diff options
Diffstat (limited to 'actionpack/lib/action_view/vendor/html-scanner/html/node.rb')
| -rw-r--r-- | actionpack/lib/action_view/vendor/html-scanner/html/node.rb | 532 |
1 files changed, 532 insertions, 0 deletions
diff --git a/actionpack/lib/action_view/vendor/html-scanner/html/node.rb b/actionpack/lib/action_view/vendor/html-scanner/html/node.rb new file mode 100644 index 0000000000..4e1f016431 --- /dev/null +++ b/actionpack/lib/action_view/vendor/html-scanner/html/node.rb @@ -0,0 +1,532 @@ +require 'strscan' + +module HTML #:nodoc: + + class Conditions < Hash #:nodoc: + def initialize(hash) + super() + hash = { :content => hash } unless Hash === hash + hash = keys_to_symbols(hash) + hash.each do |k,v| + case k + when :tag, :content then + # keys are valid, and require no further processing + when :attributes then + hash[k] = keys_to_strings(v) + when :parent, :child, :ancestor, :descendant, :sibling, :before, + :after + hash[k] = Conditions.new(v) + when :children + hash[k] = v = keys_to_symbols(v) + v.each do |key,value| + case key + when :count, :greater_than, :less_than + # keys are valid, and require no further processing + when :only + v[key] = Conditions.new(value) + else + raise "illegal key #{key.inspect} => #{value.inspect}" + end + end + else + raise "illegal key #{k.inspect} => #{v.inspect}" + end + end + update hash + end + + private + + def keys_to_strings(hash) + Hash[hash.keys.map {|k| [k.to_s, hash[k]]}] + end + + def keys_to_symbols(hash) + Hash[hash.keys.map do |k| + raise "illegal key #{k.inspect}" unless k.respond_to?(:to_sym) + [k.to_sym, hash[k]] + end] + end + end + + # The base class of all nodes, textual and otherwise, in an HTML document. + class Node #:nodoc: + # The array of children of this node. Not all nodes have children. + attr_reader :children + + # The parent node of this node. All nodes have a parent, except for the + # root node. + attr_reader :parent + + # The line number of the input where this node was begun + attr_reader :line + + # The byte position in the input where this node was begun + attr_reader :position + + # Create a new node as a child of the given parent. + def initialize(parent, line=0, pos=0) + @parent = parent + @children = [] + @line, @position = line, pos + end + + # Return a textual representation of the node. + def to_s + @children.join() + end + + # Return false (subclasses must override this to provide specific matching + # behavior.) +conditions+ may be of any type. + def match(conditions) + false + end + + # Search the children of this node for the first node for which #find + # returns non +nil+. Returns the result of the #find call that succeeded. + def find(conditions) + conditions = validate_conditions(conditions) + @children.each do |child| + node = child.find(conditions) + return node if node + end + nil + end + + # Search for all nodes that match the given conditions, and return them + # as an array. + def find_all(conditions) + conditions = validate_conditions(conditions) + + matches = [] + matches << self if match(conditions) + @children.each do |child| + matches.concat child.find_all(conditions) + end + matches + end + + # Returns +false+. Subclasses may override this if they define a kind of + # tag. + def tag? + false + end + + def validate_conditions(conditions) + Conditions === conditions ? conditions : Conditions.new(conditions) + end + + def ==(node) + return false unless self.class == node.class && children.size == node.children.size + + equivalent = true + + children.size.times do |i| + equivalent &&= children[i] == node.children[i] + end + + equivalent + end + + class <<self + def parse(parent, line, pos, content, strict=true) + if content !~ /^<\S/ + Text.new(parent, line, pos, content) + else + scanner = StringScanner.new(content) + + unless scanner.skip(/</) + if strict + raise "expected <" + else + return Text.new(parent, line, pos, content) + end + end + + if scanner.skip(/!\[CDATA\[/) + unless scanner.skip_until(/\]\]>/) + if strict + raise "expected ]]> (got #{scanner.rest.inspect} for #{content})" + else + scanner.skip_until(/\Z/) + end + end + + return CDATA.new(parent, line, pos, scanner.pre_match.gsub(/<!\[CDATA\[/, '')) + end + + closing = ( scanner.scan(/\//) ? :close : nil ) + return Text.new(parent, line, pos, content) unless name = scanner.scan(/[^\s!