524 lines
14 KiB
Ruby
524 lines
14 KiB
Ruby
require 'rexml/namespace'
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require 'rexml/xmltokens'
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require 'rexml/parsers/xpathparser'
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module REXML
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# You don't want to use this class. Really. Use XPath, which is a wrapper
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# for this class. Believe me. You don't want to poke around in here.
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# There is strange, dark magic at work in this code. Beware. Go back! Go
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# back while you still can!
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class XPathParser
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include XMLTokens
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LITERAL = /^'([^']*)'|^"([^"]*)"/u
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def initialize( )
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@parser = REXML::Parsers::XPathParser.new
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@namespaces = {}
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@variables = {}
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end
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def namespaces=( namespaces={} )
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Functions::namespace_context = namespaces
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@namespaces = namespaces
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end
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def variables=( vars={} )
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Functions::variables = vars
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@variables = vars
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end
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def parse path, nodeset
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path_stack = @parser.parse( path )
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#puts "PARSE: #{path} => #{path_stack.inspect}"
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match( path_stack, nodeset )
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end
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def predicate path, nodeset
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path_stack = @parser.predicate( path )
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return Predicate( path_stack, nodeset )
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end
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def []=( variable_name, value )
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@variables[ variable_name ] = value
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end
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private
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def match( path_stack, nodeset )
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while ( path_stack.size > 0 and nodeset.size > 0 )
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#puts "PARSE: #{path_stack.inspect} '#{nodeset.collect{|n|n.type}.inspect}'"
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nodeset = internal_parse( path_stack, nodeset )
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#puts "NODESET: #{nodeset.size}"
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#puts "PATH_STACK: #{path_stack.inspect}"
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end
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nodeset
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end
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def internal_parse path_stack, nodeset
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return nodeset if nodeset.size == 0 or path_stack.size == 0
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#puts "INTERNAL_PARSE: #{path_stack.inspect}, #{nodeset.collect{|n| n.type}.inspect}"
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case path_stack.shift
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when :document
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return [ nodeset[0].root.parent ]
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when :qname
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prefix = path_stack.shift
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name = path_stack.shift
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#puts "QNAME #{prefix}#{prefix.size>0?':':''}#{name}"
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n = nodeset.clone
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ns = @namespaces[prefix]
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ns = ns ? ns : ''
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n.delete_if do |node|
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# FIXME: This DOUBLES the time XPath searches take
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ns = node.namespace( prefix ) if node.node_type == :element and ns == ''
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#puts "NODE: '#{node.to_s}'; node.has_name?( #{name.inspect}, #{ns.inspect} ): #{ node.has_name?( name, ns )}; node.namespace() = #{node.namespace().inspect}; node.prefix = #{node.prefix().inspect}" if node.node_type == :element
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!(node.node_type == :element and node.name == name and node.namespace == ns )
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end
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return n
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when :any
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n = nodeset.clone
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n.delete_if { |node| node.node_type != :element }
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return n
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when :self
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# THIS SPACE LEFT INTENTIONALLY BLANK
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when :processing_instruction
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target = path_stack.shift
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n = nodeset.clone
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n.delete_if do |node|
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(node.node_type != :processing_instruction) or
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( !target.nil? and ( node.target != target ) )
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end
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return n
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when :text
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#puts ":TEXT"
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n = nodeset.clone
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n.delete_if do |node|
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#puts "#{node} :: #{node.node_type}"
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node.node_type != :text
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end
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return n
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when :comment
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n = nodeset.clone
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n.delete_if do |node|
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node.node_type != :comment
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end
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return n
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when :node
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return nodeset
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#n = nodeset.clone
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#n.delete_if do |node|
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# !node.node?
