# -*- encoding: utf-8; frozen_string_literal: true -*-
#
#--
# This file is part of HexaPDF.
#
# HexaPDF - A Versatile PDF Creation and Manipulation Library For Ruby
# Copyright (C) 2014-2021 Thomas Leitner
#
# HexaPDF is free software: you can redistribute it and/or modify it
# under the terms of the GNU Affero General Public License version 3 as
# published by the Free Software Foundation with the addition of the
# following permission added to Section 15 as permitted in Section 7(a):
# FOR ANY PART OF THE COVERED WORK IN WHICH THE COPYRIGHT IS OWNED BY
# THOMAS LEITNER, THOMAS LEITNER DISCLAIMS THE WARRANTY OF NON
# INFRINGEMENT OF THIRD PARTY RIGHTS.
#
# HexaPDF is distributed in the hope that it will be useful, but WITHOUT
# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
# FITNESS FOR A PARTICULAR PURPOSE. See the GNU Affero General Public
# License for more details.
#
# You should have received a copy of the GNU Affero General Public License
# along with HexaPDF. If not, see .
#
# The interactive user interfaces in modified source and object code
# versions of HexaPDF must display Appropriate Legal Notices, as required
# under Section 5 of the GNU Affero General Public License version 3.
#
# In accordance with Section 7(b) of the GNU Affero General Public
# License, a covered work must retain the producer line in every PDF that
# is created or manipulated using HexaPDF.
#
# If the GNU Affero General Public License doesn't fit your need,
# commercial licenses are available at .
#++
require 'stringio'
require 'hexapdf/error'
require 'hexapdf/data_dir'
require 'hexapdf/content'
require 'hexapdf/configuration'
require 'hexapdf/reference'
require 'hexapdf/object'
require 'hexapdf/pdf_array'
require 'hexapdf/stream'
require 'hexapdf/revisions'
require 'hexapdf/type'
require 'hexapdf/task'
require 'hexapdf/encryption'
require 'hexapdf/writer'
require 'hexapdf/importer'
require 'hexapdf/image_loader'
require 'hexapdf/font_loader'
require 'hexapdf/layout'
begin
require 'hexapdf/cext'
rescue LoadError
# ignore error because the C-extension only makes things faster
end
# == HexaPDF API Documentation
#
# Here are some pointers to more in depth information:
#
# * For information about the command line application, see the HexaPDF::CLI module.
# * HexaPDF::Document provides information about how to work with a PDF file.
# * HexaPDF::Content::Canvas provides the canvas API for drawing/writing on a page or form XObject
module HexaPDF
autoload(:Composer, 'hexapdf/composer')
# == HexaPDF::Document
#
# Represents one PDF document.
#
# A PDF document consists of (indirect) objects, so the main job of this class is to provide
# methods for working with these objects. However, since a PDF document may also be
# incrementally updated and can therefore contain one or more revisions, there are also methods
# for working with these revisions.
#
# Note: This class provides everything to work on PDF documents on a low-level basis. This means
# that there are no convenience methods for higher PDF functionality. Those can be found in the
# objects linked from here, like #catalog.
#
# == Known Messages
#
# The document object provides a basic message dispatch system via #register_listener and
# #dispatch_message.
#
# Following are the messages that are used by HexaPDF itself:
#
# :complete_objects::
# This message is called before the first step of writing a document. Listeners should
# complete PDF objects that are missing some information.
#
# For example, the font system uses this message to complete the font objects with
# information that is only available once all the used glyphs are known.
#
# :before_write::
# This message is called before a document is actually serialized and written.
class Document
autoload(:Pages, 'hexapdf/document/pages')
autoload(:Fonts, 'hexapdf/document/fonts')
autoload(:Images, 'hexapdf/document/images')
autoload(:Files, 'hexapdf/document/files')
autoload(:Signatures, 'hexapdf/document/signatures')
