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require 'rexml/child'
require 'rexml/source'
require 'rexml/xmltokens'
module REXML
# God, I hate DTDs. I really do. Why this idiot standard still
# plagues us is beyond me.
class Entity < Child
include XMLTokens
PUBIDCHAR = "\x20\x0D\x0Aa-zA-Z0-9\\-()+,./:=?;!*@$_%#"
SYSTEMLITERAL = %Q{((?:"[^"]*")|(?:'[^']*'))}
PUBIDLITERAL = %Q{("[#{PUBIDCHAR}']*"|'[#{PUBIDCHAR}]*')}
EXTERNALID = "(?:(?:(SYSTEM)\\s+#{SYSTEMLITERAL})|(?:(PUBLIC)\\s+#{PUBIDLITERAL}\\s+#{SYSTEMLITERAL}))"
NDATADECL = "\\s+NDATA\\s+#{NAME}"
PEREFERENCE = "%#{NAME};"
ENTITYVALUE = %Q{((?:"(?:[^%&"]|#{PEREFERENCE}|#{REFERENCE})*")|(?:'([^%&']|#{PEREFERENCE}|#{REFERENCE})*'))}
PEDEF = "(?:#{ENTITYVALUE}|#{EXTERNALID})"
ENTITYDEF = "(?:#{ENTITYVALUE}|(?:#{EXTERNALID}(#{NDATADECL})?))"
PEDECL = "<!ENTITY\\s+(%)\\s+#{NAME}\\s+#{PEDEF}\\s*>"
GEDECL = "<!ENTITY\\s+#{NAME}\\s+#{ENTITYDEF}\\s*>"
ENTITYDECL = /\s*(?:#{GEDECL})|(?:#{PEDECL})/um
attr_reader :name, :external, :ref, :ndata, :pubid
# Create a new entity. Simple entities can be constructed by passing a
# name, value to the constructor; this creates a generic, plain entity
# reference. For anything more complicated, you have to pass a Source to
# the constructor with the entity definition, or use the accessor methods.
# +WARNING+: There is no validation of entity state except when the entity
# is read from a stream. If you start poking around with the accessors,
# you can easily create a non-conformant Entity. The best thing to do is
# dump the stupid DTDs and use XMLSchema instead.
#
# e = Entity.new( 'amp', '&' )
def initialize stream, value=nil, parent=nil, reference=false
super(parent)
@ndata = @pubid = @value = @external = nil
if stream.kind_of? Array
@name = stream[1]
if stream[-1] == '%'
@reference = true
stream.pop
else
@reference = false
end
if stream[2] =~ /SYSTEM|PUBLIC/
@external = stream[2]
if @external == 'SYSTEM'
@ref = stream[3]
@ndata = stream[4] if stream.size == 5
else
@pubid = stream[3]
@ref = stream[4]
end
else
@value = stream[2]
end
else
@reference = reference
@external = nil
@name = stream
@value = value
end
end
# Evaluates whether the given string matches an entity definition,
# returning true if so, and false otherwise.
def Entity::matches? string
(ENTITYDECL =~ string) == 0
end
# Evaluates to the unnormalized value of this entity; that is, replacing
# all entities -- both %ent; and &ent; entities. This differs from
# +value()+ in that +value+ only replaces %ent; entities.
def unnormalized
document.record_entity_expansion unless document.nil?
v = value()
return nil if v.nil?
@unnormalized = Text::unnormalize(v, parent)
@unnormalized
end
#once :unnormalized
# Returns the value of this entity unprocessed -- raw. This is the
# normalized value; that is, with all %ent; and &ent; entities intact
def normalized
@value
end
# Write out a fully formed, correct entity definition (assuming the Entity
# object itself is valid.)
#
# out::
# An object implementing <TT><<<TT> to which the entity will be
# output
# indent::
# *DEPRECATED* and ignored
def write out, indent=-1
out << '<!ENTITY '
out << '% ' if @reference
out << @name
out << ' '
if @external
out << @external << ' '
if @pubid
q = @pubid.include?('"')?"'":'"'
out << q << @pubid << q << ' '
end
q = @ref.include?('"')?"'":'"'
out << q << @ref << q
out << ' NDATA ' << @ndata if @ndata
else
q = @value.include?('"')?"'":'"'
out << q << @value << q
end
out << '>'
end
# Returns this entity as a string. See write().
def to_s
rv = ''
write rv
rv
end
PEREFERENCE_RE = /#{PEREFERENCE}/um
# Returns the value of this entity. At the moment, only internal entities
# are processed. If the value contains internal references (IE,
# %blah;), those are replaced with their values. IE, if the doctype
# contains:
# <!ENTITY % foo "bar">
# <!ENTITY yada "nanoo %foo; nanoo>
# then:
# doctype.entity('yada').value #-> "nanoo bar nanoo"
def value
if @value
matches = @value.scan(PEREFERENCE_RE)
rv = @value.clone
if @parent
sum = 0
matches.each do |entity_reference|
entity_value = @parent.entity( entity_reference[0] )
if sum + entity_value.bytesize > Security.entity_expansion_text_limit
raise "entity expansion has grown too large"
else
sum += entity_value.bytesize
end
rv.gsub!( /%#{entity_reference.join};/um, entity_value )
end
end
return rv
end
nil
end
end
# This is a set of entity constants -- the ones defined in the XML
# specification. These are +gt+, +lt+, +amp+, +quot+ and +apos+.
# CAUTION: these entities does not have parent and document
module EntityConst
# +>+
GT = Entity.new( 'gt', '>' )
# +<+
LT = Entity.new( 'lt', '<' )
# +&+
AMP = Entity.new( 'amp', '&' )
# +"+
QUOT = Entity.new( 'quot', '"' )
# +'+
APOS = Entity.new( 'apos', "'" )
end
end
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