Current File : //opt/alt/ruby27/share/ruby/rexml/xpath_parser.rb
# frozen_string_literal: false
require "pp"
require_relative 'namespace'
require_relative 'xmltokens'
require_relative 'attribute'
require_relative 'parsers/xpathparser'
class Object
# provides a unified +clone+ operation, for REXML::XPathParser
# to use across multiple Object types
def dclone
clone
end
end
class Symbol
# provides a unified +clone+ operation, for REXML::XPathParser
# to use across multiple Object types
def dclone ; self ; end
end
class Integer
# provides a unified +clone+ operation, for REXML::XPathParser
# to use across multiple Object types
def dclone ; self ; end
end
class Float
# provides a unified +clone+ operation, for REXML::XPathParser
# to use across multiple Object types
def dclone ; self ; end
end
class Array
# provides a unified +clone+ operation, for REXML::XPathParser
# to use across multiple Object+ types
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
DEBUG = (ENV["REXML_XPATH_PARSER_DEBUG"] == "true")
def initialize(strict: false)
@debug = DEBUG
@parser = REXML::Parsers::XPathParser.new
@namespaces = nil
@variables = {}
@nest = 0
@strict = strict
end
def namespaces=( namespaces={} )
Functions::namespace_context = namespaces
@namespaces = namespaces
end
def variables=( vars={} )
Functions::variables = vars
@variables = vars
end
def parse path, nodeset
path_stack = @parser.parse( path )
match( path_stack, nodeset )
end
def get_first path, nodeset
path_stack = @parser.parse( path )
first( path_stack, nodeset )
end
def predicate path, nodeset
path_stack = @parser.parse( path )
match( 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 )
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
r = first( path[1..-1], c )
return r if r
end
when :qname
name = path[2]
if node.name == name
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)
nodeset = nodeset.collect.with_index do |node, i|
position = i + 1
XPathNode.new(node, position: position)
end
result = expr(path_stack, nodeset)
case result
when Array # nodeset
unnode(result)
else
[result]
end
end
private
def strict?
@strict
end
# 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
def expr( path_stack, nodeset, context=nil )
enter(:expr, path_stack, nodeset) if @debug
return nodeset if path_stack.length == 0 || nodeset.length == 0
while path_stack.length > 0
trace(:while, path_stack, nodeset) if @debug
if nodeset.length == 0
path_stack.clear
return []
end
op = path_stack.shift
case op
when :document
first_raw_node = nodeset.first.raw_node
nodeset = [XPathNode.new(first_raw_node.root_node, position: 1)]
when :self
nodeset = step(path_stack) do
[nodeset]
end
when :child
nodeset = step(path_stack) do
child(nodeset)
end
when :literal
trace(:literal, path_stack, nodeset) if @debug
return path_stack.shift
when :attribute
nodeset = step(path_stack, any_type: :attribute) do
nodesets = []
nodeset.each do |node|
raw_node = node.raw_node
next unless raw_node.node_type == :element
attributes = raw_node.attributes
next if attributes.empty?
nodesets << attributes.each_attribute.collect.with_index do |attribute, i|
XPathNode.new(attribute, position: i + 1)
end
end
nodesets
end
when :namespace
pre_defined_namespaces = {
"xml" => "http://www.w3.org/XML/1998/namespace",
}
nodeset = step(path_stack, any_type: :namespace) do
nodesets = []
nodeset.each do |node|
raw_node = node.raw_node
case raw_node.node_type
when :element
if @namespaces
nodesets << pre_defined_namespaces.merge(@namespaces)
else
nodesets << pre_defined_namespaces.merge(raw_node.namespaces)
end
when :attribute
if @namespaces
nodesets << pre_defined_namespaces.merge(@namespaces)
else
nodesets << pre_defined_namespaces.merge(raw_node.element.namespaces)
end
end
end
nodesets
end
when :parent
nodeset = step(path_stack) do
nodesets = []
nodeset.each do |node|
raw_node = node.raw_node
if raw_node.node_type == :attribute
parent = raw_node.element
else
parent = raw_node.parent
end
nodesets << [XPathNode.new(parent, position: 1)] if parent
end
nodesets
end
when :ancestor
nodeset = step(path_stack) do
nodesets = []
# new_nodes = {}
nodeset.each do |node|
raw_node = node.raw_node
new_nodeset = []
while raw_node.parent
raw_node = raw_node.parent
# next if new_nodes.key?(node)
new_nodeset << XPathNode.new(raw_node,
position: new_nodeset.size + 1)
# new_nodes[node] = true
end
nodesets << new_nodeset unless new_nodeset.empty?
