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// Copyright 2013 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 godoc is a work-in-progress (2013-07-17) package to
// begin splitting up the godoc binary into multiple pieces.
//
// This package comment will evolve over time as this package splits
// into smaller pieces.
package godoc // import "golang.org/x/tools/godoc"
import (
"bufio"
"bytes"
"fmt"
"go/ast"
"go/doc"
"go/format"
"go/printer"
"go/token"
htmltemplate "html/template"
"io"
"log"
"os"
pathpkg "path"
"regexp"
"strconv"
"strings"
"text/template"
"time"
"unicode"
"unicode/utf8"
)
// Fake relative package path for built-ins. Documentation for all globals
// (not just exported ones) will be shown for packages in this directory.
const builtinPkgPath = "builtin"
// FuncMap defines template functions used in godoc templates.
//
// Convention: template function names ending in "_html" or "_url" produce
// HTML- or URL-escaped strings; all other function results may
// require explicit escaping in the template.
func (p *Presentation) FuncMap() template.FuncMap {
p.initFuncMapOnce.Do(p.initFuncMap)
return p.funcMap
}
func (p *Presentation) TemplateFuncs() template.FuncMap {
p.initFuncMapOnce.Do(p.initFuncMap)
return p.templateFuncs
}
func (p *Presentation) initFuncMap() {
if p.Corpus == nil {
panic("nil Presentation.Corpus")
}
p.templateFuncs = template.FuncMap{
"code": p.code,
}
p.funcMap = template.FuncMap{
// various helpers
"filename": filenameFunc,
"repeat": strings.Repeat,
"since": p.Corpus.pkgAPIInfo.sinceVersionFunc,
// access to FileInfos (directory listings)
"fileInfoName": fileInfoNameFunc,
"fileInfoTime": fileInfoTimeFunc,
// access to search result information
"infoKind_html": infoKind_htmlFunc,
"infoLine": p.infoLineFunc,
"infoSnippet_html": p.infoSnippet_htmlFunc,
// formatting of AST nodes
"node": p.nodeFunc,
"node_html": p.node_htmlFunc,
"comment_html": comment_htmlFunc,
"sanitize": sanitizeFunc,
// support for URL attributes
"pkgLink": pkgLinkFunc,
"srcLink": srcLinkFunc,
"posLink_url": newPosLink_urlFunc(srcPosLinkFunc),
"docLink": docLinkFunc,
"queryLink": queryLinkFunc,
"srcBreadcrumb": srcBreadcrumbFunc,
"srcToPkgLink": srcToPkgLinkFunc,
// formatting of Examples
"example_html": p.example_htmlFunc,
"example_name": p.example_nameFunc,
"example_suffix": p.example_suffixFunc,
// formatting of analysis information
"callgraph_html": p.callgraph_htmlFunc,
"implements_html": p.implements_htmlFunc,
"methodset_html": p.methodset_htmlFunc,
// formatting of Notes
"noteTitle": noteTitle,
// Number operation
"multiply": multiply,
// formatting of PageInfoMode query string
"modeQueryString": modeQueryString,
// check whether to display third party section or not
"hasThirdParty": hasThirdParty,
// get the no. of columns to split the toc in search page
"tocColCount": tocColCount,
}
if p.URLForSrc != nil {
p.funcMap["srcLink"] = p.URLForSrc
}
if p.URLForSrcPos != nil {
p.funcMap["posLink_url"] = newPosLink_urlFunc(p.URLForSrcPos)
}
if p.URLForSrcQuery != nil {
p.funcMap["queryLink"] = p.URLForSrcQuery
}
}
func multiply(a, b int) int { return a * b }
func filenameFunc(path string) string {
_, localname := pathpkg.Split(path)
return localname
}
func fileInfoNameFunc(fi os.FileInfo) string {
name := fi.Name()
if fi.IsDir() {
name += "/"
}
return name
}
func fileInfoTimeFunc(fi os.FileInfo) string {
if t := fi.ModTime(); t.Unix() != 0 {
return t.Local().String()
}
return "" // don't return epoch if time is obviously not set
}
// The strings in infoKinds must be properly html-escaped.
