firestore::local::MemoryDocumentOverlayCache added. (#9330)

Author: dconeybe

Firestore/Example/Firestore.xcodeproj/project.pbxproj

@@ -0,0 +1,110 @@
+/*
+ * 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 FIRESTORE_CORE_SRC_LOCAL_DOCUMENT_OVERLAY_CACHE_H_
+#define FIRESTORE_CORE_SRC_LOCAL_DOCUMENT_OVERLAY_CACHE_H_
+
+#include <cstdlib>
+#include <string>
+#include <unordered_map>
+
+#include "Firestore/core/src/model/document_key.h"
+#include "Firestore/core/src/model/mutation.h"
+#include "Firestore/core/src/model/mutation/overlay.h"
+#include "Firestore/core/src/model/resource_path.h"
+#include "absl/types/optional.h"
+
+namespace firebase {
+namespace firestore {
+namespace local {
+
+/**
+ * Provides methods to read and write document overlays.
+ *
+ * An overlay is a saved `Mutation`, that gives a local view of a document when
+ * applied to the remote version of the document.
+ *
+ * Each overlay stores the largest batch ID that is included in the overlay,
+ * which allows us to remove the overlay once all batches leading up to it have
+ * been acknowledged.
+ */
+class DocumentOverlayCache {
+ public:
+  using OverlayByDocumentKeyMap = std::unordered_map<model::DocumentKey,
+                                                     model::mutation::Overlay,
+                                                     model::DocumentKeyHash>;
+  using MutationByDocumentKeyMap = std::unordered_map<model::DocumentKey,
+                                                      model::Mutation,
+                                                      model::DocumentKeyHash>;
+
+  virtual ~DocumentOverlayCache() = default;
+
+  /**
+   * Gets the saved overlay mutation for the given document key.
+   *
+   * Returns an empty optional if there is no overlay for that key.
+   */
+  virtual absl::optional<model::mutation::Overlay> GetOverlay(
+      const model::DocumentKey& key) const = 0;
+
+  /**
+   * Saves the given document key to mutation map to persistence as overlays.
+   *
+   * All overlays will have their largest batch id set to `largestBatchId`.
+   */
+  virtual void SaveOverlays(int largest_batch_id,
+                            const MutationByDocumentKeyMap& overlays) = 0;
+
+  /** Removes the overlay whose largest-batch-id equals to the given ID. */
+  virtual void RemoveOverlaysForBatchId(int batch_id) = 0;
+
+  /**
+   * Returns all saved overlays for the given collection.
+   *
+   * @param collection The collection path to get the overlays for.
+   * @param since_batch_id The minimum batch ID to filter by (exclusive).
+   *     Only overlays that contain a change past `sinceBatchId` are returned.
+   * @return Mapping of each document key in the collection to its overlay.
+   */
+  virtual OverlayByDocumentKeyMap GetOverlays(
+      const model::ResourcePath& collection, int since_batch_id) const = 0;
+
+  /**
+   * Returns `count` overlays with a batch ID higher than `sinceBatchId` for the
+   * provided collection group, processed by ascending batch ID.
+   *
+   * This method always returns all overlays for a batch even if the last batch
+   * contains more documents than the remaining limit.
+   *
+   * @param collection_group The collection group to get the overlays for.
+   * @param since_batch_id The minimum batch ID to filter by (exclusive).
+   *     Only overlays that contain a change past `sinceBatchId` are returned.
+   * @param count The number of overlays to return. Can be exceeded if the last
+   *     batch contains more entries.
+   * @return Mapping of each document key in the collection group to its
+   * overlay.
+   */
+  virtual OverlayByDocumentKeyMap GetOverlays(
+      const std::string& collection_group,
+      int since_batch_id,
+      std::size_t count) const = 0;
+};
+
+}  // namespace local
+}  // namespace firestore
+}  // namespace firebase
+
+#endif  // FIRESTORE_CORE_SRC_LOCAL_DOCUMENT_OVERLAY_CACHE_H_

