Colin Cross | 1f80552 | 2021-05-14 11:10:59 -0700 | [diff] [blame] | 1 | // Package fsys is an abstraction for reading files that |
| 2 | // allows for virtual overlays on top of the files on disk. |
| 3 | package fsys |
| 4 | |
| 5 | import ( |
| 6 | "encoding/json" |
| 7 | "errors" |
| 8 | "fmt" |
| 9 | "io/fs" |
| 10 | "io/ioutil" |
| 11 | "os" |
| 12 | "path/filepath" |
| 13 | "runtime" |
| 14 | "sort" |
| 15 | "strings" |
| 16 | "time" |
| 17 | ) |
| 18 | |
| 19 | // OverlayFile is the path to a text file in the OverlayJSON format. |
| 20 | // It is the value of the -overlay flag. |
| 21 | var OverlayFile string |
| 22 | |
| 23 | // OverlayJSON is the format overlay files are expected to be in. |
| 24 | // The Replace map maps from overlaid paths to replacement paths: |
| 25 | // the Go command will forward all reads trying to open |
| 26 | // each overlaid path to its replacement path, or consider the overlaid |
| 27 | // path not to exist if the replacement path is empty. |
| 28 | type OverlayJSON struct { |
| 29 | Replace map[string]string |
| 30 | } |
| 31 | |
| 32 | type node struct { |
| 33 | actualFilePath string // empty if a directory |
| 34 | children map[string]*node // path element → file or directory |
| 35 | } |
| 36 | |
| 37 | func (n *node) isDir() bool { |
| 38 | return n.actualFilePath == "" && n.children != nil |
| 39 | } |
| 40 | |
| 41 | func (n *node) isDeleted() bool { |
| 42 | return n.actualFilePath == "" && n.children == nil |
| 43 | } |
| 44 | |
| 45 | // TODO(matloob): encapsulate these in an io/fs-like interface |
| 46 | var overlay map[string]*node // path -> file or directory node |
Dan Willemsen | cc753b7 | 2021-08-31 13:25:42 -0700 | [diff] [blame] | 47 | var cwd string // copy of base.Cwd() to avoid dependency |
Colin Cross | 1f80552 | 2021-05-14 11:10:59 -0700 | [diff] [blame] | 48 | |
| 49 | // Canonicalize a path for looking it up in the overlay. |
| 50 | // Important: filepath.Join(cwd, path) doesn't always produce |
| 51 | // the correct absolute path if path is relative, because on |
| 52 | // Windows producing the correct absolute path requires making |
| 53 | // a syscall. So this should only be used when looking up paths |
| 54 | // in the overlay, or canonicalizing the paths in the overlay. |
| 55 | func canonicalize(path string) string { |
| 56 | if path == "" { |
| 57 | return "" |
| 58 | } |
| 59 | if filepath.IsAbs(path) { |
| 60 | return filepath.Clean(path) |
| 61 | } |
| 62 | |
| 63 | if v := filepath.VolumeName(cwd); v != "" && path[0] == filepath.Separator { |
| 64 | // On Windows filepath.Join(cwd, path) doesn't always work. In general |
| 65 | // filepath.Abs needs to make a syscall on Windows. Elsewhere in cmd/go |
| 66 | // use filepath.Join(cwd, path), but cmd/go specifically supports Windows |
| 67 | // paths that start with "\" which implies the path is relative to the |
| 68 | // volume of the working directory. See golang.org/issue/8130. |
| 69 | return filepath.Join(v, path) |
| 70 | } |
| 71 | |
| 72 | // Make the path absolute. |
| 73 | return filepath.Join(cwd, path) |
| 74 | } |
| 75 | |
| 76 | // Init initializes the overlay, if one is being used. |
| 77 | func Init(wd string) error { |
| 78 | if overlay != nil { |
| 79 | // already initialized |
| 80 | return nil |
| 81 | } |
| 82 | |
| 83 | cwd = wd |
| 84 | |
| 85 | if OverlayFile == "" { |
