| // Copyright 2009 The Go Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style |
| // license that can be found in the LICENSE file. |
| |
| // Parse input AST and prepare Prog structure. |
| |
| package main |
| |
| import ( |
| "fmt" |
| "go/ast" |
| "go/parser" |
| "go/scanner" |
| "go/token" |
| "os" |
| "path/filepath" |
| "strings" |
| ) |
| |
| func parse(name string, flags parser.Mode) *ast.File { |
| ast1, err := parser.ParseFile(fset, name, nil, flags) |
| if err != nil { |
| if list, ok := err.(scanner.ErrorList); ok { |
| // If err is a scanner.ErrorList, its String will print just |
| // the first error and then (+n more errors). |
| // Instead, turn it into a new Error that will return |
| // details for all the errors. |
| for _, e := range list { |
| fmt.Fprintln(os.Stderr, e) |
| } |
| os.Exit(2) |
| } |
| fatalf("parsing %s: %s", name, err) |
| } |
| return ast1 |
| } |
| |
| func sourceLine(n ast.Node) int { |
| return fset.Position(n.Pos()).Line |
| } |
| |
| // ReadGo populates f with information learned from reading the |
| // Go source file with the given file name. It gathers the C preamble |
| // attached to the import "C" comment, a list of references to C.xxx, |
| // a list of exported functions, and the actual AST, to be rewritten and |
| // printed. |
| func (f *File) ReadGo(name string) { |
| // Create absolute path for file, so that it will be used in error |
| // messages and recorded in debug line number information. |
| // This matches the rest of the toolchain. See golang.org/issue/5122. |
| if aname, err := filepath.Abs(name); err == nil { |
| name = aname |
| } |
| |
| // Two different parses: once with comments, once without. |
| // The printer is not good enough at printing comments in the |
| // right place when we start editing the AST behind its back, |
| // so we use ast1 to look for the doc comments on import "C" |
| // and on exported functions, and we use ast2 for translating |
| // and reprinting. |
| ast1 := parse(name, parser.ParseComments) |
| ast2 := parse(name, 0) |
| |
| f.Package = ast1.Name.Name |
| f.Name = make(map[string]*Name) |
| |
| // In ast1, find the import "C" line and get any extra C preamble. |
| sawC := false |
| for _, decl := range ast1.Decls { |
| d, ok := decl.(*ast.GenDecl) |
| if !ok { |
| continue |
| } |
| for _, spec := range d.Specs { |
| s, ok := spec.(*ast.ImportSpec) |
| if !ok || s.Path.Value != `"C"` { |
| continue |
| } |
| sawC = true |
| if s.Name != nil { |
| error_(s.Path.Pos(), `cannot rename import "C"`) |
| } |
| cg := s.Doc |
| if cg == nil && len(d.Specs) == 1 { |
| cg = d.Doc |
| } |
| if cg != nil { |
| f.Preamble += fmt.Sprintf("#line %d %q\n", sourceLine(cg), name) |
| f.Preamble += commentText(cg) + "\n" |
| f.Preamble += "#line 1 \"cgo-generated-wrapper\"\n" |
| } |
| } |
| } |
| if !sawC { |
| error_(token.NoPos, `cannot find import "C"`) |
| } |
| |
| // In ast2, strip the import "C" line. |
| w := 0 |
| for _, decl := range ast2.Decls { |
| d, ok := decl.(*ast.GenDecl) |
| if !ok { |
| ast2.Decls[w] = decl |
| w++ |
| continue |
| } |
| ws := 0 |
| for _, spec := range d.Specs { |
| s, ok := spec.(*ast.ImportSpec) |
| if !ok || s.Path.Value != `"C"` { |
| d.Specs[ws] = spec |
| ws++ |
| } |
| } |
| if ws == 0 { |
