User Interface Memory Managment - Revision history

Paulb at 18:16, 31 October 2007

2007-10-31T18:16:41Z

← Older revision		Revision as of 18:16, 31 October 2007
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	Agents are probably the number one cause of memory leaks inside EiffelStudio as they could be contained in a live object but references a recycled one. As the agent references a recycled object the GC retains the recycled object because there is still an active reference to it.		Agents are probably the number one cause of memory leaks inside EiffelStudio as they could be contained in a live object but references a recycled one. As the agent references a recycled object the GC retains the recycled object because there is still an active reference to it.

	[https://svn.eiffel.com/eiffelstudio/trunk/Src/Eiffel/interface/new_graphical/managers/eb_recyclable.e EB_RECYCLABLE] provides operations to facilitate here also. There are two routines to use when extending a sequence of actions and have the action automatically removed when the functioning object is recycled; <code>register_action</code> and <code>register_kamikaze_action</code>. <code>register_action</code> simply takes an [~~http~~://~~freeelks.~~svn.~~sourceforge~~.~~net~~/~~viewvc~~/~~freeelks~~/~~trunk~~/library/~~kernel~~/action_sequence.e~~?view=markup~~ ACTION_SEQUENCE] and an action. It does the necessary extension to the action sequence and will prune the action when the object in which <code>register_action</code> was class is recycled. <code>register_kamikaze_action</code> performs in the same way as <code>register_action</code> does except that it extends the action sequence with the action to be called only once. Generally kamikaze actions are removed from the action sequence when the actions are called. However it is possible that the action sequence is never executed, after the kamikaze action has been added, so the action never pruned from the list of callees. This too can cause a memory leaks.		[https://svn.eiffel.com/eiffelstudio/trunk/Src/Eiffel/interface/new_graphical/managers/eb_recyclable.e EB_RECYCLABLE] provides operations to facilitate here also. There are two routines to use when extending a sequence of actions and have the action automatically removed when the functioning object is recycled; <code>register_action</code> and <code>register_kamikaze_action</code>. <code>register_action</code> simply takes an [https://svn.eiffel.com/eiffelstudio/trunk/Src/library/base/ise/event/action_sequence.e ACTION_SEQUENCE] and an action. It does the necessary extension to the action sequence and will prune the action when the object in which <code>register_action</code> was class is recycled. <code>register_kamikaze_action</code> performs in the same way as <code>register_action</code> does except that it extends the action sequence with the action to be called only once. Generally kamikaze actions are removed from the action sequence when the actions are called. However it is possible that the action sequence is never executed, after the kamikaze action has been added, so the action never pruned from the list of callees. This too can cause a memory leaks.

	{{Warning\|<code>register_action</code> and <code>register_kamikaze_action</code> come in a basic, generic use form so they can be used with any action sequence. This does removed the static compile time analysis so be careful when using an agent with an action sequence that the open arguments match. Failure to do so will result in a segmentation violation at runtime.}}		{{Warning\|<code>register_action</code> and <code>register_kamikaze_action</code> come in a basic, generic use form so they can be used with any action sequence. This does removed the static compile time analysis so be careful when using an agent with an action sequence that the open arguments match. Failure to do so will result in a segmentation violation at runtime.}}

Paulb at 18:15, 31 October 2007

2007-10-31T18:15:11Z

← Older revision		Revision as of 18:15, 31 October 2007
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	[https://svn.eiffel.com/eiffelstudio/trunk/Src/Eiffel/interface/new_graphical/managers/eb_recyclable.e EB_RECYCLABLE] is not a special class or is anyway known by the Eiffel compiler. That means unless <code>recycle</code> is called on an object implementing [https://svn.eiffel.com/eiffelstudio/trunk/Src/Eiffel/interface/new_graphical/managers/eb_recyclable.e EB_RECYCLABLE], it wont be recycled. For the time being [https://svn.eiffel.com/eiffelstudio/trunk/Src/Eiffel/interface/new_graphical/managers/eb_recyclable.e EB_RECYCLABLE] does not implement [http://freeelks.svn.sourceforge.net/viewvc/freeelks/trunk/library/kernel/disposable.e?view=markup DISPOSABLE] so the GC will be of no help.		[https://svn.eiffel.com/eiffelstudio/trunk/Src/Eiffel/interface/new_graphical/managers/eb_recyclable.e EB_RECYCLABLE] is not a special class or is anyway known by the Eiffel compiler. That means unless <code>recycle</code> is called on an object implementing [https://svn.eiffel.com/eiffelstudio/trunk/Src/Eiffel/interface/new_graphical/managers/eb_recyclable.e EB_RECYCLABLE], it wont be recycled. For the time being [https://svn.eiffel.com/eiffelstudio/trunk/Src/Eiffel/interface/new_graphical/managers/eb_recyclable.e EB_RECYCLABLE] does not implement [http://freeelks.svn.sourceforge.net/viewvc/freeelks/trunk/library/kernel/disposable.e?view=markup DISPOSABLE] so the GC will be of no help.

