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-rw-r--r--src/cmd/godoc/index.go1073
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diff --git a/src/cmd/godoc/index.go b/src/cmd/godoc/index.go
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-// Copyright 2009 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// This file contains the infrastructure to create an
-// identifier and full-text index for a set of Go files.
-//
-// Algorithm for identifier index:
-// - traverse all .go files of the file tree specified by root
-// - for each identifier (word) encountered, collect all occurrences (spots)
-// into a list; this produces a list of spots for each word
-// - reduce the lists: from a list of spots to a list of FileRuns,
-// and from a list of FileRuns into a list of PakRuns
-// - make a HitList from the PakRuns
-//
-// Details:
-// - keep two lists per word: one containing package-level declarations
-// that have snippets, and one containing all other spots
-// - keep the snippets in a separate table indexed by snippet index
-// and store the snippet index in place of the line number in a SpotInfo
-// (the line number for spots with snippets is stored in the snippet)
-// - at the end, create lists of alternative spellings for a given
-// word
-//
-// Algorithm for full text index:
-// - concatenate all source code in a byte buffer (in memory)
-// - add the files to a file set in lockstep as they are added to the byte
-// buffer such that a byte buffer offset corresponds to the Pos value for
-// that file location
-// - create a suffix array from the concatenated sources
-//
-// String lookup in full text index:
-// - use the suffix array to lookup a string's offsets - the offsets
-// correspond to the Pos values relative to the file set
-// - translate the Pos values back into file and line information and
-// sort the result
-
-package main
-
-import (
- "bufio"
- "bytes"
- "encoding/gob"
- "errors"
- "go/ast"
- "go/parser"
- "go/token"
- "index/suffixarray"
- "io"
- "os"
- pathpkg "path"
- "regexp"
- "sort"
- "strings"
- "time"
- "unicode"
-)
-
-// ----------------------------------------------------------------------------
-// InterfaceSlice is a helper type for sorting interface
-// slices according to some slice-specific sort criteria.
-
-type Comparer func(x, y interface{}) bool
-
-type InterfaceSlice struct {
- slice []interface{}
- less Comparer
-}
-
-func (p *InterfaceSlice) Len() int { return len(p.slice) }
-func (p *InterfaceSlice) Less(i, j int) bool { return p.less(p.slice[i], p.slice[j]) }
-func (p *InterfaceSlice) Swap(i, j int) { p.slice[i], p.slice[j] = p.slice[j], p.slice[i] }
-
-// ----------------------------------------------------------------------------
-// RunList
-
-// A RunList is a list of entries that can be sorted according to some
-// criteria. A RunList may be compressed by grouping "runs" of entries
-// which are equal (according to the sort critera) into a new RunList of
-// runs. For instance, a RunList containing pairs (x, y) may be compressed
-// into a RunList containing pair runs (x, {y}) where each run consists of
-// a list of y's with the same x.
-type RunList []interface{}
-
-func (h RunList) sort(less Comparer) {
- sort.Sort(&InterfaceSlice{h, less})
-}
-
-// Compress entries which are the same according to a sort criteria
-// (specified by less) into "runs".
-func (h RunList) reduce(less Comparer, newRun func(h RunList) interface{}) RunList {
- if len(h) == 0 {
- return nil
- }
- // len(h) > 0
-
- // create runs of entries with equal values
- h.sort(less)
-
- // for each run, make a new run object and collect them in a new RunList
- var hh RunList
- i, x := 0, h[0]
- for j, y := range h {
- if less(x, y) {
- hh = append(hh, newRun(h[i:j]))
- i, x = j, h[j] // start a new run
- }
- }
- // add final run, if any
- if i < len(h) {
- hh = append(hh, newRun(h[i:]))
- }
-
- return hh
-}
-
-// ----------------------------------------------------------------------------
-// SpotInfo
-
-// A SpotInfo value describes a particular identifier spot in a given file;
-// It encodes three values: the SpotKind (declaration or use), a line or
-// snippet index "lori", and whether it's a line or index.
