lib/io_streams/zip/reader.rb in iostreams-0.20.1 vs lib/io_streams/zip/reader.rb in iostreams-0.20.2

@@ -1,70 +1,82 @@
 module IOStreams
   module Zip
     class Reader
       # Read from a zip file or stream, decompressing the contents as it is read
       # The input stream from the first file found in the zip file is passed
-      # to the supplied block
+      # to the supplied block.
       #
+      # Parameters:
+      #   entry_file_name: [String]
+      #     Name of the file within the Zip file to read.
+      #     Default: Read the first file found in the zip file.
+      #
       # Example:
       #   IOStreams::Zip::Reader.open('abc.zip') do |io_stream|
       #     # Read 256 bytes at a time
       #     while data = io_stream.read(256)
       #       puts data
       #     end
       #   end
-      def self.open(file_name_or_io, _ = nil, &block)
-        if !defined?(JRuby) && !defined?(::Zip)
-          # MRI needs Ruby Zip, since it only has native support for GZip
-          begin
-            require 'zip'
-          rescue LoadError => exc
-            raise(LoadError, "Install gem 'rubyzip' to read and write Zip files: #{exc.message}")
-          end
-        end
-
+      def self.open(file_name_or_io, entry_file_name: nil, &block)
         # File name supplied
-        return read_file(file_name_or_io, &block) unless IOStreams.reader_stream?(file_name_or_io)
+        return read_file(file_name_or_io, entry_file_name, &block) unless IOStreams.reader_stream?(file_name_or_io)
 
-        # ZIP can only work against a file, not a stream, so create temp file.
+        # Ruby ZIP gem uses `#seek` so can only work against a file, not a stream, so create temp file.
+        # JRuby ZIP requires an InputStream.
         IOStreams::File::Path.temp_file_name('iostreams_zip') do |temp_file_name|
           IOStreams.copy(file_name_or_io, temp_file_name, target_options: {streams: []})
-          read_file(temp_file_name, &block)
+          read_file(temp_file_name, entry_file_name, &block)
         end
       end
 
       if defined?(JRuby)
         # Java has built-in support for Zip files
-        def self.read_file(file_name, &block)
+        def self.read_file(file_name, entry_file_name)
           fin = Java::JavaIo::FileInputStream.new(file_name)
           zin = Java::JavaUtilZip::ZipInputStream.new(fin)
-          zin.get_next_entry
-          block.call(zin.to_io)
+
+          get_entry(zin, entry_file_name) ||
+            raise(Java::JavaUtilZip::ZipException.new("File #{entry_file_name} not found within zip file."))
+
+          yield(zin.to_io)
         ensure
           zin.close if zin
           fin.close if fin
         end
 
       else
-
         # Read from a zip file or stream, decompressing the contents as it is read
         # The input stream from the first file found in the zip file is passed
         # to the supplied block
-        def self.read_file(file_name, &block)
-          begin
-            zin = ::Zip::InputStream.new(file_name)
-            zin.get_next_entry
-            block.call(zin)
-          ensure
+        def self.read_file(file_name, entry_file_name)
+          if !defined?(::Zip)
+            # MRI needs Ruby Zip, since it only has native support for GZip
             begin
-              zin.close if zin
-            rescue IOError
-              # Ignore file already closed errors since Zip::InputStream
-              # does not have a #closed? method
+              require 'zip'
+            rescue LoadError => exc
+              raise(LoadError, "Install gem 'rubyzip' to read and write Zip files: #{exc.message}")
             end
           end
+
+          ::Zip::InputStream.open(file_name) do |zin|
+            get_entry(zin, entry_file_name) ||
+              raise(::Zip::EntryNameError, "File #{entry_file_name} not found within zip file.")
+            yield(zin)
+          end
         end
+      end
 
+      def self.get_entry(zin, entry_file_name)
+        if entry_file_name.nil?
+          zin.get_next_entry
+          return true
+        end
+
+        while entry = zin.get_next_entry
+          return true if entry.name == entry_file_name
+        end
+        false
       end
     end
   end
 end