Adding upstream version 1.16.10.upstream/1.16.10upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1085 insertions, 0 deletions

diff --git a/src/cmd/doc/pkg.go b/src/cmd/doc/pkg.go
new file mode 100644
index 0000000..c2e06eb
--- /dev/null
+++ b/src/cmd/doc/pkg.go
@@ -0,0 +1,1085 @@
+// Copyright 2015 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.
+
+package main
+
+import (
+	"bufio"
+	"bytes"
+	"fmt"
+	"go/ast"
+	"go/build"
+	"go/doc"
+	"go/format"
+	"go/parser"
+	"go/printer"
+	"go/token"
+	"io"
+	"io/fs"
+	"log"
+	"path/filepath"
+	"strings"
+	"unicode"
+	"unicode/utf8"
+)
+
+const (
+	punchedCardWidth = 80 // These things just won't leave us alone.
+	indentedWidth    = punchedCardWidth - len(indent)
+	indent           = "    "
+)
+
+type Package struct {
+	writer      io.Writer    // Destination for output.
+	name        string       // Package name, json for encoding/json.
+	userPath    string       // String the user used to find this package.
+	pkg         *ast.Package // Parsed package.
+	file        *ast.File    // Merged from all files in the package
+	doc         *doc.Package
+	build       *build.Package
+	typedValue  map[*doc.Value]bool // Consts and vars related to types.
+	constructor map[*doc.Func]bool  // Constructors.
+	fs          *token.FileSet      // Needed for printing.
+	buf         pkgBuffer
+}
+
+// pkgBuffer is a wrapper for bytes.Buffer that prints a package clause the
+// first time Write is called.
+type pkgBuffer struct {
+	pkg     *Package
+	printed bool // Prevent repeated package clauses.
+	bytes.Buffer
+}
+
+func (pb *pkgBuffer) Write(p []byte) (int, error) {
+	pb.packageClause()
+	return pb.Buffer.Write(p)
+}
+
+func (pb *pkgBuffer) packageClause() {
+	if !pb.printed {
+		pb.printed = true
+		// Only show package clause for commands if requested explicitly.
+		if pb.pkg.pkg.Name != "main" || showCmd {
+			pb.pkg.packageClause()
+		}
+	}
+}
+
+type PackageError string // type returned by pkg.Fatalf.
+
+func (p PackageError) Error() string {
+	return string(p)
+}
+
+// prettyPath returns a version of the package path that is suitable for an
+// error message. It obeys the import comment if present. Also, since
+// pkg.build.ImportPath is sometimes the unhelpful "" or ".", it looks for a
+// directory name in GOROOT or GOPATH if that happens.
+func (pkg *Package) prettyPath() string {
+	path := pkg.build.ImportComment
+	if path == "" {
+		path = pkg.build.ImportPath
+	}
+	if path != "." && path != "" {
+		return path
+	}
+	// Convert the source directory into a more useful path.
+	// Also convert everything to slash-separated paths for uniform handling.
+	path = filepath.Clean(filepath.ToSlash(pkg.build.Dir))
+	// Can we find a decent prefix?
+	goroot := filepath.Join(buildCtx.GOROOT, "src")
+	if p, ok := trim(path, filepath.ToSlash(goroot)); ok {
+		return p
+	}
+	for _, gopath := range splitGopath() {
+		if p, ok := trim(path, filepath.ToSlash(gopath)); ok {
+			return p
+		}
+	}
+	return path
+}
+
+// trim trims the directory prefix from the path, paying attention
+// to the path separator. If they are the same string or the prefix
+// is not present the original is returned. The boolean reports whether
+// the prefix is present. That path and prefix have slashes for separators.
+func trim(path, prefix string) (string, bool) {
+	if !strings.HasPrefix(path, prefix) {
+		return path, false
+	}
+	if path == prefix {
+		return path, true
+	}
+	if path[len(prefix)] == '/' {
+		return path[len(prefix)+1:], true
+	}
+	return path, false // Textual prefix but not a path prefix.
+}
+
+// pkg.Fatalf is like log.Fatalf, but panics so it can be recovered in the
+// main do function, so it doesn't cause an exit. Allows testing to work
+// without running a subprocess. The log prefix will be added when
+// logged in main; it is not added here.
+func (pkg *Package) Fatalf(format string, args ...interface{}) {
+	panic(PackageError(fmt.Sprintf(format, args...)))
+}
+
+// parsePackage turns the build package we found into a parsed package
+// we can then use to generate documentation.
+func parsePackage(writer io.Writer, pkg *build.Package, userPath string) *Package {
+	// include tells parser.ParseDir which files to include.
+	// That means the file must be in the build package's GoFiles or CgoFiles
+	// list only (no tag-ignored files, tests, swig or other non-Go files).
