[Sessions] Add SessionStartEvent wrapper for building the nanopb proto (#10311)

Author: samedson

FirebaseSessions.podspec

@@ -35,16 +35,22 @@ Pod::Spec.new do |s|
 
   base_dir = "FirebaseSessions/"
   s.source_files = [
-    base_dir + 'Sources/**/*.swift',
+    base_dir + 'Sources/**/*.{swift,h,m}',
+    base_dir + 'Protogen/**/*.{c,h,m,mm}',
   ]
 
   s.dependency 'FirebaseCore', '~> 10.0'
   s.dependency 'FirebaseCoreExtension', '~> 10.0'
   s.dependency 'FirebaseInstallations', '~> 10.0'
+  s.dependency 'GoogleDataTransport', '~> 9.2'
+  s.dependency 'nanopb', '>= 2.30908.0', '< 2.30910.0'
 
   s.pod_target_xcconfig = {
     'GCC_C_LANGUAGE_STANDARD' => 'c99',
-    'HEADER_SEARCH_PATHS' => '"${PODS_TARGET_SRCROOT}"'
+    'HEADER_SEARCH_PATHS' => '"${PODS_TARGET_SRCROOT}"',
+    'GCC_PREPROCESSOR_DEFINITIONS' =>
+      # For nanopb:
+      'PB_FIELD_32BIT=1 PB_NO_PACKED_STRUCTS=1 PB_ENABLE_MALLOC=1',
   }
 
   s.test_spec 'unit' do |unit_tests|

FirebaseSessions/Sources/EventGDTLogger.swift

@@ -0,0 +1,49 @@
+//
+// Copyright 2022 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
+
+@_implementationOnly import GoogleDataTransport
+
+protocol EventGDTLoggerProtocol {
+  func logEvent(event: SessionStartEvent, completion: @escaping (Result<Void, Error>) -> Void)
+}
+
+///
+/// EventGDTLogger is responsible for
+///   1) Creating GDT Events and logging them to the GoogleDataTransport SDK
+///   2) Handling debugging situations (eg. running in Simulator or printing the event to console)
+///
+class EventGDTLogger: EventGDTLoggerProtocol {
+  let googleDataTransport: GoogleDataTransportProtocol
+
+  init(googleDataTransport: GoogleDataTransportProtocol) {
+    self.googleDataTransport = googleDataTransport
+  }
+
+  /// Logs the event to FireLog, taking into account debugging cases such as running
+  /// in simulator.
+  func logEvent(event: SessionStartEvent, completion: @escaping (Result<Void, Error>) -> Void) {
+    let gdtEvent = googleDataTransport.eventForTransport()
+    gdtEvent.dataObject = event
+    gdtEvent.qosTier = GDTCOREventQoS.qosDefault
+    #if targetEnvironment(simulator)
+      Logger.logDebug("Logging events using fast QOS due to running on a simulator")
+      gdtEvent.qosTier = GDTCOREventQoS.qoSFast
+    #endif // targetEnvironment(simulator)
+
+    googleDataTransport.logGDTEvent(event: gdtEvent, completion: completion)
+  }
+}

FirebaseSessions/Sources/FirebaseSessions.swift

@@ -14,11 +14,15 @@
 
 import Foundation
 
-import FirebaseCore
-import FirebaseInstallations
-
 // Avoids exposing internal FirebaseCore APIs to Swift users.
 @_implementationOnly import FirebaseCoreExtension
+@_implementationOnly import FirebaseInstallations
+@_implementationOnly import GoogleDataTransport
+
+private enum GoogleDataTransportConfig {
+  static let sessionsLogSource = "1974"
+  static let sessionsTarget = GDTCORTarget.FLL
+}
 
 @objc(FIRSessionsProvider)
 protocol SessionsProvider {
@@ -38,9 +42,18 @@ protocol SessionsProvider {
 