var infoKinds = [nKinds]string{
PackageClause: "package clause",
ImportDecl: "import decl",
ConstDecl: "const decl",
TypeDecl: "type decl",
VarDecl: "var decl",
FuncDecl: "func decl",
MethodDecl: "method decl",
Use: "use",
}
func infoKind_htmlFunc(info SpotInfo) string {
return infoKinds[info.Kind()] // infoKind entries are html-escaped
}
func (p *Presentation) infoLineFunc(info SpotInfo) int {
line := info.Lori()
if info.IsIndex() {
index, _ := p.Corpus.searchIndex.Get()
if index != nil {
line = index.(*Index).Snippet(line).Line
} else {
// no line information available because
// we don't have an index - this should
// never happen; be conservative and don't
// crash
line = 0
}
}
return line
}
func (p *Presentation) infoSnippet_htmlFunc(info SpotInfo) string {
if info.IsIndex() {
index, _ := p.Corpus.searchIndex.Get()
// Snippet.Text was HTML-escaped when it was generated
return index.(*Index).Snippet(info.Lori()).Text
}
return `<span class="alert">no snippet text available</span>`
}
func (p *Presentation) nodeFunc(info *PageInfo, node interface{}) string {
var buf bytes.Buffer
p.writeNode(&buf, info, info.FSet, node)
return buf.String()
}
func (p *Presentation) node_htmlFunc(info *PageInfo, node interface{}, linkify bool) string {
var buf1 bytes.Buffer
p.writeNode(&buf1, info, info.FSet, node)
var buf2 bytes.Buffer
if n, _ := node.(ast.Node); n != nil && linkify && p.DeclLinks {
LinkifyText(&buf2, buf1.Bytes(), n)
if st, name := isStructTypeDecl(n); st != nil {
addStructFieldIDAttributes(&buf2, name, st)
}
} else {
FormatText(&buf2, buf1.Bytes(), -1, true, "", nil)
}
return buf2.String()
}
// isStructTypeDecl checks whether n is a struct declaration.
// It either returns a non-nil StructType and its name, or zero values.
func isStructTypeDecl(n ast.Node) (st *ast.StructType, name string) {
gd, ok := n.(*ast.GenDecl)
if !ok || gd.Tok != token.TYPE {
return nil, ""
}
if gd.Lparen > 0 {
// Parenthesized type. Who does that, anyway?
// TODO: Reportedly gri does. Fix this to handle that too.
return nil, ""
}
if len(gd.Specs) != 1 {
return nil, ""
}
ts, ok := gd.Specs[0].(*ast.TypeSpec)
if !ok {
return nil, ""
}
st, ok = ts.Type.(*ast.StructType)
if !ok {
return nil, ""
}
return st, ts.Name.Name
}
// addStructFieldIDAttributes modifies the contents of buf such that
// all struct fields of the named struct have <span id='name.Field'>
// in them, so people can link to /#Struct.Field.
func addStructFieldIDAttributes(buf *bytes.Buffer, name string, st *ast.StructType) {
if st.Fields == nil {
return
}
// needsLink is a set of identifiers that still need to be
// linked, where value == key, to avoid an allocation in func
// linkedField.
needsLink := make(map[string]string)
for _, f := range st.Fields.List {
if len(f.Names) == 0 {
continue
}
fieldName := f.Names[0].Name
needsLink[fieldName] = fieldName
}
var newBuf bytes.Buffer
foreachLine(buf.Bytes(), func(line []byte) {
if fieldName := linkedField(line, needsLink); fieldName != "" {
fmt.Fprintf(&newBuf, `<span id="%s.%s"></span>`, name, fieldName)
delete(needsLink, fieldName)
}
newBuf.Write(line)
})
buf.Reset()
buf.Write(newBuf.Bytes())
}
// foreachLine calls fn for each line of in, where a line includes
// the trailing "\n", except on the last line, if it doesn't exist.
func foreachLine(in []byte, fn func(line []byte)) {
for len(in) > 0 {
nl := bytes.IndexByte(in, '\n')
if nl == -1 {
fn(in)
return
}
fn(in[:nl+1])
in = in[nl+1:]
}
}
// commentPrefix is the line prefix for comments after they've been HTMLified.
var commentPrefix = []byte(`<span class="comment">// `)
// linkedField determines whether the given line starts with an
// identifer in the provided ids map (mapping from identifier to the
// same identifier). The line can start with either an identifier or
// an identifier in a comment. If one matches, it returns the
// identifier that matched. Otherwise it returns the empty string.
func linkedField(line []byte, ids map[string]string) string {
line = bytes.TrimSpace(line)
// For fields with a doc string of the
// conventional form, we put the new span into
// the comment instead of the field.
