[path_provider] Move Windows FFI behind a conditional import (#3056)
Moves the real implementation of path_provider_windows behind a
conditional export, instead exporting a stub on platforms that don't
support dart:ffi. This avoids build breakage in web projects that have
transitive dependencies on path_provider (and thus path_provider_windows
due to manual endorsement).
This will no longer be necessary once
https://github.com/flutter/flutter/issues/52267 is fixed, since only
Windows builds will ever need to have code-level dependency on
path_provider_windows.
diff --git a/packages/path_provider/path_provider_windows/CHANGELOG.md b/packages/path_provider/path_provider_windows/CHANGELOG.md
index 0b73286..a7cfe1d 100644
--- a/packages/path_provider/path_provider_windows/CHANGELOG.md
+++ b/packages/path_provider/path_provider_windows/CHANGELOG.md
@@ -1,3 +1,9 @@
+## 0.0.4
+
+* Move the actual implementation behind a conditional import, exporting
+ a stub for platforms that don't support FFI. Fixes web builds in
+ projects with transitive dependencies on path_provider.
+
## 0.0.3
* Add missing `pluginClass: none` for compatibilty with stable channel.
diff --git a/packages/path_provider/path_provider_windows/lib/path_provider_windows.dart b/packages/path_provider/path_provider_windows/lib/path_provider_windows.dart
index e29b70a..ed96698 100644
--- a/packages/path_provider/path_provider_windows/lib/path_provider_windows.dart
+++ b/packages/path_provider/path_provider_windows/lib/path_provider_windows.dart
@@ -2,221 +2,8 @@
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
-import 'dart:async';
-import 'dart:io';
-import 'dart:ffi';
-
-import 'package:ffi/ffi.dart';
-import 'package:meta/meta.dart';
-import 'package:path/path.dart' as path;
-import 'package:path_provider_platform_interface/path_provider_platform_interface.dart';
-import 'package:path_provider_windows/folders.dart';
-import 'package:win32/win32.dart';
-
-/// Wraps the Win32 VerQueryValue API call.
-///
-/// This class exists to allow injecting alternate metadata in tests without
-/// building multiple custom test binaries.
-@visibleForTesting
-class VersionInfoQuerier {
- /// Returns the value for [key] in [versionInfo]s English strings section, or
- /// null if there is no such entry, or if versionInfo is null.
- getStringValue(Pointer<Uint8> versionInfo, key) {
- if (versionInfo == null) {
- return null;
- }
- const kEnUsLanguageCode = '040904e4';
- final keyPath = TEXT('\\StringFileInfo\\$kEnUsLanguageCode\\$key');
- final length = allocate<Uint32>();
- final valueAddress = allocate<IntPtr>();
- try {
- if (VerQueryValue(versionInfo, keyPath, valueAddress, length) == 0) {
- return null;
- }
- return Pointer<Utf16>.fromAddress(valueAddress.value)
- .unpackString(length.value);
- } finally {
- free(keyPath);
- free(length);
- free(valueAddress);
- }
- }
-}
-
-/// The Windows implementation of [PathProviderPlatform]
-///
-/// This class implements the `package:path_provider` functionality for Windows.
-class PathProviderWindows extends PathProviderPlatform {
- /// The object to use for performing VerQueryValue calls.
- @visibleForTesting
- VersionInfoQuerier versionInfoQuerier = VersionInfoQuerier();
-
- /// This is typically the same as the TMP environment variable.
- @override
- Future<String> getTemporaryPath() async {
- final buffer = allocate<Uint16>(count: MAX_PATH + 1).cast<Utf16>();
- String path;
-
- try {
- final length = GetTempPath(MAX_PATH, buffer);
-
- if (length == 0) {
- final error = GetLastError();
- throw WindowsException(error);
- } else {
- path = buffer.unpackString(length);
-
- // GetTempPath adds a trailing backslash, but SHGetKnownFolderPath does
- // not. Strip off trailing backslash for consistency with other methods
- // here.
- if (path.endsWith('\\')) {
- path = path.substring(0, path.length - 1);
- }
- }
-
- // Ensure that the directory exists, since GetTempPath doesn't.
