Golang token.FileSet类代码示例

// Imports returns the file imports grouped by paragraph.
func Imports(fset *token.FileSet, f *ast.File) [][]*ast.ImportSpec {
	var groups [][]*ast.ImportSpec

	for _, decl := range f.Decls {
		genDecl, ok := decl.(*ast.GenDecl)
		if !ok || genDecl.Tok != token.IMPORT {
			break
		}

		group := []*ast.ImportSpec{}

		var lastLine int
		for _, spec := range genDecl.Specs {
			importSpec := spec.(*ast.ImportSpec)
			pos := importSpec.Path.ValuePos
			line := fset.Position(pos).Line
			if lastLine > 0 && pos > 0 && line-lastLine > 1 {
				groups = append(groups, group)
				group = []*ast.ImportSpec{}
			}
			group = append(group, importSpec)
			lastLine = line
		}
		groups = append(groups, group)
	}

	return groups
}

// compareErrors compares the map of expected error messages with the list
// of found errors and reports discrepancies.
//
func compareErrors(t *testing.T, fset *token.FileSet, expected map[token.Pos]string, found scanner.ErrorList) {
	for _, error := range found {
		// error.Pos is a token.Position, but we want
		// a token.Pos so we can do a map lookup
		pos := getPos(fset, error.Pos.Filename, error.Pos.Offset)
		if msg, found := expected[pos]; found {
			// we expect a message at pos; check if it matches
			rx, err := regexp.Compile(msg)
			if err != nil {
				t.Errorf("%s: %v", error.Pos, err)
				continue
			}
			if match := rx.MatchString(error.Msg); !match {
				t.Errorf("%s: %q does not match %q", error.Pos, error.Msg, msg)
				continue
			}
			// we have a match - eliminate this error
			delete(expected, pos)
		} else {
			// To keep in mind when analyzing failed test output:
			// If the same error position occurs multiple times in errors,
			// this message will be triggered (because the first error at
			// the position removes this position from the expected errors).
			t.Errorf("%s: unexpected error: %s", error.Pos, error.Msg)
		}
	}

	// there should be no expected errors left
	if len(expected) > 0 {
		t.Errorf("%d errors not reported:", len(expected))
		for pos, msg := range expected {
			t.Errorf("%s: %s\n", fset.Position(pos), msg)
		}
	}
}

func convertAST(info *types.Info, src []byte, sgoAST *ast.File, fset *token.FileSet) []byte {
	c := converter{
		Info: info,
		src:  src,
		base: fset.File(sgoAST.Pos()).Base() - 1,
		fset: fset,
	}
	c.convertFile(sgoAST)
	return bytes.Join(append(c.dstChunks, src[c.lastChunkEnd:]), nil)
}

// getFile assumes that each filename occurs at most once
func getFile(fset *token.FileSet, filename string) (file *token.File) {
	fset.Iterate(func(f *token.File) bool {
		if f.Name() == filename {
			if file != nil {
				panic(filename + " used multiple times")
			}
			file = f
		}
		return true
	})
	return file
}

// Eval returns the type and, if constant, the value for the
// expression expr, evaluated at position pos of package pkg,
// which must have been derived from type-checking an AST with
// complete position information relative to the provided file
// set.
//
// If the expression contains function literals, their bodies
// are ignored (i.e., the bodies are not type-checked).
//
// If pkg == nil, the Universe scope is used and the provided
// position pos is ignored. If pkg != nil, and pos is invalid,
// the package scope is used. Otherwise, pos must belong to the
// package.
//
// An error is returned if pos is not within the package or
// if the node cannot be evaluated.
//
// Note: Eval should not be used instead of running Check to compute
// types and values, but in addition to Check. Eval will re-evaluate
// its argument each time, and it also does not know about the context
// in which an expression is used (e.g., an assignment). Thus, top-
// level untyped constants will return an untyped type rather then the
// respective context-specific type.
//
func Eval(fset *token.FileSet, pkg *Package, pos token.Pos, expr string) (TypeAndValue, error) {
	// determine scope
	var scope *Scope
	if pkg == nil {
		scope = Universe
		pos = token.NoPos
	} else if !pos.IsValid() {
		scope = pkg.scope
	} else {
		// The package scope extent (position information) may be
		// incorrect (files spread across a wide range of fset
		// positions) - ignore it and just consider its children
		// (file scopes).
		for _, fscope := range pkg.scope.children {
			if scope = fscope.Innermost(pos); scope != nil {
				break
			}
		}
		if scope == nil || debug {
			s := scope
			for s != nil && s != pkg.scope {
				s = s.parent
			}
			// s == nil || s == pkg.scope
			if s == nil {
				return TypeAndValue{}, fmt.Errorf("no position %s found in package %s", fset.Position(pos), pkg.name)
			}
		}
	}