	The tool foundation implementation is [[EiffelStudio Foundations]] ([https://svn.eiffel.com/eiffelstudio/trunk/Src/Eiffel/interface/graphical/foundations/tools/es_tool.e ES_TOOL] and [https://svn.eiffel.com/eiffelstudio/trunk/Src/Eiffel/interface/graphical/foundations/tools/~~es_tool_panel~~.e ~~ES_TOOL_PANEL~~]) implement [https://svn.eiffel.com/eiffelstudio/trunk/Src/Eiffel/interface/new_graphical/managers/eb_recyclable.e EB_RECYCLABLE] and are automatically recycled when and as needed. However, this is one of the few cases. For example, the dialog foundation implementation in [[EiffelStudio Foundations]] ([[ES_DIALOG]]) '''does not''' call <code>recycle</code> automatically when close as a dialog may be reused. In that respect a dialog object should explicitly call <code>recycle</code> when no longer needed or to be automatically recycled by calling <code>auto_recycle</code>.		The tool foundation implementation is [[EiffelStudio Foundations]] ([https://svn.eiffel.com/eiffelstudio/trunk/Src/Eiffel/interface/graphical/foundations/tools/es_tool.e ES_TOOL] and [https://svn.eiffel.com/eiffelstudio/trunk/Src/Eiffel/interface/graphical/foundations/tools/es_dockable_tool_panel.e ES_DOCKABLE_TOOL_PANEL]) implement [https://svn.eiffel.com/eiffelstudio/trunk/Src/Eiffel/interface/new_graphical/managers/eb_recyclable.e EB_RECYCLABLE] and are automatically recycled when and as needed. However, this is one of the few cases. For example, the dialog foundation implementation in [[EiffelStudio Foundations]] ([https://svn.eiffel.com/eiffelstudio/trunk/Src/Eiffel/interface/graphical/foundations/dialogs/es_dialog.e ES_DIALOG]) '''does not''' call <code>recycle</code> automatically when close as a dialog may be reused. In that respect a dialog object should explicitly call <code>recycle</code> when no longer needed or to be automatically recycled by calling <code>auto_recycle</code>.

	== Detecting Memory Leaks ==		== Detecting Memory Leaks ==

Paulb at 18:13, 31 October 2007

2007-10-31T18:13:39Z

Show changes

Paulb at 18:04, 31 October 2007

2007-10-31T18:04:32Z

Paulb at 17:53, 31 October 2007

2007-10-31T17:53:10Z

← Older revision		Revision as of 17:53, 31 October 2007
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	{{Warning\|<code>register_action</code> and <code>register_kamikaze_action</code> come in a basic, generic use form so they can be used with any action sequence. This does removed the static compile time analysis so be careful when using an agent with an action sequence that the open arguments match. Failure to do so will result in a segmentation violation at runtime.}}		{{Warning\|<code>register_action</code> and <code>register_kamikaze_action</code> come in a basic, generic use form so they can be used with any action sequence. This does removed the static compile time analysis so be careful when using an agent with an action sequence that the open arguments match. Failure to do so will result in a segmentation violation at runtime.}}

	== No Magic Here ==		=== No Magic Here ===
	[[EB_RECYCLABLE]] is not a special class or is anyway known by the Eiffel compiler. That means unless <code>recycle</code> is called on an object implementing [[EB_RECYCLABLE]], it wont be recycled. For the time being [[EB_RECYCLABLE]] does not implement [[DISPOSABLE]] so the GC will be of no help.		[[EB_RECYCLABLE]] is not a special class or is anyway known by the Eiffel compiler. That means unless <code>recycle</code> is called on an object implementing [[EB_RECYCLABLE]], it wont be recycled. For the time being [[EB_RECYCLABLE]] does not implement [[DISPOSABLE]] so the GC will be of no help.