>\/]+/) + name.downcase! + + unless closing + scanner.skip(/\s*/) + attributes = {} + while attr = scanner.scan(/[-\w:]+/) + value = true + if scanner.scan(/\s*=\s*/) + if delim = scanner.scan(/['"]/) + value = "" + while text = scanner.scan(/[^#{delim}\\]+|./) + case text + when "\\" then + value << text + break if scanner.eos? + value << scanner.getch + when delim + break + else value << text + end + end + else + value = scanner.scan(/[^\s>\/]+/) + end + end + attributes[attr.downcase] = value + scanner.skip(/\s*/) + end + + closing = ( scanner.scan(/\//) ? :self : nil ) + end + + unless scanner.scan(/\s*>/) + if strict + raise "expected > (got #{scanner.rest.inspect} for #{content}, #{attributes.inspect})" + else + # throw away all text until we find what we're looking for + scanner.skip_until(/>/) or scanner.terminate + end + end + + Tag.new(parent, line, pos, name, attributes, closing) + end + end + end + end + + # A node that represents text, rather than markup. + class Text < Node #:nodoc: + + attr_reader :content + + # Creates a new text node as a child of the given parent, with the given + # content. + def initialize(parent, line, pos, content) + super(parent, line, pos) + @content = content + end + + # Returns the content of this node. + def to_s + @content + end + + # Returns +self+ if this node meets the given conditions. Text nodes support + # conditions of the following kinds: + # + # * if +conditions+ is a string, it must be a substring of the node's + # content + # * if +conditions+ is a regular expression, it must match the node's + # content + # * if +conditions+ is a hash, it must contain a <tt>:content</tt> key that + # is either a string or a regexp, and which is interpreted as described + # above. + def find(conditions) + match(conditions) && self + end + + # Returns non-+nil+ if this node meets the given conditions, or +nil+ + # otherwise. See the discussion of #find for the valid conditions. + def match(conditions) + case conditions + when String + @content == conditions + when Regexp + @content =~ conditions + when Hash + conditions = validate_conditions(conditions) + + # Text nodes only have :content, :parent, :ancestor + unless (conditions.keys - [:content, :parent, :ancestor]).empty? + return false + end + + match(conditions[:content]) + else + nil + end + end + + def ==(node) + return false unless super + content == node.content + end + end + + # A CDATA node is simply a text node with a specialized way of displaying + # itself. + class CDATA < Text #:nodoc: + def to_s + "<![CDATA[#{super}]]>" + end + end + + # A Tag is any node that represents markup. It may be an opening tag, a + # closing tag, or a self-closing tag. It has a name, and may have a hash of + # attributes. + class Tag < Node #:nodoc: + + # Either +nil+, <tt>:close</tt>, or <tt>:self</tt> + attr_reader :closing + + # Either +nil+, or a hash of attributes for this node. + attr_reader :attributes + + # The name of this tag. + attr_reader :name + + # Create a new node as a child of the given parent, using the given content + # to describe the node. It will be parsed and the node name, attributes and + # closing status extracted. + def initialize(parent, line, pos, name, attributes, closing) + super(parent, line, pos) + @name = name + @attributes = attributes + @closing = closing + end + + # A convenience for obtaining an attribute of the node. Returns +nil+ if + # the node has no attributes. + def [](attr) + @attributes ? @attributes[attr] : nil + end + + # Returns non-+nil+ if this tag can contain child nodes. + def childless?(xml = false) + return false if xml && @closing.nil? + !@closing.nil? || + @name =~ /^(img|br|hr|link|meta|area|base|basefont| + col|frame|input|isindex|param)$/ox + end + + # Returns a textual representation of the node + def to_s + if @closing == :close + "</#{@name}>" + else + s = "<#{@name}" + @attributes.each do |k,v| + s << " #{k}" + s << "=\"#{v}\"" if String === v + end + s << " /" if @closing == :self + s << ">" + @children.each { |child| s << child.to_s } + s << "</#{@name}>" if @closing != :self && !@children.empty? + s + end + end + + # If either the node or any of its children meet the given conditions, the + # matching node is returned. Otherwise, +nil+ is returned. (See the + # description of the valid conditions in the +match+ method.) + def find(conditions) + match(conditions) && self || super + end + + # Returns +true+, indicating that this node represents an HTML tag. + def tag? + true + end + + # Returns +true+ if the node meets any of the given conditions. The + # +conditions+ parameter must be a hash of any of the following keys + # (all are optional): + # + # * <tt>:tag</tt>: the node name must match the corresponding value + # * <tt>:attributes</tt>: a hash. The node's values must match the + # corresponding values in the hash. + # * <tt>:parent</tt>: a hash. The node's parent must match the + # corresponding hash. + # * <tt>:child</tt>: a hash. At least one of the node's immediate children + # must meet the criteria described by the hash. + # * <tt>:ancestor</tt>: a hash. At least one of the node's ancestors must + # meet the criteria described by the hash. + # * <tt>:descendant</tt>: a hash. At least one of the node's descendants + # must meet the criteria described by the hash. + # * <tt>:sibling</tt>: a hash. At least one of the node's siblings must + # meet the criteria described by the hash. + # * <tt>:after</tt>: a hash. The node must be after any sibling meeting + # the criteria described by the hash, and at least one sibling must match. + # * <tt>:before</tt>: a hash. The node must be before any sibling meeting + # the criteria described by the hash, and at least one sibling