+	include := func(info fs.FileInfo) bool {
+		for _, name := range pkg.GoFiles {
+			if name == info.Name() {
+				return true
+			}
+		}
+		for _, name := range pkg.CgoFiles {
+			if name == info.Name() {
+				return true
+			}
+		}
+		return false
+	}
+	fset := token.NewFileSet()
+	pkgs, err := parser.ParseDir(fset, pkg.Dir, include, parser.ParseComments)
+	if err != nil {
+		log.Fatal(err)
+	}
+	// Make sure they are all in one package.
+	if len(pkgs) == 0 {
+		log.Fatalf("no source-code package in directory %s", pkg.Dir)
+	}
+	if len(pkgs) > 1 {
+		log.Fatalf("multiple packages in directory %s", pkg.Dir)
+	}
+	astPkg := pkgs[pkg.Name]
+
+	// TODO: go/doc does not include typed constants in the constants
+	// list, which is what we want. For instance, time.Sunday is of type
+	// time.Weekday, so it is defined in the type but not in the
+	// Consts list for the package. This prevents
+	//	go doc time.Sunday
+	// from finding the symbol. Work around this for now, but we
+	// should fix it in go/doc.
+	// A similar story applies to factory functions.
+	mode := doc.AllDecls
+	if showSrc {
+		mode |= doc.PreserveAST // See comment for Package.emit.
+	}
+	docPkg := doc.New(astPkg, pkg.ImportPath, mode)
+	typedValue := make(map[*doc.Value]bool)
+	constructor := make(map[*doc.Func]bool)
+	for _, typ := range docPkg.Types {
+		docPkg.Consts = append(docPkg.Consts, typ.Consts...)
+		docPkg.Vars = append(docPkg.Vars, typ.Vars...)
+		docPkg.Funcs = append(docPkg.Funcs, typ.Funcs...)
+		if isExported(typ.Name) {
+			for _, value := range typ.Consts {
+				typedValue[value] = true
+			}
+			for _, value := range typ.Vars {
+				typedValue[value] = true
+			}
+			for _, fun := range typ.Funcs {
+				// We don't count it as a constructor bound to the type
+				// if the type itself is not exported.
+				constructor[fun] = true
+			}
+		}
+	}
+
+	p := &Package{
+		writer:      writer,
+		name:        pkg.Name,
+		userPath:    userPath,
+		pkg:         astPkg,
+		file:        ast.MergePackageFiles(astPkg, 0),
+		doc:         docPkg,
+		typedValue:  typedValue,
+		constructor: constructor,
+		build:       pkg,
+		fs:          fset,
+	}
+	p.buf.pkg = p
+	return p
+}
+
+func (pkg *Package) Printf(format string, args ...interface{}) {
+	fmt.Fprintf(&pkg.buf, format, args...)
+}
+
+func (pkg *Package) flush() {
+	_, err := pkg.writer.Write(pkg.buf.Bytes())
+	if err != nil {
+		log.Fatal(err)
+	}
+	pkg.buf.Reset() // Not needed, but it's a flush.
+}
+
+var newlineBytes = []byte("\n\n") // We never ask for more than 2.
+
+// newlines guarantees there are n newlines at the end of the buffer.
+func (pkg *Package) newlines(n int) {
+	for !bytes.HasSuffix(pkg.buf.Bytes(), newlineBytes[:n]) {
+		pkg.buf.WriteRune('\n')
+	}
+}
+
+// emit prints the node. If showSrc is true, it ignores the provided comment,
+// assuming the comment is in the node itself. Otherwise, the go/doc package
+// clears the stuff we don't want to print anyway. It's a bit of a magic trick.
+func (pkg *Package) emit(comment string, node ast.Node) {
+	if node != nil {
+		var arg interface{} = node
+		if showSrc {
+			// Need an extra little dance to get internal comments to appear.
+			arg = &printer.CommentedNode{
+				Node:     node,
+				Comments: pkg.file.Comments,
+			}
+		}
+		err := format.Node(&pkg.buf, pkg.fs, arg)
+		if err != nil {
+			log.Fatal(err)
+		}
+		if comment != "" && !showSrc {
+			pkg.newlines(1)
+			doc.ToText(&pkg.buf, comment, indent, indent+indent, indentedWidth)
+			pkg.newlines(2) // Blank line after comment to separate from next item.
+		} else {
+			pkg.newlines(1)
+		}
+	}
+}
+
+// oneLineNode returns a one-line summary of the given input node.
+func (pkg *Package) oneLineNode(node ast.Node) string {
+	const maxDepth = 10
+	return pkg.oneLineNodeDepth(node, maxDepth)
+}
+
+// oneLineNodeDepth returns a one-line summary of the given input node.
