Implement prototype of flexible hook handler class

[syucream]

https://github.com/syucream/ts_mruby/issues/36

• [x] Separate logic related to thread shared/local data.
• [x] Add a new class, load handler and insert appropriate hook plugins.
• [x] Refactoring.

- [ ] Modify unit test code will be fixed by https://github.com/syucream/ts_mruby/issues/75

[coveralls]

Coverage decreased (-51.7%) to 0.0% when pulling bf60a27d788e46fb7085626198ce64fbdf5b861a on feature/hook_prototype into f4b525abec1c66790b5f1ff4f83ce13bfecb4b4a on master.

[syucream]

Idea notes

Requirements

• low memory consumption
• safely memory access

Idea

• Enforce users to create their handler class(or module?). For example:

module MyEventHandler
  def on_send_request_hdr
    ...
  end
end

• Generate new obj of the class from current thread-local mrb_state.
  • Avoid to create new mrb_state.
  • Is it unsafely access?
• To avoid unexpected GC, I must mark the new obj.
  • Stop GC temporarily by calling mrb_gc_register()
  • And restart GC by calling mrb_gc_unregister()
  • It has a risk of missing mrb_gc_unregister() so I should take RAII approach, for example using shared_ptr.
• Insert a new TransactionPlugin registers hooks and has hook handler functions.
  • Execute the obj by calling mrb_funcall_*()

[syucream]

progress

Tried to fix https://github.com/syucream/ts_mruby/pull/74#issuecomment-245333055 by https://github.com/syucream/ts_mruby/pull/74/commits/c753613bd2a279c656d9e2aebfb3024153129dc6.

new issue

• Detect unusable class/method usage.
  • For example, ATS::echo is unavailable at late hook.
  • Should these calling raise an exception?

[coveralls]

Coverage decreased (-51.7%) to 0.0% when pulling 98dacd8097e3f083dfc414f11ad693eb46030b3a on feature/hook_prototype into f4b525abec1c66790b5f1ff4f83ce13bfecb4b4a on master.

[coveralls]

Coverage decreased (-51.7%) to 0.0% when pulling 98dacd8097e3f083dfc414f11ad693eb46030b3a on feature/hook_prototype into f4b525abec1c66790b5f1ff4f83ce13bfecb4b4a on master.

[syucream]

To detect unusable class/method usage, plugin must pass hook timing to the transaction because atscppapi::Transaction doesn't have hook info API.

[coveralls]

Coverage decreased (-51.7%) to 0.0% when pulling 42bf9bb610e6a0a2d88a6c6cc107207d02f98a41 on feature/hook_prototype into f4b525abec1c66790b5f1ff4f83ce13bfecb4b4a on master.

[coveralls]

Coverage decreased (-51.7%) to 0.0% when pulling 54f187d75a12e9b03dfa12aa01bbe50d8dcb2460 on feature/hook_prototype into f4b525abec1c66790b5f1ff4f83ce13bfecb4b4a on master.

[syucream]

TSMrubyValue implemented at https://github.com/syucream/ts_mruby/pull/74/commits/c753613bd2a279c656d9e2aebfb3024153129dc6 has non-thread-safe function. At https://github.com/syucream/ts_mruby/pull/74/commits/a5dd1068b5c75a190376ee1e43930abf15edd63d, I try implementing an another approach.

[coveralls]

Coverage decreased (-51.7%) to 0.0% when pulling a5dd1068b5c75a190376ee1e43930abf15edd63d on feature/hook_prototype into f4b525abec1c66790b5f1ff4f83ce13bfecb4b4a on master.

[coveralls]

Coverage decreased (-51.7%) to 0.0% when pulling 5ba68e871f3f07289b9c712af92220325613e7d1 on feature/hook_prototype into f4b525abec1c66790b5f1ff4f83ce13bfecb4b4a on master.

[syucream]

Modify unit test code

Its a big task. I fix it as another issue. https://github.com/syucream/ts_mruby/issues/75

[coveralls]

Coverage decreased (-51.7%) to 0.0% when pulling 706c841cb183352d82fe032edc97ed219113caf2 on feature/hook_prototype into f4b525abec1c66790b5f1ff4f83ce13bfecb4b4a on master.

[coveralls]

Coverage decreased (-51.7%) to 0.0% when pulling a999df433edabb6148096ea51ecc1dc8690d0e30 on feature/hook_prototype into f4b525abec1c66790b5f1ff4f83ce13bfecb4b4a on master.