Implementation of the Handler Chain functions, HandlerChain_SendMessage(), HandlerChain_AddWindow(), HandlerChain_RemoveWindow(), and HandlerChain_ToString(), as used in the HandlerChain Pattern. More...

#include <stdlib.h>
#include <stdio.h>
#include <stdbool.h>
#include "helpers/mutex.h"
#include "helpers/uintarray.h"
#include "HandlerChain_MessageWindow.h"
#include "HandlerChain_HandlerFunctions.h"

Include dependency graph for HandlerChain_HandlerFunctions.c:

Go to the source code of this file.

Functions
static void	_DestroyMutex (void)
	An atexit() handler to destroy the mutex on program exit.

static bool	_CreateMutex (void)
	Helper function to create the mutex, if not already created.

static void	_LockMutex (void)
	Helper function to lock the mutex.

static void	_UnlockMutex (void)
	Helper function to unlock the mutex.

void	HandlerChain_SendMessage (int windowId, Message *message)
	Send a message to each of the handlers in the list, protected by a multi-threading lock.

bool	HandlerChain_AddWindow (int windowId)
	Add an instance of a MessageWindow to end of the list of windows, protected by a multi-threading lock.

void	HandlerChain_RemoveWindow (int windowId)
	Remove an instance of a MessageWindow from the list, protected by a multi-threading lock.

bool	HandlerChain_ToString (DynamicString *output)
	Convert the Handler Chain to a string, protected by a multi-threading lock.

Variables
static Mutex	_mutex
	A mutex used to protect the handler list from cross-thread corruption.

static bool	_mutex_initialized = false
	A flag to indicate whether the mutex has been initialized and is ready for use.

static UIntArray	_handleList = { 0 }
	List of IDs of MessageWindow objects that can be sent messages.

Detailed Description

Implementation of the Handler Chain functions, HandlerChain_SendMessage(), HandlerChain_AddWindow(), HandlerChain_RemoveWindow(), and HandlerChain_ToString(), as used in the HandlerChain Pattern.

Definition in file HandlerChain_HandlerFunctions.c.

Function Documentation

◆ _CreateMutex()

static bool _CreateMutex ( void )

static

Helper function to create the mutex, if not already created.

Returns: Returns true if the mutex was created or already exists; otherwise, returns false, the mutex is not usable.

Definition at line 51 of file HandlerChain_HandlerFunctions.c.

References _DestroyMutex(), _mutex, _mutex_initialized, and mutex_create().

Referenced by _LockMutex(), and _UnlockMutex().

◆ _DestroyMutex()

static void _DestroyMutex ( void )

static

An atexit() handler to destroy the mutex on program exit.

Definition at line 37 of file HandlerChain_HandlerFunctions.c.

References _mutex, _mutex_initialized, and mutex_destroy().

Referenced by _CreateMutex().

◆ _LockMutex()

static void _LockMutex ( void )

static

Helper function to lock the mutex.

Definition at line 67 of file HandlerChain_HandlerFunctions.c.

References _CreateMutex(), _mutex, and mutex_lock().

Referenced by HandlerChain_AddWindow(), HandlerChain_RemoveWindow(), HandlerChain_SendMessage(), and HandlerChain_ToString().

◆ _UnlockMutex()

static void _UnlockMutex ( void )

static

Helper function to unlock the mutex.

Definition at line 78 of file HandlerChain_HandlerFunctions.c.

References _CreateMutex(), _mutex, and mutex_unlock().

Referenced by HandlerChain_AddWindow(), HandlerChain_RemoveWindow(), HandlerChain_SendMessage(), and HandlerChain_ToString().

◆ HandlerChain_AddWindow()

bool HandlerChain_AddWindow ( int windowId )

Add an instance of a MessageWindow to end of the list of windows, protected by a multi-threading lock.

If a MessageWindow is already in the list, it is not added again.

Parameters

windowId ID of the MessageWindow to add.

Returns: Returns true if the handler chain was successfully added to the list; otherwise, returns false, indicating an out of memory condition (or a NULL argument).

Definition at line 136 of file HandlerChain_HandlerFunctions.c.

References _handleList, _LockMutex(), _UnlockMutex(), UIntArray_AddInt(), and UIntArray_Find().

Referenced by MessageWindow_Create().

◆ HandlerChain_RemoveWindow()

void HandlerChain_RemoveWindow ( int windowId )

Remove an instance of a MessageWindow from the list, protected by a multi-threading lock.

If the MessageWindow is not in the list, the request to remove is ignored.

Parameters

windowId ID of the MessageWindow to remove.

Definition at line 162 of file HandlerChain_HandlerFunctions.c.

References _handleList, _LockMutex(), _UnlockMutex(), UIntArray_Find(), and UIntArray_RemoveInt().

Referenced by _HandleDestroyMessage().

◆ HandlerChain_SendMessage()

void HandlerChain_SendMessage	(	int	windowId,
		Message *	message
	)

Send a message to each of the handlers in the list, protected by a multi-threading lock.

Parameters

windowId	ID of window to target message with. -1 to target all windows.
message	The Message object to send to each handler.

Definition at line 105 of file HandlerChain_HandlerFunctions.c.

References _handleList, _LockMutex(), _UnlockMutex(), UIntArray::data, UIntArray::length, MessageWindow_ProcessMessage(), UIntArray_Clear(), and UIntArray_Copy().

Referenced by _HandleButtonUpMessage(), _HandleChain_DestroyWindows(), _HandleCloseMessage(), and HandlerChain_Exercise().

◆ HandlerChain_ToString()

bool HandlerChain_ToString ( DynamicString * output )

Convert the Handler Chain to a string, protected by a multi-threading lock.

Parameters

output Returns a string representation of the Handler Chain and all the handlers it contains.

Returns: Returns true if the handler chain was successfully converted to a string; otherwise, returns false, indicating an out of memory condition (or a NULL argument).

Definition at line 176 of file HandlerChain_HandlerFunctions.c.

References _handleList, _LockMutex(), _UnlockMutex(), UIntArray::data, DynamicString_Append(), DynamicString_Clear(), UIntArray::length, MessageWindow_ToString(), DynamicString::string, UIntArray_Clear(), and UIntArray_Copy().