1 files changed, 100 insertions, 15 deletions

diff --git a/activesupport/lib/active_support/notifications/fanout.rb b/activesupport/lib/active_support/notifications/fanout.rb
index 25aab175b4..c506b35b1e 100644
--- a/activesupport/lib/active_support/notifications/fanout.rb
+++ b/activesupport/lib/active_support/notifications/fanout.rb
@@ -2,6 +2,7 @@
 
 require "mutex_m"
 require "concurrent/map"
+require "set"
 
 module ActiveSupport
   module Notifications
@@ -13,16 +14,22 @@ module ActiveSupport
       include Mutex_m
 
       def initialize
-        @subscribers = []
+        @string_subscribers = Hash.new { |h, k| h[k] = [] }
+        @other_subscribers = []
         @listeners_for = Concurrent::Map.new
         super
       end
 
-      def subscribe(pattern = nil, block = Proc.new)
-        subscriber = Subscribers.new pattern, block
+      def subscribe(pattern = nil, callable = nil, &block)
+        subscriber = Subscribers.new(pattern, callable || block)
         synchronize do
-          @subscribers << subscriber
-          @listeners_for.clear
+          if String === pattern
+            @string_subscribers[pattern] << subscriber
+            @listeners_for.delete(pattern)
+          else
+            @other_subscribers << subscriber
+            @listeners_for.clear
+          end
         end
         subscriber
       end
@@ -31,12 +38,19 @@ module ActiveSupport
         synchronize do
           case subscriber_or_name
           when String
-            @subscribers.reject! { |s| s.matches?(subscriber_or_name) }
+            @string_subscribers[subscriber_or_name].clear
+            @listeners_for.delete(subscriber_or_name)
+            @other_subscribers.each { |sub| sub.unsubscribe!(subscriber_or_name) }
           else
-            @subscribers.delete(subscriber_or_name)
+            pattern = subscriber_or_name.try(:pattern)
+            if String === pattern
+              @string_subscribers[pattern].delete(subscriber_or_name)
+              @listeners_for.delete(pattern)
+            else
+              @other_subscribers.delete(subscriber_or_name)
+              @listeners_for.clear
+            end
           end
-
-          @listeners_for.clear
         end
       end
 
@@ -56,7 +70,8 @@ module ActiveSupport
         # this is correctly done double-checked locking (Concurrent::Map's lookups have volatile semantics)
         @listeners_for[name] || synchronize do
           # use synchronisation when accessing @subscribers
-          @listeners_for[name] ||= @subscribers.select { |s| s.subscribed_to?(name) }
+          @listeners_for[name] ||=
+            @string_subscribers[name] + @other_subscribers.select { |s| s.subscribed_to?(name) }
         end
       end
 
@@ -70,12 +85,29 @@ module ActiveSupport
 
       module Subscribers # :nodoc:
         def self.new(pattern, listener)
+          subscriber_class = Timed
+
           if listener.respond_to?(:start) && listener.respond_to?(:finish)
-            subscriber = Evented.new pattern, listener
+            subscriber_class = Evented
           else
-            subscriber = Timed.new pattern, listener
+            # Doing all this to detect a block like `proc { |x| }` vs
+            # `proc { |*x| }` or `proc { |**x| }`
+            if listener.respond_to?(:parameters)
+              params = listener.parameters
+              if params.length == 1 && params.first.first == :opt
+                subscriber_class = EventObject
+              end
+            end
           end
 
+          wrap_all pattern, subscriber_class.new(pattern, listener)
+        end
+
+        def self.event_object_subscriber(pattern, block)
+          wrap_all pattern, EventObject.new(pattern, block)
+        end
+
+        def self.wrap_all(pattern, subscriber)
           unless pattern
             AllMessages.new(subscriber)
           else
@@ -83,9 +115,33 @@ module ActiveSupport
           end
         end
 
+        class Matcher #:nodoc:
+          attr_reader :pattern, :exclusions
+
+          def self.wrap(pattern)
+            return pattern if String === pattern
+            new(pattern)
+          end
+
+          def initialize(pattern)
+            @pattern = pattern
+            @exclusions = Set.new
+          end
+
+          def unsubscribe!(name)
+            exclusions << -name if pattern === name
+          end
+
+          def ===(name)
+            pattern === name && !exclusions.include?(name)
+          end
+        end
+
         class Evented #:nodoc:
+          attr_reader :pattern
+
           def initialize(pattern, delegate)
-            @pattern = pattern
+            @pattern = Matcher.wrap(pattern)
             @delegate = delegate
             @can_publish = delegate.respond_to?(:publish)
           end
@@ -105,11 +161,15 @@ module ActiveSupport
           end
 
           def subscribed_to?(name)
-            @pattern === name
+            pattern === name
           end
 
           def matches?(name)
-            @pattern && @pattern === name
+            pattern && pattern === name
+          end
+
+          def unsubscribe!(name)
+            pattern.unsubscribe!(name)
           end
         end
 
@@ -130,6 +190,27 @@ module ActiveSupport
           end
         end
 
+        class EventObject < Evented
+          def start(name, id, payload)
+            stack = Thread.current[:_event_stack] ||= []
+            event = build_event name, id, payload
+            event.start!
+            stack.push event
+          end
+
+          def finish(name, id, payload)
+            stack = Thread.current[:_event_stack]
+            event = stack.pop
+            event.finish!
+            @delegate.call event
+          end
+
+          private
+            def build_event(name, id, payload)
+              ActiveSupport::Notifications::Event.new name, nil, nil, id, payload
+            end
+        end
+
         class AllMessages # :nodoc:
           def initialize(delegate)
             @delegate = delegate
@@ -151,6 +232,10 @@ module ActiveSupport
             true
           end
 
+          def unsubscribe!(*)
+            false
+          end
+
           alias :matches? :===
         end
       end