   // MARK: - Initializers
 
+  // Initializes the SDK and top-level classes
   required convenience init(appID: String, installations: InstallationsProtocol) {
+    let googleDataTransport = GDTCORTransport(
+      mappingID: GoogleDataTransportConfig.sessionsLogSource,
+      transformers: nil,
+      target: GoogleDataTransportConfig.sessionsTarget
+    )
+
+    let fireLogger = EventGDTLogger(googleDataTransport: googleDataTransport!)
+
     let identifiers = Identifiers(installations: installations)
-    let coordinator = SessionCoordinator(identifiers: identifiers)
+    let coordinator = SessionCoordinator(identifiers: identifiers, fireLogger: fireLogger)
     let initiator = SessionInitiator()
 
     self.init(appID: appID,
@@ -49,6 +62,7 @@ protocol SessionsProvider {
               initiator: initiator)
   }
 
+  // Initializes the SDK and begines the process of listening for lifecycle events and logging events
   init(appID: String, identifiers: Identifiers, coordinator: SessionCoordinator,
        initiator: SessionInitiator) {
     self.appID = appID
@@ -61,7 +75,11 @@ protocol SessionsProvider {
 
     self.initiator.beginListening {
       self.identifiers.generateNewSessionID()
-      self.coordinator.runMain()
+      let event = SessionStartEvent(identifiers: self.identifiers)
+      DispatchQueue.global().async {
+        self.coordinator.attemptLoggingSessionStart(event: event) { result in
+        }
+      }
     }
   }
 

FirebaseSessions/Sources/GoogleDataTransport+GoogleDataTransportProtocol.swift

@@ -0,0 +1,41 @@
+//
+// Copyright 2022 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
+
+@_implementationOnly import GoogleDataTransport
+
+enum GoogleDataTransportProtocolErrors: Error {
+  case writeFailure
+}
+
+protocol GoogleDataTransportProtocol {
+  func logGDTEvent(event: GDTCOREvent, completion: @escaping (Result<Void, Error>) -> Void)
+  func eventForTransport() -> GDTCOREvent
+}
+
+extension GDTCORTransport: GoogleDataTransportProtocol {
+  func logGDTEvent(event: GDTCOREvent, completion: @escaping (Result<Void, Error>) -> Void) {
+    sendDataEvent(event) { wasWritten, error in
+      if let error = error {
+        completion(.failure(error))
+      } else if !wasWritten {
+        completion(.failure(GoogleDataTransportProtocolErrors.writeFailure))
+      } else {
+        completion(.success(()))
+      }
+    }
+  }
+}

FirebaseSessions/Sources/Identifiers.swift

@@ -14,7 +14,8 @@
 // limitations under the License.
 
 import Foundation
-import FirebaseInstallations
+
+@_implementationOnly import FirebaseInstallations
 
 let sessionIDUserDefaultsKey = "com.firebase.sessions.sessionID"
 let lastSessionIDUserDefaultsKey = "com.firebase.sessions.lastSessionID"
@@ -28,7 +29,7 @@ protocol IdentifierProvider {
     get
   }
 
-  var lastSessionID: String {
+  var previousSessionID: String {
     get
   }
 }
@@ -43,24 +44,26 @@ protocol IdentifierProvider {
 class Identifiers: IdentifierProvider {
   private let installations: InstallationsProtocol
 
-  private var uuid: UUID
+  private var _sessionID: UUID
 
   init(installations: InstallationsProtocol) {
     self.installations = installations
-    uuid = UUID()
+    _sessionID = UUID()
   }
 
+  // Generates a new Session ID. If there was already a generated Session ID
+  // from the last session during the app's lifecycle, it will also set the last Session ID
   func generateNewSessionID() {
-    uuid = UUID()
+    _sessionID = UUID()
 
     let lastStoredSessionID = UserDefaults.standard.string(forKey: sessionIDUserDefaultsKey) ?? ""
     UserDefaults.standard.set(lastStoredSessionID, forKey: lastSessionIDUserDefaultsKey)
 
