Golang loader.Config類代碼示例

// Parse parses the ast for this file and returns a ParsedFile
func (w *Weave) ParseAST(fname string) *ast.File {
	var err error

	fset := token.NewFileSet()
	af, err := parser.ParseFile(fset, fname, nil, 0)
	if err != nil {
		w.flog.Println(err)
	}

	loadcfg := loader.Config{}
	loadcfg.CreateFromFilenames(fname)

	info := types.Info{
		Types: make(map[ast.Expr]types.TypeAndValue),
		Defs:  make(map[*ast.Ident]types.Object),
	}

	var conf types.Config
	_, err = conf.Check(af.Name.Name, fset, []*ast.File{af}, &info)
	if err != nil {
		if w.warnAST {
			w.flog.Println(err)
		}
	}

	return af
}

// loadWithSoftErrors calls lconf.Load, suppressing "soft" errors.  (See Go issue 16530.)
// TODO(adonovan): Once the loader has an option to allow soft errors,
// replace calls to loadWithSoftErrors with loader calls with that parameter.
func loadWithSoftErrors(lconf *loader.Config) (*loader.Program, error) {
	lconf.AllowErrors = true

	// Ideally we would just return conf.Load() here, but go/types
	// reports certain "soft" errors that gc does not (Go issue 14596).
	// As a workaround, we set AllowErrors=true and then duplicate
	// the loader's error checking but allow soft errors.
	// It would be nice if the loader API permitted "AllowErrors: soft".
	prog, err := lconf.Load()
	if err != nil {
		return nil, err
	}
	var errpkgs []string
	// Report hard errors in indirectly imported packages.
	for _, info := range prog.AllPackages {
		if containsHardErrors(info.Errors) {
			errpkgs = append(errpkgs, info.Pkg.Path())
		} else {
			// Enable SSA construction for packages containing only soft errors.
			info.TransitivelyErrorFree = true
		}
	}
	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)
	}
	return prog, err
}

func TestCwd(t *testing.T) {
	ctxt := fakeContext(map[string]string{"one/two/three": `package three`})
	for _, test := range []struct {
		cwd, arg, want string
	}{
		{cwd: "/go/src/one", arg: "./two/three", want: "one/two/three"},
		{cwd: "/go/src/one", arg: "../one/two/three", want: "one/two/three"},
		{cwd: "/go/src/one", arg: "one/two/three", want: "one/two/three"},
		{cwd: "/go/src/one/two/three", arg: ".", want: "one/two/three"},
		{cwd: "/go/src/one", arg: "two/three", want: ""},
	} {
		conf := loader.Config{
			Cwd:   test.cwd,
			Build: ctxt,
		}
		conf.Import(test.arg)

		var got string
		prog, err := conf.Load()
		if prog != nil {
			got = imported(prog)
		}
		if got != test.want {
			t.Errorf("Load(%s) from %s: Imported = %s, want %s",
				test.arg, test.cwd, got, test.want)
			if err != nil {
				t.Errorf("Load failed: %v", err)
			}
		}
	}
}

func loadProgram(args []string, tests bool) (*ssa.Program, error) {
	conf := loader.Config{}

	if len(args) == 0 {
		fmt.Fprintln(os.Stderr, Usage)
		os.Exit(1)
	}

	// Use the initial packages from the command line.
	args, err := conf.FromArgs(args, tests)
	if err != nil {
		return nil, err
	}

	// Load, parse and type-check the whole program.
	iprog, err := conf.Load()
	if err != nil {
		return nil, err
	}

	// Create and build SSA-form program representation.
	prog := ssautil.CreateProgram(iprog, 0)
	prog.BuildAll()
	return prog, nil
}

func TestStdlib(t *testing.T) {
	defer func(saved func(format string, args ...interface{})) {
		logf = saved
	}(logf)
	logf = t.Errorf

	ctxt := build.Default // copy

	// Enumerate $GOROOT packages.
	saved := ctxt.GOPATH
	ctxt.GOPATH = "" // disable GOPATH during AllPackages
	pkgs := buildutil.AllPackages(&ctxt)
	ctxt.GOPATH = saved

	// Throw in a number of go.tools packages too.
	pkgs = append(pkgs,
		"golang.org/x/tools/cmd/godoc",
		"golang.org/x/tools/refactor/lexical")

	// Load, parse and type-check the program.
	conf := loader.Config{Build: &ctxt}
	for _, path := range pkgs {
		conf.ImportWithTests(path)
	}
	iprog, err := conf.Load()
	if err != nil {
		t.Fatalf("Load failed: %v", err)
	}