// The "conventional" form is a complete sentence
// per https://golang.org/s/style#comment-sentences like:
//
// // Foo is an optional Fooer to foo the foos.
// Foo Fooer
//
// In this case, we want the #StructName.Foo
// link to make the browser go to the comment
// line "Foo is an optional Fooer" instead of
// the "Foo Fooer" line, which could otherwise
// obscure the docs above the browser's "fold".
//
// TODO: do this better, so it works for all
// comments, including unconventional ones.
if bytes.HasPrefix(line, commentPrefix) {
line = line[len(commentPrefix):]
}
id := scanIdentifier(line)
if len(id) == 0 {
// No leading identifier. Avoid map lookup for
// somewhat common case.
return ""
}
return ids[string(id)]
}
// scanIdentifier scans a valid Go identifier off the front of v and
// either returns a subslice of v if there's a valid identifier, or
// returns a zero-length slice.
func scanIdentifier(v []byte) []byte {
var n int // number of leading bytes of v belonging to an identifier
for {
r, width := utf8.DecodeRune(v[n:])
if !(isLetter(r) || n > 0 && isDigit(r)) {
break
}
n += width
}
return v[:n]
}
func isLetter(ch rune) bool {
return 'a' <= ch && ch <= 'z' || 'A' <= ch && ch <= 'Z' || ch == '_' || ch >= utf8.RuneSelf && unicode.IsLetter(ch)
}
func isDigit(ch rune) bool {
return '0' <= ch && ch <= '9' || ch >= utf8.RuneSelf && unicode.IsDigit(ch)
}
func comment_htmlFunc(comment string) string {
var buf bytes.Buffer
// TODO(gri) Provide list of words (e.g. function parameters)
// to be emphasized by ToHTML.
doc.ToHTML(&buf, comment, nil) // does html-escaping
return buf.String()
}
// punchCardWidth is the number of columns of fixed-width
// characters to assume when wrapping text. Very few people
// use terminals or cards smaller than 80 characters, so 80 it is.
// We do not try to sniff the environment or the tty to adapt to
// the situation; instead, by using a constant we make sure that
// godoc always produces the same output regardless of context,
// a consistency that is lost otherwise. For example, if we sniffed
// the environment or tty, then http://golang.org/pkg/math/?m=text
// would depend on the width of the terminal where godoc started,
// which is clearly bogus. More generally, the Unix tools that behave
// differently when writing to a tty than when writing to a file have
// a history of causing confusion (compare `ls` and `ls | cat`), and we
// want to avoid that mistake here.
const punchCardWidth = 80
func containsOnlySpace(buf []byte) bool {
isNotSpace := func(r rune) bool { return !unicode.IsSpace(r) }
return bytes.IndexFunc(buf, isNotSpace) == -1
}
// sanitizeFunc sanitizes the argument src by replacing newlines with
// blanks, removing extra blanks, and by removing trailing whitespace
// and commas before closing parentheses.
