JezK
Edit File: xpath_parser.rb
require 'rexml/namespace' require 'rexml/xmltokens' require 'rexml/attribute' require 'rexml/syncenumerator' require 'rexml/parsers/xpathparser' class Object def dclone clone end end class Symbol def dclone ; self ; end end class Fixnum def dclone ; self ; end end class Float def dclone ; self ; end end class Array def dclone klone = self.clone klone.clear self.each{|v| klone << v.dclone} klone end end module REXML # You don't want to use this class. Really. Use XPath, which is a wrapper # for this class. Believe me. You don't want to poke around in here. # There is strange, dark magic at work in this code. Beware. Go back! Go # back while you still can! class XPathParser include XMLTokens LITERAL = /^'([^']*)'|^"([^"]*)"/u def initialize( ) @parser = REXML::Parsers::XPathParser.new @namespaces = nil @variables = {} end def namespaces=( namespaces={} ) Functions::namespace_context = namespaces @namespaces = namespaces end def variables=( vars={} ) Functions::variables = vars @variables = vars end def parse path, nodeset #puts "#"*40 path_stack = @parser.parse( path ) #puts "PARSE: #{path} => #{path_stack.inspect}" #puts "PARSE: nodeset = #{nodeset.inspect}" match( path_stack, nodeset ) end def get_first path, nodeset #puts "#"*40 path_stack = @parser.parse( path ) #puts "PARSE: #{path} => #{path_stack.inspect}" #puts "PARSE: nodeset = #{nodeset.inspect}" first( path_stack, nodeset ) end def predicate path, nodeset path_stack = @parser.parse( path ) expr( path_stack, nodeset ) end def []=( variable_name, value ) @variables[ variable_name ] = value end # Performs a depth-first (document order) XPath search, and returns the # first match. This is the fastest, lightest way to return a single result. # # FIXME: This method is incomplete! def first( path_stack, node ) #puts "#{depth}) Entering match( #{path.inspect}, #{tree.inspect} )" return nil if path.size == 0 case path[0] when :document # do nothing return first( path[1..-1], node ) when :child for c in node.children #puts "#{depth}) CHILD checking #{name(c)}" r = first( path[1..-1], c ) #puts "#{depth}) RETURNING #{r.inspect}" if r return r if r end when :qname name = path[2] #puts "#{depth}) QNAME #{name(tree)} == #{name} (path => #{path.size})" if node.name == name #puts "#{depth}) RETURNING #{tree.inspect}" if path.size == 3 return node if path.size == 3 return first( path[3..-1], node ) else return nil end when :descendant_or_self r = first( path[1..-1], node ) return r if r for c in node.children r = first( path, c ) return r if r end when :node return first( path[1..-1], node ) when :any return first( path[1..-1], node ) end return nil end def match( path_stack, nodeset ) #puts "MATCH: path_stack = #{path_stack.inspect}" #puts "MATCH: nodeset = #{nodeset.inspect}" r = expr( path_stack, nodeset ) #puts "MAIN EXPR => #{r.inspect}" r end private # Returns a String namespace for a node, given a prefix # The rules are: # # 1. Use the supplied namespace mapping first. # 2. If no mapping was supplied, use the context node to look up the namespace def get_namespace( node, prefix ) if @namespaces return @namespaces[prefix] || '' else return node.namespace( prefix ) if node.node_type == :element return '' end end # Expr takes a stack of path elements and a set of nodes (either a Parent # or an Array and returns an Array of matching nodes ALL = [ :attribute, :element, :text, :processing_instruction, :comment ] ELEMENTS = [ :element ] def expr( path_stack, nodeset, context=nil ) #puts "#"*15 #puts "In expr with #{path_stack.inspect}" #puts "Returning" if path_stack.length == 0 || nodeset.length == 0 node_types = ELEMENTS return nodeset if path_stack.length == 0 || nodeset.length == 0 while path_stack.length > 0 #puts "#"*5 #puts "Path stack = #{path_stack.inspect}" #puts "Nodeset is #{nodeset.inspect}" if nodeset.length == 0 path_stack.clear return [] end case (op = path_stack.shift) when :document nodeset = [ nodeset[0].root_node ] #puts ":document, nodeset = #{nodeset.inspect}" when :qname #puts "IN QNAME" prefix = path_stack.shift name = path_stack.shift nodeset.delete_if do |node| # FIXME: This DOUBLES the time XPath searches take ns = get_namespace( node, prefix ) #puts "NS = #{ns.inspect}" #puts "node.node_type == :element => #{node.node_type == :element}" if node.node_type == :element #puts "node.name == #{name} => #{node.name == name}" if node.name == name #puts "node.namespace == #{ns.inspect} => #{node.namespace == ns}" end end !