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authorser <ser@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>2003-06-10 01:31:01 +0000
committerser <ser@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>2003-06-10 01:31:01 +0000
commitea7a527a2ae7024a5cf2885dee8f7a5c21fedd5d (patch)
treed3e1f95a5acf262a9dd46e9663b7034bb285b406 /lib/rexml/element.rb
parentca02190d8887ecd852e4e3f18f3a3ea91e9c6f7a (diff)
Initial revision
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@3925 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
Diffstat (limited to 'lib/rexml/element.rb')
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diff --git a/lib/rexml/element.rb b/lib/rexml/element.rb
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+require "rexml/parent"
+require "rexml/namespace"
+require "rexml/attribute"
+require "rexml/cdata"
+require "rexml/xpath"
+require "rexml/parseexception"
+
+module REXML
+ # Represents a tagged XML element. Elements are characterized by
+ # having children, attributes, and names, and can themselves be
+ # children.
+ class Element < Parent
+ include Namespace
+
+ UNDEFINED = "UNDEFINED"; # The default name
+
+ # Mechanisms for accessing attributes and child elements of this
+ # element.
+ attr_reader :attributes, :elements
+ # The context holds information about the processing environment, such as
+ # whitespace handling.
+ attr_accessor :context
+
+ # Constructor
+ # arg::
+ # if not supplied, will be set to the default value.
+ # If a String, the name of this object will be set to the argument.
+ # If an Element, the object will be shallowly cloned; name,
+ # attributes, and namespaces will be copied. Children will +not+ be
+ # copied.
+ # If a Source, the source will be scanned and parsed for an Element,
+ # and all child elements will be recursively parsed as well.
+ # parent::
+ # if supplied, must be a Parent, and will be used as
+ # the parent of this object.
+ # context::
+ # If supplied, must be a hash containing context items. Context items
+ # include:
+ # * <tt>:respect_whitespace</tt> the value of this is :+all+ or an array of
+ # strings being the names of the elements to respect
+ # whitespace for. Defaults to :+all+.
+ # * <tt>:compress_whitespace</tt> the value can be :+all+ or an array of
+ # strings being the names of the elements to ignore whitespace on.
+ # Overrides :+respect_whitespace+.
+ # * <tt>:ignore_whitespace_nodes</tt> the value can be :+all+ or an array
+ # of strings being the names of the elements in which to ignore
+ # whitespace-only nodes. If this is set, Text nodes which contain only
+ # whitespace will not be added to the document tree.
+ # * <tt>:raw</tt> can be :+all+, or an array of strings being the names of
+ # the elements to process in raw mode. In raw mode, special
+ # characters in text is not converted to or from entities.
+ def initialize( arg = UNDEFINED, parent=nil, context=nil )
+ super(parent)
+
+ @elements = Elements.new self
+ @attributes = Attributes.new self
+ @context = context
+
+ if arg.kind_of? String
+ self.name = arg
+ elsif arg.kind_of? Element
+ self.name = arg.expanded_name
+ arg.attributes.each_attribute{ |attribute|
+ @attributes << Attribute.new( attribute )
+ }
+ @context = arg.context
+ end
+ end
+
+ # Creates a shallow copy of self.
+ # d = Document.new "<a><b/><b/><c><d/></c></a>"
+ # new_a = d.root.clone
+ # puts new_a # => "<a/>"
+ def clone
+ Element.new self
+ end
+
+ # Evaluates to the root element of the document that this element
+ # belongs to. If this element doesn't belong to a document, but does
+ # belong to another Element, the parent's root will be returned, until the
+ # earliest ancestor is found.
+ # d = Document.new '<a><b><c/></b></a>'
+ # a = d[1] ; c = a[1][1]
+ # d.root # These all evaluate to the same Element,
+ # a.root # namely, <a>
+ # c.root #
+ def root
+ parent.nil? ? self : parent.root
+ end
+
+ # Evaluates to the document to which this element belongs, or nil if this
+ # element doesn't belong to a document.
+ def document
+ root.parent if root
+ end
+
+ # Evaluates to +true+ if whitespace is respected for this element. This
+ # is the case if:
+ # 1. Neither :+respect_whitespace+ nor :+compress_whitespace+ has any value
+ # 2. The context has :+respect_whitespace+ set to :+all+ or
+ # an array containing the name of this element, and :+compress_whitespace+
+ # isn't set to :+all+ or an array containing the name of this element.
+ # The evaluation is tested against +expanded_name+, and so is namespace
+ # sensitive.
+ def whitespace
+ @whitespace = nil
+ if @context
+ if @context[:respect_whitespace]
+ @whitespace = (@context[:respect_whitespace] == :all or
+ @context[:respect_whitespace].include? expanded_name)
+ end
+ @whitespace = false if (@context[:compress_whitespace] and
+ (@context[:compress_whitespace] == :all or
+ @context[:compress_whitespace].include? expanded_name)
+ )
+ end
+ @whitespace = true unless @whitespace == false
+ @whitespace
+ end
+
+ def ignore_whitespace_nodes
+ @ignore_whitespace_nodes = false
+ if @context
+ if @context[:ignore_whitespace_nodes]
+ @ignore_whitespace_nodes =
+ (@context[:ignore_whitespace_nodes] == :all or
+ @context[:ignore_whitespace_nodes].include? expanded_name)
+ end
+ end
+ end
+
+ # Evaluates to +true+ if raw mode is set for this element. This
+ # is the case if the context has :+raw+ set to :+all+ or
+ # an array containing the name of this element.
