Backported #84 implementation to 2.9

Author: cowtowncoder

release-notes/CREDITS-2.x

@@ -21,3 +21,8 @@ Fabrice Delhoste (spifd@github)
 * Reported #74 (properties): `JavaPropsMapper` issue deserializing multiple byte array properties
  (2.9.5)
 
+Thomas Hauk (thauk-copperleaf@github)
+
+* Contibuted #84 (yaml): Add option to allow use of platform-linefeed
+  (`YAMLGenerator.Feature.USE_PLATFORM_LINE_BREAKS`)
+ (2.9.6)

release-notes/VERSION-2.x

@@ -8,6 +8,12 @@ Modules:
 === Releases ===
 ------------------------------------------------------------------------
 
+2.9.6 (not yet released)
+
+#84 (yaml): Add option to allow use of platform-linefeed
+  (`YAMLGenerator.Feature.USE_PLATFORM_LINE_BREAKS`)
+ (contributed by Thomas H)
+
 2.9.5 (26-Mar-2018)
 
 #74 (properties): `JavaPropsMapper` issue deserializing multiple byte array properties

yaml/src/main/java/com/fasterxml/jackson/dataformat/yaml/YAMLGenerator.java

@@ -113,7 +113,18 @@ public enum Feature implements FormatFeature // since 2.9
          *
          * @since 2.9
          */
-        INDENT_ARRAYS(false)
+        INDENT_ARRAYS(false),
+
+        /**
+         * Option passed to SnakeYAML that determines if the line breaks used for
+         * serialization should be same as what the default is for current platform.
+         * If disabled, Unix linefeed ({@code \n}) will be used.
+         * <p>
+         * Default value is `false` for backwards compatibility.
+         *
+         * @since 2.9.6
+         */
+        USE_PLATFORM_LINE_BREAKS(false),
         ;
 
         protected final boolean _defaultState;
@@ -266,6 +277,10 @@ protected DumperOptions buildDumperOptions(int jsonFeatures, int yamlFeatures,
             opt.setIndicatorIndent(1);
             opt.setIndent(2);
         }
+        // 14-May-2018: [dataformats-text#84] allow use of platform linefeed
+        if (Feature.USE_PLATFORM_LINE_BREAKS.enabledIn(_formatFeatures)) {
+            opt.setLineBreak(DumperOptions.LineBreak.getPlatformLineBreak());
+        }
         return opt;
     }
 

yaml/src/test/java/com/fasterxml/jackson/dataformat/yaml/ser/GeneratorFeatureTest.java

@@ -7,7 +7,6 @@
 import com.fasterxml.jackson.dataformat.yaml.ModuleTestBase;
 import com.fasterxml.jackson.dataformat.yaml.YAMLGenerator;
 import com.fasterxml.jackson.dataformat.yaml.YAMLMapper;
-import com.fasterxml.jackson.dataformat.yaml.YAMLGenerator.Feature;
 
 public class GeneratorFeatureTest extends ModuleTestBase
 {