func sanitizeFunc(src string) string {
buf := make([]byte, len(src))
j := 0 // buf index
comma := -1 // comma index if >= 0
for i := 0; i < len(src); i++ {
ch := src[i]
switch ch {
case '\t', '\n', ' ':
// ignore whitespace at the beginning, after a blank, or after opening parentheses
if j == 0 {
continue
}
if p := buf[j-1]; p == ' ' || p == '(' || p == '{' || p == '[' {
continue
}
// replace all whitespace with blanks
ch = ' '
case ',':
comma = j
case ')', '}', ']':
// remove any trailing comma
if comma >= 0 {
j = comma
}
// remove any trailing whitespace
if j > 0 && buf[j-1] == ' ' {
j--
}
default:
comma = -1
}
buf[j] = ch
j++
}
// remove trailing blank, if any
if j > 0 && buf[j-1] == ' ' {
j--
}
return string(buf[:j])
}
type PageInfo struct {
Dirname string // directory containing the package
Err error // error or nil
GoogleCN bool // page is being served from golang.google.cn
Mode PageInfoMode // display metadata from query string
// package info
FSet *token.FileSet // nil if no package documentation
PDoc *doc.Package // nil if no package documentation
Examples []*doc.Example // nil if no example code
Notes map[string][]*doc.Note // nil if no package Notes
PAst map[string]*ast.File // nil if no AST with package exports
IsMain bool // true for package main
IsFiltered bool // true if results were filtered
// analysis info
TypeInfoIndex map[string]int // index of JSON datum for type T (if -analysis=type)
AnalysisData htmltemplate.JS // array of TypeInfoJSON values
CallGraph htmltemplate.JS // array of PCGNodeJSON values (if -analysis=pointer)
CallGraphIndex map[string]int // maps func name to index in CallGraph
// directory info
Dirs *DirList // nil if no directory information
DirTime time.Time // directory time stamp
DirFlat bool // if set, show directory in a flat (non-indented) manner
}
func (info *PageInfo) IsEmpty() bool {
return info.Err != nil || info.PAst == nil && info.PDoc == nil && info.Dirs == nil
}
func pkgLinkFunc(path string) string {
// because of the irregular mapping under goroot
// we need to correct certain relative paths
path = strings.TrimPrefix(path, "/")
path = strings.TrimPrefix(path, "src/")
path = strings.TrimPrefix(path, "pkg/")
return "pkg/" + path
}
// srcToPkgLinkFunc builds an <a> tag linking to the package
// documentation of relpath.
func srcToPkgLinkFunc(relpath string) string {
relpath = pkgLinkFunc(relpath)
relpath = pathpkg.Dir(relpath)
if relpath == "pkg" {
return `<a href="/pkg">Index</a>`
}
return fmt.Sprintf(`<a href="/%s">%s</a>`, relpath, relpath[len("pkg/"):])
}
// srcBreadcrumbFun converts each segment of relpath to a HTML <a>.
// Each segment links to its corresponding src directories.
func srcBreadcrumbFunc(relpath string) string {
segments := strings.Split(relpath, "/")
var buf bytes.Buffer
var selectedSegment string
var selectedIndex int
if strings.HasSuffix(relpath, "/") {
// relpath is a directory ending with a "/".
// Selected segment is the segment before the last slash.
selectedIndex = len(segments) - 2
selectedSegment = segments[selectedIndex] + "/"
} else {
selectedIndex = len(segments) - 1
selectedSegment = segments[selectedIndex]
}
for i := range segments[:selectedIndex] {
buf.WriteString(fmt.Sprintf(`<a href="/%s">%s</a>/`,
strings.Join(segments[:i+1], "/"),
segments[i],
))
}
buf.WriteString(`<span class="text-muted">`)
buf.WriteString(selectedSegment)
buf.WriteString(`</span>`)
return buf.String()
}
func newPosLink_urlFunc(srcPosLinkFunc func(s string, line, low, high int) string) func(info *PageInfo, n interface{}) string {
// n must be an ast.Node or a *doc.Note
return func(info *PageInfo, n interface{}) string {
var pos, end token.Pos
switch n := n.(type) {
case ast.Node:
pos = n.Pos()
end = n.End()
case *doc.Note:
pos = n.Pos
end = n.End
default:
panic(fmt.Sprintf("wrong type for posLink_url template formatter: %T", n))
}
var relpath string
var line int
var low, high int // selection offset range
if pos.IsValid() {
p := info.FSet.Position(pos)
relpath = p.Filename
line = p.Line
low = p.Offset
}
if end.IsValid() {
high = info.FSet.Position(end).Offset
}
return srcPosLinkFunc(relpath, line, low, high)
}
}
func srcPosLinkFunc(s string, line, low, high int) string {
s = srcLinkFunc(s)
var buf bytes.Buffer
template.HTMLEscape(&buf, []byte(s))
// selection ranges are of form "s=low:high"
if low < high {
fmt.Fprintf(&buf, "?s=%d:%d", low, high) // no need for URL escaping
// if we have a selection, position the page
// such that the selection is a bit below the top
line -= 10
if line < 1 {
line = 1
}
}
// line id's in html-printed source are of the
// form "L%d" where %d stands for the line number
if line > 0 {
fmt.Fprintf(&buf, "#L%d", line) // no need for URL escaping
}
return buf.String()
}
func srcLinkFunc(s string) string {
s = pathpkg.Clean("/" + s)
if !strings.HasPrefix(s, "/src/") {
s = "/src" + s
}
return s
}
// queryLinkFunc returns a URL for a line in a source file with a highlighted
// query term.