end
nodesets
end
when :ancestor_or_self
nodeset = step(path_stack) do
nodesets = []
# new_nodes = {}
nodeset.each do |node|
raw_node = node.raw_node
next unless raw_node.node_type == :element
new_nodeset = [XPathNode.new(raw_node, position: 1)]
# new_nodes[node] = true
while raw_node.parent
raw_node = raw_node.parent
# next if new_nodes.key?(node)
new_nodeset << XPathNode.new(raw_node,
position: new_nodeset.size + 1)
# new_nodes[node] = true
end
nodesets << new_nodeset unless new_nodeset.empty?
end
nodesets
end
when :descendant_or_self
nodeset = step(path_stack) do
descendant(nodeset, true)
end
when :descendant
nodeset = step(path_stack) do
descendant(nodeset, false)
end
when :following_sibling
nodeset = step(path_stack) do
nodesets = []
nodeset.each do |node|
raw_node = node.raw_node
next unless raw_node.respond_to?(:parent)
next if raw_node.parent.nil?
all_siblings = raw_node.parent.children
current_index = all_siblings.index(raw_node)
following_siblings = all_siblings[(current_index + 1)..-1]
next if following_siblings.empty?
nodesets << following_siblings.collect.with_index do |sibling, i|
XPathNode.new(sibling, position: i + 1)
end
end
nodesets
end
when :preceding_sibling
nodeset = step(path_stack, order: :reverse) do
nodesets = []
nodeset.each do |node|
raw_node = node.raw_node
next unless raw_node.respond_to?(:parent)
next if raw_node.parent.nil?
all_siblings = raw_node.parent.children
current_index = all_siblings.index(raw_node)
preceding_siblings = all_siblings[0, current_index].reverse
next if preceding_siblings.empty?
nodesets << preceding_siblings.collect.with_index do |sibling, i|
XPathNode.new(sibling, position: i + 1)
end
end
nodesets
end
when :preceding
nodeset = step(path_stack, order: :reverse) do
unnode(nodeset) do |node|
preceding(node)
end
end
when :following
nodeset = step(path_stack) do
unnode(nodeset) do |node|
following(node)
end
end
when :variable
var_name = path_stack.shift
return [@variables[var_name]]
when :eq, :neq, :lt, :lteq, :gt, :gteq
left = expr( path_stack.shift, nodeset.dup, context )
right = expr( path_stack.shift, nodeset.dup, context )
res = equality_relational_compare( left, op, right )
trace(op, left, right, res) if @debug
return res
when :or
left = expr(path_stack.shift, nodeset.dup, context)
return true if Functions.boolean(left)
right = expr(path_stack.shift, nodeset.dup, context)
return Functions.boolean(right)
when :and
left = expr(path_stack.shift, nodeset.dup, context)
return false unless Functions.boolean(left)
right = expr(path_stack.shift, nodeset.dup, context)
return Functions.boolean(right)
when :div, :mod, :mult, :plus, :minus
left = expr(path_stack.shift, nodeset, context)
right = expr(path_stack.shift, nodeset, context)
left = unnode(left) if left.is_a?(Array)
right = unnode(right) if right.is_a?(Array)
left = Functions::number(left)
right = Functions::number(right)
case op
when :div
return left / right
when :mod
return left % right
when :mult
return left * right
when :plus
return left + right
when :minus
return left - right