+// The depth specifies the maximum depth when traversing the AST.
+func (pkg *Package) oneLineNodeDepth(node ast.Node, depth int) string {
+	const dotDotDot = "..."
+	if depth == 0 {
+		return dotDotDot
+	}
+	depth--
+
+	switch n := node.(type) {
+	case nil:
+		return ""
+
+	case *ast.GenDecl:
+		// Formats const and var declarations.
+		trailer := ""
+		if len(n.Specs) > 1 {
+			trailer = " " + dotDotDot
+		}
+
+		// Find the first relevant spec.
+		typ := ""
+		for i, spec := range n.Specs {
+			valueSpec := spec.(*ast.ValueSpec) // Must succeed; we can't mix types in one GenDecl.
+
+			// The type name may carry over from a previous specification in the
+			// case of constants and iota.
+			if valueSpec.Type != nil {
+				typ = fmt.Sprintf(" %s", pkg.oneLineNodeDepth(valueSpec.Type, depth))
+			} else if len(valueSpec.Values) > 0 {
+				typ = ""
+			}
+
+			if !isExported(valueSpec.Names[0].Name) {
+				continue
+			}
+			val := ""
+			if i < len(valueSpec.Values) && valueSpec.Values[i] != nil {
+				val = fmt.Sprintf(" = %s", pkg.oneLineNodeDepth(valueSpec.Values[i], depth))
+			}
+			return fmt.Sprintf("%s %s%s%s%s", n.Tok, valueSpec.Names[0], typ, val, trailer)
+		}
+		return ""
+
+	case *ast.FuncDecl:
+		// Formats func declarations.
+		name := n.Name.Name
+		recv := pkg.oneLineNodeDepth(n.Recv, depth)
+		if len(recv) > 0 {
+			recv = "(" + recv + ") "
+		}
+		fnc := pkg.oneLineNodeDepth(n.Type, depth)
+		if strings.Index(fnc, "func") == 0 {
+			fnc = fnc[4:]
+		}
+		return fmt.Sprintf("func %s%s%s", recv, name, fnc)
+
+	case *ast.TypeSpec:
+		sep := " "
+		if n.Assign.IsValid() {
+			sep = " = "
+		}
+		return fmt.Sprintf("type %s%s%s", n.Name.Name, sep, pkg.oneLineNodeDepth(n.Type, depth))
+
+	case *ast.FuncType:
+		var params []string
+		if n.Params != nil {
+			for _, field := range n.Params.List {
+				params = append(params, pkg.oneLineField(field, depth))
+			}
+		}
+		needParens := false
+		var results []string
+		if n.Results != nil {
+			needParens = needParens || len(n.Results.List) > 1
+			for _, field := range n.Results.List {
+				needParens = needParens || len(field.Names) > 0
+				results = append(results, pkg.oneLineField(field, depth))
+			}
+		}
+
+		param := joinStrings(params)
+		if len(results) == 0 {
+			return fmt.Sprintf("func(%s)", param)
+		}
+		result := joinStrings(results)
+		if !needParens {
+			return fmt.Sprintf("func(%s) %s", param, result)
+		}
+		return fmt.Sprintf("func(%s) (%s)", param, result)
+
+	case *ast.StructType:
+		if n.Fields == nil || len(n.Fields.List) == 0 {
+			return "struct{}"
+		}
+		return "struct{ ... }"
+
+	case *ast.InterfaceType:
+		if n.Methods == nil || len(n.Methods.List) == 0 {
+			return "interface{}"
+		}
+		return "interface{ ... }"
+
+	case *ast.FieldList:
+		if n == nil || len(n.List) == 0 {
+			return ""
+		}
+		if len(n.List) == 1 {
+			return pkg.oneLineField(n.List[0], depth)
+		}
+		return dotDotDot
+
+	case *ast.FuncLit:
+		return pkg.oneLineNodeDepth(n.Type, depth) + " { ... }"
+
+	case *ast.CompositeLit:
+		typ := pkg.oneLineNodeDepth(n.Type, depth)
+		if len(n.Elts) == 0 {
+			return fmt.Sprintf("%s{}", typ)
+		}
+		return fmt.Sprintf("%s{ %s }", typ, dotDotDot)
+
+	case *ast.ArrayType:
+		length := pkg.oneLineNodeDepth(n.Len, depth)
+		element := pkg.oneLineNodeDepth(n.Elt, depth)
+		return fmt.Sprintf("[%s]%s", length, element)
+
+	case *ast.MapType:
+		key := pkg.oneLineNodeDepth(n.Key, depth)
+		value := pkg.oneLineNodeDepth(n.Value, depth)
+		return fmt.Sprintf("map[%s]%s", key, value)
+
+	case *ast.CallExpr:
+		fnc := pkg.oneLineNodeDepth(n.Fun, depth)
+		var args []string
+		for _, arg := range n.Args {
+			args = append(args, pkg.oneLineNodeDepth(arg, depth))
+		}
+		return fmt.Sprintf("%s(%s)", fnc, joinStrings(args))
+
+	case *ast.UnaryExpr:
+		return fmt.Sprintf("%s%s", n.Op, pkg.oneLineNodeDepth(n.X, depth))
+
+	case *ast.Ident:
+		return n.Name
+
+	default:
+		// As a fallback, use default formatter for all unknown node types.