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#end
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#return n
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# FIXME: I suspect the following XPath will fail:
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# /a/*/*[1]
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when :child
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#puts "CHILD"
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new_nodeset = []
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nt = nil
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for node in nodeset
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nt = node.node_type
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new_nodeset += node.children if nt == :element or nt == :document
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end
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#path_stack[0,(path_stack.size-ps_clone.size)] = []
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return new_nodeset
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when :literal
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literal = path_stack.shift
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if literal =~ /^\d+(\.\d+)?$/
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return ($1 ? literal.to_f : literal.to_i)
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end
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#puts "RETURNING '#{literal}'"
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return literal
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when :attribute
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#puts ":ATTRIBUTE"
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new_nodeset = []
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case path_stack.shift
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when :qname
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prefix = path_stack.shift
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name = path_stack.shift
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for element in nodeset
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if element.node_type == :element
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#puts element.name
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#puts "looking for attribute #{name} in '#{@namespaces[prefix]}'"
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attr = element.attribute( name, @namespaces[prefix] )
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#puts ":ATTRIBUTE: attr => #{attr}"
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new_nodeset << attr if attr
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end
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end
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when :any
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for element in nodeset
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if element.node_type == :element
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attr = element.attributes
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end
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end
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end
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#puts "RETURNING #{new_nodeset.collect{|n|n.to_s}.inspect}"
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return new_nodeset
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when :parent
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return internal_parse( path_stack, nodeset.collect{|n| n.parent}.compact )
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when :ancestor
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#puts "ANCESTOR"
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new_nodeset = []
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for node in nodeset
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while node.parent
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node = node.parent
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new_nodeset << node unless new_nodeset.include? node
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end
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end
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#nodeset = new_nodeset.uniq
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return new_nodeset
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when :ancestor_or_self
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new_nodeset = []
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for node in nodeset
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if node.node_type == :element
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new_nodeset << node
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while ( node.parent )
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node = node.parent
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new_nodeset << node unless new_nodeset.includes? node
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end
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end
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end
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#nodeset = new_nodeset.uniq
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return new_nodeset
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when :predicate
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#puts "@"*80
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#puts "NODESET = #{nodeset.collect{|n|n.to_s}.inspect}"
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predicate = path_stack.shift
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new_nodeset = []
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Functions::size = nodeset.size
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nodeset.size.times do |index|
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node = nodeset[index]
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Functions::node = node
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Functions::index = index+1
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#puts "Node #{node} and index=#{index+1}"
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result = Predicate( predicate, node )
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#puts "Predicate returned #{result} (#{result.type}) for #{node.type}"
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if result.kind_of? Numeric
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#puts "#{result} == #{index} => #{result == index}"
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new_nodeset << node if result == (index+1)
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elsif result.instance_of? Array
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new_nodeset << node if result.size > 0
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else
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new_nodeset << node if result
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end
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end
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#puts "Nodeset after predicate #{predicate.inspect} has #{new_nodeset.size} nodes"
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#puts "NODESET: #{new_nodeset.collect{|n|n.to_s}.inspect}"
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return new_nodeset
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when :descendant_or_self
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rv = descendant_or_self( path_stack, nodeset )
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path_stack.clear
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return rv
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when :descendant
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#puts ":DESCENDANT"
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results = []
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nt = nil
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for node in nodeset
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nt = node.node_type
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results += internal_parse( path_stack.clone.unshift( :descendant_or_self ),
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node.children ) if nt == :element or nt == :document
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end
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return results
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when :following_sibling
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results = []
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for node in nodeset
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all_siblings = node.parent.children
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current_index = all_siblings.index( node )
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following_siblings = all_siblings[ current_index+1 .. -1 ]
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results += internal_parse( path_stack.clone, following_siblings )
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end
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return results
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when :preceding_sibling
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results = []
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for node in nodeset
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all_siblings = node.parent.children
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current_index = all_siblings.index( node )
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preceding_siblings = all_siblings[ 0 .. current_index-1 ]
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results += internal_parse( path_stack.clone, preceding_siblings )
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end
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return results
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when :preceding
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new_nodeset = []
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for node in nodeset
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new_nodeset += preceding( node )
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end
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return new_nodeset
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when :following
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new_nodeset = []
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for node in nodeset
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new_nodeset += following( node )
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end
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return new_nodeset
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when :namespace
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new_set = []
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for node in nodeset
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new_nodeset << node.namespace if node.node_type == :element or node.node_type == :attribute
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end
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return new_nodeset
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when :variable
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var_name = path_stack.shift
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return @variables[ var_name ]
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end
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nodeset
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end
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##########################################################
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# The next two methods are BAD MOJO!
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# This is my achilles heel. If anybody thinks of a better
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# way of doing this, be my guest. This really sucks, but
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# it took me three days to get it to work at all.
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# ########################################################
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def descendant_or_self( path_stack, nodeset )
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rs = []
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d_o_s( path_stack, nodeset, rs )
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#puts "RS = #{rs.collect{|n|n.to_s}.inspect}"
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rs.flatten.compact
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end
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def d_o_s( p, ns, r )
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#puts r.collect{|n|n.to_s}.inspect
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#puts ns.collect{|n|n.to_s}.inspect
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nt = nil
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ns.each_index do |i|
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n = ns[i]
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x = match( p.clone, [ n ] )
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#puts "Got a match on #{p.inspect} for #{ns.collect{|n|n.to_s+"("+n.type.to_s+")"}.inspect}"
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nt = n.node_type
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d_o_s( p, n.children, x ) if nt == :element or nt == :document
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r[i,0] = [x] if x.size > 0
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end
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end
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def recurse( nodeset, &block )
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for node in nodeset
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yield node
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recurse( node, &block ) if node.node_type == :element
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end
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end
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# Given a predicate, a node, and a context, evaluates to true or false.
