diff options
Diffstat (limited to 'vendor/golang.org/x/tools/go/internal/gcimporter/gcimporter.go')
| -rw-r--r-- | vendor/golang.org/x/tools/go/internal/gcimporter/gcimporter.go | 1078 |
1 files changed, 1078 insertions, 0 deletions
diff --git a/vendor/golang.org/x/tools/go/internal/gcimporter/gcimporter.go b/vendor/golang.org/x/tools/go/internal/gcimporter/gcimporter.go new file mode 100644 index 0000000..8dcd8bb --- /dev/null +++ b/vendor/golang.org/x/tools/go/internal/gcimporter/gcimporter.go @@ -0,0 +1,1078 @@ +// Copyright 2011 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. + +// This file is a modified copy of $GOROOT/src/go/internal/gcimporter/gcimporter.go, +// but it also contains the original source-based importer code for Go1.6. +// Once we stop supporting 1.6, we can remove that code. + +// Package gcimporter provides various functions for reading +// gc-generated object files that can be used to implement the +// Importer interface defined by the Go 1.5 standard library package. +package gcimporter // import "golang.org/x/tools/go/internal/gcimporter" + +import ( + "bufio" + "errors" + "fmt" + "go/build" + "go/constant" + "go/token" + "go/types" + "io" + "io/ioutil" + "os" + "path/filepath" + "sort" + "strconv" + "strings" + "text/scanner" +) + +// debugging/development support +const debug = false + +var pkgExts = [...]string{".a", ".o"} + +// FindPkg returns the filename and unique package id for an import +// path based on package information provided by build.Import (using +// the build.Default build.Context). A relative srcDir is interpreted +// relative to the current working directory. +// If no file was found, an empty filename is returned. +// +func FindPkg(path, srcDir string) (filename, id string) { + if path == "" { + return + } + + var noext string + switch { + default: + // "x" -> "$GOPATH/pkg/$GOOS_$GOARCH/x.ext", "x" + // Don't require the source files to be present. + if abs, err := filepath.Abs(srcDir); err == nil { // see issue 14282 + srcDir = abs + } + bp, _ := build.Import(path, srcDir, build.FindOnly|build.AllowBinary) + if bp.PkgObj == "" { + id = path // make sure we have an id to print in error message + return + } + noext = strings.TrimSuffix(bp.PkgObj, ".a") + id = bp.ImportPath + + case build.IsLocalImport(path): + // "./x" -> "/this/directory/x.ext", "/this/directory/x" + noext = filepath.Join(srcDir, path) + id = noext + + case filepath.IsAbs(path): + // for completeness only - go/build.Import + // does not support absolute imports + // "/x" -> "/x.ext", "/x" + noext = path + id = path + } + + if false { // for debugging + if path != id { + fmt.Printf("%s -> %s\n", path, id) + } + } + + // try extensions + for _, ext := range pkgExts { + filename = noext + ext + if f, err := os.Stat(filename); err == nil && !f.IsDir() { + return + } + } + + filename = "" // not found + return +} + +// ImportData imports a package by reading the gc-generated export data, +// adds the corresponding package object to the packages map indexed by id, +// and returns the object. +// +// The packages map must contains all packages already imported. The data +// reader position must be the beginning of the export data section. The +// filename is only used in error messages. +// +// If packages[id] contains the completely imported package, that package +// can be used directly, and there is no need to call this function (but +// there is also no harm but for extra time used). +// +func ImportData(packages map[string]*types.Package, filename, id string, data io.Reader) (pkg *types.Package, err error) { + // support for parser error handling + defer func() { + switch r := recover().