commit ae3c7a7aabfb345968a65001ea9bc25f1e2bb405
author Aaron Jacobs <aaronjjacobs@gmail.com> Mon Mar 12 04:53:57 2012 +0000
committer Aaron Jacobs <aaronjjacobs@gmail.com> Mon Mar 12 04:53:57 2012 +0000
tree 6b6a14a9262e28ba27b757d9105f8119700c3651
parent f572e8e42e22cfcf5ab0aea26574f408943edfa4

Made it possible to drop null placeholders from array output.

This can be used when it's clear that the consumer is able to deal with
this, as web browsers are. Thanks to Yatin Chawathe for the patch.

include/json/writer.h

diff --git a/include/json/writer.h b/include/json/writer.h
index 38d41e1..46d5ccc 100644
--- a/include/json/writer.h
+++ b/include/json/writer.h
@@ -40,6 +40,13 @@
 
       void enableYAMLCompatibility();
 
+      /** \brief Drop the "null" string from the writer's output for nullValues.
+       * Strictly speaking, this is not valid JSON. But when the output is being
+       * fed to a browser's Javascript, it makes for smaller output and the
+       * browser can handle the output just fine.
+       */
+      void dropNullPlaceholders();
+
    public: // overridden from Writer
       virtual std::string write( const Value &root );
 
@@ -48,6 +55,7 @@
 
       std::string document_;
       bool yamlCompatiblityEnabled_;
+      bool dropNullPlaceholders_;
    };
 
    /** \brief Writes a Value in <a HREF="http://www.json.org">JSON</a> format in a human friendly way.

src/lib_json/json_writer.cpp

diff --git a/src/lib_json/json_writer.cpp b/src/lib_json/json_writer.cpp
index b44def3..ccf323a 100644
--- a/src/lib_json/json_writer.cpp
+++ b/src/lib_json/json_writer.cpp
@@ -192,7 +192,8 @@
 // //////////////////////////////////////////////////////////////////
 
 FastWriter::FastWriter()
-   : yamlCompatiblityEnabled_( false )
+   : yamlCompatiblityEnabled_( false ),
+     dropNullPlaceholders_( false )
 {
 }
 
@@ -204,6 +205,13 @@
 }
 
 
+void
+FastWriter::dropNullPlaceholders()
+{
+   dropNullPlaceholders_ = true;
+}
+
+
 std::string 
 FastWriter::write( const Value &root )
 {
@@ -220,7 +228,7 @@
    switch ( value.type() )
    {
    case nullValue:
-      document_ += "null";
+      if (!dropNullPlaceholders_) document_ += "null";
       break;
    case intValue:
       document_ += valueToString( value.asLargestInt() );

src/test_lib_json/main.cpp

diff --git a/src/test_lib_json/main.cpp b/src/test_lib_json/main.cpp
index c6ab619..3e28085 100644
--- a/src/test_lib_json/main.cpp
+++ b/src/test_lib_json/main.cpp
@@ -1399,6 +1399,23 @@
     JSONTEST_ASSERT( y.compare( x ) == 0 );
 }
 
+
+struct WriterTest : JsonTest::TestCase
+{
+};
+
+
+JSONTEST_FIXTURE( WriterTest, dropNullPlaceholders )
+{
+    Json::FastWriter writer;
+    Json::Value nullValue;
+    JSONTEST_ASSERT( writer.write(nullValue) == "null\n" );
+
+    writer.dropNullPlaceholders();
+    JSONTEST_ASSERT( writer.write(nullValue) == "\n" );
+}
+
+
 int main( int argc, const char *argv[] )
 {
    JsonTest::Runner runner;
@@ -1420,5 +1437,6 @@
    JSONTEST_REGISTER_FIXTURE( runner, ValueTest, compareArray );
    JSONTEST_REGISTER_FIXTURE( runner, ValueTest, compareObject );
    JSONTEST_REGISTER_FIXTURE( runner, ValueTest, compareType );
+   JSONTEST_REGISTER_FIXTURE( runner, WriterTest, dropNullPlaceholders );
    return runner.runCommandLine( argc, argv );
 }