-//
-// The following encoding is used:
-//
-// bits 32 4 1 0
-// value [lori|kind|isIndex]
-//
-type SpotInfo uint32
-
-// SpotKind describes whether an identifier is declared (and what kind of
-// declaration) or used.
-type SpotKind uint32
-
-const (
- PackageClause SpotKind = iota
- ImportDecl
- ConstDecl
- TypeDecl
- VarDecl
- FuncDecl
- MethodDecl
- Use
- nKinds
-)
-
-func init() {
- // sanity check: if nKinds is too large, the SpotInfo
- // accessor functions may need to be updated
- if nKinds > 8 {
- panic("internal error: nKinds > 8")
- }
-}
-
-// makeSpotInfo makes a SpotInfo.
-func makeSpotInfo(kind SpotKind, lori int, isIndex bool) SpotInfo {
- // encode lori: bits [4..32)
- x := SpotInfo(lori) << 4
- if int(x>>4) != lori {
- // lori value doesn't fit - since snippet indices are
- // most certainly always smaller then 1<<28, this can
- // only happen for line numbers; give it no line number (= 0)
- x = 0
- }
- // encode kind: bits [1..4)
- x |= SpotInfo(kind) << 1
- // encode isIndex: bit 0
- if isIndex {
- x |= 1
- }
- return x
-}
-
-func (x SpotInfo) Kind() SpotKind { return SpotKind(x >> 1 & 7) }
-func (x SpotInfo) Lori() int { return int(x >> 4) }
-func (x SpotInfo) IsIndex() bool { return x&1 != 0 }
-
-// ----------------------------------------------------------------------------
-// KindRun
-
-// Debugging support. Disable to see multiple entries per line.
-const removeDuplicates = true
-
-// A KindRun is a run of SpotInfos of the same kind in a given file.
-// The kind (3 bits) is stored in each SpotInfo element; to find the
-// kind of a KindRun, look at any of it's elements.
-type KindRun []SpotInfo
-
-// KindRuns are sorted by line number or index. Since the isIndex bit
-// is always the same for all infos in one list we can compare lori's.
-func (k KindRun) Len() int { return len(k) }
-func (k KindRun) Less(i, j int) bool { return k[i].Lori() < k[j].Lori() }
-func (k KindRun) Swap(i, j int) { k[i], k[j] = k[j], k[i] }
-
-// FileRun contents are sorted by Kind for the reduction into KindRuns.
-func lessKind(x, y interface{}) bool { return x.(SpotInfo).Kind() < y.(SpotInfo).Kind() }
-
-// newKindRun allocates a new KindRun from the SpotInfo run h.
-func newKindRun(h RunList) interface{} {
- run := make(KindRun, len(h))
- for i, x := range h {
- run[i] = x.(SpotInfo)
- }
-
- // Spots were sorted by file and kind to create this run.
- // Within this run, sort them by line number or index.
- sort.Sort(run)
-
- if removeDuplicates {
- // Since both the lori and kind field must be
- // same for duplicates, and since the isIndex
- // bit is always the same for all infos in one
- // list we can simply compare the entire info.
- k := 0
- prev := SpotInfo(1<<32 - 1) // an unlikely value
- for _, x := range run {
- if x != prev {
- run[k] = x
- k++
- prev = x
- }
- }
- run = run[0:k]
- }
-
- return run
-}
-
-// ----------------------------------------------------------------------------
-// FileRun
-
-// A Pak describes a Go package.
-type Pak struct {
- Path string // path of directory containing the package
- Name string // package name as declared by package clause
-}
-
-// Paks are sorted by name (primary key) and by import path (secondary key).
-func (p *Pak) less(q *Pak) bool {
- return p.Name < q.Name || p.Name == q.Name && p.Path < q.Path
-}
-
-// A File describes a Go file.
-type File struct {
- Name string // directory-local file name
- Pak *Pak // the package to which the file belongs
-}
-
-// Path returns the file path of f.
-func (f *File) Path() string {
- return pathpkg.Join(f.Pak.Path, f.Name)
-}
-
-// A Spot describes a single occurrence of a word.
-type Spot struct {
- File *File
- Info SpotInfo
-}
-
-// A FileRun is a list of KindRuns belonging to the same file.
