root/Source/modules/webdatabase/sqlite/SQLiteStatement.cpp

DEFINITIONS

1. m_isPrepared
2. prepare
3. step
4. finalize
5. executeCommand
6. bindText
7. bindDouble
8. bindNull
9. bindValue
10. bindParameterCount
11. columnCount
12. getColumnName
13. getColumnValue
14. getColumnText
15. getColumnInt
16. getColumnInt64

/*
 * Copyright (C) 2006, 2007, 2008 Apple Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include "config.h"
#include "modules/webdatabase/sqlite/SQLiteStatement.h"

#include <sqlite3.h>
#include "platform/Logging.h"
#include "modules/webdatabase/sqlite/SQLValue.h"
#include "wtf/Assertions.h"
#include "wtf/text/CString.h"

// SQLite 3.6.16 makes sqlite3_prepare_v2 automatically retry preparing the statement
// once if the database scheme has changed. We rely on this behavior.
#if SQLITE_VERSION_NUMBER < 3006016
#error SQLite version 3.6.16 or newer is required
#endif

namespace WebCore {

SQLiteStatement::SQLiteStatement(SQLiteDatabase& db, const String& sql)
    : m_database(db)
    , m_query(sql)
    , m_statement(0)
#ifndef NDEBUG
    , m_isPrepared(false)
#endif
{
}

SQLiteStatement::~SQLiteStatement()
{
    finalize();
}

int SQLiteStatement::prepare()
{
    ASSERT(!m_isPrepared);

    MutexLocker databaseLock(m_database.databaseMutex());
    if (m_database.isInterrupted())
        return SQLITE_INTERRUPT;

    CString query = m_query.stripWhiteSpace().utf8();

    WTF_LOG(SQLDatabase, "SQL - prepare - %s", query.data());

    // Pass the length of the string including the null character to sqlite3_prepare_v2;
    // this lets SQLite avoid an extra string copy.
    size_t lengthIncludingNullCharacter = query.length() + 1;

    const char* tail;
    int error = sqlite3_prepare_v2(m_database.sqlite3Handle(), query.data(), lengthIncludingNullCharacter, &m_statement, &tail);

    if (error != SQLITE_OK)
        WTF_LOG(SQLDatabase, "sqlite3_prepare16 failed (%i)\n%s\n%s", error, query.data(), sqlite3_errmsg(m_database.sqlite3Handle()));

    if (tail && *tail)
        error = SQLITE_ERROR;

#ifndef NDEBUG
    m_isPrepared = error == SQLITE_OK;
#endif
    return error;
}

int SQLiteStatement::step()
{
    MutexLocker databaseLock(m_database.databaseMutex());
    if (m_database.isInterrupted())
        return SQLITE_INTERRUPT;
    //ASSERT(m_isPrepared);

    if (!m_statement)
        return SQLITE_OK;

    // The database needs to update its last changes count before each statement
    // in order to compute properly the lastChanges() return value.
    m_database.updateLastChangesCount();

    WTF_LOG(SQLDatabase, "SQL - step - %s", m_query.ascii().data());
    int error = sqlite3_step(m_statement);
    if (error != SQLITE_DONE && error != SQLITE_ROW) {
        WTF_LOG(SQLDatabase, "sqlite3_step failed (%i)\nQuery - %s\nError - %s",
            error, m_query.ascii().data(), sqlite3_errmsg(m_database.sqlite3Handle()));
    }

    return error;
}

int SQLiteStatement::finalize()
{
#ifndef NDEBUG
    m_isPrepared = false;
#endif
    if (!m_statement)
        return SQLITE_OK;
    WTF_LOG(SQLDatabase, "SQL - finalize - %s", m_query.ascii().data());
    int result = sqlite3_finalize(m_statement);
    m_statement = 0;
    return result;
}

bool SQLiteStatement::executeCommand()
{
    if (!m_statement && prepare() != SQLITE_OK)
        return false;
    ASSERT(m_isPrepared);
    if (step() != SQLITE_DONE) {
        finalize();
        return false;
    }
    finalize();
    return true;
}

int SQLiteStatement::bindText(int index, const String& text)
{
    ASSERT(m_isPrepared);
    ASSERT(index > 0);
    ASSERT(static_cast<unsigned>(index) <= bindParameterCount());

