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Add wxEventFilter and related functionality.

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Allow defining event filters to globally pre-process all application events
without having to override wxApp::FilterEvent().

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@69794 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
This commit is contained in:
Vadim Zeitlin
2011-11-22 13:18:50 +00:00
parent feb32e3165
commit 58cc15871d
18 changed files with 350 additions and 24 deletions
Download Patch File Download Diff File Expand all files Collapse all files

2
Makefile.in
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@@ -359,6 +359,7 @@ ALL_BASE_HEADERS = \
wx/dynload.h \
wx/encconv.h \
wx/event.h \
wx/eventfilter.h \
wx/evtloop.h \
wx/except.h \
wx/features.h \
@@ -537,6 +538,7 @@ ALL_PORTS_BASE_HEADERS = \
wx/dynload.h \
wx/encconv.h \
wx/event.h \
wx/eventfilter.h \
wx/evtloop.h \
wx/except.h \
wx/features.h \

1
build/bakefiles/files.bkl
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@@ -447,6 +447,7 @@ IMPORTANT: please read docs/tech/tn0016.txt before modifying this file!
wx/dynload.h
wx/encconv.h
wx/event.h
wx/eventfilter.h
wx/evtloop.h
wx/except.h
wx/features.h

4
build/msw/wx_base.dsp
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@@ -1231,6 +1231,10 @@ SOURCE=..\..\include\wx\event.h
# End Source File
# Begin Source File
SOURCE=..\..\include\wx\eventfilter.h
# End Source File
# Begin Source File
SOURCE=..\..\include\wx\evtloop.h
# End Source File
# Begin Source File

3
build/msw/wx_vc7_base.vcproj
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@@ -1347,6 +1347,9 @@
<File
RelativePath="..\..\include\wx\event.h">
</File>
<File
RelativePath="..\..\include\wx\eventfilter.h">
</File>
<File
RelativePath="..\..\include\wx\evtloop.h">
</File>

4
build/msw/wx_vc8_base.vcproj
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@@ -1817,6 +1817,10 @@
RelativePath="..\..\include\wx\event.h"
>
</File>
<File
RelativePath="..\..\include\wx\eventfilter.h"
>
</File>
<File
RelativePath="..\..\include\wx\evtloop.h"
>

4
build/msw/wx_vc9_base.vcproj
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@@ -1813,6 +1813,10 @@
RelativePath="..\..\include\wx\event.h"
>
</File>
<File
RelativePath="..\..\include\wx\eventfilter.h"
>
</File>
<File
RelativePath="..\..\include\wx\evtloop.h"
>

1
docs/changes.txt
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@@ -457,6 +457,7 @@ All:
- Fix parsing of negated long options in wxCmdLineParser (roed_bis).
- Fix crash in wxArray::insert() overload taking iterator range (wsu).
- Added wxEventFilter class and wxEvtHandler::{Add,Remove}Filter().
All (GUI):

13
include/wx/app.h
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@@ -18,6 +18,7 @@
// ----------------------------------------------------------------------------
#include "wx/event.h" // for the base class
#include "wx/eventfilter.h" // (and another one)
#include "wx/build.h"
#include "wx/cmdargs.h" // for wxCmdLineArgsArray used by wxApp::argv
#include "wx/init.h" // we must declare wxEntry()
@@ -70,7 +71,8 @@ extern WXDLLIMPEXP_DATA_BASE(wxList) wxPendingDelete;
// wxAppConsoleBase: wxApp for non-GUI applications
// ----------------------------------------------------------------------------
class WXDLLIMPEXP_BASE wxAppConsoleBase : public wxEvtHandler
class WXDLLIMPEXP_BASE wxAppConsoleBase : public wxEvtHandler,
public wxEventFilter
{
public:
// ctor and dtor
@@ -238,13 +240,8 @@ public:
// event processing functions
// --------------------------
// this method allows to filter all the events processed by the program, so
// you should try to return quickly from it to avoid slowing down the
// program to the crawl
//
// return value should be -1 to continue with the normal event processing,
// or TRUE or FALSE to stop further processing and pretend that the event
// had been already processed or won't be processed at all, respectively
// Implement the inherited wxEventFilter method but just return -1 from it
// to indicate that default processing should take place.
virtual int FilterEvent(wxEvent& event);
// return true if we're running event loop, i.e. if the events can

