Github user zuyu commented on a diff in the pull request:
https://github.com/apache/incubator-quickstep/pull/325#discussion_r153020141
--- Diff: transaction/CompatibilityChecker.hpp ---
@@ -0,0 +1,106 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you 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 QUICKSTEP_TRANSACTION_TRANSACTION_COMPATIBILITY_CHECKER_HPP_
+#define QUICKSTEP_TRANSACTION_TRANSACTION_COMPATIBILITY_CHECKER_HPP_
+
+#include <utility>
+#include <vector>
+
+#include "transaction/TransactionTable.hpp"
+#include "utility/Macros.hpp"
+
+namespace quickstep {
+
+class CatalogRelation;
+
+namespace transaction {
+
+/**
+ * @brief A class that checks the compatibility of a transaction with the
+ * other running transactions.
+ */
+class CompatibilityChecker {
+ public:
+ /**
+ * @brief Constructor
+ * @param transaction_table A lookup table that stores information about
+ * all the running and waiting transactions.
+ */
+ CompatibilityChecker(TransactionTable *transaction_table) {}
+
+ virtual ~CompatibilityChecker() {}
+
+ /**
+ * @brief Check if the given transaction is compatible with other
+ * running transactions.
+ * @note The transaction table has the list of all the running or pending
+ * transactions. Lookup the table and check if the given
transaction
+ * is compatible, based on the CC protocol specifications.
+ * @note Accesses to the transaction_table may need protection.
+
+ * @param tid The ID of the given transaction
+ * @param resource_requests A vector of pairs such that each pair has a
+ * resource ID and its requested access mode.
+ * @return True if the transaction is compatible and false if it is not.
+ */
+ virtual bool isTranasctionCompatible(const transaction_id tid,
+ const
std::vector<std::pair<ResourceId, AccessMode>> &resource_requests) {
+ return false;
+ }
+
+ /**
+ * @brief Check if the given transaction can acquire a Catalog lock on
the
+ * given relation.
+ * @param tid The ID of the given transaction.
+ * @param relation The given relation.
+ * @param access_mode The access_mode requested to lock the catalog.
+ * @return True if the lock can be acquired, false otherwise.
+ */
+ virtual bool canAcquireCatalogLock(const transaction_id tid,
+ const CatalogRelation &relation,
+ const AccessMode access_mode) {
+ return false;
+ }
+
+ /**
+ * @brief Check if the given transaction can acquire locks on all the
blocks
+ * of the given relation.
+ * @param tid The ID of the given transaction.
+ * @param rid The ID of the given relation.
+ * @param blocks The list of the blocks of the given relation.
+ * @param access_mode The access_mode requested to lock the blocks.
+ * @return True if the lock can be acquired, false otherwise.
+ */
+ virtual bool canAcquireBlockLocks(const transaction_id tid,
+ const relation_id rid,
+ const std::vector<block_id> &blocks,
+ const AccessMode access_mode) {
+ return false;
+ }
+
+ private:
+ DISALLOW_COPY_AND_ASSIGN(CompatibilityChecker);
+
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