(node.node_type == :element and node.name == name and node.namespace == ns ) end node_types = ELEMENTS when :any #puts "ANY 1: nodeset = #{nodeset.inspect}" #puts "ANY 1: node_types = #{node_types.inspect}" nodeset.delete_if { |node| !node_types.include?(node.node_type) } #puts "ANY 2: nodeset = #{nodeset.inspect}" when :self # This space left intentionally blank when :processing_instruction target = path_stack.shift nodeset.delete_if do |node| (node.node_type != :processing_instruction) or ( target!='' and ( node.target != target ) ) end when :text nodeset.delete_if { |node| node.node_type != :text } when :comment nodeset.delete_if { |node| node.node_type != :comment } when :node # This space left intentionally blank node_types = ALL when :child new_nodeset = [] nt = nil for node in nodeset nt = node.node_type new_nodeset += node.children if nt == :element or nt == :document end nodeset = new_nodeset node_types = ELEMENTS when :literal return path_stack.shift when :attribute new_nodeset = [] case path_stack.shift when :qname prefix = path_stack.shift name = path_stack.shift for element in nodeset if element.node_type == :element #puts "Element name = #{element.name}" #puts "get_namespace( #{element.inspect}, #{prefix} ) = #{get_namespace(element, prefix)}" attrib = element.attribute( name, get_namespace(element, prefix) ) #puts "attrib = #{attrib.inspect}" new_nodeset << attrib if attrib end end when :any #puts "ANY" for element in nodeset if element.node_type == :element new_nodeset += element.attributes.to_a end end end nodeset = new_nodeset when :parent #puts "PARENT 1: nodeset = #{nodeset}" nodeset = nodeset.collect{|n| n.parent}.compact #nodeset = expr(path_stack.dclone, nodeset.collect{|n| n.parent}.compact) #puts "PARENT 2: nodeset = #{nodeset.inspect}" node_types = ELEMENTS when :ancestor new_nodeset = [] for node in nodeset while node.parent node = node.parent new_nodeset << node unless new_nodeset.include? node end end nodeset = new_nodeset node_types = ELEMENTS when :ancestor_or_self new_nodeset = [] for node in nodeset if node.node_type == :element new_nodeset << node while ( node.parent ) node = node.parent new_nodeset << node unless new_nodeset.include? node end end end nodeset = new_nodeset node_types = ELEMENTS when :predicate new_nodeset = [] subcontext = { :size => nodeset.size } pred = path_stack.shift nodeset.each_with_index { |node, index| subcontext[ :node ] = node #puts "PREDICATE SETTING CONTEXT INDEX TO #{index+1}" subcontext[ :index ] = index+1 pc = pred.dclone #puts "#{node.hash}) Recursing with #{pred.inspect} and [#{node.inspect}]" result = expr( pc, [node], subcontext ) result = result[0] if result.kind_of? Array and result.length == 1 #puts "#{node.hash}) Result = #{result.inspect} (#{result.class.name})" if result.kind_of? Numeric #puts "Adding node #{node.inspect}" if result == (index+1) new_nodeset << node if result == (index+1) elsif result.instance_of? Array if result.size > 0 and result.inject(false) {|k,s| s or k} #puts "Adding node #{node.inspect}" if result.size > 0 new_nodeset << node if result.size > 0 end else #puts "Adding node #{node.inspect}" if result new_nodeset << node if result end } #puts "New nodeset = #{new_nodeset.inspect}" #puts "Path_stack = #{path_stack.inspect}" nodeset = new_nodeset =begin predicate = path_stack.shift ns = nodeset.clone result = expr( predicate, ns ) #puts "Result = #{result.inspect} (#{result.class.name})" #puts "nodeset = #{nodeset.inspect}" if result.kind_of? Array nodeset = result.zip(ns).collect{|m,n| n if m}.compact else nodeset = result ? nodeset : [] end #puts "Outgoing NS = #{nodeset.inspect}" =end when :descendant_or_self rv = descendant_or_self( path_stack, nodeset ) path_stack.clear nodeset = rv node_types = ELEMENTS when :descendant results = [] nt = nil for node in nodeset nt = node.node_type results += expr( path_stack.dclone.unshift( :descendant_or_self ), node.children ) if nt == :element or nt == :document end nodeset = results node_types = ELEMENTS when :following_sibling #puts "FOLLOWING_SIBLING 1: nodeset = #{nodeset}" results = [] nodeset.each do |node| next if node.parent.nil? all_siblings = node.parent.children current_index = all_siblings.index( node ) following_siblings = all_siblings[ current_index+1 .. -1 ] results += expr( path_stack.dclone, following_siblings ) end #puts "FOLLOWING_SIBLING 2: nodeset = #{nodeset}" nodeset = results when :preceding_sibling results = [] nodeset.each do |node| next if node.parent.nil? all_siblings = node.parent.children current_index = all_siblings.index( node ) preceding_siblings = all_siblings[ 0, current_index ].reverse results += preceding_siblings end nodeset = results node_types = ELEMENTS when :preceding new_nodeset = [] for node in nodeset new_nodeset += preceding( node ) end #puts "NEW NODESET => #{new_nodeset.inspect}" nodeset = new_nodeset node_types = ELEMENTS when :following new_nodeset = [] for node in nodeset new_nodeset += following( node ) end nodeset = new_nodeset node_types = ELEMENTS when :namespace #puts "In :namespace" new_nodeset = [] prefix = path_stack.shift for node in nodeset if (node.node_type == :element or node.node_type == :attribute) if @namespaces namespaces = @namespaces elsif (node.node_type == :element) namespaces = node.namespaces else namespaces = node.element.namesapces end #puts "Namespaces = #{namespaces.inspect}" #puts "Prefix = #{prefix.inspect}" #puts "Node.namespace = #{node.namespace}" if (node.namespace == namespaces[prefix]) new_nodeset << node end end end nodeset = new_nodeset when :variable var_name = path_stack.shift return @variables[ var_name ] # :and, :or, :eq, :neq, :lt, :lteq, :gt, :gteq # TODO: Special case for :or and :and -- not evaluate the right # operand if the left alone determines result (i.e. is true for # :or and false for :and). when :eq, :neq, :lt, :lteq, :gt, :gteq, :and, :or left = expr( path_stack.shift, nodeset.dup, context ) #puts "LEFT => #{left.inspect} (#{left.class.name})" right = expr( path_stack.shift, nodeset.dup, context ) #puts "RIGHT => #{right.inspect} (#{right.class.name})" res = equality_relational_compare( left, op, right ) #puts "RES => #{res.inspect}" return res when :and left = expr( path_stack.shift, nodeset.dup, context ) #puts "LEFT => #{left.inspect} (#{left.class.name})" if left == false || left.nil? || !left.inject(false) {|a,b| a | b} return [] end right = expr( path_stack.shift, nodeset.dup, context ) #puts "RIGHT => #{right.inspect} (#{right.class.name})" res = equality_relational_compare( left, op, right ) #puts "RES => #{res.inspect}" return res when :div left = Functions::number(expr(path_stack.shift, nodeset, context)).to_f right = Functions::number(expr(path_stack.shift, nodeset, context)).to_f return (left / right) when :mod left = Functions::number(expr(path_stack.shift, nodeset, context )).to_f right = Functions::number(expr(path_stack.shift, nodeset, context )).to_f return (left % right) when :mult left = Functions::number(expr(path_stack.shift, nodeset, context )).to_f right = Functions::number(expr(path_stack.shift, nodeset, context )).to_f return (left * right) when :plus left = Functions::number(expr(path_stack.shift, nodeset, context )).to_f right = Functions::number(expr(path_stack.shift, nodeset, context )).to_f return (left + right) when :minus left = Functions::number(expr(path_stack.shift, nodeset, context )).to_f right = Functions::number(expr(path_stack.shift, nodeset, context )).to_f return (left - right) when :union left = expr( path_stack.shift, nodeset, context ) right = expr( path_stack.shift, nodeset, context ) return (left | right) when :neg res = expr( path_stack, nodeset, context ) return -(res.to_f) when :not when :function func_name = path_stack.shift.tr('-','_') arguments = path_stack.shift #puts "FUNCTION 0: #{func_name}(#{arguments.collect{|a|a.inspect}.join(', ')})" subcontext = context ? nil : { :size => nodeset.size } res = [] cont = context nodeset.each_with_index { |n, i| if subcontext subcontext[:node] = n subcontext[:index] = i cont = subcontext end arg_clone = arguments.dclone args = arg_clone.collect { |arg| #puts "FUNCTION 1: Calling expr( #{arg.inspect}, [#{n.inspect}] )" expr( arg, [n], cont ) } #puts "FUNCTION 2: #{func_name}(#{args.collect{|a|a.inspect}.join(', ')})" Functions.context = cont res << Functions.send( func_name, *args ) #puts "FUNCTION 3: #{res[-1].inspect}" } return res end end # while #puts "EXPR returning #{nodeset.inspect}" return nodeset end ########################################################## # FIXME # The next two methods are BAD MOJO! # This is my achilles heel. If anybody thinks of a better # way of doing this, be my guest. This really sucks, but # it is a wonder it works at all. # ######################################################## def descendant_or_self( path_stack, nodeset ) rs = [] #puts "#"*80 #puts "PATH_STACK = #{path_stack.inspect}" #puts "NODESET = #{nodeset.collect{|n|n.inspect}.inspect}" d_o_s( path_stack, nodeset, rs ) #puts "RS = #{rs.collect{|n|n.inspect}.inspect}" document_order(rs.flatten.compact) #rs.flatten.compact end def d_o_s( p, ns, r ) #puts "IN DOS with #{ns.inspect}; ALREADY HAVE #{r.inspect}" nt = nil ns.each_index do |i| n = ns[i] #puts "P => #{p.inspect}" x = expr( p.dclone, [ n ] ) nt = n.node_type d_o_s( p, n.children, x ) if nt == :element or nt == :document and n.children.size > 0 r.concat(x) if x.size > 0 end end # Reorders an array of nodes so that they are in document order # It tries to do this efficiently. # # FIXME: I need to get rid of this, but the issue is that most of the XPath # interpreter functions as a filter, which means that we lose context going # in and out of function calls. If I knew what the index of the nodes was, # I wouldn't have to do this. Maybe add a document IDX for each node? # Problems with mutable documents. Or, rewrite everything. def document_order( array_of_nodes ) new_arry = [] array_of_nodes.each { |node| node_idx = [] np = node.node_type == :attribute ? node.element : node while np.parent and np.parent.node_type == :element node_idx << np.parent.index( np ) np = np.parent end new_arry << [ node_idx.reverse, node ] } #puts "new_arry = #{new_arry.inspect}" new_arry.sort{ |s1, s2| s1[0] <=> s2[0] }.collect{ |s| s[1] } end def recurse( nodeset, &block ) for node in nodeset yield node recurse( node, &block ) if node.node_type == :element end end # Builds a nodeset of all of the preceding nodes of the supplied node, # in reverse document order # preceding:: includes every element in the document that precedes this node, # except for ancestors def preceding( node ) #puts "IN PRECEDING" ancestors = [] p = node.parent while p ancestors << p p = p.parent end acc = [] p = preceding_node_of( node ) #puts "P = #{p.inspect}" while p if ancestors.include? p ancestors.delete(p) else acc << p end p = preceding_node_of( p ) #puts "P = #{p.inspect}" end acc end def preceding_node_of( node ) #puts "NODE: #{node.inspect}" #puts "PREVIOUS NODE: #{node.previous_sibling_node.inspect}" #puts "PARENT NODE: #{node.parent}" psn = node.previous_sibling_node if psn.nil? if node.parent.nil? or node.parent.class == Document return nil end return node.parent #psn = preceding_node_of( node.parent ) end while psn and psn.kind_of? Element