Merge pull request #709 from apollographql/rm/public-promise

Remove Public Promise

Author: designatednerd

Apollo.xcodeproj/project.pbxproj

@@ -14,6 +14,7 @@
 		9B95EDC022CAA0B000702BB2 /* GETTransformerTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 9B95EDBF22CAA0AF00702BB2 /* GETTransformerTests.swift */; };
 		9BA1244A22D8A8EA00BF1D24 /* JSONSerialziation+Sorting.swift in Sources */ = {isa = PBXBuildFile; fileRef = 9BA1244922D8A8EA00BF1D24 /* JSONSerialziation+Sorting.swift */; };
 		9BA1245E22DE116B00BF1D24 /* Result+Helpers.swift in Sources */ = {isa = PBXBuildFile; fileRef = 9BA1245D22DE116B00BF1D24 /* Result+Helpers.swift */; };
+		9BA3130E2302BEA5007B7FC5 /* DispatchQueue+Optional.swift in Sources */ = {isa = PBXBuildFile; fileRef = 9BA3130D2302BEA5007B7FC5 /* DispatchQueue+Optional.swift */; };
 		9BDE43D122C6655300FD7C7F /* Cancellable.swift in Sources */ = {isa = PBXBuildFile; fileRef = 9BDE43D022C6655200FD7C7F /* Cancellable.swift */; };
 		9BDE43DD22C6705300FD7C7F /* GraphQLHTTPResponseError.swift in Sources */ = {isa = PBXBuildFile; fileRef = 9BDE43DC22C6705300FD7C7F /* GraphQLHTTPResponseError.swift */; };
 		9BDE43DF22C6708600FD7C7F /* GraphQLHTTPRequestError.swift in Sources */ = {isa = PBXBuildFile; fileRef = 9BDE43DE22C6708600FD7C7F /* GraphQLHTTPRequestError.swift */; };
@@ -270,6 +271,7 @@
 		9B95EDBF22CAA0AF00702BB2 /* GETTransformerTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = GETTransformerTests.swift; sourceTree = "<group>"; };
 		9BA1244922D8A8EA00BF1D24 /* JSONSerialziation+Sorting.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "JSONSerialziation+Sorting.swift"; sourceTree = "<group>"; };
 		9BA1245D22DE116B00BF1D24 /* Result+Helpers.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "Result+Helpers.swift"; sourceTree = "<group>"; };
+		9BA3130D2302BEA5007B7FC5 /* DispatchQueue+Optional.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "DispatchQueue+Optional.swift"; sourceTree = "<group>"; };
 		9BDE43D022C6655200FD7C7F /* Cancellable.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Cancellable.swift; sourceTree = "<group>"; };
 		9BDE43DC22C6705300FD7C7F /* GraphQLHTTPResponseError.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = GraphQLHTTPResponseError.swift; sourceTree = "<group>"; };
 		9BDE43DE22C6708600FD7C7F /* GraphQLHTTPRequestError.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = GraphQLHTTPRequestError.swift; sourceTree = "<group>"; };
@@ -711,6 +713,7 @@
 			children = (
 				9F578D8F1D8D2CB300C0EA36 /* Utilities.swift */,
 				9FCDFD221E33A0D8007519DC /* AsynchronousOperation.swift */,
+				9BA3130D2302BEA5007B7FC5 /* DispatchQueue+Optional.swift */,
 				9FE941CF1E62C771007CDD89 /* Promise.swift */,
 				9BA1245D22DE116B00BF1D24 /* Result+Helpers.swift */,
 				9F19D8431EED568200C57247 /* ResultOrPromise.swift */,
@@ -1230,6 +1233,7 @@
 				9FE941D01E62C771007CDD89 /* Promise.swift in Sources */,
 				9BA1245E22DE116B00BF1D24 /* Result+Helpers.swift in Sources */,
 				9FC750631D2A59F600458D91 /* ApolloClient.swift in Sources */,
+				9BA3130E2302BEA5007B7FC5 /* DispatchQueue+Optional.swift in Sources */,
 				9F86B6901E65533D00B885FF /* GraphQLResponseGenerator.swift in Sources */,
 				9FC9A9C21E2D3CAF0023C4D5 /* GraphQLInputValue.swift in Sources */,
 			);

