Adding in loading thread local behaviour

lib/mongoid/threaded.rb

@@ -56,6 +56,18 @@ def begin_create
       create_stack.push(true)
     end
 
+    # Begins a creating block.
+    #
+    # @example Begin the load.
+    #   Threaded.begin_load
+    #
+    # @return [ true ] Always true.
+    #
+    # @since 2.3.2
+    def begin_load
+      load_stack.push(true)
+    end
+
     # Begin validating a document on the current thread.
     #
     # @example Begin validation.
@@ -116,6 +128,18 @@ def creating?
       !create_stack.empty?
     end
 
+    # Is the current thread in creating mode?
+    #
+    # @example Is the thread in creating mode?
+    #   Threaded.creating?
+    #
+    # @return [ true, false ] If the thread is in creating mode?
+    #
+    # @since 2.3.2
+    def loading?
+      !load_stack.empty?
+    end
+
     # Get the assign stack for the current thread. Is simply an array of calls
     # to Mongoid's assigning method.
     #
@@ -168,6 +192,19 @@ def create_stack
       Thread.current[:"[mongoid]:create-stack"] ||= []
     end
 
+    # Get the load stack for the current thread. Is simply an array of calls
+    # to Mongoid's loading method.
+    #
+    # @example Get the load stack.
+    #   Threaded.load_stack
+    #
+    # @return [ Array ] The array of load calls.
+    #
+    # @since 2.3.2
+    def load_stack
+      Thread.current[:"[mongoid]:load-stack"] ||= []
+    end
+
     # Clear out all the safety options set using the safely proxy.
     #
     # @example Clear out the options.
@@ -239,6 +276,18 @@ def exit_create
       create_stack.pop
     end
 
+    # Exit the loading block.
+    #
+    # @example Exit the loading block.
+    #   Threaded.exit_load
+    #
+    # @return [ true ] The last element in the stack.
+    #
+    # @since 2.1.9
+    def exit_load
+      load_stack.pop
+    end
+
     # Exit validating a document on the current thread.
     #
     # @example Exit validation.

lib/mongoid/threaded/lifecycle.rb

@@ -110,6 +110,35 @@ def _creating?
         Threaded.creating?
       end
 
+      # Execute a block in loading mode.
+      #
+      # @example Execute in loading mode.
+      #   _loading do
+      #     relation.push(doc)
+      #   end
+      #
+      # @return [ Object ] The return value of the block.
+      #
+      # @since 2.3.2
+      def _loading
+        Threaded.begin_build
+        yield
+      ensure
+        Threaded.exit_build
+      end
+
+      # Is the current thread in loading mode?
+      #
+      # @example Is the current thread in loading mode?
+      #   proxy._loading?
+      #
+      # @return [ true, false ] If the thread is loading.
+      #
+      # @since 2.3.2
+      def _loading?
+        Threaded.loading?
+      end
+
       module ClassMethods #:nodoc:
 
         # Execute a block in creating mode.

spec/unit/mongoid/threaded_spec.rb

@@ -6,6 +6,90 @@
     stub
   end
 
+  describe "#begin_load" do
+
+    before do
+      described_class.begin_load
+    end
+
+    after do
+      described_class.load_stack.clear
+    end
+
+    it "adds a boolen to the load stack" do
+      described_class.load_stack.should eq([ true ])
+    end
+  end
+
+  describe "#loading?" do
+
+    context "when loading is not set" do
+
+      it "returns false" do
+        described_class.should_not be_loading
+      end
+    end
+
+    context "when loading has elements" do
+
+      before do
+        Thread.current[:"[mongoid]:load-stack"] = [ true ]
+      end
+
+      after do
+        Thread.current[:"[mongoid]:load-stack"] = []
+      end
+
+      it "returns true" do
+        described_class.should be_loading
+      end
+    end
+
+    context "when loading has no elements" do
+
+      before do
+        Thread.current[:"[mongoid]:load-stack"] = []
+      end
+
+      it "returns false" do
+        described_class.should_not be_loading
+      end
+    end
+  end
+
+  describe "#load_stack" do
+
+    context "when no load stack has been initialized" do
+
+      let(:loading) do
+        described_class.load_stack
+      end
+
+      it "returns an empty stack" do
+        loading.should eq([])
+      end
+    end
+
+    context "when a load stack has been initialized" do
+
+      before do
+        Thread.current[:"[mongoid]:load-stack"] = [ true ]
+      end
+
+      let(:loading) do
+        described_class.load_stack
+      end
+
+      after do
+        Thread.current[:"[mongoid]:load-stack"] = []
+      end
+
+      it "returns the stack" do
+        loading.should eq([ true ])
+      end
+    end
+  end
+
   describe "#begin_assign" do
 
     before do
@@ -370,6 +454,22 @@
     end
   end
 
+  describe "#exit_load" do
+
+    before do
+      described_class.begin_load
+      described_class.exit_load
+    end
+
+    after do
+      described_class.load_stack.clear
+    end
+
+    it "adds a boolen to the load stack" do
+      described_class.load_stack.should be_empty
+    end
+  end
+
   describe "#exit_bind" do
 
     before do