add PIReadWriteLock, PIReadLocker and PIWriteLocker

libs/main/thread/pireadwritelock.h

@@ -0,0 +1,130 @@
+/*! \file pireadwritelock.h
+ * \ingroup Read/Write lock
+ * \~\brief
+ * \~english Read/Write lock
+ * \~russian Блокировка чтения/записи
+ */
+/*
+    PIP - Platform Independent Primitives
+	PIReadWriteLock, PIReadLocker, PIWriteLocker
+	Ivan Pelipenko peri4ko@yandex.ru
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU Lesser General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU Lesser General Public License for more details.
+
+    You should have received a copy of the GNU Lesser General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#ifndef PIREADWRITELOCK_H
+#define PIREADWRITELOCK_H
+
+#include "piconditionvar.h"
+
+
+class PIP_EXPORT PIReadWriteLock {
+public:
+	NO_COPY_CLASS(PIReadWriteLock)
+
+	//! \~english Constructs %PIReadWriteLock.
+	//! \~russian Создает %PIReadWriteLock.
+	PIReadWriteLock();
+
+	//! \~english Destroy %PIReadWriteLock.
+	//! \~russian Деструктор %PIReadWriteLock.
+	~PIReadWriteLock();
+
+
+	//! \~english Lock for write. If already locked for write or read, than wait until all locks released.
+	//! \~russian Заблокировать на запись. Если уже заблокировано на запись или чтение, то ждёт освобождения блокировок.
+	void lockWrite();
+
+	//! \~english Try to lock for write. Returns if operation was successfull.
+	//! \~russian Пробует заблокировать на запись. Возвращает успех операции.
+	bool tryLockWrite();
+
+	//! \~english Try to lock for write for \"timeout\". Returns if operation was successfull (timeout has not expired).
+	//! \~russian Пробует заблокировать на запись в течении \"timeout\". Возвращает успех операции (не истек ли тайм-аут).
+	bool tryLockWrite(PISystemTime timeout);
+
+	//! \~english Release lock for write.
+	//! \~russian Освобождает блокировку на запись.
+	void unlockWrite();
+
+
+	//! \~english Lock for read. If already locked for write, than wait until write lock released.
+	//! \~russian Заблокировать на чтение. Если уже заблокировано на запись, то ждёт освобождения записывающей блокировки.
+	void lockRead();
+
+	//! \~english Try to lock for read. Returns if operation was successfull.
+	//! \~russian Пробует заблокировать на чтение. Возвращает успех операции.
+	bool tryLockRead();
+
+	//! \~english Try to lock for read for \"timeout\". Returns if operation was successfull (timeout has not expired).
+	//! \~russian Пробует заблокировать на чтение в течении \"timeout\". Возвращает успех операции (не истек ли тайм-аут).
+	bool tryLockRead(PISystemTime timeout);
+
+	//! \~english Release lock for read.
+	//! \~russian Освобождает блокировку на чтение.
+	void unlockRead();
+
+private:
+	int reading  = 0;
+	bool writing = false;
+	PIMutex mutex;
+	PIConditionVariable var;
+};
+
+
+class PIP_EXPORT PIReadLocker {
+public:
+	NO_COPY_CLASS(PIReadLocker);
+
+	//! \~english Constructs and lock for read %PIReadWriteLock "l" if "condition" is \c true.
+	//! \~russian Создается и блокирует на чтение %PIReadWriteLock "l" если "condition" \c true.
+	PIReadLocker(PIReadWriteLock & l, bool condition = true): rwl(l), cond(condition) {
+		if (cond) rwl.lockRead();
+	}
+
+	//! \~english Release read lock on %PIReadWriteLock if "condition" was \c true.
+	//! \~russian Освобождает блокировку на чтение %PIReadWriteLock если "condition" был \c true.
+	~PIReadLocker() {
+		if (cond) rwl.unlockRead();
+	}
+
+private:
+	PIReadWriteLock & rwl;
+	bool cond = true;
+};
+
+
+class PIP_EXPORT PIWriteLocker {
+public:
+	NO_COPY_CLASS(PIWriteLocker);
+
+	//! \~english Constructs and lock for write %PIReadWriteLock "l" if "condition" is \c true.
+	//! \~russian Создается и блокирует на запись %PIReadWriteLock "l" если "condition" \c true.
+	PIWriteLocker(PIReadWriteLock & l, bool condition = true): rwl(l), cond(condition) {
+		if (cond) rwl.lockWrite();
+	}
+
+	//! \~english Release write lock on %PIReadWriteLock if "condition" was \c true.
+	//! \~russian Освобождает блокировку на запись %PIReadWriteLock если "condition" был \c true.
+	~PIWriteLocker() {
+		if (cond) rwl.unlockWrite();
+	}
+
+private:
+	PIReadWriteLock & rwl;
+	bool cond = true;
+};
+
+
+#endif