| 1 | // Copyright 2018 The Go Authors. All rights reserved. |
|---|---|
| 2 | // Use of this source code is governed by a BSD-style |
| 3 | // license that can be found in the LICENSE file. |
| 4 | |
| 5 | // Package gopathwalk is like filepath.Walk but specialized for finding Go |
| 6 | // packages, particularly in $GOPATH and $GOROOT. |
| 7 | package gopathwalk |
| 8 | |
| 9 | import ( |
| 10 | "bufio" |
| 11 | "bytes" |
| 12 | "fmt" |
| 13 | "io/ioutil" |
| 14 | "log" |
| 15 | "os" |
| 16 | "path/filepath" |
| 17 | "strings" |
| 18 | "time" |
| 19 | |
| 20 | "golang.org/x/tools/internal/fastwalk" |
| 21 | ) |
| 22 | |
| 23 | // Options controls the behavior of a Walk call. |
| 24 | type Options struct { |
| 25 | // If Logf is non-nil, debug logging is enabled through this function. |
| 26 | Logf func(format string, args ...interface{}) |
| 27 | // Search module caches. Also disables legacy goimports ignore rules. |
| 28 | ModulesEnabled bool |
| 29 | } |
| 30 | |
| 31 | // RootType indicates the type of a Root. |
| 32 | type RootType int |
| 33 | |
| 34 | const ( |
| 35 | RootUnknown RootType = iota |
| 36 | RootGOROOT |
| 37 | RootGOPATH |
| 38 | RootCurrentModule |
| 39 | RootModuleCache |
| 40 | RootOther |
| 41 | ) |
| 42 | |
| 43 | // A Root is a starting point for a Walk. |
| 44 | type Root struct { |
| 45 | Path string |
| 46 | Type RootType |
| 47 | } |
| 48 | |
| 49 | // Walk walks Go source directories ($GOROOT, $GOPATH, etc) to find packages. |
| 50 | // For each package found, add will be called (concurrently) with the absolute |
| 51 | // paths of the containing source directory and the package directory. |
| 52 | // add will be called concurrently. |
| 53 | func Walk(roots []Root, add func(root Root, dir string), opts Options) { |
| 54 | WalkSkip(roots, add, func(Root, string) bool { return false }, opts) |
| 55 | } |
| 56 | |
| 57 | // WalkSkip walks Go source directories ($GOROOT, $GOPATH, etc) to find packages. |
| 58 | // For each package found, add will be called (concurrently) with the absolute |
| 59 | // paths of the containing source directory and the package directory. |
| 60 | // For each directory that will be scanned, skip will be called (concurrently) |
| 61 | // with the absolute paths of the containing source directory and the directory. |
| 62 | // If skip returns false on a directory it will be processed. |
| 63 | // add will be called concurrently. |
| 64 | // skip will be called concurrently. |
| 65 | func WalkSkip(roots []Root, add func(root Root, dir string), skip func(root Root, dir string) bool, opts Options) { |
| 66 | for _, root := range roots { |
| 67 | walkDir(root, add, skip, opts) |
| 68 | } |
| 69 | } |
| 70 | |
| 71 | // walkDir creates a walker and starts fastwalk with this walker. |
| 72 | func walkDir(root Root, add func(Root, string), skip func(root Root, dir string) bool, opts Options) { |
| 73 | if _, err := os.Stat(root.Path); os.IsNotExist(err) { |
| 74 | if opts.Logf != nil { |
| 75 | opts.Logf("skipping nonexistent directory: %v", root.Path) |
| 76 | } |
| 77 | return |
| 78 | } |
| 79 | start := time.Now() |
| 80 | if opts.Logf != nil { |
| 81 | opts.Logf("gopathwalk: scanning %s", root.Path) |
| 82 | } |
| 83 | w := &walker{ |
| 84 | root: root, |
| 85 | add: add, |
| 86 | skip: skip, |
| 87 | opts: opts, |
| 88 | } |
| 89 | w.init() |
| 90 | if err := fastwalk.Walk(root.Path, w.walk); err != nil { |
| 91 | log.Printf("gopathwalk: scanning directory %v: %v", root.Path, err) |
| 92 | } |
| 93 | |
| 94 | if opts.Logf != nil { |
| 95 | opts.Logf("gopathwalk: scanned %s in %v", root.Path, time.Since(start)) |
| 96 | } |
| 97 | } |
| 98 | |
| 99 | // walker is the callback for fastwalk.Walk. |
| 100 | type walker struct { |
| 101 | root Root // The source directory to scan. |
| 102 | add func(Root, string) // The callback that will be invoked for every possible Go package dir. |
| 103 | skip func(Root, string) bool // The callback that will be invoked for every dir. dir is skipped if it returns true. |
| 104 | opts Options // Options passed to Walk by the user. |
| 105 | |
| 106 | ignoredDirs []os.FileInfo // The ignored directories, loaded from .goimportsignore files. |
| 107 | } |
| 108 | |
| 109 | // init initializes the walker based on its Options |
| 110 | func (w *walker) init() { |
| 111 | var ignoredPaths []string |
| 112 | if w.root.Type == RootModuleCache { |
| 113 | ignoredPaths = []string{"cache"} |
| 114 | } |
| 115 | if !w.opts.ModulesEnabled && w.root.Type == RootGOPATH { |
| 116 | ignoredPaths = w.getIgnoredDirs(w.root.Path) |
| 117 | ignoredPaths = append(ignoredPaths, "v", "mod") |
| 118 | } |
