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Source file src/go/doc/reader.go

Documentation: go/doc

     1  // Copyright 2009 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  package doc
     6  
     7  import (
     8  	"go/ast"
     9  	"go/token"
    10  	"sort"
    11  	"strconv"
    12  )
    13  
    14  // ----------------------------------------------------------------------------
    15  // function/method sets
    16  //
    17  // Internally, we treat functions like methods and collect them in method sets.
    18  
    19  // A methodSet describes a set of methods. Entries where Decl == nil are conflict
    20  // entries (more than one method with the same name at the same embedding level).
    21  //
    22  type methodSet map[string]*Func
    23  
    24  // recvString returns a string representation of recv of the
    25  // form "T", "*T", or "BADRECV" (if not a proper receiver type).
    26  //
    27  func recvString(recv ast.Expr) string {
    28  	switch t := recv.(type) {
    29  	case *ast.Ident:
    30  		return t.Name
    31  	case *ast.StarExpr:
    32  		return "*" + recvString(t.X)
    33  	}
    34  	return "BADRECV"
    35  }
    36  
    37  // set creates the corresponding Func for f and adds it to mset.
    38  // If there are multiple f's with the same name, set keeps the first
    39  // one with documentation; conflicts are ignored. The boolean
    40  // specifies whether to leave the AST untouched.
    41  //
    42  func (mset methodSet) set(f *ast.FuncDecl, preserveAST bool) {
    43  	name := f.Name.Name
    44  	if g := mset[name]; g != nil && g.Doc != "" {
    45  		// A function with the same name has already been registered;
    46  		// since it has documentation, assume f is simply another
    47  		// implementation and ignore it. This does not happen if the
    48  		// caller is using go/build.ScanDir to determine the list of
    49  		// files implementing a package.
    50  		return
    51  	}
    52  	// function doesn't exist or has no documentation; use f
    53  	recv := ""
    54  	if f.Recv != nil {
    55  		var typ ast.Expr
    56  		// be careful in case of incorrect ASTs
    57  		if list := f.Recv.List; len(list) == 1 {
    58  			typ = list[0].Type
    59  		}
    60  		recv = recvString(typ)
    61  	}
    62  	mset[name] = &Func{
    63  		Doc:  f.Doc.Text(),
    64  		Name: name,
    65  		Decl: f,
    66  		Recv: recv,
    67  		Orig: recv,
    68  	}
    69  	if !preserveAST {
    70  		f.Doc = nil // doc consumed - remove from AST
    71  	}
    72  }
    73  
    74  // add adds method m to the method set; m is ignored if the method set
    75  // already contains a method with the same name at the same or a higher
    76  // level than m.
    77  //
    78  func (mset methodSet) add(m *Func) {
    79  	old := mset[m.Name]
    80  	if old == nil || m.Level < old.Level {
    81  		mset[m.Name] = m
    82  		return
    83  	}
    84  	if m.Level == old.Level {
    85  		// conflict - mark it using a method with nil Decl
    86  		mset[m.Name] = &Func{
    87  			Name:  m.Name,
    88  			Level: m.Level,
    89  		}
    90  	}
    91  }
    92  
    93  // ----------------------------------------------------------------------------
    94  // Named types
    95  
    96  // baseTypeName returns the name of the base type of x (or "")
    97  // and whether the type is imported or not.
    98  //
    99  func baseTypeName(x ast.Expr) (name string, imported bool) {
   100  	switch t := x.(type) {
   101  	case *ast.Ident:
   102  		return t.Name, false
   103  	case *ast.SelectorExpr:
   104  		if _, ok := t.X.(*ast.Ident); ok {
   105  			// only possible for qualified type names;
   106  			// assume type is imported
   107  			return t.Sel.Name, true
   108  		}
   109  	case *ast.ParenExpr:
   110  		return baseTypeName(t.X)
   111  	case *ast.StarExpr:
   112  		return baseTypeName(t.X)
   113  	}
   114  	return
   115  }
   116  
   117  // An embeddedSet describes a set of embedded types.
   118  type embeddedSet map[*namedType]bool
   119  
   120  // A namedType represents a named unqualified (package local, or possibly
   121  // predeclared) type. The namedType for a type name is always found via
   122  // reader.lookupType.
