feat(packing): add packing to string and file support (#1)

Dockerfile

@@ -0,0 +1,39 @@
+FROM ubuntu:16.04
+
+RUN apt-get update
+RUN apt-get install -y software-properties-common python-software-properties
+RUN add-apt-repository -y ppa:ubuntu-toolchain-r/test
+RUN apt-get update
+RUN DEBIAN_FRONTEND=noninteractive apt-get -yq install gcc-7 g++-7 git curl make libssl-dev libreadline-dev zlib1g-dev
+
+RUN update-alternatives --quiet \
+  --install /usr/bin/gcc gcc /usr/bin/gcc-7 10 \
+  --slave /usr/bin/g++ g++ /usr/bin/g++-7 \
+  --slave /usr/bin/gcov gcov /usr/bin/gcov-7
+RUN update-alternatives --quiet --set gcc /usr/bin/gcc-7
+
+RUN apt-get install -y bzip2
+RUN apt-get install -y build-essential
+# ruby
+RUN git clone https://github.com/rbenv/rbenv.git /usr/local/.rbenv
+ENV PATH /usr/local/.rbenv/bin:$PATH
+RUN eval "$(rbenv init -)"
+
+RUN git clone https://github.com/rbenv/ruby-build.git ~/.rbenv/plugins/ruby-build
+RUN echo 'export PATH="$HOME/.rbenv/plugins/ruby-build/bin:$PATH"' >> ~/.bashrc
+RUN export PATH="$HOME/.rbenv/plugins/ruby-build/bin:$PATH"
+RUN rbenv install 2.4.1 && rbenv global 2.4.1
+RUN apt-get install -y ruby-full
+
+RUN gem install bundler -v 1.16.0ex
+RUN rbenv rehash
+
+RUN curl -O https://capnproto.org/capnproto-c++-0.6.1.tar.gz \
+    && tar zxf capnproto-c++-0.6.1.tar.gz \
+    && cd capnproto-c++-0.6.1 \
+    && ./configure \
+    && make -j6 check \
+    && make install
+
+RUN ln -sf /usr/bin/g++-7 /usr/bin/g++ && ln -sf /usr/bin/gcc-7 /usr/bin/gcc
+

ext/capn_proto/dynamic_struct_builder.cc

@@ -8,6 +8,7 @@
 #include "class_builder.h"
 #include "exception.h"
 #include "util.h"
+#include "rb_str_output_stream.h"
 
 namespace ruby_capn_proto {
   using WrappedType = capnp::DynamicStruct::Builder;
@@ -18,6 +19,9 @@ namespace ruby_capn_proto {
       defineAlloc(&alloc).
       defineMethod("which", &which).
       defineMethod("write", &write).
+      defineMethod("write_packed", &write_packed).
+      defineMethod("to_packed_string", &to_packed_string).
+      defineMethod("to_string", &to_string).
       defineMethod("to_bytes", &to_bytes).
       defineMethod("[]", &get).
       defineMethod("[]=", &set).
@@ -148,7 +152,62 @@ namespace ruby_capn_proto {
     }
   }
 
