Firestore Swift Cpp Experiment

FirebaseCombineSwift.podspec

@@ -59,6 +59,7 @@ for internal testing only. It should not be published.
 
   s.pod_target_xcconfig = {
     'HEADER_SEARCH_PATHS' => '"${PODS_TARGET_SRCROOT}"',
+    'SWIFT_OBJC_INTEROP_MODE' => 'objcxx',
   }
 
   s.test_spec 'unit' do |unit_tests|
@@ -81,7 +82,8 @@ for internal testing only. It should not be published.
     unit_tests.exclude_files = 'FirebaseCombineSwift/Tests/Unit/**/*Template.swift'
     unit_tests.requires_app_host = true
     unit_tests.pod_target_xcconfig = {
-      'SWIFT_OBJC_BRIDGING_HEADER' => '$(PODS_TARGET_SRCROOT)/FirebaseCombineSwift/Tests/Unit/FirebaseCombine-unit-Bridging-Header.h'
+      'SWIFT_OBJC_BRIDGING_HEADER' => '$(PODS_TARGET_SRCROOT)/FirebaseCombineSwift/Tests/Unit/FirebaseCombine-unit-Bridging-Header.h',
+      'SWIFT_OBJC_INTEROP_MODE' => 'objcxx',
     }
     unit_tests.dependency 'OCMock'
     unit_tests.dependency 'FirebaseAuthTestingSupport'

FirebaseCore/Sources/Public/FirebaseCore/FIRVersion.h

@@ -19,7 +19,16 @@
 NS_ASSUME_NONNULL_BEGIN
 
 /** Returns the current version of Firebase. */
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 NS_SWIFT_NAME(FirebaseVersion())
 NSString* FIRFirebaseVersion(void);
 
+#ifdef __cplusplus
+}
+#endif
+
 NS_ASSUME_NONNULL_END

FirebaseFirestore.podspec

@@ -31,6 +31,12 @@ Google Cloud Firestore is a NoSQL document database built for automatic scaling,
     'FirebaseFirestoreInternal/**/*.[mh]',
     'Firestore/Swift/Source/**/*.swift',
   ]
+
+  s.pod_target_xcconfig = {
+    # Enables C++ <-> Swift interop (by default it's only C)
+    "SWIFT_OBJC_INTEROP_MODE" => "objcxx",
+  }
+
   s.resource_bundles = {
     "#{s.module_name}_Privacy" => 'Firestore/Swift/Source/Resources/PrivacyInfo.xcprivacy'
   }

FirebaseFirestoreInternal.podspec

@@ -28,7 +28,10 @@ Google Cloud Firestore is a NoSQL document database built for automatic scaling,
   # Header files that constitute the interface to this module. Only Objective-C
   # headers belong here, since FirebaseFirestore is primarily an Objective-C
   # framework.
-  s.public_header_files = 'Firestore/Source/Public/FirebaseFirestore/*.h'
+  s.public_header_files = [
+    'Firestore/Source/Public/FirebaseFirestore/*.h',
+    'Firestore/core/swift/include/*.h'
+  ]
 
   # source_files contains most of the header and source files for the project.
   # This includes files named in `public_header_files`.
@@ -52,6 +55,7 @@ Google Cloud Firestore is a NoSQL document database built for automatic scaling,
     'Firestore/core/include/**/*.{cc,mm}',
     'Firestore/core/src/**/*.{cc,mm}',
     'FirebaseAuth/Interop/**/*.h',
+    'Firestore/core/swift/**/*.{cc,h}',
   ]
 
   # Internal headers that aren't necessarily globally unique. Most C++ internal

Firestore/Source/API/FIRFirestore+Internal.h

@@ -79,8 +79,6 @@ NS_ASSUME_NONNULL_BEGIN
 
 - (const std::shared_ptr<firebase::firestore::util::AsyncQueue> &)workerQueue;
 
-@property(nonatomic, assign, readonly) std::shared_ptr<api::Firestore> wrapped;
-
 @property(nonatomic, assign, readonly) const model::DatabaseId &databaseID;
 @property(nonatomic, strong, readonly) FSTUserDataReader *dataReader;
 

