Class: RubyCurses::AbstractUndo

Inherits:
Object
  • Object
show all
Defined in:
lib/rbcurse/experimental/widgets/undomanager.rb

Overview

AbstractUndo has the basic workings of the undo redo facility. It leaves the actual undo and redo to the implementing source object. However, it does the work of storing edits, and passing the correct edit to the implementor when the source object calls for an undo or redo operation. It thus manages the edit (undo) queue.

Direct Known Subclasses

SimpleUndo

Instance Method Summary collapse

Constructor Details

#initialize(_source) ⇒ AbstractUndo

initialize the source object which will issue undo requests



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# File 'lib/rbcurse/experimental/widgets/undomanager.rb', line 32

def initialize _source
  source(_source) #if _source
  @pointer = 0
  @actions = []
  $log.debug " INSIDE UNDO CONSTR "
end

Instance Method Details

#add_edit(event) ⇒ Object

this is called whenever an undoable edit has happened. Currently, it is linked above in the bind statement. We’ve attached this method as a listener to the source.



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# File 'lib/rbcurse/experimental/widgets/undomanager.rb', line 51

def add_edit event
  # this debug is very specific. it should be removed later. We do not know about the object
  $log.debug " UNDO GOT #{event}: #{event.type}, (#{event.text}), rej: #{@reject_update}  "
  return if @reject_update
  if @pointer < @actions.length
    $log.debug " removing some actions since #{@pointer} < #{@actions.length} "
    @actions.slice!(@pointer..-1)
    $log.debug " removed actions since #{@pointer} , #{@actions.length} "
  end
  @actions << event
  @pointer = @actions.length
end

#perform_redo(edit) ⇒ Object 



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# File 'lib/rbcurse/experimental/widgets/undomanager.rb', line 91

def perform_redo edit
  raise "You must implement this for your undoable component "
end

#perform_undo(edit) ⇒ Object 



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# File 'lib/rbcurse/experimental/widgets/undomanager.rb', line 94

def perform_undo edit
  raise "You must implement this for your undoable component "
  # to be implemented
end

#redo ⇒ Object

this has to be bound in source typically bind C-r to redo() this method figures out the correct redo object to be sent to the implementor



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# File 'lib/rbcurse/experimental/widgets/undomanager.rb', line 81

def redo
  $log.debug "UNDO GOT REDO call #{@pointer}, #{@actions.size}  "
  return if @pointer >= @actions.size
  @reject_update = true
  edit = @actions[@pointer]
  perform_redo edit
  @source.repaint_required true
  @pointer +=1 #if @pointer > 0
  @reject_update = false
end

#source(_source) ⇒ Object 



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# File 'lib/rbcurse/experimental/widgets/undomanager.rb', line 38

def source(_source)
  $log.debug " calling source= "
  raise "Cannot pass a nil source" unless _source
  @source = _source
  # currently this is very hardcode again. we need to see this in the light of other objects
  #@source.bind(:CHANGE){|eve| add_edit(eve) }
  # a little roundabout but done for getting things up fast
  @source.undo_handler(self)
  $log.debug " I am listening to change events on #{@source.name} "
end

#undo ⇒ Object

this has to be bound in source component typically bind C-_ to undo() this method figures out the correct undo object to be sent to the implementor



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# File 'lib/rbcurse/experimental/widgets/undomanager.rb', line 67

def undo
  $log.debug " got UNDO call #{@pointer}, sz:#{@actions.size}  "
  return if @pointer == 0
  @reject_update = true
  @pointer -=1 #if @pointer > 0
  @source.repaint_required true
  @reject_update = false
  edit = @actions[@pointer]
  perform_undo edit
end