Adds xdg_directories package to access Linux well known directories.

packages/xdg_directories/.gitignore

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+# Miscellaneous
+*.class
+*.log
+*.pyc
+*.swp
+.DS_Store
+.atom/
+.buildlog/
+.history
+.svn/
+
+# IntelliJ related
+*.iml
+*.ipr
+*.iws
+.idea/
+
+# The .vscode folder contains launch configuration and tasks you configure in
+# VS Code which you may wish to be included in version control, so this line
+# is commented out by default.
+#.vscode/
+
+# Flutter/Dart/Pub related
+**/doc/api/
+.dart_tool/
+.flutter-plugins
+.flutter-plugins-dependencies
+.packages
+.pub-cache/
+.pub/
+build/
+
+# Android related
+**/android/**/gradle-wrapper.jar
+**/android/.gradle
+**/android/captures/
+**/android/gradlew
+**/android/gradlew.bat
+**/android/local.properties
+**/android/**/GeneratedPluginRegistrant.java
+
+# iOS/XCode related
+**/ios/**/*.mode1v3
+**/ios/**/*.mode2v3
+**/ios/**/*.moved-aside
+**/ios/**/*.pbxuser
+**/ios/**/*.perspectivev3
+**/ios/**/*sync/
+**/ios/**/.sconsign.dblite
+**/ios/**/.tags*
+**/ios/**/.vagrant/
+**/ios/**/DerivedData/
+**/ios/**/Icon?
+**/ios/**/Pods/
+**/ios/**/.symlinks/
+**/ios/**/profile
+**/ios/**/xcuserdata
+**/ios/.generated/
+**/ios/Flutter/App.framework
+**/ios/Flutter/Flutter.framework
+**/ios/Flutter/Flutter.podspec
+**/ios/Flutter/Generated.xcconfig
+**/ios/Flutter/app.flx
+**/ios/Flutter/app.zip
+**/ios/Flutter/flutter_assets/
+**/ios/Flutter/flutter_export_environment.sh
+**/ios/ServiceDefinitions.json
+**/ios/Runner/GeneratedPluginRegistrant.*
+
+# Exceptions to above rules.
+!**/ios/**/default.mode1v3
+!**/ios/**/default.mode2v3
+!**/ios/**/default.pbxuser
+!**/ios/**/default.perspectivev3
+!/packages/flutter_tools/test/data/dart_dependencies_test/**/.packages

packages/xdg_directories/.metadata

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+# This file tracks properties of this Flutter project.
+# Used by Flutter tool to assess capabilities and perform upgrades etc.
+#
+# This file should be version controlled and should not be manually edited.
+
+version:
+  revision: d8c0deb1b6c116be79ceeca005f893be34ab5df2
+  channel: master
+
+project_type: package

packages/xdg_directories/CHANGELOG.md

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+## [0.1.0] - Initial Release
+
+* Initial release includes all the features described in the README.md

packages/xdg_directories/LICENSE

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+Copyright 2020 The Flutter Authors. All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are
+met:
+
+    * Redistributions of source code must retain the above copyright
+      notice, this list of conditions and the following disclaimer.
+    * Redistributions in binary form must reproduce the above
+      copyright notice, this list of conditions and the following
+      disclaimer in the documentation and/or other materials provided
+      with the distribution.
+    * Neither the name of Google Inc. nor the names of its
+      contributors may be used to endorse or promote products derived
+      from this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