(type) { + case nil: + // nothing to do + case importError: + err = r + default: + panic(r) // internal error + } + }() + + var p parser + p.init(filename, id, data, packages) + pkg = p.parseExport() + + return +} + +// Import imports a gc-generated package given its import path and srcDir, adds +// the corresponding package object to the packages map, and returns the object. +// The packages map must contain all packages already imported. +// +func Import(packages map[string]*types.Package, path, srcDir string, lookup func(path string) (io.ReadCloser, error)) (pkg *types.Package, err error) { + var rc io.ReadCloser + var filename, id string + if lookup != nil { + // With custom lookup specified, assume that caller has + // converted path to a canonical import path for use in the map. + if path == "unsafe" { + return types.Unsafe, nil + } + id = path + + // No need to re-import if the package was imported completely before. + if pkg = packages[id]; pkg != nil && pkg.Complete() { + return + } + f, err := lookup(path) + if err != nil { + return nil, err + } + rc = f + } else { + filename, id = FindPkg(path, srcDir) + if filename == "" { + if path == "unsafe" { + return types.Unsafe, nil + } + return nil, fmt.Errorf("can't find import: %q", id) + } + + // no need to re-import if the package was imported completely before + if pkg = packages[id]; pkg != nil && pkg.Complete() { + return + } + + // open file + f, err := os.Open(filename) + if err != nil { + return nil, err + } + defer func() { + if err != nil { + // add file name to error + err = fmt.Errorf("%s: %v", filename, err) + } + }() + rc = f + } + defer rc.Close() + + var hdr string + buf := bufio.NewReader(rc) + if hdr, err = FindExportData(buf); err != nil { + return + } + + switch hdr { + case "$$\n": + // Work-around if we don't have a filename; happens only if lookup != nil. + // Either way, the filename is only needed for importer error messages, so + // this is fine. + if filename == "" { + filename = path + } + return ImportData(packages, filename, id, buf) + + case "$$B\n": + var data []byte + data, err = ioutil.ReadAll(buf) + if err != nil { + break + } + + // TODO(gri): allow clients of go/importer to provide a FileSet. + // Or, define a new standard go/types/gcexportdata package. + fset := token.NewFileSet() + + // The indexed export format starts with an 'i'; the older + // binary export format starts with a 'c', 'd', or 'v' + // (from "version"). Select appropriate importer. + if len(data) > 0 && data[0] == 'i' { + _, pkg, err = IImportData(fset, packages, data[1:], id) + } else { + _, pkg, err = BImportData(fset, packages, data, id) + } + + default: + err = fmt.Errorf("unknown export data header: %q", hdr) + } + + return +} + +// ---------------------------------------------------------------------------- +// Parser + +// TODO(gri) Imported objects don't have position information. +// Ideally use the debug table line info; alternatively +// create some fake position (or the position of the +// import). That way error messages referring to imported +// objects can print meaningful information. + +// parser parses the exports inside a gc compiler-produced +// object/archive file and populates its scope with the results. +type parser struct { + scanner scanner.Scanner + tok rune // current token + lit string // literal string; only valid for Ident, Int, String tokens + id string // package id of imported package + sharedPkgs map[string]*types.Package // package id -> package object (across importer) + localPkgs map[string]*types.Package // package id -> package object (just this package) +} + +func (p *parser) init(filename, id string, src io.Reader, packages map[string]*types.Package) { + p.scanner.Init(src) + p.scanner.Error = func(_ *scanner.Scanner, msg string) { p.error(msg) } + p.scanner.Mode = scanner.ScanIdents | scanner.ScanInts | scanner.ScanChars | scanner.ScanStrings | scanner.ScanComments | scanner.SkipComments + p.scanner.Whitespace = 1<<'\t' | 1<<' ' + p.scanner.Filename = filename // for good error messages + p.next() + p.id = id + p.sharedPkgs = packages + if debug { + // check consistency of packages map + for _, pkg := range packages { + if pkg.Name() == "" { + fmt.Printf("no package name for %s\n", pkg.Path()) + } + } + } +} + +func (p *parser) next() { + p.tok = p.scanner.Scan() + switch p.tok { + case scanner.Ident, scanner.Int, scanner.Char, scanner.String, '·': + p.lit = p.scanner.TokenText() + default: + p.lit = "" + } + if debug { + fmt.Printf("%s: %q -> %q\n", scanner.TokenString(p.tok), p.scanner.TokenText(), p.lit) + } +} + +func declTypeName(pkg *types.Package, name string) *types.TypeName { + scope := pkg.Scope() + if obj := scope.Lookup(name); obj != nil { + return obj.