| 86 | return nil |
| 87 | } |
| 88 | |
| 89 | b, err := os.ReadFile(OverlayFile) |
| 90 | if err != nil { |
| 91 | return fmt.Errorf("reading overlay file: %v", err) |
| 92 | } |
| 93 | |
| 94 | var overlayJSON OverlayJSON |
| 95 | if err := json.Unmarshal(b, &overlayJSON); err != nil { |
| 96 | return fmt.Errorf("parsing overlay JSON: %v", err) |
| 97 | } |
| 98 | |
| 99 | return initFromJSON(overlayJSON) |
| 100 | } |
| 101 | |
| 102 | func initFromJSON(overlayJSON OverlayJSON) error { |
Dan Willemsen | cc753b7 | 2021-08-31 13:25:42 -0700 | [diff] [blame] | 103 | // Canonicalize the paths in the overlay map. |
Colin Cross | 1f80552 | 2021-05-14 11:10:59 -0700 | [diff] [blame] | 104 | // Use reverseCanonicalized to check for collisions: |
| 105 | // no two 'from' paths should canonicalize to the same path. |
| 106 | overlay = make(map[string]*node) |
| 107 | reverseCanonicalized := make(map[string]string) // inverse of canonicalize operation, to check for duplicates |
| 108 | // Build a table of file and directory nodes from the replacement map. |
| 109 | |
| 110 | // Remove any potential non-determinism from iterating over map by sorting it. |
| 111 | replaceFrom := make([]string, 0, len(overlayJSON.Replace)) |
| 112 | for k := range overlayJSON.Replace { |
| 113 | replaceFrom = append(replaceFrom, k) |
| 114 | } |
| 115 | sort.Strings(replaceFrom) |
| 116 | |
| 117 | for _, from := range replaceFrom { |
| 118 | to := overlayJSON.Replace[from] |
| 119 | // Canonicalize paths and check for a collision. |
| 120 | if from == "" { |
| 121 | return fmt.Errorf("empty string key in overlay file Replace map") |
| 122 | } |
| 123 | cfrom := canonicalize(from) |
| 124 | if to != "" { |
| 125 | // Don't canonicalize "", meaning to delete a file, because then it will turn into ".". |
| 126 | to = canonicalize(to) |
| 127 | } |
| 128 | if otherFrom, seen := reverseCanonicalized[cfrom]; seen { |
| 129 | return fmt.Errorf( |
| 130 | "paths %q and %q both canonicalize to %q in overlay file Replace map", otherFrom, from, cfrom) |
| 131 | } |
| 132 | reverseCanonicalized[cfrom] = from |
| 133 | from = cfrom |
| 134 | |
| 135 | // Create node for overlaid file. |
| 136 | dir, base := filepath.Dir(from), filepath.Base(from) |
| 137 | if n, ok := overlay[from]; ok { |
| 138 | // All 'from' paths in the overlay are file paths. Since the from paths |
| 139 | // are in a map, they are unique, so if the node already exists we added |
| 140 | // it below when we create parent directory nodes. That is, that |
| 141 | // both a file and a path to one of its parent directories exist as keys |
| 142 | // in the Replace map. |
| 143 | // |
| 144 | // This only applies if the overlay directory has any files or directories |
| 145 | // in it: placeholder directories that only contain deleted files don't |
| 146 | // count. They are safe to be overwritten with actual files. |
| 147 | for _, f := range n.children { |
| 148 | if !f.isDeleted() { |
| 149 | return fmt.Errorf("invalid overlay: path %v is used as both file and directory", from) |
| 150 | } |
| 151 | } |
| 152 | } |
| 153 | overlay[from] = &node{actualFilePath: to} |
| 154 | |
| 155 | // Add parent directory nodes to overlay structure. |
| 156 | childNode := overlay[from] |
| 157 | for { |
| 158 | dirNode := overlay[dir] |
| 159 | if dirNode == nil || dirNode.isDeleted() { |
