-- File: MBQueue.mesa
-- Interface: Provides Menu items and Buttons that are automatically serialized
-- Created by: Cattell and Haugeland on October 21, 1982 9:11 am
-- Last edited by:
  -- Cattell on October 21, 1982 9:11 am
  -- MBrown on October 21, 1982 6:22 pm
-- Last Edited by: Maxwell, December 17, 1982 10:06 am
-- Last Edited by: McGregor, July 21, 1983 10:55 am

DIRECTORY
  Buttons USING [Button, ButtonProc],
  Menus USING [ClickProc, MenuEntry, MouseButton],
  Rope USING [ROPE],
  ViewerClasses USING [ViewerRec],
  VFonts USING [Font, defaultFont];

MBQueue: CEDAR DEFINITIONS
  IMPORTS VFonts =

BEGIN

Queue: TYPE = REF QueueObj;
QueueObj: TYPE;

Create: PROC [pushModel: BOOL _ TRUE] RETURNS [Queue];
  -- Creates a queue, a context in which mouse buttons are serialized.  All menu item and
  -- mouse button procs defined in the context of this queue will be strictly serialized, i.e.
  -- the procs will be called in the order that the user clicked, and each proc will completely
  -- finish execution before the next one starts.
  -- If pushModel = FALSE, then actions are to be removed from the queue by a client process,
  -- using DequeueAction (below), rather than by this package.
  -- The client process should be prepared to handle ABORTED. 


CreateMenuEntry: PROC [
   q: Queue, name: Rope.ROPE, proc: Menus.ClickProc, clientData: REF ANY _ NIL,
    documentation: REF ANY _ NIL, fork: BOOL _ TRUE, guarded: BOOL _ FALSE]
    RETURNS [Menus.MenuEntry];
    -- Identical to Menus.CreateEntry, except for the first argument q.  Defines a menu item that
    -- is interpreted in the context of q.

CreateButton: PROC [
   q: Queue, info: ViewerClasses.ViewerRec _ [],
   proc: Buttons.ButtonProc, clientData: REF ANY _ NIL,
    fork: BOOL _ TRUE, font: VFonts.Font _ VFonts.defaultFont, documentation: REF ANY _ NIL,
    guarded: BOOL _ FALSE, paint: BOOL _ TRUE ] RETURNS [Buttons.Button];
    -- Identical to Buttons.Create, except for the first argument q.  Defines a button that
    -- is interpreted in the context of q.
    
QueueClientAction: PROC [
   q: Queue, proc: PROC [REF ANY], data: REF ANY];
   -- Allows client to queue actions other than the menu item clicks and button clicks, which
   -- are user-initiated.  The client's proc will be called after any user clicks before the call,
   -- and before any user clicks after the call.

Action: TYPE = RECORD [
  SELECT type: * FROM 
    client => [
      proc: PROC [REF ANY],
      data: REF ANY ],
    user => [
      proc: Menus.ClickProc,
      parent: REF ANY, clientData: REF ANY,
      mouseButton: Menus.MouseButton, shift, control: BOOL ]
    ENDCASE
    ];

DequeueAction: PROC [q: Queue] RETURNS [Action];
   -- Waits for an action to appear, then returns it.
   -- Called only for "pull model" queues.

Flush: PROC [q: Queue];
  -- Flushes all pending button presses and menu selections in the context of q.  This procedure
  -- can be called, e.g., when some illegal actions suggests the user is confused an further
  -- mouse-ahead should be ignored.


END.