else
raise "[BUG] Unexpected operator: <#{op.inspect}>"
end
when :union
left = expr( path_stack.shift, nodeset, context )
right = expr( path_stack.shift, nodeset, context )
left = unnode(left) if left.is_a?(Array)
right = unnode(right) if right.is_a?(Array)
return (left | right)
when :neg
res = expr( path_stack, nodeset, context )
res = unnode(res) if res.is_a?(Array)
return -Functions.number(res)
when :not
when :function
func_name = path_stack.shift.tr('-','_')
arguments = path_stack.shift
if nodeset.size != 1
message = "[BUG] Node set size must be 1 for function call: "
message += "<#{func_name}>: <#{nodeset.inspect}>: "
message += "<#{arguments.inspect}>"
raise message
end
node = nodeset.first
if context
target_context = context
else
target_context = {:size => nodeset.size}
if node.is_a?(XPathNode)
target_context[:node] = node.raw_node
target_context[:index] = node.position
else
target_context[:node] = node
target_context[:index] = 1
end
end
args = arguments.dclone.collect do |arg|
result = expr(arg, nodeset, target_context)
result = unnode(result) if result.is_a?(Array)
result
end
Functions.context = target_context
return Functions.send(func_name, *args)
else
raise "[BUG] Unexpected path: <#{op.inspect}>: <#{path_stack.inspect}>"
end
end # while
return nodeset
ensure
leave(:expr, path_stack, nodeset) if @debug
end
def step(path_stack, any_type: :element, order: :forward)
nodesets = yield
begin
enter(:step, path_stack, nodesets) if @debug
nodesets = node_test(path_stack, nodesets, any_type: any_type)
while path_stack[0] == :predicate
path_stack.shift # :predicate
predicate_expression = path_stack.shift.dclone
nodesets = evaluate_predicate(predicate_expression, nodesets)
end
if nodesets.size == 1
ordered_nodeset = nodesets[0]
else
raw_nodes = []
nodesets.each do |nodeset|
nodeset.each do |node|
if node.respond_to?(:raw_node)
raw_nodes << node.raw_node
else
raw_nodes << node
end
end
end
ordered_nodeset = sort(raw_nodes, order)
end
new_nodeset = []
ordered_nodeset.each do |node|
# TODO: Remove duplicated
new_nodeset << XPathNode.new(node, position: new_nodeset.size + 1)
end
new_nodeset
ensure
leave(:step, path_stack, new_nodeset) if @debug
end
end
def node_test(path_stack, nodesets, any_type: :element)
enter(:node_test, path_stack, nodesets) if @debug
operator = path_stack.shift
case operator
when :qname
prefix = path_stack.shift
name = path_stack.shift
new_nodesets = nodesets.collect do |nodeset|
filter_nodeset(nodeset) do |node|
raw_node = node.raw_node
case raw_node.node_type
when :element
if prefix.nil?
raw_node.name == name
elsif prefix.empty?
if strict?
raw_node.name == name and raw_node.namespace == ""
else
# FIXME: This DOUBLES the time XPath searches take
ns = get_namespace(raw_node, prefix)
raw_node.name == name and raw_node.namespace == ns
end
else
# FIXME: This DOUBLES the time XPath searches take
ns = get_namespace(raw_node, prefix)
raw_node.name == name and raw_node.namespace == ns
end
when :attribute
if prefix.nil?
raw_node.name == name
elsif prefix.empty?
