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Diffstat (limited to 'sal/inc/rtl/unload.h')
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diff --git a/sal/inc/rtl/unload.h b/sal/inc/rtl/unload.h deleted file mode 100644 index 4ac4f718e..000000000 --- a/sal/inc/rtl/unload.h +++ /dev/null @@ -1,318 +0,0 @@ -/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */ -/************************************************************************* - * - * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. - * - * Copyright 2000, 2010 Oracle and/or its affiliates. - * - * OpenOffice.org - a multi-platform office productivity suite - * - * This file is part of OpenOffice.org. - * - * OpenOffice.org is free software: you can redistribute it and/or modify - * it under the terms of the GNU Lesser General Public License version 3 - * only, as published by the Free Software Foundation. - * - * OpenOffice.org 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 version 3 for more details - * (a copy is included in the LICENSE file that accompanied this code). - * - * You should have received a copy of the GNU Lesser General Public License - * version 3 along with OpenOffice.org. If not, see - * <http://www.openoffice.org/license.html> - * for a copy of the LGPLv3 License. - * - ************************************************************************/ -#ifndef _RTL_UNLOAD_H_ -#define _RTL_UNLOAD_H_ - -#include <sal/types.h> -#include <osl/time.h> -#include <osl/interlck.h> -#include <osl/module.h> - -///@HTML -/** @file -The API enables an effective way of unloading libraries in a centralized way. -The mechanism ensures that used libraries are not unloaded. This prevents -crashes if library code is being used after unloading the library. -The unloading mechanism currently only works with libraries which contain -UNO services. A library cannot be unloaded if one of the following conditions -apply - -<ul> -<li>An instance is still referenced </li> -<li>A module has been loaded without registering it </li> -<li>The service manager has created a one instance service </li> -<li>A service instance has been added to an UNO context </li> -</ul> - -<b>Notification Mechanism</b> -The API provides a notification mechanism. Clients can use it to do clean up, -such as releasing cached references, in order to allow modules to be unloaded. -As long as someone holds a reference to an object whose housing module -supports unloading the module cannot be unloaded.<p> - -Because of the inherent danger of crashing the application by using this API -all instances which control threads should be registered listeners. On -notification they have to ensure that their threads assume a safe state, that -is, they run outside of modules which could be unloaded and do not jump -back into module code as a result of a finished function call. In other words, -there must not be an address of the module on the thread's stack. -<p> -Since current operating systems lack APIs in respect to controlling the -position of threads within libraries, it would be a major effort to comply with -that recommendation. The best and most efficient way of handling the unloading -scenario is to let all threads, except for the main thread, die in case of a -notification. -<p> -Use this API with great care because it might crash the application. See the -respective documentation (Library Unloading) on the udk.openoffice.org web site. -*/ - - -/** -A library which supports unloading has to implement and export a function -called <code>component_canUnload</code>. <p> -If the function returns <code>sal_True</code> then the module can be safely unloaded. -That is the case when there are no external references to code within the -library. In case a module houses UNO components then the function must return -<code>sal_False</code> after the first factory has been handed out. The function then -continues to return <code>sal_False</code> as long as there is at least one object (factory -or service instance) which originated from the module.<p> - -Libraries which not only contain UNO components (or none at all) have to -provide a means to control whether they can be unloaded or not, e.g. However, -there is no concept yet. <p> - -The argument <code>pTime</code> is an optional out-parameter. If the return value is -<code>sal_True</code> then <code>pTime</code> reflects a point in time since -when the module could have -been unloaded. Since that time the function would have continually returned -<code>sal_True</code> up to the present. The value of <code>pTime</code> is -important for the decision -as to a module will be unloaded. When someone initiates the unloading of -modules by calling <code>rtl_unloadUnusedModules</code> then the caller can specify a time -span with the effect that only those modules are unloaded which are unused at -least for that amount of time. If <code>component_canUnload</code> does not -fill in <code>pTime</code> -then the module is unloaded immediately.