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      1 /*
      2  * Copyright (C) 2007, 2013 Apple Inc. All rights reserved.
      3  *
      4  * Redistribution and use in source and binary forms, with or without
      5  * modification, are permitted provided that the following conditions
      6  * are met:
      7  *
      8  * 1.  Redistributions of source code must retain the above copyright
      9  *     notice, this list of conditions and the following disclaimer.
     10  * 2.  Redistributions in binary form must reproduce the above copyright
     11  *     notice, this list of conditions and the following disclaimer in the
     12  *     documentation and/or other materials provided with the distribution.
     13  * 3.  Neither the name of Apple Computer, Inc. ("Apple") nor the names of
     14  *     its contributors may be used to endorse or promote products derived
     15  *     from this software without specific prior written permission.
     16  *
     17  * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
     18  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
     19  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
     20  * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
     21  * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
     22  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
     23  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
     24  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
     26  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     27  */
     28 #include "config.h"
     29 #include "modules/webdatabase/SQLStatementBackend.h"
     30 
     31 #include "modules/webdatabase/Database.h"
     32 #include "modules/webdatabase/SQLError.h"
     33 #include "modules/webdatabase/SQLStatement.h"
     34 #include "modules/webdatabase/sqlite/SQLiteDatabase.h"
     35 #include "modules/webdatabase/sqlite/SQLiteStatement.h"
     36 #include "platform/Logging.h"
     37 #include "wtf/text/CString.h"
     38 
     39 
     40 // The Life-Cycle of a SQLStatement i.e. Who's keeping the SQLStatement alive?
     41 // ==========================================================================
     42 // The RefPtr chain goes something like this:
     43 //
     44 //     At birth (in SQLTransactionBackend::executeSQL()):
     45 //     =================================================
     46 //     SQLTransactionBackend           // Deque<RefPtr<SQLStatementBackend> > m_statementQueue points to ...
     47 //     --> SQLStatementBackend         // OwnPtr<SQLStatement> m_frontend points to ...
     48 //         --> SQLStatement
     49 //
     50 //     After grabbing the statement for execution (in SQLTransactionBackend::getNextStatement()):
     51 //     =========================================================================================
     52 //     SQLTransactionBackend           // RefPtr<SQLStatementBackend> m_currentStatementBackend points to ...
     53 //     --> SQLStatementBackend         // OwnPtr<SQLStatement> m_frontend points to ...
     54 //         --> SQLStatement
     55 //
     56 //     Then we execute the statement in SQLTransactionBackend::runCurrentStatementAndGetNextState().
     57 //     And we callback to the script in SQLTransaction::deliverStatementCallback() if
     58 //     necessary.
     59 //     - Inside SQLTransaction::deliverStatementCallback(), we operate on a raw SQLStatement*.
     60 //       This pointer is valid because it is owned by SQLTransactionBackend's
     61 //       SQLTransactionBackend::m_currentStatementBackend.
     62 //
     63 //     After we're done executing the statement (in SQLTransactionBackend::getNextStatement()):
     64 //     =======================================================================================
     65 //     When we're done executing, we'll grab the next statement. But before we
     66 //     do that, getNextStatement() nullify SQLTransactionBackend::m_currentStatementBackend.
     67 //     This will trigger the deletion of the SQLStatementBackend and SQLStatement.
     68 //
     69 //     Note: unlike with SQLTransaction, there is no JS representation of SQLStatement.
     70 //     Hence, there is no GC dependency at play here.
     71 
     72 namespace blink {
     73 
     74 PassRefPtrWillBeRawPtr<SQLStatementBackend> SQLStatementBackend::create(PassOwnPtrWillBeRawPtr<SQLStatement> frontend,
     75     const String& statement, const Vector<SQLValue>& arguments, int permissions)
     76 {
     77     return adoptRefWillBeNoop(new SQLStatementBackend(frontend, statement, arguments, permissions));
     78 }
     79 
     80 SQLStatementBackend::SQLStatementBackend(PassOwnPtrWillBeRawPtr<SQLStatement> frontend,
     81     const String& statement, const Vector<SQLValue>& arguments, int permissions)
     82     : m_frontend(frontend)
     83     , m_statement(statement.isolatedCopy())
     84     , m_arguments(arguments)
     85     , m_hasCallback(m_frontend->hasCallback())
     86     , m_hasErrorCallback(m_frontend->hasErrorCallback())
     87     , m_resultSet(SQLResultSet::create())
     88     , m_permissions(permissions)
     89 {
     90     m_frontend->setBackend(this);
     91 }
     92 
     93 void SQLStatementBackend::trace(Visitor* visitor)
     94 {
     95     visitor->trace(m_frontend);
     96     visitor->trace(m_resultSet);
     97 }
     98 
     99 SQLStatement* SQLStatementBackend::frontend()
    100 {
    101     return m_frontend.get();
    102 }
    103 
    104 SQLErrorData* SQLStatementBackend::sqlError() const
    105 {
    106     return m_error.get();
    107 }
    108 
    109 SQLResultSet* SQLStatementBackend::sqlResultSet() const
    110 {
    111     return m_resultSet->isValid() ? m_resultSet.get() : 0;
    112 }
    113 
    114 bool SQLStatementBackend::execute(Database* db)
    115 {
    116     ASSERT(!m_resultSet->isValid());
    117 
    118     // If we're re-running this statement after a quota violation, we need to clear that error now
    119     clearFailureDueToQuota();
    120 
    121     // This transaction might have been marked bad while it was being set up on the main thread,
    122     // so if there is still an error, return false.