and psn.children.size > 0 psn = psn.children[-1] end psn end def following( node ) #puts "IN PRECEDING" acc = [] p = next_sibling_node( node ) #puts "P = #{p.inspect}" while p acc << p p = following_node_of( p ) #puts "P = #{p.inspect}" end acc end def following_node_of( node ) #puts "NODE: #{node.inspect}" #puts "PREVIOUS NODE: #{node.previous_sibling_node.inspect}" #puts "PARENT NODE: #{node.parent}" if node.kind_of? Element and node.children.size > 0 return node.children[0] end return next_sibling_node(node) end def next_sibling_node(node) psn = node.next_sibling_node while psn.nil? if node.parent.nil? or node.parent.class == Document return nil end node = node.parent psn = node.next_sibling_node #puts "psn = #{psn.inspect}" end return psn end def norm b case b when true, false return b when 'true', 'false' return Functions::boolean( b ) when /^\d+(\.\d+)?$/ return Functions::number( b ) else return Functions::string( b ) end end def equality_relational_compare( set1, op, set2 ) #puts "EQ_REL_COMP(#{set1.inspect} #{op.inspect} #{set2.inspect})" if set1.kind_of? Array and set2.kind_of? Array #puts "#{set1.size} & #{set2.size}" if set1.size == 1 and set2.size == 1 set1 = set1[0] set2 = set2[0] elsif set1.size == 0 or set2.size == 0 nd = set1.size==0 ? set2 : set1 rv = nd.collect { |il| compare( il, op, nil ) } #puts "RV = #{rv.inspect}" return rv else res = [] enum = SyncEnumerator.new( set1, set2 ).each { |i1, i2| #puts "i1 = #{i1.inspect} (#{i1.class.name})" #puts "i2 = #{i2.inspect} (#{i2.class.name})" i1 = norm( i1 ) i2 = norm( i2 ) res << compare( i1, op, i2 ) } return res end end #puts "EQ_REL_COMP: #{set1.inspect} (#{set1.class.name}), #{op}, #{set2.inspect} (#{set2.class.name})" #puts "COMPARING VALUES" # If one is nodeset and other is number, compare number to each item # in nodeset s.t. number op number(string(item)) # If one is nodeset and other is string, compare string to each item # in nodeset s.t. string op string(item) # If one is nodeset and other is boolean, compare boolean to each item # in nodeset s.t. boolean op boolean(item) if set1.kind_of? Array or set2.kind_of? Array #puts "ISA ARRAY" if set1.kind_of? Array a = set1 b = set2 else a = set2 b = set1 end case b when true, false return a.collect {|v| compare( Functions::boolean(v), op, b ) } when Numeric return a.collect {|v| compare( Functions::number(v), op, b )} when /^\d+(\.\d+)?$/ b = Functions::number( b ) #puts "B = #{b.inspect}" return a.collect {|v| compare( Functions::number(v), op, b )} else #puts "Functions::string( #{b}(#{b.class.name}) ) = #{Functions::string(b)}" b = Functions::string( b ) return a.collect { |v| compare( Functions::string(v), op, b ) } end else # If neither is nodeset, # If op is = or != # If either boolean, convert to boolean # If either number, convert to number # Else, convert to string # Else # Convert both to numbers and compare s1 = set1.to_s s2 = set2.to_s #puts "EQ_REL_COMP: #{set1}=>#{s1}, #{set2}=>#{s2}" if s1 == 'true' or s1 == 'false' or s2 == 'true' or s2 == 'false' #puts "Functions::boolean(#{set1})=>#{Functions::boolean(set1)}" #puts "Functions::boolean(#{set2})=>#{Functions::boolean(set2)}" set1 = Functions::boolean( set1 ) set2 = Functions::boolean( set2 ) else if op == :eq or op == :neq if s1 =~ /^\d+(\.\d+)?$/ or s2 =~ /^\d+(\.\d+)?$/ set1 = Functions::number( s1 ) set2 = Functions::number( s2 ) else set1 = Functions::string( set1 ) set2 = Functions::string( set2 ) end else set1 = Functions::number( set1 ) set2 = Functions::number( set2 ) end end #puts "EQ_REL_COMP: #{set1} #{op} #{set2}" #puts ">>> #{compare( set1, op, set2 )}" return compare( set1, op, set2 ) end return false end def compare a, op, b #puts "COMPARE #{a.inspect}(#{a.class.name}) #{op} #{b.inspect}(#{b.class.name})" case op when :eq a == b when :neq a != b when :lt a < b when :lteq a <= b when :gt a > b when :gteq a >= b when :and a and b when :or a or b else false end end end end