Class: Bijou::Context

Inherits:
Object
  • Object
show all
Defined in:
lib/bijou/context.rb

Overview

When a Bijou file is loaded by the processor, each component that is encountered causes a Bijou::Component class to be instantiated in the context. This context can then be executed with a set of input arguments, causing each component to be evaluated and the output to be rendered. A context may be used to invoke the same arrangement of components any number of times with different arguments.

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(config, environment = nil) ⇒ Context

Returns a new instance of Context.



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# File 'lib/bijou/context.rb', line 173

def initialize(config, environment=nil)
  if !environment 
    environment = Environment.new
    environment.trace_level = config.trace_level
    environment.trace_buffer = config.trace_buffer
  end
  
  @args = {}
  @stack = Stack.new
  @config = config
  @environment = environment
  @container_callback = nil
  @component_callback = nil

  @request = nil
  @response = nil

  @cgi = nil
end

Instance Attribute Details

#cgi ⇒ Object

Returns the value of attribute cgi.



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# File 'lib/bijou/context.rb', line 169

def cgi
  @cgi
end

#component_callback ⇒ Object

Returns the value of attribute component_callback.



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# File 'lib/bijou/context.rb', line 163

def component_callback
  @component_callback
end

#config ⇒ Object (readonly)

Returns the value of attribute config.



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# File 'lib/bijou/context.rb', line 166

def config
  @config
end

#container_callback ⇒ Object

Returns the value of attribute container_callback.



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# File 'lib/bijou/context.rb', line 164

def container_callback
  @container_callback
end

#environment ⇒ Object (readonly)

Returns the value of attribute environment.



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# File 'lib/bijou/context.rb', line 167

def environment
  @environment
end

#request ⇒ Object

Returns the value of attribute request.



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# File 'lib/bijou/context.rb', line 170

def request
  @request
end

#response ⇒ Object

Returns the value of attribute response.



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# File 'lib/bijou/context.rb', line 171

def response
  @response
end

#stack ⇒ Object (readonly)

Returns the value of attribute stack.



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# File 'lib/bijou/context.rb', line 165

def stack
  @stack
end

Instance Method Details

#add_component(component) ⇒ Object 



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# File 'lib/bijou/context.rb', line 233

def add_component(component)
  @stack.push_frame(component)

  # If the owner registered a container load handler, invoke after the
  # component has been added.
  if component.class.container && @container_callback
    @container_callback.call(self, component.class.container)
  end
end

#argument_exception(method, name) ⇒ Object 



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# File 'lib/bijou/context.rb', line 398

def argument_exception(method, name)
  # BUGBUG: We need to print the page (component) name.
  raise "Expected argument '#{name}' to method '#{method}'"
end

#cache_filename ⇒ Object

Used to retrieve the last active frame in the event of an exception.



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# File 'lib/bijou/context.rb', line 225

def cache_filename
  if @environment.component
    @environment.component.class.cache_filename
  else
    nil
  end
end

#call_next(extra = {}) ⇒ Object

Container modules render their callers by calling the content method once at the location where the caller’s output should be rendered.



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# File 'lib/bijou/context.rb', line 297

def call_next(extra={})
  if @stack.index == 0
    raise 'next called too many times'
  end

  # Flush the first part of the component's output to the stack's buffer.
  @stack.flush_frame

  prev_component = @environment.component

  # REVIEW: Argument merge and override is experimental.
  # Render the child content.
  component = @stack.next_frame.component
  @environment.component = component
  component.render(@args.merge(extra))
  @environment.component = prev_component

  # The remainder of the content will be flushed at the end of render.
  # @stack.flush_frame
end

#clear ⇒ Object 



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# File 'lib/bijou/context.rb', line 211

def clear
  @stack.flush
end

#fetch_next ⇒ Object 



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# File 'lib/bijou/context.rb', line 326

def fetch_next
  try_fetch_next || raise('fetch_next cannot find next component')
end

#fetch_remainder ⇒ Object 



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# File 'lib/bijou/context.rb', line 338

def fetch_remainder
  try_fetch_remainder || raise('fetch_remainder cannot find next component')
end

#get_log ⇒ Object 



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# File 'lib/bijou/context.rb', line 413

def get_log()
  @environment.get_log()
end

#get_trace ⇒ Object 



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# File 'lib/bijou/context.rb', line 427

def get_trace()
  @environment.get_trace()
end

#invoke(name, args) ⇒ Object

Used to invoke a method or a component. The output is rendered to the buffer. Returns true if a match was found.