raw_node.name == name and raw_node.namespace == ""
else
# FIXME: This DOUBLES the time XPath searches take
ns = get_namespace(raw_node.element, prefix)
raw_node.name == name and raw_node.namespace == ns
end
else
false
end
end
end
when :namespace
prefix = path_stack.shift
new_nodesets = nodesets.collect do |nodeset|
filter_nodeset(nodeset) do |node|
raw_node = node.raw_node
case raw_node.node_type
when :element
namespaces = @namespaces || raw_node.namespaces
raw_node.namespace == namespaces[prefix]
when :attribute
namespaces = @namespaces || raw_node.element.namespaces
raw_node.namespace == namespaces[prefix]
else
false
end
end
end
when :any
new_nodesets = nodesets.collect do |nodeset|
filter_nodeset(nodeset) do |node|
raw_node = node.raw_node
raw_node.node_type == any_type
end
end
when :comment
new_nodesets = nodesets.collect do |nodeset|
filter_nodeset(nodeset) do |node|
raw_node = node.raw_node
raw_node.node_type == :comment
end
end
when :text
new_nodesets = nodesets.collect do |nodeset|
filter_nodeset(nodeset) do |node|
raw_node = node.raw_node
raw_node.node_type == :text
end
end
when :processing_instruction
target = path_stack.shift
new_nodesets = nodesets.collect do |nodeset|
filter_nodeset(nodeset) do |node|
raw_node = node.raw_node
(raw_node.node_type == :processing_instruction) and
(target.empty? or (raw_node.target == target))
end
end
when :node
new_nodesets = nodesets.collect do |nodeset|
filter_nodeset(nodeset) do |node|
true
end
end
else
message = "[BUG] Unexpected node test: " +
"<#{operator.inspect}>: <#{path_stack.inspect}>"
raise message
end
new_nodesets
ensure
leave(:node_test, path_stack, new_nodesets) if @debug
end
def filter_nodeset(nodeset)
new_nodeset = []
nodeset.each do |node|
next unless yield(node)
new_nodeset << XPathNode.new(node, position: new_nodeset.size + 1)
end
new_nodeset
end
def evaluate_predicate(expression, nodesets)
enter(:predicate, expression, nodesets) if @debug
new_nodesets = nodesets.collect do |nodeset|
new_nodeset = []
subcontext = { :size => nodeset.size }
nodeset.each_with_index do |node, index|
if node.is_a?(XPathNode)
subcontext[:node] = node.raw_node
subcontext[:index] = node.position
else
subcontext[:node] = node
subcontext[:index] = index + 1
end
result = expr(expression.dclone, [node], subcontext)
trace(:predicate_evaluate, expression, node, subcontext, result) if @debug
result = result[0] if result.kind_of? Array and result.length == 1
if result.kind_of? Numeric
if result == node.position
new_nodeset << XPathNode.new(node, position: new_nodeset.size + 1)
end
elsif result.instance_of? Array
if result.size > 0 and result.inject(false) {|k,s| s or k}
if result.size > 0
new_nodeset << XPathNode.new(node, position: new_nodeset.size + 1)
end
end
else
if result
new_nodeset << XPathNode.new(node, position: new_nodeset.size + 1)
end
end
end
new_nodeset
end
new_nodesets
ensure
leave(:predicate, new_nodesets) if @debug
end
def trace(*args)
indent = " " * @nest
PP.pp(args, "").each_line do |line|
puts("#{indent}#{line}")
end
end
def enter(tag, *args)
trace(:enter, tag, *args)
@nest += 1
end
def leave(tag, *args)
@nest -= 1
trace(:leave, tag, *args)
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 sort(array_of_nodes, order)
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 ]
}
ordered = new_arry.sort_by do |index, node|
if order == :forward
index
else
-index
end
end
ordered.collect do |_index, node|
node
end
end
def descendant(nodeset, include_self)
nodesets = []
nodeset.each do |node|
new_nodeset = []
new_nodes = {}
descendant_recursive(node.raw_node, new_nodeset, new_nodes, include_self)
nodesets << new_nodeset unless new_nodeset.empty?
end
nodesets
end
def descendant_recursive(raw_node, new_nodeset, new_nodes, include_self)
if include_self
return if new_nodes.key?(raw_node)
new_nodeset << XPathNode.new(raw_node, position: new_nodeset.size + 1)
new_nodes[raw_node] = true
end
node_type = raw_node.node_type
if node_type == :element or node_type == :document
raw_node.children.each do |child|
descendant_recursive(child, new_nodeset, new_nodes, true)
end
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)
ancestors = []
parent = node.parent
while parent
ancestors << parent
parent = parent.parent
end
precedings = []
preceding_node = preceding_node_of(node)
while preceding_node
if ancestors.include?(preceding_node)
ancestors.delete(preceding_node)
else
precedings << XPathNode.new(preceding_node,
position: precedings.size + 1)
end
preceding_node = preceding_node_of(preceding_node)
end
precedings
end
def preceding_node_of( node )
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)
followings = []
following_node = next_sibling_node(node)
while following_node
followings << XPathNode.new(following_node,
position: followings.size + 1)
following_node = following_node_of(following_node)
end
followings
end
def following_node_of( node )
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
end
return psn
end
def child(nodeset)
nodesets = []
nodeset.each do |node|
raw_node = node.raw_node
node_type = raw_node.node_type
# trace(:child, node_type, node)
case node_type
when :element
nodesets << raw_node.children.collect.with_index do |child_node, i|
XPathNode.new(child_node, position: i + 1)
end
when :document
new_nodeset = []
raw_node.children.each do |child|
case child
when XMLDecl, Text
# Ignore
else
new_nodeset << XPathNode.new(child, position: new_nodeset.size + 1)
end
end
nodesets << new_nodeset unless new_nodeset.empty?