# :call-seq:
# Document.open(filename, **docargs) -> doc
# Document.open(filename, **docargs) {|doc| block} -> obj
#
# Creates a new PDF Document object for the given file.
#
# Depending on whether a block is provided, the functionality is different:
#
# * If no block is provided, the whole file is instantly read into memory and the PDF Document
# created for it is returned.
#
# * If a block is provided, the file is opened and a PDF Document is created for it. The
# created document is passed as an argument to the block and when the block returns the
# associated file object is closed. The value of the block will be returned.
#
# The block version is useful, for example, when you are dealing with a large file and you
# only need a small portion of it.
#
# The provided keyword arguments (except +io+) are passed on unchanged to Document.new.
def self.open(filename, **kwargs)
if block_given?
File.open(filename, 'rb') do |file|
yield(new(**kwargs, io: file))
end
else
new(**kwargs, io: StringIO.new(File.binread(filename)))
end
end
# The configuration for the document.
attr_reader :config
# The revisions of the document.
attr_reader :revisions
# Creates a new PDF document, either an empty one or one read from the provided +io+.
#
# When an IO object is provided and it contains an encrypted PDF file, it is automatically
# decrypted behind the scenes. The +decryption_opts+ argument has to be set appropriately in
# this case.
#
# Options:
#
# io:: If an IO object is provided, then this document can read PDF objects from this IO
# object, otherwise it can only contain created PDF objects.
#
# decryption_opts:: A hash with options for decrypting the PDF objects loaded from the IO.
#
# config:: A hash with configuration options that is deep-merged into the default configuration
# (see
# HexaPDF::DefaultDocumentConfiguration[../index.html#DefaultDocumentConfiguration],
# meaning that direct sub-hashes are merged instead of overwritten.
def initialize(io: nil, decryption_opts: {}, config: {})
@config = Configuration.with_defaults(config)
@version = '1.2'
@revisions = Revisions.from_io(self, io)
@security_handler = if encrypted? && @config['document.auto_decrypt']
Encryption::SecurityHandler.set_up_decryption(self, **decryption_opts)
else
nil
end
@listeners = {}
@cache = Hash.new {|h, k| h[k] = {} }
end
# :call-seq:
# doc.object(ref) -> obj or nil
# doc.object(oid) -> obj or nil
#
# Returns the current version of the indirect object for the given exact reference or for the
# given object number.
#
# For references to unknown objects, +nil+ is returned but free objects are represented by a
# PDF Null object, not by +nil+!
#
# See: PDF1.7 s7.3.9
def object(ref)
i = @revisions.size - 1
while i >= 0
return @revisions[i].object(ref) if @revisions[i].object?(ref)
i -= 1
end
nil
end
# Dereferences the given object.
#
# Return the object itself if it is not a reference, or the indirect object specified by the
# reference.
def deref(obj)
obj.kind_of?(Reference) ? object(obj) : obj
end
# :call-seq:
# doc.object?(ref) -> true or false
# doc.object?(oid) -> true or false
#
# Returns +true+ if the the document contains an indirect object for the given exact reference
# or for the given object number.
#
# Even though this method might return +true+ for some references, #object may return +nil+
# because this method takes *all* revisions into account. Also see the discussion on #each for
# more information.
def object?(ref)
@revisions.any? {|rev| rev.object?(ref) }
end
# :call-seq:
# doc.add(obj, revision: :current, **wrap_opts) -> indirect_object
#
# Adds the object to the specified revision of the document and returns the wrapped indirect
# object.
#
# The object can either be a native Ruby object (Hash, Array, Integer, ...) or a
# HexaPDF::Object. If it is not the latter, #wrap is called with the object and the
# additional keyword arguments.
#
# If the +revision+ option is +:current+, the current revision is used. Otherwise +revision+
# should be a revision index.
def add(obj, revision: :current, **wrap_opts)
obj = wrap(obj, **wrap_opts) unless obj.kind_of?(HexaPDF::Object)
revision = (revision == :current ? @revisions.current : @revisions.revision(revision))
if revision.nil?
