Also read/update headers and footers

Inspired by PR ruby-docx#73
we adapted the code to work on top of the current
state.

lib/docx/document.rb

@@ -20,6 +20,14 @@ module Docx
   class Document
     attr_reader :xml, :doc, :zip, :styles
 
+    DOCUMENT_PATHS = {
+      styles:    "word/styles.xml",
+      rels:      "word/_rels/document.xml.rels",
+      headers:   "word/header*.xml",
+      footers:   "word/footer*.xml",
+      numbering: "word/numbering.xml"
+    }
+
     def initialize(path_or_io, options = {})
       @replace = {}
 
@@ -35,7 +43,12 @@ def initialize(path_or_io, options = {})
 
       @document_xml = document.get_input_stream.read
       @doc = Nokogiri::XML(@document_xml)
+
       load_styles
+      load_headers
+      load_footers
+      load_numbering
+
       yield(self) if block_given?
     ensure
       @zip.close
@@ -64,9 +77,12 @@ def paragraphs
     def bookmarks
       bkmrks_hsh = {}
       bkmrks_ary = @doc.xpath('//w:bookmarkStart').map { |b_node| parse_bookmark_from b_node }
+      bkmrks_ary += @headers.values.map { |xml_doc| xml_doc.xpath('//w:bookmarkStart').map { |b_node| parse_bookmark_from b_node } }.flatten
+      bkmrks_ary += @footers.values.map { |xml_doc| xml_doc.xpath('//w:bookmarkStart').map { |b_node| parse_bookmark_from b_node } }.flatten
       # auto-generated by office 2010
       bkmrks_ary.reject! { |b| b.name == '_GoBack' }
       bkmrks_ary.each { |b| bkmrks_hsh[b.name] = b }
+
       bkmrks_hsh
     end
 
@@ -166,24 +182,68 @@ def replace_entry(entry_path, file_contents)
     private
 
     def load_styles
-      @styles_xml = @zip.read('word/styles.xml')
-      @styles = Nokogiri::XML(@styles_xml)
-      @rels_xml = @zip.read('word/_rels/document.xml.rels')
-      @rels = Nokogiri::XML(@rels_xml)
-    rescue Errno::ENOENT => e
-      warn e.message
-      nil
+      extract_single_document_from_path :styles
+      extract_single_document_from_path :rels
+    end
+
+    def load_headers
+      extract_multiple_documents_from_globbed_path :headers
+    end
+
+    def load_footers
+      extract_multiple_documents_from_globbed_path :footers
+    end
+
+    def load_numbering
+      extract_single_document_from_path :numbering
+    end
+
+    def extract_single_document_from_path(attr_name)
+      path = DOCUMENT_PATHS[attr_name]
+      if @zip.find_entry(path)
+        xml_doc = @zip.read(path)
+        self.instance_variable_set(:"@#{attr_name}", Nokogiri::XML(xml_doc))
+      end
+    end
+
+    def extract_multiple_documents_from_globbed_path(attr_name)
+      glob_path = DOCUMENT_PATHS[attr_name]
+      files = @zip.glob(glob_path).map { |h| h.name }
+      filename_and_contents_pairs = files.map do |file|
+        simple_file_name = file.sub(/^word\//, "").sub(/\.xml$/, "")
+        [simple_file_name, Nokogiri::XML(@zip.read(file))]
+      end
+      hash = Hash[filename_and_contents_pairs]
+      self.instance_variable_set(:"@#{attr_name}", hash)
     end
 
     #--
     # TODO: Flesh this out to be compatible with other files
     # TODO: Method to set flag on files that have been edited, probably by inserting something at the
     # end of methods that make edits?
+    # TODO: save document.xml or document2.xml ?
     #++
     def update
       replace_entry 'word/document.xml', doc.serialize(save_with: 0)
+      update_multiple_documents :headers
+      update_multiple_documents :footers
+      update_single_document :numbering
+      # also save styles? / rels?
     end
 
+    def update_multiple_documents(attr_name)
+      self.instance_variable_get("@#{attr_name}").each do |simple_file_name, contents|
+        replace_entry("word/#{simple_file_name}.xml", contents.serialize(:save_with => 0))
+      end
+    end
+
+    def update_single_document(attr_name)
+      path = DOCUMENT_PATHS[attr_name]
+      xml_document = self.instance_variable_get("@#{attr_name}")
+      replace_entry path, xml_document.serialize(:save_with => 0) if xml_document
+    end
+
+
     # generate Elements::Containers::Paragraph from paragraph XML node
     def parse_paragraph_from(p_node)
       Elements::Containers::Paragraph.new(p_node, document_properties)