mirror of
https://codeberg.org/forgejo/forgejo
synced 2024-12-05 02:54:46 +01:00
436 lines
12 KiB
Go
436 lines
12 KiB
Go
|
// Copyright 2010 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.
|
||
|
|
||
|
// TODO(gri) consider making this a separate package outside the go directory.
|
||
|
|
||
|
package token
|
||
|
|
||
|
import (
|
||
|
"fmt"
|
||
|
"sort"
|
||
|
"sync"
|
||
|
)
|
||
|
|
||
|
// -----------------------------------------------------------------------------
|
||
|
// Positions
|
||
|
|
||
|
// Position describes an arbitrary source position
|
||
|
// including the file, line, and column location.
|
||
|
// A Position is valid if the line number is > 0.
|
||
|
//
|
||
|
type Position struct {
|
||
|
Filename string // filename, if any
|
||
|
Offset int // offset, starting at 0
|
||
|
Line int // line number, starting at 1
|
||
|
Column int // column number, starting at 1 (character count)
|
||
|
}
|
||
|
|
||
|
// IsValid returns true if the position is valid.
|
||
|
func (pos *Position) IsValid() bool { return pos.Line > 0 }
|
||
|
|
||
|
// String returns a string in one of several forms:
|
||
|
//
|
||
|
// file:line:column valid position with file name
|
||
|
// line:column valid position without file name
|
||
|
// file invalid position with file name
|
||
|
// - invalid position without file name
|
||
|
//
|
||
|
func (pos Position) String() string {
|
||
|
s := pos.Filename
|
||
|
if pos.IsValid() {
|
||
|
if s != "" {
|
||
|
s += ":"
|
||
|
}
|
||
|
s += fmt.Sprintf("%d:%d", pos.Line, pos.Column)
|
||
|
}
|
||
|
if s == "" {
|
||
|
s = "-"
|
||
|
}
|
||
|
return s
|
||
|
}
|
||
|
|
||
|
// Pos is a compact encoding of a source position within a file set.
|
||
|
// It can be converted into a Position for a more convenient, but much
|
||
|
// larger, representation.
|
||
|
//
|
||
|
// The Pos value for a given file is a number in the range [base, base+size],
|
||
|
// where base and size are specified when adding the file to the file set via
|
||
|
// AddFile.
|
||
|
//
|
||
|
// To create the Pos value for a specific source offset, first add
|
||
|
// the respective file to the current file set (via FileSet.AddFile)
|
||
|
// and then call File.Pos(offset) for that file. Given a Pos value p
|
||
|
// for a specific file set fset, the corresponding Position value is
|
||
|
// obtained by calling fset.Position(p).
|
||
|
//
|
||
|
// Pos values can be compared directly with the usual comparison operators:
|
||
|
// If two Pos values p and q are in the same file, comparing p and q is
|
||
|
// equivalent to comparing the respective source file offsets. If p and q
|
||
|
// are in different files, p < q is true if the file implied by p was added
|
||
|
// to the respective file set before the file implied by q.
|
||
|
//
|
||
|
type Pos int
|
||
|
|
||
|
// The zero value for Pos is NoPos; there is no file and line information
|
||
|
// associated with it, and NoPos().IsValid() is false. NoPos is always
|
||
|
// smaller than any other Pos value. The corresponding Position value
|
||
|
// for NoPos is the zero value for Position.
|
||
|
//
|
||
|
const NoPos Pos = 0
|
||
|
|
||
|
// IsValid returns true if the position is valid.
|
||
|
func (p Pos) IsValid() bool {
|
||
|
return p != NoPos
|
||
|
}
|
||
|
|
||
|
// -----------------------------------------------------------------------------
|
||
|
// File
|
||
|
|
||
|
// A File is a handle for a file belonging to a FileSet.
|
||
|
// A File has a name, size, and line offset table.
|
||
|
//
|
||
|
type File struct {
|
||
|
set *FileSet
|
||
|
name string // file name as provided to AddFile
|
||
|
base int // Pos value range for this file is [base...base+size]
|
||
|
size int // file size as provided to AddFile
|
||
|
|
||
|
// lines and infos are protected by set.mutex
|
||
|
lines []int
|
||
|
infos []lineInfo
|
||
|
}
|
||
|
|
||
|
// Name returns the file name of file f as registered with AddFile.
|
||
|
func (f *File) Name() string {
|
||
|
return f.name
|
||
|
}
|
||
|
|
||
|
// Base returns the base offset of file f as registered with AddFile.