| 160 | dirNode = &node{children: make(map[string]*node)} |
| 161 | overlay[dir] = dirNode |
| 162 | } |
| 163 | if childNode.isDeleted() { |
| 164 | // Only create one parent for a deleted file: |
| 165 | // the directory only conditionally exists if |
| 166 | // there are any non-deleted children, so |
| 167 | // we don't create their parents. |
| 168 | if dirNode.isDir() { |
| 169 | dirNode.children[base] = childNode |
| 170 | } |
| 171 | break |
| 172 | } |
| 173 | if !dirNode.isDir() { |
| 174 | // This path already exists as a file, so it can't be a parent |
| 175 | // directory. See comment at error above. |
| 176 | return fmt.Errorf("invalid overlay: path %v is used as both file and directory", dir) |
| 177 | } |
| 178 | dirNode.children[base] = childNode |
| 179 | parent := filepath.Dir(dir) |
| 180 | if parent == dir { |
| 181 | break // reached the top; there is no parent |
| 182 | } |
| 183 | dir, base = parent, filepath.Base(dir) |
| 184 | childNode = dirNode |
| 185 | } |
| 186 | } |
| 187 | |
| 188 | return nil |
| 189 | } |
| 190 | |
| 191 | // IsDir returns true if path is a directory on disk or in the |
| 192 | // overlay. |
| 193 | func IsDir(path string) (bool, error) { |
| 194 | path = canonicalize(path) |
| 195 | |
| 196 | if _, ok := parentIsOverlayFile(path); ok { |
| 197 | return false, nil |
| 198 | } |
| 199 | |
| 200 | if n, ok := overlay[path]; ok { |
| 201 | return n.isDir(), nil |
| 202 | } |
| 203 | |
| 204 | fi, err := os.Stat(path) |
| 205 | if err != nil { |
| 206 | return false, err |
| 207 | } |
| 208 | |
| 209 | return fi.IsDir(), nil |
| 210 | } |
| 211 | |
| 212 | // parentIsOverlayFile returns whether name or any of |
| 213 | // its parents are files in the overlay, and the first parent found, |
| 214 | // including name itself, that's a file in the overlay. |
| 215 | func parentIsOverlayFile(name string) (string, bool) { |
| 216 | if overlay != nil { |
| 217 | // Check if name can't possibly be a directory because |
| 218 | // it or one of its parents is overlaid with a file. |
| 219 | // TODO(matloob): Maybe save this to avoid doing it every time? |
| 220 | prefix := name |
| 221 | for { |
| 222 | node := overlay[prefix] |
| 223 | if node != nil && !node.isDir() { |
| 224 | return prefix, true |
| 225 | } |
| 226 | parent := filepath.Dir(prefix) |
| 227 | if parent == prefix { |
| 228 | break |
| 229 | } |
| 230 | prefix = parent |
| 231 | } |
| 232 | } |
| 233 | |
| 234 | return "", false |
| 235 | } |
| 236 | |
| 237 | // errNotDir is used to communicate from ReadDir to IsDirWithGoFiles |
| 238 | // that the argument is not a directory, so that IsDirWithGoFiles doesn't |
| 239 | // return an error. |
| 240 | var errNotDir = errors.New("not a directory") |
| 241 | |
| 242 | // readDir reads a dir on disk, returning an error that is errNotDir if the dir is not a directory. |
| 243 | // Unfortunately, the error returned by ioutil.ReadDir if dir is not a directory |
| 244 | // can vary depending on the OS (Linux, Mac, Windows return ENOTDIR; BSD returns EINVAL). |
| 245 | func readDir(dir string) ([]fs.FileInfo, error) { |
| 246 | fis, err := ioutil.ReadDir(dir) |
| 247 | if err == nil { |
| 248 | return fis, nil |
| 249 | } |
| 250 | |
| 251 | if os.IsNotExist(err) { |
| 252 | return nil, err |
| 253 | } |
| 254 | if dirfi, staterr := os.Stat(dir); staterr == nil && !dirfi.IsDir() { |
