poco/Data/SQLite/src/SQLiteStatementImpl.cpp

//
// SQLiteStatementImpl.cpp
//
// $Id: //poco/Main/Data/SQLite/src/SQLiteStatementImpl.cpp#8 $
//
// Library: SQLite
// Package: SQLite
// Module:  SQLiteStatementImpl
//
// Copyright (c) 2006, Applied Informatics Software Engineering GmbH.
// and Contributors.
//
// Permission is hereby granted, free of charge, to any person or organization
// obtaining a copy of the software and accompanying documentation covered by
// this license (the "Software") to use, reproduce, display, distribute,
// execute, and transmit the Software, and to prepare derivative works of the
// Software, and to permit third-parties to whom the Software is furnished to
// do so, all subject to the following:
// 
// The copyright notices in the Software and this entire statement, including
// the above license grant, this restriction and the following disclaimer,
// must be included in all copies of the Software, in whole or in part, and
// all derivative works of the Software, unless such copies or derivative
// works are solely in the form of machine-executable object code generated by
// a source language processor.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
// SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
// FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
// ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
// DEALINGS IN THE SOFTWARE.
//


#include "Poco/Data/SQLite/SQLiteStatementImpl.h"
#include "Poco/Data/SQLite/Utility.h"
#include "Poco/Data/SQLite/SQLiteException.h"
#include "Poco/String.h"
#include <cstdlib>
#include <cstring>
#include "sqlite3.h"


namespace Poco {
namespace Data {
namespace SQLite {


SQLiteStatementImpl::SQLiteStatementImpl(Poco::Data::SessionImpl& rSession, sqlite3* pDB):
	StatementImpl(rSession),
	_pDB(pDB),
	_pStmt(0),
	_stepCalled(false),
	_nextResponse(0),
	_affectedRowCount(0),
	_canBind(false),
	_isExtracted(false)
{
	_columns.resize(1);
}


SQLiteStatementImpl::~SQLiteStatementImpl()
{
	clear();
}


bool SQLiteStatementImpl::compileImpl()
{
	if (_pLeftover && _pLeftover->empty()) 
	{
		_pLeftover = 0;
		return false;
	}
	else if (!_pLeftover)
		_bindBegin = bindings().begin();

	std::string statement(toString());
	sqlite3_stmt* pStmt = 0;
	const char* pSql = _pLeftover ? _pLeftover->c_str() : statement.c_str();

	if (0 == std::strlen(pSql))
		throw InvalidSQLStatementException("Empty statements are illegal");

	int rc = SQLITE_OK;
	const char* pLeftover = 0;
	bool queryFound = false;

	do
	{
		rc = sqlite3_prepare_v2(_pDB, pSql, -1, &pStmt, &pLeftover);
		if (rc != SQLITE_OK)
		{
			if (pStmt) sqlite3_finalize(pStmt);
			pStmt = 0;
			std::string errMsg = sqlite3_errmsg(_pDB);
			Utility::throwException(rc, errMsg);
		}
		else if (rc == SQLITE_OK && pStmt)
		{
			queryFound = true;
		}
		else if(rc == SQLITE_OK && !pStmt) // comment/whitespace ignore
		{
			pSql = pLeftover;
			if (std::strlen(pSql) == 0)
			{
				// empty statement or an conditional statement! like CREATE IF NOT EXISTS
				// this is valid
				queryFound = true;
			}
		}
	} while (rc == SQLITE_OK && !pStmt && !queryFound);

	//Finalization call in clear() invalidates the pointer, so the value is remembered here.
	//For last statement in a batch (or a single statement), pLeftover == "", so the next call
	// to compileImpl() shall return false immediately when there are no more statements left.
	std::string leftOver(pLeftover);
	clear();
	_pStmt = pStmt;
	_pLeftover = new std::string(leftOver);
	trimInPlace(*_pLeftover);

	_pBinder = new Binder(_pStmt);
	_pExtractor = new Extractor(_pStmt);

	if (SQLITE_DONE == _nextResponse && _isExtracted)
	{
		//if this is not the first compile and there has already been extraction
		//during previous step, switch to the next set if there is one provided
		if (hasMoreDataSets())
		{
			activateNextDataSet();
			_isExtracted = false;
		}
	}

	int colCount = sqlite3_column_count(_pStmt);

	if (colCount)
	{
		Poco::UInt32 curDataSet = currentDataSet();
		if (curDataSet >= _columns.size()) _columns.resize(curDataSet + 1);
		for (int i = 0; i < colCount; ++i)
		{
			MetaColumn mc(i, sqlite3_column_name(_pStmt, i), Utility::getColumnType(_pStmt, i));
			_columns[curDataSet].push_back(mc);
		}
	}