+ #
+ # The evaluation is tested against +expanded_name+, and so is namespace
+ # sensitive.
+ def raw
+ @raw = (@context and @context[:raw] and
+ (@context[:raw] == :all or
+ @context[:raw].include? expanded_name))
+ @raw
+ end
+
+ #once :whitespace, :raw, :ignore_whitespace_nodes
+
+ #################################################
+ # Namespaces #
+ #################################################
+
+ # Evaluates to an +Array+ containing the prefixes (names) of all defined
+ # namespaces at this context node.
+ # doc = Document.new("<a xmlns:x='1' xmlns:y='2'><b/><c xmlns:z='3'/></a>")
+ # doc.elements['//b'].prefixes # -> ['x', 'y']
+ def prefixes
+ prefixes = []
+ prefixes = parent.prefixes if parent
+ prefixes |= attributes.prefixes
+ return prefixes
+ end
+
+ def namespaces
+ namespaces = []
+ namespaces = parent.namespaces if parent
+ namespaces |= attributes.namespaces
+ return namespaces
+ end
+
+ # Evalutas to the URI for a prefix, or the empty string if no such
+ # namespace is declared for this element. Evaluates recursively for
+ # ancestors. Returns the default namespace, if there is one.
+ # prefix::
+ # the prefix to search for. If not supplied, returns the default
+ # namespace if one exists
+ # Returns::
+ # the namespace URI as a String, or nil if no such namespace
+ # exists. If the namespace is undefined, returns an empty string
+ # doc = Document.new("<a xmlns='1' xmlns:y='2'><b/><c xmlns:z='3'/></a>")
+ # b = doc.elements['//b']
+ # b.namespace # -> '1'
+ # b.namespace("y") # -> '2'
+ def namespace(prefix=nil)
+ if prefix.nil?
+ prefix = prefix()
+ end
+ if prefix == ''
+ prefix = "xmlns"
+ else
+ prefix = "xmlns:#{prefix}" unless prefix[0,5] == 'xmlns'
+ end
+ ns = attributes[ prefix ]
+ ns = parent.namespace(prefix) if ns.nil? and parent
+ ns = '' if ns.nil? and prefix == 'xmlns'
+ return ns
+ end
+
+ # Adds a namespace to this element.
+ # prefix::
+ # the prefix string, or the namespace URI if +uri+ is not
+ # supplied
+ # uri::
+ # the namespace URI. May be nil, in which +prefix+ is used as
+ # the URI
+ # Evaluates to: this Element
+ # a = Element.new("a")
+ # a.add_namespace("xmlns:foo", "bar" )
+ # a.add_namespace("foo", "bar") # shorthand for previous line
+ # a.add_namespace("twiddle")
+ # puts a #-> <a xmlns:foo='bar' xmlns='twiddle'/>
+ def add_namespace( prefix, uri=nil )
+ unless uri
+ @attributes["xmlns"] = prefix
+ else
+ prefix = "xmlns:#{prefix}" unless prefix =~ /^xmlns:/
+ @attributes[ prefix ] = uri
+ end
+ self
+ end
+
+ # Removes a namespace from this node. This only works if the namespace is
+ # actually declared in this node. If no argument is passed, deletes the
+ # default namespace.
+ #
+ # Evaluates to: this element
+ # doc = Document.new "<a xmlns:foo='bar' xmlns='twiddle'/>"
+ # doc.root.delete_namespace
+ # puts doc # -> <a xmlns:foo='bar'/>
+ # doc.root.delete_namespace 'foo'
+ # puts doc # -> <a/>
+ def delete_namespace namespace="xmlns"
+ namespace = "xmlns:#{namespace}" unless namespace == 'xmlns'
+ attribute = attributes.get_attribute(namespace)
+ attribute.remove unless attribute.nil?
+ self
+ end
+
+ #################################################
+ # Elements #
+ #################################################
+
+ # Adds a child to this element, optionally setting attributes in
+ # the element.
+ # element::
+ # optional. If Element, the element is added.
+ # Otherwise, a new Element is constructed with the argument (see
+ # Element.initialize).
+ # attrs::
+ # If supplied, must be a Hash containing String name,value
+ # pairs, which will be used to set the attributes of the new Element.
+ # Returns:: the Element that was added
+ # el = doc.add_element 'my-tag'
+ # el = doc.add_element 'my-tag', {'attr1'=>'val1', 'attr2'=>'val2'}
+ # el = Element.new 'my-tag'
+ # doc.add_element el
+ def add_element element=nil, attrs=nil
+ el = @elements.add element
+ if attrs.kind_of? Hash
+ attrs.each do |key, value|
+ el.attributes[key]=value if key =~ /^xmlns:/
+ end
+ attrs.each do |key, value|
+ el.attributes[key]=value if key !~ /^xmlns:/
+ end
+ end
+ el
+ end
+
+ # Deletes a child element.