-type FileRun struct {
- File *File
- Groups []KindRun
-}
-
-// Spots are sorted by file path for the reduction into FileRuns.
-func lessSpot(x, y interface{}) bool {
- fx := x.(Spot).File
- fy := y.(Spot).File
- // same as "return fx.Path() < fy.Path()" but w/o computing the file path first
- px := fx.Pak.Path
- py := fy.Pak.Path
- return px < py || px == py && fx.Name < fy.Name
-}
-
-// newFileRun allocates a new FileRun from the Spot run h.
-func newFileRun(h RunList) interface{} {
- file := h[0].(Spot).File
-
- // reduce the list of Spots into a list of KindRuns
- h1 := make(RunList, len(h))
- for i, x := range h {
- h1[i] = x.(Spot).Info
- }
- h2 := h1.reduce(lessKind, newKindRun)
-
- // create the FileRun
- groups := make([]KindRun, len(h2))
- for i, x := range h2 {
- groups[i] = x.(KindRun)
- }
- return &FileRun{file, groups}
-}
-
-// ----------------------------------------------------------------------------
-// PakRun
-
-// A PakRun describes a run of *FileRuns of a package.
-type PakRun struct {
- Pak *Pak
- Files []*FileRun
-}
-
-// Sorting support for files within a PakRun.
-func (p *PakRun) Len() int { return len(p.Files) }
-func (p *PakRun) Less(i, j int) bool { return p.Files[i].File.Name < p.Files[j].File.Name }
-func (p *PakRun) Swap(i, j int) { p.Files[i], p.Files[j] = p.Files[j], p.Files[i] }
-
-// FileRuns are sorted by package for the reduction into PakRuns.
-func lessFileRun(x, y interface{}) bool {
- return x.(*FileRun).File.Pak.less(y.(*FileRun).File.Pak)
-}
-
-// newPakRun allocates a new PakRun from the *FileRun run h.
-func newPakRun(h RunList) interface{} {
- pak := h[0].(*FileRun).File.Pak
- files := make([]*FileRun, len(h))
- for i, x := range h {
- files[i] = x.(*FileRun)
- }
- run := &PakRun{pak, files}
- sort.Sort(run) // files were sorted by package; sort them by file now
- return run
-}
-
-// ----------------------------------------------------------------------------
-// HitList
-
-// A HitList describes a list of PakRuns.
-type HitList []*PakRun
-
-// PakRuns are sorted by package.
-func lessPakRun(x, y interface{}) bool { return x.(*PakRun).Pak.less(y.(*PakRun).Pak) }
-
-func reduce(h0 RunList) HitList {
- // reduce a list of Spots into a list of FileRuns
- h1 := h0.reduce(lessSpot, newFileRun)
- // reduce a list of FileRuns into a list of PakRuns
- h2 := h1.reduce(lessFileRun, newPakRun)
- // sort the list of PakRuns by package
- h2.sort(lessPakRun)
- // create a HitList
- h := make(HitList, len(h2))
- for i, p := range h2 {
- h[i] = p.(*PakRun)
- }
- return h
-}
-
-// filter returns a new HitList created by filtering
-// all PakRuns from h that have a matching pakname.
-func (h HitList) filter(pakname string) HitList {
- var hh HitList
- for _, p := range h {
- if p.Pak.Name == pakname {
- hh = append(hh, p)
- }
- }
- return hh
-}
-
-// ----------------------------------------------------------------------------
-// AltWords
-
-type wordPair struct {
- canon string // canonical word spelling (all lowercase)
- alt string // alternative spelling
-}
-
-// An AltWords describes a list of alternative spellings for a
-// canonical (all lowercase) spelling of a word.
-type AltWords struct {
- Canon string // canonical word spelling (all lowercase)
- Alts []string // alternative spelling for the same word
-}
-
-// wordPairs are sorted by their canonical spelling.
-func lessWordPair(x, y interface{}) bool { return x.(*wordPair).canon < y.(*wordPair).canon }
-
-// newAltWords allocates a new AltWords from the *wordPair run h.