+		buf := new(bytes.Buffer)
+		format.Node(buf, pkg.fs, node)
+		s := buf.String()
+		if strings.Contains(s, "\n") {
+			return dotDotDot
+		}
+		return s
+	}
+}
+
+// oneLineField returns a one-line summary of the field.
+func (pkg *Package) oneLineField(field *ast.Field, depth int) string {
+	var names []string
+	for _, name := range field.Names {
+		names = append(names, name.Name)
+	}
+	if len(names) == 0 {
+		return pkg.oneLineNodeDepth(field.Type, depth)
+	}
+	return joinStrings(names) + " " + pkg.oneLineNodeDepth(field.Type, depth)
+}
+
+// joinStrings formats the input as a comma-separated list,
+// but truncates the list at some reasonable length if necessary.
+func joinStrings(ss []string) string {
+	var n int
+	for i, s := range ss {
+		n += len(s) + len(", ")
+		if n > punchedCardWidth {
+			ss = append(ss[:i:i], "...")
+			break
+		}
+	}
+	return strings.Join(ss, ", ")
+}
+
+// allDoc prints all the docs for the package.
+func (pkg *Package) allDoc() {
+	pkg.Printf("") // Trigger the package clause; we know the package exists.
+	doc.ToText(&pkg.buf, pkg.doc.Doc, "", indent, indentedWidth)
+	pkg.newlines(1)
+
+	printed := make(map[*ast.GenDecl]bool)
+
+	hdr := ""
+	printHdr := func(s string) {
+		if hdr != s {
+			pkg.Printf("\n%s\n\n", s)
+			hdr = s
+		}
+	}
+
+	// Constants.
+	for _, value := range pkg.doc.Consts {
+		// Constants and variables come in groups, and valueDoc prints
+		// all the items in the group. We only need to find one exported symbol.
+		for _, name := range value.Names {
+			if isExported(name) && !pkg.typedValue[value] {
+				printHdr("CONSTANTS")
+				pkg.valueDoc(value, printed)
+				break
+			}
+		}
+	}
+
+	// Variables.
+	for _, value := range pkg.doc.Vars {
+		// Constants and variables come in groups, and valueDoc prints
+		// all the items in the group. We only need to find one exported symbol.
+		for _, name := range value.Names {
+			if isExported(name) && !pkg.typedValue[value] {
+				printHdr("VARIABLES")
+				pkg.valueDoc(value, printed)
+				break
+			}
+		}
+	}
+
+	// Functions.
+	for _, fun := range pkg.doc.Funcs {
+		if isExported(fun.Name) && !pkg.constructor[fun] {
+			printHdr("FUNCTIONS")
+			pkg.emit(fun.Doc, fun.Decl)
+		}
+	}
+
+	// Types.
+	for _, typ := range pkg.doc.Types {
+		if isExported(typ.Name) {
+			printHdr("TYPES")
+			pkg.typeDoc(typ)
+		}
+	}
+}
+
+// packageDoc prints the docs for the package (package doc plus one-liners of the rest).
+func (pkg *Package) packageDoc() {
+	pkg.Printf("") // Trigger the package clause; we know the package exists.
+	if !short {
+		doc.ToText(&pkg.buf, pkg.doc.Doc, "", indent, indentedWidth)
+		pkg.newlines(1)
+	}
+
+	if pkg.pkg.Name == "main" && !showCmd {
+		// Show only package docs for commands.
+		return
+	}
+
+	if !short {
+		pkg.newlines(2) // Guarantee blank line before the components.
+	}
+
+	pkg.valueSummary(pkg.doc.Consts, false)
+	pkg.valueSummary(pkg.doc.Vars, false)
+	pkg.funcSummary(pkg.doc.Funcs, false)
+	pkg.typeSummary()
+	if !short {
+		pkg.bugs()
+	}
+}
+
+// packageClause prints the package clause.
+func (pkg *Package) packageClause() {
+	if short {
+		return
+	}
+	importPath := pkg.build.ImportComment
+	if importPath == "" {
+		importPath = pkg.build.ImportPath
+	}
+
+	// If we're using modules, the import path derived from module code locations wins.