	// parse expressions
	node, err := parser.ParseExprFrom(fset, "eval", expr, 0)
	if err != nil {
		return TypeAndValue{}, err
	}

	// initialize checker
	check := NewChecker(nil, fset, pkg, nil)
	check.scope = scope
	check.pos = pos
	defer check.handleBailout(&err)

	// evaluate node
	var x operand
	check.rawExpr(&x, node, nil)
	return TypeAndValue{x.mode, x.typ, x.val}, err
}

// findInterval parses input and returns the [start, end) positions of
// the first occurrence of substr in input.  f==nil indicates failure;
// an error has already been reported in that case.
//
func findInterval(t *testing.T, fset *token.FileSet, input, substr string) (f *ast.File, start, end token.Pos) {
	f, err := parser.ParseFile(fset, "<input>", input, 0)
	if err != nil {
		t.Errorf("parse error: %s", err)
		return
	}

	i := strings.Index(input, substr)
	if i < 0 {
		t.Errorf("%q is not a substring of input", substr)
		f = nil
		return
	}

	filePos := fset.File(f.Package)
	return f, filePos.Pos(i), filePos.Pos(i + len(substr))
}

func makeErrList(fset *token.FileSet, errs []error) scanner.ErrorList {
	var errList scanner.ErrorList
	for _, err := range errs {
		if v, ok := err.(*types.Error); ok {
			errList = append(errList, &scanner.Error{
				Pos: fset.Position(v.Pos),
				Msg: v.Msg,
			})
		} else {
			errList = append(errList, &scanner.Error{
				Pos: token.Position{},
				Msg: err.Error(),
			})
		}
	}
	return errList
}

// sortImports sorts runs of consecutive import lines in import blocks in f.
// It also removes duplicate imports when it is possible to do so without data loss.
func sortImports(fset *token.FileSet, f *ast.File) {
	for i, d := range f.Decls {
		d, ok := d.(*ast.GenDecl)
		if !ok || d.Tok != token.IMPORT {
			// Not an import declaration, so we're done.
			// Imports are always first.
			break
		}

		if len(d.Specs) == 0 {
			// Empty import block, remove it.
			f.Decls = append(f.Decls[:i], f.Decls[i+1:]...)
		}

		if !d.Lparen.IsValid() {
			// Not a block: sorted by default.
			continue
		}

		// Identify and sort runs of specs on successive lines.
		i := 0
		specs := d.Specs[:0]
		for j, s := range d.Specs {
			if j > i && fset.Position(s.Pos()).Line > 1+fset.Position(d.Specs[j-1].End()).Line {
				// j begins a new run.  End this one.
				specs = append(specs, sortSpecs(fset, f, d.Specs[i:j])...)
				i = j
			}
		}
		specs = append(specs, sortSpecs(fset, f, d.Specs[i:])...)
		d.Specs = specs

		// Deduping can leave a blank line before the rparen; clean that up.
		if len(d.Specs) > 0 {
			lastSpec := d.Specs[len(d.Specs)-1]
			lastLine := fset.Position(lastSpec.Pos()).Line
			if rParenLine := fset.Position(d.Rparen).Line; rParenLine > lastLine+1 {
				fset.File(d.Rparen).MergeLine(rParenLine - 1)
			}
		}
	}
}

// NewCommentMap creates a new comment map by associating comment groups
// of the comments list with the nodes of the AST specified by node.
//
// A comment group g is associated with a node n if:
//
//   - g starts on the same line as n ends
//   - g starts on the line immediately following n, and there is
//     at least one empty line after g and before the next node
//   - g starts before n and is not associated to the node before n
//     via the previous rules
//
// NewCommentMap tries to associate a comment group to the "largest"
// node possible: For instance, if the comment is a line comment
// trailing an assignment, the comment is associated with the entire
// assignment rather than just the last operand in the assignment.
//
func NewCommentMap(fset *token.FileSet, node Node, comments []*CommentGroup) CommentMap {
	if len(comments) == 0 {
		return nil // no comments to map
	}

	cmap := make(CommentMap)

	// set up comment reader r
	tmp := make([]*CommentGroup, len(comments))
	copy(tmp, comments) // don't change incoming comments
	sortComments(tmp)
	r := commentListReader{fset: fset, list: tmp} // !r.eol() because len(comments) > 0
	r.next()

	// create node list in lexical order
	nodes := nodeList(node)
	nodes = append(nodes, nil) // append sentinel