	// This test ensures that Structure doesn't panic and that
	// its internal sanity-checks against go/types don't fail.
	for pkg, info := range iprog.AllPackages {
		_ = Structure(iprog.Fset, pkg, &info.Info, info.Files)
	}
}

// Create unexporter
func NewUnexporter(o *Config) (*unexporter, error) {

	var conf loader.Config
	for _, package_name := range buildutil.AllPackages(&build.Default) {
		conf.ImportWithTests(package_name)
	}
	program, err := conf.Load()
	if err != nil {
		return nil, err
	}

	if program.Package(o.Pkg) == nil {
		return nil, errors.New(fmt.Sprintf("'%s' is not a valid package", o.Pkg))
	}

	if o.Debug {
		pkg := program.Package(o.Pkg).Pkg
		fmt.Printf("finding unused identifiers for %s (%s)\n", pkg.Name(), pkg.Path())
	}

	unexporter := &unexporter{
		Program:     program,
		MainPackage: program.Package(o.Pkg),
		Verbose:     o.Debug,
	}

	unexporter.run()

	return unexporter, nil

}

// Return count of unused vars
func myloader(args []string) (count int) {
	var conf loader.Config
	conf.FromArgs(args, false)
	prog, err := conf.Load()
	if err != nil {
		log.Fatal(err)
	}

	for _, pi := range prog.Created {
		fmt.Println(pi)
	}

	info := prog.Package(args[0]).Info
	fset := prog.Fset

	ssaprog := ssautil.CreateProgram(prog, ssa.GlobalDebug)
	ssaprog.Build()

	for expr, object := range info.Defs {
		unused := checkObj(expr, object, prog, ssaprog, fset)
		if unused {
			fmt.Fprintf(os.Stderr, "Unused assignment for '%v' %v\n", expr, fset.Position(expr.Pos()))
			count++
		}
	}
	for expr, object := range info.Uses {
		unused := checkObj(expr, object, prog, ssaprog, fset)
		if unused {
			fmt.Fprintf(os.Stderr, "Unused assignment for '%v' %v\n", expr, fset.Position(expr.Pos()))
			count++
		}
	}
	return count
}

func TestTransitivelyErrorFreeFlag(t *testing.T) {
	// Create an minimal custom build.Context
	// that fakes the following packages:
	//
	// a --> b --> c!   c has an error
	//   \              d and e are transitively error-free.
	//    e --> d
	//
	// Each package [a-e] consists of one file, x.go.
	pkgs := map[string]string{
		"a": `package a; import (_ "b"; _ "e")`,
		"b": `package b; import _ "c"`,
		"c": `package c; func f() { _ = int(false) }`, // type error within function body
		"d": `package d;`,
		"e": `package e; import _ "d"`,
	}
	conf := loader.Config{
		AllowErrors:   true,
		SourceImports: true,
		Build:         fakeContext(pkgs),
	}
	conf.Import("a")

	prog, err := conf.Load()
	if err != nil {
		t.Errorf("Load failed: %s", err)
	}
	if prog == nil {
		t.Fatalf("Load returned nil *Program")
	}

	for pkg, info := range prog.AllPackages {
		var wantErr, wantTEF bool
		switch pkg.Path() {
		case "a", "b":
		case "c":
			wantErr = true
		case "d", "e":
			wantTEF = true
		default:
			t.Errorf("unexpected package: %q", pkg.Path())
			continue
		}

		if (info.Errors != nil) != wantErr {
			if wantErr {
				t.Errorf("Package %q.Error = nil, want error", pkg.Path())
			} else {
				t.Errorf("Package %q has unexpected Errors: %v",
					pkg.Path(), info.Errors)
			}
		}

		if info.TransitivelyErrorFree != wantTEF {
			t.Errorf("Package %q.TransitivelyErrorFree=%t, want %t",
				pkg.Path(), info.TransitivelyErrorFree, wantTEF)
		}
	}
}

// createProgram returns a program containing packages specified.
func createProgram(packages ...string) (*loader.Program, error) {
	var conf loader.Config

	for _, name := range packages {
		conf.CreateFromFilenames(name, getFileNames(name)...)
	}
	return conf.Load()
}

