Port FSTMemoryQueryCache to C++ (#2197)

Author: Greg Soltis

Firestore/Source/Local/FSTMemoryQueryCache.mm

@@ -18,6 +18,7 @@
 
 #import <Protobuf/GPBProtocolBuffers.h>
 
+#include <memory>
 #include <utility>
 
 #import "Firestore/Protos/objc/firestore/local/Target.pbobjc.h"
@@ -26,9 +27,12 @@
 #import "Firestore/Source/Local/FSTQueryData.h"
 #import "Firestore/Source/Local/FSTReferenceSet.h"
 
+#include "Firestore/core/src/firebase/firestore/local/memory_query_cache.h"
 #include "Firestore/core/src/firebase/firestore/model/document_key.h"
 #include "Firestore/core/src/firebase/firestore/model/snapshot_version.h"
+#include "absl/memory/memory.h"
 
+using firebase::firestore::local::MemoryQueryCache;
 using firebase::firestore::model::DocumentKey;
 using firebase::firestore::model::DocumentKeySet;
 using firebase::firestore::model::ListenSequenceNumber;
@@ -37,33 +41,13 @@
 
 NS_ASSUME_NONNULL_BEGIN
 
-@interface FSTMemoryQueryCache ()
-
-/** Maps a query to the data about that query. */
-@property(nonatomic, strong, readonly) NSMutableDictionary<FSTQuery *, FSTQueryData *> *queries;
-
-/** A ordered bidirectional mapping between documents and the remote target IDs. */
-@property(nonatomic, strong, readonly) FSTReferenceSet *references;
-
-/** The highest numbered target ID encountered. */
-@property(nonatomic, assign) TargetId highestTargetID;
-
-@property(nonatomic, assign) ListenSequenceNumber highestListenSequenceNumber;
-
-@end
-
 @implementation FSTMemoryQueryCache {
-  FSTMemoryPersistence *_persistence;
-  /** The last received snapshot version. */
-  SnapshotVersion _lastRemoteSnapshotVersion;
+  std::unique_ptr<MemoryQueryCache> _cache;
 }
 
 - (instancetype)initWithPersistence:(FSTMemoryPersistence *)persistence {
   if (self = [super init]) {
-    _persistence = persistence;
-    _queries = [NSMutableDictionary dictionary];
-    _references = [[FSTReferenceSet alloc] init];
-    _lastRemoteSnapshotVersion = SnapshotVersion::None();
+    _cache = absl::make_unique<MemoryQueryCache>(persistence);
   }
   return self;
 }
@@ -72,112 +56,74 @@ - (instancetype)initWithPersistence:(FSTMemoryPersistence *)persistence {
 #pragma mark Query tracking
 
 - (TargetId)highestTargetID {
-  return _highestTargetID;
+  return _cache->highest_target_id();
 }
 
 - (ListenSequenceNumber)highestListenSequenceNumber {
-  return _highestListenSequenceNumber;
+  return _cache->highest_listen_sequence_number();
 }
 
 - (const SnapshotVersion &)lastRemoteSnapshotVersion {
-  return _lastRemoteSnapshotVersion;
+  return _cache->last_remote_snapshot_version();
 }
 
 - (void)setLastRemoteSnapshotVersion:(SnapshotVersion)snapshotVersion {
-  _lastRemoteSnapshotVersion = std::move(snapshotVersion);
+  _cache->set_last_remote_snapshot_version(std::move(snapshotVersion));
 }
 
 - (void)addQueryData:(FSTQueryData *)queryData {
-  self.queries[queryData.query] = queryData;
-  if (queryData.targetID > self.highestTargetID) {
-    self.highestTargetID = queryData.targetID;
-  }
-  if (queryData.sequenceNumber > self.highestListenSequenceNumber) {
-    self.highestListenSequenceNumber = queryData.sequenceNumber;
-  }
+  _cache->AddTarget(queryData);
 }
 