Firestore/Source/API/FIRInterface.mm

@@ -0,0 +1,36 @@
+/*
+ * Copyright 2024 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#import <Foundation/Foundation.h>
+
+#import "Firestore/Source/Public/FirebaseFirestore/FIRInterface.h"
+
+#import "Firestore/core/src/api/used_by_objective_c.h"
+#include "Firestore/core/src/util/string_apple.h"
+
+using firebase::firestore::util::MakeString;
+
+NS_ASSUME_NONNULL_BEGIN
+
+@implementation FIRInterface
+
++ (void)print:(NSString *)content {
+  CppInterfaceCalledByObjectiveC::print(MakeString(content));
+}
+
+@end
+
+NS_ASSUME_NONNULL_END

Firestore/Source/Public/FirebaseFirestore/FIRFirestore.h

@@ -15,6 +15,7 @@
  */
 
 #import <Foundation/Foundation.h>
+#import <memory>
 
 #import "FIRListenerRegistration.h"
 
@@ -30,6 +31,16 @@
 @class FIRWriteBatch;
 @class FIRPersistentCacheIndexManager;
 
+namespace firebase {
+namespace firestore {
+namespace api {
+class Firestore;
+}  // namespace api
+}  // namespace firestore
+}  // namespace firebase
+
+namespace api = firebase::firestore::api;
+
 NS_ASSUME_NONNULL_BEGIN
 
 /**
@@ -91,6 +102,8 @@
  */
 + (instancetype)firestoreForDatabase:(NSString *)database NS_SWIFT_NAME(firestore(database:));
 
+@property(nonatomic, assign, readonly) std::shared_ptr<api::Firestore> wrapped;
+
 /**
  * Custom settings used to configure this `Firestore` object.
  */

Firestore/Source/Public/FirebaseFirestore/FIRInterface.h

@@ -0,0 +1,29 @@
+/*
+ * Copyright 2024 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#import <Foundation/Foundation.h>
+
+NS_ASSUME_NONNULL_BEGIN
+
+@interface FIRInterface : NSObject
+
+#pragma mark - Create Filter
+
++ (void)print:(NSString *)content;
+
+@end
+
+NS_ASSUME_NONNULL_END

Firestore/Swift/Source/AsyncAwait/Firestore+AsyncAwait.swift

@@ -115,4 +115,8 @@
       }
     }
   }
+
+  func pipeline() -> PipelineSource {
+    return PipelineSource(firebase.firestore.api.FirestorePipeline.pipeline(wrapped))
+  }
 }

Firestore/Swift/Source/SwiftAPI/PipelineSource.swift

@@ -0,0 +1,14 @@
+//
+//  PipelineSource.swift
+//  Pods
+//
+//  Created by Cheryl Lin on 2024-12-12.
+//
+
+public class PipelineSource {
+  let cppPtr: firebase.firestore.api.PipelineSource
+
+  public init(_ cppSource: firebase.firestore.api.PipelineSource) {
+    cppPtr = cppSource
+  }
+}

Firestore/Swift/Source/SwiftAPI/SwiftCppAPI.swift

@@ -0,0 +1,25 @@
+/*
+ * Copyright 2024 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#if SWIFT_PACKAGE
+  @_exported import FirebaseFirestoreCpp
+#endif // SWIFT_PACKAGE
+
+public class SwiftCallingCpp {
+  public init(_ value: String) {
+    CppInterfaceCalledBySwift.print(std.string(value))
+  }
+}

Firestore/core/CMakeLists.txt

@@ -218,6 +218,8 @@ firebase_ios_glob(
   src/objc/*.h
   src/remote/*.cc
   src/remote/*.h
+  swift/include/*.h
+  swift/src/*.cc
   EXCLUDE ${nanopb_sources}
 )
 

