Upgrade to v8 4.5, move towards 1.0 release

[cowboyd]

This PR upgrades the version of V8 used by The Ruby Racer in order to take advantage of the significantly improved embedding APIs that it exposes. This allows us to address the long-standing stability issues that have plagued the pre-releases. It will basis of a 1.0 release.

• [x] upgrade libv8 to modern version https://github.com/cowboyd/libv8/pull/178
• [x] implement memory reference queues to coordinate garbage collection
• [x] implement V8::C::External values with robust memory handling.
• [ ] test cases for memory leakage
• [x] Implement Maybe handling #364
• [ ] move away from all deprecated non-Maybe apis
• [x] finish V8::C::Object implementation - #377
• [x] finish V8::C::Array implementation #381
• [ ] implement ObjectTemplate
  • [ ] Signature and AccessorSignature
  • [ ] SetHandler() (named properties and indexed properties)
  • [ ] SetCallAsFunctionHandler
• [ ] implement FunctionTemplate
  • [ ] basic methods: New, SetLength, InstanceTemplate, Inherit, PrototypeTemplate, etc...
  • [ ] implement SetCallHandler
• [x] exception handling, try catch, etc... #379
• [ ] implement Pre-emption apis in the isolate (TerminateExecution, et al.) #382
• [ ] re-work high-level Ruby API on top of new C layer
• [ ] investigate concurrent queues that do not require c++11
• [ ] decide on final support matrix (ruby version, ruby implementation, C compiler, etc...)
• [ ] final pass on code-style and organization
  • [ ] documentation in missing areas
  • [ ] extract as much into header files
  • [ ] use lambas if we go the c++11 route.

[ignisf]

Since [1] V8 finally assumes that v8/include is in the include path.

[1] https://chromium.googlesource.com/v8/v8/+/e8c914f18fd88cd58aaaf5d8cee53b9e57477b52

The following patch should be applied before moving on to V8 5.1+:

diff --git a/ext/v8/rr.h b/ext/v8/rr.h
index 37a5e4d..373a80a 100644
--- a/ext/v8/rr.h
+++ b/ext/v8/rr.h
@@ -1,9 +1,8 @@
 #ifndef THE_RUBY_RACER
 #define THE_RUBY_RACER

-#include <include/v8.h>
-#include <include/libplatform/libplatform.h>
-
+#include <v8.h>
+#include <libplatform/libplatform.h>
 #include <ruby.h>
 #include <vector>
 #ifdef HAVE_RUBY_ENCODING_H

[wk8]

Hey, is this still actively being worked on? :)

[ignisf]

Right now, no. @cowboyd was planning to work on this some more this month, not sure how his plans are holding up though.

[wk8]

@ignisf : thanks for the info :)

[JayTeeSF]

This gem (and the less gem(s)) are great. Thanks for all you've done to make this work. By any chance are there still plans to update this gem to use a newer (faster) v8?

[dojutsu-user]

Is this still active?

[cowboyd]

Is this still active?

I do not actively work on this gem anymore. mini_racer is under active development and shares most of the use-cases.

[0xdevalias]

I do not actively work on this gem anymore. mini_racer is under active development and shares most of the use-cases.

@cowboyd it would be good to update the README.md saying as much so that information is front/centre when people come to the repo. And maybe also creating a pinned issue about it, to centralize any discussions/desires people may have to continue work on it as a community.