- final directory = Directory(path);
- if (!directory.existsSync()) {
- await directory.create(recursive: true);
- }
-
- return Future.value(path);
- } finally {
- free(buffer);
- }
- }
-
- @override
- Future<String> getApplicationSupportPath() async {
- final appDataRoot = await getPath(WindowsKnownFolder.RoamingAppData);
- final directory = Directory(
- path.join(appDataRoot, _getApplicationSpecificSubdirectory()));
- // Ensure that the directory exists if possible, since it will on other
- // platforms. If the name is longer than MAXPATH, creating will fail, so
- // skip that step; it's up to the client to decide what to do with the path
- // in that case (e.g., using a short path).
- if (directory.path.length <= MAX_PATH) {
- if (!directory.existsSync()) {
- await directory.create(recursive: true);
- }
- }
- return directory.path;
- }
-
- @override
- Future<String> getApplicationDocumentsPath() =>
- getPath(WindowsKnownFolder.Documents);
-
- @override
- Future<String> getDownloadsPath() => getPath(WindowsKnownFolder.Downloads);
-
- /// Retrieve any known folder from Windows.
- ///
- /// folderID is a GUID that represents a specific known folder ID, drawn from
- /// [WindowsKnownFolder].
- Future<String> getPath(String folderID) {
- final pathPtrPtr = allocate<IntPtr>();
- Pointer<Utf16> pathPtr;
-
- try {
- GUID knownFolderID = GUID.fromString(folderID);
-
- final hr = SHGetKnownFolderPath(
- knownFolderID.addressOf, KF_FLAG_DEFAULT, NULL, pathPtrPtr);
-
- if (FAILED(hr)) {
- if (hr == E_INVALIDARG || hr == E_FAIL) {
- throw WindowsException(hr);
- }
- }
-
- pathPtr = Pointer<Utf16>.fromAddress(pathPtrPtr.value);
- final path = pathPtr.unpackString(MAX_PATH);
- return Future.value(path);
- } finally {
- CoTaskMemFree(pathPtr.cast());
- free(pathPtrPtr);
- }
- }
-
- /// Returns the relative path string to append to the root directory returned
- /// by Win32 APIs for application storage (such as RoamingAppDir) to get a
- /// directory that is unique to the application.
- ///
- /// The convention is to use company-name\product-name\. This will use that if
- /// possible, using the data in the VERSIONINFO resource, with the following
- /// fallbacks:
- /// - If the company name isn't there, that component will be dropped.
- /// - If the product name isn't there, it will use the exe's filename (without
- /// extension).
- String _getApplicationSpecificSubdirectory() {
- String companyName;
- String productName;
-
- final Pointer<Utf16> moduleNameBuffer =
- allocate<Uint16>(count: MAX_PATH + 1).cast<Utf16>();
- final Pointer<Uint32> unused = allocate<Uint32>();
- Pointer<Uint8> infoBuffer;
- try {
- // Get the module name.
- final moduleNameLength = GetModuleFileName(0, moduleNameBuffer, MAX_PATH);
- if (moduleNameLength == 0) {
- final error = GetLastError();
- throw WindowsException(error);
- }
-
- // From that, load the VERSIONINFO resource
- int infoSize = GetFileVersionInfoSize(moduleNameBuffer, unused);
- if (infoSize != 0) {
- infoBuffer = allocate<Uint8>(count: infoSize);
- if (GetFileVersionInfo(moduleNameBuffer, 0, infoSize, infoBuffer) ==
- 0) {
- free(infoBuffer);
- infoBuffer = null;
- }
- }
- companyName = _sanitizedDirectoryName(
- versionInfoQuerier.getStringValue(infoBuffer, 'CompanyName'));
- productName = _sanitizedDirectoryName(
- versionInfoQuerier.getStringValue(infoBuffer, 'ProductName'));
-
- // If there was no product name, use the executable name.
