Package RASCAL.DragNDrop

Description	Event definitions for handling the Drag'N'Drop protocol (datasave and dataload). Includes a stack implementation for handling multiple dataloads.
Author	bbracke
Date	2005/11/21 20:14:33
Revision	1.1

Clauses

Quick access : Clauses - Generics - Definitions - Subprograms

Context clauses
Ada.Strings.Unbounded
Interfaces.C
RASCAL.OS

Use clauses
Ada.Strings.Unbounded
Interfaces.C
RASCAL.OS

Definitions

Quick access : Clauses - Generics - Definitions - Subprograms

Types
*Name*	*Declaration*
Message_DataSave_Pointer	access Message_DataSave
Message_DataSaveAck_Pointer	access Message_DataSaveAck
Message_DataLoad_Pointer	access Message_DataLoad
Message_DataLoadAck_Pointer	access Message_DataLoadAck
Message_DataOpen_Pointer	access Message_DataOpen
Message_DataSaved_Pointer	access Message_DataSaved
Message_RamFetch_Pointer	access Message_RamFetch
Message_RamTransmit_Pointer	access Message_RamTransmit

Message_DataSave	record
This indicates that the sender wants to save data to the receiver. Normal use Ź\t User has terminated a drag Ź\t You get the first four words with Wimp_GetPointerInfo. Ź\t You send message to mentioned window. Possible responses from other task Ź\t It sends DataSaveAck Ź\t It sends RamFetch You should store the my_ref of each data save message, to check against any future DataSaved message you might receive.
*Component*	*Type*	*Default*
Leaf_Name	Char_Array (1..208)
File_Type	Integer
Size	Integer
Screen_Y	Integer
Screen_X	Integer
Icon	Icon_Handle_Type
Window	Wimp_Handle_Type
Header	Message_Event_Header

AMEL_Message_DataSave	abstract tagged record
inheritance from	Message_EventListener (Message_Event_DataSave)
*Component*	*Type*	*Default*
Event	Message_DataSave_Pointer

Message_DataSaveAck	record
Icon nr, and screen x,y are preserved from the DataSave message. This is usually followed by a DataLoad message.
*Component*	*Type*	*Default*
Full_Path	Char_Array (1..208)
File_Type	Integer
Size	Integer
Screen_Y	Integer
Screen_X	Integer
Icon	Icon_Handle_Type
Window	Wimp_Handle_Type
Header	Message_Event_Header

AMEL_Message_DataSaveAck	abstract tagged record
inheritance from	Message_EventListener (Message_Event_DataSaveAck)
*Component*	*Type*	*Default*
Event	Message_DataSaveAck_Pointer

Message_DataLoad	record
Receiver of message should load, and answer with DataLoadAck if successfull. The column and row information is not present in RISC OS 2.
*Component*	*Type*	*Default*
Row	Integer
Column	Integer
Full_Path	Char_Array (1..200)
File_Type	Integer
Size	Integer
Screen_Y	Integer
Screen_X	Integer
Icon	Icon_Handle_Type
Window	Wimp_Handle_Type
Header	Message_Event_Header

AMEL_Message_DataLoad	abstract tagged record
inheritance from	Message_EventListener (Message_Event_DataLoad)
*Component*	*Type*	*Default*
Event	Message_DataLoad_Pointer

Message_DataLoadAck	record
This is sent as an answer to a DataLoad message. All that should be done, is to change message type to 4 (DataLoadAck), and fill in the your_ref field.
*Component*	*Type*	*Default*
Full_Path	Char_Array (1..208)
File_Type	Integer
Size	Integer
Screen_Y	Integer
Screen_X	Integer
Icon	Icon_Handle_Type
Window	Wimp_Handle_Type
Header	Message_Event_Header

AMEL_Message_DataLoadAck	abstract tagged record
inheritance from	Message_EventListener (Message_Event_DataLoadAck)
*Component*	*Type*	*Default*
Event	Message_DataLoadAck_Pointer

Message_DataOpen	record
This message is broadcasted when the user doubleclicks on a file. If the receiver wants to load the file, he should acknowledge this message by returning a DataLoadAck message. If no one acknowledges the message, the filer will try to run It.
*Component*	*Type*	*Default*
Full_Path	Char_Array (1..208)
File_Type	Integer
Zero	Integer
Y_Offset	Integer
X_Offset	Integer
Unused	Integer
Window	Wimp_Handle_Type
Header	Message_Event_Header

AMEL_Message_DataOpen	abstract tagged record
inheritance from	Message_EventListener (Message_Event_DataOpen)
*Component*	*Type*	*Default*
Event	Message_DataOpen_Pointer

Message_DataSaved	record
This message is sent back to the originator of a saved file if at some later time it becomes "safe" (i.e. on disc). You should compare the your_ref in this message with the my_ref you stored when you sent the original DataSave message. If they tally the file can now be marked as safe, unless the user had edited it in the meantime. Probably the best implementation is for your program to store the my_ref with the file, but zero it on any modification, as 0 will not be a valid your_ref. It appears that this message is designed for cases where one program saves a file to another program, and then that second program saves the unmodified file to disc.
*Component*	*Type*	*Default*
Header	Message_Event_Header

AMEL_Message_DataSaved	abstract tagged record
inheritance from	Message_EventListener (Message_Event_DataSaved)
*Component*	*Type*	*Default*
Event	Message_DataSaved_Pointer

Message_RamFetch	record
*Component*	*Type*	*Default*
Buffer_Size	Integer
Buffer_Pointer	Integer
Header	Message_Event_Header

AMEL_Message_RamFetch	abstract tagged record
inheritance from	Message_EventListener (Message_Event_RamFetch)
*Component*	*Type*	*Default*
Event	Message_RamFetch_Pointer

Message_RamTransmit	record
After receiving a RamFetch message, you write data to buffer, using Wimp_TransferBlock, and then send back this message.
*Component*	*Type*	*Default*
Amount_Used	Integer
Buffer_Pointer	Integer
Header	Message_Event_Header

AMEL_Message_RamTransmit	abstract tagged record
inheritance from	Message_EventListener (Message_Event_RamTransmit)
*Component*	*Type*	*Default*
Event	Message_RamTransmit_Pointer

Pragmas
Convention	(C, Message_DataSave)
Convention	(C, Message_DataSaveAck)
Convention	(C, Message_DataLoad)
Convention	(C, Message_DataLoadAck)
Convention	(C, Message_DataOpen)
Convention	(C, Message_DataSaved)
Convention	(C, Message_RamFetch)
Convention	(C, Message_RamTransmit)

Subprograms

Quick access : Clauses - Generics - Definitions - Subprograms

Empty	function
*Return*	boolean
Is the stack empty ?

Push_DragObject	procedure
Add a new DragNDrop object to the stack.

*Parameter name*	*Type*	*Mode*	*Default*
Path	Unbounded_String	in
Window	Wimp_Handle_Type	in	0
Icon	Icon_Handle_Type	in	0

Pop_DragObject	procedure
Return data of first drag object in the stack and removes that element from the stack.

*Parameter name*	*Type*	*Mode*	*Default*
Path	Unbounded_String	out
Window	Wimp_Handle_Type	out
Icon	Icon_Handle_Type	out