end
end
nodesets
end
def norm b
case b
when true, false
return b
when 'true', 'false'
return Functions::boolean( b )
when /^\d+(\.\d+)?$/, Numeric
return Functions::number( b )
else
return Functions::string( b )
end
end
def equality_relational_compare(set1, op, set2)
set1 = unnode(set1) if set1.is_a?(Array)
set2 = unnode(set2) if set2.is_a?(Array)
if set1.kind_of? Array and set2.kind_of? Array
# If both objects to be compared are node-sets, then the
# comparison will be true if and only if there is a node in the
# first node-set and a node in the second node-set such that the
# result of performing the comparison on the string-values of
# the two nodes is true.
set1.product(set2).any? do |node1, node2|
node_string1 = Functions.string(node1)
node_string2 = Functions.string(node2)
compare(node_string1, op, node_string2)
end
elsif set1.kind_of? Array or set2.kind_of? Array
# 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
a = set1
b = set2
else
a = set2
b = set1
end
case b
when true, false
each_unnode(a).any? do |unnoded|
compare(Functions.boolean(unnoded), op, b)
end
when Numeric
each_unnode(a).any? do |unnoded|
compare(Functions.number(unnoded), op, b)
end
when /\A\d+(\.\d+)?\z/
b = Functions.number(b)
each_unnode(a).any? do |unnoded|
compare(Functions.number(unnoded), op, b)
end
else
b = Functions::string(b)
each_unnode(a).any? do |unnoded|
compare(Functions::string(unnoded), op, b)
end
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
compare(set1, op, set2)
end
end
def value_type(value)
case value
when true, false
:boolean
when Numeric
:number
when String
:string
else
raise "[BUG] Unexpected value type: <#{value.inspect}>"
end
end
def normalize_compare_values(a, operator, b)
a_type = value_type(a)
b_type = value_type(b)
case operator
when :eq, :neq
if a_type == :boolean or b_type == :boolean
a = Functions.boolean(a) unless a_type == :boolean
b = Functions.boolean(b) unless b_type == :boolean
elsif a_type == :number or b_type == :number
a = Functions.number(a) unless a_type == :number
b = Functions.number(b) unless b_type == :number
else
a = Functions.string(a) unless a_type == :string
b = Functions.string(b) unless b_type == :string
end
when :lt, :lteq, :gt, :gteq
a = Functions.number(a) unless a_type == :number
b = Functions.number(b) unless b_type == :number
else
message = "[BUG] Unexpected compare operator: " +
"<#{operator.inspect}>: <#{a.inspect}>: <#{b.inspect}>"
raise message
end
[a, b]
end
def compare(a, operator, b)
a, b = normalize_compare_values(a, operator, b)
case operator
when :eq
a == b
when :neq
a != b
when :lt
a < b
when :lteq
a <= b
when :gt
a > b
when :gteq
a >= b
else
message = "[BUG] Unexpected compare operator: " +
"<#{operator.inspect}>: <#{a.inspect}>: <#{b.inspect}>"
raise message
end
end
def each_unnode(nodeset)
return to_enum(__method__, nodeset) unless block_given?
nodeset.each do |node|
if node.is_a?(XPathNode)
unnoded = node.raw_node
else
unnoded = node
end
yield(unnoded)
end
end
def unnode(nodeset)
each_unnode(nodeset).collect do |unnoded|
unnoded = yield(unnoded) if block_given?
unnoded
end
end
end
# @private
class XPathNode
attr_reader :raw_node, :context
def initialize(node, context=nil)
if node.is_a?(XPathNode)
@raw_node = node.raw_node
else
@raw_node = node
end
@context = context || {}
end
def position
@context[:position]
end
end
end