ThreadPooler to replace ThreadWeaver

Initial version of ThreadPooler to substitute 3rd party ThreadWeaver.
Qt3D will be released under LGPLv3 and commercial licensing terms,
therefore we can't share code with free licenses.

Change-Id: Ic0956b40e4960002205ee32c19a053813339791c
Reviewed-by: Sean Harmer <sean.harmer@kdab.com>

1 files changed, 127 insertions, 0 deletions

diff --git a/src/core/jobs/dependencyhandler.cpp b/src/core/jobs/dependencyhandler.cpp
new file mode 100644
index 000000000..9778ede58
--- /dev/null
+++ b/src/core/jobs/dependencyhandler.cpp
@@ -0,0 +1,127 @@
+/****************************************************************************
+**
+** Copyright (C) 2015 The Qt Company Ltd.
+** Contact: http://www.qt.io/licensing/
+**
+** This file is part of the Qt3D module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL3$
+** 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 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPLv3 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.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 later as published by the Free
+** Software Foundation and appearing in the file LICENSE.GPL included in
+** the packaging of this file. Please review the following information to
+** ensure the GNU General Public License version 2.0 requirements will be
+** met: http://www.gnu.org/licenses/gpl-2.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include <iterator>
+
+#include "dependencyhandler_p.h"
+
+QT_BEGIN_NAMESPACE
+
+namespace Qt3D {
+
+namespace {
+    template <template <typename T> class Op>
+    struct ByDepender {
+        typedef bool result_type;
+
+        bool operator()(const QSharedPointer<TaskInterface> &lhs, const QSharedPointer<TaskInterface> &rhs) const Q_DECL_NOTHROW
+        { return Op<QSharedPointer<TaskInterface> >()(lhs, rhs); }
+
+        bool operator()(const QSharedPointer<TaskInterface> &lhs, const Dependency &rhs) const Q_DECL_NOTHROW
+        { return operator()(lhs, rhs.depender); }
+
+        bool operator()(const Dependency &lhs, const QSharedPointer<TaskInterface> &rhs) const Q_DECL_NOTHROW
+        { return operator()(lhs.depender, rhs); }
+
+        bool operator()(const Dependency &lhs, const Dependency &rhs) const Q_DECL_NOTHROW
+        { return operator()(lhs.depender, rhs.depender); }
+    };
+
+    struct DependeeEquals : std::unary_function<Dependency, bool>
+    {
+        QSharedPointer<TaskInterface> dependee;
+        explicit DependeeEquals(QSharedPointer<TaskInterface> dependee)
+            : dependee(qMove(dependee)) {}
+        bool operator()(const Dependency &candidate) const
+        {
+            return dependee == candidate.dependee;
+        }
+    };
+
+    struct ByDependerThenDependee : std::binary_function<Dependency, Dependency, bool>
+    {
+        // Defines a lexicographical order (depender first).
+        bool operator()(const Dependency &lhs, const Dependency &rhs)
+        {
+            if (lhs.depender < rhs.depender) return true;
+            if (rhs.depender < lhs.depender) return false;
+            return lhs.dependee < rhs.dependee;
+        }
+    };
+}
+
+DependencyHandler::DependencyHandler()
+{
+}
+
+void DependencyHandler::addDependencies(QVector<Dependency> dependencies)
+{
+    std::sort(dependencies.begin(), dependencies.end(), ByDependerThenDependee());
+
+    const QMutexLocker locker(&m_mutex);
+
+    QVector<Dependency> newDependencyMap;
+    newDependencyMap.reserve(dependencies.size() + m_dependencyMap.size());
+    std::set_union(m_dependencyMap.begin(), m_dependencyMap.end(),
+                   dependencies.begin(), dependencies.end(),
+                   std::back_inserter(newDependencyMap), ByDependerThenDependee());
+    m_dependencyMap.swap(newDependencyMap); // commit
+}
+
+bool DependencyHandler::hasDependency(const QSharedPointer<TaskInterface> &depender)
+{
+    const QMutexLocker locker(&m_mutex);
+
+    return std::binary_search(m_dependencyMap.begin(), m_dependencyMap.end(),
+                              depender, ByDepender<std::less>());
+}
+
+/*
+ * Removes all the entries on the m_dependencyMap that have given task as a dependee,
+ * i.e. entries where the dependency is on the given task.
+ */
+void DependencyHandler::freeDependencies(const QSharedPointer<TaskInterface> &dependee)
+{
+    const QMutexLocker locker(&m_mutex);
+
+    m_dependencyMap.erase(std::remove_if(m_dependencyMap.begin(), m_dependencyMap.end(),
+                                         DependeeEquals(dependee)),
+                          m_dependencyMap.end());
+}
+
+} // namespace Qt3D
+
+QT_END_NAMESPACE