Firestore/core/src/local/document_overlay_cache.h

@@ -0,0 +1,69 @@
+/*
+ * 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.
+ */
+
+#include "Firestore/core/src/local/leveldb_document_overlay_cache.h"
+
+namespace firebase {
+namespace firestore {
+namespace local {
+
+using model::DocumentKey;
+using model::Mutation;
+using model::ResourcePath;
+using model::mutation::Overlay;
+
+// TODO(dconeybe) Implement these methods.
+
+LevelDbDocumentOverlayCache::LevelDbDocumentOverlayCache() {
+}
+
+absl::optional<Overlay> LevelDbDocumentOverlayCache::GetOverlay(
+    const DocumentKey& key) const {
+  (void)key;
+  return absl::nullopt;
+}
+
+void LevelDbDocumentOverlayCache::SaveOverlays(
+    int largest_batch_id, const MutationByDocumentKeyMap& overlays) {
+  (void)largest_batch_id;
+  (void)overlays;
+}
+
+void LevelDbDocumentOverlayCache::RemoveOverlaysForBatchId(int batch_id) {
+  (void)batch_id;
+}
+
+DocumentOverlayCache::OverlayByDocumentKeyMap
+LevelDbDocumentOverlayCache::GetOverlays(const ResourcePath& collection,
+                                         int since_batch_id) const {
+  (void)collection;
+  (void)since_batch_id;
+  return {};
+}
+
+DocumentOverlayCache::OverlayByDocumentKeyMap
+LevelDbDocumentOverlayCache::GetOverlays(const std::string& collection_group,
+                                         int since_batch_id,
+                                         std::size_t count) const {
+  (void)collection_group;
+  (void)since_batch_id;
+  (void)count;
+  return {};
+}
+
+}  // namespace local
+}  // namespace firestore
+}  // namespace firebase

Firestore/core/src/local/leveldb_document_overlay_cache.cc

@@ -0,0 +1,61 @@
+/*
+ * 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 FIRESTORE_CORE_SRC_LOCAL_LEVELDB_DOCUMENT_OVERLAY_CACHE_H_
+#define FIRESTORE_CORE_SRC_LOCAL_LEVELDB_DOCUMENT_OVERLAY_CACHE_H_
+
+#include <cstdlib>
+#include <string>
+
+#include "Firestore/core/src/local/document_overlay_cache.h"
+
+namespace firebase {
+namespace firestore {
+namespace local {
+
+class LevelDbDocumentOverlayCache final : public DocumentOverlayCache {
+ public:
+  LevelDbDocumentOverlayCache();
+
+  LevelDbDocumentOverlayCache(const LevelDbDocumentOverlayCache&) = delete;
+  LevelDbDocumentOverlayCache& operator=(const LevelDbDocumentOverlayCache&) =
+      delete;
+
+  LevelDbDocumentOverlayCache(LevelDbDocumentOverlayCache&&) = delete;
+  LevelDbDocumentOverlayCache& operator=(LevelDbDocumentOverlayCache&&) =
+      delete;
+
+  absl::optional<model::mutation::Overlay> GetOverlay(
+      const model::DocumentKey& key) const override;
+
+  void SaveOverlays(int largest_batch_id,
+                    const MutationByDocumentKeyMap& overlays) override;
+
+  void RemoveOverlaysForBatchId(int batch_id) override;
+
+  OverlayByDocumentKeyMap GetOverlays(const model::ResourcePath& collection,
+                                      int since_batch_id) const override;
+
+  OverlayByDocumentKeyMap GetOverlays(const std::string& collection_group,
+                                      int since_batch_id,
+                                      std::size_t count) const override;
+};
+
+}  // namespace local
+}  // namespace firestore
+}  // namespace firebase
+
+#endif  // FIRESTORE_CORE_SRC_LOCAL_LEVELDB_DOCUMENT_OVERLAY_CACHE_H_

Firestore/core/src/local/leveldb_document_overlay_cache.h

@@ -253,6 +253,13 @@ LevelDbBundleCache* LevelDbPersistence::bundle_cache() {
   return bundle_cache_.get();
 }
 
+LevelDbDocumentOverlayCache* LevelDbPersistence::document_overlay_cache(
+    const User& user) {
+  // TODO(dconeybe) Implement this once LevelDbDocumentOverlayCache is done.
+  (void)user;
+  return nullptr;
+}
+
 void LevelDbPersistence::RunInternal(absl::string_view label,
                                      std::function<void()> block) {
   HARD_ASSERT(transaction_ == nullptr,

Firestore/core/src/local/leveldb_persistence.cc

@@ -23,6 +23,7 @@
 
 #include "Firestore/core/src/credentials/user.h"
 #include "Firestore/core/src/local/leveldb_bundle_cache.h"
+#include "Firestore/core/src/local/leveldb_document_overlay_cache.h"
 #include "Firestore/core/src/local/leveldb_index_manager.h"
 #include "Firestore/core/src/local/leveldb_lru_reference_delegate.h"
 #include "Firestore/core/src/local/leveldb_mutation_queue.h"
@@ -80,6 +81,9 @@ class LevelDbPersistence : public Persistence {
 
   LevelDbBundleCache* bundle_cache() override;
 
+  LevelDbDocumentOverlayCache* document_overlay_cache(
+      const credentials::User& user) override;
+
   LevelDbMutationQueue* GetMutationQueueForUser(
       const credentials::User& user) override;