// s is expected to be a path to a source file.
// query is expected to be a string that has already been appropriately escaped
// for use in a URL query.
func queryLinkFunc(s, query string, line int) string {
url := pathpkg.Clean("/"+s) + "?h=" + query
if line > 0 {
url += "#L" + strconv.Itoa(line)
}
return url
}
func docLinkFunc(s string, ident string) string {
return pathpkg.Clean("/pkg/"+s) + "/#" + ident
}
func (p *Presentation) example_htmlFunc(info *PageInfo, funcName string) string {
var buf bytes.Buffer
for _, eg := range info.Examples {
name := stripExampleSuffix(eg.Name)
if name != funcName {
continue
}
// print code
cnode := &printer.CommentedNode{Node: eg.Code, Comments: eg.Comments}
code := p.node_htmlFunc(info, cnode, true)
out := eg.Output
wholeFile := true
// Additional formatting if this is a function body.
if n := len(code); n >= 2 && code[0] == '{' && code[n-1] == '}' {
wholeFile = false
// remove surrounding braces
code = code[1 : n-1]
// unindent
code = replaceLeadingIndentation(code, strings.Repeat(" ", p.TabWidth), "")
// remove output comment
if loc := exampleOutputRx.FindStringIndex(code); loc != nil {
code = strings.TrimSpace(code[:loc[0]])
}
}
// Write out the playground code in standard Go style
// (use tabs, no comment highlight, etc).
play := ""
if eg.Play != nil && p.ShowPlayground {
var buf bytes.Buffer
eg.Play.Comments = filterOutBuildAnnotations(eg.Play.Comments)
if err := format.Node(&buf, info.FSet, eg.Play); err != nil {
log.Print(err)
} else {
play = buf.String()
}
}
// Drop output, as the output comment will appear in the code.
if wholeFile && play == "" {
out = ""
}
if p.ExampleHTML == nil {
out = ""
return ""
}
err := p.ExampleHTML.Execute(&buf, struct {
Name, Doc, Code, Play, Output string
GoogleCN bool
}{eg.Name, eg.Doc, code, play, out, info.GoogleCN})
if err != nil {
log.Print(err)
}
}
return buf.String()
}
func filterOutBuildAnnotations(cg []*ast.CommentGroup) []*ast.CommentGroup {
if len(cg) == 0 {
return cg
}
for i := range cg {
if !strings.HasPrefix(cg[i].Text(), "+build ") {
// Found the first non-build tag, return from here until the end
// of the slice.
return cg[i:]
}
}
// There weren't any non-build tags, return an empty slice.
return []*ast.CommentGroup{}
}
// example_nameFunc takes an example function name and returns its display
// name. For example, "Foo_Bar_quux" becomes "Foo.Bar (Quux)".
func (p *Presentation) example_nameFunc(s string) string {
name, suffix := splitExampleName(s)
// replace _ with . for method names
name = strings.Replace(name, "_", ".", 1)
// use "Package" if no name provided
if name == "" {
name = "Package"
}
return name + suffix
}
// example_suffixFunc takes an example function name and returns its suffix in
// parenthesized form. For example, "Foo_Bar_quux" becomes " (Quux)".
func (p *Presentation) example_suffixFunc(name string) string {
_, suffix := splitExampleName(name)
return suffix
}
// implements_html returns the "> Implements" toggle for a package-level named type.