// Query runs a single oracle query.
//
// args specify the main package in (*loader.Config).FromArgs syntax.
// mode is the query mode ("callers", etc).
// ptalog is the (optional) pointer-analysis log file.
// buildContext is the go/build configuration for locating packages.
// reflection determines whether to model reflection soundly (currently slow).
//
// Clients that intend to perform multiple queries against the same
// analysis scope should use this pattern instead:
//
//	conf := loader.Config{Build: buildContext, SourceImports: true}
//	... populate config, e.g. conf.FromArgs(args) ...
//	iprog, err := conf.Load()
//	if err != nil { ... }
// 	o, err := oracle.New(iprog, nil, false)
//	if err != nil { ... }
//	for ... {
//		qpos, err := oracle.ParseQueryPos(imp, pos, needExact)
//		if err != nil { ... }
//
//		res, err := o.Query(mode, qpos)
//		if err != nil { ... }
//
//		// use res
//	}
//
// TODO(adonovan): the ideal 'needsExact' parameter for ParseQueryPos
// depends on the query mode; how should we expose this?
//
func Query(args []string, mode, pos string, ptalog io.Writer, buildContext *build.Context, reflection bool) (*Result, error) {
	if mode == "what" {
		// Bypass package loading, type checking, SSA construction.
		return what(pos, buildContext)
	}

	minfo := findMode(mode)
	if minfo == nil {
		return nil, fmt.Errorf("invalid mode type: %q", mode)
	}

	conf := loader.Config{Build: buildContext, SourceImports: true}

	// Determine initial packages.
	args, err := conf.FromArgs(args, true)
	if err != nil {
		return nil, err
	}
	if len(args) > 0 {
		return nil, fmt.Errorf("surplus arguments: %q", args)
	}

	// For queries needing only a single typed package,
	// reduce the analysis scope to that package.
	if minfo.needs&(needSSA|needRetainTypeInfo) == 0 {
		reduceScope(pos, &conf)
	}

	// TODO(adonovan): report type errors to the user via Serial
	// types, not stderr?
	// conf.TypeChecker.Error = func(err error) {
	// 	E := err.(types.Error)
	// 	fmt.Fprintf(os.Stderr, "%s: %s\n", E.Fset.Position(E.Pos), E.Msg)
	// }

	// Load/parse/type-check the program.
	iprog, err := conf.Load()
	if err != nil {
		return nil, err
	}

	o, err := newOracle(iprog, ptalog, minfo.needs, reflection)
	if err != nil {
		return nil, err
	}

	qpos, err := ParseQueryPos(iprog, pos, minfo.needs&needExactPos != 0)
	if err != nil && minfo.needs&(needPos|needExactPos) != 0 {
		return nil, err
	}

	// SSA is built and we have the QueryPos.
	// Release the other ASTs and type info to the GC.
	iprog = nil

	return o.query(minfo, qpos)
}

func TestLoad_BadDependency_AllowErrors(t *testing.T) {
	for _, test := range []struct {
		descr    string
		pkgs     map[string]string
		wantPkgs string
	}{

		{
			descr: "missing dependency",
			pkgs: map[string]string{
				"a": `package a; import _ "b"`,
				"b": `package b; import _ "c"`,
			},
			wantPkgs: "a b",
		},
		{
			descr: "bad package decl in dependency",
			pkgs: map[string]string{
				"a": `package a; import _ "b"`,
				"b": `package b; import _ "c"`,
				"c": `package`,
			},
			wantPkgs: "a b",
		},
		{
			descr: "parse error in dependency",
			pkgs: map[string]string{
				"a": `package a; import _ "b"`,
				"b": `package b; import _ "c"`,
				"c": `package c; var x = `,
			},
			wantPkgs: "a b c",
		},
	} {
		conf := loader.Config{
			AllowErrors:   true,
			SourceImports: true,
			Build:         fakeContext(test.pkgs),
		}
		conf.Import("a")

		prog, err := conf.Load()
		if err != nil {
			t.Errorf("%s: Load failed unexpectedly: %v", test.descr, err)
		}
		if prog == nil {
			t.Fatalf("%s: Load returned a nil Program", test.descr)
		}

		if got, want := imported(prog), "a"; got != want {
			t.Errorf("%s: Imported = %s, want %s", test.descr, got, want)
		}
		if got := all(prog); strings.Join(got, " ") != test.wantPkgs {
			t.Errorf("%s: AllPackages = %s, want %s", test.descr, got, test.wantPkgs)
		}
	}
}

// allowErrors causes type errors to be silently ignored.
// (Not suitable if SSA construction follows.)
func allowErrors(lconf *loader.Config) {
	ctxt := *lconf.Build // copy
	ctxt.CgoEnabled = false
	lconf.Build = &ctxt
	lconf.AllowErrors = true
	// AllErrors makes the parser always return an AST instead of
	// bailing out after 10 errors and returning an empty ast.File.
	lconf.ParserMode = parser.AllErrors
	lconf.TypeChecker.Error = func(err error) {}
}