+ # element::
+ # Must be an +Element+, +String+, or +Integer+. If Element,
+ # the element is removed. If String, the element is found (via XPath)
+ # and removed. <em>This means that any parent can remove any
+ # descendant.<em> If Integer, the Element indexed by that number will be
+ # removed.
+ # Returns:: the element that was removed.
+ # doc.delete_element "/a/b/c[@id='4']"
+ # doc.delete_element doc.elements["//k"]
+ # doc.delete_element 1
+ def delete_element element
+ @elements.delete element
+ end
+
+ # Evaluates to +true+ if this element has at least one child Element
+ # doc = Document.new "<a><b/><c>Text</c></a>"
+ # doc.root.has_elements # -> true
+ # doc.elements["/a/b"].has_elements # -> false
+ # doc.elements["/a/c"].has_elements # -> false
+ def has_elements?
+ !@elements.empty?
+ end
+
+ # Iterates through the child elements, yielding for each Element that
+ # has a particular attribute set.
+ # key::
+ # the name of the attribute to search for
+ # value::
+ # the value of the attribute
+ # max::
+ # (optional) causes this method to return after yielding
+ # for this number of matching children
+ # name::
+ # (optional) if supplied, this is an XPath that filters
+ # the children to check.
+ #
+ # doc = Document.new "<a><b @id='1'/><c @id='2'/><d @id='1'/><e/></a>"
+ # # Yields b, c, d
+ # doc.root.each_element_with_attribute( 'id' ) {|e| p e}
+ # # Yields b, d
+ # doc.root.each_element_with_attribute( 'id', '1' ) {|e| p e}
+ # # Yields b
+ # doc.root.each_element_with_attribute( 'id', '1', 1 ) {|e| p e}
+ # # Yields d
+ # doc.root.each_element_with_attribute( 'id', '1', 0, 'd' ) {|e| p e}
+ def each_element_with_attribute( key, value=nil, max=0, name=nil, &block ) # :yields: Element
+ each_with_something( proc {|child|
+ if value.nil?
+ child.attributes[key] != nil
+ else
+ child.attributes[key]==value
+ end
+ }, max, name, &block )
+ end
+
+ # Iterates through the children, yielding for each Element that
+ # has a particular text set.
+ # text::
+ # the text to search for. If nil, or not supplied, will itterate
+ # over all +Element+ children that contain at least one +Text+ node.
+ # max::
+ # (optional) causes this method to return after yielding
+ # for this number of matching children
+ # name::
+ # (optional) if supplied, this is an XPath that filters
+ # the children to check.
+ #
+ # doc = Document.new '<a><b>b</b><c>b</c><d>d</d><e/></a>'
+ # # Yields b, c, d
+ # doc.each_element_with_text {|e|p e}
+ # # Yields b, c
+ # doc.each_element_with_text('b'){|e|p e}
+ # # Yields b
+ # doc.each_element_with_text('b', 1){|e|p e}
+ # # Yields d
+ # doc.each_element_with_text(nil, 0, 'd'){|e|p e}
+ def each_element_with_text( text=nil, max=0, name=nil, &block ) # :yields: Element
+ each_with_something( proc {|child|
+ if text.nil?
+ child.has_text?
+ else
+ child.text == text
+ end
+ }, max, name, &block )
+ end
+
+ # Synonym for Element.elements.each
+ def each_element( xpath=nil, &block ) # :yields: Element
+ @elements.each( xpath, &block )
+ end
+
+ # Synonym for Element.to_a
+ # This is a little slower than calling elements.each directly.
+ # xpath:: any XPath by which to search for elements in the tree
+ # Returns:: an array of Elements that match the supplied path
+ def get_elements( xpath )
+ @elements.to_a( xpath )
+ end
+
+ # Returns the next sibling that is an element, or nil if there is
+ # no Element sibling after this one
+ # doc = Document.new '<a><b/>text<c/></a>'
+ # doc.root.elements['b'].next_element #-> <c/>
+ # doc.root.elements['c'].next_element #-> nil
+ def next_element
+ element = next_sibling
+ element = element.next_sibling until element.nil? or element.kind_of? Element
+ return element
+ end
+
+ # Returns the previous sibling that is an element, or nil if there is
+ # no Element sibling prior to this one
+ # doc = Document.new '<a><b/>text<c/></a>'
+ # doc.root.elements['c'].previous_element #-> <b/>
+ # doc.root.elements['b'].previous_element #-> nil
+ def previous_element
+ element = previous_sibling
+ element = element.previous_sibling until element.nil? or element.kind_of? Element
+ return element
+ end
+
+
+ #################################################
+ # Text #
+ #################################################
+
+ # Evaluates to +true+ if this element has at least one Text child
+ def has_text?
+ not text().nil?
+ end
+
+ # A convenience method which returns the String value of the _first_
+ # child text element, if one exists, and +nil+ otherwise.
+ #
+ # <em>Note that an element may have multiple Text elements, perhaps
+ # separated by other children</em>. Be aware that this method only returns
+ # the first Text node.
+ #
+ # This method returns the +value+ of the first text child node, which
+ # ignores the +raw+ setting, so always returns normalized text. See
+ # the Text::value documentation.
+ #
+ # doc = Document.new "<p>some text <b>this is bold!</b> more text</p>"
+ # # The element 'p' has two text elements, "some text " and " more text".