+	// If we did a file system scan, we knew the import path when we found the directory.
+	// But if we started with a directory name, we never knew the import path.
+	// Either way, we don't know it now, and it's cheap to (re)compute it.
+	if usingModules {
+		for _, root := range codeRoots() {
+			if pkg.build.Dir == root.dir {
+				importPath = root.importPath
+				break
+			}
+			if strings.HasPrefix(pkg.build.Dir, root.dir+string(filepath.Separator)) {
+				suffix := filepath.ToSlash(pkg.build.Dir[len(root.dir)+1:])
+				if root.importPath == "" {
+					importPath = suffix
+				} else {
+					importPath = root.importPath + "/" + suffix
+				}
+				break
+			}
+		}
+	}
+
+	pkg.Printf("package %s // import %q\n\n", pkg.name, importPath)
+	if !usingModules && importPath != pkg.build.ImportPath {
+		pkg.Printf("WARNING: package source is installed in %q\n", pkg.build.ImportPath)
+	}
+}
+
+// valueSummary prints a one-line summary for each set of values and constants.
+// If all the types in a constant or variable declaration belong to the same
+// type they can be printed by typeSummary, and so can be suppressed here.
+func (pkg *Package) valueSummary(values []*doc.Value, showGrouped bool) {
+	var isGrouped map[*doc.Value]bool
+	if !showGrouped {
+		isGrouped = make(map[*doc.Value]bool)
+		for _, typ := range pkg.doc.Types {
+			if !isExported(typ.Name) {
+				continue
+			}
+			for _, c := range typ.Consts {
+				isGrouped[c] = true
+			}
+			for _, v := range typ.Vars {
+				isGrouped[v] = true
+			}
+		}
+	}
+
+	for _, value := range values {
+		if !isGrouped[value] {
+			if decl := pkg.oneLineNode(value.Decl); decl != "" {
+				pkg.Printf("%s\n", decl)
+			}
+		}
+	}
+}
+
+// funcSummary prints a one-line summary for each function. Constructors
+// are printed by typeSummary, below, and so can be suppressed here.
+func (pkg *Package) funcSummary(funcs []*doc.Func, showConstructors bool) {
+	for _, fun := range funcs {
+		// Exported functions only. The go/doc package does not include methods here.
+		if isExported(fun.Name) {
+			if showConstructors || !pkg.constructor[fun] {
+				pkg.Printf("%s\n", pkg.oneLineNode(fun.Decl))
+			}
+		}
+	}
+}
+
+// typeSummary prints a one-line summary for each type, followed by its constructors.
+func (pkg *Package) typeSummary() {
+	for _, typ := range pkg.doc.Types {
+		for _, spec := range typ.Decl.Specs {
+			typeSpec := spec.(*ast.TypeSpec) // Must succeed.
+			if isExported(typeSpec.Name.Name) {
+				pkg.Printf("%s\n", pkg.oneLineNode(typeSpec))
+				// Now print the consts, vars, and constructors.
+				for _, c := range typ.Consts {
+					if decl := pkg.oneLineNode(c.Decl); decl != "" {
+						pkg.Printf(indent+"%s\n", decl)
+					}
+				}
+				for _, v := range typ.Vars {
+					if decl := pkg.oneLineNode(v.Decl); decl != "" {
+						pkg.Printf(indent+"%s\n", decl)
+					}
+				}
+				for _, constructor := range typ.Funcs {
+					if isExported(constructor.Name) {
+						pkg.Printf(indent+"%s\n", pkg.oneLineNode(constructor.Decl))
+					}
+				}
+			}
+		}
+	}
+}
+
+// bugs prints the BUGS information for the package.
+// TODO: Provide access to TODOs and NOTEs as well (very noisy so off by default)?
+func (pkg *Package) bugs() {
+	if pkg.doc.Notes["BUG"] == nil {
+		return
+	}
+	pkg.Printf("\n")
+	for _, note := range pkg.doc.Notes["BUG"] {
+		pkg.Printf("%s: %v\n", "BUG", note.Body)
+	}
+}
+
+// findValues finds the doc.Values that describe the symbol.
+func (pkg *Package) findValues(symbol string, docValues []*doc.Value) (values []*doc.Value) {
+	for _, value := range docValues {
+		for _, name := range value.Names {
+			if match(symbol, name) {
+				values = append(values, value)
+			}
+		}
+	}
+	return
+}
+
+// findFuncs finds the doc.Funcs that describes the symbol.
+func (pkg *Package) findFuncs(symbol string) (funcs []*doc.Func) {
+	for _, fun := range pkg.doc.Funcs {
+		if match(symbol, fun.Name) {
+			funcs = append(funcs, fun)
+		}
+	}
+	return
+}
+
+// findTypes finds the doc.Types that describes the symbol.
