Clang: Reparse only if files are changed

Includes are now watched by a file watcher. Unsaved file changes are
watched too. If they are changed the translation units which depend on
them are set to a state which require a reparse. Later the diagnostics
of this units are collected and send back to creator.

Change-Id: I2fb5c7dd6644687f22399edd8d18edd6215c9505
Reviewed-by: Nikolai Kosjar <nikolai.kosjar@theqtcompany.com>

src/tools/clangbackend/ipcsource/clangfilesystemwatcher.cpp

@@ -0,0 +1,89 @@
+/****************************************************************************
+**
+** Copyright (C) 2015 The Qt Company Ltd.
+** Contact: http://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 http://www.qt.io/terms-conditions.  For further information
+** use the contact form at http://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 2.1 or version 3 as published by the Free
+** Software Foundation and appearing in the file LICENSE.LGPLv21 and
+** LICENSE.LGPLv3 included in the packaging of this file.  Please review the
+** following information to ensure the GNU Lesser General Public License
+** requirements will be met: https://www.gnu.org/licenses/lgpl.html and
+** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, The Qt Company gives you certain additional
+** rights.  These rights are described in The Qt Company LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+****************************************************************************/
+
+#include "clangfilesystemwatcher.h"
+
+#include "translationunits.h"
+
+#include <utf8stringvector.h>
+
+#include <QStringList>
+
+#include <algorithm>
+#include <iterator>
+
+namespace ClangBackEnd {
+
+namespace {
+QStringList toStringList(const QSet<Utf8String> &files)
+{
+    QStringList resultList;
+
+    std::copy(files.cbegin(), files.cend(), std::back_inserter(resultList));
+
+    return resultList;
+}
+}
+
+ClangFileSystemWatcher::ClangFileSystemWatcher(TranslationUnits &translationUnits)
+    : translationUnits(translationUnits)
+{
+    connect(&watcher,
+            &QFileSystemWatcher::fileChanged,
+            this,
+            &ClangFileSystemWatcher::updateTranslationUnitsWithChangedDependencies);
+
+    connect(&changedDiagnosticsTimer,
+            &QTimer::timeout,
+            this,
+            &ClangFileSystemWatcher::sendChangedDiagnostics);
+
+    changedDiagnosticsTimer.setSingleShot(true);
+    changedDiagnosticsTimer.setInterval(100);
+}
+
+void ClangFileSystemWatcher::addFiles(const QSet<Utf8String> &filePaths)
+{
+    watcher.addPaths(toStringList(filePaths));
+}
+
+void ClangFileSystemWatcher::updateTranslationUnitsWithChangedDependencies(const QString &filePath)
+{
+    translationUnits.updateTranslationUnitsWithChangedDependencies(filePath);
+    changedDiagnosticsTimer.start();
+    watcher.addPath(filePath);
+}
+
+void ClangFileSystemWatcher::sendChangedDiagnostics()
+{
+    translationUnits.sendChangedDiagnostics();
+}
+
+} // namespace ClangBackEnd