+ # doc.root.text #-> "some text "
+ def text( path = nil )
+ rv = get_text path
+ return rv.value unless rv.nil?
+ nil
+ end
+
+ # Returns the first child Text node, if any, or +nil+ otherwise.
+ # This method returns the actual +Text+ node, rather than the String content.
+ # doc = Document.new "<p>some text <b>this is bold!</b> more text</p>"
+ # # The element 'p' has two text elements, "some text " and " more text".
+ # doc.root.get_text.value #-> "some text "
+ def get_text path = nil
+ rv = nil
+ if path
+ element = @elements[ path ]
+ rv = element.get_text unless element.nil?
+ else
+ rv = find { |node| node.kind_of? Text }
+ end
+ return rv
+ end
+
+ # Sets the first Text child of this object. See text() for a
+ # discussion about Text children.
+ #
+ # If a Text child already exists, the child is replaced by this
+ # content. This means that Text content can be deleted by calling
+ # this method with a nil argument. In this case, the next Text
+ # child becomes the first Text child. In no case is the order of
+ # any siblings disturbed.
+ # text::
+ # If a String, a new Text child is created and added to
+ # this Element as the first Text child. If Text, the text is set
+ # as the first Child element. If nil, then any existing first Text
+ # child is removed.
+ # Returns:: this Element.
+ # doc = Document.new '<a><b/></a>'
+ # doc.root.text = 'Sean' #-> '<a><b/>Sean</a>'
+ # doc.root.text = 'Elliott' #-> '<a><b/>Elliott</a>'
+ # doc.root.add_element 'c' #-> '<a><b/>Elliott<c/></a>'
+ # doc.root.text = 'Russell' #-> '<a><b/>Russell<c/></a>'
+ # doc.root.text = nil #-> '<a><b/><c/></a>'
+ def text=( text )
+ text = Text.new( text, whitespace(), nil, raw() ) if text.kind_of? String
+ old_text = get_text
+ if text.nil?
+ old_text.remove unless old_text.nil?
+ else
+ if old_text.nil?
+ self << text
+ else
+ old_text.replace_with( text )
+ end
+ end
+ return self
+ end
+
+ # A helper method to add a Text child. Actual Text instances can
+ # be added with regular Parent methods, such as add() and <<()
+ # text::
+ # if a String, a new Text instance is created and added
+ # to the parent. If Text, the object is added directly.
+ # Returns:: this Element
+ # e = Element.new('a') #-> <e/>
+ # e.add_text 'foo' #-> <e>foo</e>
+ # e.add_text Text.new(' bar') #-> <e>foo bar</e>
+ # Note that at the end of this example, the branch has <b>3</b> nodes; the 'e'
+ # element and <b>2</b> Text node children.
+ def add_text( text )
+ if text.kind_of? String
+ if @children[-1].kind_of? Text
+ @children[-1] << text
+ return
+ end
+ text = Text.new( text, whitespace(), nil, raw() )
+ end
+ self << text unless text.nil?
+ return self
+ end
+
+ def node_type
+ :element
+ end
+
+ #################################################
+ # Attributes #
+ #################################################
+
+ def attribute( name, namespace=nil )
+ prefix = ''
+ if namespace
+ prefix = attributes.prefixes.each { |prefix|
+ return "#{prefix}:" if namespace( prefix ) == namespace
+ } || ''
+ end
+ attributes.get_attribute( "#{prefix}#{name}" )
+ end
+
+ # Evaluates to +true+ if this element has any attributes set, false
+ # otherwise.
+ def has_attributes?
+ return !@attributes.empty?
+ end
+
+ # Adds an attribute to this element, overwriting any existing attribute
+ # by the same name.
+ # key::
+ # can be either an Attribute or a String. If an Attribute,
+ # the attribute is added to the list of Element attributes. If String,
+ # the argument is used as the name of the new attribute, and the value
+ # parameter must be supplied.
+ # value::
+ # Required if +key+ is a String, and ignored if the first argument is
+ # an Attribute. This is a String, and is used as the value
+ # of the new Attribute.
+ # Returns:: the Attribute added
+ # e = Element.new 'e'
+ # e.add_attribute( 'a', 'b' ) #-> <e a='b'/>
+ # e.add_attribute( 'x:a', 'c' ) #-> <e a='b' x:a='c'/>
+ # e.add_attribute Attribute.new('b', 'd') #-> <e a='b' x:a='c' b='d'/>
+ def add_attribute( key, value=nil )
+ if key.kind_of? Attribute
+ @attributes << key
+ else
+ @attributes[key] = value
+ end
+ end
+
+ # Add multiple attributes to this element.
+ # hash:: is either a hash, or array of arrays
+ # el.add_attributes( {"name1"=>"value1", "name2"=>"value2"} )
+ # el.add_attributes( [ ["name1","value1"], ["name2"=>"value2"] ] )
+ def add_attributes hash
+ if hash.kind_of? Hash
+ hash.each_pair {|key, value| @attributes[key] = value }
+ elsif hash.kind_of? Array
+ hash.each { |value| @attributes[ value[0] ] = value[1] }
+ end
+ end
+
+ # Removes an attribute
+ # key::
+ # either an Attribute or a String. In either case, the
+ # attribute is found by matching the attribute name to the argument,
+ # and then removed. If no attribute is found, no action is taken.
