Separate header verification and mmap handling of CompiledData::Unit

...into a separate class. This will make it easier to specialize the
handling for Posix and Windows platforms.

Change-Id: I995538fa8239eac8586c96812086e50b4c19257f
Reviewed-by: Lars Knoll <lars.knoll@qt.io>

1 files changed, 114 insertions, 0 deletions

diff --git a/src/qml/compiler/qv4compilationunitmapper.cpp b/src/qml/compiler/qv4compilationunitmapper.cpp
new file mode 100644
index 0000000000..1d8be036c9
--- /dev/null
+++ b/src/qml/compiler/qv4compilationunitmapper.cpp
@@ -0,0 +1,114 @@
+/****************************************************************************
+**
+** Copyright (C) 2016 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the QtQml module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL3 included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 2.0 or (at your option) the GNU General
+** Public license version 3 or any later version approved by the KDE Free
+** Qt Foundation. The licenses are as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-2.0.html and
+** https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "qv4compilationunitmapper_p.h"
+
+#include "qv4compileddata_p.h"
+#include <QFileInfo>
+#include <QDateTime>
+
+QT_BEGIN_NAMESPACE
+
+using namespace QV4;
+
+CompilationUnitMapper::CompilationUnitMapper()
+    : dataPtr(nullptr)
+{
+
+}
+
+CompiledData::Unit *CompilationUnitMapper::open(const QString &sourcePath, QString *errorString)
+{
+    close();
+
+    f.setFileName(sourcePath + QLatin1Char('c'));
+    if (!f.open(QIODevice::ReadOnly)) {
+        *errorString = f.errorString();
+        return nullptr;
+    }
+
+    CompiledData::Unit header;
+    qint64 bytesRead = f.read(reinterpret_cast<char *>(&header), sizeof(header));
+
+    if (bytesRead != sizeof(header)) {
+        *errorString = QStringLiteral("File too small for the header fields");
+        return nullptr;
+    }
+
+    if (strncmp(header.magic, CompiledData::magic_str, sizeof(header.magic))) {
+        *errorString = QStringLiteral("Magic bytes in the header do not match");
+        return nullptr;
+    }
+
+    if (header.version != quint32(QV4_DATA_STRUCTURE_VERSION)) {
+        *errorString = QString::fromUtf8("V4 data structure version mismatch. Found %1 expected %2").arg(header.version, 0, 16).arg(QV4_DATA_STRUCTURE_VERSION, 0, 16);
+        return nullptr;
+    }
+
+    if (header.qtVersion != quint32(QT_VERSION)) {
+        *errorString = QString::fromUtf8("Qt version mismatch. Found %1 expected %2").arg(header.qtVersion, 0, 16).arg(QT_VERSION, 0, 16);
+        return nullptr;
+    }
+
+    {
+        QFileInfo sourceCode(sourcePath);
+        if (sourceCode.exists() && sourceCode.lastModified().toMSecsSinceEpoch() != header.sourceTimeStamp) {
+            *errorString = QStringLiteral("QML source file has a different time stamp than cached file.");
+            return nullptr;
+        }
+    }
+
+    // Data structure and qt version matched, so now we can access the rest of the file safely.
+
+    dataPtr = f.map(/*offset*/0, f.size());
+    if (!dataPtr) {
+        *errorString = f.errorString();
+        return nullptr;
+    }
+
+    return reinterpret_cast<CompiledData::Unit*>(dataPtr);
+}
+
+void CompilationUnitMapper::close()
+{
+    f.close();
+    dataPtr = nullptr;
+}
+
+QT_END_NAMESPACE