must match. + # * <tt>:children</tt>: a hash, for counting children of a node. Accepts the + # keys: + # ** <tt>:count</tt>: either a number or a range which must equal (or + # include) the number of children that match. + # ** <tt>:less_than</tt>: the number of matching children must be less than + # this number. + # ** <tt>:greater_than</tt>: the number of matching children must be + # greater than this number. + # ** <tt>:only</tt>: another hash consisting of the keys to use + # to match on the children, and only matching children will be + # counted. + # + # Conditions are matched using the following algorithm: + # + # * if the condition is a string, it must be a substring of the value. + # * if the condition is a regexp, it must match the value. + # * if the condition is a number, the value must match number.to_s. + # * if the condition is +true+, the value must not be +nil+. + # * if the condition is +false+ or +nil+, the value must be +nil+. + # + # Usage: + # + # # test if the node is a "span" tag + # node.match :tag => "span" + # + # # test if the node's parent is a "div" + # node.match :parent => { :tag => "div" } + # + # # test if any of the node's ancestors are "table" tags + # node.match :ancestor => { :tag => "table" } + # + # # test if any of the node's immediate children are "em" tags + # node.match :child => { :tag => "em" } + # + # # test if any of the node's descendants are "strong" tags + # node.match :descendant => { :tag => "strong" } + # + # # test if the node has between 2 and 4 span tags as immediate children + # node.match :children => { :count => 2..4, :only => { :tag => "span" } } + # + # # get funky: test to see if the node is a "div", has a "ul" ancestor + # # and an "li" parent (with "class" = "enum"), and whether or not it has + # # a "span" descendant that contains # text matching /hello world/: + # node.match :tag => "div", + # :ancestor => { :tag => "ul" }, + # :parent => { :tag => "li", + # :attributes => { :class => "enum" } }, + # :descendant => { :tag => "span", + # :child => /hello world/ } + def match(conditions) + conditions = validate_conditions(conditions) + # check content of child nodes + if conditions[:content] + if children.empty? + return false unless match_condition("", conditions[:content]) + else + return false unless children.find { |child| child.match(conditions[:content]) } + end + end + + # test the name + return false unless match_condition(@name, conditions[:tag]) if conditions[:tag] + + # test attributes + (conditions[:attributes] || {}).each do |key, value| + return false unless match_condition(self[key], value) + end + + # test parent + return false unless parent.match(conditions[:parent]) if conditions[:parent] + + # test children + return false unless children.find { |child| child.match(conditions[:child]) } if conditions[:child] + + # test ancestors + if conditions[:ancestor] + return false unless catch :found do + p = self + throw :found, true if p.match(conditions[:ancestor]) while p = p.parent + end + end + + # test descendants + if conditions[:descendant] + return false unless children.find do |child| + # test the child + child.match(conditions[:descendant]) || + # test the child's descendants + child.match(:descendant => conditions[:descendant]) + end + end + + # count children + if opts = conditions[:children] + matches = children.select do |c| + (c.kind_of?(HTML::Tag) and (c.closing == :self or ! c.childless?)) + end + + matches = matches.select { |c| c.match(opts[:only]) } if opts[:only] + opts.each do |key, value| + next if key == :only + case key + when :count + if Integer === value + return false if matches.length != value + else + return false unless value.include?(matches.length) + end + when :less_than + return false unless matches.length < value + when :greater_than + return false unless matches.length > value + else raise "unknown count condition #{key}" + end + end + end + + # test siblings + if conditions[:sibling] || conditions[:before] || conditions[:after] + siblings = parent ? parent.children : [] + self_index = siblings.index(self) + + if conditions[:sibling] + return false unless siblings.detect do |s| + s != self && s.match(conditions[:sibling]) + end + end + + if conditions[:before] + return false unless siblings[self_index+1..-1].detect do |s| + s != self && s.match(conditions[:before]) + end + end + + if conditions[:after] + return false unless siblings[0,self_index].detect do |s| + s != self && s.match(conditions[:after]) + end + end + end + + true + end + + def ==(node) + return false unless super + return false unless closing == node.closing && self.name == node.name + attributes == node.attributes + end + + private + # Match the given value to the given condition. + def match_condition(value, condition) + case condition + when String + value && value == condition + when Regexp + value && value.match(condition) + when Numeric + value == condition.to_s + when true + !value.nil? + when false, nil + value.nil? + else + false + end + end + end +end |