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!
# File tmp/rubies/ruby-2.6.10/lib/rexml/xpath_parser.rb, line 50
def initialize(strict: false)
@parser = REXML::Parsers::XPathParser.new
@namespaces = nil
@variables = {}
@nest = 0
@strict = strict
end
# File tmp/rubies/ruby-2.6.10/lib/rexml/xpath_parser.rb, line 83
def []=( variable_name, value )
@variables[ variable_name ] = value
end
# File tmp/rubies/ruby-2.6.10/lib/rexml/xpath_parser.rb, line 763
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
# File tmp/rubies/ruby-2.6.10/lib/rexml/xpath_parser.rb, line 882
def compare a, op, b
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
# File tmp/rubies/ruby-2.6.10/lib/rexml/xpath_parser.rb, line 666
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
# File tmp/rubies/ruby-2.6.10/lib/rexml/xpath_parser.rb, line 677
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
# File tmp/rubies/ruby-2.6.10/lib/rexml/xpath_parser.rb, line 625
def enter(tag, *args)
trace(:enter, tag, *args)
@nest += 1
end
# File tmp/rubies/ruby-2.6.10/lib/rexml/xpath_parser.rb, line 803
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 set1.size == 0 or set2.size == 0
nd = set1.size==0 ? set2 : set1
rv = nd.collect { |il| compare( il, op, nil ) }
return rv
else
res = []
SyncEnumerator.new( set1, set2 ).each { |i1, i2|
i1 = norm( i1 )
i2 = norm( i2 )
res << compare( i1, op, i2 )
}
return res
end
end
# 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
if set1.kind_of? Array
a = set1
b = set2
else
a = set2
b = set1
end
case b
when true, false
return unnode(a) {|v| compare( Functions::boolean(v), op, b ) }
when Numeric
return unnode(a) {|v| compare( Functions::number(v), op, b )}
when /^\d+(\.\d+)?$/
b = Functions::number( b )
return unnode(a) {|v| compare( Functions::number(v), op, b )}
else
b = Functions::string( b )
return unnode(a) { |v| compare( Functions::string(v), op, b ) }
end
else
# If neither is nodeset,
# If op is = or !=
# If either boolean, convert to boolean
# If either number, convert to number
# Else, convert to string
# Else
# Convert both to numbers and compare
set1 = unnode(set1) if set1.is_a?(Array)
set2 = unnode(set2) if set2.is_a?(Array)
s1 = Functions.string(set1)
s2 = Functions.string(set2)
if s1 == 'true' or s1 == 'false' or s2 == 'true' or s2 == 'false'
set1 = Functions::boolean( set1 )
set2 = Functions::boolean( set2 )
else
if op == :eq or op == :neq
if s1 =~ /^\d+(\.\d+)?$/ 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
return compare( set1, op, set2 )
end
return false
end
# File tmp/rubies/ruby-2.6.10/lib/rexml/xpath_parser.rb, line 581
def evaluate_predicate(expression, nodesets)
# enter(:predicate, expression, nodesets)
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)
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)
end
# File tmp/rubies/ruby-2.6.10/lib/rexml/xpath_parser.rb, line 164
def expr( path_stack, nodeset, context=nil )
# enter(:expr, path_stack, nodeset)
return nodeset if path_stack.length == 0 || nodeset.length == 0
while path_stack.length > 0
# trace(:while, path_stack, nodeset)
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)
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]]
# :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, :or
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)
return res
when :and
left = expr( path_stack.shift, nodeset.dup, context )
return [] unless left
if left.respond_to?(:inject) and !left.inject(false) {|a,b| a | b}
return []
end
right = expr( path_stack.shift, nodeset.dup, context )
res = equality_relational_compare( left, op, right )
return res
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
subcontext = context ? nil : { :size => nodeset.size }
res = []
cont = context
nodeset.each_with_index do |node, i|
if subcontext
if node.is_a?(XPathNode)
subcontext[:node] = node.raw_node
subcontext[:index] = node.position
else
subcontext[:node] = node
subcontext[:index] = i
end
cont = subcontext
end
arg_clone = arguments.dclone
args = arg_clone.collect do |arg|
result = expr( arg, [node], cont )
result = unnode(result) if result.is_a?(Array)
result
end
Functions.context = cont
res << Functions.send( func_name, *args )
end
return res
else
raise "[BUG] Unexpected path: <#{op.inspect}>: <#{path_stack.inspect}>"
end
end # while
return nodeset
# ensure
# leave(:expr, path_stack, nodeset)
end
# File tmp/rubies/ruby-2.6.10/lib/rexml/xpath_parser.rb, line 572
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
# File tmp/rubies/ruby-2.6.10/lib/rexml/xpath_parser.rb, line 92
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
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!
