connection.h

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#ifndef ENGINE_SERVER_DATABASES_CONNECTION_H
#define ENGINE_SERVER_DATABASES_CONNECTION_H
 
#include "connection_pool.h"
 
#include <engine/shared/protocol.h>
 
#include <memory>
#include <optional>
 
enum
{
    // MAX_NAME_LENGTH includes the size with \0, which is not necessary in SQL
    MAX_NAME_LENGTH_SQL = MAX_NAME_LENGTH - 1,
};
 
// can hold one PreparedStatement with Results
class IDbConnection
{
public:
    IDbConnection(const char *pPrefix);
    virtual ~IDbConnection() = default;
    IDbConnection &operator=(const IDbConnection &) = delete;
    virtual void Print(const char *pMode) = 0;
 
    // returns the database prefix
    const char *GetPrefix() const { return m_aPrefix; }
    virtual const char *BinaryCollate() const = 0;
    // can be inserted into queries to convert a timestamp variable to the unix timestamp
    virtual void ToUnixTimestamp(const char *pTimestamp, char *aBuf, unsigned int BufferSize) = 0;
    // since MySQL automatically converts timestamps to utc, meanwhile sqlite code has to
    // explicitly convert before inserting timestamps, NOTE: CURRENT_TIMESTAMP in SQLite is UTC by
    // default and doesn't have to be converted
    virtual const char *InsertTimestampAsUtc() const = 0;
    // can be used in the context of `LIKE Map`, adds `? COLLATE`
    virtual const char *CollateNocase() const = 0;
    // syntax to insert a row into table or ignore if it already exists
    virtual const char *InsertIgnore() const = 0;
    // ORDER BY RANDOM()/RAND()
    virtual const char *Random() const = 0;
    virtual const char *False() const = 0;
    virtual const char *True() const = 0;
 
    // tries to allocate the connection from the pool established
    //
    // returns true on success
    virtual bool Connect(char *pError, int ErrorSize) = 0;
    // has to be called to return the connection back to the pool
    virtual void Disconnect() = 0;
 
    // ? for Placeholders, connection has to be established, can overwrite previous prepared statements
    //
    // returns true on success
    virtual bool PrepareStatement(const char *pStmt, char *pError, int ErrorSize) = 0;
 
    // PrepareStatement has to be called beforehand,
    virtual void BindString(int Idx, const char *pString) = 0;
    virtual void BindBlob(int Idx, unsigned char *pBlob, int Size) = 0;
    virtual void BindInt(int Idx, int Value) = 0;
    virtual void BindInt64(int Idx, int64_t Value) = 0;
    virtual void BindFloat(int Idx, float Value) = 0;
    virtual void BindNull(int Idx) = 0;
 
    // Print expanded sql statement
    virtual void Print() = 0;
 
    // executes the query and returns if a result row exists and selects it
    // when called multiple times the next row is selected
    //
    // returns true on success
    virtual bool Step(bool *pEnd, char *pError, int ErrorSize) = 0;
    // executes the query and returns the number of rows affected by the update/insert/delete
    //
    // returns true on success
    virtual bool ExecuteUpdate(int *pNumUpdated, char *pError, int ErrorSize) = 0;
 
    virtual bool IsNull(int Col) = 0;
    virtual float GetFloat(int Col) = 0;
    virtual int GetInt(int Col) = 0;
    virtual int64_t GetInt64(int Col) = 0;
    // ensures that the string is null terminated
    virtual void GetString(int Col, char *pBuffer, int BufferSize) = 0;
    // returns number of bytes read into the buffer
    virtual int GetBlob(int Col, unsigned char *pBuffer, int BufferSize) = 0;
    std::optional<float> GetOptionalFloat(int Col);
    std::optional<int> GetOptionalInt(int Col);
    std::optional<int64_t> GetOptionalInt64(int Col);
 
    // SQL statements, that can't be abstracted, has side effects to the result
    virtual bool AddPoints(const char *pPlayer, int Points, char *pError, int ErrorSize) = 0;
 
private:
    char m_aPrefix[64];
 
protected:
    void FormatCreateRace(char *aBuf, unsigned int BufferSize, bool Backup) const;
    void FormatCreateTeamrace(char *aBuf, unsigned int BufferSize, const char *pIdType, bool Backup) const;
    void FormatCreateMaps(char *aBuf, unsigned int BufferSize) const;
    void FormatCreateSaves(char *aBuf, unsigned int BufferSize, bool Backup) const;
    void FormatCreatePoints(char *aBuf, unsigned int BufferSize) const;
};
 
bool MysqlAvailable();
int MysqlInit();
void MysqlUninit();
 
std::unique_ptr<IDbConnection> CreateSqliteConnection(const char *pFilename, bool Setup);
// Returns nullptr if MySQL support is not compiled in.
std::unique_ptr<IDbConnection> CreateMysqlConnection(CMysqlConfig Config);
 
#endif // ENGINE_SERVER_DATABASES_CONNECTION_H