packages/xdg_directories/README.md

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+# `xdg_directories`
+
+A Dart package for reading XDG directory configuration information on Linux.
+
+## Getting Started
+
+On Linux, `xdg` is a system developed by [freedesktop.org](freedesktop.org), a
+project to work on interoperability and shared base technology for free software
+desktop environments for Linux.
+
+This Dart package can be used to determine the directory configuration
+information defined by `xdg`, such as where the Documents or Desktop directories
+are. These are called "user directories" and are defined in configuration file
+in the user's home directory.
+
+See [this wiki](https://wiki.archlinux.org/index.php/XDG_Base_Directory) for
+more details of the XDG Base Directory implementation.
+
+To use this package, the basic XDG values for the following are available via a Dart API:
+
+ - `dataHome` - The single base directory relative to which user-specific data
+   files should be written. (Corresponds to `$XDG_DATA_HOME`).
+
+ - `configHome` - The a single base directory relative to which user-specific
+   configuration files should be written. (Corresponds to `$XDG_CONFIG_HOME`).
+
+ - `dataDirs` - The list of preference-ordered base directories relative to
+   which data files should be searched. (Corresponds to `$XDG_DATA_DIRS`).
+
+ - `configDirs` - The list of preference-ordered base directories relative to
+   which configuration files should be searched. (Corresponds to
+   `$XDG_CONFIG_DIRS`).
+
+ - `cacheHome` - The base directory relative to which user-specific
+   non-essential (cached) data should be written. (Corresponds to
+   `$XDG_CACHE_HOME`).
+
+ - `runtimeDir` - The base directory relative to which user-specific runtime
+   files and other file objects should be placed. (Corresponds to
+   `$XDG_RUNTIME_DIR`).
+
+ - `getUserDirectoryNames()` - Returns a set of the names of user directories
+   defined in the `xdg` configuration files.
+
+ - `getUserDirectory(String dirName)` - Gets the value of the user dir with the
+   given name. Requesting a user dir that doesn't exist returns `null`. The
+   `dirName` argument is case-insensitive. See [this
+   wiki](https://wiki.archlinux.org/index.php/XDG_user_directories) for more
+   details and what values of `dirName` might be available.
+