- if (productName == null) {
- productName = path.basenameWithoutExtension(
- moduleNameBuffer.unpackString(moduleNameLength));
- }
-
- return companyName != null
- ? path.join(companyName, productName)
- : productName;
- } finally {
- free(moduleNameBuffer);
- free(unused);
- if (infoBuffer != null) {
- free(infoBuffer);
- }
- }
- }
-
- /// Makes [rawString] safe as a directory component. See
- /// https://docs.microsoft.com/en-us/windows/win32/fileio/naming-a-file#naming-conventions
- ///
- /// If after sanitizing the string is empty, returns null.
- String _sanitizedDirectoryName(String rawString) {
- if (rawString == null) {
- return null;
- }
- String sanitized = rawString
- // Replace banned characters.
- .replaceAll(RegExp(r'[<>:"/\\|?*]'), '_')
- // Remove trailing whitespace.
- .trimRight()
- // Ensure that it does not end with a '.'.
- .replaceAll(RegExp(r'[.]+$'), '');
- const kMaxComponentLength = 255;
- if (sanitized.length > kMaxComponentLength) {
- sanitized = sanitized.substring(0, kMaxComponentLength);
- }
- return sanitized.isEmpty ? null : sanitized;
- }
-}
+// path_provider_windows is implemented using FFI; export a stub for platforms
+// that don't support FFI (e.g., web) to avoid having transitive dependencies
+// break web compilation.
+export 'src/path_provider_windows_stub.dart'
+ if (dart.library.ffi) 'src/path_provider_windows_real.dart';
diff --git a/packages/path_provider/path_provider_windows/lib/folders.dart b/packages/path_provider/path_provider_windows/lib/src/folders.dart
similarity index 100%
rename from packages/path_provider/path_provider_windows/lib/folders.dart
rename to packages/path_provider/path_provider_windows/lib/src/folders.dart
diff --git a/packages/path_provider/path_provider_windows/lib/src/path_provider_windows_real.dart b/packages/path_provider/path_provider_windows/lib/src/path_provider_windows_real.dart
new file mode 100644
index 0000000..7ff448a
--- /dev/null
+++ b/packages/path_provider/path_provider_windows/lib/src/path_provider_windows_real.dart
@@ -0,0 +1,223 @@
+// Copyright 2020 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'dart:async';
+import 'dart:io';
+import 'dart:ffi';
+
+import 'package:ffi/ffi.dart';
+import 'package:meta/meta.dart';
+import 'package:path/path.dart' as path;
+import 'package:path_provider_platform_interface/path_provider_platform_interface.dart';
+import 'package:win32/win32.dart';
+
+import 'folders.dart';
+
+/// Wraps the Win32 VerQueryValue API call.
+///
+/// This class exists to allow injecting alternate metadata in tests without
+/// building multiple custom test binaries.
+@visibleForTesting
+class VersionInfoQuerier {
+ /// Returns the value for [key] in [versionInfo]s English strings section, or
+ /// null if there is no such entry, or if versionInfo is null.
+ getStringValue(Pointer<Uint8> versionInfo, key) {
+ if (versionInfo == null) {
+ return null;
+ }
+ const kEnUsLanguageCode = '040904e4';
+ final keyPath = TEXT('\\StringFileInfo\\$kEnUsLanguageCode\\$key');
+ final length = allocate<Uint32>();
+ final valueAddress = allocate<IntPtr>();
+ try {
+ if (VerQueryValue(versionInfo, keyPath, valueAddress, length) == 0) {
+ return null;
+ }
+ return Pointer<Utf16>.fromAddress(valueAddress.value)
+ .unpackString(length.value);
+ } finally {
+ free(keyPath);
+ free(length);
+ free(valueAddress);
+ }
+ }
+}
+
+/// The Windows implementation of [PathProviderPlatform]
+///
+/// This class implements the `package:path_provider` functionality for Windows.
+class PathProviderWindows extends PathProviderPlatform {
+ /// The object to use for performing VerQueryValue calls.
+ @visibleForTesting
+ VersionInfoQuerier versionInfoQuerier = VersionInfoQuerier();
+
+ /// This is typically the same as the TMP environment variable.