<p> - -<code>component_canUnload</code> is implicitly called by <code>rtl_unloadUnusedModules -</code>. There is no need to call the function directly. -*/ -#define COMPONENT_CANUNLOAD "component_canUnload" -typedef sal_Bool (SAL_CALL * component_canUnloadFunc)( TimeValue* pTime); - - -/** C-interface for a module reference counting - */ -#ifdef __cplusplus -extern "C" -{ -#endif - -/** -By registering a module, one declares that a module supports the -unloading mechanism. One registers a module by calling this function.<p> - -A module can only be unloaded from memory when it has been registered -as many times as it has been loaded. The reason is that a library can -be "loaded" several times by <code>osl_loadModule</code> -within the same process. The -function will then return the same module handle because the library will -effectively only be loaded once. To remove the library from memory it is -necessary to call <code>osl_unloadModule</code> as often as <code> -osl_loadModule</code> was called. The -function <code>rtl_unloadUnusedModules</code> calls <code>osl_unloadModule</code> -for a module as many -times as it was registered. If, for example, a module has been registered one -time less then <code>osl_loadModule</code> has been called and the module can be unloaded -then it needs a call to <code>rtl_unloadUnusedModules</code> and an explicit call to -<code>osl_unloadModule</code> to remove the module from memory. <p> - -A module must be registered every time it has been loaded otherwise the -unloading mechanism is not effective.<p> - -Before a module is registered, one has to make sure that the module is in a -state that prevents it from being unloaded. In other words, -<code>component_canUnload</code> must return <code>sal_False</code>. Assuming that -<code>component_canUnload</code> -returns <code>sal_True</code> and it is registered regardless, then a call to -<code>rtl_unloadUnusedModules</code> causes the module to be unloaded. This unloading can -be set off by a different thread and the thread which registered the module is -"unaware" of this. Then when the first thread tries to obtain a factory or -calls another function in the module, the application will crash, because the -module has been unloaded before. Therefore one has to ensure that the module -cannot be unloaded before it is registered. This is simply done by obtaining a -factory from the module. As long as a factory or some other object, which has -been created by the factory, is alive, the <code>component_canUnload</code> function will -return <code>sal_False</code>.<p> -Loading and registering have to be in this order:<br> -<ul> -<li>load a library (<code>osl_loadModule</code>)</li> -<li>get the <code>component_getFactory</code> function and get a factory</li> -<li>register the module (rtl_registerModuleForUnloading</li> -</ul> -Usually the service manager is used to obtain an instance of a service. -The service manager registers all modules which support the unloading mechanism. -When the service manager is used to get service instances than one does not -have to bother about registering. - -@param module a module handle as is obtained by osl_loadModule -@return sal_True - the module could be registered for unloading, sal_False otherwise -*/ -sal_Bool SAL_CALL rtl_registerModuleForUnloading( oslModule module); - -/** -The function revokes the registration of a module. By calling the function for -a previously registered module one prevents the module from being unloaded by -this unloading mechanism. However, in order to completely unregister the module -it is necessary to call the function as often as the module has been registered. -<p> -<code>rtl_unloadUnusedModules</code> unregisters the modules which it unloads. Therefore -there is no need to call this function unless one means to prevent the unloading of a module. - -@param module a module handle as is obtained by osl_loadModule -*/ -void SAL_CALL rtl_unregisterModuleForUnloading( oslModule module); -/** -This function sets off the unloading mechanism. At first it notifies the -unloading listeners in order to give them a chance to do cleanup and get -their threads in a safe state. Then all registered modules are asked if they -can be unloaded. That is, the function calls component_canUnload on every -registered module. If <code>sal_True</code> is returned then <code>osl_unloadModule</code> -is called for the belonging module as often as it is registered. -<p> -A call to <code>osl_unloadModule</code> does not guarantee that the module is unloaded even -if its <code>component_canUnload</code> function returns <code>sal_True</code>. -<p> -The optional in-parameter <code>libUnused</code> specifies a period of time which a library -must be unused in order to qualify for being unloaded. By using this argument -one can counter the multithreading problem as described further above. It is in -the responsibility of the user of this function to provide a timespan big enough -to ensure that all threads are out of modules (see <code>component_canUnload</code>). -<p> -The service managers which have been created by functions such as -<code>createRegistryServiceFactory</code> (declared in cppuhelper/servicefactory.hxx) are -registered listeners and release the references