| 1 | package pathidentity |
| 2 | |
| 3 | import "os" |
| 4 | |
| 5 | // Matcher compares paths under one Options, resolving and statting each |
| 6 | // distinct path once. Identity can change between passes (a directory's case |
| 7 | // flag, a relinked junction), so a Matcher must not outlive the pass using it. |
| 8 | type Matcher struct { |
| 9 | options Options |
| 10 | resolve func(string, Options) (Identity, error) |
| 11 | seen map[string]matchedPath |
| 12 | } |
| 13 | |
| 14 | type matchedPath struct { |
| 15 | identity Identity |
| 16 | err error |
| 17 | info os.FileInfo |
| 18 | statErr error |
| 19 | } |
| 20 | |
| 21 | // NewMatcher uses resolve in place of Resolve when it is non-nil. |
| 22 | func NewMatcher(options Options, resolve func(string, Options) (Identity, error)) *Matcher { |
| 23 | if resolve == nil { |
| 24 | resolve = Resolve |
| 25 | } |
| 26 | return &Matcher{options: options, resolve: resolve, seen: map[string]matchedPath{}} |
| 27 | } |
| 28 | |
| 29 | func (m *Matcher) lookup(path string) matchedPath { |
| 30 | if found, ok := m.seen[path]; ok { |
| 31 | return found |
| 32 | } |
| 33 | var entry matchedPath |
| 34 | entry.identity, entry.err = m.resolve(path, m.options) |
| 35 | if entry.err == nil { |
| 36 | entry.info, entry.statErr = statForMode(entry.identity.AccessPath, m.options.FollowLeaf) |
| 37 | } |
| 38 | m.seen[path] = entry |
| 39 | return entry |
| 40 | } |
| 41 | |
| 42 | func (m *Matcher) Same(a, b string) (bool, error) { |
| 43 | left := m.lookup(a) |
| 44 | if left.err != nil { |
| 45 | return false, left.err |
| 46 | } |
| 47 | right := m.lookup(b) |
| 48 | if right.err != nil { |
| 49 | return false, right.err |
| 50 | } |
| 51 | if left.statErr == nil && right.statErr == nil && os.SameFile(left.info, right.info) { |
| 52 | return true, nil |
| 53 | } |
| 54 | for _, statErr := range []error{left.statErr, right.statErr} { |
| 55 | if statErr != nil && !os.IsNotExist(statErr) { |
| 56 | return false, classify("verify", "", statErr) |
| 57 | } |
| 58 | } |
| 59 | return left.identity.Key == right.identity.Key, nil |
| 60 | } |
| 61 |