Paulb at 17:52, 31 October 2007

2007-10-31T17:52:44Z

← Older revision		Revision as of 17:52, 31 October 2007
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	[[Category:EiffelStudio]]		[[Category:EiffelStudio]]
	[[Category:Extending_EiffelStudio]]		[[Category:Extending_EiffelStudio]]
	~~{{UnderConstruction}}~~
	To be a good tool citizen inside EiffelStudio tools must properly handle resource manager above that provided by the Eiffel [[Garbage Collector\|garbage collector]] (GC). When working with any UI aspects in [[EiffelStudio]] objects should be "recyclable".		To be a good tool citizen inside EiffelStudio tools must properly handle resource manager above that provided by the Eiffel [[Garbage Collector\|garbage collector]] (GC). When working with any UI aspects in [[EiffelStudio]] objects should be "recyclable".

Paulb: /* Locating Memory Leaks */

2007-10-31T17:52:26Z

Locating Memory Leaks

← Older revision		Revision as of 17:52, 31 October 2007
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	* Enter a regular expression in the '''Type filter'''. For example, to show all EiffelStudio UI classes you would use: <code>^ES_\|^EB_</code>		* Enter a regular expression in the '''Type filter'''. For example, to show all EiffelStudio UI classes you would use: <code>^ES_\|^EB_</code>

	== Locating Memory Leaks ==		=== Locating Memory Leaks ===
	After you have found a memory leak, it is time to drill down and find out where the leak is occurring. The Memory Tool has implicit knowledge of [[EB_RECYCLABLE]] and displays an object's recycled state. In the example image shown in the previous section <code>EB_DEVELOPMENT_WINDOW_AGENT</code> has two live instances in the object map. The first has not been recycled as it is in use by the first opened window. The second instance however has been recycled, and even so still leaves two references preventing the [[Garbage Collector\|garbage collector]] from reclaiming the object.		After you have found a memory leak, it is time to drill down and find out where the leak is occurring. The Memory Tool has implicit knowledge of [[EB_RECYCLABLE]] and displays an object's recycled state. In the example image shown in the previous section <code>EB_DEVELOPMENT_WINDOW_AGENT</code> has two live instances in the object map. The first has not been recycled as it is in use by the first opened window. The second instance however has been recycled, and even so still leaves two references preventing the [[Garbage Collector\|garbage collector]] from reclaiming the object.

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	This could be a nightmare to find but with the help of the debugger and a well placed breakpoint the agent routine can be located.		This could be a nightmare to find but with the help of the debugger and a well placed breakpoint the agent routine can be located.

	=== Locating an Agent ===		==== Locating an Agent ====

	{{Note\|In order to locate an agent leak you must be debugging EiffelStudio from a finalized version of EiffelStudio, performing the leak analysis on the debugged version of EiffelStudio.}}		{{Note\|In order to locate an agent leak you must be debugging EiffelStudio from a finalized version of EiffelStudio, performing the leak analysis on the debugged version of EiffelStudio.}}

Paulb: /* Locating an Agent */

2007-10-31T17:52:02Z

Locating an Agent

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	* In a debugger '''Watch Tool''' add the expression <code>a_row.data</code>.		* In a debugger '''Watch Tool''' add the expression <code>a_row.data</code>.
	* Expand the expression result and the debugger shows the name of the agent, which you can navigate to using pick and drop or the context menu.		* Expand the expression result and the debugger shows the name of the agent, which you can navigate to using pick and drop or the context menu.
	* Examine the callers of the agent and locate the area where it's added to an action sequence, or set on an object, and be sure to prune it from the. sequence or unset it in the object's <code>EB_RECYCLABLE.internal_recycle</code>		* Examine the callers of the agent and locate the area where it's added to an action sequence, or set on an object, and be sure to prune it from the action sequence or unset it in the object's <code>EB_RECYCLABLE.internal_recycle</code>. Alternatively you can use the [[User_Interface_Memory_Managment#Automatic Recycling\|automatic recycling]] facilities of [[EB_RECYCLABLE]] to register the agent.

Paulb: /* Locating an Agent */

2007-10-31T17:49:19Z

Locating an Agent

← Older revision		Revision as of 17:49, 31 October 2007
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	* Now in the debugged version of [[EiffelStudio]] collapse the row (if it's not already) displaying the object of a [[PROCEDURE]], [[FUNCTION]] or [[PREDICATE]] type and then expanded it again.		* Now in the debugged version of [[EiffelStudio]] collapse the row (if it's not already) displaying the object of a [[PROCEDURE]], [[FUNCTION]] or [[PREDICATE]] type and then expanded it again.

	The debugger will ~~not~~ be broken into at the place breakpoint.		The debugger will now be broken into at the place breakpoint.