 - (void)updateQueryData:(FSTQueryData *)queryData {
-  self.queries[queryData.query] = queryData;
-  if (queryData.targetID > self.highestTargetID) {
-    self.highestTargetID = queryData.targetID;
-  }
-  if (queryData.sequenceNumber > self.highestListenSequenceNumber) {
-    self.highestListenSequenceNumber = queryData.sequenceNumber;
-  }
+  _cache->UpdateTarget(queryData);
 }
 
 - (int32_t)count {
-  return (int32_t)[self.queries count];
+  return _cache->count();
 }
 
 - (void)removeQueryData:(FSTQueryData *)queryData {
-  [self.queries removeObjectForKey:queryData.query];
-  [self.references removeReferencesForID:queryData.targetID];
+  _cache->RemoveTarget(queryData);
 }
 
 - (nullable FSTQueryData *)queryDataForQuery:(FSTQuery *)query {
-  return self.queries[query];
+  return _cache->GetTarget(query);
 }
 
 - (void)enumerateTargetsUsingBlock:(void (^)(FSTQueryData *queryData, BOOL *stop))block {
-  [self.queries
-      enumerateKeysAndObjectsUsingBlock:^(FSTQuery *key, FSTQueryData *queryData, BOOL *stop) {
-        block(queryData, stop);
-      }];
+  _cache->EnumerateTargets(block);
 }
 
 - (int)removeQueriesThroughSequenceNumber:(ListenSequenceNumber)sequenceNumber
                               liveQueries:(NSDictionary<NSNumber *, FSTQueryData *> *)liveQueries {
-  NSMutableArray<FSTQuery *> *toRemove = [NSMutableArray array];
-  [self.queries
-      enumerateKeysAndObjectsUsingBlock:^(FSTQuery *query, FSTQueryData *queryData, BOOL *stop) {
-        if (queryData.sequenceNumber <= sequenceNumber) {
-          if (liveQueries[@(queryData.targetID)] == nil) {
-            [toRemove addObject:query];
-            [self.references removeReferencesForID:queryData.targetID];
-          }
-        }
-      }];
-  [self.queries removeObjectsForKeys:toRemove];
-  return (int)[toRemove count];
+  return _cache->RemoveTargets(sequenceNumber, liveQueries);
 }
 
 #pragma mark Reference tracking
 
 - (void)addMatchingKeys:(const DocumentKeySet &)keys forTargetID:(TargetId)targetID {
-  [self.references addReferencesToKeys:keys forID:targetID];
-  for (const DocumentKey &key : keys) {
-    [_persistence.referenceDelegate addReference:key];
-  }
+  _cache->AddMatchingKeys(keys, targetID);
 }
 
 - (void)removeMatchingKeys:(const DocumentKeySet &)keys forTargetID:(TargetId)targetID {
-  [self.references removeReferencesToKeys:keys forID:targetID];
-  for (const DocumentKey &key : keys) {
-    [_persistence.referenceDelegate removeReference:key];
-  }
+  _cache->RemoveMatchingKeys(keys, targetID);
 }
 
 - (void)removeMatchingKeysForTargetID:(TargetId)targetID {
-  [self.references removeReferencesForID:targetID];
+  _cache->RemoveAllKeysForTarget(targetID);
 }
 
 - (DocumentKeySet)matchingKeysForTargetID:(TargetId)targetID {
-  return [self.references referencedKeysForID:targetID];
+  return _cache->GetMatchingKeys(targetID);
 }
 
 - (BOOL)containsKey:(const firebase::firestore::model::DocumentKey &)key {
-  return [self.references containsKey:key];
+  return _cache->Contains(key);
 }
 
 - (size_t)byteSizeWithSerializer:(FSTLocalSerializer *)serializer {
-  __block size_t count = 0;
-  [self.queries
-      enumerateKeysAndObjectsUsingBlock:^(FSTQuery *key, FSTQueryData *queryData, BOOL *stop) {
-        count += [[serializer encodedQueryData:queryData] serializedSize];
-      }];
-  return count;
+  return _cache->CalculateByteSize(serializer);
 }
 