	// set up iteration variables
	var (
		p     Node           // previous node
		pend  token.Position // end of p
		pg    Node           // previous node group (enclosing nodes of "importance")
		pgend token.Position // end of pg
		stack nodeStack      // stack of node groups
	)

	for _, q := range nodes {
		var qpos token.Position
		if q != nil {
			qpos = fset.Position(q.Pos()) // current node position
		} else {
			// set fake sentinel position to infinity so that
			// all comments get processed before the sentinel
			const infinity = 1 << 30
			qpos.Offset = infinity
			qpos.Line = infinity
		}

		// process comments before current node
		for r.end.Offset <= qpos.Offset {
			// determine recent node group
			if top := stack.pop(r.comment.Pos()); top != nil {
				pg = top
				pgend = fset.Position(pg.End())
			}
			// Try to associate a comment first with a node group
			// (i.e., a node of "importance" such as a declaration);
			// if that fails, try to associate it with the most recent
			// node.
			// TODO(gri) try to simplify the logic below
			var assoc Node
			switch {
			case pg != nil &&
				(pgend.Line == r.pos.Line ||
					pgend.Line+1 == r.pos.Line && r.end.Line+1 < qpos.Line):
				// 1) comment starts on same line as previous node group ends, or
				// 2) comment starts on the line immediately after the
				//    previous node group and there is an empty line before
				//    the current node
				// => associate comment with previous node group
				assoc = pg
			case p != nil &&
				(pend.Line == r.pos.Line ||
					pend.Line+1 == r.pos.Line && r.end.Line+1 < qpos.Line ||
					q == nil):
				// same rules apply as above for p rather than pg,
				// but also associate with p if we are at the end (q == nil)
				assoc = p
			default:
				// otherwise, associate comment with current node
				if q == nil {
					// we can only reach here if there was no p
					// which would imply that there were no nodes
					panic("internal error: no comments should be associated with sentinel")
				}
				assoc = q
			}
			cmap.addComment(assoc, r.comment)
			if r.eol() {
				return cmap
			}
			r.next()
		}
//.........这里部分代码省略.........

func sortSpecs(fset *token.FileSet, f *ast.File, specs []ast.Spec) []ast.Spec {
	// Can't short-circuit here even if specs are already sorted,
	// since they might yet need deduplication.
	// A lone import, however, may be safely ignored.
	if len(specs) <= 1 {
		return specs
	}

	// Record positions for specs.
	pos := make([]posSpan, len(specs))
	for i, s := range specs {
		pos[i] = posSpan{s.Pos(), s.End()}
	}

	// Identify comments in this range.
	// Any comment from pos[0].Start to the final line counts.
	lastLine := fset.Position(pos[len(pos)-1].End).Line
	cstart := len(f.Comments)
	cend := len(f.Comments)
	for i, g := range f.Comments {
		if g.Pos() < pos[0].Start {
			continue
		}
		if i < cstart {
			cstart = i
		}
		if fset.Position(g.End()).Line > lastLine {
			cend = i
			break
		}
	}
	comments := f.Comments[cstart:cend]

	// Assign each comment to the import spec preceding it.
	importComment := map[*ast.ImportSpec][]*ast.CommentGroup{}
	specIndex := 0
	for _, g := range comments {
		for specIndex+1 < len(specs) && pos[specIndex+1].Start <= g.Pos() {
			specIndex++
		}
		s := specs[specIndex].(*ast.ImportSpec)
		importComment[s] = append(importComment[s], g)
	}

	// Sort the import specs by import path.
	// Remove duplicates, when possible without data loss.
	// Reassign the import paths to have the same position sequence.
	// Reassign each comment to abut the end of its spec.
	// Sort the comments by new position.
	sort.Sort(byImportSpec(specs))

	// Dedup. Thanks to our sorting, we can just consider
	// adjacent pairs of imports.
	deduped := specs[:0]
	for i, s := range specs {
		if i == len(specs)-1 || !collapse(s, specs[i+1]) {
			deduped = append(deduped, s)
		} else {
			p := s.Pos()
			fset.File(p).MergeLine(fset.Position(p).Line)
		}
	}
	specs = deduped