	return true;
}


void SQLiteStatementImpl::bindImpl()
{
	_stepCalled = false;
	_nextResponse = 0;
	if (_pStmt == 0) return;

	sqlite3_reset(_pStmt);

	int paramCount = sqlite3_bind_parameter_count(_pStmt);
	BindIt bindEnd = bindings().end();
	if (0 == paramCount || bindEnd == _bindBegin) 
	{
		_canBind = false;
		return;
	}

	int availableCount = 0;
	Bindings::difference_type bindCount = 0;
	Bindings::iterator it = _bindBegin;
	for (; it != bindEnd; ++it)
	{
		availableCount += (*it)->numOfColumnsHandled();
		if (availableCount <= paramCount) ++bindCount;
		else break;
	}

	Bindings::difference_type remainingBindCount = bindEnd - _bindBegin;
	if (bindCount < remainingBindCount)
	{
		bindEnd = _bindBegin + bindCount;
		_canBind = true;
	}
	else if (bindCount > remainingBindCount)
		throw ParameterCountMismatchException();

	if (_bindBegin != bindings().end())
	{
		_affectedRowCount = (*_bindBegin)->numOfRowsHandled();

		Bindings::iterator oldBegin = _bindBegin;
		for (std::size_t pos = 1; _bindBegin != bindEnd && (*_bindBegin)->canBind(); ++_bindBegin)
		{
			if (_affectedRowCount != (*_bindBegin)->numOfRowsHandled())
				throw BindingException("Size mismatch in Bindings. All Bindings MUST have the same size");

			(*_bindBegin)->bind(pos);
			pos += (*_bindBegin)->numOfColumnsHandled();
		}

		if ((*oldBegin)->canBind())
		{
			//container binding will come back for more, so we must rewind
			_bindBegin = oldBegin;
			_canBind = true;
		}
		else _canBind = false;
	}
}


void SQLiteStatementImpl::clear()
{
	_columns[currentDataSet()].clear();
	_affectedRowCount = 0;

	if (_pStmt)
	{
		sqlite3_finalize(_pStmt);
		_pStmt=0;
	}
	_pLeftover = 0;
	_canBind = false;
}


bool SQLiteStatementImpl::hasNext()
{
	if (_stepCalled)
		return (_nextResponse == SQLITE_ROW);

	// _pStmt is allowed to be null for conditional SQL statements
	if (_pStmt == 0)
	{
		_stepCalled   = true;
		_nextResponse = SQLITE_DONE;
		return false;
	}

	_stepCalled   = true;
	_nextResponse = sqlite3_step(_pStmt);

	if (_nextResponse != SQLITE_ROW && _nextResponse != SQLITE_OK && _nextResponse != SQLITE_DONE)
		Utility::throwException(_nextResponse);

	_pExtractor->reset();//clear the cached null indicators

	return (_nextResponse == SQLITE_ROW);
}


Poco::UInt32 SQLiteStatementImpl::next()
{
	if (SQLITE_ROW == _nextResponse)
	{
		poco_assert (columnsReturned() == sqlite3_column_count(_pStmt));

		Extractions& extracts = extractions();
		Extractions::iterator it = extracts.begin();
		Extractions::iterator itEnd = extracts.end();
		std::size_t pos = 0; // sqlite starts with pos 0 for results!
		for (; it != itEnd; ++it)
		{
			(*it)->extract(pos);
			pos += (*it)->numOfColumnsHandled();
			_isExtracted = true;
		}
		_stepCalled = false;
	}
	else if (SQLITE_DONE == _nextResponse)
	{
		throw Poco::Data::DataException("No data received");
	}
	else
	{
		int rc = _nextResponse;
		Utility::throwException(rc, std::string("Iterator Error: trying to access the next value"));
	}
	
	return 1u;
}


Poco::UInt32 SQLiteStatementImpl::columnsReturned() const
{
	return (Poco::UInt32) _columns[currentDataSet()].size();
}


const MetaColumn& SQLiteStatementImpl::metaColumn(Poco::UInt32 pos) const
{
	Poco::UInt32 curDataSet = currentDataSet();
	poco_assert (pos >= 0 && pos <= _columns[curDataSet].size());
	return _columns[curDataSet][pos];
}


Poco::UInt32 SQLiteStatementImpl::affectedRowCount() const
{
	return _affectedRowCount ? _affectedRowCount : sqlite3_changes(_pDB);
}


} } } // namespace Poco::Data::SQLite