Class: Rhales::ViewComposition

Inherits:
Object
  • Object
show all
Defined in:
lib/rhales/view_composition.rb

Overview

ViewComposition builds and represents the complete template dependency graph for a view render. It provides a data-agnostic, immutable representation of all templates (layout, view, partials) required for rendering.

This class is a key component in the two-pass rendering architecture, enabling server-side data aggregation before HTML generation.

Responsibilities: - Dependency Resolution: Recursively discovers and loads all partials - Structural Representation: Organizes templates into a traversable tree - Traversal Interface: Provides methods to iterate templates in render order

Key Characteristics: - Data-Agnostic: Knows nothing about runtime context or request data - Immutable: Once created, the composition is read-only - Cacheable: Can be cached in production for performance

Defined Under Namespace

Classes: CircularDependencyError, TemplateNotFoundError

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(root_template_name, loader:, config: nil) ⇒ ViewComposition

Returns a new instance of ViewComposition.



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# File 'lib/rhales/view_composition.rb', line 31

def initialize(root_template_name, loader:, config: nil)
  @root_template_name = root_template_name
  @loader             = loader
  @config             = config
  @templates          = {}
  @dependencies       = {}
  @loading            = Set.new
end

Instance Attribute Details

#dependencies ⇒ Object (readonly)

Returns the value of attribute dependencies.



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# File 'lib/rhales/view_composition.rb', line 29

def dependencies
  @dependencies
end

#root_template_name ⇒ Object (readonly)

Returns the value of attribute root_template_name.



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# File 'lib/rhales/view_composition.rb', line 29

def root_template_name
  @root_template_name
end

#templates ⇒ Object (readonly)

Returns the value of attribute templates.



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# File 'lib/rhales/view_composition.rb', line 29

def templates
  @templates
end

Instance Method Details

#dependencies_of(template_name) ⇒ Object

Get direct dependencies of a template



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# File 'lib/rhales/view_composition.rb', line 83

def dependencies_of(template_name)
  @dependencies[template_name] || []
end

#each_document_in_render_order ⇒ Object

Iterate through all documents in render order Layout -> View -> Partials (depth-first)



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# File 'lib/rhales/view_composition.rb', line 49

def each_document_in_render_order(&)
  return enum_for(:each_document_in_render_order) unless block_given?

  visited = Set.new

  # Process layout first if specified
  root_doc = @templates[@root_template_name]
  if root_doc && root_doc.layout
    layout_name = root_doc.layout
    if @templates[layout_name]
      yield_template_recursive(layout_name, visited, &)
    end
  end

  # Then process the root template and its dependencies
  yield_template_recursive(@root_template_name, visited, &)
end

#extract_partials(parser) ⇒ Object (private) 



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# File 'lib/rhales/view_composition.rb', line 128

def extract_partials(parser)
  partials         = Set.new
  template_content = parser.section('template')

  return partials unless template_content

  # Extract partial references from template
  # Looking for {{> partial_name}} patterns
  template_content.scan(/\{\{>\s*([^\s}]+)\s*\}\}/) do |match|
    partials.add(match[0])
  end

  partials
end

#freeze_composition ⇒ Object (private) 



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# File 'lib/rhales/view_composition.rb', line 159

def freeze_composition
  @templates.freeze
  @dependencies.freeze
  @templates.each_value(&:freeze)
  @dependencies.each_value(&:freeze)
  freeze
end

#load_template_recursive(template_name, _parent_path = nil) ⇒ Object (private) 



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# File 'lib/rhales/view_composition.rb', line 90

def load_template_recursive(template_name, _parent_path = nil)
  # Check for circular dependencies
  if @loading.include?(template_name)
    raise CircularDependencyError, "Circular dependency detected: #{template_name} -> #{@loading.to_a.join(' -> ')}"
  end

  # Skip if already loaded
  return if @templates.key?(template_name)

  @loading.add(template_name)

  begin
    # Load template using the provided loader
    parser = @loader.call(template_name)

    unless parser
      raise TemplateNotFoundError, "Template not found: #{template_name}"
    end

    # Store the template
    @templates[template_name]    = parser
    @dependencies[template_name] = []

    # Extract and load partials
    extract_partials(parser).each do |partial_name|
      @dependencies[template_name] << partial_name
      load_template_recursive(partial_name, template_name)
    end

    # Load layout if specified and not already loaded
    if parser.layout && !@templates.key?(parser.layout)
      load_template_recursive(parser.layout, template_name)
    end
  ensure
    @loading.delete(template_name)
  end
end

#resolve! ⇒ Object

Resolve all template dependencies



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# File 'lib/rhales/view_composition.rb', line 41

def resolve!
  load_template_recursive(@root_template_name)
  freeze_composition
  self
end

#template(name) ⇒ Object

Get a specific template by name



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# File 'lib/rhales/view_composition.rb', line 68

def template(name)
  @templates[name]
end

#template?(name) ⇒ Boolean

Check if a template exists in the composition

Returns:

  • (Boolean) 


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# File 'lib/rhales/view_composition.rb', line 73

def template?(name)
  @templates.key?(name)
end

#template_names ⇒ Object

Get all template names



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# File 'lib/rhales/view_composition.rb', line 78

def template_names
  @templates.keys
end

#yield_template_recursive(template_name, visited) ⇒ Object (private) 



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# File 'lib/rhales/view_composition.rb', line 143

def yield_template_recursive(template_name, visited, &)
  return if visited.include?(template_name)

  visited.add(template_name)

  # First yield dependencies (partials)
  (@dependencies[template_name] || []).each do |dep_name|
    yield_template_recursive(dep_name, visited, &)
  end

  # Then yield the template itself
  if @templates[template_name]
    yield template_name, @templates[template_name]
  end
end