   123  //
   124  type namedType struct {
   125  	doc  string       // doc comment for type
   126  	name string       // type name
   127  	decl *ast.GenDecl // nil if declaration hasn't been seen yet
   128  
   129  	isEmbedded bool        // true if this type is embedded
   130  	isStruct   bool        // true if this type is a struct
   131  	embedded   embeddedSet // true if the embedded type is a pointer
   132  
   133  	// associated declarations
   134  	values  []*Value // consts and vars
   135  	funcs   methodSet
   136  	methods methodSet
   137  }
   138  
   139  // ----------------------------------------------------------------------------
   140  // AST reader
   141  
   142  // reader accumulates documentation for a single package.
   143  // It modifies the AST: Comments (declaration documentation)
   144  // that have been collected by the reader are set to nil
   145  // in the respective AST nodes so that they are not printed
   146  // twice (once when printing the documentation and once when
   147  // printing the corresponding AST node).
   148  //
   149  type reader struct {
   150  	mode Mode
   151  
   152  	// package properties
   153  	doc       string // package documentation, if any
   154  	filenames []string
   155  	notes     map[string][]*Note
   156  
   157  	// declarations
   158  	imports   map[string]int
   159  	hasDotImp bool     // if set, package contains a dot import
   160  	values    []*Value // consts and vars
   161  	order     int      // sort order of const and var declarations (when we can't use a name)
   162  	types     map[string]*namedType
   163  	funcs     methodSet
   164  
   165  	// support for package-local error type declarations
   166  	errorDecl bool                 // if set, type "error" was declared locally
   167  	fixlist   []*ast.InterfaceType // list of interfaces containing anonymous field "error"
   168  }
   169  
   170  func (r *reader) isVisible(name string) bool {
   171  	return r.mode&AllDecls != 0 || ast.IsExported(name)
   172  }
   173  
   174  // lookupType returns the base type with the given name.
   175  // If the base type has not been encountered yet, a new
   176  // type with the given name but no associated declaration
   177  // is added to the type map.
   178  //
   179  func (r *reader) lookupType(name string) *namedType {
   180  	if name == "" || name == "_" {
   181  		return nil // no type docs for anonymous types
   182  	}
   183  	if typ, found := r.types[name]; found {
   184  		return typ
   185  	}
   186  	// type not found - add one without declaration
   187  	typ := &namedType{
   188  		name:     name,
   189  		embedded: make(embeddedSet),
   190  		funcs:    make(methodSet),
   191  		methods:  make(methodSet),
   192  	}
   193  	r.types[name] = typ
   194  	return typ
   195  }
   196  
   197  // recordAnonymousField registers fieldType as the type of an
   198  // anonymous field in the parent type. If the field is imported
   199  // (qualified name) or the parent is nil, the field is ignored.
   200  // The function returns the field name.
   201  //
   202  func (r *reader) recordAnonymousField(parent *namedType, fieldType ast.Expr) (fname string) {
   203  	fname, imp := baseTypeName(fieldType)
   204  	if parent == nil || imp {
   205  		return
   206  	}
   207  	if ftype := r.lookupType(fname); ftype != nil {
   208  		ftype.isEmbedded = true
   209  		_, ptr := fieldType.(*ast.StarExpr)
   210  		parent.embedded[ftype] = ptr
   211  	}
   212  	return
   213  }
   214  
   215  func (r *reader) readDoc(comment *ast.CommentGroup) {
   216  	// By convention there should be only one package comment
   217  	// but collect all of them if there are more than one.
   218  	text := comment.Text()
   219  	if r.doc == "" {
   220  		r.doc = text
   221  		return
   222  	}
   223  	r.doc += "\n" + text
   224  }
   225  
   226  func (r *reader) remember(typ *ast.InterfaceType) {
   227  	r.fixlist = append(r.fixlist, typ)
   228  }
   229  
   230  func specNames(specs []ast.Spec) []string {
   231  	names := make([]string, 0, len(specs)) // reasonable estimate
   232  	for _, s := range specs {
   233  		// s guaranteed to be an *ast.ValueSpec by readValue
   234  		for _, ident := range s.(*ast.ValueSpec).Names {
   235  			names = append(names, ident.Name)
   236  		}
   237  	}
   238  	return names
   239  }
   240  
   241  // readValue processes a const or var declaration.