 @end

Firestore/core/src/firebase/firestore/local/memory_query_cache.h

@@ -0,0 +1,123 @@
+/*
+ * Copyright 2018 Google
+ *
+ * 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 FIRESTORE_CORE_SRC_FIREBASE_FIRESTORE_LOCAL_MEMORY_QUERY_CACHE_H_
+#define FIRESTORE_CORE_SRC_FIREBASE_FIRESTORE_LOCAL_MEMORY_QUERY_CACHE_H_
+
+#if !defined(__OBJC__)
+#error "For now, this file must only be included by ObjC source files."
+#endif  // !defined(__OBJC__)
+
+#import <Foundation/Foundation.h>
+
+#include <cstdint>
+#include <utility>
+
+#include "Firestore/core/src/firebase/firestore/model/document_key_set.h"
+#include "Firestore/core/src/firebase/firestore/model/snapshot_version.h"
+#include "Firestore/core/src/firebase/firestore/model/types.h"
+
+@class FSTLocalSerializer;
+@class FSTMemoryPersistence;
+@class FSTQuery;
+@class FSTQueryData;
+@class FSTReferenceSet;
+
+NS_ASSUME_NONNULL_BEGIN
+
+namespace firebase {
+namespace firestore {
+namespace local {
+
+typedef void (^TargetEnumerator)(FSTQueryData*, BOOL*);
+
+class MemoryQueryCache {
+ public:
+  explicit MemoryQueryCache(FSTMemoryPersistence* persistence);
+
+  // Target-related methods
+  void AddTarget(FSTQueryData* query_data);
+
+  void UpdateTarget(FSTQueryData* query_data);
+
+  void RemoveTarget(FSTQueryData* query_data);
+
+  FSTQueryData* _Nullable GetTarget(FSTQuery* query);
+
+  void EnumerateTargets(TargetEnumerator block);
+
+  int RemoveTargets(model::ListenSequenceNumber upper_bound,
+                    NSDictionary<NSNumber*, FSTQueryData*>* live_targets);
+
+  // Key-related methods
+  void AddMatchingKeys(const model::DocumentKeySet& keys,
+                       model::TargetId target_id);
+
+  void RemoveMatchingKeys(const model::DocumentKeySet& keys,
+                          model::TargetId target_id);
+
+  void RemoveAllKeysForTarget(model::TargetId target_id);
+
+  model::DocumentKeySet GetMatchingKeys(model::TargetId target_id);
+
+  bool Contains(const model::DocumentKey& key);
+
+  // Other methods and accessors
+  size_t CalculateByteSize(FSTLocalSerializer* serializer);
+
+  int32_t count() const {
+    return static_cast<int32_t>([queries_ count]);
+  }
+
+  model::ListenSequenceNumber highest_listen_sequence_number() const {
+    return highest_listen_sequence_number_;
+  }
+
+  model::TargetId highest_target_id() const {
+    return highest_target_id_;
+  }
+
+  const model::SnapshotVersion& last_remote_snapshot_version() const {
+    return last_remote_snapshot_version_;
+  }
+
+  void set_last_remote_snapshot_version(model::SnapshotVersion version) {
+    last_remote_snapshot_version_ = std::move(version);
+  }
+
+ private:
+  FSTMemoryPersistence* persistence_;
+  /** The highest sequence number encountered */
+  model::ListenSequenceNumber highest_listen_sequence_number_;
+  /** The highest numbered target ID encountered. */
+  model::TargetId highest_target_id_;
+  /** The last received snapshot version. */
+  model::SnapshotVersion last_remote_snapshot_version_;
+
+  /** Maps a query to the data about that query. */
+  NSMutableDictionary<FSTQuery*, FSTQueryData*>* queries_;
+  /** A ordered bidirectional mapping between documents and the remote target
+   * IDs. */
+  FSTReferenceSet* references_;
+};
+
+}  // namespace local
+}  // namespace firestore
+}  // namespace firebase
+
+NS_ASSUME_NONNULL_END
+
+#endif  // FIRESTORE_CORE_SRC_FIREBASE_FIRESTORE_LOCAL_MEMORY_QUERY_CACHE_H_