	* In a debugger '''Watch Tool''' add the expression <code>a_row.data</code>.		* In a debugger '''Watch Tool''' add the expression <code>a_row.data</code>.
	* Expand the expression result and the debugger shows the name of the agent, which you can navigate to using pick and drop or the context menu.		* Expand the expression result and the debugger shows the name of the agent, which you can navigate to using pick and drop or the context menu.
	* Examine the callers of the agent and locate the area where it's added to an action sequence, or set on an object, and be sure to prune it from the. sequence or unset it in the object's <code>EB_RECYCLABLE.internal_recycle</code>		* Examine the callers of the agent and locate the area where it's added to an action sequence, or set on an object, and be sure to prune it from the. sequence or unset it in the object's <code>EB_RECYCLABLE.internal_recycle</code>

Paulb: /* Detecting Memory Leaks */

2007-10-31T17:47:05Z

Detecting Memory Leaks

← Older revision		Revision as of 18:04, 31 October 2007
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	== Recycling ==		== Recycling ==
	Many UI classes inside [[EiffelStudio]] inherit a class [[EB_RECYCLABLE]]. It's purpose is to clean up resources and code links to other objects that may causes a memory leaks. As the old adage goes: "Prevention is always better than cure"		Many UI classes inside [[EiffelStudio]] inherit a class [[https://svn.eiffel.com/eiffelstudio/trunk/Src/Eiffel/interface/new_graphical/managers/eb_recyclable.e\|EB_RECYCLABLE]]. It's purpose is to clean up resources and code links to other objects that may causes a memory leaks. As the old adage goes: "Prevention is always better than cure"

	== Using EB_RECYCLABLE ==		== Using EB_RECYCLABLE ==
	To use [[EB_RECYCLABLE]] one has to simply inherit it and implement the deferred routine <code>internal_recycle</code> where you should explicitly recycle and object on the Current class instance that are no longer required, prune agents added to action sequences and generally unset entities of auxiliary objects to prevent memory leaks.		To use [[https://svn.eiffel.com/eiffelstudio/trunk/Src/Eiffel/interface/new_graphical/managers/eb_recyclable.e\|EB_RECYCLABLE]] one has to simply inherit it and implement the deferred routine <code>internal_recycle</code> where you should explicitly recycle and object on the Current class instance that are no longer required, prune agents added to action sequences and generally unset entities of auxiliary objects to prevent memory leaks.

	It's not recommended to detach class attributes in <code>internal_recycle</code> unless necessary because of the auto-recycling capabilities of [[EB_RECYCLABLE]]. Instead redefine <code>internal_detach_entities</code> to perform explicit detachment.		It's not recommended to detach class attributes in <code>internal_recycle</code> unless necessary because of the auto-recycling capabilities of [[https://svn.eiffel.com/eiffelstudio/trunk/Src/Eiffel/interface/new_graphical/managers/eb_recyclable.e\|EB_RECYCLABLE]]. Instead redefine <code>internal_detach_entities</code> to perform explicit detachment.

	{{Note\|Much of the EiffelStudio code base includes detachment of entities in internal_recycle because the auto-recycle functionality was performed by [[~~ES_RECYCLER~~]] in the [[6.0]] release. [[~~ES_RECYCLER~~]] is deprecated and should not be use.}}		{{Note\|Much of the EiffelStudio code base includes detachment of entities in internal_recycle because the auto-recycle functionality was performed by [[https://svn.eiffel.com/eiffelstudio/trunk/Src/Eiffel/interface/new_graphical/managers/eb_recycler.e\|EB_RECYCLER]] in the [[http://eiffelsoftware.origo.ethz.ch/index.php/EiffelStudio_Releases\|6.0]] release. [[https://svn.eiffel.com/eiffelstudio/trunk/Src/Eiffel/interface/new_graphical/managers/eb_recycler.e\|EB_RECYCLER]] is deprecated and should not be use.}}

	=== Automatic Recycling ===		=== Automatic Recycling ===
	The whole process of explict recycling in <code>internal_recycle</code> is fraught with potential bug scenarios. Forgetting or being unaware that a created object is in fact a recyclable object can cause a leak. This is where automatic recycling comes in.		The whole process of explict recycling in <code>internal_recycle</code> is fraught with potential bug scenarios. Forgetting or being unaware that a created object is in fact a recyclable object can cause a leak. This is where automatic recycling comes in.