| 255 | return nil, &fs.PathError{Op: "ReadDir", Path: dir, Err: errNotDir} |
| 256 | } |
| 257 | return nil, err |
| 258 | } |
| 259 | |
| 260 | // ReadDir provides a slice of fs.FileInfo entries corresponding |
| 261 | // to the overlaid files in the directory. |
| 262 | func ReadDir(dir string) ([]fs.FileInfo, error) { |
| 263 | dir = canonicalize(dir) |
| 264 | if _, ok := parentIsOverlayFile(dir); ok { |
| 265 | return nil, &fs.PathError{Op: "ReadDir", Path: dir, Err: errNotDir} |
| 266 | } |
| 267 | |
| 268 | dirNode := overlay[dir] |
| 269 | if dirNode == nil { |
| 270 | return readDir(dir) |
| 271 | } |
| 272 | if dirNode.isDeleted() { |
| 273 | return nil, &fs.PathError{Op: "ReadDir", Path: dir, Err: fs.ErrNotExist} |
| 274 | } |
| 275 | diskfis, err := readDir(dir) |
| 276 | if err != nil && !os.IsNotExist(err) && !errors.Is(err, errNotDir) { |
| 277 | return nil, err |
| 278 | } |
| 279 | |
| 280 | // Stat files in overlay to make composite list of fileinfos |
| 281 | files := make(map[string]fs.FileInfo) |
| 282 | for _, f := range diskfis { |
| 283 | files[f.Name()] = f |
| 284 | } |
| 285 | for name, to := range dirNode.children { |
| 286 | switch { |
| 287 | case to.isDir(): |
| 288 | files[name] = fakeDir(name) |
| 289 | case to.isDeleted(): |
| 290 | delete(files, name) |
| 291 | default: |
| 292 | // This is a regular file. |
| 293 | f, err := os.Lstat(to.actualFilePath) |
| 294 | if err != nil { |
| 295 | files[name] = missingFile(name) |
| 296 | continue |
| 297 | } else if f.IsDir() { |
| 298 | return nil, fmt.Errorf("for overlay of %q to %q: overlay Replace entries can't point to dirctories", |
| 299 | filepath.Join(dir, name), to.actualFilePath) |
| 300 | } |
| 301 | // Add a fileinfo for the overlaid file, so that it has |
| 302 | // the original file's name, but the overlaid file's metadata. |
| 303 | files[name] = fakeFile{name, f} |
| 304 | } |
| 305 | } |
| 306 | sortedFiles := diskfis[:0] |
| 307 | for _, f := range files { |
| 308 | sortedFiles = append(sortedFiles, f) |
| 309 | } |
| 310 | sort.Slice(sortedFiles, func(i, j int) bool { return sortedFiles[i].Name() < sortedFiles[j].Name() }) |
| 311 | return sortedFiles, nil |
| 312 | } |
| 313 | |
| 314 | // OverlayPath returns the path to the overlaid contents of the |
| 315 | // file, the empty string if the overlay deletes the file, or path |
| 316 | // itself if the file is not in the overlay, the file is a directory |
| 317 | // in the overlay, or there is no overlay. |
| 318 | // It returns true if the path is overlaid with a regular file |
| 319 | // or deleted, and false otherwise. |
| 320 | func OverlayPath(path string) (string, bool) { |
| 321 | if p, ok := overlay[canonicalize(path)]; ok && !p.isDir() { |
| 322 | return p.actualFilePath, ok |
| 323 | } |
| 324 | |
| 325 | return path, false |
| 326 | } |
| 327 | |
| 328 | // Open opens the file at or overlaid on the given path. |
| 329 | func Open(path string) (*os.File, error) { |
| 330 | return OpenFile(path, os.O_RDONLY, 0) |
| 331 | } |
| 332 | |
| 333 | // OpenFile opens the file at or overlaid on the given path with the flag and perm. |
| 334 | func OpenFile(path string, flag int, perm os.FileMode) (*os.File, error) { |
| 335 | cpath := canonicalize(path) |
| 336 | if node, ok := overlay[cpath]; ok { |
| 337 | // Opening a file in the overlay. |
| 338 | if node.isDir() { |