   242  //
   243  func (r *reader) readValue(decl *ast.GenDecl) {
   244  	// determine if decl should be associated with a type
   245  	// Heuristic: For each typed entry, determine the type name, if any.
   246  	//            If there is exactly one type name that is sufficiently
   247  	//            frequent, associate the decl with the respective type.
   248  	domName := ""
   249  	domFreq := 0
   250  	prev := ""
   251  	n := 0
   252  	for _, spec := range decl.Specs {
   253  		s, ok := spec.(*ast.ValueSpec)
   254  		if !ok {
   255  			continue // should not happen, but be conservative
   256  		}
   257  		name := ""
   258  		switch {
   259  		case s.Type != nil:
   260  			// a type is present; determine its name
   261  			if n, imp := baseTypeName(s.Type); !imp {
   262  				name = n
   263  			}
   264  		case decl.Tok == token.CONST && len(s.Values) == 0:
   265  			// no type or value is present but we have a constant declaration;
   266  			// use the previous type name (possibly the empty string)
   267  			name = prev
   268  		}
   269  		if name != "" {
   270  			// entry has a named type
   271  			if domName != "" && domName != name {
   272  				// more than one type name - do not associate
   273  				// with any type
   274  				domName = ""
   275  				break
   276  			}
   277  			domName = name
   278  			domFreq++
   279  		}
   280  		prev = name
   281  		n++
   282  	}
   283  
   284  	// nothing to do w/o a legal declaration
   285  	if n == 0 {
   286  		return
   287  	}
   288  
   289  	// determine values list with which to associate the Value for this decl
   290  	values := &r.values
   291  	const threshold = 0.75
   292  	if domName != "" && r.isVisible(domName) && domFreq >= int(float64(len(decl.Specs))*threshold) {
   293  		// typed entries are sufficiently frequent
   294  		if typ := r.lookupType(domName); typ != nil {
   295  			values = &typ.values // associate with that type
   296  		}
   297  	}
   298  
   299  	*values = append(*values, &Value{
   300  		Doc:   decl.Doc.Text(),
   301  		Names: specNames(decl.Specs),
   302  		Decl:  decl,
   303  		order: r.order,
   304  	})
   305  	if r.mode&PreserveAST == 0 {
   306  		decl.Doc = nil // doc consumed - remove from AST
   307  	}
   308  	// Note: It's important that the order used here is global because the cleanupTypes
   309  	// methods may move values associated with types back into the global list. If the
   310  	// order is list-specific, sorting is not deterministic because the same order value
   311  	// may appear multiple times (was bug, found when fixing #16153).
   312  	r.order++
   313  }
   314  
   315  // fields returns a struct's fields or an interface's methods.
   316  //
   317  func fields(typ ast.Expr) (list []*ast.Field, isStruct bool) {
   318  	var fields *ast.FieldList
   319  	switch t := typ.(type) {
   320  	case *ast.StructType:
   321  		fields = t.Fields
   322  		isStruct = true
   323  	case *ast.InterfaceType:
   324  		fields = t.Methods
   325  	}
   326  	if fields != nil {
   327  		list = fields.List
   328  	}
   329  	return
   330  }
   331  
   332  // readType processes a type declaration.
   333  //
   334  func (r *reader) readType(decl *ast.GenDecl, spec *ast.TypeSpec) {
   335  	typ := r.lookupType(spec.Name.Name)
   336  	if typ == nil {
   337  		return // no name or blank name - ignore the type
   338  	}
   339  
   340  	// A type should be added at most once, so typ.decl
   341  	// should be nil - if it is not, simply overwrite it.
   342  	typ.decl = decl
   343  
   344  	// compute documentation
   345  	doc := spec.Doc
   346  	if doc == nil {
   347  		// no doc associated with the spec, use the declaration doc, if any
   348  		doc = decl.Doc
   349  	}
   350  	if r.mode&PreserveAST == 0 {
   351  		spec.Doc = nil // doc consumed - remove from AST
   352  		decl.Doc = nil // doc consumed - remove from AST
   353  	}
   354  	typ.doc = doc.Text()
   355  
   356  	// record anonymous fields (they may contribute methods)
   357  	// (some fields may have been recorded already when filtering
   358  	// exports, but that's ok)
   359  	var list []*ast.Field
   360  	list, typ.isStruct = fields(spec.Type)
   361  	for _, field := range list {
   362  		if len(field.Names) == 0 {
   363  			r.recordAnonymousField(typ, field.Type)
   364  		}
   365  	}
   366  }
   367  
   368  // isPredeclared reports whether n denotes a predeclared type.