| continue |
| } |
| d.Specs = d.Specs[0:ws] |
| ast2.Decls[w] = d |
| w++ |
| } |
| ast2.Decls = ast2.Decls[0:w] |
| |
| // Accumulate pointers to uses of C.x. |
| if f.Ref == nil { |
| f.Ref = make([]*Ref, 0, 8) |
| } |
| f.walk(ast2, "prog", (*File).saveExprs) |
| |
| // Accumulate exported functions. |
| // The comments are only on ast1 but we need to |
| // save the function bodies from ast2. |
| // The first walk fills in ExpFunc, and the |
| // second walk changes the entries to |
| // refer to ast2 instead. |
| f.walk(ast1, "prog", (*File).saveExport) |
| f.walk(ast2, "prog", (*File).saveExport2) |
| |
| f.Comments = ast1.Comments |
| f.AST = ast2 |
| } |
| |
| // Like ast.CommentGroup's Text method but preserves |
| // leading blank lines, so that line numbers line up. |
| func commentText(g *ast.CommentGroup) string { |
| if g == nil { |
| return "" |
| } |
| var pieces []string |
| for _, com := range g.List { |
| c := com.Text |
| // Remove comment markers. |
| // The parser has given us exactly the comment text. |
| switch c[1] { |
| case '/': |
| //-style comment (no newline at the end) |
| c = c[2:] + "\n" |
| case '*': |
| /*-style comment */ |
| c = c[2 : len(c)-2] |
| } |
| pieces = append(pieces, c) |
| } |
| return strings.Join(pieces, "") |
| } |
| |
| // Save various references we are going to need later. |
| func (f *File) saveExprs(x interface{}, context string) { |
| switch x := x.(type) { |
| case *ast.Expr: |
| switch (*x).(type) { |
| case *ast.SelectorExpr: |
| f.saveRef(x, context) |
| } |
| case *ast.CallExpr: |
| f.saveCall(x, context) |
| } |
| } |
| |
| // Save references to C.xxx for later processing. |
| func (f *File) saveRef(n *ast.Expr, context string) { |
| sel := (*n).(*ast.SelectorExpr) |
| // For now, assume that the only instance of capital C is when |
| // used as the imported package identifier. |
| // The parser should take care of scoping in the future, so |
| // that we will be able to distinguish a "top-level C" from a |
| // local C. |
| if l, ok := sel.X.(*ast.Ident); !ok || l.Name != "C" { |
| return |
| } |
| if context == "as2" { |
| context = "expr" |
| } |
| if context == "embed-type" { |
| error_(sel.Pos(), "cannot embed C type") |
| } |
| goname := sel.Sel.Name |
| if goname == "errno" { |
| error_(sel.Pos(), "cannot refer to errno directly; see documentation") |
| return |
| } |
| if goname == "_CMalloc" { |
| error_(sel.Pos(), "cannot refer to C._CMalloc; use C.malloc") |
| return |
| } |
| if goname == "malloc" { |
| goname = "_CMalloc" |
| } |
| name := f.Name[goname] |
| if name == nil { |
| name = &Name{ |
| Go: goname, |
| } |
| f.Name[goname] = name |
| } |
| f.Ref = append(f.Ref, &Ref{ |
| Name: name, |
| Expr: n, |
| Context: context, |
| }) |
| } |
| |
| // Save calls to C.xxx for later processing. |
| func (f *File) saveCall(call *ast.CallExpr, context string) { |
| sel, ok := call.Fun.(*ast.SelectorExpr) |
| if !ok { |
| return |
| } |
| if l, ok := sel.X.(*ast.Ident); !ok || l.Name != "C" { |
| return |
| } |
| c := &Call{Call: call, Deferred: context == "defer"} |
| f.Calls = append(f.Calls, c) |
| } |
| |
| // If a function should be exported add it to ExpFunc. |
| func (f *File) saveExport(x interface{}, context string) { |
| n, ok := x.(*ast.FuncDecl) |