| 119 | |
| 120 | for _, p := range ignoredPaths { |
| 121 | full := filepath.Join(w.root.Path, p) |
| 122 | if fi, err := os.Stat(full); err == nil { |
| 123 | w.ignoredDirs = append(w.ignoredDirs, fi) |
| 124 | if w.opts.Logf != nil { |
| 125 | w.opts.Logf("Directory added to ignore list: %s", full) |
| 126 | } |
| 127 | } else if w.opts.Logf != nil { |
| 128 | w.opts.Logf("Error statting ignored directory: %v", err) |
| 129 | } |
| 130 | } |
| 131 | } |
| 132 | |
| 133 | // getIgnoredDirs reads an optional config file at <path>/.goimportsignore |
| 134 | // of relative directories to ignore when scanning for go files. |
| 135 | // The provided path is one of the $GOPATH entries with "src" appended. |
| 136 | func (w *walker) getIgnoredDirs(path string) []string { |
| 137 | file := filepath.Join(path, ".goimportsignore") |
| 138 | slurp, err := ioutil.ReadFile(file) |
| 139 | if w.opts.Logf != nil { |
| 140 | if err != nil { |
| 141 | w.opts.Logf("%v", err) |
| 142 | } else { |
| 143 | w.opts.Logf("Read %s", file) |
| 144 | } |
| 145 | } |
| 146 | if err != nil { |
| 147 | return nil |
| 148 | } |
| 149 | |
| 150 | var ignoredDirs []string |
| 151 | bs := bufio.NewScanner(bytes.NewReader(slurp)) |
| 152 | for bs.Scan() { |
| 153 | line := strings.TrimSpace(bs.Text()) |
| 154 | if line == "" || strings.HasPrefix(line, "#") { |
| 155 | continue |
| 156 | } |
| 157 | ignoredDirs = append(ignoredDirs, line) |
| 158 | } |
| 159 | return ignoredDirs |
| 160 | } |
| 161 | |
| 162 | // shouldSkipDir reports whether the file should be skipped or not. |
| 163 | func (w *walker) shouldSkipDir(fi os.FileInfo, dir string) bool { |
| 164 | for _, ignoredDir := range w.ignoredDirs { |
| 165 | if os.SameFile(fi, ignoredDir) { |
| 166 | return true |
| 167 | } |
| 168 | } |
| 169 | if w.skip != nil { |
| 170 | // Check with the user specified callback. |
| 171 | return w.skip(w.root, dir) |
| 172 | } |
| 173 | return false |
| 174 | } |
| 175 | |
| 176 | // walk walks through the given path. |
| 177 | func (w *walker) walk(path string, typ os.FileMode) error { |
| 178 | if typ.IsRegular() { |
| 179 | dir := filepath.Dir(path) |
| 180 | if dir == w.root.Path && (w.root.Type == RootGOROOT || w.root.Type == RootGOPATH) { |
| 181 | // Doesn't make sense to have regular files |
| 182 | // directly in your $GOPATH/src or $GOROOT/src. |
| 183 | return fastwalk.ErrSkipFiles |
| 184 | } |
| 185 | if !strings.HasSuffix(path, ".go") { |
| 186 | return nil |
| 187 | } |
| 188 | |
| 189 | w.add(w.root, dir) |
| 190 | return fastwalk.ErrSkipFiles |
| 191 | } |
| 192 | if typ == os.ModeDir { |
| 193 | base := filepath.Base(path) |
| 194 | if base == "" || base[0] == '.' || base[0] == '_' || |
| 195 | base == "testdata" || |
| 196 | (w.root.Type == RootGOROOT && w.opts.ModulesEnabled && base == "vendor") || |
| 197 | (!w.opts.ModulesEnabled && base == "node_modules") { |
| 198 | return filepath.SkipDir |
| 199 | } |
| 200 | fi, err := os.Lstat(path) |
| 201 | if err == nil && w.shouldSkipDir(fi, path) { |
| 202 | return filepath.SkipDir |
| 203 | } |
| 204 | return nil |
| 205 | } |
| 206 | if typ == os.ModeSymlink { |
| 207 | base := filepath.Base(path) |
| 208 | if strings.HasPrefix(base, ".#") { |
| 209 | // Emacs noise. |
| 210 | return nil |
| 211 | } |
| 212 | if w.shouldTraverse(path) { |
| 213 | return fastwalk.ErrTraverseLink |
| 214 | } |
| 215 | } |
| 216 | return nil |
| 217 | } |
| 218 | |
| 219 | // shouldTraverse reports whether the symlink fi, found in dir, |
| 220 | // should be followed. It makes sure symlinks were never visited |
| 221 | // before to avoid symlink loops. |
| 222 | func (w *walker) shouldTraverse(path string) bool { |
| 223 | ts, err := os.Stat(path) |
| 224 | if err != nil { |
| 225 | fmt.Fprintln(os.Stderr, err) |
| 226 | return false |
| 227 | } |
| 228 | if !ts.IsDir() { |
| 229 | return false |
| 230 | } |
| 231 | if w.shouldSkipDir(ts, filepath.Dir(path)) { |
| 232 | return false |
| 233 | } |
| 234 | // Check for symlink loops by statting each directory component |
| 235 | // and seeing if any are the same file as ts. |
| 236 | for { |
| 237 | parent := filepath.Dir(path) |
| 238 | if parent == path { |
| 239 | // Made it to the root without seeing a cycle. |
| 240 | // Use this symlink. |
| 241 | return true |
| 242 | } |
| 243 | parentInfo, err := os.Stat(parent) |
| 244 | if err != nil { |
| 245 | return false |
| 246 | } |
| 247 | if os.SameFile(ts, parentInfo) { |
| 248 | // Cycle. Don't traverse. |
| 249 | return false |
| 250 | } |
| 251 | path = parent |
| 252 | } |
| 253 | |
| 254 | } |
| 255 |
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