Sources/Apollo/ApolloClient.swift

@@ -118,8 +118,8 @@ extension ApolloClient: ApolloClientProtocol {
     }
   }
 
-  public func clearCache() -> Promise<Void> {
-    return self.store.clearCache()
+  public func clearCache(callbackQueue: DispatchQueue = .main, completion: ((Result<Void, Error>) -> Void)? = nil) {
+    self.store.clearCache(completion: completion)
   }
 
   @discardableResult public func fetch<Query: GraphQLQuery>(query: Query,

Sources/Apollo/ApolloClientProtocol.swift

@@ -12,8 +12,10 @@ public protocol ApolloClientProtocol: class {
   /// Clears the underlying cache.
   /// Be aware: In more complex setups, the same underlying cache can be used across multiple instances, so if you call this on one instance, it'll clear that cache across all instances which share that cache.
   ///
-  /// - Returns: Promise which fulfills when clear is complete.
-  func clearCache() -> Promise<Void>
+  /// - Parameters:
+  ///   - callbackQueue: The queue to fall back on. Should default to the main queue.
+  ///   - completion: [optional] A completion closure to execute when clearing has completed. Should default to nil.
+  func clearCache(callbackQueue: DispatchQueue, completion: ((Result<Void, Error>) -> Void)?)
 
   /// Fetches a query from the server or from the local cache, depending on the current contents of the cache and the specified cache policy.
   ///

Sources/Apollo/ApolloStore.swift

@@ -50,14 +50,14 @@ public final class ApolloStore {
   /// Clears the instance of the cache. Note that a cache can be shared across multiple `ApolloClient` objects, so clearing that underlying cache will clear it for all clients.
   ///
   /// - Returns: A promise which fulfills when the Cache is cleared.
-  public func clearCache() -> Promise<Void> {
-    return Promise<Void> { fulfill, reject in
-      queue.async(flags: .barrier) {
-        self.cacheLock.withWriteLock {
-          self.cache.clear()
+  public func clearCache(callbackQueue: DispatchQueue = .main, completion: ((Result<Void, Error>) -> Void)? = nil) {
+    queue.async(flags: .barrier) {
+      self.cacheLock.withWriteLock {
+          self.cache.clearPromise()
         }.andThen {
-          fulfill(())
-        }
+          DispatchQueue.apollo_returnResultAsyncIfNeeded(on: callbackQueue,
+                                                         action: completion,
+                                                         result: .success(()))
       }
     }
   }
@@ -66,7 +66,7 @@ public final class ApolloStore {
     return Promise<Void> { fulfill, reject in
       queue.async(flags: .barrier) {
         self.cacheLock.withWriteLock {
-          self.cache.merge(records: records)
+          self.cache.mergePromise(records: records)
         }.andThen { changedKeys in
           self.didChangeKeys(changedKeys, context: context)
           fulfill(())
@@ -87,7 +87,7 @@ public final class ApolloStore {
     }
   }
 
