Merge branch 'Advanon-chores/refactor-callback-invokers'

aasm · Jul 30, 2018 · b5e71b0 · b5e71b0
2 parents 35d6f68 + 89544e5
commit b5e71b0
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diff --git a/README.md b/README.md
@@ -130,16 +130,26 @@ the transition succeeds :
 
 ### Callbacks
 
-You can define a number of callbacks for your transitions. These methods will be
+You can define a number of callbacks for your events, transitions and states. These methods, Procs or classes will be
 called when certain criteria are met, like entering a particular state:
 
 ```ruby
+class LogRunTime
+  def initialize(resource)
+    @resource = resource
+  end
+
+  def call
+    # Do whatever you want with @resource
+  end
+end
+
 class Job
   include AASM
 
   aasm do
     state :sleeping, :initial => true, :before_enter => :do_something
-    state :running
+    state :running, before_enter: Proc.new { do_something && notify_somebody }
     state :finished
 
     after_all_transitions :log_status_change
@@ -195,6 +205,8 @@ is finished.
 
 AASM will also initialize `LogRunTime` and run the `call` method for you after the transition from `running` to `finished` in the example above. You can pass arguments to the class by defining an initialize method on it, like this:
 
+Note that Procs are executed in the context of a record, it means that you don't need to expect the record as an argument, just call the methods you need.
+
 ```ruby
 class LogRunTime
   # optional args parameter can be omitted, but if you define initialize

diff --git a/lib/aasm.rb b/lib/aasm.rb
@@ -9,6 +9,11 @@
 require 'aasm/core/transition'
 require 'aasm/core/event'
 require 'aasm/core/state'
+require 'aasm/core/invoker'
+require 'aasm/core/invokers/base_invoker'
+require 'aasm/core/invokers/class_invoker'
+require 'aasm/core/invokers/literal_invoker'
+require 'aasm/core/invokers/proc_invoker'
 require 'aasm/localizer'
 require 'aasm/state_machine_store'
 require 'aasm/state_machine'

diff --git a/lib/aasm/core/event.rb b/lib/aasm/core/event.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module AASM::Core
   class Event
     include DslHelper
@@ -156,27 +158,9 @@ def _fire(obj, options={}, to_state=::AASM::NO_VALUE, *args)
     end
 
