Initial sync startup/3-way merge (#238)

- Initial implementation of InitialSyncOrchestrator, integrated with
  ReconciliationQueue to apply incoming sync query results
- Added a buffer queue for incoming remote events to ReconciliationQueue, so
  remote API sync can be turned off indpendently of applying mutations from
  sync queries
- Made CancelAwareBlockOperation a standalone class
- Model extensions
  - Change ModelSchema+Syncable to ModelSchema+Attributes
  - Added 'ModelSchema.isSystem' convenience getter
  - Change 'hasSyncableModels' to look for the existence of any non-system
    models; all models are considered syncable by default (no local model support
    at launch)
  - Added ModelGraphs to track Model connection dependencies for initial sync
- Made AtomicValue public so it can be used in plugins; added convenience
  methods for RangeReplaceableCollection
- Removed isSyncable schema attribute in favor of designating all non-system
  models as syncable; added buffer queue for incoming subscription event
  submission to reconciliation queue; refactoring & renaming
- Added 'DataStore.internalOperation' to contain errors about nil weak
  references being unavailable
- Added convenience DataStoreError constructor for missing reconciliation queue
- Use code-generated models in AmplifyTestCommon
- Fix some linting warnings
- Minor test cleanup
- Added responders to MockAPICategoryPlugin to let us invoke callback of methods
- Added unit tests for InitialSyncOperation happy path
- Convert ModelRegistry.register to take protocol argument rather than concrete type

Author: palpatim

Amplify.xcodeproj/project.pbxproj

@@ -25,7 +25,7 @@ extension DataStoreResult {
     }
 
     public static var emptyResult: DataStoreResult<Void> {
-        .success(())
+        .successfulVoid
     }
 
 }

Amplify/Categories/DataStore/DataStoreCallback.swift

@@ -14,6 +14,7 @@ public enum DataStoreError: Error {
     case configuration(ErrorDescription, RecoverySuggestion, Error? = nil)
     case conflict(DataStoreSyncConflict)
     case decodingError(ErrorDescription, RecoverySuggestion)
+    case internalOperation(ErrorDescription, RecoverySuggestion, Error? = nil)
     case invalidDatabase(path: String, Error? = nil)
     case invalidModelName(String)
     case invalidOperation(causedBy: Error? = nil)
@@ -45,6 +46,7 @@ extension DataStoreError: AmplifyError {
             """
         case .configuration(let errorDescription, _, _),
              .decodingError(let errorDescription, _),
+             .internalOperation(let errorDescription, _, _),
              .sync(let errorDescription, _, _),
              .unknown(let errorDescription, _, _):
             return errorDescription
@@ -71,6 +73,7 @@ extension DataStoreError: AmplifyError {
             """
         case .configuration(_, let recoverySuggestion, _),
              .decodingError(_, let recoverySuggestion),
+             .internalOperation(_, let recoverySuggestion, _),
              .sync(_, let recoverySuggestion, _),
              .unknown(_, let recoverySuggestion, _):
             return recoverySuggestion
@@ -82,6 +85,7 @@ extension DataStoreError: AmplifyError {
         case .api(let amplifyError):
             return amplifyError
         case .configuration(_, _, let underlyingError),
+             .internalOperation(_, _, let underlyingError),
              .invalidDatabase(_, let underlyingError),
              .invalidOperation(let underlyingError),
              .sync(_, _, let underlyingError),

Amplify/Categories/DataStore/DataStoreError.swift

@@ -8,7 +8,7 @@
 public extension ModelRegistry {
     static var hasSyncableModels: Bool {
         if #available(iOS 13.0, *) {
-            return models.contains { $0.schema.isSyncable }
+            return models.contains { !$0.schema.isSystem }
         } else {
             return false
         }

Amplify/Categories/DataStore/Model/ModelRegistry+Syncable.swift

@@ -24,7 +24,7 @@ public struct ModelRegistry {
         }
     }
 
-    public static func register<M: Model>(modelType: M.Type) {
+    public static func register(modelType: Model.Type) {
         concurrencyQueue.sync {
             let modelDecoder: ModelDecoder = { jsonString, jsonDecoder in
                 let model = try modelType.from(json: jsonString, decoder: jsonDecoder)

Amplify/Categories/DataStore/Model/ModelRegistry.swift

@@ -5,8 +5,15 @@
 // SPDX-License-Identifier: Apache-2.0
 //
 
+/// Convenience getters for attributes
 public extension ModelSchema {
+
     var isSyncable: Bool {
-        attributes.contains(.isSyncable)
+        !attributes.contains(.isSystem)
+    }
+
+    var isSystem: Bool {
+        attributes.contains(.isSystem)
     }
+
 }

Amplify/Categories/DataStore/Model/ModelSchema+Syncable.swift renamed to Amplify/Categories/DataStore/Model/ModelSchema+Attributes.swift

@@ -21,9 +21,6 @@ public enum ModelAttribute {
     /// TODO: What does this mean?
     case index
 
-    /// Instances of this model are syncable to the remote API via the API category
-    case isSyncable
-
     /// This model is used by the Amplify system or a plugin, and should not be used by the app developer
     case isSystem
 }

Amplify/Categories/DataStore/Model/ModelSchema.swift

@@ -11,6 +11,7 @@ import Foundation
 ///
 /// The associated value represents the iso language code.
 
+// swiftlint:disable file_length
 // swiftlint:disable type_body_length
 public enum LanguageType: String {
     case afar = "aa"
@@ -181,6 +182,7 @@ public enum LanguageType: String {
     case friulian = "fur"
     case westernFrisian = "fy"
     case irish = "ga"
+    // swiftlint:disable:next identifier_name
     case ga = "gaa"
     case gagauz = "gag"
     case ganChinese = "gan"

Amplify/Categories/Predictions/Models/LanguageType.swift

@@ -7,7 +7,8 @@
 
 import Foundation
 
-public protocol StorageDownloadDataOperation: AmplifyOperation<StorageDownloadDataRequest, Progress, Data, StorageError> {}
+public protocol StorageDownloadDataOperation: AmplifyOperation<StorageDownloadDataRequest,
+Progress, Data, StorageError> {}
 
 public extension HubPayload.EventName.Storage {
     /// eventName for HubPayloads emitted by this operation

Amplify/Categories/Storage/Operation/StorageDownloadDataOperation.swift

@@ -7,7 +7,8 @@
 
 import Foundation
 
-public protocol StorageUploadDataOperation: AmplifyOperation<StorageUploadDataRequest, Progress, String, StorageError> {}
+public protocol StorageUploadDataOperation: AmplifyOperation<StorageUploadDataRequest,
+Progress, String, StorageError> {}
 
 public extension HubPayload.EventName.Storage {
     /// eventName for HubPayloads emitted by this operation