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Refactor Backend class states

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The states are now internal to the Backend class. This simplifies the use
of the class by moving the burder of state tracking to the class
itself.

Refactored the way the schemarouter uses the Backend class.

Also fixed a memory leak in the schemarouter when `ignore_databases_regex`
was used..
This commit is contained in:
Markus Mäkelä
2017-06-13 22:36:08 +03:00
parent bbfd9ce136
commit 18993bc8ca
3 changed files with 137 additions and 102 deletions
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98
include/maxscale/backend.hh
View File

@ -24,22 +24,31 @@
namespace maxscale
{
/**
* The state of the backend server reference
*/
enum bref_state
{
BREF_IN_USE = 0x01,
BREF_WAITING_RESULT = 0x02, /**< for session commands only */
BREF_QUERY_ACTIVE = 0x04, /**< for other queries */
BREF_CLOSED = 0x08,
};
class Backend
{
Backend(const Backend&);
Backend& operator =(const Backend&);
public:
/**
* How is the backend being closed
*/
enum close_type
{
NORMAL,
FATAL
};
/**
* What type of a response we expect from the backend
*/
enum response_type
{
EXPECT_RESPONSE,
NO_RESPONSE
};
/**
* @brief Create new Backend
*
@ -81,20 +90,6 @@ public:
*/
size_t session_command_count() const;
/**
* @brief Clear state
*
* @param state State to clear
*/
void clear_state(enum bref_state state);
/**
* @brief Set state
*
* @param state State to set
*/
void set_state(enum bref_state state);
/**
* @brief Get pointer to server reference
*
@ -116,7 +111,7 @@ public:
*
* This will close all active connections created by the backend.
*/
void close();
void close(close_type type = NORMAL);
/**
* @brief Get a pointer to the internal DCB
@ -128,11 +123,26 @@ public:
/**
* @brief Write data to the backend server
*
* @param buffer Buffer containing the data to write
* @param buffer Buffer containing the data to write
* @param expect_response Whether to expect a response to the query
*
* @return True if data was written successfully
*/
bool write(GWBUF* buffer);
bool write(GWBUF* buffer, response_type type = EXPECT_RESPONSE);
/**
* @brief Write an authentication switch request to the backend server
*
* @param buffer Buffer containing the authentication switch request
*
* @return True if request was successfully written
*/
bool auth(GWBUF* buffer);
/**
* @brief Mark that a reply to a query was received and processed
*/
void ack_write();
/**
* @brief Store a command
@ -165,13 +175,6 @@ public:
*/
bool is_waiting_result() const;
/**
* @brief Check if a query is active
*
* @return True if a query is active
*/
bool is_query_active() const;
/**
* @brief Check if the backend is closed
*
@ -180,10 +183,35 @@ public:
bool is_closed() const;
private:
/**
* Internal state of the backend
*/
enum backend_state
{
IN_USE = 0x01, /**< Backend has been taken into use */
WAITING_RESULT = 0x02, /**< Waiting for a reply */
CLOSED = 0x04, /**< Backend is no longer in use */
FATAL_FAILURE = 0x08 /**< Backend references that should be dropped */
};
/**
* @brief Clear state
*
* @param state State to clear
*/
void clear_state(backend_state state);
/**
* @brief Set state
*
* @param state State to set
*/
void set_state(backend_state state);
bool m_closed; /**< True if a connection has been opened and closed */
SERVER_REF* m_backend; /**< Backend server */
DCB* m_dcb; /**< Backend DCB */
int m_num_result_wait; /**< Number of not yet received results */
mxs::Buffer m_pending_cmd; /**< Pending commands */
int m_state; /**< State of the backend */
SessionCommandList m_session_commands; /**< List of session commands that are