	The automatic recycling capabilities of [[EB_RECYCLABLE]] does not care if an object is actually "recyclable" as it may not be statically but could be dynamically. In addition an object may have started out non-recyclable but was changed somewhere down the line to implement [[EB_RECYCLABLE]]. In that respect objects created in a class implementing [[EB_RECYCLABLE]] and should be cleaned up when the container object is recycled should use the automatic recycling facilities.		The automatic recycling capabilities of [[https://svn.eiffel.com/eiffelstudio/trunk/Src/Eiffel/interface/new_graphical/managers/eb_recyclable.e\|EB_RECYCLABLE]] does not care if an object is actually "recyclable" as it may not be statically but could be dynamically. In addition an object may have started out non-recyclable but was changed somewhere down the line to implement [[https://svn.eiffel.com/eiffelstudio/trunk/Src/Eiffel/interface/new_graphical/managers/eb_recyclable.e\|EB_RECYCLABLE]]. In that respect objects created in a class implementing [[https://svn.eiffel.com/eiffelstudio/trunk/Src/Eiffel/interface/new_graphical/managers/eb_recyclable.e\|EB_RECYCLABLE]] and should be cleaned up when the container object is recycled should use the automatic recycling facilities.

	=== Automatic Recycle and Destroy ===		=== Automatic Recycle and Destroy ===
	[[EB_RECYCLABLE]] provides two routines for descending classes to use; <code>auto_recycle</code> and <code>delayed_auto_recycle</code>. <code>auto_recycle</code> simply accepts an object of type [[ANY]] and if that object implements [[EB_RECYCLABLE]], it will be recycled when the container object is. <code>delayed_auto_recycle</code> works a little different in that it takes an agent. The agent is used to "fetch" the recyclable object at recycle-time. This is useful when objects are dynamically or lazily created, there is uncertainly about the attached state of an entity of an object or if a object's attribute is constantly changing.		[[https://svn.eiffel.com/eiffelstudio/trunk/Src/Eiffel/interface/new_graphical/managers/eb_recyclable.e\|EB_RECYCLABLE]] provides two routines for descending classes to use; <code>auto_recycle</code> and <code>delayed_auto_recycle</code>. <code>auto_recycle</code> simply accepts an object of type [[ANY]] and if that object implements [[https://svn.eiffel.com/eiffelstudio/trunk/Src/Eiffel/interface/new_graphical/managers/eb_recyclable.e\|EB_RECYCLABLE]], it will be recycled when the container object is. <code>delayed_auto_recycle</code> works a little different in that it takes an agent. The agent is used to "fetch" the recyclable object at recycle-time. This is useful when objects are dynamically or lazily created, there is uncertainly about the attached state of an entity of an object or if a object's attribute is constantly changing.

	{{Note\|Automatic recycling does not detach the object which was automatically recycled. If an object must detached to prevent memory leaks then a container object should define <code>internal_detach_entities</code>.}}		{{Note\|Automatic recycling does not detach the object which was automatically recycled. If an object must detached to prevent memory leaks then a container object should define <code>internal_detach_entities</code>.}}

	[[EB_RECYCLABLE]] recycling has another assisting function, it will automatically destroy [[EiffelVision2]] objects implementing [[EB_RECYCLABLE]]. <code>destroy</code> will only be called for the implementing [[EB_RECYCLABLE]] [[EiffelVision2]] object and not any of it's attributes, unless they are automatically recycled and implement [[EB_RECYCLABLE]] also.		[[https://svn.eiffel.com/eiffelstudio/trunk/Src/Eiffel/interface/new_graphical/managers/eb_recyclable.e\|EB_RECYCLABLE]] recycling has another assisting function, it will automatically destroy [[EiffelVision2]] objects implementing [[https://svn.eiffel.com/eiffelstudio/trunk/Src/Eiffel/interface/new_graphical/managers/eb_recyclable.e\|EB_RECYCLABLE]]. <code>destroy</code> will only be called for the implementing [[https://svn.eiffel.com/eiffelstudio/trunk/Src/Eiffel/interface/new_graphical/managers/eb_recyclable.e\|EB_RECYCLABLE]] [[EiffelVision2]] object and not any of it's attributes, unless they are automatically recycled and implement [[https://svn.eiffel.com/eiffelstudio/trunk/Src/Eiffel/interface/new_graphical/managers/eb_recyclable.e\|EB_RECYCLABLE]] also.

	=== Automatic Agent Removal ===		=== Automatic Agent Removal ===
	Agents are probably the number one cause of memory leaks inside EiffelStudio as they could be contained in a live object but references a recycled one. As the agent references a recycled object the GC retains the recycled object because there is still an active reference to it.		Agents are probably the number one cause of memory leaks inside EiffelStudio as they could be contained in a live object but references a recycled one. As the agent references a recycled object the GC retains the recycled object because there is still an active reference to it.