raise ArgumentError, "Invalid revision index specified"
end
if obj.document? && obj.document != self
raise HexaPDF::Error, "Can't add object that is already attached to another document"
end
obj.document = self
if obj.indirect? && (rev_obj = revision.object(obj.oid))
if rev_obj.equal?(obj)
return obj
else
raise HexaPDF::Error, "Can't add object because the specified revision already has " \
"an object with object number #{obj.oid}"
end
end
obj.oid = @revisions.map(&:next_free_oid).max unless obj.indirect?
revision.add(obj)
end
# :call-seq:
# doc.delete(ref, revision: :all)
# doc.delete(oid, revision: :all)
#
# Deletes the indirect object specified by an exact reference or by an object number from the
# document.
#
# Options:
#
# revision:: Specifies from which revisions the object should be deleted:
#
# :all:: Delete the object from all revisions.
# :current:: Delete the object only from the current revision.
#
# mark_as_free:: If +true+, objects are only marked as free objects instead of being actually
# deleted.
def delete(ref, revision: :all, mark_as_free: true)
case revision
when :current
@revisions.current.delete(ref, mark_as_free: mark_as_free)
when :all
@revisions.each {|rev| rev.delete(ref, mark_as_free: mark_as_free) }
else
raise ArgumentError, "Unsupported option revision: #{revision}"
end
end
# :call-seq:
# doc.import(obj) -> imported_object
#
# Imports the given, with a different document associated PDF object and returns the imported
# object.
#
# If the same argument is provided in multiple invocations, the import is done only once and
# the previously imoprted object is returned.
#
# See: Importer
def import(obj)
if !obj.kind_of?(HexaPDF::Object) || !obj.document? || obj.document == self
raise ArgumentError, "Importing only works for PDF objects associated " \
"with another document"
end
HexaPDF::Importer.for(source: obj.document, destination: self).import(obj)
