Class: Dommy::Js::HandleTable

Inherits:
Object
  • Object
show all
Defined in:
lib/dommy/js/handle_table.rb

Overview

Maps JS-facing integer handles to live Ruby objects. Engine-agnostic.

Handles are monotonic — never reused — so a handle can never refer to two different objects over the table’s lifetime. That invariant is what makes GC-driven #release race-free: a finalizer releasing handle N can’t clobber a different object that happened to get the same id.

The same Ruby object reuses its handle while still registered (keyed by object_id), so it maps to a single JS proxy (stable identity). A registry entry also keeps the object reachable while JS holds a proxy for it.

Instance Method Summary collapse

Constructor Details

#initialize ⇒ HandleTable

Returns a new instance of HandleTable.



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# File 'lib/dommy/js/handle_table.rb', line 16

def initialize
  @by_handle = {}      # handle (Integer) -> object
  @handle_by_oid = {}  # object_id -> handle (for identity reuse)
  @next_handle = 0
end

Instance Method Details

#fetch(handle) ⇒ Object 



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# File 'lib/dommy/js/handle_table.rb', line 33

def fetch(handle)
  @by_handle.fetch(handle.to_i)
end

#register(obj) ⇒ Object 



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# File 'lib/dommy/js/handle_table.rb', line 22

def register(obj)
  oid = obj.object_id
  existing = @handle_by_oid[oid]
  return existing if existing && @by_handle[existing].equal?(obj)

  handle = (@next_handle += 1)
  @by_handle[handle] = obj
  @handle_by_oid[oid] = handle
  handle
end

#release(handle) ⇒ Object

Forget a handle (called when its JS proxy is garbage-collected). Only trims the mapping; the object itself lives on via its other references.



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# File 'lib/dommy/js/handle_table.rb', line 39

def release(handle)
  obj = @by_handle.delete(handle.to_i)
  return unless obj

  oid = obj.object_id
  @handle_by_oid.delete(oid) if @handle_by_oid[oid] == handle.to_i
end

#size ⇒ Object 



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# File 'lib/dommy/js/handle_table.rb', line 47

def size
  @by_handle.size
end