packages/xdg_directories/lib/xdg_directories.dart

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+// Copyright 2020 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+library xdg_directories;
+
+import 'dart:convert';
+import 'dart:io';
+
+import 'package:flutter/cupertino.dart';
+import 'package:path/path.dart' as path;
+import 'package:process/process.dart';
+
+/// An override function used by the tests to override the environment variable
+/// lookups using [xdgEnvironmentOverride].
+typedef EnvironmentOverride = String Function(String envVar);
+
+/// A testing setter that replaces the real environment lookups with an override.
+///
+/// Set to null to stop overriding.
+///
+/// Only available to tests.
+@visibleForTesting
+set xdgEnvironmentOverride(EnvironmentOverride override) {
+  _xdgEnvironmentOverride = override;
+  _getenv = _xdgEnvironmentOverride ?? _productionGetEnv;
+}
+
+/// A testing getter that returns the current value of the override that
+/// replaces the real environment lookups with an override.
+///
+/// Only available to tests.
+EnvironmentOverride get xdgEnvironmentOverride => _xdgEnvironmentOverride;
+EnvironmentOverride _xdgEnvironmentOverride;
+EnvironmentOverride _productionGetEnv = (String value) => Platform.environment[value];
+EnvironmentOverride _getenv = _productionGetEnv;
+
+/// A testing function that replaces the process manager used to run xdg-user-path
+/// with the one supplied.
+///
+/// Only available to tests.
+@visibleForTesting
+set xdgProcessManager(ProcessManager processManager) {
+  _processManager = processManager;
+}
+
+ProcessManager _processManager = const LocalProcessManager();
+
+List<Directory> _directoryListFromEnvironment(String envVar, String fallback) {
+  assert(envVar != null);
+  assert(fallback != null);
+  String value = _getenv(envVar);
+  if (value == null || value.isEmpty) {
+    value = fallback;
+  }
+  return value.split(':').where((String value) {
+    return value.isNotEmpty;
+  }).map<Directory>((String entry) {
+    return Directory(entry);
+  }).toList();
+}
+
+Directory _directoryFromEnvironment(String envVar, String fallback) {
+  assert(envVar != null);
+  final String value = _getenv(envVar);
+  if (value == null || value.isEmpty) {
+    if (fallback == null) {
+      return null;
+    }
+    return _getDefaultDir(fallback);
+  }
+  return Directory(value);
+}
+
+Directory _getDefaultDir(String suffix) {
+  assert(suffix != null);
+  assert(suffix.isNotEmpty);
+  final String homeDir = _getenv('HOME');
+  if (homeDir == null || homeDir.isEmpty) {
+    throw StateError('The "HOME" environment variable is not set. This package (and POSIX) '
+        'requires that HOME be set.');
+  }
+  return Directory(path.joinAll(<String>[homeDir, suffix]));
+}
+
+/// The base directory relative to which user-specific
+/// non-essential (cached) data should be written. (Corresponds to
+/// `$XDG_CACHE_HOME`).
+///
+/// Throws [StateError] if the HOME environment variable is not set.
+Directory get cacheHome => _directoryFromEnvironment('XDG_CACHE_HOME', '.cache');
+
+/// The list of preference-ordered base directories relative to
+/// which configuration files should be searched. (Corresponds to
+/// `$XDG_CONFIG_DIRS`).
+///
+/// Throws [StateError] if the HOME environment variable is not set.
+List<Directory> get configDirs => _directoryListFromEnvironment('XDG_CONFIG_DIRS', '/etc/xdg');
+
+/// The a single base directory relative to which user-specific
+/// configuration files should be written. (Corresponds to `$XDG_CONFIG_HOME`).
+///
+/// Throws [StateError] if the HOME environment variable is not set.
+Directory get configHome => _directoryFromEnvironment('XDG_CONFIG_HOME', '.config');
+
+/// The list of preference-ordered base directories relative to
+/// which data files should be searched. (Corresponds to `$XDG_DATA_DIRS`).
+///
+/// Throws [StateError] if the HOME environment variable is not set.
+List<Directory> get dataDirs => _directoryListFromEnvironment('XDG_DATA_DIRS', '/usr/local/share:/usr/share');
+
+/// The base directory relative to which user-specific data files should be
+/// written. (Corresponds to `$XDG_DATA_HOME`).
+///
+/// Throws [StateError] if the HOME environment variable is not set.
+Directory get dataHome => _directoryFromEnvironment('XDG_DATA_HOME', '.local/share');
+
+/// The base directory relative to which user-specific runtime
+/// files and other file objects should be placed. (Corresponds to
+/// `$XDG_RUNTIME_DIR`).
+///
+/// Throws [StateError] if the HOME environment variable is not set.
+Directory get runtimeDir => _directoryFromEnvironment('XDG_RUNTIME_DIR', null);
+
+/// Gets the xdg user directory named by `dirName`.
+///
+/// Use [getUserDirectoryNames] to find out the list of available names.
+Directory getUserDirectory(String dirName) {
+  final ProcessResult result = _processManager.runSync(
+    <String>['xdg-user-dir', dirName],
+    includeParentEnvironment: true,
+    stdoutEncoding: Encoding.getByName('utf8'),
+  );
+  final String path = utf8.decode(result.stdout).split('\n')[0];
+  return Directory(path);
+}
+
+/// Gets the set of user directory names that xdg knows about.
+///
+/// These are not paths, they are names of xdg values.  Call [getUserDirectory]
+/// to get the associated directory.
+///
+/// These are the names of the variables in "[configHome]/user-dirs.dirs", with
+/// the `XDG_` prefix removed and the `_DIR` suffix removed.
+Set<String> getUserDirectoryNames() {
+  final File configFile = File(path.join(configHome.path, 'user-dirs.dirs'));
+  List<String> contents;
+  try {
+    contents = configFile.readAsLinesSync();
+  } on FileSystemException catch (e) {
+    return const <String>{};
+  }
+  final Set<String> result = <String>{};
+  final RegExp dirRegExp = RegExp(r'^\s*XDG_(?<dirname>.*)_DIR\s*=\s*(?<dir>.*)\s*$');
+  for (String line in contents) {
+    final RegExpMatch match = dirRegExp.firstMatch(line);
+    if (match == null) {
+      continue;
+    }
+    result.add(match.namedGroup('dirname'));
+  }
+  return result;
+}

packages/xdg_directories/pubspec.yaml

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+name: xdg_directories
+description: A Dart package for reading XDG directory configuration information on Linux.
+version: 1.0.0
+homepage: https://github.com/flutter/packages/tree/master/packages/animations
+
+environment:
+  sdk: ">=2.3.0 <3.0.0"
+
+dependencies:
+  path: ">=1.6.4"
+  process: ">=3.0.12"
+  flutter:
+    sdk: flutter
+
+dev_dependencies:
+  mockito: ">=4.1.1"
+  flutter_test:
+    sdk: flutter