-  public func withinReadTransaction<T>(_ body: @escaping (ReadTransaction) throws -> Promise<T>) -> Promise<T> {
+  func withinReadTransactionPromise<T>(_ body: @escaping (ReadTransaction) throws -> Promise<T>) -> Promise<T> {
     return Promise<ReadTransaction> { fulfill, reject in
       self.queue.async {
         self.cacheLock.lockForReading()
@@ -99,14 +99,32 @@ public final class ApolloStore {
       self.cacheLock.unlock()
     }
   }
-
-  public func withinReadTransaction<T>(_ body: @escaping (ReadTransaction) throws -> T) -> Promise<T> {
-    return withinReadTransaction {
-      Promise(fulfilled: try body($0))
+  
+  /// Performs an operation within a read transaction
+  ///
+  /// - Parameters:
+  ///   - body: The body of the operation to perform.
+  ///   - callbackQueue: [optional] The callback queue to use to perform the completion block on. Will perform on the current queue if not provided. Defaults to nil.
+  ///   - completion: [optional] The completion block to perform when the read transaction completes. Defaults to nil.
+  public func withinReadTransaction<T>(_ body: @escaping (ReadTransaction) throws -> T,
+                                       callbackQueue: DispatchQueue? = nil,
+                                       completion: ((Result<T, Error>) -> Void)? = nil) {
+    _ = self.withinReadTransactionPromise {
+        Promise(fulfilled: try body($0))
+      }
+      .andThen { object in
+        DispatchQueue.apollo_returnResultAsyncIfNeeded(on: callbackQueue,
+                                                       action: completion,
+                                                       result: .success(object))
+      }
+      .catch { error in
+        DispatchQueue.apollo_returnResultAsyncIfNeeded(on: callbackQueue,
+                                                       action: completion,
+                                                       result: .failure(error))
     }
   }
 
-  public func withinReadWriteTransaction<T>(_ body: @escaping (ReadWriteTransaction) throws -> Promise<T>) -> Promise<T> {
+  func withinReadWriteTransactionPromise<T>(_ body: @escaping (ReadWriteTransaction) throws -> Promise<T>) -> Promise<T> {
     return Promise<ReadWriteTransaction> { fulfill, reject in
       self.queue.async(flags: .barrier) {
         self.cacheLock.lockForWriting()
@@ -117,15 +135,33 @@ public final class ApolloStore {
       self.cacheLock.unlock()
     }
   }
-
-  public func withinReadWriteTransaction<T>(_ body: @escaping (ReadWriteTransaction) throws -> T) -> Promise<T> {
-    return withinReadWriteTransaction {
-      Promise(fulfilled: try body($0))
-    }
+  
+  /// Performs an operation within a read-write transaction
+  ///
+  /// - Parameters:
+  ///   - body: The body of the operation to perform
+  ///   - callbackQueue: [optional] a callback queue to perform the action on. Will perform on the current queue if not provided. Defaults to nil.
+  ///   - completion: [optional] a completion block to fire when the read-write transaction completes. Defaults to nil.
+  public func withinReadWriteTransaction<T>(_ body: @escaping (ReadWriteTransaction) throws -> T,
+                                            callbackQueue: DispatchQueue? = nil,
+                                            completion: ((Result<T, Error>) -> Void)? = nil) {
+    _ = self.withinReadWriteTransactionPromise {
+        Promise(fulfilled: try body($0))
+      }
+      .andThen { object in
+        DispatchQueue.apollo_returnResultAsyncIfNeeded(on: callbackQueue,
+                                                       action: completion,
+                                                       result: .success(object))
+      }
+      .catch { error in
+        DispatchQueue.apollo_returnResultAsyncIfNeeded(on: callbackQueue,
+                                                       action: completion,
+                                                       result: .failure(error))
+      }
   }
 
-  public func load<Query: GraphQLQuery>(query: Query) -> Promise<GraphQLResult<Query.Data>> {
-    return withinReadTransaction { transaction in
+  func load<Query: GraphQLQuery>(query: Query) -> Promise<GraphQLResult<Query.Data>> {
+    return withinReadTransactionPromise { transaction in
       let mapper = GraphQLSelectionSetMapper<Query.Data>()
       let dependencyTracker = GraphQLDependencyTracker()
 
@@ -152,7 +188,7 @@ public final class ApolloStore {
     fileprivate let cache: NormalizedCache
     fileprivate let cacheKeyForObject: CacheKeyForObject?
 