(*types.TypeName) + } + obj := types.NewTypeName(token.NoPos, pkg, name, nil) + // a named type may be referred to before the underlying type + // is known - set it up + types.NewNamed(obj, nil, nil) + scope.Insert(obj) + return obj +} + +// ---------------------------------------------------------------------------- +// Error handling + +// Internal errors are boxed as importErrors. +type importError struct { + pos scanner.Position + err error +} + +func (e importError) Error() string { + return fmt.Sprintf("import error %s (byte offset = %d): %s", e.pos, e.pos.Offset, e.err) +} + +func (p *parser) error(err interface{}) { + if s, ok := err.(string); ok { + err = errors.New(s) + } + // panic with a runtime.Error if err is not an error + panic(importError{p.scanner.Pos(), err.(error)}) +} + +func (p *parser) errorf(format string, args ...interface{}) { + p.error(fmt.Sprintf(format, args...)) +} + +func (p *parser) expect(tok rune) string { + lit := p.lit + if p.tok != tok { + p.errorf("expected %s, got %s (%s)", scanner.TokenString(tok), scanner.TokenString(p.tok), lit) + } + p.next() + return lit +} + +func (p *parser) expectSpecial(tok string) { + sep := 'x' // not white space + i := 0 + for i < len(tok) && p.tok == rune(tok[i]) && sep > ' ' { + sep = p.scanner.Peek() // if sep <= ' ', there is white space before the next token + p.next() + i++ + } + if i < len(tok) { + p.errorf("expected %q, got %q", tok, tok[0:i]) + } +} + +func (p *parser) expectKeyword(keyword string) { + lit := p.expect(scanner.Ident) + if lit != keyword { + p.errorf("expected keyword %s, got %q", keyword, lit) + } +} + +// ---------------------------------------------------------------------------- +// Qualified and unqualified names + +// PackageId = string_lit . +// +func (p *parser) parsePackageID() string { + id, err := strconv.Unquote(p.expect(scanner.String)) + if err != nil { + p.error(err) + } + // id == "" stands for the imported package id + // (only known at time of package installation) + if id == "" { + id = p.id + } + return id +} + +// PackageName = ident . +// +func (p *parser) parsePackageName() string { + return p.expect(scanner.Ident) +} + +// dotIdentifier = ( ident | '·' ) { ident | int | '·' } . +func (p *parser) parseDotIdent() string { + ident := "" + if p.tok != scanner.Int { + sep := 'x' // not white space + for (p.tok == scanner.Ident || p.tok == scanner.Int || p.tok == '·') && sep > ' ' { + ident += p.lit + sep = p.scanner.Peek() // if sep <= ' ', there is white space before the next token + p.next() + } + } + if ident == "" { + p.expect(scanner.Ident) // use expect() for error handling + } + return ident +} + +// QualifiedName = "@" PackageId "." ( "?" | dotIdentifier ) . +// +func (p *parser) parseQualifiedName() (id, name string) { + p.expect('@') + id = p.parsePackageID() + p.expect('.') + // Per rev f280b8a485fd (10/2/2013), qualified names may be used for anonymous fields. + if p.tok == '?' { + p.next() + } else { + name = p.parseDotIdent() + } + return +} + +// getPkg returns the package for a given id. If the package is +// not found, create the package and add it to the p.localPkgs +// and p.sharedPkgs maps. name is the (expected) name of the +// package. If name == "", the package name is expected to be +// set later via an import clause in the export data. +// +// id identifies a package, usually by a canonical package path like +// "encoding/json" but possibly by a non-canonical import path like +// "./json". +// +func (p *parser) getPkg(id, name string) *types.Package { + // package unsafe is not in the packages maps - handle explicitly + if id == "unsafe" { + return types.Unsafe + } + + pkg := p.localPkgs[id] + if pkg == nil { + // first import of id from this package + pkg = p.sharedPkgs[id] + if pkg == nil { + // first import of id by this importer; + // add (possibly unnamed) pkg to shared packages + pkg = types.NewPackage(id, name) + p.sharedPkgs[id] = pkg + } + // add (possibly unnamed) pkg to local packages + if