-func newAltWords(h RunList) interface{} {
- canon := h[0].(*wordPair).canon
- alts := make([]string, len(h))
- for i, x := range h {
- alts[i] = x.(*wordPair).alt
- }
- return &AltWords{canon, alts}
-}
-
-func (a *AltWords) filter(s string) *AltWords {
- var alts []string
- for _, w := range a.Alts {
- if w != s {
- alts = append(alts, w)
- }
- }
- if len(alts) > 0 {
- return &AltWords{a.Canon, alts}
- }
- return nil
-}
-
-// ----------------------------------------------------------------------------
-// Indexer
-
-// Adjust these flags as seems best.
-const includeMainPackages = true
-const includeTestFiles = true
-
-type IndexResult struct {
- Decls RunList // package-level declarations (with snippets)
- Others RunList // all other occurrences
-}
-
-// Statistics provides statistics information for an index.
-type Statistics struct {
- Bytes int // total size of indexed source files
- Files int // number of indexed source files
- Lines int // number of lines (all files)
- Words int // number of different identifiers
- Spots int // number of identifier occurrences
-}
-
-// An Indexer maintains the data structures and provides the machinery
-// for indexing .go files under a file tree. It implements the path.Visitor
-// interface for walking file trees, and the ast.Visitor interface for
-// walking Go ASTs.
-type Indexer struct {
- fset *token.FileSet // file set for all indexed files
- sources bytes.Buffer // concatenated sources
- packages map[string]*Pak // map of canonicalized *Paks
- words map[string]*IndexResult // RunLists of Spots
- snippets []*Snippet // indices are stored in SpotInfos
- current *token.File // last file added to file set
- file *File // AST for current file
- decl ast.Decl // AST for current decl
- stats Statistics
-}
-
-func (x *Indexer) lookupPackage(path, name string) *Pak {
- // In the source directory tree, more than one package may
- // live in the same directory. For the packages map, construct
- // a key that includes both the directory path and the package
- // name.
- key := path + ":" + name
- pak := x.packages[key]
- if pak == nil {
- pak = &Pak{path, name}
- x.packages[key] = pak
- }
- return pak
-}
-
-func (x *Indexer) addSnippet(s *Snippet) int {
- index := len(x.snippets)
- x.snippets = append(x.snippets, s)
- return index
-}
-
-func (x *Indexer) visitIdent(kind SpotKind, id *ast.Ident) {
- if id != nil {
- lists, found := x.words[id.Name]
- if !found {
- lists = new(IndexResult)
- x.words[id.Name] = lists
- }
-
- if kind == Use || x.decl == nil {
- // not a declaration or no snippet required
- info := makeSpotInfo(kind, x.current.Line(id.Pos()), false)
- lists.Others = append(lists.Others, Spot{x.file, info})
- } else {
- // a declaration with snippet
- index := x.addSnippet(NewSnippet(x.fset, x.decl, id))
- info := makeSpotInfo(kind, index, true)
- lists.Decls = append(lists.Decls, Spot{x.file, info})
- }
-
- x.stats.Spots++
- }
-}
-
-func (x *Indexer) visitFieldList(kind SpotKind, list *ast.FieldList) {
- for _, f := range list.List {
- x.decl = nil // no snippets for fields
- for _, name := range f.Names {
- x.visitIdent(kind, name)
- }
- ast.Walk(x, f.Type)
- // ignore tag - not indexed at the moment
- }
-}
-
-func (x *Indexer) visitSpec(kind SpotKind, spec ast.Spec) {
- switch n := spec.(type) {
- case *ast.ImportSpec:
- x.visitIdent(ImportDecl, n.Name)
- // ignore path - not indexed at the moment
-
- case *ast.ValueSpec:
- for _, n := range n.Names {
- x.visitIdent(kind, n)
- }
- ast.Walk(x, n.Type)
- for _, v := range n.Values {
- ast.Walk(x, v)
- }
-
- case *ast.TypeSpec:
- x.visitIdent(TypeDecl, n.Name)
- ast.Walk(x, n.Type)
- }
-}
-
-func (x *Indexer) visitGenDecl(decl *ast.GenDecl) {
- kind := VarDecl
- if decl.Tok == token.CONST {
- kind = ConstDecl
- }
- x.decl = decl
- for _, s := range decl.Specs {
