From 3557eacbd05d9c3fe28f53e00e6d5ebf41102999 Mon Sep 17 00:00:00 2001
From: Atlante45 <clement.brisset@gmail.com>
Date: Tue, 10 Nov 2015 18:18:29 -0800
Subject: [PATCH] Add QTryRead/WriteLocker classes

---
 libraries/shared/src/shared/QTryReadLocker.h  | 92 +++++++++++++++++++
 libraries/shared/src/shared/QTryWriteLocker.h | 92 +++++++++++++++++++
 2 files changed, 184 insertions(+)
 create mode 100644 libraries/shared/src/shared/QTryReadLocker.h
 create mode 100644 libraries/shared/src/shared/QTryWriteLocker.h

diff --git a/libraries/shared/src/shared/QTryReadLocker.h b/libraries/shared/src/shared/QTryReadLocker.h
new file mode 100644
index 0000000000..573eba61b8
--- /dev/null
+++ b/libraries/shared/src/shared/QTryReadLocker.h
@@ -0,0 +1,92 @@
+//
+//  QTryReadLocker.h
+//  shared/src/shared/QTryReadLocker.h
+//
+//  Created by Clément Brisset on 10/29/15.
+//  Copyright 2015 High Fidelity, Inc.
+//
+//  Distributed under the Apache License, Version 2.0.
+//  See the accompanying file LICENSE or http://www.apache.org/licenses/LICENSE-2.0.html
+//
+
+#ifndef hifi_QTryReadLocker_h
+#define hifi_QTryReadLocker_h
+
+#include <QtCore/QReadWriteLock>
+
+class QTryReadLocker {
+public:
+    QTryReadLocker(QReadWriteLock* readWriteLock);
+    QTryReadLocker(QReadWriteLock* readWriteLock, int timeout);
+    ~QTryReadLocker();
+    
+    bool isLocked() const;
+    
+    void unlock();
+    bool tryRelock();
+    bool tryRelock(int timeout);
+    
+    QReadWriteLock* readWriteLock() const;
+    
+private:
+    Q_DISABLE_COPY(QTryReadLocker)
+    quintptr q_val;
+};
+
+// Implementation
+inline QTryReadLocker::QTryReadLocker(QReadWriteLock *areadWriteLock) :
+    q_val(reinterpret_cast<quintptr>(areadWriteLock))
+{
+    Q_ASSERT_X((q_val & quintptr(1u)) == quintptr(0),
+               "QTryReadLocker", "QTryReadLocker pointer is misaligned");
+    tryRelock();
+}
+
+inline QTryReadLocker::QTryReadLocker(QReadWriteLock *areadWriteLock, int timeout) :
+    q_val(reinterpret_cast<quintptr>(areadWriteLock))
+{
+    Q_ASSERT_X((q_val & quintptr(1u)) == quintptr(0),
+               "QTryReadLocker", "QTryReadLocker pointer is misaligned");
+    tryRelock(timeout);
+}
+
+inline QTryReadLocker::~QTryReadLocker() {
+    unlock();
+}
+
+inline bool QTryReadLocker::isLocked() const {
+    return (q_val & quintptr(1u)) == quintptr(1u);
+}
+
+inline void QTryReadLocker::unlock() {
+    if (q_val && isLocked()) {
+        q_val &= ~quintptr(1u);
+        readWriteLock()->unlock();
+    }
+}
+
+inline bool QTryReadLocker::tryRelock() {
+    if (q_val && !isLocked()) {
+        if (readWriteLock()->tryLockForRead()) {
+            q_val |= quintptr(1u);
+            return true;
+        }
+    }
+    return false;
+}
+
+inline bool QTryReadLocker::tryRelock(int timeout) {
+    if (q_val && !isLocked()) {
+        if (readWriteLock()->tryLockForRead(timeout)) {
+            q_val |= quintptr(1u);
+            return true;
+        }
+    }
+    return false;
+}
+
+inline QReadWriteLock* QTryReadLocker::readWriteLock() const {
+    return reinterpret_cast<QReadWriteLock*>(q_val & ~quintptr(1u));
+}
+
+#endif // hifi_QTryReadLocker_h
\ No newline at end of file
diff --git a/libraries/shared/src/shared/QTryWriteLocker.h b/libraries/shared/src/shared/QTryWriteLocker.h
new file mode 100644
index 0000000000..319920f724
--- /dev/null
+++ b/libraries/shared/src/shared/QTryWriteLocker.h
@@ -0,0 +1,92 @@
+//
+//  QTryWriteLocker.h
+//  shared/src/shared/QTryWriteLocker.h
+//
+//  Created by Clément Brisset on 10/29/15.
+//  Copyright 2015 High Fidelity, Inc.
+//
+//  Distributed under the Apache License, Version 2.0.
+//  See the accompanying file LICENSE or http://www.apache.org/licenses/LICENSE-2.0.html
+//
+
+#ifndef hifi_QTryWriteLocker_h
+#define hifi_QTryWriteLocker_h
+
+#include <QtCore/QReadWriteLock>
+
+class QTryWriteLocker {
+public:
+    QTryWriteLocker(QReadWriteLock* readWriteLock);
+    QTryWriteLocker(QReadWriteLock* readWriteLock, int timeout);
+    ~QTryWriteLocker();
+    
+    bool isLocked() const;
+    
+    void unlock();
+    bool tryRelock();
+    bool tryRelock(int timeout);
+    
+    QReadWriteLock* readWriteLock() const;
+    
+private:
+    Q_DISABLE_COPY(QTryWriteLocker)
+    quintptr q_val;
+};
+
+// Implementation
+inline QTryWriteLocker::QTryWriteLocker(QReadWriteLock *readWriteLock) :
+    q_val(reinterpret_cast<quintptr>(readWriteLock))
+{
+    Q_ASSERT_X((q_val & quintptr(1u)) == quintptr(0),
+               "QTryWriteLocker", "QTryWriteLocker pointer is misaligned");
+    tryRelock();
+}
+
+inline QTryWriteLocker::QTryWriteLocker(QReadWriteLock *readWriteLock, int timeout) :
+    q_val(reinterpret_cast<quintptr>(readWriteLock))
+{
+    Q_ASSERT_X((q_val & quintptr(1u)) == quintptr(0),
+               "QTryWriteLocker", "QTryWriteLocker pointer is misaligned");
+    tryRelock(timeout);
+}
+
+inline QTryWriteLocker::~QTryWriteLocker() {
+    unlock();
+}
+
+inline bool QTryWriteLocker::isLocked() const {
+    return (q_val & quintptr(1u)) == quintptr(1u);
+}
+
+inline void QTryWriteLocker::unlock() {
+    if (q_val && isLocked()) {
+        q_val &= ~quintptr(1u);
+        readWriteLock()->unlock();
+    }
+}
+
+inline bool QTryWriteLocker::tryRelock() {
+    if (q_val && !isLocked()) {
+        if (readWriteLock()->tryLockForWrite()) {
+            q_val |= quintptr(1u);
+            return true;
+        }
+    }
+    return false;
+}
+
+inline bool QTryWriteLocker::tryRelock(int timeout) {
+    if (q_val && !isLocked()) {
+        if (readWriteLock()->tryLockForWrite(timeout)) {
+            q_val |= quintptr(1u);
+            return true;
+        }
+    }
+    return false;
+}
+
+inline QReadWriteLock* QTryWriteLocker::readWriteLock() const {
+    return reinterpret_cast<QReadWriteLock*>(q_val & ~quintptr(1u));
+}
+
+#endif // hifi_QTryWriteLocker_h
\ No newline at end of file