-    fileprivate lazy var loader: DataLoader<CacheKey, Record?> = DataLoader(self.cache.loadRecords)
+    fileprivate lazy var loader: DataLoader<CacheKey, Record?> = DataLoader(self.cache.loadRecordsPromise)
 
     init(cache: NormalizedCache, cacheKeyForObject: CacheKeyForObject?) {
       self.cache = cache
@@ -168,8 +204,12 @@ public final class ApolloStore {
       return try execute(selections: type.selections, onObjectWithKey: key, variables: variables, accumulator: mapper).await()
     }
 
-    public func loadRecords(forKeys keys: [CacheKey]) -> Promise<[Record?]> {
-      return cache.loadRecords(forKeys: keys)
+    public func loadRecords(forKeys keys: [CacheKey],
+                            callbackQueue: DispatchQueue = .main,
+                            completion: @escaping (Result<[Record?], Error>) -> Void) {
+      self.cache.loadRecords(forKeys: keys,
+                             callbackQueue: callbackQueue,
+                             completion: completion)
     }
 
     private final func complete(value: Any?) -> ResultOrPromise<JSONValue?> {
@@ -249,7 +289,7 @@ public final class ApolloStore {
 
       _ = try executor.execute(selections: selections, on: object, withKey: key, variables: variables, accumulator: normalizer)
       .flatMap {
-        self.cache.merge(records: $0)
+        self.cache.mergePromise(records: $0)
       }.andThen { changedKeys in
         if let didChangeKeysFunc = self.updateChangedKeysFunc {
           didChangeKeysFunc(changedKeys, nil)
@@ -258,3 +298,48 @@ public final class ApolloStore {
     }
   }
 }
+
+internal extension NormalizedCache {
+  func loadRecordsPromise(forKeys keys: [CacheKey]) -> Promise<[Record?]> {
+    return Promise { fulfill, reject in
+      self.loadRecords(
+        forKeys: keys,
+        callbackQueue: nil) { result in
+          switch result {
+          case .success(let records):
+            fulfill(records)
+          case .failure(let error):
+            reject(error)
+          }
+        }
+    }
+  }
+  
+  func mergePromise(records: RecordSet) -> Promise<Set<CacheKey>> {
+    return Promise { fulfill, reject in
+      self.merge(
+        records: records,
+        callbackQueue: nil) { result in
+          switch result {
+          case .success(let cacheKeys):
+            fulfill(cacheKeys)
+          case .failure(let error):
+            reject(error)
+          }
+      }
+    }
+  }
+  
+  func clearPromise() -> Promise<Void> {
+    return Promise { fulfill, reject in
+      self.clear(callbackQueue: nil) { result in
+        switch result {
+        case .success(let success):
+          fulfill(success)
+        case .failure(let error):
+          reject(error)
+        }
+      }
+    }
+  }
+}

Sources/Apollo/DispatchQueue+Optional.swift

@@ -0,0 +1,34 @@
+//
+//  DispatchQueue+Optional.swift
+//  Apollo
+//
+//  Created by Ellen Shapiro on 8/13/19.
+//  Copyright © 2019 Apollo GraphQL. All rights reserved.
+//
+
+import Foundation
+
+public extension DispatchQueue {
+  
+  static func apollo_performAsyncIfNeeded(on callbackQueue: DispatchQueue?, action: @escaping () -> Void) {
+    if let callbackQueue = callbackQueue {
+      // A callback queue was provided, perform the action on that queue
+      callbackQueue.async {
+        action()
+      }
+    } else {
+      // Perform the action on the current queue
+      action()
+    }
+  }
+  
+  static func apollo_returnResultAsyncIfNeeded<T>(on callbackQueue: DispatchQueue?, action: ((Result<T, Error>) -> Void)?, result: Result<T, Error>) {
+    guard let action = action else {
+      return
+    }
+    
+    self.apollo_performAsyncIfNeeded(on: callbackQueue) {
+      action(result)
+    }
+  }
+}