| if !ok { |
| return |
| } |
| |
| if n.Doc == nil { |
| return |
| } |
| for _, c := range n.Doc.List { |
| if !strings.HasPrefix(c.Text, "//export ") { |
| continue |
| } |
| |
| name := strings.TrimSpace(c.Text[9:]) |
| if name == "" { |
| error_(c.Pos(), "export missing name") |
| } |
| |
| if name != n.Name.Name { |
| error_(c.Pos(), "export comment has wrong name %q, want %q", name, n.Name.Name) |
| } |
| |
| doc := "" |
| for _, c1 := range n.Doc.List { |
| if c1 != c { |
| doc += c1.Text + "\n" |
| } |
| } |
| |
| f.ExpFunc = append(f.ExpFunc, &ExpFunc{ |
| Func: n, |
| ExpName: name, |
| Doc: doc, |
| }) |
| break |
| } |
| } |
| |
| // Make f.ExpFunc[i] point at the Func from this AST instead of the other one. |
| func (f *File) saveExport2(x interface{}, context string) { |
| n, ok := x.(*ast.FuncDecl) |
| if !ok { |
| return |
| } |
| |
| for _, exp := range f.ExpFunc { |
| if exp.Func.Name.Name == n.Name.Name { |
| exp.Func = n |
| break |
| } |
| } |
| } |
| |
| // walk walks the AST x, calling visit(f, x, context) for each node. |
| func (f *File) walk(x interface{}, context string, visit func(*File, interface{}, string)) { |
| visit(f, x, context) |
| switch n := x.(type) { |
| case *ast.Expr: |
| f.walk(*n, context, visit) |
| |
| // everything else just recurs |
| default: |
| error_(token.NoPos, "unexpected type %T in walk", x) |
| panic("unexpected type") |
| |
| case nil: |
| |
| // These are ordered and grouped to match ../../go/ast/ast.go |
| case *ast.Field: |
| if len(n.Names) == 0 && context == "field" { |
| f.walk(&n.Type, "embed-type", visit) |
| } else { |
| f.walk(&n.Type, "type", visit) |
| } |
| case *ast.FieldList: |
| for _, field := range n.List { |
| f.walk(field, context, visit) |
| } |
| case *ast.BadExpr: |
| case *ast.Ident: |
| case *ast.Ellipsis: |
| case *ast.BasicLit: |
| case *ast.FuncLit: |
| f.walk(n.Type, "type", visit) |
| f.walk(n.Body, "stmt", visit) |
| case *ast.CompositeLit: |
| f.walk(&n.Type, "type", visit) |
| f.walk(n.Elts, "expr", visit) |
| case *ast.ParenExpr: |
| f.walk(&n.X, context, visit) |
| case *ast.SelectorExpr: |
| f.walk(&n.X, "selector", visit) |
| case *ast.IndexExpr: |
| f.walk(&n.X, "expr", visit) |
| f.walk(&n.Index, "expr", visit) |
| case *ast.SliceExpr: |
| f.walk(&n.X, "expr", visit) |
| if n.Low != nil { |
| f.walk(&n.Low, "expr", visit) |
| } |
| if n.High != nil { |
| f.walk(&n.High, "expr", visit) |
| } |
| if n.Max != nil { |
| f.walk(&n.Max, "expr", visit) |
| } |
| case *ast.TypeAssertExpr: |
| f.walk(&n.X, "expr", visit) |
| f.walk(&n.Type, "type", visit) |
| case *ast.CallExpr: |
| if context == "as2" { |
| f.walk(&n.Fun, "call2", visit) |
| } else { |
| f.walk(&n.Fun, "call", visit) |
| } |
| f.walk(n.Args, "expr", visit) |
| case *ast.StarExpr: |
| f.walk(&n.X, context, visit) |
| case *ast.UnaryExpr: |
| f.walk(&n.X, "expr", visit) |
| case *ast.BinaryExpr: |
| f.walk(&n.X, "expr", visit) |
| f.walk(&n.Y, "expr", visit) |
| case *ast.KeyValueExpr: |
| f.walk(&n.Key, "expr", visit) |
| f.walk(&n.Value, "expr", visit) |
| |
| case *ast.ArrayType: |
| f.walk(&n.Len, "expr", visit) |
| f.walk(&n.Elt, "type", visit) |
| case *ast.StructType: |
| f.walk(n.Fields, "field", visit) |
| case *ast.FuncType: |
| f.walk(n.Params, "param", visit) |