   369  //
   370  func (r *reader) isPredeclared(n string) bool {
   371  	return predeclaredTypes[n] && r.types[n] == nil
   372  }
   373  
   374  // readFunc processes a func or method declaration.
   375  //
   376  func (r *reader) readFunc(fun *ast.FuncDecl) {
   377  	// strip function body if requested.
   378  	if r.mode&PreserveAST == 0 {
   379  		fun.Body = nil
   380  	}
   381  
   382  	// associate methods with the receiver type, if any
   383  	if fun.Recv != nil {
   384  		// method
   385  		if len(fun.Recv.List) == 0 {
   386  			// should not happen (incorrect AST); (See issue 17788)
   387  			// don't show this method
   388  			return
   389  		}
   390  		recvTypeName, imp := baseTypeName(fun.Recv.List[0].Type)
   391  		if imp {
   392  			// should not happen (incorrect AST);
   393  			// don't show this method
   394  			return
   395  		}
   396  		if typ := r.lookupType(recvTypeName); typ != nil {
   397  			typ.methods.set(fun, r.mode&PreserveAST != 0)
   398  		}
   399  		// otherwise ignore the method
   400  		// TODO(gri): There may be exported methods of non-exported types
   401  		// that can be called because of exported values (consts, vars, or
   402  		// function results) of that type. Could determine if that is the
   403  		// case and then show those methods in an appropriate section.
   404  		return
   405  	}
   406  
   407  	// Associate factory functions with the first visible result type, as long as
   408  	// others are predeclared types.
   409  	if fun.Type.Results.NumFields() >= 1 {
   410  		var typ *namedType // type to associate the function with
   411  		numResultTypes := 0
   412  		for _, res := range fun.Type.Results.List {
   413  			factoryType := res.Type
   414  			if t, ok := factoryType.(*ast.ArrayType); ok {
   415  				// We consider functions that return slices or arrays of type
   416  				// T (or pointers to T) as factory functions of T.
   417  				factoryType = t.Elt
   418  			}
   419  			if n, imp := baseTypeName(factoryType); !imp && r.isVisible(n) && !r.isPredeclared(n) {
   420  				if t := r.lookupType(n); t != nil {
   421  					typ = t
   422  					numResultTypes++
   423  					if numResultTypes > 1 {
   424  						break
   425  					}
   426  				}
   427  			}
   428  		}
   429  		// If there is exactly one result type,
   430  		// associate the function with that type.
   431  		if numResultTypes == 1 {
   432  			typ.funcs.set(fun, r.mode&PreserveAST != 0)
   433  			return
   434  		}
   435  	}
   436  
   437  	// just an ordinary function
   438  	r.funcs.set(fun, r.mode&PreserveAST != 0)
   439  }
   440  
   441  var (
   442  	noteMarker    = `([A-Z][A-Z]+)\(([^)]+)\):?`           // MARKER(uid), MARKER at least 2 chars, uid at least 1 char
   443  	noteMarkerRx  = newLazyRE(`^[ \t]*` + noteMarker)      // MARKER(uid) at text start
   444  	noteCommentRx = newLazyRE(`^/[/*][ \t]*` + noteMarker) // MARKER(uid) at comment start
   445  )
   446  
   447  // readNote collects a single note from a sequence of comments.
   448  //
   449  func (r *reader) readNote(list []*ast.Comment) {
   450  	text := (&ast.CommentGroup{List: list}).Text()
   451  	if m := noteMarkerRx.FindStringSubmatchIndex(text); m != nil {
   452  		// The note body starts after the marker.
   453  		// We remove any formatting so that we don't
   454  		// get spurious line breaks/indentation when
   455  		// showing the TODO body.
