1 files changed, 33 insertions, 0 deletions
diff --git a/lib/plum/frame/push_promise.rb b/lib/plum/frame/push_promise.rb
new file mode 100644
index 0000000..e07b8e6
--- /dev/null
+++ b/lib/plum/frame/push_promise.rb
@@ -0,0 +1,33 @@
+# frozen-string-literal: true
+
+using Plum::BinaryString
+module Plum
+  class Frame::PushPromise < Frame
+    register_subclass 0x05
+
+    # Creates a PUSH_PROMISE frame.
+    # @param stream_id [Integer] The stream ID.
+    # @param new_id [Integer] The stream ID to create.
+    # @param encoded [String] Request headers.
+    # @param end_headers [Boolean] add END_HEADERS flag
+    def initialize(stream_id, new_id, encoded, end_headers: false)
+      payload = String.new.push_uint32(new_id)
+                          .push(encoded)
+      fval = end_headers ? 4 : 0
+      initialize_base(type: :push_promise, stream_id: stream_id, flags_value: fval, payload: payload)
+    end
+
+    # Splits this frame into multiple frames not to exceed MAX_FRAME_SIZE.
+    # @param max [Integer] The maximum size of a frame payload.
+    # @yield [Frame] The splitted frames.
+    def split(max)
+      return yield self if @length <= max
+      first, *mid, last = @payload.chunk(max)
+      yield Frame.craft(type_value: @type_value, stream_id: @stream_id, payload: first, flags_value: @flags_value & ~4)
+      mid.each { |slice|
+        yield Frame.craft(type: :continuation, stream_id: @stream_id, payload: slice, flags_value: 0)
+      }
+      yield Frame.craft(type: :continuation, stream_id: @stream_id, payload: last, flags_value: @flags_value & 4)
+    end
+  end
+end