+// If symbol is empty, it finds all exported types.
+func (pkg *Package) findTypes(symbol string) (types []*doc.Type) {
+	for _, typ := range pkg.doc.Types {
+		if symbol == "" && isExported(typ.Name) || match(symbol, typ.Name) {
+			types = append(types, typ)
+		}
+	}
+	return
+}
+
+// findTypeSpec returns the ast.TypeSpec within the declaration that defines the symbol.
+// The name must match exactly.
+func (pkg *Package) findTypeSpec(decl *ast.GenDecl, symbol string) *ast.TypeSpec {
+	for _, spec := range decl.Specs {
+		typeSpec := spec.(*ast.TypeSpec) // Must succeed.
+		if symbol == typeSpec.Name.Name {
+			return typeSpec
+		}
+	}
+	return nil
+}
+
+// symbolDoc prints the docs for symbol. There may be multiple matches.
+// If symbol matches a type, output includes its methods factories and associated constants.
+// If there is no top-level symbol, symbolDoc looks for methods that match.
+func (pkg *Package) symbolDoc(symbol string) bool {
+	found := false
+	// Functions.
+	for _, fun := range pkg.findFuncs(symbol) {
+		// Symbol is a function.
+		decl := fun.Decl
+		pkg.emit(fun.Doc, decl)
+		found = true
+	}
+	// Constants and variables behave the same.
+	values := pkg.findValues(symbol, pkg.doc.Consts)
+	values = append(values, pkg.findValues(symbol, pkg.doc.Vars)...)
+	// A declaration like
+	//	const ( c = 1; C = 2 )
+	// could be printed twice if the -u flag is set, as it matches twice.
+	// So we remember which declarations we've printed to avoid duplication.
+	printed := make(map[*ast.GenDecl]bool)
+	for _, value := range values {
+		pkg.valueDoc(value, printed)
+		found = true
+	}
+	// Types.
+	for _, typ := range pkg.findTypes(symbol) {
+		pkg.typeDoc(typ)
+		found = true
+	}
+	if !found {
+		// See if there are methods.
+		if !pkg.printMethodDoc("", symbol) {
+			return false
+		}
+	}
+	return true
+}
+
+// valueDoc prints the docs for a constant or variable.
+func (pkg *Package) valueDoc(value *doc.Value, printed map[*ast.GenDecl]bool) {
+	if printed[value.Decl] {
+		return
+	}
+	// Print each spec only if there is at least one exported symbol in it.
+	// (See issue 11008.)
+	// TODO: Should we elide unexported symbols from a single spec?
+	// It's an unlikely scenario, probably not worth the trouble.
+	// TODO: Would be nice if go/doc did this for us.
+	specs := make([]ast.Spec, 0, len(value.Decl.Specs))
+	var typ ast.Expr
+	for _, spec := range value.Decl.Specs {
+		vspec := spec.(*ast.ValueSpec)
+
+		// The type name may carry over from a previous specification in the
+		// case of constants and iota.
+		if vspec.Type != nil {
+			typ = vspec.Type
+		}
+
+		for _, ident := range vspec.Names {
+			if showSrc || isExported(ident.Name) {
+				if vspec.Type == nil && vspec.Values == nil && typ != nil {
+					// This a standalone identifier, as in the case of iota usage.
+					// Thus, assume the type comes from the previous type.
+					vspec.Type = &ast.Ident{
+						Name:    pkg.oneLineNode(typ),
+						NamePos: vspec.End() - 1,
+					}
+				}
+
+				specs = append(specs, vspec)
+				typ = nil // Only inject type on first exported identifier
+				break
+			}
+		}
+	}
+	if len(specs) == 0 {
+		return
+	}
+	value.Decl.Specs = specs
+	pkg.emit(value.Doc, value.Decl)
+	printed[value.Decl] = true
+}
+
+// typeDoc prints the docs for a type, including constructors and other items
+// related to it.
+func (pkg *Package) typeDoc(typ *doc.Type) {
+	decl := typ.Decl
+	spec := pkg.findTypeSpec(decl, typ.Name)
+	trimUnexportedElems(spec)
+	// If there are multiple types defined, reduce to just this one.
+	if len(decl.Specs) > 1 {
+		decl.Specs = []ast.Spec{spec}
+	}
+	pkg.emit(typ.Doc, decl)
+	pkg.newlines(2)
+	// Show associated methods, constants, etc.
+	if showAll {
+		printed := make(map[*ast.GenDecl]bool)
+		// We can use append here to print consts, then vars. Ditto for funcs and methods.
+		values := typ.Consts
+		values = append(values, typ.Vars...)