- x.visitSpec(kind, s)
- }
-}
-
-func (x *Indexer) Visit(node ast.Node) ast.Visitor {
- switch n := node.(type) {
- case nil:
- // nothing to do
-
- case *ast.Ident:
- x.visitIdent(Use, n)
-
- case *ast.FieldList:
- x.visitFieldList(VarDecl, n)
-
- case *ast.InterfaceType:
- x.visitFieldList(MethodDecl, n.Methods)
-
- case *ast.DeclStmt:
- // local declarations should only be *ast.GenDecls;
- // ignore incorrect ASTs
- if decl, ok := n.Decl.(*ast.GenDecl); ok {
- x.decl = nil // no snippets for local declarations
- x.visitGenDecl(decl)
- }
-
- case *ast.GenDecl:
- x.decl = n
- x.visitGenDecl(n)
-
- case *ast.FuncDecl:
- kind := FuncDecl
- if n.Recv != nil {
- kind = MethodDecl
- ast.Walk(x, n.Recv)
- }
- x.decl = n
- x.visitIdent(kind, n.Name)
- ast.Walk(x, n.Type)
- if n.Body != nil {
- ast.Walk(x, n.Body)
- }
-
- case *ast.File:
- x.decl = nil
- x.visitIdent(PackageClause, n.Name)
- for _, d := range n.Decls {
- ast.Walk(x, d)
- }
-
- default:
- return x
- }
-
- return nil
-}
-
-func pkgName(filename string) string {
- // use a new file set each time in order to not pollute the indexer's
- // file set (which must stay in sync with the concatenated source code)
- file, err := parser.ParseFile(token.NewFileSet(), filename, nil, parser.PackageClauseOnly)
- if err != nil || file == nil {
- return ""
- }
- return file.Name.Name
-}
-
-// addFile adds a file to the index if possible and returns the file set file
-// and the file's AST if it was successfully parsed as a Go file. If addFile
-// failed (that is, if the file was not added), it returns file == nil.
-func (x *Indexer) addFile(filename string, goFile bool) (file *token.File, ast *ast.File) {
- // open file
- f, err := fs.Open(filename)
- if err != nil {
- return
- }
- defer f.Close()
-
- // The file set's base offset and x.sources size must be in lock-step;
- // this permits the direct mapping of suffix array lookup results to
- // to corresponding Pos values.
- //
- // When a file is added to the file set, its offset base increases by
- // the size of the file + 1; and the initial base offset is 1. Add an
- // extra byte to the sources here.
- x.sources.WriteByte(0)
-
- // If the sources length doesn't match the file set base at this point
- // the file set implementation changed or we have another error.
- base := x.fset.Base()
- if x.sources.Len() != base {
- panic("internal error: file base incorrect")
- }
-
- // append file contents (src) to x.sources
- if _, err := x.sources.ReadFrom(f); err == nil {
- src := x.sources.Bytes()[base:]
-
- if goFile {
- // parse the file and in the process add it to the file set
- if ast, err = parser.ParseFile(x.fset, filename, src, parser.ParseComments); err == nil {
- file = x.fset.File(ast.Pos()) // ast.Pos() is inside the file
- return
- }
- // file has parse errors, and the AST may be incorrect -
- // set lines information explicitly and index as ordinary
- // text file (cannot fall through to the text case below
- // because the file has already been added to the file set
- // by the parser)
- file = x.fset.File(token.Pos(base)) // token.Pos(base) is inside the file
- file.SetLinesForContent(src)
- ast = nil
- return
- }
-
- if isText(src) {
- // only add the file to the file set (for the full text index)
- file = x.fset.AddFile(filename, x.fset.Base(), len(src))
- file.SetLinesForContent(src)
- return
- }
- }
-
- // discard possibly added data
- x.sources.Truncate(base - 1) // -1 to remove added byte 0 since no file was added
- return
-}
-
-// Design note: Using an explicit white list of permitted files for indexing
-// makes sure that the important files are included and massively reduces the
-// number of files to index. The advantage over a blacklist is that unexpected
-// (non-blacklisted) files won't suddenly explode the index.