p.localPkgs == nil { + p.localPkgs = make(map[string]*types.Package) + } + p.localPkgs[id] = pkg + } else if name != "" { + // package exists already and we have an expected package name; + // make sure names match or set package name if necessary + if pname := pkg.Name(); pname == "" { + pkg.SetName(name) + } else if pname != name { + p.errorf("%s package name mismatch: %s (given) vs %s (expected)", id, pname, name) + } + } + return pkg +} + +// parseExportedName is like parseQualifiedName, but +// the package id is resolved to an imported *types.Package. +// +func (p *parser) parseExportedName() (pkg *types.Package, name string) { + id, name := p.parseQualifiedName() + pkg = p.getPkg(id, "") + return +} + +// ---------------------------------------------------------------------------- +// Types + +// BasicType = identifier . +// +func (p *parser) parseBasicType() types.Type { + id := p.expect(scanner.Ident) + obj := types.Universe.Lookup(id) + if obj, ok := obj.(*types.TypeName); ok { + return obj.Type() + } + p.errorf("not a basic type: %s", id) + return nil +} + +// ArrayType = "[" int_lit "]" Type . +// +func (p *parser) parseArrayType(parent *types.Package) types.Type { + // "[" already consumed and lookahead known not to be "]" + lit := p.expect(scanner.Int) + p.expect(']') + elem := p.parseType(parent) + n, err := strconv.ParseInt(lit, 10, 64) + if err != nil { + p.error(err) + } + return types.NewArray(elem, n) +} + +// MapType = "map" "[" Type "]" Type . +// +func (p *parser) parseMapType(parent *types.Package) types.Type { + p.expectKeyword("map") + p.expect('[') + key := p.parseType(parent) + p.expect(']') + elem := p.parseType(parent) + return types.NewMap(key, elem) +} + +// Name = identifier | "?" | QualifiedName . +// +// For unqualified and anonymous names, the returned package is the parent +// package unless parent == nil, in which case the returned package is the +// package being imported. (The parent package is not nil if the the name +// is an unqualified struct field or interface method name belonging to a +// type declared in another package.) +// +// For qualified names, the returned package is nil (and not created if +// it doesn't exist yet) unless materializePkg is set (which creates an +// unnamed package with valid package path). In the latter case, a +// subsequent import clause is expected to provide a name for the package. +// +func (p *parser) parseName(parent *types.Package, materializePkg bool) (pkg *types.Package, name string) { + pkg = parent + if pkg == nil { + pkg = p.sharedPkgs[p.id] + } + switch p.tok { + case scanner.Ident: + name = p.lit + p.next() + case '?': + // anonymous + p.next() + case '@': + // exported name prefixed with package path + pkg = nil + var id string + id, name = p.parseQualifiedName() + if materializePkg { + pkg = p.getPkg(id, "") + } + default: + p.error("name expected") + } + return +} + +func deref(typ types.Type) types.Type { + if p, _ := typ.(*types.Pointer); p != nil { + return p.Elem() + } + return typ +} + +// Field = Name Type [ string_lit ] . +// +func (p *parser) parseField(parent *types.Package) (*types.Var, string) { + pkg, name := p.parseName(parent, true) + + if name == "_" { + // Blank fields should be package-qualified because they + // are unexported identifiers, but gc does not qualify them. + // Assuming that the ident belongs to the current package + // causes types to change during re-exporting, leading + // to spurious "can't assign A to B" errors from go/types. + // As a workaround, pretend all blank fields belong + // to the same unique dummy package. + const blankpkg = "<_>" + pkg = p.getPkg(blankpkg, blankpkg) + } + + typ := p.parseType(parent) + anonymous := false + if name == "" { + // anonymous field - typ must be T or *T and T must be a type name + switch typ := deref(typ).