	[[EB_RECYCLABLE]] provides operations to facilitate here also. There are two routines to use when extending a sequence of actions and have the action automatically removed when the functioning object is recycled; <code>register_action</code> and <code>register_kamikaze_action</code>. <code>register_action</code> simply takes an [[ACTION_SEQUENCE]] and an action. It does the necessary extension to the action sequence and will prune the action when the object in which <code>register_action</code> was class is recycled. <code>register_kamikaze_action</code> performs in the same way as <code>register_action</code> does except that it extends the action sequence with the action to be called only once. Generally kamikaze actions are removed from the action sequence when the actions are called. However it is possible that the action sequence is never executed, after the kamikaze action has been added, so the action never pruned from the list of callees. This too can cause a memory leaks.		[[https://svn.eiffel.com/eiffelstudio/trunk/Src/Eiffel/interface/new_graphical/managers/eb_recyclable.e\|EB_RECYCLABLE]] provides operations to facilitate here also. There are two routines to use when extending a sequence of actions and have the action automatically removed when the functioning object is recycled; <code>register_action</code> and <code>register_kamikaze_action</code>. <code>register_action</code> simply takes an [[ACTION_SEQUENCE]] and an action. It does the necessary extension to the action sequence and will prune the action when the object in which <code>register_action</code> was class is recycled. <code>register_kamikaze_action</code> performs in the same way as <code>register_action</code> does except that it extends the action sequence with the action to be called only once. Generally kamikaze actions are removed from the action sequence when the actions are called. However it is possible that the action sequence is never executed, after the kamikaze action has been added, so the action never pruned from the list of callees. This too can cause a memory leaks.

	{{Warning\|<code>register_action</code> and <code>register_kamikaze_action</code> come in a basic, generic use form so they can be used with any action sequence. This does removed the static compile time analysis so be careful when using an agent with an action sequence that the open arguments match. Failure to do so will result in a segmentation violation at runtime.}}		{{Warning\|<code>register_action</code> and <code>register_kamikaze_action</code> come in a basic, generic use form so they can be used with any action sequence. This does removed the static compile time analysis so be careful when using an agent with an action sequence that the open arguments match. Failure to do so will result in a segmentation violation at runtime.}}

	=== No Magic Here ===		=== No Magic Here ===
	[[EB_RECYCLABLE]] is not a special class or is anyway known by the Eiffel compiler. That means unless <code>recycle</code> is called on an object implementing [[EB_RECYCLABLE]], it wont be recycled. For the time being [[EB_RECYCLABLE]] does not implement [[DISPOSABLE]] so the GC will be of no help.		[[https://svn.eiffel.com/eiffelstudio/trunk/Src/Eiffel/interface/new_graphical/managers/eb_recyclable.e\|EB_RECYCLABLE]] is not a special class or is anyway known by the Eiffel compiler. That means unless <code>recycle</code> is called on an object implementing [[https://svn.eiffel.com/eiffelstudio/trunk/Src/Eiffel/interface/new_graphical/managers/eb_recyclable.e\|EB_RECYCLABLE]], it wont be recycled. For the time being [[https://svn.eiffel.com/eiffelstudio/trunk/Src/Eiffel/interface/new_graphical/managers/eb_recyclable.e\|EB_RECYCLABLE]] does not implement [[http://freeelks.svn.sourceforge.net/viewvc/freeelks/trunk/library/kernel/disposable.e?view=markup\|DISPOSABLE]] so the GC will be of no help.

	The tool foundation implementation is [[EiffelStudio Foundations]] ([[ES_TOOL and ES_TOOL_PANEL]]) implement [[EB_RECYCLABLE]] and are automatically recycled when and as needed. However, this is one of the few cases. For example, the dialog foundation implementation in [[EiffelStudio Foundations]] ([[ES_DIALOG]]) '''does not''' call <code>recycle</code> automatically when close as a dialog may be reused. In that respect a dialog object should explicitly call <code>recycle</code> when no longer needed or to be automatically recycled by calling <code>auto_recycle</code>.		The tool foundation implementation is [[EiffelStudio Foundations]] ([[ES_TOOL and ES_TOOL_PANEL]]) implement [[https://svn.eiffel.com/eiffelstudio/trunk/Src/Eiffel/interface/new_graphical/managers/eb_recyclable.e\|EB_RECYCLABLE]] and are automatically recycled when and as needed. However, this is one of the few cases. For example, the dialog foundation implementation in [[EiffelStudio Foundations]] ([[ES_DIALOG]]) '''does not''' call <code>recycle</code> automatically when close as a dialog may be reused. In that respect a dialog object should explicitly call <code>recycle</code> when no longer needed or to be automatically recycled by calling <code>auto_recycle</code>.