    123     if (m_error)
    124         return false;
    125 
    126     db->setAuthorizerPermissions(m_permissions);
    127 
    128     SQLiteDatabase* database = &db->sqliteDatabase();
    129 
    130     SQLiteStatement statement(*database, m_statement);
    131     int result = statement.prepare();
    132 
    133     if (result != SQLResultOk) {
    134         WTF_LOG(StorageAPI, "Unable to verify correctness of statement %s - error %i (%s)", m_statement.ascii().data(), result, database->lastErrorMsg());
    135         if (result == SQLResultInterrupt)
    136             m_error = SQLErrorData::create(SQLError::DATABASE_ERR, "could not prepare statement", result, "interrupted");
    137         else
    138             m_error = SQLErrorData::create(SQLError::SYNTAX_ERR, "could not prepare statement", result, database->lastErrorMsg());
    139         db->reportExecuteStatementResult(1, m_error->code(), result);
    140         return false;
    141     }
    142 
    143     // FIXME: If the statement uses the ?### syntax supported by sqlite, the bind parameter count is very likely off from the number of question marks.
    144     // If this is the case, they might be trying to do something fishy or malicious
    145     if (statement.bindParameterCount() != m_arguments.size()) {
    146         WTF_LOG(StorageAPI, "Bind parameter count doesn't match number of question marks");
    147         m_error = SQLErrorData::create(SQLError::SYNTAX_ERR, "number of '?'s in statement string does not match argument count");
    148         db->reportExecuteStatementResult(2, m_error->code(), 0);
    149         return false;
    150     }
    151 
    152     for (unsigned i = 0; i < m_arguments.size(); ++i) {
    153         result = statement.bindValue(i + 1, m_arguments[i]);
    154         if (result == SQLResultFull) {
    155             setFailureDueToQuota(db);
    156             return false;
    157         }
    158 
    159         if (result != SQLResultOk) {
    160             WTF_LOG(StorageAPI, "Failed to bind value index %i to statement for query '%s'", i + 1, m_statement.ascii().data());
    161             db->reportExecuteStatementResult(3, SQLError::DATABASE_ERR, result);
    162             m_error = SQLErrorData::create(SQLError::DATABASE_ERR, "could not bind value", result, database->lastErrorMsg());
    163             return false;
    164         }
    165     }
    166 
    167     // Step so we can fetch the column names.
    168     result = statement.step();
    169     if (result == SQLResultRow) {
    170         int columnCount = statement.columnCount();
    171         SQLResultSetRowList* rows = m_resultSet->rows();
    172 
    173         for (int i = 0; i < columnCount; i++)
    174             rows->addColumn(statement.getColumnName(i));
    175 
    176         do {
    177             for (int i = 0; i < columnCount; i++)
    178                 rows->addResult(statement.getColumnValue(i));
    179 
    180             result = statement.step();
    181         } while (result == SQLResultRow);
    182 
    183         if (result != SQLResultDone) {
    184             db->reportExecuteStatementResult(4, SQLError::DATABASE_ERR, result);
    185             m_error = SQLErrorData::create(SQLError::DATABASE_ERR, "could not iterate results", result, database->lastErrorMsg());
    186             return false;
    187         }
    188     } else if (result == SQLResultDone) {
    189         // Didn't find anything, or was an insert
    190         if (db->lastActionWasInsert())
    191             m_resultSet->setInsertId(database->lastInsertRowID());
    192     } else if (result == SQLResultFull) {
    193         // Return the Quota error - the delegate will be asked for more space and this statement might be re-run
    194         setFailureDueToQuota(db);
    195         return false;
    196     } else if (result == SQLResultConstraint) {
    197         db->reportExecuteStatementResult(6, SQLError::CONSTRAINT_ERR, result);
    198         m_error = SQLErrorData::create(SQLError::CONSTRAINT_ERR, "could not execute statement due to a constaint failure", result, database->lastErrorMsg());
    199         return false;
    200     } else {
    201         db->reportExecuteStatementResult(5, SQLError::DATABASE_ERR, result);
    202         m_error = SQLErrorData::create(SQLError::DATABASE_ERR, "could not execute statement", result, database->lastErrorMsg());
    203         return false;
    204     }
    205 
    206     // FIXME: If the spec allows triggers, and we want to be "accurate" in a different way, we'd use
    207     // sqlite3_total_changes() here instead of sqlite3_changed, because that includes rows modified from within a trigger
    208     // For now, this seems sufficient
    209     m_resultSet->setRowsAffected(database->lastChanges());
    210 
    211     db->reportExecuteStatementResult(0, -1, 0); // OK
    212     return true;
    213 }
    214 
    215 void SQLStatementBackend::setVersionMismatchedError(Database* database)
    216 {
    217     ASSERT(!m_error && !m_resultSet->isValid());
    218     database->reportExecuteStatementResult(7, SQLError::VERSION_ERR, 0);
    219     m_error = SQLErrorData::create(SQLError::VERSION_ERR, "current version of the database and `oldVersion` argument do not match");
    220 }
    221 
    222 void SQLStatementBackend::setFailureDueToQuota(Database* database)
    223 {
    224     ASSERT(!m_error && !m_resultSet->isValid());
    225     database->reportExecuteStatementResult(8, SQLError::QUOTA_ERR, 0);
    226     m_error = SQLErrorData::create(SQLError::QUOTA_ERR, "there was not enough remaining storage space, or the storage quota was reached and the user declined to allow more space");
    227 }
    228 
    229 void SQLStatementBackend::clearFailureDueToQuota()
    230 {
    231     if (lastExecutionFailedDueToQuota())
    232         m_error = nullptr;
    233 }
    234 
    235 bool SQLStatementBackend::lastExecutionFailedDueToQuota() const
    236 {
    237     return m_error && m_error->code() == SQLError::QUOTA_ERR;
    238 }
    239 
    240 } // namespace blink
    241