// Test that both syntax (scan/parse) and type errors are both recorded
// (in PackageInfo.Errors) and reported (via Config.TypeChecker.Error).
func TestErrorReporting(t *testing.T) {
	pkgs := map[string]string{
		"a": `package a; import _ "b"; var x int = false`,
		"b": `package b; 'syntax error!`,
	}
	conf := loader.Config{
		AllowErrors:   true,
		SourceImports: true,
		Build:         fakeContext(pkgs),
	}
	var allErrors []error
	conf.TypeChecker.Error = func(err error) {
		allErrors = append(allErrors, err)
	}
	conf.Import("a")

	prog, err := conf.Load()
	if err != nil {
		t.Errorf("Load failed: %s", err)
	}
	if prog == nil {
		t.Fatalf("Load returned nil *Program")
	}

	hasError := func(errors []error, substr string) bool {
		for _, err := range errors {
			if strings.Contains(err.Error(), substr) {
				return true
			}
		}
		return false
	}

	// TODO(adonovan): test keys of ImportMap.

	// Check errors recorded in each PackageInfo.
	for pkg, info := range prog.AllPackages {
		switch pkg.Path() {
		case "a":
			if !hasError(info.Errors, "cannot convert false") {
				t.Errorf("a.Errors = %v, want bool conversion (type) error", info.Errors)
			}
		case "b":
			if !hasError(info.Errors, "rune literal not terminated") {
				t.Errorf("b.Errors = %v, want unterminated literal (syntax) error", info.Errors)
			}
		}
	}

	// Check errors reported via error handler.
	if !hasError(allErrors, "cannot convert false") ||
		!hasError(allErrors, "rune literal not terminated") {
		t.Errorf("allErrors = %v, want both syntax and type errors", allErrors)
	}
}

// This example imports three packages, including the tests for one of
// them, and loads all their dependencies.
func ExampleConfig_Import() {
	// ImportWithTest("strconv") causes strconv to include
	// internal_test.go, and creates an external test package,
	// strconv_test.
	// (Compare with the example of CreateFromFiles.)

	var conf loader.Config
	conf.Import("unicode/utf8")
	conf.Import("errors")
	conf.ImportWithTests("strconv")
	prog, err := conf.Load()
	if err != nil {
		log.Fatal(err)
	}

	printProgram(prog)
	printFilenames(prog.Fset, prog.Package("strconv"))
	printFilenames(prog.Fset, prog.Package("strconv_test"))
	// Output:
	// created: [strconv_test]
	// imported: [errors strconv unicode/utf8]
	// initial: [errors strconv strconv_test unicode/utf8]
	// all: [bufio bytes errors flag fmt io log math math/rand os reflect runtime runtime/pprof runtime/trace sort strconv strconv_test strings sync sync/atomic syscall testing text/tabwriter time unicode unicode/utf8]
	// strconv.Files: [atob.go atof.go atoi.go decimal.go doc.go extfloat.go ftoa.go isprint.go itoa.go quote.go internal_test.go]
	// strconv_test.Files: [atob_test.go atof_test.go atoi_test.go decimal_test.go example_test.go fp_test.go ftoa_test.go itoa_test.go quote_test.go strconv_test.go]
}

func main() {
	// Loader is a tool for opening Go files, it loads from a Config type
	conf := loader.Config{
		Build: &build.Default,
	}

	path, _ := filepath.Abs("looper")
	file, err := conf.ParseFile(path+"/"+"looper.go", nil)
	if err != nil {
		fmt.Println(err)
		return
	}

	// Creation of a single file main pacakge
	conf.CreateFromFiles("looper", file)
	conf.Import("runtime")

	p, err := conf.Load()
	if err != nil {
		fmt.Println(err)
		return
	}

	// Finally, create SSA representation from the package we've loaded
	program := ssautil.CreateProgram(p, ssa.SanityCheckFunctions)
	looperPkg := program.Package(p.Created[0].Pkg)

	fmt.Println("RIGHT IN THE SINGLE STATIC ASSIGNMENT FORM:")
	looperPkg.WriteTo(os.Stdout)

	fmt.Println("LOOK AT THIS HERE LOOPER FUNC:")
	looperFunc := looperPkg.Func("Looper")
	looperFunc.WriteTo(os.Stdout)
}