	== Detecting Memory Leaks ==		== Detecting Memory Leaks ==
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	=== Locating Memory Leaks ===		=== Locating Memory Leaks ===
	After you have found a memory leak, it is time to drill down and find out where the leak is occurring. The Memory Tool has implicit knowledge of [[EB_RECYCLABLE]] and displays an object's recycled state. In the example image shown in the previous section <code>EB_DEVELOPMENT_WINDOW_AGENT</code> has two live instances in the object map. The first has not been recycled as it is in use by the first opened window. The second instance however has been recycled, and even so still leaves two references preventing the [[Garbage Collector\|garbage collector]] from reclaiming the object.		After you have found a memory leak, it is time to drill down and find out where the leak is occurring. The Memory Tool has implicit knowledge of [[https://svn.eiffel.com/eiffelstudio/trunk/Src/Eiffel/interface/new_graphical/managers/eb_recyclable.e\|EB_RECYCLABLE]] and displays an object's recycled state. In the example image shown in the previous section <code>EB_DEVELOPMENT_WINDOW_AGENT</code> has two live instances in the object map. The first has not been recycled as it is in use by the first opened window. The second instance however has been recycled, and even so still leaves two references preventing the [[Garbage Collector\|garbage collector]] from reclaiming the object.

	The problem lies in either or both of the <code>TUPLE [EB_DEVELOPMENT_WINDOW_AGENTS]</code> referrer instances. Expanding the referrer objects reveals their referrer objects and so on.		The problem lies in either or both of the <code>TUPLE [EB_DEVELOPMENT_WINDOW_AGENTS]</code> referrer instances. Expanding the referrer objects reveals their referrer objects and so on.
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	* In the debugger add a breakpoint on the first line of <code>ES_MEMORY_TOOL_PANEL.on_row_expanded</code>.		* In the debugger add a breakpoint on the first line of <code>ES_MEMORY_TOOL_PANEL.on_row_expanded</code>.
	* Now in the debugged version of [[EiffelStudio]] collapse the row (if it's not already) displaying the object of a [[PROCEDURE]], [[FUNCTION]] or [[PREDICATE]] type and then expanded it again.		* Now in the debugged version of [[EiffelStudio]] collapse the row (if it's not already) displaying the object of a [[http://freeelks.svn.sourceforge.net/viewvc/freeelks/trunk/library/kernel/procedure.e?view=markup\|PROCEDURE]], [[http://freeelks.svn.sourceforge.net/viewvc/freeelks/trunk/library/kernel/function.e?view=markup\|FUNCTION]] or [[http://freeelks.svn.sourceforge.net/viewvc/freeelks/trunk/library/kernel/predicate.e?view=markup\|PREDICATE]] type and then expanded it again.

	The debugger will now be broken into at the place breakpoint.		The debugger will now be broken into at the place breakpoint.
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	* In a debugger '''Watch Tool''' add the expression <code>a_row.data</code>.		* In a debugger '''Watch Tool''' add the expression <code>a_row.data</code>.
	* Expand the expression result and the debugger shows the name of the agent, which you can navigate to using pick and drop or the context menu.		* Expand the expression result and the debugger shows the name of the agent, which you can navigate to using pick and drop or the context menu.
	* Examine the callers of the agent and locate the area where it's added to an action sequence, or set on an object, and be sure to prune it from the action sequence or unset it in the object's <code>EB_RECYCLABLE.internal_recycle</code>. Alternatively you can use the [[User_Interface_Memory_Managment#Automatic Recycling\|automatic recycling]] facilities of [[EB_RECYCLABLE]] to register the agent.		* Examine the callers of the agent and locate the area where it's added to an action sequence, or set on an object, and be sure to prune it from the action sequence or unset it in the object's <code>EB_RECYCLABLE.internal_recycle</code>. Alternatively you can use the [[User_Interface_Memory_Managment#Automatic Recycling\|automatic recycling]] facilities of [[https://svn.eiffel.com/eiffelstudio/trunk/Src/Eiffel/interface/new_graphical/managers/eb_recyclable.e\|EB_RECYCLABLE]] to register the agent.

← Older revision		Revision as of 17:47, 31 October 2007
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	[[EiffelStudio]] has an in-built debug tool call the '''Memory Tool'''. It can be used to provide statistics on the current number of objects alive in [[EiffelStudio]] as well and show the difference between two queried sessions.		[[EiffelStudio]] has an in-built debug tool call the '''Memory Tool'''. It can be used to provide statistics on the current number of objects alive in [[EiffelStudio]] as well and show the difference between two queried sessions.