Firestore/core/src/api/firestore.cc

@@ -227,6 +227,10 @@ void Firestore::SetClientLanguage(std::string language_token) {
   GrpcConnection::SetClientLanguage(std::move(language_token));
 }
 
+PipelineSource Firestore::pipeline() {
+  return {shared_from_this()};
+}
+
 std::unique_ptr<ListenerRegistration> Firestore::AddSnapshotsInSyncListener(
     std::unique_ptr<core::EventListener<Empty>> listener) {
   EnsureClientConfigured();

Firestore/core/src/api/firestore.h

@@ -29,6 +29,7 @@
 #include "Firestore/core/src/model/database_id.h"
 #include "Firestore/core/src/util/byte_stream.h"
 #include "Firestore/core/src/util/status_fwd.h"
+#include "Firestore/core/swift/include/pipeline_source.h"
 
 namespace firebase {
 namespace firestore {
@@ -125,6 +126,8 @@ class Firestore : public std::enable_shared_from_this<Firestore> {
    */
   static void SetClientLanguage(std::string language_token);
 
+  PipelineSource pipeline();
+
  private:
   void EnsureClientConfigured();
   core::DatabaseInfo MakeDatabaseInfo() const;

Firestore/core/src/api/used_by_objective_c.cc

@@ -0,0 +1,22 @@
+/*
+ * Copyright 2024 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "used_by_objective_c.h"
+#include <iostream>
+
+void CppInterfaceCalledByObjectiveC::print(std::string content) {
+  std::cout << "C++ function runs with value: " << content << std::endl;
+}

Firestore/core/src/api/used_by_objective_c.h

@@ -0,0 +1,27 @@
+/*
+ * Copyright 2024 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef FIREBASE_USED_BY_SWIFT_H
+#define FIREBASE_USED_BY_SWIFT_H
+
+#include <string>
+
+class CppInterfaceCalledByObjectiveC {
+ public:
+  static void print(std::string content);
+};
+
+#endif  // FIREBASE_USED_BY_SWIFT_H

Firestore/core/swift/include/FirebaseFirestoreCpp.h

@@ -0,0 +1,27 @@
+/*
+ * Copyright 2024 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef FIREBASE_FIREBASEFIRESTORECPP_H
+#define FIREBASE_FIREBASEFIRESTORECPP_H
+
+#import "collection_stage.h"
+#import "firestore_pipeline.h"
+#import "pipeline.h"
+#import "pipeline_source.h"
+#import "stage.h"
+#import "used_by_swift.h"
+
+#endif  // FIREBASE_FIREBASEFIRESTORECPP_H

Firestore/core/swift/include/collection_stage.h

@@ -0,0 +1,29 @@
+//
+// Created by Cheryl Lin on 2024-12-11.
+//
+
+#ifndef FIREBASE_COLLECTION_GROUP_STAGE_H
+#define FIREBASE_COLLECTION_GROUP_STAGE_H
+
+#include <string>
+#include "stage.h"
+
+namespace firebase {
+namespace firestore {
+
+namespace api {
+
+class Collection : public Stage {
+ public:
+  Collection(std::string collection_path);
+
+ private:
+  std::string collection_path_;
+};
+
+}  // namespace api
+
+}  // namespace firestore
+}  // namespace firebase
+
+#endif  // FIREBASE_COLLECTION_GROUP_STAGE_H

Firestore/core/swift/include/firestore_pipeline.h

@@ -0,0 +1,25 @@
+//
+// Created by Cheryl Lin on 2024-12-10.
+//
+
+#ifndef FIREBASE_FIRESTORE_PIPELINE_H
+#define FIREBASE_FIRESTORE_PIPELINE_H
+
+#include "pipeline_source.h"
+
+namespace firebase {
+namespace firestore {
+
+namespace api {
+class Firestore;
+
+class FirestorePipeline {
+ public:
+  static PipelineSource pipeline(std::shared_ptr<Firestore> firestore);
+};
+
+}  // namespace api
+}  // namespace firestore
+}  // namespace firebase
+
+#endif  // FIREBASE_FIRESTORE_PIPELINE_H