+ # Returns::
+ # the attribute removed, or nil if this Element did not contain
+ # a matching attribute
+ # e = Element.new('E')
+ # e.add_attribute( 'name', 'Sean' ) #-> <E name='Sean'/>
+ # r = e.add_attribute( 'sur:name', 'Russell' ) #-> <E name='Sean' sur:name='Russell'/>
+ # e.delete_attribute( 'name' ) #-> <E sur:name='Russell'/>
+ # e.delete_attribute( r ) #-> <E/>
+ def delete_attribute(key)
+ attr = @attributes.get_attribute(key)
+ attr.remove unless attr.nil?
+ end
+
+ #################################################
+ # Other Utilities #
+ #################################################
+
+ # Get an array of all CData children.
+ # IMMUTABLE
+ def cdatas
+ find_all { |child| child.kind_of? CData }.freeze
+ end
+
+ # Get an array of all Comment children.
+ # IMMUTABLE
+ def comments
+ find_all { |child| child.kind_of? Comment }.freeze
+ end
+
+ # Get an array of all Instruction children.
+ # IMMUTABLE
+ def instructions
+ find_all { |child| child.kind_of? Instruction }.freeze
+ end
+
+ # Get an array of all Text children.
+ # IMMUTABLE
+ def texts
+ find_all { |child| child.kind_of? Text }.freeze
+ end
+
+ # Writes out this element, and recursively, all children.
+ # output::
+ # output an object which supports '<< string'; this is where the
+ # document will be written.
+ # indent::
+ # An integer. If -1, no indenting will be used; otherwise, the
+ # indentation will be this number of spaces, and children will be
+ # indented an additional amount. Defaults to -1
+ # transitive::
+ # What the heck does this do? Defaults to false
+ # ie_hack::
+ # Internet Explorer is the worst piece of crap to have ever been
+ # written, with the possible exception of Windows itself. Since IE is
+ # unable to parse proper XML, we have to provide a hack to generate XML
+ # that IE's limited abilities can handle. This hack inserts a space
+ # before the /> on empty tags. Defaults to false
+ #
+ # out = ''
+ # doc.write( out ) #-> doc is written to the string 'out'
+ # doc.write( $stdout ) #-> doc written to the console
+ def write(writer=$stdout, indent=-1, transitive=false, ie_hack=false)
+ #print "ID:#{indent}"
+ writer << "<#@expanded_name"
+
+ @attributes.each_attribute do |attr|
+ writer << " "
+ attr.write( writer, indent )
+ end unless @attributes.empty?
+
+ if @children.empty?
+ writer << " " if ie_hack
+ writer << "/"
+ else
+ if transitive and indent>-1 and !@children[0].kind_of? Text
+ writer << "\n"
+ indent writer, indent+2
+ end
+ writer << ">"
+ write_children( writer, indent, transitive, ie_hack )
+ writer << "</#{expanded_name}"
+ end
+ if transitive and indent>-1
+ writer << "\n"
+ indent -= 2 if next_sibling.nil?
+ indent(writer, indent)
+ end
+ writer << ">"
+ end
+
+
+ private
+ # A private helper method
+ def each_with_something( test, max=0, name=nil )
+ num = 0
+ child=nil
+ @elements.each( name ){ |child|
+ yield child if test.call(child) and num += 1
+ return if max>0 and num == max
+ }
+ end
+
+ # A private helper method
+ def write_children( writer, indent, transitive, ie_hack )
+ cr = (indent < 0) ? '' : "\n"
+ #if size == 1 and @children[0].kind_of?(Text)
+ # self[0].write( writer, -1 )
+ if indent == -1
+ each { |child| child.write( writer, indent, transitive, ie_hack ) }
+ else
+ next_indent = indent+2
+ last_child=nil
+ each { |child|
+ unless child.kind_of? Text or last_child.kind_of? Text or transitive
+ writer << cr
+ indent(writer, next_indent)
+ end
+ child.write( writer, next_indent, transitive, ie_hack )
+ last_child = child
+ }
+ unless last_child.kind_of? Text or transitive
+ writer << cr
+ indent( writer, indent )
+ end
+ end
+ end
+ end
+
+ ########################################################################
+ # ELEMENTS #
+ ########################################################################
+
+ # A class which provides filtering of children for Elements, and
+ # XPath search support. You are expected to only encounter this class as
+ # the <tt>element.elements</tt> object. Therefore, you are
+ # _not_ expected to instantiate this yourself.
+ class Elements
+ include Enumerable
+ # Constructor
+ # parent:: the parent Element
+ def initialize parent
+ @element = parent
+ end
+
+ # Fetches a child element. Filters only Element children, regardless of
+ # the XPath match.
+ # index::
+ # the search parameter. This is either an Integer, which
+ # will be used to find the index'th child Element, or an XPath,
+ # which will be used to search for the Element. <em>Because
+ # of the nature of XPath searches, any element in the connected XML
+ # document can be fetched through any other element.</em> <b>The
+ # Integer index is 1-based, not 0-based.</b> This means that the first
+ # child element is at index 1, not 0, and the +n+th element is at index
+ # +n+, not <tt>n-1</tt>. This is because XPath indexes element children
+ # starting from 1, not 0, and the indexes should be the same.
