hook for custom VFS in SourceKit #24708

marcrasi · 2019-05-11T01:09:35Z

(working on upstreaming this in #24417; this PR is to get it into tensorflow so that we can start using it internally)

Defines a FileSystemProvider interface that can be used to implement custom filesystems.

Defines a SourceKit::addFileSystemProvider method, which is to be called after sourcekitd_initialize(), that registers new providers in the global context.

Modifies editoropen, cursorinfo, and codecomplete requests to accept new optional key.vfs.name and key.vfs.args parameters. If key.vfs.name is defined, then SourceKit asks the FileSystemProvider registered under that name to provide a filesystem. (The FileSystemProvider receives the string array key.vfs.args, so that the requester can pass context to the custom filesystem.) SourceKit then uses the returned filesystem throughout the request.

Includes tests for all the requests.

burmako

Great work on a very important practical problem! This was clearly a result of a thoughtful investigation, careful design and thorough execution. I am super happy that we didn't need to resort to hacks to support this functionality.

lib/ClangImporter/ClangImporter.cpp

tools/SourceKit/include/SourceKit/Core/Context.h

tools/SourceKit/include/SourceKit/Core/LangSupport.h

tools/SourceKit/include/SourceKit/Core/Context.h

tools/SourceKit/tools/sourcekitd-test/sourcekitd-test.cpp

tools/SourceKit/tools/sourcekitd/include/sourcekitd/FileSystemProvider.h

tools/SourceKit/tools/sourcekitd/lib/API/Requests.cpp

marcrasi · 2019-05-14T18:54:07Z

I'm going to do a small refactoring that will address a few of your comments about function signatures:

I will remove all the default arguments (though I will make overloads for CompilerInstance::setup, SwiftASTManager::getInvocation, and SwiftASTManager::initCompilerInvocation that allow existing callers to work unchanged, because each of those has a huge number of existing callers that would be better to deal with incrementally as we add VFS to more types of requests.)
I will require the FileSystem parameter to always be non-nullptr, and assert that it's non-nullptr.
I will put the FileSystem parameter second-to-last whenever there is an output Error parameter, or a callback parameter, because it seems to be the convention that those parameters should always be last.

marcrasi · 2019-05-14T22:09:57Z