+ @override
+ Future<String> getTemporaryPath() async {
+ final buffer = allocate<Uint16>(count: MAX_PATH + 1).cast<Utf16>();
+ String path;
+
+ try {
+ final length = GetTempPath(MAX_PATH, buffer);
+
+ if (length == 0) {
+ final error = GetLastError();
+ throw WindowsException(error);
+ } else {
+ path = buffer.unpackString(length);
+
+ // GetTempPath adds a trailing backslash, but SHGetKnownFolderPath does
+ // not. Strip off trailing backslash for consistency with other methods
+ // here.
+ if (path.endsWith('\\')) {
+ path = path.substring(0, path.length - 1);
+ }
+ }
+
+ // Ensure that the directory exists, since GetTempPath doesn't.
+ final directory = Directory(path);
+ if (!directory.existsSync()) {
+ await directory.create(recursive: true);
+ }
+
+ return Future.value(path);
+ } finally {
+ free(buffer);
+ }
+ }
+
+ @override
+ Future<String> getApplicationSupportPath() async {
+ final appDataRoot = await getPath(WindowsKnownFolder.RoamingAppData);
+ final directory = Directory(
+ path.join(appDataRoot, _getApplicationSpecificSubdirectory()));
+ // Ensure that the directory exists if possible, since it will on other
+ // platforms. If the name is longer than MAXPATH, creating will fail, so
+ // skip that step; it's up to the client to decide what to do with the path
+ // in that case (e.g., using a short path).
+ if (directory.path.length <= MAX_PATH) {
+ if (!directory.existsSync()) {
+ await directory.create(recursive: true);
+ }
+ }
+ return directory.path;
+ }
+
+ @override
+ Future<String> getApplicationDocumentsPath() =>
+ getPath(WindowsKnownFolder.Documents);
+
+ @override
+ Future<String> getDownloadsPath() => getPath(WindowsKnownFolder.Downloads);
+
+ /// Retrieve any known folder from Windows.
+ ///
+ /// folderID is a GUID that represents a specific known folder ID, drawn from
+ /// [WindowsKnownFolder].
+ Future<String> getPath(String folderID) {
+ final pathPtrPtr = allocate<IntPtr>();
+ Pointer<Utf16> pathPtr;
+
+ try {
+ GUID knownFolderID = GUID.fromString(folderID);
+
+ final hr = SHGetKnownFolderPath(
+ knownFolderID.addressOf, KF_FLAG_DEFAULT, NULL, pathPtrPtr);
+
+ if (FAILED(hr)) {
+ if (hr == E_INVALIDARG || hr == E_FAIL) {
+ throw WindowsException(hr);
+ }
+ }
+
+ pathPtr = Pointer<Utf16>.fromAddress(pathPtrPtr.value);
+ final path = pathPtr.unpackString(MAX_PATH);
+ return Future.value(path);
+ } finally {
+ CoTaskMemFree(pathPtr.cast());
+ free(pathPtrPtr);
+ }
+ }
+
+ /// Returns the relative path string to append to the root directory returned
+ /// by Win32 APIs for application storage (such as RoamingAppDir) to get a
+ /// directory that is unique to the application.
+ ///
+ /// The convention is to use company-name\product-name\. This will use that if
+ /// possible, using the data in the VERSIONINFO resource, with the following
+ /// fallbacks:
+ /// - If the company name isn't there, that component will be dropped.
+ /// - If the product name isn't there, it will use the exe's filename (without
+ /// extension).
+ String _getApplicationSpecificSubdirectory() {
+ String companyName;
+ String productName;
+
+ final Pointer<Utf16> moduleNameBuffer =
+ allocate<Uint16>(count: MAX_PATH + 1).cast<Utf16>();
+ final Pointer<Uint32> unused = allocate<Uint32>();
+ Pointer<Uint8> infoBuffer;
+ try {
+ // Get the module name.