| 339 | return nil, &fs.PathError{Op: "OpenFile", Path: path, Err: errors.New("fsys.OpenFile doesn't support opening directories yet")} |
| 340 | } |
| 341 | // We can't open overlaid paths for write. |
| 342 | if perm != os.FileMode(os.O_RDONLY) { |
| 343 | return nil, &fs.PathError{Op: "OpenFile", Path: path, Err: errors.New("overlaid files can't be opened for write")} |
| 344 | } |
| 345 | return os.OpenFile(node.actualFilePath, flag, perm) |
| 346 | } |
| 347 | if parent, ok := parentIsOverlayFile(filepath.Dir(cpath)); ok { |
| 348 | // The file is deleted explicitly in the Replace map, |
| 349 | // or implicitly because one of its parent directories was |
| 350 | // replaced by a file. |
| 351 | return nil, &fs.PathError{ |
| 352 | Op: "Open", |
| 353 | Path: path, |
| 354 | Err: fmt.Errorf("file %s does not exist: parent directory %s is replaced by a file in overlay", path, parent), |
| 355 | } |
| 356 | } |
| 357 | return os.OpenFile(cpath, flag, perm) |
| 358 | } |
| 359 | |
| 360 | // IsDirWithGoFiles reports whether dir is a directory containing Go files |
| 361 | // either on disk or in the overlay. |
| 362 | func IsDirWithGoFiles(dir string) (bool, error) { |
| 363 | fis, err := ReadDir(dir) |
| 364 | if os.IsNotExist(err) || errors.Is(err, errNotDir) { |
| 365 | return false, nil |
| 366 | } |
| 367 | if err != nil { |
| 368 | return false, err |
| 369 | } |
| 370 | |
| 371 | var firstErr error |
| 372 | for _, fi := range fis { |
| 373 | if fi.IsDir() { |
| 374 | continue |
| 375 | } |
| 376 | |
| 377 | // TODO(matloob): this enforces that the "from" in the map |
| 378 | // has a .go suffix, but the actual destination file |
| 379 | // doesn't need to have a .go suffix. Is this okay with the |
| 380 | // compiler? |
| 381 | if !strings.HasSuffix(fi.Name(), ".go") { |
| 382 | continue |
| 383 | } |
| 384 | if fi.Mode().IsRegular() { |
| 385 | return true, nil |
| 386 | } |
| 387 | |
| 388 | // fi is the result of an Lstat, so it doesn't follow symlinks. |
| 389 | // But it's okay if the file is a symlink pointing to a regular |
| 390 | // file, so use os.Stat to follow symlinks and check that. |
| 391 | actualFilePath, _ := OverlayPath(filepath.Join(dir, fi.Name())) |
| 392 | fi, err := os.Stat(actualFilePath) |
| 393 | if err == nil && fi.Mode().IsRegular() { |
| 394 | return true, nil |
| 395 | } |
| 396 | if err != nil && firstErr == nil { |
| 397 | firstErr = err |
| 398 | } |
| 399 | } |
| 400 | |
| 401 | // No go files found in directory. |
| 402 | return false, firstErr |
| 403 | } |
| 404 | |
| 405 | // walk recursively descends path, calling walkFn. Copied, with some |
| 406 | // modifications from path/filepath.walk. |
| 407 | func walk(path string, info fs.FileInfo, walkFn filepath.WalkFunc) error { |
| 408 | if !info.IsDir() { |
| 409 | return walkFn(path, info, nil) |
| 410 | } |
| 411 | |
| 412 | fis, readErr := ReadDir(path) |
| 413 | walkErr := walkFn(path, info, readErr) |
| 414 | // If readErr != nil, walk can't walk into this directory. |
| 415 | // walkErr != nil means walkFn want walk to skip this directory or stop walking. |
| 416 | // Therefore, if one of readErr and walkErr isn't nil, walk will return. |
| 417 | if readErr != nil || walkErr != nil { |
| 418 | // The caller's behavior is controlled by the return value, which is decided |
| 419 | // by walkFn. walkFn may ignore readErr and return nil. |
