mysql.h

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#ifndef DBALLE_SQL_MYSQL_H
#define DBALLE_SQL_MYSQL_H
 
#include <cstdlib>
#include <dballe/sql/sql.h>
#include <functional>
#include <mysql.h>
#include <vector>
 
namespace dballe {
namespace sql {
struct MySQLStatement;

struct error_mysql : public error_db
{
    std::string msg;
 
    error_mysql(MYSQL* db, const std::string& msg);
    error_mysql(const std::string& dbmsg, const std::string& msg);
    ~error_mysql() throw() {}
 
    const char* what() const noexcept override { return msg.c_str(); }
 
    static void throwf(MYSQL* db, const char* fmt, ...)
        WREPORT_THROWF_ATTRS(2, 3);
};
 
namespace mysql {
 
struct ConnectInfo
{
    std::string host;
    std::string user;
    bool has_passwd = false;
    std::string passwd;
    bool has_dbname = false;
    std::string dbname;
    unsigned port = 0;
    std::string unix_socket;
 
    // Reset everything to defaults
    void reset();
    void parse_url(const std::string& url);
    // Modeled after
    // http://dev.mysql.com/doc/connector-j/en/connector-j-reference-configuration-properties.html
    std::string to_url() const;
};
 
struct Row
{
    MYSQL_RES* res = nullptr;
    MYSQL_ROW row  = nullptr;
 
    Row(MYSQL_RES* res, MYSQL_ROW row) : res(res), row(row) {}
 
    operator bool() const { return row != nullptr; }
    operator MYSQL_ROW() { return row; }
    operator MYSQL_ROW() const { return row; }
 
    int as_int(unsigned col) const { return strtol(row[col], 0, 10); }
    unsigned as_unsigned(unsigned col) const
    {
        return strtoul(row[col], 0, 10);
    }
    const char* as_cstring(unsigned col) const { return row[col]; }
    std::string as_string(unsigned col) const
    {
        return std::string(row[col], mysql_fetch_lengths(res)[col]);
    }
    std::vector<uint8_t> as_blob(unsigned col) const
    {
        return std::vector<uint8_t>(row[col],
                                    row[col] + mysql_fetch_lengths(res)[col]);
    }
    Datetime as_datetime(int col) const;
    bool isnull(unsigned col) const { return row[col] == nullptr; }
};
 
struct Result
{
    MYSQL_RES* res = nullptr;
 
    Result() : res(nullptr) {}
    Result(MYSQL_RES* res) : res(res) {}
    ~Result()
    {
        if (res)
            mysql_free_result(res);
    }

    Result(Result&& o) : res(o.res) { o.res = nullptr; }
    Result& operator=(Result&& o)
    {
        if (this == &o)
            return *this;
        if (res)
            mysql_free_result(res);
        res   = o.res;
        o.res = nullptr;
        return *this;
    }
 
    operator bool() const { return res != nullptr; }
 
    operator MYSQL_RES*() { return res; }
    operator const MYSQL_RES*() const { return res; }
 
    unsigned rowcount() const { return mysql_num_rows(res); }
    unsigned colcount() const { return mysql_num_fields(res); }

    Row expect_one_result();

    Row fetch() { return Row(res, mysql_fetch_row(res)); }
 
    // Prevent copy
    Result(const Result&)            = delete;
    Result& operator=(const Result&) = delete;
};
 
} // namespace mysql

class MySQLConnection : public Connection
{
protected:
    MYSQL* db   = nullptr;
    bool forked = false;
 
    void send_result(mysql::Result&& res,
                     std::function<void(const mysql::Row&)> dest);
 
protected:
    void init_after_connect();
 
    // See https://dev.mysql.com/doc/refman/5.0/en/mysql-real-connect.html
    void open(const mysql::ConnectInfo& info);
 
    MySQLConnection();
 
    void fork_prepare() override;
    void fork_parent() override;
    void fork_child() override;
 
    void check_connection();
 
public:
    MySQLConnection(const MySQLConnection&)  = delete;
    MySQLConnection(const MySQLConnection&&) = delete;
    ~MySQLConnection();
    MySQLConnection& operator=(const MySQLConnection&)  = delete;
    MySQLConnection& operator=(const MySQLConnection&&) = delete;
 
    static std::shared_ptr<MySQLConnection> create();
 
    operator MYSQL*() { return db; }
 
    // See
    // http://dev.mysql.com/doc/connector-j/en/connector-j-reference-configuration-properties.html
    void open_url(const std::string& url);
    void open_test();

    std::string escape(const char* str);
    std::string escape(const std::string& str);
    std::string escape(const std::vector<uint8_t>& str);

    void exec_no_data_nothrow(const char* query) noexcept;
    // Run a query, checking that it is successful and it gives no results
    void exec_no_data(const char* query);
    // Run a query, checking that it is successful and it gives no results
    void exec_no_data(const std::string& query);
    // Run a query, with a locally stored result
    mysql::Result exec_store(const char* query);
    // Run a query, with a locally stored result
    mysql::Result exec_store(const std::string& query);
    // Run a query, with a remotely fetched result
    void exec_use(const char* query,
                  std::function<void(const mysql::Row&)> dest);
    // Run a query, with a remotely fetched result
    void exec_use(const std::string& query,
                  std::function<void(const mysql::Row&)> dest);
 
    std::unique_ptr<Transaction> transaction(bool readonly = false) override;
    bool has_table(const std::string& name) override;
    std::string get_setting(const std::string& key) override;
    void set_setting(const std::string& key, const std::string& value) override;
    void drop_settings() override;
    void execute(const std::string& query) override;
    void explain(const std::string& query, FILE* out) override;

    void drop_table_if_exists(const char* name);

    int get_last_insert_id();
};
 
} // namespace sql
} // namespace dballe
#endif