1 files changed, 79 insertions, 0 deletions
diff --git a/lib/rdoc/encoding.rb b/lib/rdoc/encoding.rb
new file mode 100644
index 0000000000..4f0779881c
--- /dev/null
+++ b/lib/rdoc/encoding.rb
@@ -0,0 +1,79 @@
+require 'rdoc'
+
+##
+# This class is a wrapper around File IO and Encoding that helps RDoc load
+# files and convert them to the correct encoding.
+
+module RDoc::Encoding
+
+  ##
+  # Reads the contents of +filename+ and handles any encoding directives in
+  # the file.
+  #
+  # The content will be converted to the +encoding+.  If the file cannot be
+  # converted a warning will be printed and nil will be returned.
+
+  def self.read_file filename, encoding
+    content = open filename, "rb" do |f| f.read end
+
+    utf8 = content.sub!(/\A\xef\xbb\xbf/, '')
+
+    RDoc::Encoding.set_encoding content
+
+    if Object.const_defined? :Encoding then
+      encoding ||= Encoding.default_external
+      orig_encoding = content.encoding
+
+      if utf8 then
+        content.force_encoding Encoding::UTF_8
+        content.encode! encoding
+      else
+        # assume the content is in our output encoding
+        content.force_encoding encoding
+      end
+
+      unless content.valid_encoding? then
+        # revert and try to transcode
+        content.force_encoding orig_encoding
+        content.encode! encoding
+      end
+
+      unless content.valid_encoding? then
+        warn "unable to convert #{filename} to #{encoding}, skipping"
+        content = nil
+      end
+    end
+
+    content
+  rescue ArgumentError => e
+    raise unless e.message =~ /unknown encoding name - (.*)/
+    warn "unknown encoding name \"#{$1}\" for #{filename}, skipping"
+    nil
+  rescue Encoding::UndefinedConversionError => e
+    warn "unable to convert #{e.message} for #{filename}, skipping"
+    nil
+  rescue Errno::EISDIR, Errno::ENOENT
+    nil
+  end
+
+  ##
+  # Sets the encoding of +string+ based on the magic comment
+
+  def self.set_encoding string
+    return unless Object.const_defined? :Encoding
+
+    first_line = string[/\A(?:#!.*\n)?.*\n/]
+
+    name = case first_line
+           when /^<\?xml[^?]*encoding=(["'])(.*?)\1/ then $2
+           when /\b(?:en)?coding[=:]\s*([^\s;]+)/i   then $1
+           else                                           return
+           end
+
+    enc = Encoding.find name
+    string.force_encoding enc if enc
+  end
+
+end
+
+