     def invoke_callbacks(code, record, args)
-      case code
-        when Symbol, String
-          unless record.respond_to?(code, true)
-            raise NoMethodError.new("NoMethodError: undefined method `#{code}' for #{record.inspect}:#{record.class}")
-          end
-          arity = record.__send__(:method, code.to_sym).arity
-          record.__send__(code, *(arity < 0 ? args : args[0...arity]))
-          true
-
-        when Proc
-          arity = code.arity
-          record.instance_exec(*(arity < 0 ? args : args[0...arity]), &code)
-          true
-
-        when Array
-          code.each {|a| invoke_callbacks(a, record, args)}
-          true
-
-        else
-          false
-      end
+      Invoker.new(code, record, args)
+             .with_default_return_value(false)
+             .invoke
     end
   end
 end # AASM
diff --git a/lib/aasm/core/invoker.rb b/lib/aasm/core/invoker.rb
@@ -0,0 +1,129 @@
+# frozen_string_literal: true
+
+module AASM
+  module Core
+    ##
+    # main invoker class which encapsulates the logic
+    # for invoking literal-based, proc-based, class-based
+    # and array-based callbacks for different entities.
+    class Invoker
+      DEFAULT_RETURN_VALUE = true
+
+      ##
+      # Initialize a new invoker instance.
+      # NOTE that invoker must be used per-subject/record
+      #      (one instance per subject/record)
+      #
+      # ==Options:
+      #
+      # +subject+ - invoking subject, may be Proc,
+      #             Class, String, Symbol or Array
+      # +record+  - invoking record
+      # +args+    - arguments which will be passed to the callback
+
+      def initialize(subject, record, args)
+        @subject = subject
+        @record = record
+        @args = args
+        @options = {}
+        @failures = []
+        @default_return_value = DEFAULT_RETURN_VALUE
+      end
+
+      ##
+      # Pass additional options to concrete invoker
+      #
+      # ==Options:
+      #
+      # +options+ - hash of options which will be passed to
+      #             concrete invokers
+      #
+      # ==Example:
+      #
+      # with_options(guard: proc {...})
+
+      def with_options(options)
+        @options = options
+        self
+      end
+
+      ##
+      # Collect failures to a specified buffer
+      #
+      # ==Options:
+      #
+      # +failures+ - failures buffer to collect failures
+
+      def with_failures(failures)
+        @failures = failures
+        self
+      end
+
+      ##
+      # Change default return value of #invoke method
+      # if none of invokers processed the request.
+      #
+      # The default return value is #DEFAULT_RETURN_VALUE
+      #
+      # ==Options:
+      #
+      # +value+ - default return value for #invoke method
+
+      def with_default_return_value(value)
+        @default_return_value = value
+        self
+      end
+
+      ##
+      # Find concrete invoker for specified subject and invoker it,
+      # or return default value set by #DEFAULT_RETURN_VALUE or
+      # overridden by #with_default_return_value
+
+      # rubocop:disable Metrics/AbcSize
+      def invoke
+        return invoke_array if subject.is_a?(Array)
+        return literal_invoker.invoke if literal_invoker.may_invoke?
+        return proc_invoker.invoke if proc_invoker.may_invoke?
+        return class_invoker.invoke if class_invoker.may_invoke?
+        default_return_value
+      end
+      # rubocop:enable Metrics/AbcSize
+
+      private
+
+      attr_reader :subject, :record, :args, :options, :failures,
+                  :default_return_value
+
+      def invoke_array
+        return subject.all? { |item| sub_invoke(item) } if options[:guard]
+        return subject.all? { |item| !sub_invoke(item) } if options[:unless]
+        subject.map { |item| sub_invoke(item) }
+      end
+
+      def sub_invoke(new_subject)
+        self.class.new(new_subject, record, args)
+            .with_failures(failures)
+            .with_options(options)
+            .invoke
+      end
+
+      def proc_invoker
+        @proc_invoker ||= Invokers::ProcInvoker
+                          .new(subject, record, args)
+                          .with_failures(failures)
+      end
+
+      def class_invoker
+        @class_invoker ||= Invokers::ClassInvoker
+                           .new(subject, record, args)
+                           .with_failures(failures)
+      end
+
+      def literal_invoker
+        @literal_invoker ||= Invokers::LiteralInvoker
+                             .new(subject, record, args)
+                             .with_failures(failures)
+      end
+    end
+  end
+end
diff --git a/lib/aasm/core/invokers/base_invoker.rb b/lib/aasm/core/invokers/base_invoker.rb
@@ -0,0 +1,75 @@
+# frozen_string_literal: true
+
+module AASM
+  module Core
+    module Invokers
+      ##
+      # Base concrete invoker class which contain basic
+      # invoking and logging definitions
+      class BaseInvoker
+        attr_reader :failures, :subject, :record, :args, :result
+
+        ##
+        # Initialize a new concrete invoker instance.
+        # NOTE that concrete invoker must be used per-subject/record
+        #      (one instance per subject/record)
+        #
+        # ==Options:
+        #
+        # +subject+ - invoking subject comparable with this invoker
+        # +record+  - invoking record
+        # +args+    - arguments which will be passed to the callback
+
+        def initialize(subject, record, args)
+          @subject = subject
+          @record = record
+          @args = args
+          @result = false
+          @failures = []
+        end
+
+        ##
+        # Collect failures to a specified buffer
+        #
+        # ==Options:
+        #
+        # +failures+ - failures buffer to collect failures
+
+        def with_failures(failures_buffer)
+          @failures = failures_buffer
+          self
+        end
+
+        ##
+        # Execute concrete invoker, log the error and return result
+
+        def invoke
+          return unless may_invoke?
+          log_failure unless invoke_subject
+          result
+        end
+
+        ##
+        # Check if concrete invoker may be invoked for a specified subject
+
+        def may_invoke?
+          raise NoMethodError, '"#may_invoke?" is not implemented'
+        end
+
+        ##
+        # Log failed invoking
+
+        def log_failure
+          raise NoMethodError, '"#log_failure" is not implemented'
+        end
+
+        ##
+        # Execute concrete invoker
+
+        def invoke_subject
+          raise NoMethodError, '"#invoke_subject" is not implemented'
+        end
+      end
+    end
+  end
+end
diff --git a/lib/aasm/core/invokers/class_invoker.rb b/lib/aasm/core/invokers/class_invoker.rb
@@ -0,0 +1,52 @@
+# frozen_string_literal: true
+
+module AASM
+  module Core
+    module Invokers
+      ##
+      # Class invoker which allows to use classes which respond to #call
+      # to be used as state/event/transition callbacks.
+      class ClassInvoker < BaseInvoker
+        def may_invoke?
+          subject.is_a?(Class) && subject.instance_methods.include?(:call)
+        end
+
+        def log_failure
+          return log_source_location if Method.method_defined?(:source_location)
+          log_method_info
+        end
+
+        def invoke_subject
+          @result = retrieve_instance.call
+        end
+
+        private
+
+        def log_source_location
+          failures << instance.method(:call).source_location.join('#')
+        end
+
+        def log_method_info
+          failures << instance.method(:call)
+        end
+
+        def instance
+          @instance ||= retrieve_instance
+        end
+
+        # rubocop:disable Metrics/AbcSize
+        def retrieve_instance
+          return subject.new if subject_arity.zero?
+          return subject.new(record) if subject_arity == 1
+          return subject.new(record, *args) if subject_arity < 0
+          subject.new(record, *args[0..(subject_arity - 2)])
+        end
+        # rubocop:enable Metrics/AbcSize
+
+        def subject_arity
+          @arity ||= subject.instance_method(:initialize).arity
+        end
+      end
+    end
+  end
+end
diff --git a/lib/aasm/core/invokers/literal_invoker.rb b/lib/aasm/core/invokers/literal_invoker.rb
@@ -0,0 +1,47 @@
+# frozen_string_literal: true
+
+module AASM
+  module Core
+    module Invokers
+      ##
+      # Literal invoker which allows to use strings or symbols to call
+      # record methods as state/event/transition callbacks.
+      class LiteralInvoker < BaseInvoker
+        def may_invoke?
+          subject.is_a?(String) || subject.is_a?(Symbol)
+        end
+
+        def log_failure
+          failures << subject
+        end
+
+        def invoke_subject
+          @result = exec_subject
+        end
+
+        private
+
+        def subject_arity
+          @arity ||= record.__send__(:method, subject.to_sym).arity
+        end
+
+        # rubocop:disable Metrics/AbcSize
+        def exec_subject
+          raise(*record_error) unless record.respond_to?(subject, true)
+          return record.__send__(subject) if subject_arity.zero?
+          return record.__send__(subject, *args) if subject_arity < 0
+          record.__send__(subject, *args[0..(subject_arity - 1)])
+        end
+        # rubocop:enable Metrics/AbcSize
+
+        def record_error
+          [
+            NoMethodError,
+            'NoMethodError: undefined method ' \
+            "`#{subject}' for #{record.inspect}:#{record.class}"
+          ]
+        end
+      end
+    end
+  end
+end