| if n.Results != nil { |
| f.walk(n.Results, "param", visit) |
| } |
| case *ast.InterfaceType: |
| f.walk(n.Methods, "field", visit) |
| case *ast.MapType: |
| f.walk(&n.Key, "type", visit) |
| f.walk(&n.Value, "type", visit) |
| case *ast.ChanType: |
| f.walk(&n.Value, "type", visit) |
| |
| case *ast.BadStmt: |
| case *ast.DeclStmt: |
| f.walk(n.Decl, "decl", visit) |
| case *ast.EmptyStmt: |
| case *ast.LabeledStmt: |
| f.walk(n.Stmt, "stmt", visit) |
| case *ast.ExprStmt: |
| f.walk(&n.X, "expr", visit) |
| case *ast.SendStmt: |
| f.walk(&n.Chan, "expr", visit) |
| f.walk(&n.Value, "expr", visit) |
| case *ast.IncDecStmt: |
| f.walk(&n.X, "expr", visit) |
| case *ast.AssignStmt: |
| f.walk(n.Lhs, "expr", visit) |
| if len(n.Lhs) == 2 && len(n.Rhs) == 1 { |
| f.walk(n.Rhs, "as2", visit) |
| } else { |
| f.walk(n.Rhs, "expr", visit) |
| } |
| case *ast.GoStmt: |
| f.walk(n.Call, "expr", visit) |
| case *ast.DeferStmt: |
| f.walk(n.Call, "defer", visit) |
| case *ast.ReturnStmt: |
| f.walk(n.Results, "expr", visit) |
| case *ast.BranchStmt: |
| case *ast.BlockStmt: |
| f.walk(n.List, context, visit) |
| case *ast.IfStmt: |
| f.walk(n.Init, "stmt", visit) |
| f.walk(&n.Cond, "expr", visit) |
| f.walk(n.Body, "stmt", visit) |
| f.walk(n.Else, "stmt", visit) |
| case *ast.CaseClause: |
| if context == "typeswitch" { |
| context = "type" |
| } else { |
| context = "expr" |
| } |
| f.walk(n.List, context, visit) |
| f.walk(n.Body, "stmt", visit) |
| case *ast.SwitchStmt: |
| f.walk(n.Init, "stmt", visit) |
| f.walk(&n.Tag, "expr", visit) |
| f.walk(n.Body, "switch", visit) |
| case *ast.TypeSwitchStmt: |
| f.walk(n.Init, "stmt", visit) |
| f.walk(n.Assign, "stmt", visit) |
| f.walk(n.Body, "typeswitch", visit) |
| case *ast.CommClause: |
| f.walk(n.Comm, "stmt", visit) |
| f.walk(n.Body, "stmt", visit) |
| case *ast.SelectStmt: |
| f.walk(n.Body, "stmt", visit) |
| case *ast.ForStmt: |
| f.walk(n.Init, "stmt", visit) |
| f.walk(&n.Cond, "expr", visit) |
| f.walk(n.Post, "stmt", visit) |
| f.walk(n.Body, "stmt", visit) |
| case *ast.RangeStmt: |
| f.walk(&n.Key, "expr", visit) |
| f.walk(&n.Value, "expr", visit) |
| f.walk(&n.X, "expr", visit) |
| f.walk(n.Body, "stmt", visit) |
| |
| case *ast.ImportSpec: |
| case *ast.ValueSpec: |
| f.walk(&n.Type, "type", visit) |
| if len(n.Names) == 2 && len(n.Values) == 1 { |
| f.walk(&n.Values[0], "as2", visit) |
| } else { |
| f.walk(n.Values, "expr", visit) |
| } |
| case *ast.TypeSpec: |
| f.walk(&n.Type, "type", visit) |
| |
| case *ast.BadDecl: |
| case *ast.GenDecl: |
| f.walk(n.Specs, "spec", visit) |
| case *ast.FuncDecl: |
| if n.Recv != nil { |
| f.walk(n.Recv, "param", visit) |
| } |
| f.walk(n.Type, "type", visit) |
| if n.Body != nil { |
| f.walk(n.Body, "stmt", visit) |
| } |
| |
| case *ast.File: |
| f.walk(n.Decls, "decl", visit) |
| |
| case *ast.Package: |
| for _, file := range n.Files { |
| f.walk(file, "file", visit) |
| } |
| |
| case []ast.Decl: |
| for _, d := range n { |
| f.walk(d, context, visit) |
| } |
| case []ast.Expr: |
| for i := range n { |
| f.walk(&n[i], context, visit) |
| } |
| case []ast.Stmt: |
| for _, s := range n { |
| f.walk(s, context, visit) |
| } |
| case []ast.Spec: |
| for _, s := range n { |
| f.walk(s, context, visit) |
| } |
| } |
| } |