17
include/wx/event.h
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@@ -39,6 +39,7 @@
class WXDLLIMPEXP_FWD_BASE wxList;
class WXDLLIMPEXP_FWD_BASE wxEvent;
class WXDLLIMPEXP_FWD_BASE wxEventFilter;
#if wxUSE_GUI
class WXDLLIMPEXP_FWD_CORE wxDC;
class WXDLLIMPEXP_FWD_CORE wxMenu;
@@ -3013,6 +3014,19 @@ public:
bool IsUnlinked() const;
// Global event filters
// --------------------
// Add an event filter whose FilterEvent() method will be called for each
// and every event processed by wxWidgets. The filters are called in LIFO
// order and wxApp is registered as an event filter by default. The pointer
// must remain valid until it's removed with RemoveFilter() and is not
// deleted by wxEvtHandler.
static void AddFilter(wxEventFilter* filter);
// Remove a filter previously installed with AddFilter().
static void RemoveFilter(wxEventFilter* filter);
// Event queuing and processing
// ----------------------------
@@ -3360,6 +3374,9 @@ private:
// try to process events in all handlers chained to this one
bool DoTryChain(wxEvent& event);
// Head of the event filter linked list.
static wxEventFilter* ms_filterList;
DECLARE_DYNAMIC_CLASS_NO_COPY(wxEvtHandler)
};

72
include/wx/eventfilter.h Normal file
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@@ -0,0 +1,72 @@
///////////////////////////////////////////////////////////////////////////////
// Name: wx/eventfilter.h
// Purpose: wxEventFilter class declaration.
// Author: Vadim Zeitlin
// Created: 2011-11-21
// RCS-ID: $Id: wxhead.h,v 1.12 2010-04-22 12:44:51 zeitlin Exp $
// Copyright: (c) 2011 Vadim Zeitlin <vadim@wxwidgets.org>
// Licence: wxWindows licence
///////////////////////////////////////////////////////////////////////////////
#ifndef _WX_EVENTFILTER_H_
#define _WX_EVENTFILTER_H_
#include "wx/defs.h"
class WXDLLIMPEXP_FWD_BASE wxEvent;
class WXDLLIMPEXP_FWD_BASE wxEvtHandler;
// ----------------------------------------------------------------------------
// wxEventFilter is used with wxEvtHandler::AddFilter() and ProcessEvent().
// ----------------------------------------------------------------------------
class wxEventFilter
{
public:
// Possible return values for FilterEvent().
//
// Notice that the values of these enum elements are fixed due to backwards
// compatibility constraints.
enum
{
// Process event as usual.
Event_Skip = -1,
// Don't process the event normally at all.
Event_Ignore = 0,
// Event was already handled, don't process it normally.
Event_Processed = 1
};
wxEventFilter()
{
m_next = NULL;
}
virtual ~wxEventFilter()
{
wxASSERT_MSG( !m_next, "Forgot to call wxEvtHandler::RemoveFilter()?" );
}
// This method allows to filter all the events processed by the program, so
// you should try to return quickly from it to avoid slowing down the
// program to the crawl.
//
// Return value should be -1 to continue with the normal event processing,
// or true or false to stop further processing and pretend that the event
// had been already processed or won't be processed at all, respectively.
virtual int FilterEvent(wxEvent& event) = 0;
private:
// Objects of this class are made to be stored in a linked list in
// wxEvtHandler so put the next node ponter directly in the class itself.
wxEventFilter* m_next;
// And provide access to it for wxEvtHandler [only].
friend class wxEvtHandler;
wxDECLARE_NO_COPY_CLASS(wxEventFilter);
};
#endif // _WX_EVENTFILTER_H_

16
interface/wx/app.h
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@@ -37,7 +37,8 @@
@see @ref overview_app, wxApp, wxAppTraits, wxEventLoopBase
*/
class wxAppConsole : public wxEvtHandler
class wxAppConsole : public wxEvtHandler,
public wxEventFilter
{
protected:
/**
@@ -81,13 +82,14 @@ public:
virtual void ExitMainLoop();
/**
This function is called before processing any event and allows the application
to preempt the processing of some events.
Overridden wxEventFilter method.
If this method returns -1 the event is processed normally, otherwise either
@true or @false should be returned and the event processing stops immediately
considering that the event had been already processed (for the former return
value) or that it is not going to be processed at all (for the latter one).
This function is called before processing any event and allows the application
to preempt the processing of some events, see wxEventFilter
documentation for more information.
wxApp implementation of this method always return -1 indicating that
the event should be processed normally.
*/
virtual int FilterEvent(wxEvent& event);

