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brianquinlanbrianquinlan
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Add support for same on POSIX (#211)
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‎pkgs/io_file/README.md

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@@ -23,7 +23,7 @@ See
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| enum dir contents | | | | | | | |
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| exists | | | | | | | |
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| get metadata (stat) | | | | | | | |
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| identity (same file) | | | | | | | |
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| identity (same file) | | ✓ | ✓ | ✓ | | | |
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| open | | | | | | | |
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| read file (bytes) | | ✓ | ✓ | ✓ | ✓ | | |
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| read file (lines) | | | | | | | |

‎pkgs/io_file/lib/src/file_system.dart

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@@ -34,6 +34,17 @@ class WriteMode {
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/// An abstract representation of a file system.
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base class FileSystem {
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/// Checks whether two paths refer to the same object in the file system.
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///
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/// Throws `PathNotFoundException` if either path doesn't exist.
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///
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/// Links are resolved before determining if the paths refer to the same
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/// object. Throws `PathNotFoundException` if either path requires resolving
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/// a broken link.
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bool same(String path1, String path2) {
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throw UnsupportedError('same');
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}
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/// Create a directory at the given path.
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///
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/// If the directory already exists, then `PathExistsException` is thrown.

‎pkgs/io_file/lib/src/vm_posix_file_system.dart

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@@ -60,6 +60,23 @@ external int write(int fd, Pointer<Uint8> buf, int count);
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/// A [FileSystem] implementation for POSIX systems (e.g. Android, iOS, Linux,
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/// macOS).
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base class PosixFileSystem extends FileSystem {
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@override
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bool same(String path1, String path2) {
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final stat1 = stdlibc.stat(path1);
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if (stat1 == null) {
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final errno = stdlibc.errno;
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throw _getError(errno, 'stat failed', path1);
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}
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final stat2 = stdlibc.stat(path2);
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if (stat2 == null) {
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final errno = stdlibc.errno;
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throw _getError(errno, 'stat failed', path2);
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}
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return (stat1.st_ino == stat2.st_ino) && (stat1.st_dev == stat2.st_dev);
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}
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6380
@override
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void createDirectory(String path) {
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if (stdlibc.mkdir(path, _defaultDirectoryMode) == -1) {

