SQLiteQueryResult.cc

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/*
    Copyright (c) 2002-2009 Tampere University.
 
    This file is part of TTA-Based Codesign Environment (TCE).
 
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/**
 * @file SQLiteQueryResult.cc
 *
 * Implementation of SQLiteQueryResult class.
 *
 * @author Pekka Jääskeläinen 2004 (pekka.jaaskelainen-no.spam-tut.fi)
 *
 * @note rating: red
 */
 
#include <string>
using std::string;
 
#include "Application.hh"
#include "SQLiteQueryResult.hh"
#include "DataObject.hh"
#include "SQLiteConnection.hh"
 
#include "Conversion.hh"
 
/**
 * Constructor.
 *
 * @param virtualMachine Compiled SQLite virtual machine for the query.
 */
SQLiteQueryResult::SQLiteQueryResult(
    sqlite3_stmt* statement,
    SQLiteConnection* connection,
    bool init) :
    statement_(statement), 
    connection_(connection),
    dataInitialized_(init) {
 
    // initialize columnNames_ and nextData_
    if (init) {
        next();
    }
}
 
/**
 * Destructor.
 *
 * SQLite virtual machine is freed.
 *
 */
SQLiteQueryResult::~SQLiteQueryResult() {
    try {
        connection_->finalizeQuery(statement_);
    } catch (const RelationalDBException& e) {
        Application::writeToErrorLog(
            __FILE__, __LINE__, "~SQLiteQueryResult()", e.errorMessage());
    }
}
 
 
/**
 * Returns the number of columns in the result set.
 *
 * @return Number of columns, UNKNOWN_INDEX if unknown (if not supported by
 * the driver).
 */
int
SQLiteQueryResult::columns() const {
    return columnNames_.size();
}
 
/**
 * Returns the name (title) of a column in the result set.
 *
 * @param columnIndex Index of the column of which title interested.
 * @return Title. Empty string if unknown (if not supported by the driver or
 * index out of bounds).
 */
std::string
SQLiteQueryResult::columnName(std::size_t columnIndex) const {
    if (columnIndex >= columnNames_.size()) {
        return "";
    }
 
    return columnNames_[columnIndex];
}
 
/**
 * Returns the data of a column in the current row in the result set.
 *
 * @param columnIndex Index of the column of which data to return.
 * @return The data. Returns NullDataObject if the index is out of bounds.
 *
 */
const DataObject&
SQLiteQueryResult::data(std::size_t columnIndex) const {
 
    if (currentData_.size() == 0 || columnIndex >= currentData_.size()) {
        return NullDataObject::instance();
    }
    return currentData_.at(columnIndex);
}
 
/**
 * Returns the data of a column in the current row in the result set.
 *
 * This implementation is just to silence Intel compiler's warnings about
 * "partial implementation" of data() (because it's overriden function).
 *
 * @param name Name of the column of which data to return.
 * @return The data. Returns NullDataObject if the column cannot be found.
 *         Also returns NullDataObject in case the feature is not supported
 *         by the database implementation.
 *
 */
const DataObject&
SQLiteQueryResult::data(const std::string& name) const {
    return RelationalDBQueryResult::data(name);
}
 
 
/**
 * Queries if the result set contains more rows.
 *
 * @return True if there are more rows that can be accessed with next().
 */
bool
SQLiteQueryResult::hasNext() {
    if (!dataInitialized_) {
        next();
    }
    return nextData_.size() > 0;
}
 
/**
 * Advances the row cursor to next row in the result set.
 *
 * In case the current row is the last row this method does nothing but
 * returns false.
 *
 * @return True if there are still more rows to fetch.
 */
bool
SQLiteQueryResult::next() {
 
    dataInitialized_ = true;
    if (currentData_.size() > 0 && !hasNext()) {
        return false;
    }
 
    std::vector<std::string> columnNames;
 
    assert(statement_ != NULL);
 
    int columnCount = 0;
    int dataCount = 0;
 
    int result = sqlite3_step(statement_);
    columnCount = sqlite3_column_count(statement_);
    for (int i = 0; i < columnCount; i++) {
        columnNames.push_back(sqlite3_column_name(statement_, i));
    }
    currentData_ = nextData_;
    if (result == SQLITE_ROW) {
        nextData_.clear();
        dataCount = sqlite3_data_count(statement_);
        for (int i = 0; i < dataCount; i++) {
            char* columnText = (char*)sqlite3_column_text(statement_, i);
            DataObject data;
            if (columnText == NULL) {
                data.setNull();
            } else {
                data.setString(columnText);
            }
            nextData_.push_back(data);
        }
    } else if (result == SQLITE_DONE) {
        nextData_.clear();
    } else {
        // error occured
        nextData_.clear();
        return false;
    }
 
    // check if it's the initialization call when one should save column
    // names and column count
    if (columnNames_.size() == 0 && columnNames.size() != 0) {
        columnNames_ = columnNames;
    }
    return nextData_.size() > 0;
}
 
/**
 * Binds int to sqlite statement at given position (1->)
 */
void
SQLiteQueryResult::bindInt(unsigned int position, int value) {
    connection_->throwIfSQLiteError(sqlite3_bind_int(statement_, position, value));
}
 
/**
 * Binds string to sqlite statement at given position (1->)
 */
void
SQLiteQueryResult::bindString(unsigned int position, const std::string& value) {
    connection_->throwIfSQLiteError(sqlite3_bind_text(statement_, position, value.c_str(),
                -1, NULL));
}
 
/**
 * Resets compiled sqlite statement for new bindings and execution.
 */
void
SQLiteQueryResult::reset() {
    connection_->throwIfSQLiteError(sqlite3_reset(statement_));
    // reset doesn't clear bindings
    //connection_->throwIfSQLiteError(sqlite3_clear_bindings(statement_));
    columnNames_.clear();
    currentData_.clear();
    nextData_.clear();
    dataInitialized_ = false;
}