end
# Wraps the given object inside a HexaPDF::Object class which allows one to use
# convenience functions to work with the object.
#
# The +obj+ argument can also be a HexaPDF::Object object so that it can be re-wrapped if
# needed.
#
# The class of the returned object is always a subclass of HexaPDF::Object (or of
# HexaPDF::Stream if a +stream+ is given). Which subclass is used, depends on the values of the
# +type+ and +subtype+ options as well as on the 'object.type_map' and 'object.subtype_map'
# global configuration options:
#
# * First +type+ is used to try to determine the class. If it is not provided and if +obj+ is a
# hash with a :Type field, the value of this field is used instead. If the resulting object is
# already a Class object, it is used, otherwise the type is looked up in 'object.type_map'.
#
# * If +subtype+ is provided or can be determined because +obj+ is a hash with a :Subtype or :S
# field, the type and subtype together are used to look up a special subtype class in
# 'object.subtype_map'.
#
# Additionally, if there is no +type+ but a +subtype+, all required fields of the subtype
# class need to have values; otherwise the subtype class is not used. This is done to better
# prevent invalid mappings when only partial knowledge (:Type key is missing) is available.
#
# * If there is no valid class after the above steps, HexaPDF::Stream is used if a stream is
# given, HexaPDF::Dictionary if the given object is a hash, HexaPDF::PDFArray if it is an
# array or else HexaPDF::Object is used.
#
# Options:
#
# :type:: (Symbol or Class) The type of a PDF object that should be used for wrapping. This
# could be, for example, :Pages. If a class object is provided, it is used directly
# instead of the type detection system.
#
# :subtype:: (Symbol) The subtype of a PDF object which further qualifies a type. For
# example, image objects in PDF have a type of :XObject and a subtype of :Image.
#
# :oid:: (Integer) The object number that should be set on the wrapped object. Defaults to 0
# or the value of the given object's object number.
#
# :gen:: (Integer) The generation number that should be set on the wrapped object. Defaults to
# 0 or the value of the given object's generation number.
#
# :stream:: (String or StreamData) The stream object which should be set on the wrapped
# object.
def wrap(obj, type: nil, subtype: nil, oid: nil, gen: nil, stream: nil)
data = if obj.kind_of?(HexaPDF::Object)
obj.data
else
HexaPDF::PDFData.new(obj)
end
data.oid = oid if oid
data.gen = gen if gen
data.stream = stream if stream
if type.kind_of?(Class)
klass = type
type = (klass <= HexaPDF::Dictionary ? klass.type : nil)
else
type ||= deref(data.value[:Type]) if data.value.kind_of?(Hash)
klass = GlobalConfiguration.constantize('object.type_map', type) { nil } if type
end
if data.value.kind_of?(Hash)
subtype ||= deref(data.value[:Subtype]) || deref(data.value[:S])
end
if subtype
sub_klass = GlobalConfiguration.constantize('object.subtype_map', type, subtype) { klass }
if type ||
sub_klass&.each_field&.none? {|name, field| field.required? && !data.value.key?(name) }
klass = sub_klass
end
end
klass ||= if data.stream
HexaPDF::Stream
elsif data.value.kind_of?(Hash)
HexaPDF::Dictionary
elsif data.value.kind_of?(Array)
HexaPDF::PDFArray
else
HexaPDF::Object
end
klass.new(data, document: self)
end
# :call-seq:
# document.unwrap(obj) -> unwrapped_obj
#
# Recursively unwraps the object to get native Ruby objects (i.e. Hash, Array, Integer, ...
# instead of HexaPDF::Reference and HexaPDF::Object).
def unwrap(object, seen = {})
object = deref(object)
object = object.data if object.kind_of?(HexaPDF::Object)
if seen.key?(object)
raise HexaPDF::Error, "Can't unwrap a recursive structure"
end
case object
when Hash
seen[object] = true
object.transform_values {|value| unwrap(value, seen.dup) }
when Array
seen[object] = true
object.map {|inner_o| unwrap(inner_o, seen.dup) }
when HexaPDF::PDFData
seen[object] = true
unwrap(object.value, seen.dup)
else
object
end
end
# :call-seq:
# doc.each(only_current: true, only_loaded: false) {|obj| block } -> doc
# doc.each(only_current: true, only_loaded: false) {|obj, rev| block } -> doc
# doc.each(only_current: true, only_loaded: false) -> Enumerator
#
# Calls the given block once for every object, or, if +only_loaded+ is +true+, for every loaded
# object in the PDF document. The block may either accept only the object or the object and the
# revision it is in.
#
# By default, only the current version of each object is returned which implies that each object
# number is yielded exactly once. If the +only_current+ option is +false+, all stored objects
# from newest to oldest are returned, not only the current version of each object.
#
# The +only_current+ option can make a difference because the document can contain multiple
# revisions:
#
# * Multiple revisions may contain objects with the same object and generation numbers, e.g.
# two (different) objects with oid/gen [3,0].
#
# * Additionally, there may also be objects with the same object number but different
# generation numbers in different revisions, e.g. one object with oid/gen [3,0] and one with
# oid/gen [3,1].
def each(only_current: true, only_loaded: false, &block)
unless block_given?
return to_enum(__method__, only_current: only_current, only_loaded: only_loaded)
end
yield_rev = (block.arity == 2)
oids = {}
@revisions.reverse_each do |rev|
rev.each(only_loaded: only_loaded) do |obj|
next if only_current && oids.include?(obj.oid)
(yield_rev ? yield(obj, rev) : yield(obj))
oids[obj.oid] = true
end
end
self
end
# :call-seq:
# doc.register_listener(name, callable) -> callable
# doc.register_listener(name) {|*args| block} -> block
#
# Registers the given listener for the message +name+.
def register_listener(name, callable = nil, &block)