|
||
|
func (f *File) Base() int {
|
||
|
return f.base
|
||
|
}
|
||
|
|
||
|
// Size returns the size of file f as registered with AddFile.
|
||
|
func (f *File) Size() int {
|
||
|
return f.size
|
||
|
}
|
||
|
|
||
|
// LineCount returns the number of lines in file f.
|
||
|
func (f *File) LineCount() int {
|
||
|
f.set.mutex.RLock()
|
||
|
n := len(f.lines)
|
||
|
f.set.mutex.RUnlock()
|
||
|
return n
|
||
|
}
|
||
|
|
||
|
// AddLine adds the line offset for a new line.
|
||
|
// The line offset must be larger than the offset for the previous line
|
||
|
// and smaller than the file size; otherwise the line offset is ignored.
|
||
|
//
|
||
|
func (f *File) AddLine(offset int) {
|
||
|
f.set.mutex.Lock()
|
||
|
if i := len(f.lines); (i == 0 || f.lines[i-1] < offset) && offset < f.size {
|
||
|
f.lines = append(f.lines, offset)
|
||
|
}
|
||
|
f.set.mutex.Unlock()
|
||
|
}
|
||
|
|
||
|
// SetLines sets the line offsets for a file and returns true if successful.
|
||
|
// The line offsets are the offsets of the first character of each line;
|
||
|
// for instance for the content "ab\nc\n" the line offsets are {0, 3}.
|
||
|
// An empty file has an empty line offset table.
|
||
|
// Each line offset must be larger than the offset for the previous line
|
||
|
// and smaller than the file size; otherwise SetLines fails and returns
|
||
|
// false.
|
||
|
//
|
||
|
func (f *File) SetLines(lines []int) bool {
|
||
|
// verify validity of lines table
|
||
|
size := f.size
|
||
|
for i, offset := range lines {
|
||
|
if i > 0 && offset <= lines[i-1] || size <= offset {
|
||
|
return false
|
||
|
}
|
||
|
}
|
||
|
|
||
|
// set lines table
|
||
|
f.set.mutex.Lock()
|
||
|
f.lines = lines
|
||
|
f.set.mutex.Unlock()
|
||
|
return true
|
||
|
}
|
||
|
|
||
|
// SetLinesForContent sets the line offsets for the given file content.
|
||
|
func (f *File) SetLinesForContent(content []byte) {
|
||
|
var lines []int
|
||
|
line := 0
|
||
|
for offset, b := range content {
|
||
|
if line >= 0 {
|
||
|
lines = append(lines, line)
|
||
|
}
|
||
|
line = -1
|
||
|
if b == '\n' {
|
||
|
line = offset + 1
|
||
|
}
|
||
|
}
|
||
|
|
||
|
// set lines table
|
||
|
f.set.mutex.Lock()
|
||
|
f.lines = lines
|
||
|
f.set.mutex.Unlock()
|
||
|
}
|
||
|
|
||
|
// A lineInfo object describes alternative file and line number
|
||
|
// information (such as provided via a //line comment in a .go
|
||
|
// file) for a given file offset.
|
||
|
type lineInfo struct {
|
||
|
// fields are exported to make them accessible to gob
|
||
|
Offset int
|
||
|
Filename string
|
||
|
Line int
|
||
|
}
|
||
|
|
||
|
// AddLineInfo adds alternative file and line number information for
|
||
|
// a given file offset. The offset must be larger than the offset for
|
||
|
// the previously added alternative line info and smaller than the
|
||
|
// file size; otherwise the information is ignored.
|
||
|
//
|
||
|
// AddLineInfo is typically used to register alternative position
|
||
|
// information for //line filename:line comments in source files.
|
||
|
//
|
||
|
func (f *File) AddLineInfo(offset int, filename string, line int) {
|
||
|
f.set.mutex.Lock()
|
||
|
if i := len(f.infos); i == 0 || f.infos[i-1].Offset < offset && offset < f.size {
|
||
|
f.infos = append(f.infos, lineInfo{offset, filename, line})
|
||
|
}
|
||
|
f.set.mutex.Unlock()
|
||
|
}
|
||
|
|
||
|
// Pos returns the Pos value for the given file offset;
|
||
|
// the offset must be <= f.Size().
|
||
|
// f.Pos(f.Offset(p)) == p.
|
||
|
//
|
||
|
func (f *File) Pos(offset int) Pos {
|
||
|
if offset > f.size {
|
||
|
panic("illegal file offset")
|
||
|
}
|
||
|
return Pos(f.base + offset)
|
||
|
}
|
||
|
|
||
|
// Offset returns the offset for the given file position p;
|
||
|
// p must be a valid Pos value in that file.
