
	for {
		// Load/parse/type-check the program.
		var err error
		lprog, err = lconf.Load()
		if err != nil {
			return err
		}
		q.Fset = lprog.Fset

		qpos, err = parseQueryPos(lprog, q.Pos, false)
		if err != nil {
			return err
		}

		id, _ = qpos.path[0].(*ast.Ident)
		if id == nil {
			return fmt.Errorf("no identifier here")
		}

		obj = qpos.info.ObjectOf(id)
		if obj == nil {
			// Happens for y in "switch y := x.(type)",
			// the package declaration,
			// and unresolved identifiers.
			if _, ok := qpos.path[1].(*ast.File); ok { // package decl?
				pkg := qpos.info.Pkg
				obj = types.NewPkgName(id.Pos(), pkg, pkg.Name(), pkg)
			} else {
				return fmt.Errorf("no object for identifier: %T", qpos.path[1])
			}
		}

		if pass2 {
			break
		}

		// If the identifier is exported, we must load all packages that
		// depend transitively upon the package that defines it.
		// Treat PkgNames as exported, even though they're lowercase.
		if _, isPkg := obj.(*types.PkgName); !(isPkg || obj.Exported()) {
			break // not exported
		}

		// Scan the workspace and build the import graph.
		// Ignore broken packages.
		_, rev, _ := importgraph.Build(q.Build)

		// Re-load the larger program.
		// Create a new file set so that ...
		// External test packages are never imported,
		// so they will never appear in the graph.
		// (We must reset the Config here, not just reset the Fset field.)
		lconf = loader.Config{
			Fset:  token.NewFileSet(),
			Build: q.Build,
		}
		allowErrors(&lconf)
		for path := range rev.Search(obj.Pkg().Path()) {
			lconf.ImportWithTests(path)
		}
		pass2 = true
	}

	// Iterate over all go/types' Uses facts for the entire program.
	var refs []*ast.Ident
	for _, info := range lprog.AllPackages {
		for id2, obj2 := range info.Uses {
			if sameObj(obj, obj2) {
				refs = append(refs, id2)
			}
		}
	}
	sort.Sort(byNamePos{q.Fset, refs})

	q.result = &referrersResult{
		qpos:  qpos,
		query: id,
		obj:   obj,
		refs:  refs,
	}
	return nil
}