+ # name::
+ # optional, and only used in the first argument is an
+ # Integer. In that case, the index'th child Element that has the
+ # supplied name will be returned. Note again that the indexes start at 1.
+ # Returns:: the first matching Element, or nil if no child matched
+ # doc = Document.new '<a><b/><c id="1"/><c id="2"/><d/></a>'
+ # doc.root.elements[1] #-> <b/>
+ # doc.root.elements['c'] #-> <c id="1"/>
+ # doc.root.elements[2,'c'] #-> <c id="2"/>
+ def []( index, name=nil)
+ if index.kind_of? Integer
+ raise "index (#{index}) must be >= 1" if index < 1
+ name = literalize name if name
+ num = 0
+ child = nil
+ @element.find { |child|
+ child.kind_of? Element and
+ (name.nil? ? true : child.has_name?( name )) and
+ (num += 1) == index
+ }
+ else
+ return XPath::first( @element, index )
+ #{ |element|
+ # return element if element.kind_of? Element
+ #}
+ #return nil
+ end
+ end
+
+ # Sets an element, replacing any previous matching element. If no
+ # existing element is found ,the element is added.
+ # index:: Used to find a matching element to replace. See []().
+ # element::
+ # The element to replace the existing element with
+ # the previous element
+ # Returns:: nil if no previous element was found.
+ #
+ # doc = Document.new '<a/>'
+ # doc.root.elements[10] = Element.new('b') #-> <a><b/></a>
+ # doc.root.elements[1] #-> <b/>
+ # doc.root.elements[1] = Element.new('c') #-> <a><c/></a>
+ # doc.root.elements['c'] = Element.new('d') #-> <a><d/></a>
+ def []=( index, element )
+ previous = self[index]
+ if previous.nil?
+ @element.add element
+ else
+ previous.replace_with element
+ end
+ return previous
+ end
+
+ # Returns +true+ if there are no +Element+ children, +false+ otherwise
+ def empty?
+ @element.find{ |child| child.kind_of? Element}.nil?
+ end
+
+ # Returns the index of the supplied child (starting at 1), or -1 if
+ # the element is not a child
+ # element:: an +Element+ child
+ def index element
+ rv = 0
+ found = @element.find do |child|
+ child.kind_of? Element and
+ (rv += 1) and
+ child == element
+ end
+ return rv if found == element
+ return -1
+ end
+
+ # Deletes a child Element
+ # element::
+ # Either an Element, which is removed directly; an
+ # xpath, where the first matching child is removed; or an Integer,
+ # where the n'th Element is removed.
+ # Returns:: the removed child
+ # doc = Document.new '<a><b/><c/><c id="1"/></a>'
+ # b = doc.root.elements[1]
+ # doc.root.elements.delete b #-> <a><c/><c id="1"/></a>
+ # doc.elements.delete("a/c[@id='1']") #-> <a><c/></a>
+ # doc.root.elements.delete 1 #-> <a/>
+ def delete element
+ if element.kind_of? Element
+ @element.delete element
+ else
+ el = self[element]
+ el.remove if el
+ end
+ end
+
+ # Removes multiple elements. Filters for Element children, regardless of
+ # XPath matching.
+ # xpath:: all elements matching this String path are removed.
+ # Returns:: an Array of Elements that have been removed
+ # doc = Document.new '<a><c/><c/><c/><c/></a>'
+ # deleted = doc.elements.delete_all 'a/c' #-> [<c/>, <c/>, <c/>, <c/>]
+ def delete_all( xpath )
+ rv = []
+ XPath::each( @element, xpath) {|element|
+ rv << element if element.kind_of? Element
+ }
+ rv.each do |element|
+ @element.delete element
+ element.remove
+ end
+ return rv
+ end
+
+ # Adds an element
+ # element::
+ # if supplied, is either an Element, String, or
+ # Source (see Element.initialize). If not supplied or nil, a
+ # new, default Element will be constructed
+ # Returns:: the added Element
+ # a = Element.new 'a'
+ # a.elements.add Element.new 'b' #-> <a><b/></a>
+ # a.elements.add 'c' #-> <a><b/><c/></a>
+ def add element=nil
+ rv = nil
+ if element.nil?
+ Element.new "", self, @element.context
+ elsif not element.kind_of?(Element)
+ Element.new element, self, @element.context
+ else
+ @element << element
+ element.context = @element.context
+ element
+ end
+ end
+
+ alias :<< :add
+
+ # Iterates through all of the child Elements, optionally filtering
+ # them by a given XPath
+ # xpath::
+ # optional. If supplied, this is a String XPath, and is used to
+ # filter the children, so that only matching children are yielded. Note
+ # that XPaths are automatically filtered for Elements, so that
+ # non-Element children will not be yielded
+ # doc = Document.new '<a><b/><c/><d/>sean<b/><c/><d/></a>'
+ # doc.root.each {|e|p e} #-> Yields b, c, d, b, c, d elements
+ # doc.root.each('b') {|e|p e} #-> Yields b, b elements
+ # doc.root.each('child::node()') {|e|p e}
+ # #-> Yields <b/>, <c/>, <d/>, <b/>, <c/>, <d/>
+ # XPath.each(doc.root, 'child::node()', &block)
+ # #-> Yields <b/>, <c/>, <d/>, sean, <b/>, <c/>, <d/>
+ def each( xpath=nil, &block)
+ XPath::each( @element, xpath ) {|e| yield e if e.kind_of? Element }
+ end
+
+ # Returns the number of +Element+ children of the parent object.