|
||
|
// f.Offset(f.Pos(offset)) == offset.
|
||
|
//
|
||
|
func (f *File) Offset(p Pos) int {
|
||
|
if int(p) < f.base || int(p) > f.base+f.size {
|
||
|
panic("illegal Pos value")
|
||
|
}
|
||
|
return int(p) - f.base
|
||
|
}
|
||
|
|
||
|
// Line returns the line number for the given file position p;
|
||
|
// p must be a Pos value in that file or NoPos.
|
||
|
//
|
||
|
func (f *File) Line(p Pos) int {
|
||
|
// TODO(gri) this can be implemented much more efficiently
|
||
|
return f.Position(p).Line
|
||
|
}
|
||
|
|
||
|
func searchLineInfos(a []lineInfo, x int) int {
|
||
|
return sort.Search(len(a), func(i int) bool { return a[i].Offset > x }) - 1
|
||
|
}
|
||
|
|
||
|
// info returns the file name, line, and column number for a file offset.
|
||
|
func (f *File) info(offset int) (filename string, line, column int) {
|
||
|
filename = f.name
|
||
|
if i := searchInts(f.lines, offset); i >= 0 {
|
||
|
line, column = i+1, offset-f.lines[i]+1
|
||
|
}
|
||
|
if len(f.infos) > 0 {
|
||
|
// almost no files have extra line infos
|
||
|
if i := searchLineInfos(f.infos, offset); i >= 0 {
|
||
|
alt := &f.infos[i]
|
||
|
filename = alt.Filename
|
||
|
if i := searchInts(f.lines, alt.Offset); i >= 0 {
|
||
|
line += alt.Line - i - 1
|
||
|
}
|
||
|
}
|
||
|
}
|
||
|
return
|
||
|
}
|
||
|
|
||
|
func (f *File) position(p Pos) (pos Position) {
|
||
|
offset := int(p) - f.base
|
||
|
pos.Offset = offset
|
||
|
pos.Filename, pos.Line, pos.Column = f.info(offset)
|
||
|
return
|
||
|
}
|
||
|
|
||
|
// Position returns the Position value for the given file position p;
|
||
|
// p must be a Pos value in that file or NoPos.
|
||
|
//
|
||
|
func (f *File) Position(p Pos) (pos Position) {
|
||
|
if p != NoPos {
|
||
|
if int(p) < f.base || int(p) > f.base+f.size {
|
||
|
panic("illegal Pos value")
|
||
|
}
|
||
|
pos = f.position(p)
|
||
|
}
|
||
|
return
|
||
|
}
|
||
|
|
||
|
// -----------------------------------------------------------------------------
|
||
|
// FileSet
|
||
|
|
||
|
// A FileSet represents a set of source files.
|
||
|
// Methods of file sets are synchronized; multiple goroutines
|
||
|
// may invoke them concurrently.
|
||
|
//
|
||
|
type FileSet struct {
|
||
|
mutex sync.RWMutex // protects the file set
|
||
|
base int // base offset for the next file
|
||
|
files []*File // list of files in the order added to the set
|
||
|
last *File // cache of last file looked up
|
||
|
}
|
||
|
|
||
|
// NewFileSet creates a new file set.
|
||
|
func NewFileSet() *FileSet {
|
||
|
s := new(FileSet)
|
||
|
s.base = 1 // 0 == NoPos
|
||
|
return s
|
||
|
}
|
||
|
|
||
|
// Base returns the minimum base offset that must be provided to
|
||
|
// AddFile when adding the next file.
|
||
|
//
|
||
|
func (s *FileSet) Base() int {
|
||
|
s.mutex.RLock()
|
||
|
b := s.base
|
||
|
s.mutex.RUnlock()
|
||
|
return b
|
||
|
|
||
|
}
|
||
|
|
||
|
// AddFile adds a new file with a given filename, base offset, and file size
|
||
|
// to the file set s and returns the file. Multiple files may have the same
|
||
|
// name. The base offset must not be smaller than the FileSet's Base(), and
|
||
|
// size must not be negative.
|
||
|
//
|
||
|
// Adding the file will set the file set's Base() value to base + size + 1
|
||
|
// as the minimum base value for the next file. The following relationship
|
||
|
// exists between a Pos value p for a given file offset offs:
|
||
|
//
|
||
|
// int(p) = base + offs
|
||
|
//
|
||
|
// with offs in the range [0, size] and thus p in the range [base, base+size].