to factories on notification. - - -@param libUnused span of time that a module must be unused to be unloaded. the -argument is optional. -*/ -void SAL_CALL rtl_unloadUnusedModules( TimeValue* libUnused); - -/** -rtl_addUnloadingListener takes an argument of this type. - -@param id - The value that has been passed as second argument to rtl_addUnloadingListener -*/ -typedef void (SAL_CALL *rtl_unloadingListenerFunc)(void* id); -/** -The function registered an unloading listener. The callback argument is a -function which is called when the unloading procedure has been initiated by a call to -<code>rtl_unloadUnusedLibraries</code>. The second argument is used to distinguish between different -listener instances and may be <code>NULL</code>. It will be passed as argument when the callback -function is being called. The return value identifies the registered listener and will -be used for removing the listener later on. If the same listener is added more then -once then every registration is treated as if made for a different listener. That is, -a different cookie is returned and the callback function will be called as many times -as it has been registered. -@param callback - a function that is called to notify listeners. -@param this - a value to distinguish different listener instances -@return identifier which is used in rtl_removeUnloadingListener -*/ -sal_Int32 SAL_CALL rtl_addUnloadingListener( rtl_unloadingListenerFunc callback, void* _this); - -/** -Listeners (the callback functions) must be unregistered before the listener code -becomes invalid. That is, if a module contains listener code, namely callback -functions of type <code>rtl_unloadingListenerFunc</code>, then those functions must not be -registered when <code>component_canUnload</code> returns <code>sal_True</code>. - -@param cookie is an identifier as returned by <code>rtl_addUnloadingListener</code> function. -*/ -void SAL_CALL rtl_removeUnloadingListener( sal_Int32 cookie ); - - -/** -Pointers to <code>rtl_ModuleCount</code> are passed as arguments to the default factory creator -functions: <code>createSingleComponentFactory</code>, <code>createSingleFactory</code>, -<code>createOneInstanceFactory</code>. -The factory implementation is calling <code>rtl_ModuleCount.acquire</code> when it is being -constructed and it is calling <code>rtl_ModuleCount.release</code>. The implementations of -<code>acquire</code> -and <code>release</code> should influence the return value of <code>component_canUnload</code> -in a way that it -returns <code>sal_False</code> after <code>acquire</code> has been called. That is the module will not be unloaded -once a default factory has been created. A call to <code>release</code> may cause -<code>component_canUnload</code> to return <code>sal_False</code>, but only if there are -no object alive which -originated from the module. These objects are factory instances and the service instances -which have been created by these factories. -<p> -It is not necessary to synchronize <code>acquire</code> and <code>release</code> as a whole. -Simply sychronize the -access to a counter variable, e.g. the <code>rtl_moduleCount_release</code> implementation: -<pre> -extern "C" void rtl_moduleCount_acquire(rtl_ModuleCount * that ) -{ - rtl_StandardModuleCount* pMod= (rtl_StandardModuleCount*)that; - osl_incrementInterlockedCount( &pMod->counter); -} -</pre> -The SAL library offers functions that can be used for <code>acquire</code> and <code>release</code>. See struct -<code>_rtl_StandardModuleCount</code>. -*/ -typedef struct _rtl_ModuleCount -{ - void ( SAL_CALL * acquire ) ( struct _rtl_ModuleCount * that ); - void ( SAL_CALL * release ) ( struct _rtl_ModuleCount * that ); -}rtl_ModuleCount; - - -#define MODULE_COUNT_INIT \ -{ {rtl_moduleCount_acquire,rtl_moduleCount_release}, rtl_moduleCount_canUnload, 0, {0, 0}} - -/** -This struct can be used to implement the unloading mechanism. To make a UNO library -unloadable create one global instance of this struct in the module. To initialize it one -uses the MODULE_COUNT_INIT macro. - -<pre>rtl_StandardModuleCount globalModuleCount= MODULE_COUNT_INIT</pre>; -*/ -typedef struct _rtl_StandardModuleCount -{ - rtl_ModuleCount modCnt; - sal_Bool ( *canUnload ) ( struct _rtl_StandardModuleCount* a, TimeValue* libUnused); - oslInterlockedCount counter; - TimeValue unusedSince; -} rtl_StandardModuleCount; - -/** Default implementation for <code>rtl_ModuleCount.acquire</code>. Use this function along with -<code>rtl_StandardModuleCount</code>. -*/ -void rtl_moduleCount_acquire(rtl_ModuleCount * that ); -/** Default implementation for <code>rtl_ModuleCount.release</code>. -Use this function along with -<code>rtl_StandardModuleCount</code>. -*/ -void rtl_moduleCount_release( rtl_ModuleCount * that ); - -/** Default implementation for <code>component_canUnload</code>. Use this function along with -<code>rtl_StandardModuleCount</code>. -*/ -sal_Bool rtl_moduleCount_canUnload( rtl_StandardModuleCount * that, TimeValue* libUnused); - - -#ifdef __cplusplus -} -#endif - - -#endif - -/* vim:set shiftwidth=4 softtabstop=4 expandtab: */ |