+		for _, value := range values {
+			for _, name := range value.Names {
+				if isExported(name) {
+					pkg.valueDoc(value, printed)
+					break
+				}
+			}
+		}
+		funcs := typ.Funcs
+		funcs = append(funcs, typ.Methods...)
+		for _, fun := range funcs {
+			if isExported(fun.Name) {
+				pkg.emit(fun.Doc, fun.Decl)
+				if fun.Doc == "" {
+					pkg.newlines(2)
+				}
+			}
+		}
+	} else {
+		pkg.valueSummary(typ.Consts, true)
+		pkg.valueSummary(typ.Vars, true)
+		pkg.funcSummary(typ.Funcs, true)
+		pkg.funcSummary(typ.Methods, true)
+	}
+}
+
+// trimUnexportedElems modifies spec in place to elide unexported fields from
+// structs and methods from interfaces (unless the unexported flag is set or we
+// are asked to show the original source).
+func trimUnexportedElems(spec *ast.TypeSpec) {
+	if unexported || showSrc {
+		return
+	}
+	switch typ := spec.Type.(type) {
+	case *ast.StructType:
+		typ.Fields = trimUnexportedFields(typ.Fields, false)
+	case *ast.InterfaceType:
+		typ.Methods = trimUnexportedFields(typ.Methods, true)
+	}
+}
+
+// trimUnexportedFields returns the field list trimmed of unexported fields.
+func trimUnexportedFields(fields *ast.FieldList, isInterface bool) *ast.FieldList {
+	what := "methods"
+	if !isInterface {
+		what = "fields"
+	}
+
+	trimmed := false
+	list := make([]*ast.Field, 0, len(fields.List))
+	for _, field := range fields.List {
+		names := field.Names
+		if len(names) == 0 {
+			// Embedded type. Use the name of the type. It must be of the form ident or
+			// pkg.ident (for structs and interfaces), or *ident or *pkg.ident (structs only).
+			// Nothing else is allowed.
+			ty := field.Type
+			if se, ok := field.Type.(*ast.StarExpr); !isInterface && ok {
+				// The form *ident or *pkg.ident is only valid on
+				// embedded types in structs.
+				ty = se.X
+			}
+			switch ident := ty.(type) {
+			case *ast.Ident:
+				if isInterface && ident.Name == "error" && ident.Obj == nil {
+					// For documentation purposes, we consider the builtin error
+					// type special when embedded in an interface, such that it
+					// always gets shown publicly.
+					list = append(list, field)
+					continue
+				}
+				names = []*ast.Ident{ident}
+			case *ast.SelectorExpr:
+				// An embedded type may refer to a type in another package.
+				names = []*ast.Ident{ident.Sel}
+			}
+			if names == nil {
+				// Can only happen if AST is incorrect. Safe to continue with a nil list.
+				log.Print("invalid program: unexpected type for embedded field")
+			}
+		}
+		// Trims if any is unexported. Good enough in practice.
+		ok := true
+		for _, name := range names {
+			if !isExported(name.Name) {
+				trimmed = true
+				ok = false
+				break
+			}
+		}
+		if ok {
+			list = append(list, field)
+		}
+	}
+	if !trimmed {
+		return fields
+	}
+	unexportedField := &ast.Field{
+		Type: &ast.Ident{
+			// Hack: printer will treat this as a field with a named type.
+			// Setting Name and NamePos to ("", fields.Closing-1) ensures that
+			// when Pos and End are called on this field, they return the
+			// position right before closing '}' character.
+			Name:    "",
+			NamePos: fields.Closing - 1,
+		},
+		Comment: &ast.CommentGroup{
+			List: []*ast.Comment{{Text: fmt.Sprintf("// Has unexported %s.\n", what)}},
+		},
+	}
+	return &ast.FieldList{
+		Opening: fields.Opening,
+		List:    append(list, unexportedField),
+		Closing: fields.Closing,
+	}
+}
+
+// printMethodDoc prints the docs for matches of symbol.method.
+// If symbol is empty, it prints all methods for any concrete type
+// that match the name. It reports whether it found any methods.
+func (pkg *Package) printMethodDoc(symbol, method string) bool {
+	types := pkg.findTypes(symbol)
+	if types == nil {
+		if symbol == "" {
+			return false
+		}
+		pkg.Fatalf("symbol %s is not a type in package %s installed in %q", symbol, pkg.name, pkg.build.ImportPath)
+	}
+	found := false
+	for _, typ := range types {
+		if len(typ.Methods) > 0 {
+			for _, meth := range typ.Methods {
+				if match(method, meth.Name) {
+					decl := meth.Decl
+					pkg.emit(meth.Doc, decl)
+					found = true
+				}
+			}
+			continue
+		}
+		if symbol == "" {
+			continue
+		}
+		// Type may be an interface. The go/doc package does not attach
+		// an interface's methods to the doc.Type. We need to dig around.
