old-nall/database/odbc.hpp
2016-05-15 12:42:10 +02:00

297 lines
11 KiB
C++

#pragma once
#include <nall/string.hpp>
#include <sql.h>
#include <sqltypes.h>
#include <sqlext.h>
namespace nall { namespace Database {
struct ODBC {
struct Statement {
Statement(const Statement& source) = delete;
auto operator=(const Statement& source) -> Statement& = delete;
Statement(SQLHANDLE statement) : _statement(statement) {}
Statement(Statement&& source) { operator=(move(source)); }
auto operator=(Statement&& source) -> Statement& {
_statement = source._statement;
_output = source._output;
_values = move(source._values);
source._statement = nullptr;
source._output = 0;
return *this;
}
auto columns() -> unsigned {
SQLSMALLINT columns = 0;
if(statement()) SQLNumResultCols(statement(), &columns);
return columns;
}
auto integer(unsigned column) -> int64_t {
if(auto value = _values(column)) return value.get<int64_t>(0);
int64_t value = 0;
SQLGetData(statement(), 1 + column, SQL_C_SBIGINT, &value, 0, nullptr);
_values(column) = (int64_t)value;
return value;
}
auto natural(unsigned column) -> uint64_t {
if(auto value = _values(column)) return value.get<uint64_t>(0);
uint64_t value = 0;
SQLGetData(statement(), 1 + column, SQL_C_UBIGINT, &value, 0, nullptr);
_values(column) = (uint64_t)value;
return value;
}
auto real(unsigned column) -> double {
if(auto value = _values(column)) return value.get<double>(0.0);
double value = 0.0;
SQLGetData(statement(), 1 + column, SQL_C_DOUBLE, &value, 0, nullptr);
_values(column) = (double)value;
return value;
}
auto text(unsigned column) -> string {
if(auto value = _values(column)) return value.get<string>({});
string value;
value.resize(65535);
SQLLEN size = 0;
SQLGetData(statement(), 1 + column, SQL_C_CHAR, value.get(), value.size(), &size);
value.resize(size);
_values(column) = (string)value;
return value;
}
auto data(unsigned column) -> vector<uint8_t> {
if(auto value = _values(column)) return value.get<vector<uint8_t>>({});
vector<uint8_t> value;
value.resize(65535);
SQLLEN size = 0;
SQLGetData(statement(), 1 + column, SQL_C_CHAR, value.data(), value.size(), &size);
value.resize(size);
_values(column) = (vector<uint8_t>)value;
return value;
}
auto integer() -> int64_t { return integer(_output++); }
auto natural() -> uint64_t { return natural(_output++); }
auto real() -> double { return real(_output++); }
auto text() -> string { return text(_output++); }
auto data() -> vector<uint8_t> { return data(_output++); }
protected:
virtual auto statement() -> SQLHANDLE { return _statement; }
SQLHANDLE _statement = nullptr;
unsigned _output = 0;
vector<any> _values; //some ODBC drivers (eg MS-SQL) do not allow the same column to be read more than once
};
struct Query : Statement {
Query(const Query& source) = delete;
auto operator=(const Query& source) -> Query& = delete;
Query(SQLHANDLE statement) : Statement(statement) {}
Query(Query&& source) : Statement(source._statement) { operator=(move(source)); }
~Query() {
if(statement()) {
SQLFreeHandle(SQL_HANDLE_STMT, _statement);
_statement = nullptr;
}
}
auto operator=(Query&& source) -> Query& {
Statement::operator=(move(source));
_bindings = move(source._bindings);
_result = source._result;
_input = source._input;
_stepped = source._stepped;
source._result = SQL_SUCCESS;
source._input = 0;
source._stepped = false;
return *this;
}
explicit operator bool() {
//this is likely not the best way to test if the query has returned data ...
//but I wasn't able to find an ODBC API for this seemingly simple task
return statement() && success();
}
//ODBC SQLBindParameter only holds pointers to data values
//if the bound paramters go out of scope before the query is executed, binding would reference dangling pointers
//so to work around this, we cache all parameters inside Query until the query is executed
auto& bind(unsigned column, nullptr_t) { return _bindings.append({column, any{(nullptr_t)nullptr}}), *this; }
auto& bind(unsigned column, int32_t value) { return _bindings.append({column, any{(int32_t)value}}), *this; }
auto& bind(unsigned column, uint32_t value) { return _bindings.append({column, any{(uint32_t)value}}), *this; }
auto& bind(unsigned column, int64_t value) { return _bindings.append({column, any{(int64_t)value}}), *this; }
auto& bind(unsigned column, uint64_t value) { return _bindings.append({column, any{(uint64_t)value}}), *this; }
auto& bind(unsigned column, double value) { return _bindings.append({column, any{(double)value}}), *this; }
auto& bind(unsigned column, const string& value) { return _bindings.append({column, any{(string)value}}), *this; }
auto& bind(unsigned column, const vector<uint8_t>& value) { return _bindings.append({column, any{(vector<uint8_t>)value}}), *this; }
auto& bind(nullptr_t) { return bind(_input++, nullptr); }
auto& bind(int32_t value) { return bind(_input++, value); }
auto& bind(uint32_t value) { return bind(_input++, value); }
auto& bind(int64_t value) { return bind(_input++, value); }