‎pkgs/io_file/test/same_test.dart

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Original file line numberDiff line numberDiff line change
@@ -0,0 +1,232 @@
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// Copyright (c) 2025, the Dart project authors. Please see the AUTHORS file
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// for details. All rights reserved. Use of this source code is governed by a
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// BSD-style license that can be found in the LICENSE file.
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@TestOn('posix')
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library;
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import 'dart:io';
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import 'package:io_file/io_file.dart';
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import 'package:stdlibc/stdlibc.dart' as stdlibc;
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import 'package:test/test.dart';
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import 'test_utils.dart';
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void main() {
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group('same', () {
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late String tmp;
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late Directory cwd;
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setUp(() {
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tmp = createTemp('same');
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cwd = Directory.current;
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});
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tearDown(() {
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Directory.current = cwd;
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deleteTemp(tmp);
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});
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//TODO(brianquinlan): test with a very long path.
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test('path1 does not exist', () {
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final path1 = '$tmp/file1';
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final path2 = '$tmp/file2';
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File(path2).writeAsStringSync('Hello World');
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expect(
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() => fileSystem.same(path1, path2),
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throwsA(
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isA<PathNotFoundException>()
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.having((e) => e.message, 'message', 'stat failed')
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.having((e) => e.path, 'path', path1)
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.having((e) => e.osError?.errorCode, 'errorCode', stdlibc.ENOENT),
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),
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);
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});
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test('path2 does not exist', () {
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final path1 = '$tmp/file1';
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final path2 = '$tmp/file2';
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File(path1).writeAsStringSync('Hello World');
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expect(
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() => fileSystem.same(path1, path2),
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throwsA(
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isA<PathNotFoundException>()
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.having((e) => e.message, 'message', 'stat failed')
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.having((e) => e.path, 'path', path2)
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.having((e) => e.osError?.errorCode, 'errorCode', stdlibc.ENOENT),
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),
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);
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});
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test('path1 and path2 same, do not exist', () {
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final path1 = '$tmp/file1';
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final path2 = '$tmp/file1';
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expect(
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() => fileSystem.same(path1, path2),
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throwsA(
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isA<PathNotFoundException>()
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.having((e) => e.message, 'message', 'stat failed')
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.having((e) => e.path, 'path', path1)
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.having((e) => e.osError?.errorCode, 'errorCode', stdlibc.ENOENT),
76+
),
77+
);
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});
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test('path1 is a broken symlink', () {
81+
final path1 = '$tmp/file1';
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final path2 = '$tmp/file2';
83+
Link(path1).createSync('$tmp/file3');
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File(path2).writeAsStringSync('Hello World');
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86+
expect(
87+
() => fileSystem.same(path1, path2),
88+
throwsA(
89+
isA<PathNotFoundException>()
90+
.having((e) => e.message, 'message', 'stat failed')
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.having((e) => e.path, 'path', path1)
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.having((e) => e.osError?.errorCode, 'errorCode', stdlibc.ENOENT),
93+
),
94+
);
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});
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97+
test('path2 is a broken symlink', () {
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final path1 = '$tmp/file1';
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final path2 = '$tmp/file2';
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File(path1).writeAsStringSync('Hello World');
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Link(path2).createSync('$tmp/file3');
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expect(
104+
() => fileSystem.same(path1, path2),
105+
throwsA(
106+
isA<PathNotFoundException>()
107+
.having((e) => e.message, 'message', 'stat failed')
108+
.having((e) => e.path, 'path', path2)
109+
.having((e) => e.osError?.errorCode, 'errorCode', stdlibc.ENOENT),
110+
),
111+
);
112+
});
113+
114+
test('path1 and path2 same, broken symlinks', () {
115+
final path1 = '$tmp/file1';
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final path2 = '$tmp/file1';
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Link(path1).createSync('$tmp/file3');
118+
119+
expect(
120+
() => fileSystem.same(path1, path2),
121+
throwsA(
122+
isA<PathNotFoundException>()
123+
.having((e) => e.message, 'message', 'stat failed')
124+
.having((e) => e.path, 'path', path1)
125+
.having((e) => e.osError?.errorCode, 'errorCode', stdlibc.ENOENT),
126+
),
127+
);
128+
});
129+
130+
test('different files, same content', () {
131+
final path1 = '$tmp/file1';
132+
final path2 = '$tmp/file2';
133+
File(path1).writeAsStringSync('Hello World');
134+
File(path2).writeAsStringSync('Hello World');
135+
136+
expect(fileSystem.same(path1, path2), isFalse);
137+
});
138+
139+
test('same file, absolute and relative paths', () {
140+
Directory.current = tmp;
141+
final path1 = '$tmp/file1';
142+
const path2 = 'file1';
143+
File(path1).writeAsStringSync('Hello World');
144+
145+
expect(fileSystem.same(path1, path2), isTrue);
146+
});
147+
148+
test('file path1, symlink path2', () {
149+
final path1 = '$tmp/file1';
150+
final path2 = '$tmp/file2';
151+
File(path1).writeAsStringSync('Hello World');
152+
Link(path2).createSync(path1);
153+
154+
expect(fileSystem.same(path1, path2), isTrue);
155+
});
156+
157+
test('file symlink path1, symlink path2', () {
158+
final path1 = '$tmp/file1';
159+
final path2 = '$tmp/file2';
160+
File('$tmp/file3').writeAsStringSync('Hello World');
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Link(path1).createSync('$tmp/file3');
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Link(path2).createSync('$tmp/file3');
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164+
expect(fileSystem.same(path1, path2), isTrue);
165+
});
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167+
test('files through intermediate symlinks', () {
168+
Directory('$tmp/subdir').createSync();
169+
Link('$tmp/link-to-subdir').createSync('$tmp/subdir');
170+
final path1 = '$tmp/subdir/file1';
171+
final path2 = '$tmp/link-to-subdir/file1';
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File(path1).writeAsStringSync('Hello World');
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174+
expect(fileSystem.same(path1, path2), isTrue);
175+
});
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177+
test('hard links to same file', () {
178+
final path1 = '$tmp/file1';
179+
final path2 = '$tmp/file2';
180+
File(path1).writeAsStringSync('Hello World');
181+
stdlibc.link(path1, path2);
182+
expect(fileSystem.same(path1, path2), isTrue);
183+
});
184+
185+
test('different directories, same content', () {
186+
final path1 = '$tmp/dir1';
187+
final path2 = '$tmp/dir2';
188+
Directory(path1).createSync();
189+
Directory(path2).createSync();
190+
191+
expect(fileSystem.same(path1, path2), isFalse);
192+
});
193+
194+
test('same directory, absolute and relative paths', () {
195+
Directory.current = tmp;
196+
final path1 = '$tmp/dir1';
197+
const path2 = 'dir1';
198+
Directory(path1).createSync();
199+
200+
expect(fileSystem.same(path1, path2), isTrue);
201+
});
202+
203+
test('directory path1, symlink path2', () {
204+
final path1 = '$tmp/dir1';
205+
final path2 = '$tmp/dir2';
206+
Directory(path1).createSync();
207+
Link(path2).createSync(path1);
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209+
expect(fileSystem.same(path1, path2), isTrue);
210+
});
211+
212+
test('directory symlink path1, symlink path2', () {
213+
final path1 = '$tmp/dir1';
214+
final path2 = '$tmp/dir2';
215+
Directory('$tmp/dir3').createSync();
216+
Link(path1).createSync('$tmp/dir3');
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Link(path2).createSync('$tmp/dir3');
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219+
expect(fileSystem.same(path1, path2), isTrue);
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});
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222+
test('directories through intermediate symlinks', () {
223+
Directory('$tmp/subdir').createSync();
224+
Link('$tmp/link-to-subdir').createSync('$tmp/subdir');
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final path1 = '$tmp/subdir/dir1';
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final path2 = '$tmp/link-to-subdir/dir1';
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Directory(path1).createSync();
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expect(fileSystem.same(path1, path2), isTrue);
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});
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});
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}

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