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124 lines
3.7 KiB
124 lines
3.7 KiB
#ifndef PGSQL_EXPLICIT_TRANSACTION_STATE_MANAGER_H
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#define PGSQL_EXPLICIT_TRANSACTION_STATE_MANAGER_H
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#include <string>
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#include <vector>
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#include <algorithm>
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#include "proxysql.h"
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#include "cpp.h"
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#include "PgSQL_Connection.h"
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#ifndef PROXYJSON
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#define PROXYJSON
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#include "../deps/json/json_fwd.hpp"
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#endif // PROXYJSON
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/**
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* @struct PgSQL_Variable_Snapshot
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* @brief Represents a snapshot of PostgreSQL variables during a transaction.
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*
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* This structure is used to store the state of PostgreSQL variables, including
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* their values and hash representations, at a specific point in time during a transaction.
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*/
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struct PgSQL_Variable_Snapshot {
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char* var_value[PGSQL_NAME_LAST_HIGH_WM] = {}; // Not using smart pointers because we need fine-grained control over hashing when values change
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uint32_t var_hash[PGSQL_NAME_LAST_HIGH_WM] = {};
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};
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/**
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* @struct TxnCmd
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* @brief Represents a transaction command type begin executed and its associated metadata.
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*
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*/
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struct TxnCmd {
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/**
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* @enum Type
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* @brief Enumerates the types of transaction commands.
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*/
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enum Type {
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UNKNOWN = -1,
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BEGIN,
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COMMIT,
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ROLLBACK,
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SAVEPOINT,
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RELEASE,
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ROLLBACK_TO,
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ROLLBACK_AND_CHAIN
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} type = Type::UNKNOWN;
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std::string savepoint; //< The name of the savepoint, if applicable.
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};
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/**
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* @class PgSQL_TxnCmdParser
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* @brief Parses transaction-related commands for PostgreSQL.
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*
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* This class is responsible for tokenizing and interpreting transaction-related
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* commands such as BEGIN, COMMIT, ROLLBACK, SAVEPOINT, etc.
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*/
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class PgSQL_TxnCmdParser {
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public:
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PgSQL_TxnCmdParser() noexcept { tokens.reserve(16); }
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~PgSQL_TxnCmdParser() noexcept = default;
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TxnCmd parse(std::string_view input, bool in_transaction_mode) noexcept;
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private:
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std::vector<std::string_view> tokens;
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TxnCmd parse_rollback(size_t& pos) noexcept;
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TxnCmd parse_savepoint(size_t& pos) noexcept;
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TxnCmd parse_release(size_t& pos) noexcept;
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TxnCmd parse_start(size_t& pos) noexcept;
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// Helpers
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inline static bool iequals(std::string_view a, std::string_view b) noexcept {
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if (a.size() != b.size()) return false;
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for (size_t i = 0; i < a.size(); ++i) {
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char ca = a[i];
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char cb = b[i];
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if (ca >= 'A' && ca <= 'Z') ca += 32;
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if (cb >= 'A' && cb <= 'Z') cb += 32;
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if (ca != cb) return false;
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}
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return true;
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}
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inline static bool contains(std::vector<std::string_view>&& list, std::string_view value) noexcept {
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for (const auto& item : list) if (iequals(item, value)) return true;
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return false;
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}
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};
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/**
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* @class PgSQL_ExplicitTxnStateMgr
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* @brief Manages the state of explicit transactions in PostgreSQL.
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*
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* This class is responsible for handling explicit transaction commands such as
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* BEGIN, COMMIT, ROLLBACK, SAVEPOINT, and managing the associated state.
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*/
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class PgSQL_ExplicitTxnStateMgr {
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public:
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PgSQL_ExplicitTxnStateMgr(PgSQL_Session* sess);
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~PgSQL_ExplicitTxnStateMgr();
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bool handle_transaction(std::string_view input);
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int get_savepoint_count() const { return savepoint.size(); }
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void fill_internal_session(nlohmann::json& j);
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private:
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PgSQL_Session* session;
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std::vector<PgSQL_Variable_Snapshot> transaction_state;
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std::vector<std::string> savepoint;
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PgSQL_TxnCmdParser tx_parser;
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void start_transaction();
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void commit();
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void rollback(bool rollback_and_chain);
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bool add_savepoint(std::string_view name);
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bool rollback_to_savepoint(std::string_view name);
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bool release_savepoint(std::string_view name);
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static void reset_variable_snapshot(PgSQL_Variable_Snapshot& var_snapshot) noexcept;
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};
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#endif // PGSQL_EXPLICIT_TRANSACTION_STATE_MANAGER_H
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