-
-// Files are whitelisted if they have a file name or extension
-// present as key in whitelisted.
-var whitelisted = map[string]bool{
- ".bash": true,
- ".c": true,
- ".css": true,
- ".go": true,
- ".goc": true,
- ".h": true,
- ".html": true,
- ".js": true,
- ".out": true,
- ".py": true,
- ".s": true,
- ".sh": true,
- ".txt": true,
- ".xml": true,
- "AUTHORS": true,
- "CONTRIBUTORS": true,
- "LICENSE": true,
- "Makefile": true,
- "PATENTS": true,
- "README": true,
-}
-
-// isWhitelisted returns true if a file is on the list
-// of "permitted" files for indexing. The filename must
-// be the directory-local name of the file.
-func isWhitelisted(filename string) bool {
- key := pathpkg.Ext(filename)
- if key == "" {
- // file has no extension - use entire filename
- key = filename
- }
- return whitelisted[key]
-}
-
-func (x *Indexer) visitFile(dirname string, f os.FileInfo, fulltextIndex bool) {
- if f.IsDir() {
- return
- }
-
- filename := pathpkg.Join(dirname, f.Name())
- goFile := false
-
- switch {
- case isGoFile(f):
- if !includeTestFiles && (!isPkgFile(f) || strings.HasPrefix(filename, "test/")) {
- return
- }
- if !includeMainPackages && pkgName(filename) == "main" {
- return
- }
- goFile = true
-
- case !fulltextIndex || !isWhitelisted(f.Name()):
- return
- }
-
- file, fast := x.addFile(filename, goFile)
- if file == nil {
- return // addFile failed
- }
-
- if fast != nil {
- // we've got a Go file to index
- x.current = file
- pak := x.lookupPackage(dirname, fast.Name.Name)
- x.file = &File{f.Name(), pak}
- ast.Walk(x, fast)
- }
-
- // update statistics
- x.stats.Bytes += file.Size()
- x.stats.Files++
- x.stats.Lines += file.LineCount()
-}
-
-// ----------------------------------------------------------------------------
-// Index
-
-type LookupResult struct {
- Decls HitList // package-level declarations (with snippets)
- Others HitList // all other occurrences
-}
-
-type Index struct {
- fset *token.FileSet // file set used during indexing; nil if no textindex
- suffixes *suffixarray.Index // suffixes for concatenated sources; nil if no textindex
- words map[string]*LookupResult // maps words to hit lists
- alts map[string]*AltWords // maps canonical(words) to lists of alternative spellings
- snippets []*Snippet // all snippets, indexed by snippet index
- stats Statistics
-}
-
-func canonical(w string) string { return strings.ToLower(w) }
-
-// NewIndex creates a new index for the .go files
-// in the directories given by dirnames.
-//
-func NewIndex(dirnames <-chan string, fulltextIndex bool, throttle float64) *Index {
- var x Indexer
- th := NewThrottle(throttle, 100*time.Millisecond) // run at least 0.1s at a time
-
- // initialize Indexer
- // (use some reasonably sized maps to start)
- x.fset = token.NewFileSet()
- x.packages = make(map[string]*Pak, 256)
- x.words = make(map[string]*IndexResult, 8192)
-
- // index all files in the directories given by dirnames
- for dirname := range dirnames {
- list, err := fs.ReadDir(dirname)
- if err != nil {
- continue // ignore this directory
- }
- for _, f := range list {
- if !f.IsDir() {
- x.visitFile(dirname, f, fulltextIndex)
- }
- th.Throttle()
- }
- }
-
- if !fulltextIndex {
- // the file set, the current file, and the sources are
- // not needed after indexing if no text index is built -
- // help GC and clear them
- x.fset = nil
- x.sources.Reset()
- x.current = nil // contains reference to fset!