auto& bind(uint64_t value) { return bind(_input++, value); }
auto& bind(double value) { return bind(_input++, value); }
auto& bind(const string& value) { return bind(_input++, value); }
auto& bind(const vector<uint8_t>& value) { return bind(_input++, value); }
auto step() -> bool {
if(!_stepped) {
for(auto& binding : _bindings) {
if(binding.value.is<nullptr_t>()) {
SQLLEN length = SQL_NULL_DATA;
SQLBindParameter(_statement, 1 + binding.column, SQL_PARAM_INPUT, SQL_C_NUMERIC, SQL_NUMERIC, 0, 0, nullptr, 0, &length);
} else if(binding.value.is<int32_t>()) {
SQLBindParameter(_statement, 1 + binding.column, SQL_PARAM_INPUT, SQL_C_SLONG, SQL_INTEGER, 0, 0, &binding.value.get<int32_t>(), 0, nullptr);
} else if(binding.value.is<uint32_t>()) {
SQLBindParameter(_statement, 1 + binding.column, SQL_PARAM_INPUT, SQL_C_ULONG, SQL_INTEGER, 0, 0, &binding.value.get<uint32_t>(), 0, nullptr);
} else if(binding.value.is<int64_t>()) {
SQLBindParameter(_statement, 1 + binding.column, SQL_PARAM_INPUT, SQL_C_SBIGINT, SQL_INTEGER, 0, 0, &binding.value.get<int64_t>(), 0, nullptr);
} else if(binding.value.is<uint64_t>()) {
SQLBindParameter(_statement, 1 + binding.column, SQL_PARAM_INPUT, SQL_C_UBIGINT, SQL_INTEGER, 0, 0, &binding.value.get<uint64_t>(), 0, nullptr);
} else if(binding.value.is<double>()) {
SQLBindParameter(_statement, 1 + binding.column, SQL_PARAM_INPUT, SQL_C_DOUBLE, SQL_DOUBLE, 0, 0, &binding.value.get<double>(), 0, nullptr);
} else if(binding.value.is<string>()) {
auto& value = binding.value.get<string>();
SQLLEN length = SQL_NTS;
SQLBindParameter(_statement, 1 + binding.column, SQL_PARAM_INPUT, SQL_C_CHAR, SQL_VARCHAR, value.size(), 0, (SQLPOINTER)value.data(), 0, &length);
} else if(binding.value.is<vector<uint8_t>>()) {
auto& value = binding.value.get<vector<uint8_t>>();
SQLLEN length = value.size();
SQLBindParameter(_statement, 1 + binding.column, SQL_PARAM_INPUT, SQL_C_CHAR, SQL_VARBINARY, value.size(), 0, (SQLPOINTER)value.data(), 0, &length);
}
}
_stepped = true;
_result = SQLExecute(_statement);
if(!success()) return false;
}
_values.reset(); //clear previous row's cached read results
_result = SQLFetch(_statement);
_output = 0;
return success();
}
struct Iterator {
Iterator(Query& query, bool finished) : query(query), finished(finished) {}
auto operator*() -> Statement { return query._statement; }
auto operator!=(const Iterator& source) const -> bool { return finished != source.finished; }
auto operator++() -> Iterator& { finished = !query.step(); return *this; }
protected:
Query& query;
bool finished = false;
};
auto begin() -> Iterator { return Iterator(*this, !step()); }
auto end() -> Iterator { return Iterator(*this, true); }
private:
auto success() const -> bool {
return _result == SQL_SUCCESS || _result == SQL_SUCCESS_WITH_INFO;
}
auto statement() -> SQLHANDLE override {
if(!_stepped) step();
return _statement;
}
struct Binding {
unsigned column;
any value;
};
vector<Binding> _bindings;
SQLRETURN _result = SQL_SUCCESS;
unsigned _input = 0;
bool _stepped = false;
};
ODBC() {
_result = SQLAllocHandle(SQL_HANDLE_ENV, SQL_NULL_HANDLE, &_environment);
if(!success()) return;
SQLSetEnvAttr(_environment, SQL_ATTR_ODBC_VERSION, (void*)SQL_OV_ODBC3, 0);
}
ODBC(const string& database, const string& username, const string& password) : ODBC() {
open(database, username, password);
}
~ODBC() {
if(_environment) {
close();
SQLFreeHandle(SQL_HANDLE_ENV, _environment);
_environment = nullptr;
}
}
explicit operator bool() const { return _connection; }
auto open(const string& database, const string& username, const string& password) -> bool {
if(!_environment) return false;
close();
_result = SQLAllocHandle(SQL_HANDLE_DBC, _environment, &_connection);
if(!success()) return false;
SQLSetConnectAttr(_connection, SQL_LOGIN_TIMEOUT, (SQLPOINTER)5, 0);
_result = SQLConnectA(_connection,
(SQLCHAR*)database.data(), SQL_NTS,
(SQLCHAR*)username.data(), SQL_NTS,
(SQLCHAR*)password.data(), SQL_NTS
);
if(!success()) return close(), false;
return true;
}
auto close() -> void {
if(_connection) {
SQLDisconnect(_connection);
SQLFreeHandle(SQL_HANDLE_DBC, _connection);
_connection = nullptr;
}
}
template<typename... P> auto execute(const string& statement, P&&... p) -> Query {
if(!_connection) return {nullptr};
SQLHANDLE _statement = nullptr;
_result = SQLAllocHandle(SQL_HANDLE_STMT, _connection, &_statement);
if(!success()) return {nullptr};
Query query{_statement};
_result = SQLPrepareA(_statement, (SQLCHAR*)statement.data(), SQL_NTS);
if(!success()) return {nullptr};
bind(query, forward<P>(p)...);
return query;
}
private:
auto success() const -> bool { return _result == SQL_SUCCESS || _result == SQL_SUCCESS_WITH_INFO; }
auto bind(Query&) -> void {}
template<typename T, typename... P> auto bind(Query& query, const T& value, P&&... p) -> void {
query.bind(value);
bind(query, forward<P>(p)...);
}
SQLHANDLE _environment = nullptr;
SQLHANDLE _connection = nullptr;
SQLRETURN _result = SQL_SUCCESS;
};
}}