callable ||= block
(@listeners[name] ||= []) << callable
callable
end
# Dispatches the message +name+ with the given arguments to all registered listeners.
#
# See the main Document documentation for an overview of messages that are used by HexaPDF
# itself.
def dispatch_message(name, *args)
@listeners[name]&.each {|obj| obj.call(*args) }
end
UNSET = ::Object.new # :nordoc:
# Caches and returns the given +value+ or the value of the given block using the given
# +pdf_data+ and +key+ arguments as composite cache key. If a cached value already exists and
# +update+ is +false+, the cached value is just returned.
#
# Set +update+ to +true+ to force an update of the cached value.
#
# This facility can be used to cache expensive operations in PDF objects that are easy to
# compute again.
#
# Use #clear_cache to clear the cache if necessary.
def cache(pdf_data, key, value = UNSET, update: false)
return @cache[pdf_data][key] if cached?(pdf_data, key) && !update
@cache[pdf_data][key] = (value == UNSET ? yield : value)
end
# Returns +true+ if there is a value cached for the composite key consisting of the given
# +pdf_data+ and +key+ objects.
#
# Also see: #cache
def cached?(pdf_data, key)
@cache.key?(pdf_data) && @cache[pdf_data].key?(key)
end
# Clears all cached data or, if a Object::PDFData object is given, just the cache for this one
# object.
#
# It is *not* recommended to clear the whole cache! Better clear the cache for individual PDF
# objects!
#
# Also see: #cache
def clear_cache(pdf_data = nil)
pdf_data ? @cache[pdf_data].clear : @cache.clear
end
# Returns the Pages object that provides convenience methods for working with pages.
#
# Also see: HexaPDF::Type::PageTreeNode
def pages
@pages ||= Pages.new(self)
end
# Returns the Images object that provides convenience methods for working with images.
def images
@images ||= Images.new(self)
end
# Returns the Files object that provides convenience methods for working with files.
def files
@files ||= Files.new(self)
end
# Returns the Fonts object that provides convenience methods for working with fonts.
def fonts
@fonts ||= Fonts.new(self)
end
# Returns the main AcroForm object for dealing with interactive forms.
#
# See HexaPDF::Type::Catalog#acro_form for details on the arguments.
def acro_form(create: false)
catalog.acro_form(create: create)
end
# Executes the given task and returns its result.
#
# Tasks provide an extensible way for performing operations on a PDF document without
# cluttering the Document interface.
#
# See Task for more information.
def task(name, **opts, &block)
task = config.constantize('task.map', name) do
raise HexaPDF::Error, "No task named '#{name}' is available"
end
task.call(self, **opts, &block)
end
# Returns the trailer dictionary for the document.
def trailer
@revisions.current.trailer
end
# Returns the document's catalog, the root of the object tree.
def catalog
trailer.catalog
end
# Returns the PDF document's version as string (e.g. '1.4').
#
# This method takes the file header version and the catalog's /Version key into account. If a
# version has been set manually and the catalog's /Version key refers to a later version, the
# later version is used.
#
# See: PDF1.7 s7.2.2
def version
catalog_version = (catalog[:Version] || '1.0').to_s
(@version < catalog_version ? catalog_version : @version)
end
# Sets the version of the PDF document. The argument must be a string in the format 'M.N'
# where M is the major version and N the minor version (e.g. '1.4' or '2.0').
def version=(value)
raise ArgumentError, "PDF version must follow format M.N" unless value.to_s.match?(/\A\d\.\d\z/)
@version = value.to_s
end
# Returns +true+ if the document is encrypted.
def encrypted?