+		spec := pkg.findTypeSpec(typ.Decl, typ.Name)
+		inter, ok := spec.Type.(*ast.InterfaceType)
+		if !ok {
+			// Not an interface type.
+			continue
+		}
+		for _, iMethod := range inter.Methods.List {
+			// This is an interface, so there can be only one name.
+			// TODO: Anonymous methods (embedding)
+			if len(iMethod.Names) == 0 {
+				continue
+			}
+			name := iMethod.Names[0].Name
+			if match(method, name) {
+				if iMethod.Doc != nil {
+					for _, comment := range iMethod.Doc.List {
+						doc.ToText(&pkg.buf, comment.Text, "", indent, indentedWidth)
+					}
+				}
+				s := pkg.oneLineNode(iMethod.Type)
+				// Hack: s starts "func" but there is no name present.
+				// We could instead build a FuncDecl but it's not worthwhile.
+				lineComment := ""
+				if iMethod.Comment != nil {
+					lineComment = fmt.Sprintf("  %s", iMethod.Comment.List[0].Text)
+				}
+				pkg.Printf("func %s%s%s\n", name, s[4:], lineComment)
+				found = true
+			}
+		}
+	}
+	return found
+}
+
+// printFieldDoc prints the docs for matches of symbol.fieldName.
+// It reports whether it found any field.
+// Both symbol and fieldName must be non-empty or it returns false.
+func (pkg *Package) printFieldDoc(symbol, fieldName string) bool {
+	if symbol == "" || fieldName == "" {
+		return false
+	}
+	types := pkg.findTypes(symbol)
+	if types == nil {
+		pkg.Fatalf("symbol %s is not a type in package %s installed in %q", symbol, pkg.name, pkg.build.ImportPath)
+	}
+	found := false
+	numUnmatched := 0
+	for _, typ := range types {
+		// Type must be a struct.
+		spec := pkg.findTypeSpec(typ.Decl, typ.Name)
+		structType, ok := spec.Type.(*ast.StructType)
+		if !ok {
+			// Not a struct type.
+			continue
+		}
+		for _, field := range structType.Fields.List {
+			// TODO: Anonymous fields.
+			for _, name := range field.Names {
+				if !match(fieldName, name.Name) {
+					numUnmatched++
+					continue
+				}
+				if !found {
+					pkg.Printf("type %s struct {\n", typ.Name)
+				}
+				if field.Doc != nil {
+					// To present indented blocks in comments correctly, process the comment as
+					// a unit before adding the leading // to each line.
+					docBuf := bytes.Buffer{}
+					doc.ToText(&docBuf, field.Doc.Text(), "", indent, indentedWidth)
+					scanner := bufio.NewScanner(&docBuf)
+					for scanner.Scan() {
+						fmt.Fprintf(&pkg.buf, "%s// %s\n", indent, scanner.Bytes())
+					}
+				}
+				s := pkg.oneLineNode(field.Type)
+				lineComment := ""
+				if field.Comment != nil {
+					lineComment = fmt.Sprintf("  %s", field.Comment.List[0].Text)
+				}
+				pkg.Printf("%s%s %s%s\n", indent, name, s, lineComment)
+				found = true
+			}
+		}
+	}
+	if found {
+		if numUnmatched > 0 {
+			pkg.Printf("\n    // ... other fields elided ...\n")
+		}
+		pkg.Printf("}\n")
+	}
+	return found
+}
+
+// methodDoc prints the docs for matches of symbol.method.
+func (pkg *Package) methodDoc(symbol, method string) bool {
+	return pkg.printMethodDoc(symbol, method)
+}
+
+// fieldDoc prints the docs for matches of symbol.field.
+func (pkg *Package) fieldDoc(symbol, field string) bool {
+	return pkg.printFieldDoc(symbol, field)
+}
+
+// match reports whether the user's symbol matches the program's.
+// A lower-case character in the user's string matches either case in the program's.
+// The program string must be exported.
+func match(user, program string) bool {
+	if !isExported(program) {
+		return false
+	}
+	if matchCase {
+		return user == program
+	}
+	for _, u := range user {
+		p, w := utf8.DecodeRuneInString(program)
+		program = program[w:]
+		if u == p {
+			continue
+		}
+		if unicode.IsLower(u) && simpleFold(u) == simpleFold(p) {
+			continue
+		}
+		return false
+	}
+	return program == ""
+}
+
+// simpleFold returns the minimum rune equivalent to r
+// under Unicode-defined simple case folding.
+func simpleFold(r rune) rune {
+	for {
+		r1 := unicode.SimpleFold(r)
+		if r1 <= r {
+			return r1 // wrapped around, found min
+		}
+		r = r1
+	}
+}