-  VALUE DynamicStructBuilder::to_bytes(VALUE self) {
+  VALUE DynamicStructBuilder::write_packed(VALUE self, VALUE file) {
+    VALUE rb_fileno = rb_funcall(file, rb_intern("fileno"), 0);
+    int fileno = FIX2INT(rb_fileno);
+    if (!RTEST(rb_iv_get(self, "is_root"))) {
+      rb_raise(Exception::Class, "You can only call write_packed() on the message's root struct.");
+    }
+
+    capnp::MessageBuilder* message_builder = MallocMessageBuilder::unwrap(rb_iv_get(self, "parent"));
+    try {
+      capnp::writePackedMessageToFd(fileno, message_builder->getSegmentsForOutput());
+      return Qnil;
+    } catch (kj::Exception ex) {
+      return Exception::raise(ex);
+    }
+  }
+
+  VALUE DynamicStructBuilder::to_string(VALUE self, VALUE str) {
+    if (!RTEST(rb_iv_get(self, "is_root")))
+    {
+      rb_raise(Exception::Class, "You can only call write_packed() on the message's root struct.");
+    }
+
+    auto str_output = new RbStrOutputStream(str);
+    capnp::MessageBuilder *message_builder = MallocMessageBuilder::unwrap(rb_iv_get(self, "parent"));
+    try
+    {
+      capnp::writeMessage(*str_output, message_builder->getSegmentsForOutput());
+      return Qnil;
+    }
+    catch (kj::Exception ex)
+    {
+      return Exception::raise(ex);
+    }
+  }
+
+  VALUE DynamicStructBuilder::to_packed_string(VALUE self, VALUE str) {
+    if (!RTEST(rb_iv_get(self, "is_root")))
+    {
+      rb_raise(Exception::Class, "You can only call write_packed() on the message's root struct.");
+    }
+
+    auto str_output = new RbStrOutputStream(str);
+    capnp::MessageBuilder *message_builder = MallocMessageBuilder::unwrap(rb_iv_get(self, "parent"));
+    try
+    {
+      capnp::writePackedMessage(*str_output, message_builder->getSegmentsForOutput());
+      return Qnil;
+    }
+    catch (kj::Exception ex)
+    {
+      return Exception::raise(ex);
+    }
+  }
+
+  VALUE DynamicStructBuilder::to_bytes(VALUE self)
+  {
     if (!RTEST(rb_iv_get(self, "is_root"))) {
       rb_raise(Exception::Class, "You can only call to_bytes() on the message's root struct.");
     }

ext/capn_proto/dynamic_struct_builder.h

@@ -20,6 +20,9 @@ namespace ruby_capn_proto {
     static VALUE init(int argc, VALUE* argv, VALUE self);
 
     static VALUE write(VALUE self, VALUE file);
+    static VALUE write_packed(VALUE self, VALUE file);
+    static VALUE to_packed_string(VALUE self, VALUE str);
+    static VALUE to_string(VALUE self, VALUE str);
     static VALUE to_bytes(VALUE self);
 
     static VALUE Class;

ext/capn_proto/rb_str_output_stream.cc

@@ -0,0 +1,12 @@
+#include "ruby_capn_proto.h"
+#include "rb_str_output_stream.h"
+
+namespace ruby_capn_proto {
+  RbStrOutputStream::~RbStrOutputStream() noexcept(false) {}
+
+  void RbStrOutputStream::write(const void *buffer, size_t size)
+  {
+    const char *pos = reinterpret_cast<const char *>(buffer);
+    rb_str_cat(str, pos, size);
+  }
+}

ext/capn_proto/rb_str_output_stream.h

@@ -0,0 +1,24 @@
+#ifndef RB_STR_OUTPUT_STREAM_H
+#define RB_STR_OUTPUT_STREAM_H
+
+#include "ruby_capn_proto.h"
+#include "kj/io.h"
+
+namespace ruby_capn_proto
+{
+  class RbStrOutputStream : public kj::OutputStream {
+      // An OutputStream wrapping string buffer
+
+    public:
+      explicit RbStrOutputStream(VALUE str) : str(str) {}
+      KJ_DISALLOW_COPY(RbStrOutputStream);
+      ~RbStrOutputStream() noexcept(false);
+
+      void write(const void *buffer, size_t size) override;
+
+    private:
+      VALUE str;
+  };
+}
+
+#endif /* RB_STR_OUTPUT_STREAM_H */

lib/capn_proto/version.rb

@@ -1,3 +1,3 @@
 module CapnProto
-  VERSION = "0.0.1.alpha.8"
+  VERSION = "0.0.1.alpha.9"
 end

spec/capn_proto_spec.rb

@@ -64,6 +64,27 @@ module AddressBook extend CapnProto::SchemaLoader
     end
   end
 
+  describe "#to_string" do
+    it "writes the message to a string" do
+      addresses = AddressBook::AddressBook.new_message
+      people = addresses.initPeople(1)
+      bob = people[0]
+      bob.name = "Bob"
+      bob.id = 123
+      str = ""
+      addresses.to_string(str)
+
+      tmp = Tempfile.new('test.bin')
+      tmp << str
+      tmp.rewind
+
+      addresses = AddressBook::AddressBook.read_from(tmp)
+      expect(addresses.people.size).to eq 1
+      expect(addresses.people.first.name).to eq "Bob"
+      expect(addresses.people.first.id).to eq 123
+    end
+  end
+
   describe "Dynamic Structs" do
     let(:addresses) { AddressBook::AddressBook.new_message }