Merge branch 'topic/refactor-for-0.3'

* topic/refactor-for-0.3:
  examples: static_server: use test certificate in test/
  style: prefer "".b over String.new
  frame: settings: add Frame::Settings.ack
  avoid Frame#type if possible
  client: decoders: unfreeze Client::Decoders::DECODERS
  frame: create subclasses for each frame type
  merge *_{utils,factory}

1 files changed, 51 insertions, 38 deletions

diff --git a/lib/plum/frame.rb b/lib/plum/frame.rb
index bf61629..1a4b402 100644
--- a/lib/plum/frame.rb
+++ b/lib/plum/frame.rb
@@ -1,12 +1,8 @@
 # frozen-string-literal: true
 
 using Plum::BinaryString
-
 module Plum
   class Frame
-    extend FrameFactory
-    include FrameUtils
-
     FRAME_TYPES = {
       data:           0x00,
       headers:        0x01,
@@ -56,14 +52,10 @@ module Plum
     # @!visibility private
     FRAME_FLAGS_MAP = FRAME_FLAGS.values.inject(:merge).freeze
 
-    SETTINGS_TYPE = {
-      header_table_size:      0x01,
-      enable_push:            0x02,
-      max_concurrent_streams: 0x03,
-      initial_window_size:    0x04,
-      max_frame_size:         0x05,
-      max_header_list_size:   0x06
-    }.freeze
+    # type_value = 0x00 - 0x09 are known, but these classes aren't defined yet...
+    # Frame.register_subclass adds them.
+    SUB_CLASSES = []
+    private_constant :SUB_CLASSES
 
     # RFC7540: 4.1 Frame format
     # +-----------------------------------------------+
@@ -85,12 +77,29 @@ module Plum
     # [String] The payload. Value is frozen.
     attr_reader :payload
 
-    def initialize(type: nil, type_value: nil, flags: nil, flags_value: nil, stream_id: nil, payload: nil)
+    # @private
+    protected def initialize_base(type: nil, type_value: nil, flags: nil, flags_value: nil, stream_id: nil, payload: nil)
       @payload = payload || ""
       @length = @payload.bytesize
-      @type_value = type_value or self.type = type
+      @type_value = type_value || FRAME_TYPES[type] or raise ArgumentError.new("unknown frame type: #{type}")
       @flags_value = flags_value or self.flags = flags
       @stream_id = stream_id or raise ArgumentError.new("stream_id is necessary")
+      self
+    end
+
+    # @private
+    def initialize(*, **)
+      raise ArgumentError, "can't instantiate abstract class"
+    end
+
+    # Creates a new instance of Frame or an subclass of Frame.
+    # @private
+    def self.craft(type: nil, type_value: nil, **args)
+      type_value ||= type && FRAME_TYPES[type] or (raise ArgumentError, "unknown frame type")
+      klass = SUB_CLASSES[type_value] || Frame::Unknown
+      instance = klass.allocate
+      instance.send(:initialize_base, type_value: type_value, **args)
+      instance
     end
 
     # Returns the length of payload.
@@ -105,12 +114,6 @@ module Plum
       FRAME_TYPES_INVERSE[@type_value] || ("unknown_%02x" % @type_value).to_sym
     end
 
-    # Sets the frame type.
-    # @param value [Symbol] The type.
-    def type=(value)
-      @type_value = FRAME_TYPES[value] or raise ArgumentError.new("unknown frame type: #{value}")
-    end
-
     # Returns the set flags on the frame.
     # @return [Array<Symbol>] The flags.
     def flags
@@ -150,26 +153,36 @@ module Plum
 
     # @private
     def inspect
-      "#<Plum::Frame:0x%04x} length=%d, type=%p, flags=%p, stream_id=0x%04x, payload=%p>" % [__id__, length, type, flags, stream_id, payload]
+      "#<%s:0x%04x length=%d, flags=%p, stream_id=0x%04x, payload=%p>" % [self.class, __id__, length, flags, stream_id, payload]
     end
 
-    # Parses a frame from given buffer. It changes given buffer.
-    # @param buffer [String] The buffer stored the data received from peer. Encoding must be Encoding::BINARY.
-    # @return [Frame, nil] The parsed frame or nil if the buffer is imcomplete.
-    def self.parse!(buffer)
-      return nil if buffer.bytesize < 9 # header: 9 bytes
-      length = buffer.uint24
-      return nil if buffer.bytesize < 9 + length
-
-      cur = buffer.byteshift(9 + length)
-      type_value, flags_value, r_sid = cur.byteslice(3, 6).unpack("CCN")
-      # r = r_sid >> 31 # currently not used
-      stream_id = r_sid # & ~(1 << 31)
-
-      self.new(type_value: type_value,
-               flags_value: flags_value,
-               stream_id: stream_id,
-               payload: cur.byteslice(9, length)).freeze
+    class << self
+      # Parses a frame from given buffer. It changes given buffer.
+      # @param buffer [String] The buffer stored the data received from peer. Encoding must be Encoding::BINARY.
+      # @return [Frame, nil] The parsed frame or nil if the buffer is imcomplete.
+      def parse!(buffer)
+        return nil if buffer.bytesize < 9 # header: 9 bytes
+        length = buffer.uint24
+        return nil if buffer.bytesize < 9 + length
+
+        cur = buffer.byteshift(9 + length)
+        type_value, flags_value, r_sid = cur.byteslice(3, 6).unpack("CCN")
+        # r = r_sid >> 31 # currently not used
+        stream_id = r_sid # & ~(1 << 31)
+
+        frame = (SUB_CLASSES[type_value] || Frame::Unknown).allocate
+        frame.send(:initialize_base,
+                   type_value: type_value,
+                   flags_value: flags_value,
+                   stream_id: stream_id,
+                   payload: cur.byteslice(9, length))
+        frame.freeze
+      end
+
+      # Sub classes must call this.
+      protected def register_subclass(type_value)
+        SUB_CLASSES[type_value] = self
+      end
     end
   end
 end