| 420 | // If walkFn returns SkipDir, it will be handled by the caller. |
| 421 | // So walk should return whatever walkFn returns. |
| 422 | return walkErr |
| 423 | } |
| 424 | |
| 425 | for _, fi := range fis { |
| 426 | filename := filepath.Join(path, fi.Name()) |
| 427 | if walkErr = walk(filename, fi, walkFn); walkErr != nil { |
| 428 | if !fi.IsDir() || walkErr != filepath.SkipDir { |
| 429 | return walkErr |
| 430 | } |
| 431 | } |
| 432 | } |
| 433 | return nil |
| 434 | } |
| 435 | |
| 436 | // Walk walks the file tree rooted at root, calling walkFn for each file or |
| 437 | // directory in the tree, including root. |
| 438 | func Walk(root string, walkFn filepath.WalkFunc) error { |
| 439 | info, err := Lstat(root) |
| 440 | if err != nil { |
| 441 | err = walkFn(root, nil, err) |
| 442 | } else { |
| 443 | err = walk(root, info, walkFn) |
| 444 | } |
| 445 | if err == filepath.SkipDir { |
| 446 | return nil |
| 447 | } |
| 448 | return err |
| 449 | } |
| 450 | |
| 451 | // lstat implements a version of os.Lstat that operates on the overlay filesystem. |
| 452 | func Lstat(path string) (fs.FileInfo, error) { |
| 453 | return overlayStat(path, os.Lstat, "lstat") |
| 454 | } |
| 455 | |
| 456 | // Stat implements a version of os.Stat that operates on the overlay filesystem. |
| 457 | func Stat(path string) (fs.FileInfo, error) { |
| 458 | return overlayStat(path, os.Stat, "stat") |
| 459 | } |
| 460 | |
| 461 | // overlayStat implements lstat or Stat (depending on whether os.Lstat or os.Stat is passed in). |
| 462 | func overlayStat(path string, osStat func(string) (fs.FileInfo, error), opName string) (fs.FileInfo, error) { |
| 463 | cpath := canonicalize(path) |
| 464 | |
| 465 | if _, ok := parentIsOverlayFile(filepath.Dir(cpath)); ok { |
| 466 | return nil, &fs.PathError{Op: opName, Path: cpath, Err: fs.ErrNotExist} |
| 467 | } |
| 468 | |
| 469 | node, ok := overlay[cpath] |
| 470 | if !ok { |
| 471 | // The file or directory is not overlaid. |
| 472 | return osStat(path) |
| 473 | } |
| 474 | |
| 475 | switch { |
| 476 | case node.isDeleted(): |
| 477 | return nil, &fs.PathError{Op: "lstat", Path: cpath, Err: fs.ErrNotExist} |
| 478 | case node.isDir(): |
| 479 | return fakeDir(filepath.Base(path)), nil |
| 480 | default: |
| 481 | fi, err := osStat(node.actualFilePath) |
| 482 | if err != nil { |
| 483 | return nil, err |
| 484 | } |
| 485 | return fakeFile{name: filepath.Base(path), real: fi}, nil |
| 486 | } |
| 487 | } |
| 488 | |
| 489 | // fakeFile provides an fs.FileInfo implementation for an overlaid file, |
| 490 | // so that the file has the name of the overlaid file, but takes all |
| 491 | // other characteristics of the replacement file. |
| 492 | type fakeFile struct { |
| 493 | name string |
| 494 | real fs.FileInfo |
| 495 | } |
| 496 | |
| 497 | func (f fakeFile) Name() string { return f.name } |
| 498 | func (f fakeFile) Size() int64 { return f.real.Size() } |
| 499 | func (f fakeFile) Mode() fs.FileMode { return f.real.Mode() } |
| 500 | func (f fakeFile) ModTime() time.Time { return f.real.ModTime() } |
| 501 | func (f fakeFile) IsDir() bool { return f.real.IsDir() } |
Dan Willemsen | bc60c3c | 2021-12-15 01:09:00 -0800 | [diff] [blame] | 502 | func (f fakeFile) Sys() any { return f.real.Sys() } |
Colin Cross | 1f80552 | 2021-05-14 11:10:59 -0700 | [diff] [blame] | 503 | |
