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authorPeter Breitenlohner <peb@mppmu.mpg.de>2012-10-26 07:13:09 +0000
committerPeter Breitenlohner <peb@mppmu.mpg.de>2012-10-26 07:13:09 +0000
commit74cc05c672add53f566ac385f117008e8c4b3eda (patch)
treece973a7d2e4814a20d52a55b1a2131d1515e9911 /Build/source/libs/icu/icu-50.1/common/mutex.h
parent6439fb8917718c4d620170e1459a1d9e7ab3c441 (diff)
icu 50.1 (50_rc)
git-svn-id: svn://tug.org/texlive/trunk@28087 c570f23f-e606-0410-a88d-b1316a301751
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+/*
+******************************************************************************
+*
+* Copyright (C) 1997-2012, International Business Machines
+* Corporation and others. All Rights Reserved.
+*
+******************************************************************************
+*/
+//----------------------------------------------------------------------------
+// File: mutex.h
+//
+// Lightweight C++ wrapper for umtx_ C mutex functions
+//
+// Author: Alan Liu 1/31/97
+// History:
+// 06/04/97 helena Updated setImplementation as per feedback from 5/21 drop.
+// 04/07/1999 srl refocused as a thin wrapper
+//
+//----------------------------------------------------------------------------
+#ifndef MUTEX_H
+#define MUTEX_H
+
+#include "unicode/utypes.h"
+#include "unicode/uobject.h"
+#include "umutex.h"
+
+U_NAMESPACE_BEGIN
+
+//----------------------------------------------------------------------------
+// Code within that accesses shared static or global data should
+// should instantiate a Mutex object while doing so. You should make your own
+// private mutex where possible.
+
+// For example:
+//
+// UMutex myMutex;
+//
+// void Function(int arg1, int arg2)
+// {
+// static Object* foo; // Shared read-write object
+// Mutex mutex(&myMutex); // or no args for the global lock
+// foo->Method();
+// // When 'mutex' goes out of scope and gets destroyed here, the lock is released
+// }
+//
+// Note: Do NOT use the form 'Mutex mutex();' as that merely forward-declares a function
+// returning a Mutex. This is a common mistake which silently slips through the
+// compiler!!
+//
+
+class U_COMMON_API Mutex : public UMemory {
+public:
+ inline Mutex(UMutex *mutex = NULL);
+ inline ~Mutex();
+
+private:
+ UMutex *fMutex;
+
+ Mutex(const Mutex &other); // forbid copying of this class
+ Mutex &operator=(const Mutex &other); // forbid copying of this class
+};
+
+inline Mutex::Mutex(UMutex *mutex)
+ : fMutex(mutex)
+{
+ umtx_lock(fMutex);
+}
+
+inline Mutex::~Mutex()
+{
+ umtx_unlock(fMutex);
+}
+
+// common code for singletons ---------------------------------------------- ***
+
+/**
+ * Function pointer for the instantiator parameter of
+ * SimpleSingleton::getInstance() and TriStateSingleton::getInstance().
+ * The function creates some object, optionally using the context parameter.
+ * The function need not check for U_FAILURE(errorCode).
+ */
+typedef void *InstantiatorFn(const void *context, UErrorCode &errorCode);
+
+/**
+ * Singleton struct with shared instantiation/mutexing code.
+ * Simple: Does not remember if a previous instantiation failed.
+ * Best used if the instantiation can really only fail with an out-of-memory error,
+ * otherwise use a TriStateSingleton.
+ * Best used via SimpleSingletonWrapper or similar.
+ * Define a static SimpleSingleton instance via the STATIC_SIMPLE_SINGLETON macro.
+ */
+struct SimpleSingleton {
+ void *fInstance;
+
+ /**
+ * Returns the singleton instance, or NULL if it could not be created.
+ * Calls the instantiator with the context if the instance has not been
+ * created yet. In a race condition, the duplicate may not be NULL.
+ * The caller must delete the duplicate.
+ * The caller need not initialize the duplicate before the call.
+ */
+ void *getInstance(InstantiatorFn *instantiator, const void *context,
+ void *&duplicate,
+ UErrorCode &errorCode);
+ /**
+ * Resets the fields. The caller must have deleted the singleton instance.
+ * Not mutexed.
+ * Call this from a cleanup function.
+ */
+ void reset() { fInstance=NULL; }
+};
+
+#define STATIC_SIMPLE_SINGLETON(name) static SimpleSingleton name={ NULL }
+
+/**
+ * Handy wrapper for a SimpleSingleton.
+ * Intended for temporary use on the stack, to make the SimpleSingleton easier to deal with.
+ * Takes care of the duplicate deletion and type casting.
+ */
+template<typename T>
+class SimpleSingletonWrapper {
+public:
+ SimpleSingletonWrapper(SimpleSingleton &s) : singleton(s) {}
+ void deleteInstance() {
+ delete (T *)singleton.fInstance;
+ singleton.reset();
+ }
+ T *getInstance(InstantiatorFn *instantiator, const void *context,
+ UErrorCode &errorCode) {
+ void *duplicate;
+ T *instance=(T *)singleton.getInstance(instantiator, context, duplicate, errorCode);
+ delete (T *)duplicate;
+ return instance;
+ }
+private:
+ SimpleSingleton &singleton;
+};
+
+/**
+ * Singleton struct with shared instantiation/mutexing code.
+ * Tri-state: Instantiation succeeded/failed/not attempted yet.
+ * Best used via TriStateSingletonWrapper or similar.
+ * Define a static TriStateSingleton instance via the STATIC_TRI_STATE_SINGLETON macro.
+ */
+struct TriStateSingleton {
+ void *fInstance;
+ UErrorCode fErrorCode;
+
+ /**
+ * Returns the singleton instance, or NULL if it could not be created.
+ * Calls the instantiator with the context if the instance has not been
+ * created yet. In a race condition, the duplicate may not be NULL.
+ * The caller must delete the duplicate.
+ * The caller need not initialize the duplicate before the call.
+ * The singleton creation is only attempted once. If it fails,
+ * the singleton will then always return NULL.
+ */
+ void *getInstance(InstantiatorFn *instantiator, const void *context,
+ void *&duplicate,
+ UErrorCode &errorCode);
+ /**
+ * Resets the fields. The caller must have deleted the singleton instance.
+ * Not mutexed.
+ * Call this from a cleanup function.
+ */
+ void reset();
+};
+
+#define STATIC_TRI_STATE_SINGLETON(name) static TriStateSingleton name={ NULL, U_ZERO_ERROR }
+
+/**
+ * Handy wrapper for a TriStateSingleton.
+ * Intended for temporary use on the stack, to make the TriStateSingleton easier to deal with.
+ * Takes care of the duplicate deletion and type casting.
+ */
+template<typename T>
+class TriStateSingletonWrapper {
+public:
+ TriStateSingletonWrapper(TriStateSingleton &s) : singleton(s) {}
+ void deleteInstance() {
+ delete (T *)singleton.fInstance;
+ singleton.reset();
+ }
+ T *getInstance(InstantiatorFn *instantiator, const void *context,
+ UErrorCode &errorCode) {
+ void *duplicate;
+ T *instance=(T *)singleton.getInstance(instantiator, context, duplicate, errorCode);
+ delete (T *)duplicate;
+ return instance;
+ }
+private:
+ TriStateSingleton &singleton;
+};
+
+U_NAMESPACE_END
+
+#endif //_MUTEX_
+//eof