34
interface/wx/event.h
View File

@@ -1088,6 +1088,40 @@ public:
//@}
/**
@name Global event filters.
Methods for working with the global list of event filters.
Event filters can be defined to pre-process all the events that happen
in an application, see wxEventFilter documentation for more information.
*/
//@{
/**
Add an event filter whose FilterEvent() method will be called for each
and every event processed by wxWidgets.
The filters are called in LIFO order and wxApp is registered as an
event filter by default. The pointer must remain valid until it's
removed with RemoveFilter() and is not deleted by wxEvtHandler.
@since 2.9.3
*/
static void AddFilter(wxEventFilter* filter);
/**
Remove a filter previously installed with AddFilter().
It's an error to remove a filter that hadn't been previously added or
was already removed.
@since 2.9.3
*/
static void RemoveFilter(wxEventFilter* filter);
//@}
protected:
/**
Method called by ProcessEvent() before examining this object event

139
interface/wx/eventfilter.h Normal file
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@@ -0,0 +1,139 @@
///////////////////////////////////////////////////////////////////////////////
// Name: interface/wx/eventfilter.h
// Purpose: wxEventFilter class documentation
// Author: Vadim Zeitlin
// Created: 2011-11-21
// RCS-ID: $Id$
// Copyright: (c) 2011 Vadim Zeitlin <vadim@wxwidgets.org>
// Licence: wxWindows licence
///////////////////////////////////////////////////////////////////////////////
/**
A global event filter for pre-processing all the events generated in the
program.
This is a very simple class which just provides FilterEvent() virtual
method to be called by wxEvtHandler before starting process of any event.
Thus, inheriting from this class and overriding FilterEvent() allows to
capture and possibly handle or ignore all the events happening in the
program. Of course, having event filters adds additional overhead to every
event processing and so should not be used lightly and your FilterEvent()
code should try to return as quickly as possible, especially for the events
it is not interested in.
An example of using this class:
@code
// This class allows to determine the last time the user has worked with
// this application:
class LastActivityTimeDetector : public wxEventFilter
{
public:
LastActivityTimeDetector()
{
wxEvtHandler::AddFilter(this);
m_last = wxDateTime::Now();
}
virtual ~LastActivityTimeDetector()
{
wxEvtHandler::RemoveFilter(this);
}
virtual int FilterEvent(wxEvent& event)
{
// Update the last user activity
const wxEventType t = event.GetEventType();
if ( t == wxEVT_KEY_DOWN || t == wxEVT_MOTION ||
t == wxEVT_LEFT_DOWN ||
t == wxEVT_RIGHT_DOWN ||
t == wxEVT_MIDDLE_DOWN )
{
m_last = wxDateTime::Now();
}
// Continue processing the event normally as well.
return Event_Skip;
}
// This function could be called periodically from some timer to
// do something (e.g. hide sensitive data or log out from remote
// server) if the user has been inactive for some time period.
bool IsInactiveFor(const wxTimeSpan& diff) const
{
return wxDateTime::Now() - diff > m_last;
}
private:
wxDateTime m_last;
};
@endcode
Notice that wxApp derives from wxEventFilter and is registered as an event
filter during its creation so you may also override FilterEvent() method in
your wxApp-derived class and, in fact, this is often the most convenient
way to do it. However creating a new class deriving directly from
wxEventFilter allows to isolate the event filtering code in its own
separate class and also to have several independent filters, if necessary.
@category{events}
@since 2.9.3
*/
class wxEventFilter
{
public:
/// Possible return values for FilterEvent().
enum
{
/// Process event as usual.
Event_Skip = -1,
/// Don't process the event normally at all.
Event_Ignore = 0,
/// Event was already handled, don't process it normally.
Event_Processed = 1
};
/**
Default constructor.
Constructor does not register this filter using
wxEvtHandler::AddFilter(), it's your responsibility to do it when
necessary.
Notice that the objects of this class can't be copied.
*/
wxEventFilter();
/**
Destructor.
You must call wxEvtHandler::RemoveFilter() before destroying this
object (possibly from the derived class destructor), failure to do this
is indicated by an assert unless assertions are disabled.
*/
virtual ~wxEventFilter();
/**
Override this method to implement event pre-processing.
This method allows to filter all the events processed by the program,
so you should try to return quickly from it to avoid slowing down the
program to the crawl.
Although the return type of this method is @c int, this is only due to
backwards compatibility concerns and the actual return value must be
one of the @c Event_XXX constants defined above:
- Event_Skip to continue processing the event normally (this should
be used in most cases).
- Event_Ignore to not process this event at all (this can be used
to suppress some events).
- Event_Processed to not process this event normally but indicate
that it was already processed by the event filter and so no default
processing should take place neither (this should only be used if
the filter really did process the event).
*/
virtual int FilterEvent(wxEvent& event) = 0;
};