| 504 | // missingFile provides an fs.FileInfo for an overlaid file where the |
| 505 | // destination file in the overlay doesn't exist. It returns zero values |
| 506 | // for the fileInfo methods other than Name, set to the file's name, and Mode |
| 507 | // set to ModeIrregular. |
| 508 | type missingFile string |
| 509 | |
| 510 | func (f missingFile) Name() string { return string(f) } |
| 511 | func (f missingFile) Size() int64 { return 0 } |
| 512 | func (f missingFile) Mode() fs.FileMode { return fs.ModeIrregular } |
| 513 | func (f missingFile) ModTime() time.Time { return time.Unix(0, 0) } |
| 514 | func (f missingFile) IsDir() bool { return false } |
Dan Willemsen | bc60c3c | 2021-12-15 01:09:00 -0800 | [diff] [blame] | 515 | func (f missingFile) Sys() any { return nil } |
Colin Cross | 1f80552 | 2021-05-14 11:10:59 -0700 | [diff] [blame] | 516 | |
| 517 | // fakeDir provides an fs.FileInfo implementation for directories that are |
| 518 | // implicitly created by overlaid files. Each directory in the |
| 519 | // path of an overlaid file is considered to exist in the overlay filesystem. |
| 520 | type fakeDir string |
| 521 | |
| 522 | func (f fakeDir) Name() string { return string(f) } |
| 523 | func (f fakeDir) Size() int64 { return 0 } |
| 524 | func (f fakeDir) Mode() fs.FileMode { return fs.ModeDir | 0500 } |
| 525 | func (f fakeDir) ModTime() time.Time { return time.Unix(0, 0) } |
| 526 | func (f fakeDir) IsDir() bool { return true } |
Dan Willemsen | bc60c3c | 2021-12-15 01:09:00 -0800 | [diff] [blame] | 527 | func (f fakeDir) Sys() any { return nil } |
Colin Cross | 1f80552 | 2021-05-14 11:10:59 -0700 | [diff] [blame] | 528 | |
| 529 | // Glob is like filepath.Glob but uses the overlay file system. |
| 530 | func Glob(pattern string) (matches []string, err error) { |
| 531 | // Check pattern is well-formed. |
| 532 | if _, err := filepath.Match(pattern, ""); err != nil { |
| 533 | return nil, err |
| 534 | } |
| 535 | if !hasMeta(pattern) { |
| 536 | if _, err = Lstat(pattern); err != nil { |
| 537 | return nil, nil |
| 538 | } |
| 539 | return []string{pattern}, nil |
| 540 | } |
| 541 | |
| 542 | dir, file := filepath.Split(pattern) |
| 543 | volumeLen := 0 |
| 544 | if runtime.GOOS == "windows" { |
| 545 | volumeLen, dir = cleanGlobPathWindows(dir) |
| 546 | } else { |
| 547 | dir = cleanGlobPath(dir) |
| 548 | } |
| 549 | |
| 550 | if !hasMeta(dir[volumeLen:]) { |
| 551 | return glob(dir, file, nil) |
| 552 | } |
| 553 | |
| 554 | // Prevent infinite recursion. See issue 15879. |
| 555 | if dir == pattern { |
| 556 | return nil, filepath.ErrBadPattern |
| 557 | } |
| 558 | |
| 559 | var m []string |
| 560 | m, err = Glob(dir) |
| 561 | if err != nil { |
| 562 | return |
| 563 | } |
| 564 | for _, d := range m { |
| 565 | matches, err = glob(d, file, matches) |
| 566 | if err != nil { |
| 567 | return |
| 568 | } |
| 569 | } |
| 570 | return |
| 571 | } |
| 572 | |
| 573 | // cleanGlobPath prepares path for glob matching. |
| 574 | func cleanGlobPath(path string) string { |
| 575 | switch path { |
| 576 | case "": |
| 577 | return "." |
| 578 | case string(filepath.Separator): |
| 579 | // do nothing to the path |
| 580 | return path |
| 581 | default: |
| 582 | return path[0 : len(path)-1] // chop off trailing separator |
| 583 | } |
| 584 | } |
| 585 | |
| 586 | func volumeNameLen(path string) int { |