   456  		body := clean(text[m[1]:], keepNL)
   457  		if body != "" {
   458  			marker := text[m[2]:m[3]]
   459  			r.notes[marker] = append(r.notes[marker], &Note{
   460  				Pos:  list[0].Pos(),
   461  				End:  list[len(list)-1].End(),
   462  				UID:  text[m[4]:m[5]],
   463  				Body: body,
   464  			})
   465  		}
   466  	}
   467  }
   468  
   469  // readNotes extracts notes from comments.
   470  // A note must start at the beginning of a comment with "MARKER(uid):"
   471  // and is followed by the note body (e.g., "// BUG(gri): fix this").
   472  // The note ends at the end of the comment group or at the start of
   473  // another note in the same comment group, whichever comes first.
   474  //
   475  func (r *reader) readNotes(comments []*ast.CommentGroup) {
   476  	for _, group := range comments {
   477  		i := -1 // comment index of most recent note start, valid if >= 0
   478  		list := group.List
   479  		for j, c := range list {
   480  			if noteCommentRx.MatchString(c.Text) {
   481  				if i >= 0 {
   482  					r.readNote(list[i:j])
   483  				}
   484  				i = j
   485  			}
   486  		}
   487  		if i >= 0 {
   488  			r.readNote(list[i:])
   489  		}
   490  	}
   491  }
   492  
   493  // readFile adds the AST for a source file to the reader.
   494  //
   495  func (r *reader) readFile(src *ast.File) {
   496  	// add package documentation
   497  	if src.Doc != nil {
   498  		r.readDoc(src.Doc)
   499  		if r.mode&PreserveAST == 0 {
   500  			src.Doc = nil // doc consumed - remove from AST
   501  		}
   502  	}
   503  
   504  	// add all declarations but for functions which are processed in a separate pass
   505  	for _, decl := range src.Decls {
   506  		switch d := decl.(type) {
   507  		case *ast.GenDecl:
   508  			switch d.Tok {
   509  			case token.IMPORT:
   510  				// imports are handled individually
   511  				for _, spec := range d.Specs {
   512  					if s, ok := spec.(*ast.ImportSpec); ok {
   513  						if import_, err := strconv.Unquote(s.Path.Value); err == nil {
   514  							r.imports[import_] = 1
   515  							if s.Name != nil && s.Name.Name == "." {
   516  								r.hasDotImp = true
   517  							}
   518  						}
   519  					}
   520  				}
   521  			case token.CONST, token.VAR:
   522  				// constants and variables are always handled as a group
   523  				r.readValue(d)
   524  			case token.TYPE:
   525  				// types are handled individually
   526  				if len(d.Specs) == 1 && !d.Lparen.IsValid() {
   527  					// common case: single declaration w/o parentheses
   528  					// (if a single declaration is parenthesized,
   529  					// create a new fake declaration below, so that
   530  					// go/doc type declarations always appear w/o
   531  					// parentheses)
   532  					if s, ok := d.Specs[0].(*ast.TypeSpec); ok {
   533  						r.readType(d, s)
   534  					}
   535  					break
   536  				}
   537  				for _, spec := range d.Specs {
   538  					if s, ok := spec.(*ast.TypeSpec); ok {
   539  						// use an individual (possibly fake) declaration
   540  						// for each type; this also ensures that each type
   541  						// gets to (re-)use the declaration documentation
   542  						// if there's none associated with the spec itself
   543  						fake := &ast.GenDecl{
   544  							Doc: d.Doc,
   545  							// don't use the existing TokPos because it
   546  							// will lead to the wrong selection range for
   547  							// the fake declaration if there are more
   548  							// than one type in the group (this affects
   549  							// src/cmd/godoc/godoc.go's posLink_urlFunc)
   550  							TokPos: s.Pos(),
   551  							Tok:    token.TYPE,
   552  							Specs:  []ast.Spec{s},
   553  						}
   554  						r.readType(fake, s)
   555  					}
   556  				}
   557  			}
   558  		}
   559  	}
   560  
   561  	// collect MARKER(...): annotations
   562  	r.readNotes(src.Comments)
   563  	if r.mode&PreserveAST == 0 {
