Firestore Swift Cpp Experiment

[cherylEnkidu]

Here are some imperfections in this PR. Please feel free to suggest better solutions:

1. Exposure of C++ APIs in the Objective-C Interface The Swift layer can only access public APIs of Objective-C. In Swift Package Manager, only a single path can be designated as the public header path. To enable additional features in the Swift layer, it must access internal C++ members held by the Objective-C object.

2. Swift's async/await functionality requires Objective-C callbacks for implementation. As a result, a public API—used exclusively by the Swift layer—was introduced. (Potentially this can be avoid using a C++ class contains Swift member, since the current structure only supports one way dependency, Swift class has C++ member. This impl is listed as a future improvement)

3. The FirebaseFirestoreCpp binary build structure in Swift Package Manager is currently written as pseudo-code and has not been verified.

4. The include path in this PR using relative path instead of full path, since full path leads to build failure for unknown reason.

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Apple API Diff Report

Commit: 0e81241c75ca2be6977aee732588d277d0ae9fe3 Last updated: Tue Feb 11 13:31 PST 2025 View workflow logs & download artifacts

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[BUILD ERROR] FirebaseFirestoreInternal

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FirebaseCore

Functions

[MODIFIED] FIRFirebaseVersion

[MODIFIED] FIRFirebaseVersion

Swift:
+  func FirebaseVersion () -> String
-  func FirebaseVersion () -> String
Objective-C:
+  NS_SWIFT_NAME ( FirebaseVersion ()) NSString * FIRFirebaseVersion ( void )
-  NSString * _Nonnull FIRFirebaseVersion ( void )

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[BUILD ERROR] FirebaseFirestore

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[cherylEnkidu]

I only see relative paths in public headers which is required. Is there a place where relative headers are used other than in a public header?

Aw I see, so public headers can only used relative path?

The reason I am asking is that I cannot include existing files from the previous API folder, Firestore/core/src/api. For example, I am unable to add Firestore/core/src/api/aggregate_query.h. Even when using a relative path for aggregate_query, the file contains other includes with full paths that Swift Package Manager cannot resolve.

Also, use relative path would fail syntax check: Firestore/core/interfaceForSwift/api/collection_stage.h:19: Include the directory when naming .h files [build/include_subdir]