	The tool is to be used on the debugged version of EiffelStudio as it is a debug tool and not a debugging tool. To be a little cleared the tool shows the live view on the running process and not associated with the debugger.		The tool is to be used on the debugged version of EiffelStudio as it is a debug tool and not a debugging tool. To be a little cleared the tool shows the live view on the running process and is not associated with the debugger.

	=== Showing the Memory Tool ===		=== Showing the Memory Tool ===
	There are two ways to access the Memory Tool:		There are two ways to access the Memory Tool:
	* Press {{key\|CTRL}}+{{key\|ALT}}+{{key\|D}} to show the "debug" menu, which is shown as the [[EiffelStudio]] build number at the end of the main menu strip. From there you can select '''Show Memory Tool'''		* Press {{key\|CTRL}}+{{key\|ALT}}+{{key\|D}} to show the "debug" menu, which is shown as the [[EiffelStudio]] build number at the end of the main menu strip. From there you can select '''Show Memory Tool'''
	* If you have a project loaded hold {{key\|CTRL}} and ~~left mouse~~ click the ''Project Settings'' tool bar button.		* If you have a project loaded, hold {{key\|CTRL}} and click the ''Project Settings'' tool bar button.

	=== Catching Leaks ===		=== Catching Leaks ===
	In order to catch memory leaks you need to play spot the difference. Thankfully the tool does this for you between two snapshots of the live object map.		In order to catch memory leaks you need to play the game of spot the difference. Thankfully the tool does this for you between two selected snapshots of the process' live object map.

	Here is the process of beginning to detect a memory leak. It will display the ~~delta~~ of objects added and not removed between two snapshots:		Here is the process of beginning to detect a memory leak. It will display a delta representing the number of objects added and not removed between two taken snapshots:
	* Once [[EiffelStudio]] is shown, ~~display~~ the Memory Tool.		* Once the debugged [[EiffelStudio]] is shown, open the Memory Tool.
	* Click the '''Refresh''' button to display an initial view of the live object map running in that version of [[EiffelStudio]].		* Click the '''Refresh''' button to display an initial view of the live object map running in that version of [[EiffelStudio]].

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	* Now open a new window either using the '''File''' \| '''New Window''' menu item or pressing {{key\|CTRL}}+{{key\|N}}.		* Now open a new window either using the '''File''' \| '''New Window''' menu item or pressing {{key\|CTRL}}+{{key\|N}}.
	* Once opened show your tool or perform any interaction that instantiates classes you have integrated into [[EiffelStudio]].		* Once opened, show your tool or perform any interaction that instantiates classes you have integrated into [[EiffelStudio]].
	* Now close the new window and return back to the initial window with the Memory Tool.		* Now close the new window and return back to the initial window with the Memory Tool.
	* Click '''Refresh''' on the ~~tool~~ again. This will recalculate the live object map and display a delta result showing the number of new objects in memory.		* Click '''Refresh''' on the Memory Tool again. This will recalculate the live object map and display a delta result showing the number of new objects in memory.

	Here there is a leak. The delta is ''1'', where as it should be 0. This means that opening and closing a new window has leaked an instance of <code>EB_DEVELOPMENT_WINDOW_AGENTS</code>.		Here there is a leak! The delta is ''1'', where as it should be 0. This means that opening and closing a new window has leaked a single instance of <code>EB_DEVELOPMENT_WINDOW_AGENTS</code>.

	[[Image:Memory_tool_leak.png]]		[[Image:Memory_tool_leak.png]]

	A memory leak occurs when your tool or any of it's associated objects retains a reference to an internal part of EiffelStudio, indicated by a delta of 1 or more. When this happens there can actually be a lot of noise in the view. To reduce noise and home in on the problem area do the following:		A memory leak occurs when your tool or any of it's associated objects retains a reference to an internal part of EiffelStudio, indicated by a delta of 1 or more. When this happens there can actually be a lot of noise in the view as it in turn may reference many other objects. To reduce noise and home in on the problem area do the following:
	* Toggle the '''Delta Only''' button to on so only those results with positive deltas are shown.		* Toggle the '''Delta Only''' button to on so only those results with positive deltas are shown.
	* Enter a regular expression in the '''Type filter'''. For example, to show all EiffelStudio UI classes you would use: <code>^ES_\|^EB_</code>		* Enter a regular expression in the '''Type filter'''. For example, to show all EiffelStudio UI classes you would use: <code>^ES_\|^EB_</code>