/usr/share/gocode/src/gopkg.in/gcfg.v1/token/position.go is in golang-gopkg-gcfg.v1-dev 0.0~git20150907.0.0ef1a85-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 | // 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
}
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