[native_assets] Spaces in paths

[dcharkes]

I can confirm this works in all but one use case, and that's when there is a space in the path of the resolved executable. In that case, the spaces appear as %20 in the LoadLibraryW call which Windows is not happy about. This can happen, for example, when the resolved executable lives in Program Files.

The following example demonstrates this behavior (using native_add_app again):

$ dart --enable-experiment=native-assets build --output="native output" .\bin\native_add_app.dart
$ New-Item -Path .\native_add_app.exe -ItemType SymbolicLink -Value ".\native output\native_add_app.exe"
$ .\native_add_app.exe
Invoking a native function to calculate 1 + 2.
Unhandled exception:
Invalid argument(s): Couldn't resolve native function 'add' in 'package:native_add_library/native_add_library.dart' : Failed to load dynamic library 'lib\native_add_library.dll': Failed to load dynamic library 'c:/workspace/native/pkgs/native_assets_cli/example/build/native_add_app/native%20output/lib/native_add_library.dll': The specified module could not be found.
 (error code: 126).

#0      Native._ffi_resolver.#ffiClosure0 (dart:ffi-patch/ffi_patch.dart)
#1      Native._ffi_resolver_function (dart:ffi-patch/ffi_patch.dart:1523)
#2      add (package:native_add_library/native_add_library.dart)
#3      main (file:///c:/workspace/native/pkgs/native_assets_cli/example/build/native_add_app/bin/native_add_app.dart:9)
#4      _delayEntrypointInvocation.<anonymous closure> (dart:isolate-patch/isolate_patch.dart:297)
#5      _RawReceivePort._handleMessage (dart:isolate-patch/isolate_patch.dart:184)

This is running against the current main:

Dart SDK version: 3.5.0-edge.09e87e6d7bd18e3b08cc96c3a42b8e3f37a096d6 (main) (Wed Jun 19 14:50:30 2024 +0000) on "windows_x64"

Originally posted by @dnys1 in #55207 (comment)

[lrhn]

If there is a %20 then it's most likely because the path text was parsed as a URI, and not unparsed back to a system path.
The path using forward slashes together with a Windows drive name suggests the same thing.

Use File.fromUri(uri).path rather than uri.path. The latter can contain escaped characters, the former should be a valid file path, which may need to be quoted since it can contain spaces.
(If the path contained a %, or any URI delimiter character, that would probably be escaped too.)

[dcharkes]

If there is a %20 then it's most likely because the path text was parsed as a URI, and not unparsed back to a system path. The path using forward slashes together with a Windows drive name suggests the same thing.

Correct.

Use File.fromUri(uri).path rather than uri.path. The latter can contain escaped characters, the former should be a valid file path, which may need to be quoted since it can contain spaces. (If the path contained a %, or any URI delimiter character, that would probably be escaped too.)

The error was in the C++ code, but the same logic applies. 👍

Fix: https://dart-review.googlesource.com/c/sdk/+/372421