	// Fix up comment positions
	for i, s := range specs {
		s := s.(*ast.ImportSpec)
		if s.Name != nil {
			s.Name.NamePos = pos[i].Start
		}
		s.Path.ValuePos = pos[i].Start
		s.EndPos = pos[i].End
		for _, g := range importComment[s] {
			for _, c := range g.List {
				c.Slash = pos[i].End
			}
		}
	}

	sort.Sort(byCommentPos(comments))

	return specs
}

// AddNamedImport adds the import path to the file f, if absent.
// If name is not empty, it is used to rename the import.
//
// For example, calling
//	AddNamedImport(fset, f, "pathpkg", "path")
// adds
//	import pathpkg "path"
func AddNamedImport(fset *token.FileSet, f *ast.File, name, ipath string) (added bool) {
	if imports(f, ipath) {
		return false
	}

	newImport := &ast.ImportSpec{
		Path: &ast.BasicLit{
			Kind:  token.STRING,
			Value: strconv.Quote(ipath),
		},
	}
	if name != "" {
		newImport.Name = &ast.Ident{Name: name}
	}

	// Find an import decl to add to.
	// The goal is to find an existing import
	// whose import path has the longest shared
	// prefix with ipath.
	var (
		bestMatch  = -1         // length of longest shared prefix
		lastImport = -1         // index in f.Decls of the file's final import decl
		impDecl    *ast.GenDecl // import decl containing the best match
		impIndex   = -1         // spec index in impDecl containing the best match
	)
	for i, decl := range f.Decls {
		gen, ok := decl.(*ast.GenDecl)
		if ok && gen.Tok == token.IMPORT {
			lastImport = i
			// Do not add to import "C", to avoid disrupting the
			// association with its doc comment, breaking cgo.
			if declImports(gen, "C") {
				continue
			}

			// Match an empty import decl if that's all that is available.
			if len(gen.Specs) == 0 && bestMatch == -1 {
				impDecl = gen
			}

			// Compute longest shared prefix with imports in this group.
			for j, spec := range gen.Specs {
				impspec := spec.(*ast.ImportSpec)
				n := matchLen(importPath(impspec), ipath)
				if n > bestMatch {
					bestMatch = n
					impDecl = gen
					impIndex = j
				}
			}
		}
	}

	// If no import decl found, add one after the last import.
	if impDecl == nil {
		impDecl = &ast.GenDecl{
			Tok: token.IMPORT,
		}
		if lastImport >= 0 {
			impDecl.TokPos = f.Decls[lastImport].End()
		} else {
			// There are no existing imports.
			// Our new import goes after the package declaration and after
			// the comment, if any, that starts on the same line as the
			// package declaration.
			impDecl.TokPos = f.Package

			file := fset.File(f.Package)
			pkgLine := file.Line(f.Package)
			for _, c := range f.Comments {
				if file.Line(c.Pos()) > pkgLine {
					break
				}
				impDecl.TokPos = c.End()
			}
		}
		f.Decls = append(f.Decls, nil)
		copy(f.Decls[lastImport+2:], f.Decls[lastImport+1:])
		f.Decls[lastImport+1] = impDecl
	}

	// Insert new import at insertAt.
	insertAt := 0
	if impIndex >= 0 {
		// insert after the found import
		insertAt = impIndex + 1
	}
	impDecl.Specs = append(impDecl.Specs, nil)
	copy(impDecl.Specs[insertAt+1:], impDecl.Specs[insertAt:])
	impDecl.Specs[insertAt] = newImport
	pos := impDecl.Pos()
	if insertAt > 0 {
		// If there is a comment after an existing import, preserve the comment
//.........这里部分代码省略.........

// DeleteNamedImport deletes the import with the given name and path from the file f, if present.
func DeleteNamedImport(fset *token.FileSet, f *ast.File, name, path string) (deleted bool) {
	var delspecs []*ast.ImportSpec

	// Find the import nodes that import path, if any.
	for i := 0; i < len(f.Decls); i++ {
		decl := f.Decls[i]
		gen, ok := decl.(*ast.GenDecl)
		if !ok || gen.Tok != token.IMPORT {
			continue
		}
		for j := 0; j < len(gen.Specs); j++ {
			spec := gen.Specs[j]
			impspec := spec.(*ast.ImportSpec)
			if impspec.Name == nil && name != "" {
				continue
			}
			if impspec.Name != nil && impspec.Name.Name != name {
				continue
			}
			if importPath(impspec) != path {
				continue
			}

			// We found an import spec that imports path.
			// Delete it.
			delspecs = append(delspecs, impspec)
			deleted = true
			copy(gen.Specs[j:], gen.Specs[j+1:])
			gen.Specs = gen.Specs[:len(gen.Specs)-1]

			// If this was the last import spec in this decl,
			// delete the decl, too.
			if len(gen.Specs) == 0 {
				copy(f.Decls[i:], f.Decls[i+1:])
				f.Decls = f.Decls[:len(f.Decls)-1]
				i--
				break
			} else if len(gen.Specs) == 1 {
				gen.Lparen = token.NoPos // drop parens
			}
			if j > 0 {
				lastImpspec := gen.Specs[j-1].(*ast.ImportSpec)
				lastLine := fset.Position(lastImpspec.Path.ValuePos).Line
				line := fset.Position(impspec.Path.ValuePos).Line