Sources/Apollo/InMemoryNormalizedCache.swift

@@ -4,18 +4,35 @@ public final class InMemoryNormalizedCache: NormalizedCache {
   public init(records: RecordSet = RecordSet()) {
     self.records = records
   }
-
-  public func loadRecords(forKeys keys: [CacheKey]) -> Promise<[Record?]> {
+  
+  public func loadRecords(forKeys keys: [CacheKey],
+                          callbackQueue: DispatchQueue?,
+                          completion: @escaping (Result<[Record?], Error>) -> Void) {
     let records = keys.map { self.records[$0] }
-    return Promise(fulfilled: records)
+    DispatchQueue.apollo_returnResultAsyncIfNeeded(on: callbackQueue,
+                                                   action: completion,
+                                                   result: .success(records))
   }
-
-  public func merge(records: RecordSet) -> Promise<Set<CacheKey>> {
-    return Promise(fulfilled: self.records.merge(records: records))
+  
+  public func merge(records: RecordSet,
+                    callbackQueue: DispatchQueue?,
+                    completion: @escaping (Result<Set<CacheKey>, Error>) -> Void) {
+    let cacheKeys = self.records.merge(records: records)
+    DispatchQueue.apollo_returnResultAsyncIfNeeded(on: callbackQueue,
+                                                   action: completion,
+                                                   result: .success(cacheKeys))
   }
 
-  public func clear() -> Promise<Void> {
-    records.clear()
-    return Promise(fulfilled: ())
+  public func clear(callbackQueue: DispatchQueue?,
+                    completion: ((Result<Void, Error>) -> Void)?) {
+    self.records.clear()
+    
+    guard let completion = completion else {
+      return
+    }
+    
+    DispatchQueue.apollo_returnResultAsyncIfNeeded(on: callbackQueue,
+                                                   action: completion,
+                                                   result: .success(()))
   }
 }

Sources/Apollo/NormalizedCache.swift

@@ -1,16 +1,31 @@
 public protocol NormalizedCache {
-
+  
   /// Loads records corresponding to the given keys.
-  /// - returns: A promise that fulfills with an array, with each index containing either the
-  ///            record corresponding to the key at that index or nil if not found.
-  func loadRecords(forKeys keys: [CacheKey]) -> Promise<[Record?]>
-
+  ///
+  /// - Parameters:
+  ///   - keys: The cache keys to load data for
+  ///   - callbackQueue: [optional] An alternate queue to fire the completion closure on. If nil, will fire on the current queue.
+  ///   - completion: A completion closure to fire when the load has completed. If successful, will contain an array. Each index will contain either the record corresponding to the key at the same index in the passed-in array of cache keys, or nil if that record was not found.
+  func loadRecords(forKeys keys: [CacheKey],
+                   callbackQueue: DispatchQueue?,
+                   completion: @escaping (Result<[Record?], Error>) -> Void)
+  
   /// Merges a set of records into the cache.
-  /// - returns: A promise that fulfills with a set of keys corresponding to *fields* that have
-  ///            changed (i.e. QUERY_ROOT.Foo.myField). These are the same type of keys as are 
-  ///            returned by RecordSet.merge(records:).
-  func merge(records: RecordSet) -> Promise<Set<CacheKey>>
+  ///
+  /// - Parameters:
+  ///   - records: The set of records to merge.
+  ///   - callbackQueue: [optional] An alternate queue to fire the completion closure on. If nil, will fire on the current queue.
+  ///   - completion: A completion closure to fire when the merge has completed. If successful, will contain a set of keys corresponding to *fields* that have changed (i.e. QUERY_ROOT.Foo.myField). These are the same type of keys as are returned by RecordSet.merge(records:).
+  func merge(records: RecordSet,
+             callbackQueue: DispatchQueue?,
+             completion: @escaping (Result<Set<CacheKey>, Error>) -> Void)
 
   // Clears all records
-  func clear() -> Promise<Void>
+  ///
+  /// - Parameters:
+  ///   - callbackQueue: [optional] An alternate queue to fire the completion closure on. If nil, will fire on the current queue.
+  ///   - completion: [optional] A completion closure to fire when the clear function has completed.
+  func clear(callbackQueue: DispatchQueue?,
+             completion: ((Result<Void, Error>) -> Void)?)
 }
+