Add IndexEntry (#9287)

* Add IndexEntry

* Tidy up includes.

* Add missing include for Hash

Author: wu-hui

Firestore/core/src/index/index_entry.cc

@@ -0,0 +1,56 @@
+/*
+ * 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/index/index_entry.h"
+
+#include "Firestore/core/src/util/hashing.h"
+#include "absl/strings/str_cat.h"
+
+namespace firebase {
+namespace firestore {
+namespace index {
+
+util::ComparisonResult IndexEntry::CompareTo(const IndexEntry& rhs) const {
+  util::ComparisonResult cmp = util::Compare(index_id(), rhs.index_id());
+  if (!util::Same(cmp)) return cmp;
+
+  cmp = util::Compare(document_key(), rhs.document_key());
+  if (!util::Same(cmp)) return cmp;
+
+  cmp = util::Compare(directional_value(), rhs.directional_value());
+  if (!util::Same(cmp)) return cmp;
+
+  return util::Compare(array_value(), rhs.array_value());
+}
+
+std::string IndexEntry::ToString() const {
+  return absl::StrCat("IndexEntry(", index_id(), ":", document_key().ToString(),
+                      " dir_val:", directional_value(),
+                      " array_val:", array_value(), ")");
+}
+
+std::ostream& operator<<(std::ostream& out, const IndexEntry& entry) {
+  return out << entry.ToString();
+}
+
+size_t IndexEntry::Hash() const {
+  return util::Hash(index_id(), document_key(), directional_value(),
+                    array_value());
+}
+
+}  // namespace index
+}  // namespace firestore
+}  // namespace firebase

Firestore/core/src/index/index_entry.h

@@ -0,0 +1,79 @@
+/*
+ * 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_INDEX_INDEX_ENTRY_H_
+#define FIRESTORE_CORE_SRC_INDEX_INDEX_ENTRY_H_
+
+#include <iostream>
+#include <memory>
+#include <string>
+#include <utility>
+
+#include "Firestore/core/src/model/document_key.h"
+#include "Firestore/core/src/util/comparison.h"
+
+namespace firebase {
+namespace firestore {
+namespace index {
+
+/** Represents an index entry saved by the SDK in its local storage. */
+class IndexEntry : public util::Comparable<IndexEntry> {
+ public:
+  IndexEntry(int32_t index_id,
+             model::DocumentKey key,
+             std::string array_value,
+             std::string directional_value)
+      : index_id_(index_id),
+        key_(std::move(key)),
+        array_value_(std::move(array_value)),
+        directional_value_(std::move(directional_value)) {
+  }
+
+  int32_t index_id() const {
+    return index_id_;
+  }
+
+  const model::DocumentKey& document_key() const {
+    return key_;
+  }
+
+  const std::string& array_value() const {
+    return array_value_;
+  }
+
+  const std::string& directional_value() const {
+    return directional_value_;
+  }
+
+  util::ComparisonResult CompareTo(const IndexEntry& rhs) const;
+  size_t Hash() const;
+
+  std::string ToString() const;
+  friend std::ostream& operator<<(std::ostream& out,
+                                  const IndexEntry& database_id);
+
+ private:
+  int32_t index_id_;
+  model::DocumentKey key_;
+  std::string array_value_;
+  std::string directional_value_;
+};
+
+}  // namespace index
+}  // namespace firestore
+}  // namespace firebase
+
+#endif  // FIRESTORE_CORE_SRC_INDEX_INDEX_ENTRY_H_