-    let newSessionID = uuid.uuidString.replacingOccurrences(of: "-", with: "").lowercased()
+    let newSessionID = _sessionID.uuidString.replacingOccurrences(of: "-", with: "").lowercased()
     UserDefaults.standard.set(newSessionID, forKey: sessionIDUserDefaultsKey)
   }
 
-  // This method must be run on a background thread due to how Firebase Installations
+  // Fetches the Installation ID from Firebase Installation Service. This method must be run on a background thread due to how Firebase Installations
   // handles threading.
   var installationID: String {
     if Thread.isMainThread {
@@ -103,7 +106,7 @@ class Identifiers: IdentifierProvider {
     return UserDefaults.standard.string(forKey: sessionIDUserDefaultsKey) ?? ""
   }
 
-  var lastSessionID: String {
+  var previousSessionID: String {
     return UserDefaults.standard.string(forKey: lastSessionIDUserDefaultsKey) ?? ""
   }
 }

FirebaseSessions/Sources/Installations+InstallationsProtocol.swift

@@ -14,7 +14,8 @@
 // limitations under the License.
 
 import Foundation
-import FirebaseInstallations
+
+@_implementationOnly import FirebaseInstallations
 
 protocol InstallationsProtocol {
   func installationID(completion: @escaping (Result<String, Error>) -> Void)

FirebaseSessions/Sources/Logger.swift

@@ -17,6 +17,9 @@ import Foundation
 
 @_implementationOnly import FirebaseCoreExtension
 
+///
+/// Logger is responsible for printing console logs
+///
 enum Logger {
   private static let logServiceTag = "[FirebaseSessions]"
   private static let logCode = "I-SES000000"

FirebaseSessions/Sources/NanoPB/FIRSESNanoPBHelpers.h

@@ -0,0 +1,62 @@
+//
+// Copyright 2022 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 FIRSESNanoPBHelpers_h
+#define FIRSESNanoPBHelpers_h
+
+#import <nanopb/pb.h>
+#import <nanopb/pb_decode.h>
+#import <nanopb/pb_encode.h>
+
+NS_ASSUME_NONNULL_BEGIN
+
+// It seems impossible to specify the nullability of the `fields` parameter below,
+// yet the compiler complains that it's missing a nullability specifier. Google
+// yields no results at this time.
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wnullability-completeness"
+NSData* _Nullable FIRSESEncodeProto(const pb_field_t fields[],
+                                    const void* _Nonnull proto,
+                                    NSError** error);
+#pragma clang diagnostic pop
+
+/// Mallocs a pb_bytes_array and copies the given NSData bytes into the bytes array.
+/// @note Memory needs to be freed manually, through pb_free or pb_release.
+/// @param data The data to copy into the new bytes array.
+pb_bytes_array_t* _Nullable FIRSESEncodeData(NSData* _Nullable data);
+
+/// Mallocs a pb_bytes_array and copies the given NSString's bytes into the bytes array.
+/// @note Memory needs to be freed manually, through pb_free or pb_release.
+/// @param string The string to encode as pb_bytes.
+pb_bytes_array_t* _Nullable FIRSESEncodeString(NSString* _Nullable string);
+
+/// Checks if 2 nanopb arrays are equal
+/// @param array array to check
+/// @param expected expected value of the array
+BOOL FIRSESIsPBArrayEqual(pb_bytes_array_t* _Nullable array, pb_bytes_array_t* _Nullable expected);
+
+/// Checks if a nanopb string is equal to an NSString
+/// @param pbString nanopb string to check
+/// @param str NSString that's expected
+BOOL FIRSESIsPBStringEqual(pb_bytes_array_t* _Nullable pbString, NSString* _Nullable str);
+
+/// Checks if a nanopb array is equal to NSData
+/// @param pbArray nanopb array to check
+/// @param data NSData that's expected
+BOOL FIRSESIsPBDataEqual(pb_bytes_array_t* _Nullable pbArray, NSData* _Nullable data);
+
+NS_ASSUME_NONNULL_END
+
+#endif /* FIRSESNanoPBHelpers_h */