(type) { + case *types.Basic: // basic types are named types + pkg = nil // objects defined in Universe scope have no package + name = typ.Name() + case *types.Named: + name = typ.Obj().Name() + default: + p.errorf("anonymous field expected") + } + anonymous = true + } + tag := "" + if p.tok == scanner.String { + s := p.expect(scanner.String) + var err error + tag, err = strconv.Unquote(s) + if err != nil { + p.errorf("invalid struct tag %s: %s", s, err) + } + } + return types.NewField(token.NoPos, pkg, name, typ, anonymous), tag +} + +// StructType = "struct" "{" [ FieldList ] "}" . +// FieldList = Field { ";" Field } . +// +func (p *parser) parseStructType(parent *types.Package) types.Type { + var fields []*types.Var + var tags []string + + p.expectKeyword("struct") + p.expect('{') + for i := 0; p.tok != '}' && p.tok != scanner.EOF; i++ { + if i > 0 { + p.expect(';') + } + fld, tag := p.parseField(parent) + if tag != "" && tags == nil { + tags = make([]string, i) + } + if tags != nil { + tags = append(tags, tag) + } + fields = append(fields, fld) + } + p.expect('}') + + return types.NewStruct(fields, tags) +} + +// Parameter = ( identifier | "?" ) [ "..." ] Type [ string_lit ] . +// +func (p *parser) parseParameter() (par *types.Var, isVariadic bool) { + _, name := p.parseName(nil, false) + // remove gc-specific parameter numbering + if i := strings.Index(name, "·"); i >= 0 { + name = name[:i] + } + if p.tok == '.' { + p.expectSpecial("...") + isVariadic = true + } + typ := p.parseType(nil) + if isVariadic { + typ = types.NewSlice(typ) + } + // ignore argument tag (e.g. "noescape") + if p.tok == scanner.String { + p.next() + } + // TODO(gri) should we provide a package? + par = types.NewVar(token.NoPos, nil, name, typ) + return +} + +// Parameters = "(" [ ParameterList ] ")" . +// ParameterList = { Parameter "," } Parameter . +// +func (p *parser) parseParameters() (list []*types.Var, isVariadic bool) { + p.expect('(') + for p.tok != ')' && p.tok != scanner.EOF { + if len(list) > 0 { + p.expect(',') + } + par, variadic := p.parseParameter() + list = append(list, par) + if variadic { + if isVariadic { + p.error("... not on final argument") + } + isVariadic = true + } + } + p.expect(')') + + return +} + +// Signature = Parameters [ Result ] . +// Result = Type | Parameters . +// +func (p *parser) parseSignature(recv *types.Var) *types.Signature { + params, isVariadic := p.parseParameters() + + // optional result type + var results []*types.Var + if p.tok == '(' { + var variadic bool + results, variadic = p.parseParameters() + if variadic { + p.error("... not permitted on result type") + } + } + + return types.NewSignature(recv, types.NewTuple(params...), types.NewTuple(results...), isVariadic) +} + +// InterfaceType = "interface" "{" [ MethodList ] "}" . +// MethodList = Method { ";" Method } . +// Method = Name Signature . +// +// The methods of embedded interfaces are always "inlined" +// by the compiler and thus embedded interfaces are never +// visible in the export data. +// +func (p *parser) parseInterfaceType(parent *types.Package) types.Type { + var methods []*types.Func + + p.expectKeyword("interface") + p.expect('{') + for i := 0; p.tok != '}' && p.tok != scanner.EOF; i++ { + if i > 0 { + p.expect(';') + } + pkg, name := p.parseName(parent, true) + sig := p.parseSignature(nil) + methods = append(methods, types.NewFunc(token.NoPos, pkg, name, sig)) + } + p.expect('}') + + // Complete requires the type's embedded interfaces to be fully defined, + // but we do not define any + return newInterface(methods, nil).Complete() +} + +// ChanType = ( "chan" [ "<-" ] | "<-" "chan" ) Type . +// +func (p *parser) parseChanType(parent *types.Package) types.Type { + dir := types.SendRecv + if p.tok == scanner.Ident { + p.expectKeyword("chan") + if p.tok == '<' { + p.expectSpecial("<-") + dir = types.SendOnly + } + } else { + p.expectSpecial("<-") + p.expectKeyword("chan") + dir = types.RecvOnly + } + elem := p.parseType(parent) + return types.NewChan(dir, elem) +} + +// Type = +// BasicType | TypeName | ArrayType | SliceType | StructType | +// PointerType | FuncType | InterfaceType | MapType | ChanType | +// "(" Type ")" . +// +// BasicType = ident . +// TypeName = ExportedName . +// SliceType = "[" "]" Type . +// PointerType = "*" Type . +// FuncType = "func" Signature . +// +func (p *parser) parseType(parent *types.Package) types.Type { + switch p.tok { + case scanner.Ident: + switch p.lit { + default: + return p.parseBasicType() + case "struct": + return p.parseStructType(parent) + case "func": + // FuncType + p.next() + return p.parseSignature(nil) + case "interface": + return p.parseInterfaceType(parent) + case "map": + return p.parseMapType(parent) + case "chan": + return p.parseChanType(parent) + } + case '@': + // TypeName + pkg, name := p.parseExportedName() + return declTypeName(pkg, name).Type() + case '[': + p.next() // look ahead + if p.tok == ']' { + // SliceType + p.next() + return types.NewSlice(p.parseType(parent)) + } + return p.parseArrayType(parent) + case '*': + // PointerType + p.next() + return types.NewPointer(p.parseType(parent)) + case '<': + return p.parseChanType(parent) + case '(': + // "(" Type ")" + p.next() + typ := p.parseType(parent) + p.expect(')') + return typ + } + p.errorf("expected type, got %s (%q)", scanner.TokenString(p.tok), p.lit) + return nil +} + +// ---------------------------------------------------------------------------- +// Declarations + +// ImportDecl = "import" PackageName PackageId . +// +func (p *parser) parseImportDecl() { + p.expectKeyword("import") + name := p.parsePackageName() + p.getPkg(p.parsePackageID(), name) +} + +// int_lit = [ "+" | "-" ] { "0" ... "9" } . +// +func (p *parser) parseInt() string { + s := "" + switch p.tok { + case '-': + s = "-" + p.next() + case '+': + p.next() + } + return s + p.expect(scanner.Int) +} + +// number = int_lit [ "p" int_lit ] . +// +func (p *parser) parseNumber() (typ *types.Basic, val constant.Value) { + // mantissa + mant := constant.MakeFromLiteral(p.parseInt(), token.INT, 0) + if mant == nil { + panic("invalid mantissa") + } + + if p.lit == "p" { + // exponent (base 2) + p.next() + exp, err := strconv.ParseInt(p.parseInt(), 10, 0) + if err != nil { + p.error(err) + } + if exp < 0 { + denom := constant.MakeInt64(1) + denom = constant.Shift(denom, token.SHL, uint(-exp)) + typ = types.Typ[types.UntypedFloat] + val = constant.BinaryOp(mant, token.QUO, denom) + return + } + if exp > 0 { + mant = constant.Shift(mant, token.SHL, uint(exp)) + } + typ = types.Typ[types.UntypedFloat] + val = mant + return + } + + typ = types.Typ[types.UntypedInt] + val = mant + return +} + +// ConstDecl = "const" ExportedName [ Type ] "=" Literal . +// Literal = bool_lit | int_lit | float_lit | complex_lit | rune_lit | string_lit . +// bool_lit = "true" | "false" . +// complex_lit = "(" float_lit "+" float_lit "i" ")" . +// rune_lit = "(" int_lit "+" int_lit ")" . +// string_lit = `"` { unicode_char } `"` . +// +func (p *parser) parseConstDecl() { + p.expectKeyword("const") + pkg, name := p.parseExportedName() + + var typ0 types.Type + if p.tok != '=' { + // constant types are never structured - no need for parent type + typ0 = p.parseType(nil) + } + + p.expect('=') + var typ types.Type + var val constant.Value + switch p.tok { + case scanner.Ident: + // bool_lit + if p.lit != "true" && p.lit != "false" { + p.error("expected true or false") + } + typ = types.Typ[types.UntypedBool] + val = constant.MakeBool(p.lit == "true") + p.next() + + case '-', scanner.Int: + // int_lit + typ, val = p.parseNumber() + + case '(': + // complex_lit or rune_lit + p.next() + if p.tok == scanner.Char { + p.next() + p.expect('+') + typ = types.Typ[types.UntypedRune] + _, val = p.parseNumber() + p.expect(')') + break + } + _, re := p.parseNumber() + p.expect('+') + _, im := p.parseNumber() + p.expectKeyword("i") + p.expect(')') + typ = types.Typ[types.UntypedComplex] + val = constant.BinaryOp(re, token.ADD, constant.MakeImag(im)) + + case scanner.Char: + // rune_lit + typ = types.Typ[types.UntypedRune] + val = constant.MakeFromLiteral(p.lit, token.CHAR, 0) + p.next() + + case scanner.String: + // string_lit + typ = types.Typ[types.UntypedString] + val = constant.MakeFromLiteral(p.lit, token.STRING, 0) + p.next() + + default: + p.errorf("expected literal got %s", scanner.TokenString(p.tok)) + } + + if typ0 == nil { + typ0 = typ + } + + pkg.Scope().Insert(types.NewConst(token.NoPos, pkg, name, typ0, val)) +} + +// TypeDecl = "type" ExportedName Type . +// +func (p *parser) parseTypeDecl() { + p.expectKeyword("type") + pkg, name := p.parseExportedName() + obj := declTypeName(pkg, name) + + // The type object may have been imported before and thus already + // have a type associated with it. We still need to parse the type + // structure, but throw it away if the object already has a type. + // This ensures that all imports refer to the same type object for + // a given type declaration. + typ := p.parseType(pkg) + + if name := obj.Type().