+ # doc = Document.new '<a>sean<b/>elliott<b/>russell<b/></a>'
+ # doc.root.size #-> 6, 3 element and 3 text nodes
+ # doc.root.elements.size #-> 3
+ def size
+ count = 0
+ @element.each {|child| count+=1 if child.kind_of? Element }
+ count
+ end
+
+ # Returns an Array of Element children. An XPath may be supplied to
+ # filter the children. Only Element children are returned, even if the
+ # supplied XPath matches non-Element children.
+ # doc = Document.new '<a>sean<b/>elliott<c/></a>'
+ # doc.root.elements.to_a #-> [ <b/>, <c/> ]
+ # doc.root.elements.to_a("child::node()") #-> [ <b/>, <c/> ]
+ # XPath.match(doc.root, "child::node()") #-> [ sean, <b/>, elliott, <c/> ]
+ def to_a( xpath=nil )
+ rv = XPath.match( @element, xpath )
+ return rv.find_all{|e| e.kind_of? Element} if xpath
+ rv
+ end
+
+ private
+ # Private helper class. Removes quotes from quoted strings
+ def literalize name
+ name = name[1..-2] if name[0] == ?' or name[0] == ?" #'
+ name
+ end
+ end
+
+ ########################################################################
+ # ATTRIBUTES #
+ ########################################################################
+
+ # A class that defines the set of Attributes of an Element and provides
+ # operations for accessing elements in that set.
+ class Attributes < Hash
+ # Constructor
+ # element:: the Element of which this is an Attribute
+ def initialize element
+ @element = element
+ end
+
+ # Fetches an attribute value. If you want to get the Attribute itself,
+ # use get_attribute()
+ # name:: an XPath attribute name. Namespaces are relevant here.
+ # Returns::
+ # the String value of the matching attribute, or +nil+ if no
+ # matching attribute was found.
+ #
+ # doc = Document.new "<a foo:att='1' bar:att='2' att='3'/>"
+ # doc.root.attributes['att'] #-> '3'
+ # doc.root.attributes['bar:att'] #-> '2'
+ def [](name)
+ attr = get_attribute(name)
+ return attr.value unless attr.nil?
+ return nil
+ end
+
+ # Returns the number of attributes the owning Element contains.
+ # doc = Document "<a x='1' y='2' foo:x='3'/>"
+ # doc.root.attributes.length #-> 3
+ def length
+ c = 0
+ each_attribute { c+=1 }
+ c
+ end
+ alias :size :length
+
+ # Itterates over the attributes of an Element. Yields actual Attribute
+ # nodes, not String values.
+ #
+ # doc = Document.new '<a x="1" y="2"/>'
+ # doc.root.attributes.each_attribute {|attr|
+ # p attr.expanded_name+" => "+attr.value
+ # }
+ def each_attribute # :yields: attribute
+ each_value do |val|
+ if val.kind_of? Attribute
+ yield val
+ else
+ val.each_value { |atr| yield atr }
+ end
+ end
+ end
+
+ # Itterates over each attribute of an Element, yielding the expanded name
+ # and value as a pair of Strings.
+ #
+ # doc = Document.new '<a x="1" y="2"/>'
+ # doc.root.attributes.each {|name, value| p name+" => "+value }
+ def each
+ each_attribute do |attr|
+ yield attr.expanded_name, attr.value
+ end
+ end
+
+ # Fetches an attribute
+ # name::
+ # the name by which to search for the attribute. Can be a
+ # <tt>prefix:name</tt> namespace name.
+ # Returns:: The first matching attribute, or nil if there was none. This
+ # value is an Attribute node, not the String value of the attribute.
+ # doc = Document.new '<a x:foo="1" foo="2" bar="3"/>'
+ # doc.root.attributes.get_attribute("foo").value #-> "2"
+ # doc.root.attributes.get_attribute("x:foo").value #-> "1"
+ def get_attribute( name )
+ attr = fetch( name, nil )
+ if attr.nil?
+ return nil if name.nil?
+ # Look for prefix
+ name =~ Namespace::NAMESPLIT
+ prefix, n = $1, $2
+ if prefix
+ attr = fetch( n, nil )
+ # check prefix
+ if attr == nil
+ elsif attr.kind_of? Attribute
+ return attr if prefix == attr.prefix
+ else
+ attr = attr[ prefix ]
+ return attr
+ end
+ end
+ if @element.document and @element.document.doctype
+ expn = @element.expanded_name
+ expn = @element.document.doctype.name if expn.size == 0
+ attr_val = @element.document.doctype.attribute_of(expn, name)
+ return Attribute.new( name, attr_val ) if attr_val
+ end
+ return nil
+ end
+ if attr.kind_of? Hash
+ attr = attr[ @element.prefix ]
+ end
+ return attr
+ end
+
+ # Sets an attribute, overwriting any existing attribute value by the
+ # same name. Namespace is significant.
