Made some adjustments to toString formatting of...

Made some adjustments to toString formatting of JSON

Closes #3605

Hopefully this is the last time I have to close this ticket. In addition
to default behavior, the end user can specify their own JSON value
formatting function if they want to customize it.

1 files changed, 72 insertions, 4 deletions

diff --git a/src/library/scala/util/parsing/json/Parser.scala b/src/library/scala/util/parsing/json/Parser.scala
index ce9c1dd3fe..b7c338b3be 100644
--- a/src/library/scala/util/parsing/json/Parser.scala
+++ b/src/library/scala/util/parsing/json/Parser.scala
@@ -19,14 +19,81 @@ import scala.util.parsing.combinator.lexical._
  *
  *  @author Derek Chen-Becker <"java"+@+"chen-becker"+"."+"org">
  */
-sealed abstract class JSONType
+sealed abstract class JSONType {
+  /**
+   * This version of toString allows you to provide your own value
+   * formatter.
+   */
+  def toString (formatter : JSONFormat.ValueFormatter) : String
+
+  /**
+   * Returns a String representation of this JSON value
+   * using the JSONFormat.defaultFormatter.
+   */
+  override def toString = toString(JSONFormat.defaultFormatter)
+}
+
+/**
+ * This object defines functions that are used when converting JSONType
+ * values into String representations. Mostly this is concerned with
+ * proper quoting of strings.
+ *
+ * @author Derek Chen-Becker <"java"+@+"chen-becker"+"."+"org">
+ */
+object JSONFormat {
+  /**
+   * This type defines a function that can be used to
+   * format values into JSON format.
+   */
+  type ValueFormatter = Any => String
+
+  /**
+   * The default formatter used by the library. You can
+   * provide your own with the toString calls on
+   * JSONObject and JSONArray instances.
+   */
+  val defaultFormatter : ValueFormatter = (x : Any) => x match {
+    case s : String => "\"" + quoteString(s) + "\""
+    case jo : JSONObject => jo.toString(defaultFormatter)
+    case ja : JSONArray => ja.toString(defaultFormatter)
+    case other => other.toString
+  }
+
+  /**
+   * This function can be used to properly quote Strings
+   * for JSON output.
+   */
+  def quoteString (s : String) : String =
+    s.map {
+      case '"'  => "\\\""
+      case '\\' => "\\\\"
+      case '/'  => "\\/"
+      case '\b' => "\\b"
+      case '\f' => "\\f"
+      case '\n' => "\\n"
+      case '\r' => "\\r"
+      case '\t' => "\\t"
+      /* We'll unicode escape any control characters. These include:
+       * 0x0 -> 0x1f  : ASCII Control (C0 Control Codes)
+       * 0x7f         : ASCII DELETE
+       * 0x80 -> 0x9f : C1 Control Codes
+       *
+       * Per RFC4627, section 2.5, we're not technically required to
+       * encode the C1 codes, but we do to be safe.
+       */
+      case c if ((c >= '\u0000' && c <= '\u001f') || (c >= '\u007f' && c <= '\u009f')) => "\\u%04x".format(c: Int)
+      case c => c
+    }.mkString
+}
 
 /**
  *  Represents a JSON Object (map).
+ *
  *  @author Derek Chen-Becker <"java"+@+"chen-becker"+"."+"org">
  */
-case class JSONObject (obj : Map[Any,Any]) extends JSONType {
-  override def toString = "{" + obj.map({ case (k,v) => k + " : " + v }).mkString(", ") + "}"
+case class JSONObject (obj : Map[String,Any]) extends JSONType {
+  def toString (formatter : JSONFormat.ValueFormatter) =
+    "{" + obj.map({ case (k,v) => formatter(k.toString) + " : " + formatter(v) }).mkString(", ") + "}"
 }
 
 /**
@@ -34,7 +101,8 @@ case class JSONObject (obj : Map[Any,Any]) extends JSONType {
  *  @author Derek Chen-Becker <"java"+@+"chen-becker"+"."+"org">
  */
 case class JSONArray (list : List[Any]) extends JSONType {
-  override def toString = "[" + list.mkString(", ") + "]"
+  def toString (formatter : JSONFormat.ValueFormatter) =
+    "[" + list.map(formatter).mkString(", ") + "]"
 }
 
 /**