   564  		src.Comments = nil // consumed unassociated comments - remove from AST
   565  	}
   566  }
   567  
   568  func (r *reader) readPackage(pkg *ast.Package, mode Mode) {
   569  	// initialize reader
   570  	r.filenames = make([]string, len(pkg.Files))
   571  	r.imports = make(map[string]int)
   572  	r.mode = mode
   573  	r.types = make(map[string]*namedType)
   574  	r.funcs = make(methodSet)
   575  	r.notes = make(map[string][]*Note)
   576  
   577  	// sort package files before reading them so that the
   578  	// result does not depend on map iteration order
   579  	i := 0
   580  	for filename := range pkg.Files {
   581  		r.filenames[i] = filename
   582  		i++
   583  	}
   584  	sort.Strings(r.filenames)
   585  
   586  	// process files in sorted order
   587  	for _, filename := range r.filenames {
   588  		f := pkg.Files[filename]
   589  		if mode&AllDecls == 0 {
   590  			r.fileExports(f)
   591  		}
   592  		r.readFile(f)
   593  	}
   594  
   595  	// process functions now that we have better type information
   596  	for _, f := range pkg.Files {
   597  		for _, decl := range f.Decls {
   598  			if d, ok := decl.(*ast.FuncDecl); ok {
   599  				r.readFunc(d)
   600  			}
   601  		}
   602  	}
   603  }
   604  
   605  // ----------------------------------------------------------------------------
   606  // Types
   607  
   608  func customizeRecv(f *Func, recvTypeName string, embeddedIsPtr bool, level int) *Func {
   609  	if f == nil || f.Decl == nil || f.Decl.Recv == nil || len(f.Decl.Recv.List) != 1 {
   610  		return f // shouldn't happen, but be safe
   611  	}
   612  
   613  	// copy existing receiver field and set new type
   614  	newField := *f.Decl.Recv.List[0]
   615  	origPos := newField.Type.Pos()
   616  	_, origRecvIsPtr := newField.Type.(*ast.StarExpr)
   617  	newIdent := &ast.Ident{NamePos: origPos, Name: recvTypeName}
   618  	var typ ast.Expr = newIdent
   619  	if !embeddedIsPtr && origRecvIsPtr {
   620  		newIdent.NamePos++ // '*' is one character
   621  		typ = &ast.StarExpr{Star: origPos, X: newIdent}
   622  	}
   623  	newField.Type = typ
   624  
   625  	// copy existing receiver field list and set new receiver field
   626  	newFieldList := *f.Decl.Recv
   627  	newFieldList.List = []*ast.Field{&newField}
   628  
   629  	// copy existing function declaration and set new receiver field list
   630  	newFuncDecl := *f.Decl
   631  	newFuncDecl.Recv = &newFieldList
   632  
   633  	// copy existing function documentation and set new declaration
   634  	newF := *f
   635  	newF.Decl = &newFuncDecl
   636  	newF.Recv = recvString(typ)
   637  	// the Orig field never changes
   638  	newF.Level = level
   639  
   640  	return &newF
   641  }
   642  
   643  // collectEmbeddedMethods collects the embedded methods of typ in mset.
   644  //
   645  func (r *reader) collectEmbeddedMethods(mset methodSet, typ *namedType, recvTypeName string, embeddedIsPtr bool, level int, visited embeddedSet) {
   646  	visited[typ] = true
   647  	for embedded, isPtr := range typ.embedded {
   648  		// Once an embedded type is embedded as a pointer type
   649  		// all embedded types in those types are treated like
   650  		// pointer types for the purpose of the receiver type
   651  		// computation; i.e., embeddedIsPtr is sticky for this
   652  		// embedding hierarchy.
   653  		thisEmbeddedIsPtr := embeddedIsPtr || isPtr
   654  		for _, m := range embedded.methods {
   655  			// only top-level methods are embedded
   656  			if m.Level == 0 {
   657  				mset.add(customizeRecv(m, recvTypeName, thisEmbeddedIsPtr, level))
   658  			}
   659  		}
   660  		if !visited[embedded] {
   661  			r.collectEmbeddedMethods(mset, embedded, recvTypeName, thisEmbeddedIsPtr, level+1, visited)
   662  		}
   663  	}
   664  	delete(visited, typ)
   665  }
   666  
   667  // computeMethodSets determines the actual method sets for each type encountered.
