Golang ast.File类代码示例

func (p *printer) file(src *ast.File) {
	p.setComment(src.Doc)
	p.print(src.Pos(), token.PACKAGE, blank)
	p.expr(src.Name)
	p.declList(src.Decls)
	p.print(newline)
}

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)
}

func removeEmptyDeclGroups(f *ast.File) {
	i := 0
	for _, d := range f.Decls {
		if g, ok := d.(*ast.GenDecl); !ok || !isEmpty(f, g) {
			f.Decls[i] = d
			i++
		}
	}
	f.Decls = f.Decls[:i]
}

// fileExports removes unexported declarations from src in place.
//
func (r *reader) fileExports(src *ast.File) {
	j := 0
	for _, d := range src.Decls {
		if r.filterDecl(d) {
			src.Decls[j] = d
			j++
		}
	}
	src.Decls = src.Decls[0:j]
}

// 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)
			}
		}
	}
}

// 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.........

// readFile adds the AST for a source file to the reader.
//
func (r *reader) readFile(src *ast.File) {
	// add package documentation
	if src.Doc != nil {
		r.readDoc(src.Doc)
		src.Doc = nil // doc consumed - remove from AST
	}

	// add all declarations
	for _, decl := range src.Decls {
		switch d := decl.(type) {
		case *ast.GenDecl:
			switch d.Tok {
			case token.IMPORT:
				// imports are handled individually
				for _, spec := range d.Specs {
					if s, ok := spec.(*ast.ImportSpec); ok {
						if import_, err := strconv.Unquote(s.Path.Value); err == nil {
							r.imports[import_] = 1
							if s.Name != nil && s.Name.Name == "." {
								r.hasDotImp = true
							}
						}
					}
				}
			case token.CONST, token.VAR:
				// constants and variables are always handled as a group
				r.readValue(d)
			case token.TYPE:
				// types are handled individually
				if len(d.Specs) == 1 && !d.Lparen.IsValid() {
					// common case: single declaration w/o parentheses
					// (if a single declaration is parenthesized,
					// create a new fake declaration below, so that
					// go/doc type declarations always appear w/o
					// parentheses)
					if s, ok := d.Specs[0].(*ast.TypeSpec); ok {
						r.readType(d, s)
					}
					break
				}
				for _, spec := range d.Specs {
					if s, ok := spec.(*ast.TypeSpec); ok {
						// use an individual (possibly fake) declaration
						// for each type; this also ensures that each type
						// gets to (re-)use the declaration documentation
						// if there's none associated with the spec itself
						fake := &ast.GenDecl{
							Doc: d.Doc,
							// don't use the existing TokPos because it
							// will lead to the wrong selection range for
							// the fake declaration if there are more
							// than one type in the group (this affects
							// src/cmd/godoc/godoc.go's posLink_urlFunc)
							TokPos: s.Pos(),
							Tok:    token.TYPE,
							Specs:  []ast.Spec{s},
						}
						r.readType(fake, s)
					}
				}
			}
		case *ast.FuncDecl:
			r.readFunc(d)
		}
	}

	// collect MARKER(...): annotations
	r.readNotes(src.Comments)
	src.Comments = nil // consumed unassociated comments - remove from AST
}