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# File 'lib/bijou/context.rb', line 383

def invoke(name, args)
  if name == 'content'
    # REVIEW: This is an experimental feature. An alternative (without 
    # argument support) is <%content>, but it is an unclosed tag.
    return call_next(args)
  end

  if text = sinvoke(name, args)
    write text
    return true
  end

  false
end

#log(level, str) ⇒ Object

Logs with carriage return.



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# File 'lib/bijou/context.rb', line 404

def log(level, str)
  @environment.log(level, str)
end

#log_(level, str) ⇒ Object

Logs without carriage return.



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# File 'lib/bijou/context.rb', line 409

def log_(level, str)
  @environment.log_(level, str)
end

#output ⇒ Object 



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# File 'lib/bijou/context.rb', line 207

def output
  @stack.buffer
end

#render(args) ⇒ Object 



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# File 'lib/bijou/context.rb', line 243

def render(args)
  trace Bijou::Log::Info, "render init"

  prev_component = @environment.component

  # Init may render, after the headers but before the page text.
  @stack.frames.each { |frame|
    @environment.component = frame.component
    frame.component.init(args)
  }

  @environment.component = prev_component

  # Render the component chain to the response target.
  render_component(args)

  trace Bijou::Log::Info, "render fini"

  # Fini may still render to the stream, at the end after the page text.
  @stack.frames.each { |frame|
    @environment.component = frame.component
    frame.component.fini()
  }

  @environment.component = prev_component

  return @output
end

#render_component(args) ⇒ Object

The render method renders the component chain.



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# File 'lib/bijou/context.rb', line 273

def render_component(args)
  if @stack.frames.length == 0
    return
  end

  # Set top-level args so they are available to all components.
  @args = args

  # Start with the outer-most container at the end of the list.
  @stack.start

  prev_component = @environment.component

  component = @stack.top_frame.component
  @environment.component = component
  component.render(@args)
  @environment.component = prev_component

  # This flushes the component's output to the stack's buffer.
  @stack.flush_frame
end

#reset ⇒ Object

Called after clone



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# File 'lib/bijou/context.rb', line 194

def reset()
  @args = {}
  @stack = Stack.new
end

#sinvoke(name, args) ⇒ Object

Used to invoke a method or a component. The output is rendered to a string, which is returned as the result. If no match is found returns nil.



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# File 'lib/bijou/context.rb', line 344

def sinvoke(name, args)
  # Does this look like a method? We don't include setters, etc. (?!=).
  if name =~ /[_a-z][_a-z0-9]*/
    prev_component = @environment.component

    # Do any of the components support this method?
    @stack.frames.each { |f|
      if f.component.respond_to?(name)
        @stack.flush_frame
        @environment.component = f.component
        m = f.component.method(name)
        m.call(args)
        @environment.component = prev_component
        return @stack.top_frame.flush
      end
    }

    @environment.component = prev_component
  end
  
  # Delegate to context owner
  if @component_callback
    # The subcontext wraps a new stack for the component, but shares 
    # common data. This allows us to encapsulate the rendered output
    # into a separate buffer chain.
    subcontext = self.clone
    subcontext.reset

    # TODO: Handle new context and buffer merging.
    @component_callback.call(subcontext, name, args)

    return subcontext.stack.flush
  end

  nil
end

#source_filename ⇒ Object

Used to retrieve the last active frame in the event of an exception.



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# File 'lib/bijou/context.rb', line 216

def source_filename
  if @environment.component
    @environment.component.class.source_filename
  else
    nil
  end
end

#trace(level, str) ⇒ Object

Trace with carriage return.



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# File 'lib/bijou/context.rb', line 418

def trace(level, str)
  @environment.trace(level, str)
end

#trace_(level, str) ⇒ Object

Trace without carriage return.



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# File 'lib/bijou/context.rb', line 423

def trace_(level, str)
  @environment.trace_(level, str)
end

#try_fetch_next ⇒ Object 



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# File 'lib/bijou/context.rb', line 318

def try_fetch_next
  if @stack.index == 0
    nil
  else
    @stack.peek_frame
  end
end

#try_fetch_remainder ⇒ Object 



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# File 'lib/bijou/context.rb', line 330

def try_fetch_remainder
  if @stack.index == 0
    nil
  else
    @stack.frames[0, @stack.index].reverse
  end
end

#write(str) ⇒ Object 



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# File 'lib/bijou/context.rb', line 199

def write(str)
  @stack.output << str
end

#writeline(str) ⇒ Object 



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# File 'lib/bijou/context.rb', line 203

def writeline(str)
  @stack.output << str + "\n"
end