| 587 | isSlash := func(c uint8) bool { |
| 588 | return c == '\\' || c == '/' |
| 589 | } |
| 590 | if len(path) < 2 { |
| 591 | return 0 |
| 592 | } |
| 593 | // with drive letter |
| 594 | c := path[0] |
| 595 | if path[1] == ':' && ('a' <= c && c <= 'z' || 'A' <= c && c <= 'Z') { |
| 596 | return 2 |
| 597 | } |
| 598 | // is it UNC? https://msdn.microsoft.com/en-us/library/windows/desktop/aa365247(v=vs.85).aspx |
| 599 | if l := len(path); l >= 5 && isSlash(path[0]) && isSlash(path[1]) && |
| 600 | !isSlash(path[2]) && path[2] != '.' { |
| 601 | // first, leading `\\` and next shouldn't be `\`. its server name. |
| 602 | for n := 3; n < l-1; n++ { |
| 603 | // second, next '\' shouldn't be repeated. |
| 604 | if isSlash(path[n]) { |
| 605 | n++ |
| 606 | // third, following something characters. its share name. |
| 607 | if !isSlash(path[n]) { |
| 608 | if path[n] == '.' { |
| 609 | break |
| 610 | } |
| 611 | for ; n < l; n++ { |
| 612 | if isSlash(path[n]) { |
| 613 | break |
| 614 | } |
| 615 | } |
| 616 | return n |
| 617 | } |
| 618 | break |
| 619 | } |
| 620 | } |
| 621 | } |
| 622 | return 0 |
| 623 | } |
| 624 | |
| 625 | // cleanGlobPathWindows is windows version of cleanGlobPath. |
| 626 | func cleanGlobPathWindows(path string) (prefixLen int, cleaned string) { |
| 627 | vollen := volumeNameLen(path) |
| 628 | switch { |
| 629 | case path == "": |
| 630 | return 0, "." |
| 631 | case vollen+1 == len(path) && os.IsPathSeparator(path[len(path)-1]): // /, \, C:\ and C:/ |
| 632 | // do nothing to the path |
| 633 | return vollen + 1, path |
| 634 | case vollen == len(path) && len(path) == 2: // C: |
| 635 | return vollen, path + "." // convert C: into C:. |
| 636 | default: |
| 637 | if vollen >= len(path) { |
| 638 | vollen = len(path) - 1 |
| 639 | } |
| 640 | return vollen, path[0 : len(path)-1] // chop off trailing separator |
| 641 | } |
| 642 | } |
| 643 | |
| 644 | // glob searches for files matching pattern in the directory dir |
| 645 | // and appends them to matches. If the directory cannot be |
| 646 | // opened, it returns the existing matches. New matches are |
| 647 | // added in lexicographical order. |
| 648 | func glob(dir, pattern string, matches []string) (m []string, e error) { |
| 649 | m = matches |
| 650 | fi, err := Stat(dir) |
| 651 | if err != nil { |
| 652 | return // ignore I/O error |
| 653 | } |
| 654 | if !fi.IsDir() { |
| 655 | return // ignore I/O error |
| 656 | } |
| 657 | |
| 658 | list, err := ReadDir(dir) |
| 659 | if err != nil { |
| 660 | return // ignore I/O error |
| 661 | } |
| 662 | |
| 663 | var names []string |
| 664 | for _, info := range list { |
| 665 | names = append(names, info.Name()) |
| 666 | } |
| 667 | sort.Strings(names) |
| 668 | |
| 669 | for _, n := range names { |
| 670 | matched, err := filepath.Match(pattern, n) |
| 671 | if err != nil { |
| 672 | return m, err |
| 673 | } |
| 674 | if matched { |
| 675 | m = append(m, filepath.Join(dir, n)) |
| 676 | } |
| 677 | } |
| 678 | return |
| 679 | } |
| 680 | |
| 681 | // hasMeta reports whether path contains any of the magic characters |
| 682 | // recognized by filepath.Match. |
| 683 | func hasMeta(path string) bool { |
| 684 | magicChars := `*?[` |
| 685 | if runtime.GOOS != "windows" { |
| 686 | magicChars = `*?[\` |
| 687 | } |
| 688 | return strings.ContainsAny(path, magicChars) |
| 689 | } |