(*types.Named); name.Underlying() == nil { + name.SetUnderlying(typ) + } +} + +// VarDecl = "var" ExportedName Type . +// +func (p *parser) parseVarDecl() { + p.expectKeyword("var") + pkg, name := p.parseExportedName() + typ := p.parseType(pkg) + pkg.Scope().Insert(types.NewVar(token.NoPos, pkg, name, typ)) +} + +// Func = Signature [ Body ] . +// Body = "{" ... "}" . +// +func (p *parser) parseFunc(recv *types.Var) *types.Signature { + sig := p.parseSignature(recv) + if p.tok == '{' { + p.next() + for i := 1; i > 0; p.next() { + switch p.tok { + case '{': + i++ + case '}': + i-- + } + } + } + return sig +} + +// MethodDecl = "func" Receiver Name Func . +// Receiver = "(" ( identifier | "?" ) [ "*" ] ExportedName ")" . +// +func (p *parser) parseMethodDecl() { + // "func" already consumed + p.expect('(') + recv, _ := p.parseParameter() // receiver + p.expect(')') + + // determine receiver base type object + base := deref(recv.Type()).(*types.Named) + + // parse method name, signature, and possibly inlined body + _, name := p.parseName(nil, false) + sig := p.parseFunc(recv) + + // methods always belong to the same package as the base type object + pkg := base.Obj().Pkg() + + // add method to type unless type was imported before + // and method exists already + // TODO(gri) This leads to a quadratic algorithm - ok for now because method counts are small. + base.AddMethod(types.NewFunc(token.NoPos, pkg, name, sig)) +} + +// FuncDecl = "func" ExportedName Func . +// +func (p *parser) parseFuncDecl() { + // "func" already consumed + pkg, name := p.parseExportedName() + typ := p.parseFunc(nil) + pkg.Scope().Insert(types.NewFunc(token.NoPos, pkg, name, typ)) +} + +// Decl = [ ImportDecl | ConstDecl | TypeDecl | VarDecl | FuncDecl | MethodDecl ] "\n" . +// +func (p *parser) parseDecl() { + if p.tok == scanner.Ident { + switch p.lit { + case "import": + p.parseImportDecl() + case "const": + p.parseConstDecl() + case "type": + p.parseTypeDecl() + case "var": + p.parseVarDecl() + case "func": + p.next() // look ahead + if p.tok == '(' { + p.parseMethodDecl() + } else { + p.parseFuncDecl() + } + } + } + p.expect('\n') +} + +// ---------------------------------------------------------------------------- +// Export + +// Export = "PackageClause { Decl } "$$" . +// PackageClause = "package" PackageName [ "safe" ] "\n" . +// +func (p *parser) parseExport() *types.Package { + p.expectKeyword("package") + name := p.parsePackageName() + if p.tok == scanner.Ident && p.lit == "safe" { + // package was compiled with -u option - ignore + p.next() + } + p.expect('\n') + + pkg := p.getPkg(p.id, name) + + for p.tok != '$' && p.tok != scanner.EOF { + p.parseDecl() + } + + if ch := p.scanner.Peek(); p.tok != '$' || ch != '$' { + // don't call next()/expect() since reading past the + // export data may cause scanner errors (e.g. NUL chars) + p.errorf("expected '$$', got %s %c", scanner.TokenString(p.tok), ch) + } + + if n := p.scanner.ErrorCount; n != 0 { + p.errorf("expected no scanner errors, got %d", n) + } + + // Record all locally referenced packages as imports. + var imports []*types.Package + for id, pkg2 := range p.localPkgs { + if pkg2.Name() == "" { + p.errorf("%s package has no name", id) + } + if id == p.id { + continue // avoid self-edge + } + imports = append(imports, pkg2) + } + sort.Sort(byPath(imports)) + pkg.SetImports(imports) + + // package was imported completely and without errors + pkg.MarkComplete() + + return pkg +} + +type byPath []*types.Package + +func (a byPath) Len() int { return len(a) } +func (a byPath) Swap(i, j int) { a[i], a[j] = a[j], a[i] } +func (a byPath) Less(i, j int) bool { return a[i].Path() < a[j].Path() } |