# File tmp/rubies/ruby-2.6.10/lib/rexml/xpath_parser.rb, line 733
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
# File tmp/rubies/ruby-2.6.10/lib/rexml/xpath_parser.rb, line 744
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
# File tmp/rubies/ruby-2.6.10/lib/rexml/xpath_parser.rb, line 73
def get_first path, nodeset
path_stack = @parser.parse( path )
first( path_stack, nodeset )
end
# File tmp/rubies/ruby-2.6.10/lib/rexml/xpath_parser.rb, line 152
def get_namespace( node, prefix )
if @namespaces
return @namespaces[prefix] || ''
else
return node.namespace( prefix ) if node.node_type == :element
return ''
end
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
# File tmp/rubies/ruby-2.6.10/lib/rexml/xpath_parser.rb, line 630
def leave(tag, *args)
@nest -= 1
trace(:leave, tag, *args)
end
# File tmp/rubies/ruby-2.6.10/lib/rexml/xpath_parser.rb, line 128
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
# File tmp/rubies/ruby-2.6.10/lib/rexml/xpath_parser.rb, line 58
def namespaces=( namespaces={} )
Functions::namespace_context = namespaces
@namespaces = namespaces
end
# File tmp/rubies/ruby-2.6.10/lib/rexml/xpath_parser.rb, line 751
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
# File tmp/rubies/ruby-2.6.10/lib/rexml/xpath_parser.rb, line 465
def node_test(path_stack, nodesets, any_type: :element)
# enter(:node_test, path_stack, nodesets)
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?
# FIXME: This DOUBLES the time XPath searches take
raw_node.name == name and
raw_node.namespace == raw_node.element.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)
end
# File tmp/rubies/ruby-2.6.10/lib/rexml/xpath_parser.rb, line 790
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
# File tmp/rubies/ruby-2.6.10/lib/rexml/xpath_parser.rb, line 68
def parse path, nodeset
path_stack = @parser.parse( path )
match( path_stack, nodeset )
end
# File tmp/rubies/ruby-2.6.10/lib/rexml/xpath_parser.rb, line 696
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
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
# File tmp/rubies/ruby-2.6.10/lib/rexml/xpath_parser.rb, line 718
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
# File tmp/rubies/ruby-2.6.10/lib/rexml/xpath_parser.rb, line 78
def predicate path, nodeset
path_stack = @parser.parse( path )
match( path_stack, nodeset )
end
# File tmp/rubies/ruby-2.6.10/lib/rexml/xpath_parser.rb, line 643
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
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.
# File tmp/rubies/ruby-2.6.10/lib/rexml/xpath_parser.rb, line 429
def step(path_stack, any_type: :element, order: :forward)
nodesets = yield
begin
# enter(:step, path_stack, nodesets)
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)
end
end
# File tmp/rubies/ruby-2.6.10/lib/rexml/xpath_parser.rb, line 143
def strict?
@strict
end
# File tmp/rubies/ruby-2.6.10/lib/rexml/xpath_parser.rb, line 620
def trace(*args)
indent = " " * @nest
puts("#{indent}#{args.inspect}")
end
# File tmp/rubies/ruby-2.6.10/lib/rexml/xpath_parser.rb, line 905
def unnode(nodeset)
nodeset.collect do |node|
if node.is_a?(XPathNode)
unnoded = node.raw_node
else
unnoded = node
end
unnoded = yield(unnoded) if block_given?
unnoded
end
end
# File tmp/rubies/ruby-2.6.10/lib/rexml/xpath_parser.rb, line 63
def variables=( vars={} )
Functions::variables = vars
@variables = vars
end