				// We deleted an entry but now there may be
				// a blank line-sized hole where the import was.
				if line-lastLine > 1 {
					// There was a blank line immediately preceding the deleted import,
					// so there's no need to close the hole.
					// Do nothing.
				} else {
					// There was no blank line. Close the hole.
					fset.File(gen.Rparen).MergeLine(line)
				}
			}
			j--
		}
	}

	// Delete them from f.Imports.
	for i := 0; i < len(f.Imports); i++ {
		imp := f.Imports[i]
		for j, del := range delspecs {
			if imp == del {
				copy(f.Imports[i:], f.Imports[i+1:])
				f.Imports = f.Imports[:len(f.Imports)-1]
				copy(delspecs[j:], delspecs[j+1:])
				delspecs = delspecs[:len(delspecs)-1]
				i--
				break
			}
		}
	}

	if len(delspecs) > 0 {
		panic(fmt.Sprintf("deleted specs from Decls but not Imports: %v", delspecs))
	}

	return
}

func fileWithAnnotationComments(file *ast.File, fset, oldFset *token.FileSet, src []byte) ([]byte, *ast.File, error) {
	// TODO: So this is an extremely hacky way of doing this. We're going to
	// add the comments directly to the source comments, as text, and then
	// we're going to re-parse it. This is because I tried manipulating the
	// AST, adding the commments there an shifting the nodes' positions, but
	// doing that right is very very convoluted; you need to be tracking all
	// the time where you are, where you _were_, figure out where's a line
	// break, etc. So, well, this will do for now.
	var err error
	var dstChunks [][]byte
	var lastChunkEnd int
	skipNextSpec := false
	addDoc := func(node ast.Node, name *ast.Ident, typ ast.Expr) {
		if typ == nil {
			return
		}
		if name != nil && len(name.Name) > 0 {
			c := name.Name[0]
			if !(c >= 'A' && c <= 'Z') {
				return
			}
		}
		buf := &bytes.Buffer{}
		err = printer.Fprint(buf, token.NewFileSet(), typ)
		if err != nil {
			return
		}
		pos := int(node.Pos()) - oldFset.File(file.Pos()).Base()
		var space []byte
		for i := pos - 1; i >= 0 && (src[i] == ' ' || src[i] == '\t'); i-- {
			space = append([]byte{src[i]}, space...)
		}
		text := append([]byte("// For SGo: "+buf.String()+"\n"), space...)
		dstChunks = append(dstChunks, src[lastChunkEnd:pos], text)
		lastChunkEnd = pos
	}
	var visitor visitorFunc
	visitor = visitorFunc(func(node ast.Node) (w ast.Visitor) {
		var typ ast.Expr
		var name *ast.Ident
		switch node := node.(type) {
		case *ast.FuncDecl:
			typ = node.Type
			name = node.Name
		case *ast.GenDecl:
			if node.Lparen != 0 || node.Tok == token.IMPORT || node.Tok == token.CONST {
				return visitor
			}
			switch spec := node.Specs[0].(type) {
			case *ast.TypeSpec:
				skipNextSpec = true
				typ = spec.Type
				name = spec.Name
			case *ast.ValueSpec:
				skipNextSpec = true
				typ = spec.Type
				if len(spec.Names.List) > 0 {
					name = spec.Names.List[0]
				}
			}
			switch typ.(type) {
			case *ast.InterfaceType, *ast.StructType:
				return visitor
			}
		case *ast.InterfaceType:
			for i := 0; i < len(node.Methods.List); i++ {
				item := node.Methods.List[i]
				if len(item.Names) > 0 {
					name = item.Names[0]
				}
				addDoc(item, name, item.Type)
			}
			return visitor
		case *ast.StructType:
			for i := 0; i < len(node.Fields.List); i++ {
				item := node.Fields.List[i]
				if len(item.Names) > 0 {
					name = item.Names[0]
				}
				addDoc(item, name, item.Type)
			}
			return visitor
		case *ast.TypeSpec:
			if skipNextSpec {
				skipNextSpec = false
				return visitor
			}
			typ = node.Type
			name = node.Name
		case *ast.ValueSpec:
			if skipNextSpec {
				skipNextSpec = false
				return visitor
			}
			typ = node.Type
			if len(node.Names.List) > 0 {
				name = node.Names.List[0]
			}
		default:
			return visitor
//.........这里部分代码省略.........