- }
-
- // for each word, reduce the RunLists into a LookupResult;
- // also collect the word with its canonical spelling in a
- // word list for later computation of alternative spellings
- words := make(map[string]*LookupResult)
- var wlist RunList
- for w, h := range x.words {
- decls := reduce(h.Decls)
- others := reduce(h.Others)
- words[w] = &LookupResult{
- Decls: decls,
- Others: others,
- }
- wlist = append(wlist, &wordPair{canonical(w), w})
- th.Throttle()
- }
- x.stats.Words = len(words)
-
- // reduce the word list {canonical(w), w} into
- // a list of AltWords runs {canonical(w), {w}}
- alist := wlist.reduce(lessWordPair, newAltWords)
-
- // convert alist into a map of alternative spellings
- alts := make(map[string]*AltWords)
- for i := 0; i < len(alist); i++ {
- a := alist[i].(*AltWords)
- alts[a.Canon] = a
- }
-
- // create text index
- var suffixes *suffixarray.Index
- if fulltextIndex {
- suffixes = suffixarray.New(x.sources.Bytes())
- }
-
- return &Index{x.fset, suffixes, words, alts, x.snippets, x.stats}
-}
-
-type fileIndex struct {
- Words map[string]*LookupResult
- Alts map[string]*AltWords
- Snippets []*Snippet
- Fulltext bool
-}
-
-func (x *fileIndex) Write(w io.Writer) error {
- return gob.NewEncoder(w).Encode(x)
-}
-
-func (x *fileIndex) Read(r io.Reader) error {
- return gob.NewDecoder(r).Decode(x)
-}
-
-// Write writes the index x to w.
-func (x *Index) Write(w io.Writer) error {
- fulltext := false
- if x.suffixes != nil {
- fulltext = true
- }
- fx := fileIndex{
- x.words,
- x.alts,
- x.snippets,
- fulltext,
- }
- if err := fx.Write(w); err != nil {
- return err
- }
- if fulltext {
- encode := func(x interface{}) error {
- return gob.NewEncoder(w).Encode(x)
- }
- if err := x.fset.Write(encode); err != nil {
- return err
- }
- if err := x.suffixes.Write(w); err != nil {
- return err
- }
- }
- return nil
-}
-
-// Read reads the index from r into x; x must not be nil.
-// If r does not also implement io.ByteReader, it will be wrapped in a bufio.Reader.
-func (x *Index) Read(r io.Reader) error {
- // We use the ability to read bytes as a plausible surrogate for buffering.
- if _, ok := r.(io.ByteReader); !ok {
- r = bufio.NewReader(r)
- }
- var fx fileIndex
- if err := fx.Read(r); err != nil {
- return err
- }
- x.words = fx.Words
- x.alts = fx.Alts
- x.snippets = fx.Snippets
- if fx.Fulltext {
- x.fset = token.NewFileSet()
- decode := func(x interface{}) error {
- return gob.NewDecoder(r).Decode(x)
- }
- if err := x.fset.Read(decode); err != nil {
- return err
- }
- x.suffixes = new(suffixarray.Index)
- if err := x.suffixes.Read(r); err != nil {
- return err
- }
- }
- return nil
-}
-
-// Stats() returns index statistics.
-func (x *Index) Stats() Statistics {
- return x.stats
-}
-
-func (x *Index) lookupWord(w string) (match *LookupResult, alt *AltWords) {
- match = x.words[w]
- alt = x.alts[canonical(w)]
- // remove current spelling from alternatives
- // (if there is no match, the alternatives do
- // not contain the current spelling)
- if match != nil && alt != nil {
- alt = alt.filter(w)
- }
- return
-}
-
-// isIdentifier reports whether s is a Go identifier.
-func isIdentifier(s string) bool {
- for i, ch := range s {
- if unicode.IsLetter(ch) || ch == ' ' || i > 0 && unicode.IsDigit(ch) {
- continue
- }
- return false
- }
- return len(s) > 0
-}
-
-// For a given query, which is either a single identifier or a qualified
-// identifier, Lookup returns a list of packages, a LookupResult, and a
-// list of alternative spellings, if any. Any and all results may be nil.
-// If the query syntax is wrong, an error is reported.