   668  //
   669  func (r *reader) computeMethodSets() {
   670  	for _, t := range r.types {
   671  		// collect embedded methods for t
   672  		if t.isStruct {
   673  			// struct
   674  			r.collectEmbeddedMethods(t.methods, t, t.name, false, 1, make(embeddedSet))
   675  		} else {
   676  			// interface
   677  			// TODO(gri) fix this
   678  		}
   679  	}
   680  
   681  	// if error was declared locally, don't treat it as exported field anymore
   682  	if r.errorDecl {
   683  		for _, ityp := range r.fixlist {
   684  			removeErrorField(ityp)
   685  		}
   686  	}
   687  }
   688  
   689  // cleanupTypes removes the association of functions and methods with
   690  // types that have no declaration. Instead, these functions and methods
   691  // are shown at the package level. It also removes types with missing
   692  // declarations or which are not visible.
   693  //
   694  func (r *reader) cleanupTypes() {
   695  	for _, t := range r.types {
   696  		visible := r.isVisible(t.name)
   697  		predeclared := predeclaredTypes[t.name]
   698  
   699  		if t.decl == nil && (predeclared || visible && (t.isEmbedded || r.hasDotImp)) {
   700  			// t.name is a predeclared type (and was not redeclared in this package),
   701  			// or it was embedded somewhere but its declaration is missing (because
   702  			// the AST is incomplete), or we have a dot-import (and all bets are off):
   703  			// move any associated values, funcs, and methods back to the top-level so
   704  			// that they are not lost.
   705  			// 1) move values
   706  			r.values = append(r.values, t.values...)
   707  			// 2) move factory functions
   708  			for name, f := range t.funcs {
   709  				// in a correct AST, package-level function names
   710  				// are all different - no need to check for conflicts
   711  				r.funcs[name] = f
   712  			}
   713  			// 3) move methods
   714  			if !predeclared {
   715  				for name, m := range t.methods {
   716  					// don't overwrite functions with the same name - drop them
   717  					if _, found := r.funcs[name]; !found {
   718  						r.funcs[name] = m
   719  					}
   720  				}
   721  			}
   722  		}
   723  		// remove types w/o declaration or which are not visible
   724  		if t.decl == nil || !visible {
   725  			delete(r.types, t.name)
   726  		}
   727  	}
   728  }
   729  
   730  // ----------------------------------------------------------------------------
   731  // Sorting
   732  
   733  type data struct {
   734  	n    int
   735  	swap func(i, j int)
   736  	less func(i, j int) bool
   737  }
   738  
   739  func (d *data) Len() int           { return d.n }
   740  func (d *data) Swap(i, j int)      { d.swap(i, j) }
   741  func (d *data) Less(i, j int) bool { return d.less(i, j) }
   742  
   743  // sortBy is a helper function for sorting
   744  func sortBy(less func(i, j int) bool, swap func(i, j int), n int) {
   745  	sort.Sort(&data{n, swap, less})
   746  }
   747  
   748  func sortedKeys(m map[string]int) []string {
   749  	list := make([]string, len(m))
   750  	i := 0
   751  	for key := range m {
   752  		list[i] = key
   753  		i++
   754  	}
   755  	sort.Strings(list)
   756  	return list
   757  }
   758  
   759  // sortingName returns the name to use when sorting d into place.
