--- /dev/null
+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 |k,v2|
+ case k
+ when :count, :greater_than, :less_than
+ # keys are valid, and require no further processing
+ when :only
+ v[k] = Conditions.new(v2)
+ else
+ raise "illegal key #{k.inspect} => #{v2.inspect}"
+ end
+ end
+ else
+ raise "illegal key #{k.inspect} => #{v.inspect}"
+ end
+ end
+ update hash
+ end
+
+ private
+
+ def keys_to_strings(hash)
+ hash.keys.inject({}) do |h,k|
+ h[k.to_s] = hash[k]
+ h
+ end
+ end
+
+ def keys_to_symbols(hash)
+ hash.keys.inject({}) do |h,k|
+ raise "illegal key #{k.inspect}" unless k.respond_to?(:to_sym)
+ h[k.to_sym] = hash[k]
+ h
+ 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
+ s = ""
+ @children.each { |child| s << child.to_s }
+ s
+ 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(/[\w:-]+/)
+ 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
+ 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
projects / depot.git / blobdiff