From 5042e3cf0d3514552769e441f5aad590c8eaf967 Mon Sep 17 00:00:00 2001
From: kergoth <kergoth>
Date: Fri, 01 Nov 2002 00:10:42 +0000
Subject: Adding qmake in preperation for new build system

---
(limited to 'qmake/tools/qmutexpool.cpp')

diff --git a/qmake/tools/qmutexpool.cpp b/qmake/tools/qmutexpool.cpp
new file mode 100644
index 0000000..9ed2829
--- a/dev/null
+++ b/qmake/tools/qmutexpool.cpp
@@ -0,0 +1,130 @@
+#include "qmutexpool_p.h"
+
+#ifdef QT_THREAD_SUPPORT
+
+#include <qthread.h>
+#include <stdio.h>
+
+QMutexPool *qt_global_mutexpool = 0;
+
+// this is an internal class used only for inititalizing the global mutexpool
+class QGlobalMutexPoolInitializer
+{
+public:
+    inline QGlobalMutexPoolInitializer()
+    {
+	/*
+	  Purify will report a leak here. However, this mutex pool must be alive
+	  until *everything* in Qt has been destructed. Unfortunately there is
+	  no way to guarantee this, so we never destroy this mutex pool.
+	*/
+	qt_global_mutexpool = new QMutexPool( TRUE );
+    }
+};
+QGlobalMutexPoolInitializer qt_global_mutexpool_initializer;
+
+/*!
+    \class QMutexPool qmutexpool_p.h
+    \brief The QMutexPool class provides a pool of QMutex objects.
+
+    \internal
+
+    \ingroup thread
+
+    QMutexPool is a convenience class that provides access to a fixed
+    number of QMutex objects.
+
+    Typical use of a QMutexPool is in situations where it is not
+    possible or feasible to use one QMutex for every protected object.
+    The mutex pool will return a mutex based on the address of the
+    object that needs protection.
+
+    For example, consider this simple class:
+
+    \code
+    class Number {
+    public:
+	Number( double n ) : num ( n ) { }
+
+	void setNumber( double n ) { num = n; }
+	double number() const { return num; }
+
+    private:
+	double num;
+    };
+    \endcode
+
+    Adding a QMutex member to the Number class does not make sense,
+    because it is so small. However, in order to ensure that access to
+    each Number is protected, you need to use a mutex. In this case, a
+    QMutexPool would be ideal.
+
+    Code to calculate the square of a number would then look something
+    like this:
+
+    \code
+    void calcSquare( Number *num )
+    {
+	QMutexLocker locker( mutexpool.get( num ) );
+	num.setNumber( num.number() * num.number() );
+    }
+    \endcode
+
+    This function will safely calculate the square of a number, since
+    it uses a mutex from a QMutexPool. The mutex is locked and
+    unlocked automatically by the QMutexLocker class. See the
+    QMutexLocker documentation for more details.
+*/
+
+/*!
+    Constructs  a QMutexPool, reserving space for \a size QMutexes. If
+    \a recursive is TRUE, all QMutexes in the pool will be recursive
+    mutexes; otherwise they will all be non-recursive (the default).
+
+    The QMutexes are created when needed, and deleted when the
+    QMutexPool is destructed.
+*/
+QMutexPool::QMutexPool( bool recursive, int size )
+    : mutex( FALSE ), mutexes( size ), recurs( recursive )
+{
+    mutexes.fill( 0 );
+}
+
+/*!
+    Destructs a QMutexPool. All QMutexes that were created by the pool
+    are deleted.
+*/
+QMutexPool::~QMutexPool()
+{
+    QMutexLocker locker( &mutex );
+    QMutex **d = mutexes.data();
+    for ( int index = 0; (uint) index < mutexes.size(); index++ ) {
+	delete d[index];
+	d[index] = 0;
+    }
+}
+
+/*!
+    Returns a QMutex from the pool. QMutexPool uses the value \a
+    address to determine which mutex is retured from the pool.
+*/
+QMutex *QMutexPool::get( void *address )
+{
+    QMutex **d = mutexes.data();
+    int index = (int)( (ulong) address % mutexes.size() );
+
+    if ( ! d[index] ) {
+	// mutex not created, create one
+
+	QMutexLocker locker( &mutex );
+	// we need to check once again that the mutex hasn't been created, since
+	// 2 threads could be trying to create a mutex as the same index...
+	if ( ! d[index] ) {
+	    d[index] = new QMutex( recurs );
+	}
+    }
+
+    return d[index];
+}
+
+#endif
--
cgit v0.9.0.2