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def Predicate( predicate, node )
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predicate = predicate.clone
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#puts "#"*20
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#puts "Predicate( #{predicate.inspect}, #{node.type} )"
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results = []
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case (predicate[0])
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when :and, :or, :eq, :neq, :lt, :lteq, :gt, :gteq
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eq = predicate.shift
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left = Predicate( predicate.shift, node )
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right = Predicate( predicate.shift, node )
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return equality_relational_compare( left, eq, right )
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when :div, :mod, :mult, :plus, :minus, :union
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op = predicate.shift
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left = Predicate( predicate.shift, node )
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right = Predicate( predicate.shift, node )
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left = Functions::number( left )
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right = Functions::number( right )
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case op
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when :div
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return left.to_f / right.to_f
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when :mod
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return left % right
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when :mult
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return left * right
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when :plus
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return left + right
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when :minus
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return left - right
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when :union
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return (left | right)
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end
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when :neg
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predicate.shift
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operand = Functions::number(Predicate( predicate, node ))
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return -operand
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when :not
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predicate.shift
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return !Predicate( predicate.shift, node )
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when :function
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predicate.shift
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func_name = predicate.shift.tr('-', '_')
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arguments = predicate.shift
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#puts "\nFUNCTION: #{func_name}"
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#puts "ARGUMENTS: #{arguments.inspect} #{node.to_s}"
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args = arguments.collect { |arg| Predicate( arg, node ) }
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#puts "FUNCTION: #{func_name}( #{args.collect{|n|n.to_s}.inspect} )"
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result = Functions.send( func_name, *args )
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#puts "RESULTS: #{result.inspect}"
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return result
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else
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return match( predicate, [ node ] )
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end
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end
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# Builds a nodeset of all of the following nodes of the supplied node,
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# in document order
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def following( node )
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all_siblings = node.parent.children
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current_index = all_siblings.index( node )
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following_siblings = all_siblings[ current_index+1 .. -1 ]
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following = []
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recurse( following_siblings ) { |node| following << node }
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following.shift
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#puts "following is returning #{puta following}"
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following
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end
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# Builds a nodeset of all of the preceding nodes of the supplied node,
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# in reverse document order
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def preceding( node )
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all_siblings = node.parent.children
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current_index = all_siblings.index( node )
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preceding_siblings = all_siblings[ 0 .. current_index-1 ]
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preceding_siblings.reverse!
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preceding = []
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recurse( preceding_siblings ) { |node| preceding << node }
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preceding.reverse
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end
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def equality_relational_compare( set1, op, set2 )
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#puts "EQ_REL_COMP: #{set1.to_s}, #{op}, #{set2.to_s}"
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if set1.kind_of? Array and set2.kind_of? Array
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if set1.size == 1 and set2.size == 1
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set1 = set1[0]
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set2 = set2[0]
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else
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set1.each do |i1|
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i1 = i1.to_s
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set2.each do |i2|
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i2 = i2.to_s
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return true if compare( i1, op, i2 )
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end
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end
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return false
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end
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end
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#puts "COMPARING VALUES"
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# If one is nodeset and other is number, compare number to each item
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# in nodeset s.t. number op number(string(item))
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# If one is nodeset and other is string, compare string to each item
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# in nodeset s.t. string op string(item)
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# If one is nodeset and other is boolean, compare boolean to each item
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# in nodeset s.t. boolean op boolean(item)
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if set1.kind_of? Array or set2.kind_of? Array
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#puts "ISA ARRAY"
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if set1.kind_of? Array
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a = set1
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b = set2.to_s
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else
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a = set2
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b = set1.to_s
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end
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case b
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when 'true', 'false'
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b = Functions::boolean( b )
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for v in a
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v = Functions::boolean(v)
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return true if compare( v, op, b )
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end
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when /^\d+(\.\d+)?$/
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b = Functions::number( b )
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for v in a
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v = Functions::number(v)
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return true if compare( v, op, b )
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end
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else
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b = Functions::string( b )
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for v in a
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v = Functions::string(v)
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return true if compare( v, op, b )
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end
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end
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else
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# If neither is nodeset,
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# If op is = or !=
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# If either boolean, convert to boolean
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# If either number, convert to number
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# Else, convert to string
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# Else
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# Convert both to numbers and compare
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s1 = set1.to_s
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s2 = set2.to_s
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#puts "EQ_REL_COMP: #{set1}=>#{s1}, #{set2}=>#{s2}"
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if s1 == 'true' or s1 == 'false' or s2 == 'true' or s2 == 'false'
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#puts "Functions::boolean(#{set1})=>#{Functions::boolean(set1)}"
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#puts "Functions::boolean(#{set2})=>#{Functions::boolean(set2)}"
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set1 = Functions::boolean( set1 )
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set2 = Functions::boolean( set2 )
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else
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if op == :eq or op == :neq
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if s1 =~ /^\d+(\.\d+)?$/ or s2 =~ /^\d+(\.\d+)?$/
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set1 = Functions::number( s1 )
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set2 = Functions::number( s2 )
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else
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set1 = Functions::string( set1 )
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set2 = Functions::string( set2 )
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end
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else
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set1 = Functions::number( set1 )
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set2 = Functions::number( set2 )
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end
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end
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#puts "EQ_REL_COMP: #{set1} #{op} #{set2}"
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return compare( set1, op, set2 )
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end
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return false
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end
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def compare a, op, b
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case op
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when :eq
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a == b
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when :neq
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a != b
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when :lt
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a < b
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when :lteq
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a <= b
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when :gt
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a > b
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when :gteq
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a >= b
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when :and
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a and b
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when :or
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a or b
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else
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false
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end
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end
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end
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end
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