   760  //
   761  func sortingName(d *ast.GenDecl) string {
   762  	if len(d.Specs) == 1 {
   763  		if s, ok := d.Specs[0].(*ast.ValueSpec); ok {
   764  			return s.Names[0].Name
   765  		}
   766  	}
   767  	return ""
   768  }
   769  
   770  func sortedValues(m []*Value, tok token.Token) []*Value {
   771  	list := make([]*Value, len(m)) // big enough in any case
   772  	i := 0
   773  	for _, val := range m {
   774  		if val.Decl.Tok == tok {
   775  			list[i] = val
   776  			i++
   777  		}
   778  	}
   779  	list = list[0:i]
   780  
   781  	sortBy(
   782  		func(i, j int) bool {
   783  			if ni, nj := sortingName(list[i].Decl), sortingName(list[j].Decl); ni != nj {
   784  				return ni < nj
   785  			}
   786  			return list[i].order < list[j].order
   787  		},
   788  		func(i, j int) { list[i], list[j] = list[j], list[i] },
   789  		len(list),
   790  	)
   791  
   792  	return list
   793  }
   794  
   795  func sortedTypes(m map[string]*namedType, allMethods bool) []*Type {
   796  	list := make([]*Type, len(m))
   797  	i := 0
   798  	for _, t := range m {
   799  		list[i] = &Type{
   800  			Doc:     t.doc,
   801  			Name:    t.name,
   802  			Decl:    t.decl,
   803  			Consts:  sortedValues(t.values, token.CONST),
   804  			Vars:    sortedValues(t.values, token.VAR),
   805  			Funcs:   sortedFuncs(t.funcs, true),
   806  			Methods: sortedFuncs(t.methods, allMethods),
   807  		}
   808  		i++
   809  	}
   810  
   811  	sortBy(
   812  		func(i, j int) bool { return list[i].Name < list[j].Name },
   813  		func(i, j int) { list[i], list[j] = list[j], list[i] },
   814  		len(list),
   815  	)
   816  
   817  	return list
   818  }
   819  
   820  func removeStar(s string) string {
   821  	if len(s) > 0 && s[0] == '*' {
   822  		return s[1:]
   823  	}
   824  	return s
   825  }
   826  
   827  func sortedFuncs(m methodSet, allMethods bool) []*Func {
   828  	list := make([]*Func, len(m))
   829  	i := 0
   830  	for _, m := range m {
   831  		// determine which methods to include
   832  		switch {
   833  		case m.Decl == nil:
   834  			// exclude conflict entry
   835  		case allMethods, m.Level == 0, !ast.IsExported(removeStar(m.Orig)):
   836  			// forced inclusion, method not embedded, or method
   837  			// embedded but original receiver type not exported
   838  			list[i] = m
   839  			i++
   840  		}
   841  	}
   842  	list = list[0:i]
   843  	sortBy(
   844  		func(i, j int) bool { return list[i].Name < list[j].Name },
   845  		func(i, j int) { list[i], list[j] = list[j], list[i] },
   846  		len(list),
   847  	)
   848  	return list
   849  }
   850  
   851  // noteBodies returns a list of note body strings given a list of notes.
   852  // This is only used to populate the deprecated Package.Bugs field.
   853  //
   854  func noteBodies(notes []*Note) []string {
   855  	var list []string
   856  	for _, n := range notes {
   857  		list = append(list, n.Body)
   858  	}
   859  	return list
   860  }
   861  
   862  // ----------------------------------------------------------------------------
   863  // Predeclared identifiers
   864  
   865  // IsPredeclared reports whether s is a predeclared identifier.
   866  func IsPredeclared(s string) bool {
   867  	return predeclaredTypes[s] || predeclaredFuncs[s] || predeclaredConstants[s]
   868  }
   869  
   870  var predeclaredTypes = map[string]bool{
   871  	"bool":       true,
   872  	"byte":       true,
   873  	"complex64":  true,
   874  	"complex128": true,
   875  	"error":      true,
   876  	"float32":    true,
   877  	"float64":    true,
   878  	"int":        true,
   879  	"int8":       true,
   880  	"int16":      true,
   881  	"int32":      true,
   882  	"int64":      true,
   883  	"rune":       true,
   884  	"string":     true,
   885  	"uint":       true,
   886  	"uint8":      true,
   887  	"uint16":     true,
   888  	"uint32":     true,
   889  	"uint64":     true,
   890  	"uintptr":    true,
   891  }
   892  
   893  var predeclaredFuncs = map[string]bool{
   894  	"append":  true,
   895  	"cap":     true,
   896  	"close":   true,
   897  	"complex": true,
   898  	"copy":    true,
   899  	"delete":  true,
   900  	"imag":    true,
   901  	"len":     true,
   902  	"make":    true,
   903  	"new":     true,
   904  	"panic":   true,
   905  	"print":   true,
   906  	"println": true,
   907  	"real":    true,
   908  	"recover": true,
   909  }
   910  
   911  var predeclaredConstants = map[string]bool{
   912  	"false": true,
   913  	"iota":  true,
   914  	"nil":   true,
   915  	"true":  true,
   916  }
   917  

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