    // SQLite treats uses zero pointers to represent null strings, which means we need to make sure to map null WTFStrings to zero pointers.
    ASSERT(!String().charactersWithNullTermination().data());
    return sqlite3_bind_text16(m_statement, index, text.charactersWithNullTermination().data(), sizeof(UChar) * text.length(), SQLITE_TRANSIENT);
}

int SQLiteStatement::bindDouble(int index, double number)
{
    ASSERT(m_isPrepared);
    ASSERT(index > 0);
    ASSERT(static_cast<unsigned>(index) <= bindParameterCount());

    return sqlite3_bind_double(m_statement, index, number);
}

int SQLiteStatement::bindNull(int index)
{
    ASSERT(m_isPrepared);
    ASSERT(index > 0);
    ASSERT(static_cast<unsigned>(index) <= bindParameterCount());

    return sqlite3_bind_null(m_statement, index);
}

int SQLiteStatement::bindValue(int index, const SQLValue& value)
{
    switch (value.type()) {
        case SQLValue::StringValue:
            return bindText(index, value.string());
        case SQLValue::NumberValue:
            return bindDouble(index, value.number());
        case SQLValue::NullValue:
            return bindNull(index);
    }

    ASSERT_NOT_REACHED();
    return SQLITE_ERROR;
}

unsigned SQLiteStatement::bindParameterCount() const
{
    ASSERT(m_isPrepared);
    if (!m_statement)
        return 0;
    return sqlite3_bind_parameter_count(m_statement);
}

int SQLiteStatement::columnCount()
{
    ASSERT(m_isPrepared);
    if (!m_statement)
        return 0;
    return sqlite3_data_count(m_statement);
}

String SQLiteStatement::getColumnName(int col)
{
    ASSERT(col >= 0);
    if (!m_statement)
        if (prepareAndStep() != SQLITE_ROW)
            return String();
    if (columnCount() <= col)
        return String();
    return String(reinterpret_cast<const UChar*>(sqlite3_column_name16(m_statement, col)));
}

SQLValue SQLiteStatement::getColumnValue(int col)
{
    ASSERT(col >= 0);
    if (!m_statement)
        if (prepareAndStep() != SQLITE_ROW)
            return SQLValue();
    if (columnCount() <= col)
        return SQLValue();

    // SQLite is typed per value. optional column types are
    // "(mostly) ignored"
    sqlite3_value* value = sqlite3_column_value(m_statement, col);
    switch (sqlite3_value_type(value)) {
        case SQLITE_INTEGER:    // SQLValue and JS don't represent integers, so use FLOAT -case
        case SQLITE_FLOAT:
            return SQLValue(sqlite3_value_double(value));
        case SQLITE_BLOB:       // SQLValue and JS don't represent blobs, so use TEXT -case
        case SQLITE_TEXT: {
            const UChar* string = reinterpret_cast<const UChar*>(sqlite3_value_text16(value));
            unsigned length = WTF::lengthOfNullTerminatedString(string);
            return SQLValue(StringImpl::create8BitIfPossible(string, length));
        }
        case SQLITE_NULL:
            return SQLValue();
        default:
            break;
    }
    ASSERT_NOT_REACHED();
    return SQLValue();
}

String SQLiteStatement::getColumnText(int col)
{
    ASSERT(col >= 0);
    if (!m_statement)
        if (prepareAndStep() != SQLITE_ROW)
            return String();
    if (columnCount() <= col)
        return String();
    const UChar* string = reinterpret_cast<const UChar*>(sqlite3_column_text16(m_statement, col));
    return StringImpl::create8BitIfPossible(string, sqlite3_column_bytes16(m_statement, col) / sizeof(UChar));
}

int SQLiteStatement::getColumnInt(int col)
{
    ASSERT(col >= 0);
    if (!m_statement)
        if (prepareAndStep() != SQLITE_ROW)
            return 0;
    if (columnCount() <= col)
        return 0;
    return sqlite3_column_int(m_statement, col);
}

int64_t SQLiteStatement::getColumnInt64(int col)
{
    ASSERT(col >= 0);
    if (!m_statement)
        if (prepareAndStep() != SQLITE_ROW)
            return 0;
    if (columnCount() <= col)
        return 0;
    return sqlite3_column_int64(m_statement, col);
}

} // namespace WebCore