+ # name:: the name of the attribute
+ # value::
+ # (optional) If supplied, the value of the attribute. If
+ # nil, any existing matching attribute is deleted.
+ # Returns::
+ # Owning element
+ # doc = Document.new "<a x:foo='1' foo='3'/>"
+ # doc.root.attributes['y:foo'] = '2'
+ # doc.root.attributes['foo'] = '4'
+ # doc.root.attributes['x:foo'] = nil
+ def []=( name, value )
+ if value.nil? # Delete the named attribute
+ attr = get_attribute name
+ delete attr
+ return
+ end
+ value = Attribute.new(name, value) unless value.kind_of? Attribute
+ value.element = @element
+ old_attr = fetch value.name, nil
+ if old_attr.nil?
+ store(value.name, value)
+ elsif old_attr.kind_of? Hash
+ old_attr[value.prefix] = value
+ elsif old_attr.prefix != value.prefix
+ # Check for conflicting namespaces
+ raise ParseException.new(
+ "Namespace conflict in adding attribute \"#{value.name}\": "+
+ "Prefix \"#{old_attr.prefix}\" = "+
+ "\"#{@element.namespace(old_attr.prefix)}\" and prefix "+
+ "\"#{value.prefix}\" = \"#{@element.namespace(value.prefix)}\"") if
+ value.prefix != "xmlns" and old_attr.prefix != "xmlns" and
+ @element.namespace( old_attr.prefix ) ==
+ @element.namespace( value.prefix )
+ store value.name, { old_attr.prefix => old_attr,
+ value.prefix => value }
+ else
+ store value.name, value
+ end
+ return @element
+ end
+
+ # Returns an array of Strings containing all of the prefixes declared
+ # by this set of # attributes. The array does not include the default
+ # namespace declaration, if one exists.
+ # doc = Document.new("<a xmlns='foo' xmlns:x='bar' xmlns:y='twee' "+
+ # "z='glorp' p:k='gru'/>")
+ # prefixes = doc.root.attributes.prefixes #-> ['x', 'y']
+ def prefixes
+ ns = []
+ each_attribute do |attribute|
+ ns << attribute.name if attribute.prefix == 'xmlns'
+ end
+ if @element.document and @element.document.doctype
+ expn = @element.expanded_name
+ expn = @element.document.doctype.name if expn.size == 0
+ @element.document.doctype.attributes_of(expn).each {
+ |attribute|
+ ns << attribute.name if attribute.prefix == 'xmlns'
+ }
+ end
+ ns
+ end
+
+ def namespaces
+ namespaces = []
+ each_attribute do |attribute|
+ namespaces << attribute.value if attribute.prefix == 'xmlns' or attribute.name == 'xmlns'
+ end
+ if @element.document and @element.document.doctype
+ expn = @element.expanded_name
+ expn = @element.document.doctype.name if expn.size == 0
+ @element.document.doctype.attributes_of(expn).each {
+ |attribute|
+ namespaces << attribute.value if attribute.prefix == 'xmlns' or attribute.name == 'xmlns'
+ }
+ end
+ namespaces
+ end
+
+ # Removes an attribute
+ # attribute::
+ # either a String, which is the name of the attribute to remove --
+ # namespaces are significant here -- or the attribute to remove.
+ # Returns:: the owning element
+ # doc = Document.new "<a y:foo='0' x:foo='1' foo='3' z:foo='4'/>"
+ # doc.root.attributes.delete 'foo' #-> <a y:foo='0' x:foo='1' z:foo='4'/>"
+ # doc.root.attributes.delete 'x:foo' #-> <a y:foo='0' z:foo='4'/>"
+ # attr = doc.root.attributes.get_attribute('y:foo')
+ # doc.root.attributes.delete attr #-> <a z:foo='4'/>"
+ def delete( attribute )
+ name = nil
+ prefix = nil
+ if attribute.kind_of? Attribute
+ name = attribute.name
+ prefix = attribute.prefix
+ else
+ attribute =~ Namespace::NAMESPLIT
+ prefix, name = $1, $2
+ prefix = '' unless prefix
+ end
+ old = fetch name, nil
+ attr = nil
+ if old.kind_of? Hash # the supplied attribute is one of many
+ attr = old.delete(prefix)
+ if old.size == 1
+ repl = nil
+ old.each_value{|v| repl = v}
+ store name, repl
+ end
+ elsif old.nil?
+ return @element
+ else # the supplied attribute is a top-level one
+ attr = old
+ res = super(name)
+ end
+ @element
+ end
+
+ # Adds an attribute, overriding any existing attribute by the
+ # same name. Namespaces are significant.
+ # attribute:: An Attribute
+ def add( attribute )
+ self[attribute.name] = attribute
+ end
+
+ alias :<< :add
+
+ # Deletes all attributes matching a name. Namespaces are significant.
+ # name::
+ # A String; all attributes that match this path will be removed
+ # Returns:: an Array of the Attributes that were removed
+ def delete_all( name )
+ rv = []
+ each_attribute { |attribute|
+ rv << attribute if attribute.expanded_name == name
+ }
+ rv.each{ |attr| attr.remove }
+ return rv
+ end
+ end
+end