// Its contents are populated from JSON data by client-side JS at load time.
func (p *Presentation) implements_htmlFunc(info *PageInfo, typeName string) string {
if p.ImplementsHTML == nil {
return ""
}
index, ok := info.TypeInfoIndex[typeName]
if !ok {
return ""
}
var buf bytes.Buffer
err := p.ImplementsHTML.Execute(&buf, struct{ Index int }{index})
if err != nil {
log.Print(err)
}
return buf.String()
}
// methodset_html returns the "> Method set" toggle for a package-level named type.
// Its contents are populated from JSON data by client-side JS at load time.
func (p *Presentation) methodset_htmlFunc(info *PageInfo, typeName string) string {
if p.MethodSetHTML == nil {
return ""
}
index, ok := info.TypeInfoIndex[typeName]
if !ok {
return ""
}
var buf bytes.Buffer
err := p.MethodSetHTML.Execute(&buf, struct{ Index int }{index})
if err != nil {
log.Print(err)
}
return buf.String()
}
// callgraph_html returns the "> Call graph" toggle for a package-level func.
// Its contents are populated from JSON data by client-side JS at load time.
func (p *Presentation) callgraph_htmlFunc(info *PageInfo, recv, name string) string {
if p.CallGraphHTML == nil {
return ""
}
if recv != "" {
// Format must match (*ssa.Function).RelString().
name = fmt.Sprintf("(%s).%s", recv, name)
}
index, ok := info.CallGraphIndex[name]
if !ok {
return ""
}
var buf bytes.Buffer
err := p.CallGraphHTML.Execute(&buf, struct{ Index int }{index})
if err != nil {
log.Print(err)
}
return buf.String()
}
func noteTitle(note string) string {
return strings.Title(strings.ToLower(note))
}
func startsWithUppercase(s string) bool {
r, _ := utf8.DecodeRuneInString(s)
return unicode.IsUpper(r)
}
var exampleOutputRx = regexp.MustCompile(`(?i)//[[:space:]]*(unordered )?output:`)
// stripExampleSuffix strips lowercase braz in Foo_braz or Foo_Bar_braz from name
// while keeping uppercase Braz in Foo_Braz.
func stripExampleSuffix(name string) string {
if i := strings.LastIndex(name, "_"); i != -1 {
if i < len(name)-1 && !startsWithUppercase(name[i+1:]) {
name = name[:i]
}
}
return name
}
func splitExampleName(s string) (name, suffix string) {
i := strings.LastIndex(s, "_")
if 0 <= i && i < len(s)-1 && !startsWithUppercase(s[i+1:]) {
name = s[:i]
suffix = " (" + strings.Title(s[i+1:]) + ")"
return
}
name = s
return
}
// replaceLeadingIndentation replaces oldIndent at the beginning of each line
// with newIndent. This is used for formatting examples. Raw strings that
// span multiple lines are handled specially: oldIndent is not removed (since
// go/printer will not add any indentation there), but newIndent is added
// (since we may still want leading indentation).
func replaceLeadingIndentation(body, oldIndent, newIndent string) string {
// Handle indent at the beginning of the first line. After this, we handle
// indentation only after a newline.
var buf bytes.Buffer
if strings.HasPrefix(body, oldIndent) {
buf.WriteString(newIndent)
body = body[len(oldIndent):]
}
// Use a state machine to keep track of whether we're in a string or
// rune literal while we process the rest of the code.
