Class: Tap::Support::Dependencies

Inherits:
Monitor
  • Object
show all
Defined in:
lib/tap/support/dependencies.rb

Overview

Dependencies tracks Executable dependencies and results, and provides for thread-safe resolution of dependencies.

Defined Under Namespace

Classes: CircularDependencyError

Instance Method Summary collapse

Constructor Details

#initialize ⇒ Dependencies

Initializes a new Dependencies



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# File 'lib/tap/support/dependencies.rb', line 11

def initialize
  super 
  @resolve_stack = []
end

Instance Method Details

#register(instance) ⇒ Object

Thread-safe registration of instance as a dependency. During registration, instance is extended with the Dependency module. Returns self.



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# File 'lib/tap/support/dependencies.rb', line 19

def register(instance)
  synchronize do
    unless instance.kind_of?(Dependency)
      instance.extend Dependency
    end
  end
  self
end

#resolve(instance) ⇒ Object

Thread-safe resolution of the instance. Resolve checks for circular dependencies, then yields control to the block, which is responsible for the actual resolution.



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# File 'lib/tap/support/dependencies.rb', line 31

def resolve(instance)
  synchronize do
    if @resolve_stack.include?(instance)
      raise CircularDependencyError.new(@resolve_stack)
    end
    
    # mark the results at the index to prevent
    # infinite loops with circular dependencies
    @resolve_stack.push instance
    yield()
    @resolve_stack.pop
  end
  self
end