// // Copyright (c) 2008, Kevin McIntire // Licensed under the Academic Free License version 3.0 // // History: // 20 Sep 08 Kevin McIntire Creation // 24 Mar 10 Brian Frank json::JsonWriter to util::JsonOutStream // ** ** JsonOutStream writes objects in Javascript Object Notation (JSON). ** ** See [pod doc]`pod-doc#json` for details. ** class JsonOutStream : OutStream { ** ** Convenience for `writeJson` to an in-memory string. ** public static Str writeJsonToStr(Obj? obj) { buf := Buf() // TODO: switch to StrBuf once #1031 is fixed JsonOutStream(buf.out).writeJson(obj) return buf.flip.readAllStr } ** ** Construct by wrapping given output stream. ** new make(OutStream out) : super(out) {} ** ** Write the given object as JSON to this stream. ** The obj must be one of the follow: ** - null ** - Bool ** - Num ** - Str ** - Str:Obj? ** - Obj?[] ** - [simple]`docLang::Serialization#simple` (written as JSON string) ** - [serializable]`docLang::Serialization#serializable` (written as JSON object) ** Void writeJson(Obj? obj) { if (obj is Str) writeJsonStr(obj) else if (obj is Num) writeJsonNum(obj) else if (obj is Bool) writeJsonBool(obj) else if (obj is Map) writeJsonMap(obj) else if (obj is List) writeJsonList(obj) else if (obj == null) writeJsonNull else writeJsonObj(obj) } private Void writeJsonObj(Obj obj) { type := Type.of(obj) // if a simple, write it as a string ser := type.facet(Serializable#, false) as Serializable if (ser == null) throw IOErr("Object type not serializable: $type") if (ser.simple) { writeJsonStr(obj.toStr) return } // serialize as JSON object writeChar(JsonToken.objectStart) type.fields.each |f, i| { if (i != 0) writeChar(JsonToken.comma).writeChar('\n') if (f.isStatic || f.hasFacet(Transient#) == true) return writeJsonPair(f.name, f.get(obj)) } writeChar(JsonToken.objectEnd) } private Void writeJsonMap(Str:Obj? map) { writeChar(JsonToken.objectStart) notFirst := false map.each |val, key| { if (notFirst) writeChar(JsonToken.comma).writeChar('\n') writeJsonPair(key, val) notFirst = true } writeChar(JsonToken.objectEnd) } private Void writeJsonList(Obj?[] array) { writeChar(JsonToken.arrayStart) notFirst := false array.each |item| { if (notFirst) writeChar(JsonToken.comma) writeJson(item) notFirst = true } writeChar(JsonToken.arrayEnd) } private Void writeJsonStr(Str str) { writeChar(JsonToken.quote) str.each |char| { if (char <= 0x7f) { switch (char) { case '\b': writeChar('\\').writeChar('b') case '\f': writeChar('\\').writeChar('f') case '\n': writeChar('\\').writeChar('n') case '\r': writeChar('\\').writeChar('r') case '\t': writeChar('\\').writeChar('t') case '\\': writeChar('\\').writeChar('\\') case '"': writeChar('\\').writeChar('"') default: writeChar(char) } } else { writeChar('\\').writeChar('u').print(char.toHex(4)) } } writeChar(JsonToken.quote) } private Void writeJsonNum(Num num) { print(num) } private Void writeJsonBool(Bool bool) { print(bool) } private Void writeJsonNull() { print("null") } private Void writeJsonPair(Str key, Obj? val) { writeJsonStr(key) writeChar(JsonToken.colon) writeJson(val) } }