const (
codeState = iota
runeState
interpretedStringState
rawStringState
)
searchChars := []string{
"'\"`\n", // codeState
`\'`, // runeState
`\"`, // interpretedStringState
"`\n", // rawStringState
// newlineState does not need to search
}
state := codeState
for {
i := strings.IndexAny(body, searchChars[state])
if i < 0 {
buf.WriteString(body)
break
}
c := body[i]
buf.WriteString(body[:i+1])
body = body[i+1:]
switch state {
case codeState:
switch c {
case '\'':
state = runeState
case '"':
state = interpretedStringState
case '`':
state = rawStringState
case '\n':
if strings.HasPrefix(body, oldIndent) {
buf.WriteString(newIndent)
body = body[len(oldIndent):]
}
}
case runeState:
switch c {
case '\\':
r, size := utf8.DecodeRuneInString(body)
buf.WriteRune(r)
body = body[size:]
case '\'':
state = codeState
}
case interpretedStringState:
switch c {
case '\\':
r, size := utf8.DecodeRuneInString(body)
buf.WriteRune(r)
body = body[size:]
case '"':
state = codeState
}
case rawStringState:
switch c {
case '`':
state = codeState
case '\n':
buf.WriteString(newIndent)
}
}
}
return buf.String()
}
// writeNode writes the AST node x to w.
//
// The provided fset must be non-nil. The pageInfo is optional. If
// present, the pageInfo is used to add comments to struct fields to
// say which version of Go introduced them.
func (p *Presentation) writeNode(w io.Writer, pageInfo *PageInfo, fset *token.FileSet, x interface{}) {
// convert trailing tabs into spaces using a tconv filter
// to ensure a good outcome in most browsers (there may still
// be tabs in comments and strings, but converting those into
// the right number of spaces is much harder)
//
// TODO(gri) rethink printer flags - perhaps tconv can be eliminated
// with an another printer mode (which is more efficiently
// implemented in the printer than here with another layer)
var pkgName, structName string
var apiInfo pkgAPIVersions
if gd, ok := x.(*ast.GenDecl); ok && pageInfo != nil && pageInfo.PDoc != nil &&
p.Corpus != nil &&
gd.Tok == token.TYPE && len(gd.Specs) != 0 {
pkgName = pageInfo.PDoc.ImportPath
if ts, ok := gd.Specs[0].(*ast.TypeSpec); ok {
if _, ok := ts.Type.(*ast.StructType); ok {
structName = ts.Name.Name
}
}
apiInfo = p.Corpus.pkgAPIInfo[pkgName]
}
var out = w
var buf bytes.Buffer
if structName != "" {
out = &buf
}
mode := printer.TabIndent | printer.UseSpaces
err := (&printer.Config{Mode: mode, Tabwidth: p.TabWidth}).Fprint(&tconv{p: p, output: out}, fset, x)
if err != nil {
log.Print(err)
}
// Add comments to struct fields saying which Go version introducd them.
if structName != "" {
fieldSince := apiInfo.fieldSince[structName]
typeSince := apiInfo.typeSince[structName]
// Add/rewrite comments on struct fields to note which Go version added them.
var buf2 bytes.Buffer
buf2.Grow(buf.Len() + len(" // Added in Go 1.n")*10)
bs := bufio.NewScanner(&buf)
for bs.Scan() {
line := bs.Bytes()
field := firstIdent(line)
var since string
if field != "" {
since = fieldSince[field]
if since != "" && since == typeSince {
// Don't highlight field versions if they were the
// same as the struct itself.
since = ""
}
}
if since == "" {
buf2.Write(line)
} else {
if bytes.Contains(line, slashSlash) {
line = bytes.TrimRight(line, " \t.")
buf2.Write(line)
buf2.WriteString("; added in Go ")
} else {
buf2.Write(line)
buf2.WriteString(" // Go ")
}
buf2.WriteString(since)
}
buf2.WriteByte('\n')
}
w.Write(buf2.Bytes())
}
}
var slashSlash = []byte("//")
// WriteNode writes x to w.
// TODO(bgarcia) Is this method needed? It's just a wrapper for p.writeNode.
func (p *Presentation) WriteNode(w io.Writer, fset *token.FileSet, x interface{}) {
p.writeNode(w, nil, fset, x)
}
// firstIdent returns the first identifier in x.
// This actually parses "identifiers" that begin with numbers too, but we
// never feed it such input, so it's fine.
func firstIdent(x []byte) string {
x = bytes.TrimSpace(x)
i := bytes.IndexFunc(x, func(r rune) bool { return !unicode.IsLetter(r) && !unicode.IsNumber(r) })
if i == -1 {
return string(x)
}
return string(x[:i])
}