6
src/common/appbase.cpp
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@@ -150,10 +150,14 @@ wxAppConsoleBase::wxAppConsoleBase()
wxDELETE(m_traits);
#endif
#endif
wxEvtHandler::AddFilter(this);
}
wxAppConsoleBase::~wxAppConsoleBase()
{
wxEvtHandler::RemoveFilter(this);
// we're being destroyed and using this object from now on may not work or
// even crash so don't leave dangling pointers to it
ms_appInstance = NULL;
@@ -401,7 +405,7 @@ bool wxAppConsoleBase::IsMainLoopRunning()
int wxAppConsoleBase::FilterEvent(wxEvent& WXUNUSED(event))
{
// process the events normally by default
return -1;
return Event_Skip;
}
void wxAppConsoleBase::DelayPendingEventHandler(wxEvtHandler* toDelay)

55
src/common/event.cpp
View File

@@ -25,6 +25,7 @@
#endif
#include "wx/event.h"
#include "wx/eventfilter.h"
#include "wx/evtloop.h"
#ifndef WX_PRECOMP
@@ -1132,6 +1133,43 @@ bool wxEvtHandler::IsUnlinked() const
m_nextHandler == NULL;
}
wxEventFilter* wxEvtHandler::ms_filterList = NULL;
/* static */ void wxEvtHandler::AddFilter(wxEventFilter* filter)
{
wxCHECK_RET( filter, "NULL filter" );
filter->m_next = ms_filterList;
ms_filterList = filter;
}
/* static */ void wxEvtHandler::RemoveFilter(wxEventFilter* filter)
{
wxEventFilter* prev = NULL;
for ( wxEventFilter* f = ms_filterList; f; f = f->m_next )
{
if ( f == filter )
{
// Set the previous list element or the list head to the next
// element.
if ( prev )
prev->m_next = f->m_next;
else
ms_filterList = f->m_next;
// Also reset the next pointer in the filter itself just to avoid
// having possibly dangling pointers, even though it's not strictly
// necessary.
f->m_next = NULL;
// Skip the assert below.
return;
}
}
wxFAIL_MSG( "Filter not found" );
}
#if wxUSE_THREADS
bool wxEvtHandler::ProcessThreadEvent(const wxEvent& event)
@@ -1360,23 +1398,24 @@ bool wxEvtHandler::TryAfter(wxEvent& event)
bool wxEvtHandler::ProcessEvent(wxEvent& event)
{
// The very first thing we do is to allow the application to hook into
// event processing in order to globally pre-process all events.
// The very first thing we do is to allow any registered filters to hook
// into event processing in order to globally pre-process all events.
//
// Note that we should only do it if we're the first event handler called
// to avoid calling FilterEvent() multiple times as the event goes through
// the event handler chain and possibly upwards the window hierarchy.
if ( !event.WasProcessed() )
{
if ( wxTheApp )
for ( wxEventFilter* f = ms_filterList; f; f = f->m_next )
{
int rc = wxTheApp->FilterEvent(event);
if ( rc != -1 )
int rc = f->FilterEvent(event);
if ( rc != wxEventFilter::Event_Skip )
{
wxASSERT_MSG( rc == 1 || rc == 0,
"unexpected wxApp::FilterEvent return value" );
wxASSERT_MSG( rc == wxEventFilter::Event_Ignore ||
rc == wxEventFilter::Event_Processed,
"unexpected FilterEvent() return value" );
return rc != 0;
return rc != wxEventFilter::Event_Ignore;
}
//else: proceed normally
}

1
wxGTK.spec
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@@ -226,6 +226,7 @@ wx/dynlib.h
wx/dynload.h
wx/encconv.h
wx/event.h
wx/eventfilter.h
wx/evtloop.h
wx/except.h
wx/features.h

1
wxMotif.spec
View File

@@ -128,6 +128,7 @@ wx/dynlib.h
wx/dynload.h
wx/encconv.h
wx/event.h
wx/eventfilter.h
wx/evtloop.h
wx/except.h
wx/features.h

1
wxX11.spec
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@@ -152,6 +152,7 @@ wx/dynlib.h
wx/dynload.h
wx/encconv.h
wx/event.h
wx/eventfilter.h
wx/evtloop.h
wx/except.h
wx/features.h