Class: Canon::Comparison::XmlComparatorHelpers::NamespaceComparator

Inherits:
Object
  • Object
show all
Defined in:
lib/canon/comparison/xml_comparator/namespace_comparator.rb

Overview

Namespace declaration comparison logic Handles comparison of xmlns and xmlns:* attributes

Class Method Summary collapse

Class Method Details

.add_namespace_difference(node1, node2, missing, extra, changed, opts, differences) ⇒ Object

Add a namespace declaration difference

Parameters:

  • node1 (Object) —

    First node

  • node2 (Object) —

    Second node

  • missing (Array) —

    Missing prefixes

  • extra (Array) —

    Extra prefixes

  • changed (Array) —

    Changed prefixes

  • opts (Hash) —

    Options

  • differences (Array) —

    Array to append difference to



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# File 'lib/canon/comparison/xml_comparator/namespace_comparator.rb', line 137

def self.add_namespace_difference(node1, node2, missing, extra,
changed, opts, differences)
  # Build a descriptive reason
  reasons = []
  if missing.any?
    reasons << "removed: #{missing.map do |p|
      p.empty? ? 'xmlns' : "xmlns:#{p}"
    end.join(', ')}"
  end
  if extra.any?
    reasons << "added: #{extra.map do |p|
      p.empty? ? 'xmlns' : "xmlns:#{p}"
    end.join(', ')}"
  end
  if changed.any?
    reasons << "changed: #{changed.map do |p|
      p.empty? ? 'xmlns' : "xmlns:#{p}"
    end.join(', ')}"
  end

  diff_node = Canon::Comparison::DiffNodeBuilder.build(
    node1: node1,
    node2: node2,
    diff1: Comparison::UNEQUAL_ATTRIBUTES,
    diff2: Comparison::UNEQUAL_ATTRIBUTES,
    dimension: :namespace_declarations,
    **opts,
  )
  differences << diff_node if diff_node
end

.compare(node1, node2, opts, differences) ⇒ Symbol

Compare namespace declarations between two nodes

Parameters:

  • node1 (Object) —

    First node

  • node2 (Object) —

    Second node

  • opts (Hash) —

    Comparison options

  • differences (Array) —

    Array to append differences to

Returns:

  • (Symbol) —

    Comparison result



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# File 'lib/canon/comparison/xml_comparator/namespace_comparator.rb', line 16

def self.compare(node1, node2, opts, differences)
  ns_decls1 = extract_declarations(node1)
  ns_decls2 = extract_declarations(node2)

  # Most element pairs declare nothing — skip the set algebra.
  return Comparison::EQUIVALENT if ns_decls1.empty? && ns_decls2.empty?

  # Find missing, extra, and changed namespace declarations
  missing = ns_decls1.keys - ns_decls2.keys  # In node1 but not node2
  extra = ns_decls2.keys - ns_decls1.keys    # In node2 but not node1
  changed = ns_decls1.select do |prefix, uri|
    ns_decls2[prefix] && ns_decls2[prefix] != uri
  end.keys

  # If there are any differences, create a DiffNode
  if missing.any? || extra.any? || changed.any?
    add_namespace_difference(node1, node2, missing, extra, changed,
                             opts, differences)
    return Comparison::UNEQUAL_ATTRIBUTES
  end

  Comparison::EQUIVALENT
end

.extract_declarations(node) ⇒ Hash

Extract namespace declarations from a node

Parameters:

  • node (Object) —

    Node to extract namespace declarations from

Returns:

  • (Hash) —

    Hash of prefix => URI mappings



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# File 'lib/canon/comparison/xml_comparator/namespace_comparator.rb', line 44

def self.extract_declarations(node)
  declarations = {}

  if node.is_a?(Canon::Xml::Node)
    if node.namespace_nodes
      return extract_from_namespace_nodes(node.namespace_nodes,
                                          declarations)
    end

    raw_attrs = node.attribute_nodes
  else
    raw_attrs = node.attributes
  end

  if raw_attrs.is_a?(Array)
    extract_from_array_attributes(raw_attrs, declarations)
  else
    extract_from_hash_attributes(raw_attrs, declarations)
  end

  declarations
end

.extract_from_array_attributes(raw_attrs, declarations) ⇒ Hash

Extract from array-format attributes

Parameters:

  • raw_attrs (Array) —

    Array of AttributeNode objects

  • declarations (Hash) —

    Output hash to populate

Returns:

  • (Hash) —

    Declarations hash



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# File 'lib/canon/comparison/xml_comparator/namespace_comparator.rb', line 89

def self.extract_from_array_attributes(raw_attrs, declarations)
  raw_attrs.each do |attr|
    name = attr.name
    value = attr.value

    if namespace_declaration?(name)
      # Extract prefix: "xmlns" -> "", "xmlns:xmi" -> "xmi"
      prefix = name == "xmlns" ? "" : name.split(":", 2)[1]
      declarations[prefix] = value
    end
  end

  declarations
end

.extract_from_hash_attributes(raw_attrs, declarations) ⇒ Hash

Extract from hash-format attributes

Parameters:

  • raw_attrs (Hash) —

    Hash-like attributes

  • declarations (Hash) —

    Output hash to populate

Returns:

  • (Hash) —

    Declarations hash



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# File 'lib/canon/comparison/xml_comparator/namespace_comparator.rb', line 109

def self.extract_from_hash_attributes(raw_attrs, declarations)
  raw_attrs.each do |key, val|
    name = key.is_a?(String) ? key : key.name

    if namespace_declaration?(name)
      value = val.is_a?(String) ? val : val.value

      prefix = name == "xmlns" ? "" : name.split(":", 2)[1]
      declarations[prefix] = value
    end
  end

  declarations
end

.extract_from_namespace_nodes(namespace_nodes, declarations) ⇒ Hash

Extract from Canon::Xml::Node namespace_nodes

Parameters:

  • namespace_nodes (Array) —

    Array of NamespaceNode objects

  • declarations (Hash) —

    Output hash to populate

Returns:

  • (Hash) —

    Declarations hash



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# File 'lib/canon/comparison/xml_comparator/namespace_comparator.rb', line 72

def self.extract_from_namespace_nodes(namespace_nodes, declarations)
  namespace_nodes.each do |ns|
    # Skip the implicit xml namespace (always present)
    next if ns.prefix == "xml" && ns.uri == "http://www.w3.org/XML/1998/namespace"

    prefix = ns.prefix || ""
    declarations[prefix] = ns.uri
  end

  declarations
end

.namespace_declaration?(attr_name) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/canon/comparison/xml_comparator/namespace_comparator.rb', line 124

def self.namespace_declaration?(attr_name)
  Canon::Xml::NamespaceHelper.namespace_declaration?(attr_name)
end