!trailer[:Encrypt].nil?
end
# Encrypts the document.
#
# This is done by setting up a security handler for this purpose and populating the trailer's
# Encrypt dictionary accordingly. The actual encryption, however, is only done when writing the
# document.
#
# The security handler used for encrypting is selected via the +name+ argument. All other
# arguments are passed on the security handler.
#
# If the document should not be encrypted, the +name+ argument has to be set to +nil+. This
# removes the security handler and deletes the trailer's Encrypt dictionary.
#
# See: HexaPDF::Encryption::SecurityHandler#set_up_encryption and
# HexaPDF::Encryption::StandardSecurityHandler::EncryptionOptions for possible encryption
# options.
def encrypt(name: :Standard, **options)
if name.nil?
trailer.delete(:Encrypt)
@security_handler = nil
else
@security_handler = Encryption::SecurityHandler.set_up_encryption(self, name, **options)
end
end
# Returns the security handler that is used for decrypting or encrypting the document, or +nil+
# if none is set.
#
# * If the document was created by reading an existing file and the document was automatically
# decrypted, then this method returns the handler for decrypting.
#
# * Once the #encrypt method is called, the specified security handler for encrypting is
# returned.
def security_handler
@security_handler
end
# Returns +true+ if the document is signed, i.e. contains digital signatures.
def signed?
acro_form&.signature_flag?(:signatures_exist)
end
# Returns an array with the digital signatures of this document.
def signatures
@signatures ||= Signatures.new(self)
end
# Signs the document and writes it to the given file or IO object.
#
# For details on the arguments +file_or_io+, +signature+ and +write_options+ see
# HexaPDF::Document::Signatures#add.
#
# The signing handler to be used is determined by the +handler+ argument together with the rest
# of the keyword arguments (see HexaPDF::Document::Signatures#handler for details).
#
# If not changed, the default signing handler is HexaPDF::Document::Signatures::DefaultHandler.
def sign(file_or_io, handler: :default, signature: nil, write_options: {}, **handler_options)
handler = signatures.handler(name: handler, **handler_options)
signatures.add(file_or_io, handler, signature: signature, write_options: write_options)
end
# Validates all objects, or, if +only_loaded+ is +true+, only loaded objects, with optional
# auto-correction, and returns +true+ if everything is fine.
#
# If a block is given, it is called on validation problems.
#
# See HexaPDF::Object#validate for more information.
def validate(auto_correct: true, only_loaded: false, &block) #:yield: msg, correctable, object
result = trailer.validate(auto_correct: auto_correct, &block)
each(only_current: false, only_loaded: only_loaded) do |obj|
result &&= obj.validate(auto_correct: auto_correct, &block)
end
result
end
# :call-seq:
# doc.write(filename, incremental: false, validate: true, update_fields: true, optimize: false)
# doc.write(io, incremental: false, validate: true, update_fields: true, optimize: false)
#
# Writes the document to the given file (in case +io+ is a String) or IO stream.
#
# Before the document is written, it is validated using #validate and an error is raised if the
# document is not valid. However, this step can be skipped if needed.
#
# Options:
#
# incremental::
# Use the incremental writing mode which just adds a new revision to an existing document.
# This is needed, for example, when modifying a signed PDF and the original signature should
# stay valid.
#
# See: PDF1.7 s7.5.6
#
# validate::
# Validates the document and raises an error if an uncorrectable problem is found.
#
# update_fields::
# Updates the /ID field in the trailer dictionary as well as the /ModDate field in the
# trailer's /Info dictionary so that it is clear that the document has been updated.
#
# optimize::
# Optimize the file size by using object and cross-reference streams. This will raise the PDF
# version to at least 1.5.
def write(file_or_io, incremental: false, validate: true, update_fields: true, optimize: false)
dispatch_message(:complete_objects)
if update_fields
trailer.update_id
trailer.info[:ModDate] = Time.now
end
if validate
self.validate(auto_correct: true) do |msg, correctable, obj|
next if correctable
raise HexaPDF::Error, "Validation error for (#{obj.oid},#{obj.gen}): #{msg}"
end
end
if optimize
task(:optimize, object_streams: :generate)
self.version = '1.5' if version < '1.5'
end
dispatch_message(:before_write)
if file_or_io.kind_of?(String)
File.open(file_or_io, 'w+') {|file| Writer.write(self, file, incremental: incremental) }
else
Writer.write(self, file_or_io, incremental: incremental)
end
end
end
end