77 lines
2.3 KiB
C++
77 lines
2.3 KiB
C++
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/** \file lispcleanupstack.h
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* Implementation of a cleanup stack for exception handling on platforms
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* that don't clean up the stack automatically after an exception
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* occurs. The macro's SAFEPUSH and SAFEPOP as defined in
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* plat/<plat>/lisptype.h define which cleanup handler
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* to use, so it can be configured differently for different platforms.
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*
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*/
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#ifndef __lispcleanupstack_h__
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#define __lispcleanupstack_h__
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#include "yacasbase.h"
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#include "grower.h"
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/** Base class that specifies one pure abstract method Delete.
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* Only classes derived from this one can be pushed onto
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* a cleanup stack. This in order to assure the cleanup code
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* knows where to find the destructor.
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*
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* Typical candidates for cleanup include places in the code that
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* have temporal global side effects that need to be finalized on,
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* Like opening a file for reading, reading and then closing. If
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* reading prematurely finishes through an exception, the file
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* should be closed.
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*/
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class LispBase : public YacasBase
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{
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public:
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virtual void Delete()=0;
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virtual ~LispBase(){};
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};
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/** Clean up stack that doesn't actually delete objects itself.
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* Use this clean up stack if the compiler generates
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* cleanup code itself (particularly for newer c++ compilers).
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* Alternatively SAFEPUSH and SAFEPOP can then be defined to do nothing.
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*/
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class LispCleanup : public YacasBase
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{
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public:
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inline LispCleanup() : iObjects() {}
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virtual ~LispCleanup();
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/// Push an object onto the cleanup stack for guarding
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virtual void Push(LispBase& aObject);
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/// Pop an object from the cleanup stack (the system is finished using it)
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virtual void Pop();
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/// Exception occurred: delete all objects on the stack, back to front.
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virtual void Delete();
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/** For testing purposes, verify that all places that pushed an object
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* popped it too.
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*/
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void CheckStackEmpty();
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protected:
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CArrayGrower<LispBase*, ArrOpsCustomPtr<LispBase> > iObjects;
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};
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/** Clean up stack that deletes objects itself when needed.
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* Use this clean up stack if the compiler doesn't generate
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* cleanup code itself (particularly for older c++ compilers).
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*/
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class DeletingLispCleanup : public LispCleanup
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{
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public:
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virtual ~DeletingLispCleanup();
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virtual void Push(LispBase& aObject);
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virtual void Pop();
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virtual void Delete();
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};
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#endif
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