sup

lib/sup/modes/line_cursor_mode.rb (4970B) - raw

 module Redwood
 
 ## extends ScrollMode to have a line-based cursor.
 class LineCursorMode < ScrollMode
   register_keymap do |k|
     ## overwrite scrollmode binding on arrow keys for cursor movement
     ## but j and k still scroll!
     k.add :cursor_down, "Move cursor down one line", :down, 'j'
     k.add :cursor_up, "Move cursor up one line", :up, 'k'
     k.add :select, "Select this item", :enter
   end
 
   attr_reader :curpos
 
   def initialize opts={}
     @cursor_top = @curpos = opts.delete(:skip_top_rows) || 0
     @load_more_callbacks = []
     @load_more_q = Queue.new
     @load_more_thread = ::Thread.new do
       while true
         e = @load_more_q.pop
         @load_more_callbacks.each { |c| c.call e }
         hysteresis = $config[:load_more_threads_hysteresis] || 0.5
         if hysteresis > 0 then
           sleep hysteresis
           @load_more_q.pop until @load_more_q.empty?
         end
       end
     end
 
     super opts
   end
 
   def spawned; call_load_more_callbacks buffer.content_height + 1; end
 
   def cleanup
     @load_more_thread.kill
     super
   end
 
   def draw
     super
     set_status
   end
 
 protected
 
   ## callbacks when the cursor is asked to go beyond the bottom
   def to_load_more &b
     @load_more_callbacks << b
   end
 
   def draw_line ln, opts={}
     if ln == @curpos
       super ln, :highlight => true, :debug => opts[:debug], :color => :text_color
     else
       super ln, :color => :text_color
     end
   end
 
   def ensure_mode_validity
     super
     raise @curpos.inspect unless @curpos.is_a?(Integer)
     c = @curpos.clamp topline, botline - 1
     c = @cursor_top if c < @cursor_top
     buffer.mark_dirty unless c == @curpos
     @curpos = c
   end
 
   def set_cursor_pos p
     return if @curpos == p
     @curpos = p.clamp @cursor_top, lines
     buffer.mark_dirty if buffer # not sure why the buffer is gone
     set_status
   end
 
   ## override search behavior to be cursor-based. this is a stupid
   ## implementation and should be made better. TODO: improve.
   def search_goto_line line
     page_down while line >= botline
     page_up while line < topline
     set_cursor_pos line
   end
 
   def search_start_line; @curpos end
 
   def line_down # overwrite scrollmode
     super
     call_load_more_callbacks([topline + buffer.content_height - lines, 10].max) if topline + buffer.content_height > lines
     set_cursor_pos topline if @curpos < topline
   end
 
   def line_up # overwrite scrollmode
     super
     set_cursor_pos botline - 1 if @curpos > botline - 1
   end
 
   def cursor_down
     call_load_more_callbacks buffer.content_height if @curpos >= lines - [buffer.content_height/2,1].max
     return false unless @curpos < lines - 1
 
     if $config[:continuous_scroll] and (@curpos == botline - 3 and @curpos < lines - 3)
       # load more lines, one at a time.
       jump_to_line topline + 1
       @curpos += 1
       unless buffer.dirty?
         draw_line @curpos - 1
         draw_line @curpos
         set_status
         buffer.commit
       end
     elsif @curpos >= botline - 1
       page_down
       set_cursor_pos topline
     else
       @curpos += 1
       unless buffer.dirty?
         draw_line @curpos - 1
         draw_line @curpos
         set_status
         buffer.commit
       end
     end
     true
   end
 
   def cursor_up
     return false unless @curpos > @cursor_top
 
     if $config[:continuous_scroll] and (@curpos == topline + 2)
       jump_to_line topline - 1
       @curpos -= 1
       unless buffer.dirty?
         draw_line @curpos + 1
         draw_line @curpos
         set_status
         buffer.commit
       end
     elsif @curpos == topline
       old_topline = topline
       page_up
       set_cursor_pos [old_topline - 1, topline].max
     else
       @curpos -= 1
       unless buffer.dirty?
         draw_line @curpos + 1
         draw_line @curpos
         set_status
         buffer.commit
       end
     end
     true
   end
 
   def page_up # overwrite
     if topline <= @cursor_top
       set_cursor_pos @cursor_top
     else
       relpos = @curpos - topline
       super
       set_cursor_pos topline + relpos
     end
   end
 
   def half_page_up
     super
     set_cursor_pos [botline, @curpos].min
   end
 
   def page_down
     relpos = @curpos - topline
     super
     set_cursor_pos [topline + relpos, lines - 1].min
     call_load_more_callbacks buffer.content_height if lines < topline + buffer.content_height
   end
 
   def half_page_down
     super
     set_cursor_pos [topline, @curpos].max
     call_load_more_callbacks buffer.content_height if lines < topline + buffer.content_height
   end
 
   def jump_to_start
     super
     set_cursor_pos @cursor_top
   end
 
   def jump_to_end
     super if topline < (lines - buffer.content_height)
     set_cursor_pos(lines - 1)
     call_load_more_callbacks buffer.content_height
   end
 
 private
 
   def set_status
     l = lines
     @status = l > 0 ? "line #{@curpos + 1} of #{l}" : ""
   end
 
   def call_load_more_callbacks size
     @load_more_q.push size if $config[:load_more_threads_when_scrolling]
   end
 end
 end