* ext/psych/lib/psych/json/stream.rb: adding a JSON streaming API

* ext/psych/lib/psych/stream.rb: ditto
* ext/psych/lib/psych.rb: using autoload
* ext/psych/lib/psych/json.rb: ditto
* ext/psych/lib/psych/json/tree_builder.rb: refactor
* ext/psych/lib/psych/visitors/json_tree.rb: refactor

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@27961 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

2 files changed, 42 insertions, 2 deletions

diff --git a/ext/psych/lib/psych/json/stream.rb b/ext/psych/lib/psych/json/stream.rb
new file mode 100644
index 0000000000..a6da584cbf
--- /dev/null
+++ b/ext/psych/lib/psych/json/stream.rb
@@ -0,0 +1,32 @@
+module Psych
+  module JSON
+    class Stream < Psych::Stream
+      class Emitter < Psych::Stream::Emitter # :nodoc:
+        def start_document version, tag_directives, implicit
+          super(version, tag_directives, !streaming?)
+        end
+
+        def start_mapping anchor, tag, implicit, style
+          super(anchor, tag, implicit, Nodes::Mapping::FLOW)
+        end
+
+        def start_sequence anchor, tag, implicit, style
+          super(anchor, tag, implicit, Nodes::Sequence::FLOW)
+        end
+
+        def scalar value, anchor, tag, plain, quoted, style
+          if "tag:yaml.org,2002:null" == tag
+            super('null', nil, nil, true, false, Nodes::Scalar::PLAIN)
+          else
+            super
+          end
+        end
+      end
+
+      def visit_String o
+        @emitter.scalar o.to_s, nil, nil, false, true, Nodes::Scalar::ANY
+      end
+      alias :visit_Symbol :visit_String
+    end
+  end
+end
diff --git a/ext/psych/lib/psych/json/tree_builder.rb b/ext/psych/lib/psych/json/tree_builder.rb
index d0a76177bf..720ede7e1e 100644
--- a/ext/psych/lib/psych/json/tree_builder.rb
+++ b/ext/psych/lib/psych/json/tree_builder.rb
@@ -5,11 +5,11 @@ module Psych
     # to an instance of Psych::JSON::TreeBuilder and a JSON AST is constructed.
     class TreeBuilder < Psych::TreeBuilder
       def start_document version, tag_directives, implicit
-        super(version, tag_directives, true)
+        super(version, tag_directives, !streaming?)
       end
 
       def end_document implicit_end = !streaming?
-        super(true)
+        super(implicit_end)
       end
 
       def start_mapping anchor, tag, implicit, style
@@ -19,6 +19,14 @@ module Psych
       def start_sequence anchor, tag, implicit, style
         super(anchor, tag, implicit, Nodes::Sequence::FLOW)
       end
+
+      def scalar value, anchor, tag, plain, quoted, style
+        if "tag:yaml.org,2002:null" == tag
+          super('null', nil, nil, true, false, Nodes::Scalar::PLAIN)
+        else
+          super
+        end
+      end
     end
   end
 end