Clang: Add time stamp based filtering for project parts

The source ids are now filtered by the modified time. If the modified time
in the database is older than the modified time of the file it will be
parsed. If it is not newer it will be not parsed.

Change-Id: I4ade3443dd66573ac88053a2cafa600e54cfe973
Reviewed-by: Ivan Donchevskii <ivan.donchevskii@qt.io>

src/tools/clangrefactoringbackend/source/filestatuscache.cpp

@@ -0,0 +1,93 @@
+/****************************************************************************
+**
+** Copyright (C) 2017 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of Qt Creator.
+**
+** 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 General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3 as published by the Free Software
+** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
+** 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-3.0.html.
+**
+****************************************************************************/
+
+#include "filestatuscache.h"
+
+#include <QDateTime>
+#include <QFileInfo>
+
+namespace ClangBackEnd {
+
+FileStatusCache::FileStatusCache(FilePathCachingInterface &filePathCache)
+    : m_filePathCache(filePathCache)
+{
+
+}
+
+long long FileStatusCache::lastModifiedTime(FilePathId filePathId) const
+{
+    return findEntry(filePathId).lastModified;
+}
+
+void FileStatusCache::update(FilePathId filePathId)
+{
+    auto found = std::lower_bound(m_cacheEntries.begin(),
+                                  m_cacheEntries.end(),
+                                  Internal::FileStatusCacheEntry{filePathId},
+                                  [] (const auto &first, const auto &second) {
+        return first.filePathId < second.filePathId;
+    });
+
+    if (found != m_cacheEntries.end() && found->filePathId == filePathId) {
+        QFileInfo fileInfo = qFileInfo(filePathId);
+        found->lastModified = fileInfo.lastModified().toSecsSinceEpoch();
+    }
+}
+
+FileStatusCache::size_type FileStatusCache::size() const
+{
+    return m_cacheEntries.size();
+}
+
+Internal::FileStatusCacheEntry FileStatusCache::findEntry(FilePathId filePathId) const
+{
+    auto found = std::lower_bound(m_cacheEntries.begin(),
+                                  m_cacheEntries.end(),
+                                  Internal::FileStatusCacheEntry{filePathId},
+                                  [] (const auto &first, const auto &second) {
+        return first.filePathId < second.filePathId;
+    });
+
+    if (found != m_cacheEntries.end() && found->filePathId == filePathId)
+        return *found;
+
+    QFileInfo fileInfo = qFileInfo(filePathId);
+    auto inserted = m_cacheEntries.emplace(found,
+                                           filePathId,
+                                           fileInfo.lastModified().toSecsSinceEpoch());
+
+    return *inserted;
+}
+
+QFileInfo FileStatusCache::qFileInfo(FilePathId filePathId) const
+{
+    QFileInfo fileInfo(QString(m_filePathCache.filePath(filePathId)));
+
+    fileInfo.refresh();
+
+    return fileInfo;
+}
+
+} // namespace ClangBackEnd