|
||
|
// For convenience, File.Pos may be used to create file-specific position
|
||
|
// values from a file offset.
|
||
|
//
|
||
|
func (s *FileSet) AddFile(filename string, base, size int) *File {
|
||
|
s.mutex.Lock()
|
||
|
defer s.mutex.Unlock()
|
||
|
if base < s.base || size < 0 {
|
||
|
panic("illegal base or size")
|
||
|
}
|
||
|
// base >= s.base && size >= 0
|
||
|
f := &File{s, filename, base, size, []int{0}, nil}
|
||
|
base += size + 1 // +1 because EOF also has a position
|
||
|
if base < 0 {
|
||
|
panic("token.Pos offset overflow (> 2G of source code in file set)")
|
||
|
}
|
||
|
// add the file to the file set
|
||
|
s.base = base
|
||
|
s.files = append(s.files, f)
|
||
|
s.last = f
|
||
|
return f
|
||
|
}
|
||
|
|
||
|
// Iterate calls f for the files in the file set in the order they were added
|
||
|
// until f returns false.
|
||
|
//
|
||
|
func (s *FileSet) Iterate(f func(*File) bool) {
|
||
|
for i := 0; ; i++ {
|
||
|
var file *File
|
||
|
s.mutex.RLock()
|
||
|
if i < len(s.files) {
|
||
|
file = s.files[i]
|
||
|
}
|
||
|
s.mutex.RUnlock()
|
||
|
if file == nil || !f(file) {
|
||
|
break
|
||
|
}
|
||
|
}
|
||
|
}
|
||
|
|
||
|
func searchFiles(a []*File, x int) int {
|
||
|
return sort.Search(len(a), func(i int) bool { return a[i].base > x }) - 1
|
||
|
}
|
||
|
|
||
|
func (s *FileSet) file(p Pos) *File {
|
||
|
// common case: p is in last file
|
||
|
if f := s.last; f != nil && f.base <= int(p) && int(p) <= f.base+f.size {
|
||
|
return f
|
||
|
}
|
||
|
// p is not in last file - search all files
|
||
|
if i := searchFiles(s.files, int(p)); i >= 0 {
|
||
|
f := s.files[i]
|
||
|
// f.base <= int(p) by definition of searchFiles
|
||
|
if int(p) <= f.base+f.size {
|
||
|
s.last = f
|
||
|
return f
|
||
|
}
|
||
|
}
|
||
|
return nil
|
||
|
}
|
||
|
|
||
|
// File returns the file that contains the position p.
|
||
|
// If no such file is found (for instance for p == NoPos),
|
||
|
// the result is nil.
|
||
|
//
|
||
|
func (s *FileSet) File(p Pos) (f *File) {
|
||
|
if p != NoPos {
|
||
|
s.mutex.RLock()
|
||
|
f = s.file(p)
|
||
|
s.mutex.RUnlock()
|
||
|
}
|
||
|
return
|
||
|
}
|
||
|
|
||
|
// Position converts a Pos in the fileset into a general Position.
|
||
|
func (s *FileSet) Position(p Pos) (pos Position) {
|
||
|
if p != NoPos {
|
||
|
s.mutex.RLock()
|
||
|
if f := s.file(p); f != nil {
|
||
|
pos = f.position(p)
|
||
|
}
|
||
|
s.mutex.RUnlock()
|
||
|
}
|
||
|
return
|
||
|
}
|
||
|
|
||
|
// -----------------------------------------------------------------------------
|
||
|
// Helper functions
|
||
|
|
||
|
func searchInts(a []int, x int) int {
|
||
|
// This function body is a manually inlined version of:
|
||
|
//
|
||
|
// return sort.Search(len(a), func(i int) bool { return a[i] > x }) - 1
|
||
|
//
|
||
|
// With better compiler optimizations, this may not be needed in the
|
||
|
// future, but at the moment this change improves the go/printer
|
||
|
// benchmark performance by ~30%. This has a direct impact on the
|
||
|
// speed of gofmt and thus seems worthwhile (2011-04-29).
|
||
|
// TODO(gri): Remove this when compilers have caught up.
|
||
|
i, j := 0, len(a)
|
||
|
for i < j {
|
||
|
h := i + (j-i)/2 // avoid overflow when computing h
|
||
|
// i ≤ h < j
|
||
|
if a[h] <= x {
|
||
|
i = h + 1
|
||
|
} else {
|
||
|
j = h
|
||
|
}
|
||
|
}
|
||
|
return i - 1
|
||
|
}
|