-func (x *Index) Lookup(query string) (paks HitList, match *LookupResult, alt *AltWords, err error) {
- ss := strings.Split(query, ".")
-
- // check query syntax
- for _, s := range ss {
- if !isIdentifier(s) {
- err = errors.New("all query parts must be identifiers")
- return
- }
- }
-
- // handle simple and qualified identifiers
- switch len(ss) {
- case 1:
- ident := ss[0]
- match, alt = x.lookupWord(ident)
- if match != nil {
- // found a match - filter packages with same name
- // for the list of packages called ident, if any
- paks = match.Others.filter(ident)
- }
-
- case 2:
- pakname, ident := ss[0], ss[1]
- match, alt = x.lookupWord(ident)
- if match != nil {
- // found a match - filter by package name
- // (no paks - package names are not qualified)
- decls := match.Decls.filter(pakname)
- others := match.Others.filter(pakname)
- match = &LookupResult{decls, others}
- }
-
- default:
- err = errors.New("query is not a (qualified) identifier")
- }
-
- return
-}
-
-func (x *Index) Snippet(i int) *Snippet {
- // handle illegal snippet indices gracefully
- if 0 <= i && i < len(x.snippets) {
- return x.snippets[i]
- }
- return nil
-}
-
-type positionList []struct {
- filename string
- line int
-}
-
-func (list positionList) Len() int { return len(list) }
-func (list positionList) Less(i, j int) bool { return list[i].filename < list[j].filename }
-func (list positionList) Swap(i, j int) { list[i], list[j] = list[j], list[i] }
-
-// unique returns the list sorted and with duplicate entries removed
-func unique(list []int) []int {
- sort.Ints(list)
- var last int
- i := 0
- for _, x := range list {
- if i == 0 || x != last {
- last = x
- list[i] = x
- i++
- }
- }
- return list[0:i]
-}
-
-// A FileLines value specifies a file and line numbers within that file.
-type FileLines struct {
- Filename string
- Lines []int
-}
-
-// LookupRegexp returns the number of matches and the matches where a regular
-// expression r is found in the full text index. At most n matches are
-// returned (thus found <= n).
-//
-func (x *Index) LookupRegexp(r *regexp.Regexp, n int) (found int, result []FileLines) {
- if x.suffixes == nil || n <= 0 {
- return
- }
- // n > 0
-
- var list positionList
- // FindAllIndex may returns matches that span across file boundaries.
- // Such matches are unlikely, buf after eliminating them we may end up
- // with fewer than n matches. If we don't have enough at the end, redo
- // the search with an increased value n1, but only if FindAllIndex
- // returned all the requested matches in the first place (if it
- // returned fewer than that there cannot be more).
- for n1 := n; found < n; n1 += n - found {
- found = 0
- matches := x.suffixes.FindAllIndex(r, n1)
- // compute files, exclude matches that span file boundaries,
- // and map offsets to file-local offsets
- list = make(positionList, len(matches))
- for _, m := range matches {
- // by construction, an offset corresponds to the Pos value
- // for the file set - use it to get the file and line
- p := token.Pos(m[0])
- if file := x.fset.File(p); file != nil {
- if base := file.Base(); base <= m[1] && m[1] <= base+file.Size() {
- // match [m[0], m[1]) is within the file boundaries
- list[found].filename = file.Name()
- list[found].line = file.Line(p)
- found++
- }
- }
- }
- if found == n || len(matches) < n1 {
- // found all matches or there's no chance to find more
- break
- }
- }
- list = list[0:found]
- sort.Sort(list) // sort by filename
-
- // collect matches belonging to the same file
- var last string
- var lines []int
- addLines := func() {
- if len(lines) > 0 {
- // remove duplicate lines
- result = append(result, FileLines{last, unique(lines)})
- lines = nil
- }
- }
- for _, m := range list {
- if m.filename != last {
- addLines()
- last = m.filename
- }
- lines = append(lines, m.line)
- }
- addLines()
-
- return
-}
generated by cgit v1.2.3 (git 2.46.0) at 2025-11-02 08:23:29 +0000