+ final moduleNameLength = GetModuleFileName(0, moduleNameBuffer, MAX_PATH);
+ if (moduleNameLength == 0) {
+ final error = GetLastError();
+ throw WindowsException(error);
+ }
+
+ // From that, load the VERSIONINFO resource
+ int infoSize = GetFileVersionInfoSize(moduleNameBuffer, unused);
+ if (infoSize != 0) {
+ infoBuffer = allocate<Uint8>(count: infoSize);
+ if (GetFileVersionInfo(moduleNameBuffer, 0, infoSize, infoBuffer) ==
+ 0) {
+ free(infoBuffer);
+ infoBuffer = null;
+ }
+ }
+ companyName = _sanitizedDirectoryName(
+ versionInfoQuerier.getStringValue(infoBuffer, 'CompanyName'));
+ productName = _sanitizedDirectoryName(
+ versionInfoQuerier.getStringValue(infoBuffer, 'ProductName'));
+
+ // If there was no product name, use the executable name.
+ if (productName == null) {
+ productName = path.basenameWithoutExtension(
+ moduleNameBuffer.unpackString(moduleNameLength));
+ }
+
+ return companyName != null
+ ? path.join(companyName, productName)
+ : productName;
+ } finally {
+ free(moduleNameBuffer);
+ free(unused);
+ if (infoBuffer != null) {
+ free(infoBuffer);
+ }
+ }
+ }
+
+ /// Makes [rawString] safe as a directory component. See
+ /// https://docs.microsoft.com/en-us/windows/win32/fileio/naming-a-file#naming-conventions
+ ///
+ /// If after sanitizing the string is empty, returns null.
+ String _sanitizedDirectoryName(String rawString) {
+ if (rawString == null) {
+ return null;
+ }
+ String sanitized = rawString
+ // Replace banned characters.
+ .replaceAll(RegExp(r'[<>:"/\\|?*]'), '_')
+ // Remove trailing whitespace.
+ .trimRight()
+ // Ensure that it does not end with a '.'.
+ .replaceAll(RegExp(r'[.]+$'), '');
+ const kMaxComponentLength = 255;
+ if (sanitized.length > kMaxComponentLength) {
+ sanitized = sanitized.substring(0, kMaxComponentLength);
+ }
+ return sanitized.isEmpty ? null : sanitized;
+ }
+}
diff --git a/packages/path_provider/path_provider_windows/lib/src/path_provider_windows_stub.dart b/packages/path_provider/path_provider_windows/lib/src/path_provider_windows_stub.dart
new file mode 100644
index 0000000..fedb537
--- /dev/null
+++ b/packages/path_provider/path_provider_windows/lib/src/path_provider_windows_stub.dart
@@ -0,0 +1,27 @@
+// Copyright 2020 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'package:path_provider_platform_interface/path_provider_platform_interface.dart';
+
+/// A stub implementation to satisfy compilation of multi-platform packages that
+/// depend on path_provider_windows. This should never actually be created.
+///
+/// Notably, because path_provider needs to manually register
+/// path_provider_windows, anything with a transitive dependency on
+/// path_provider will also depend on path_provider_windows, not just at the
+/// pubspec level but the code level.
+class PathProviderWindows extends PathProviderPlatform {
+ /// Errors on attempted instantiation of the stub. It exists only to satisfy
+ /// compile-time dependencies, and should never actually be created.
+ PathProviderWindows() {
+ assert(false);
+ }
+
+ /// Stub; see comment on VersionInfoQuerier.
+ VersionInfoQuerier versionInfoQuerier;
+}
+
+/// Stub to satisfy the analyzer, which doesn't seem to handle conditional
+/// exports correctly.
+class VersionInfoQuerier {}
diff --git a/packages/path_provider/path_provider_windows/pubspec.yaml b/packages/path_provider/path_provider_windows/pubspec.yaml
index 998f4e2..38f6316 100644
--- a/packages/path_provider/path_provider_windows/pubspec.yaml
+++ b/packages/path_provider/path_provider_windows/pubspec.yaml
@@ -1,7 +1,7 @@
name: path_provider_windows
description: Windows implementation of the path_provider plugin
homepage: https://github.com/flutter/plugins/tree/master/packages/path_provider/path_provider_windows
-version: 0.0.3
+version: 0.0.4
flutter:
plugin:
