Add support for resetting the parser

ffi/README.md

@@ -33,5 +33,5 @@ parser << "GET / HTTP/1.1\r\n\r\n"
 
 # Reset the parser for the next request:
 #
-parser.finish
+parser.reset
 ```

ffi/lib/llhttp.rb

@@ -45,4 +45,5 @@ class Callbacks < FFI::Struct
   attach_function :llhttp_get_error_reason, [:pointer], :string
   attach_function :llhttp_should_keep_alive, [:pointer], :int
   attach_function :llhttp_finish, [:pointer], :int
+  attach_function :llhttp_reset, [:pointer], :void
 end

ffi/lib/llhttp/parser.rb

@@ -117,12 +117,18 @@ def keep_alive?
       LLHttp.llhttp_should_keep_alive(@pointer) == 1
     end
 
-    # [public] Get ready to parse the next request.
+    # [public] Tells the parser we are finished.
     #
     def finish
       LLHttp.llhttp_finish(@pointer)
     end
 
+    # [public] Get ready to parse the next request/response.
+    #
+    def reset
+      LLHttp.llhttp_reset(@pointer)
+    end
+
     CALLBACKS.each do |callback|
       class_eval(
         <<~RB, __FILE__, __LINE__ + 1

mri/README.md

@@ -33,5 +33,5 @@ parser << "GET / HTTP/1.1\r\n\r\n"
 
 # Reset the parser for the next request:
 #
-parser.finish
+parser.reset
 ```

mri/ext/llhttp/llhttp_ext.c

@@ -154,6 +154,18 @@ VALUE rb_llhttp_finish(VALUE self) {
   return Qtrue;
 }
 
+VALUE rb_llhttp_reset(VALUE self) {
+  llhttp_t *parser;
+
+  Data_Get_Struct(self, llhttp_t, parser);
+
+  llhttp_settings_t *settings = parser->settings;
+
+  llhttp_reset(parser);
+
+  return Qtrue;
+}
+
 VALUE rb_llhttp_content_length(VALUE self) {
   llhttp_t *parser;
 
@@ -301,6 +313,7 @@ void Init_llhttp_ext(void) {
   rb_define_method(cParser, "<<", rb_llhttp_parse, 1);
   rb_define_method(cParser, "parse", rb_llhttp_parse, 1);
   rb_define_method(cParser, "finish", rb_llhttp_finish, 0);
+  rb_define_method(cParser, "reset", rb_llhttp_reset, 0);
 
   rb_define_method(cParser, "content_length", rb_llhttp_content_length, 0);
   rb_define_method(cParser, "method_name", rb_llhttp_method_name, 0);

mri/lib/llhttp/parser.rb

@@ -30,6 +30,10 @@ module LLHttp
   #
   #   Call `LLHttp::Parser#finish` when processing is complete for the current request or response.
   #
+  # Resetting
+  #
+  #   Call `LLHttp::Parser#reset` to reset the parser for the next request or response.
+  #
   class Parser
     LLHTTP_TYPES = {both: 0, request: 1, response: 2}.freeze
 

spec/acceptance/support/server.rb

@@ -49,7 +49,7 @@ def run
   ensure
     stream.close
 
-    @parser.finish
+    @parser.reset
   end
 
   private def parse_next(stream)

spec/integration/no_content_length_spec.rb

@@ -0,0 +1,64 @@
+# frozen_string_literal: true
+
+require_relative "support/context/parsing"
+
+RSpec.describe "parsing responses without a content length" do
+  include_context "parsing"
+
+  shared_examples "examples" do
+    let(:extension) {
+      proc {
+        def on_message_begin
+          @calls << :on_message_begin
+        end
+
+        def on_header_field(_)
+          @calls << :on_header_field
+        end
+
+        def on_header_value(_)
+          @calls << :on_header_value
+        end
+
+        def on_headers_complete
+          @calls << :on_headers_complete
+        end
+
+        def on_body(_)
+          @calls << :on_body
+        end
+
+        def on_message_complete
+          @calls << :on_message_complete
+        end
+      }
+    }
+
+    it "parses correctly" do
+      10_000.times do
+        parse
+
+        instance.reset
+      end
+
+      expect(delegate.calls.count(:on_message_begin)).to eq(10_000)
+      expect(delegate.calls.count(:on_header_field)).to eq(0)
+      expect(delegate.calls.count(:on_header_value)).to eq(0)
+      expect(delegate.calls.count(:on_headers_complete)).to eq(10_000)
+      expect(delegate.calls.count(:on_body)).to eq(0)
+      expect(delegate.calls.count(:on_message_complete)).to eq(0)
+    end
+  end
+
+  context "response" do
+    let(:type) {
+      :response
+    }
+
+    let(:fixture) {
+      :response_sans_content_length
+    }
+
+    include_examples "examples"
+  end
+end

spec/integration/reusing_spec.rb

@@ -38,7 +38,7 @@ def on_message_complete
       10_000.times do
         parse
 
-        instance.finish
+        instance.reset
       end
 
       expect(delegate.calls.count(:on_message_begin)).to eq(10_000)

spec/integration/support/context/parsing.rb

@@ -101,6 +101,10 @@ def initialize(context)
         "body2\n",
         "body3\n",
         "\r\n"
+      ],
+
+      response_sans_content_length: [
+        "HTTP/1.1 200 OK\r\n\r\n"
       ]
     }
   }