x509: finish JSON interface with extensions

Complete the certificate fromJSON interface and demonstrate
with a test how to create a new key and self-signed cert. Part
of this commit includes refactoring classes like RDNSequence from
x509 up to ASN1, so the classes can be imported by the extensions
as well. There is an openssl test which can be made optional.

lib/encoding/asn1.js

@@ -597,6 +597,7 @@ class Choice extends Node {
     assert(node instanceof Node);
     this.node = node;
     this.from(...options);
+    this.types = types;
   }
 
   get type() {
@@ -607,6 +608,10 @@ class Choice extends Node {
     throw new Error('Unimplemented.');
   }
 
+  typeToClass(type) {
+    return typeToClass(type);
+  }
+
   getSize(extra) {
     return this.node.getSize(extra);
   }
@@ -634,7 +639,7 @@ class Choice extends Node {
     if (choices.indexOf(hdr.type) === -1)
       throw new Error(`Could not satisfy choice for: ${hdr.type}.`);
 
-    const Node = typeToClass(hdr.type);
+    const Node = this.typeToClass(hdr.type);
     const el = new Node();
     el.flags = this.flags;
 
@@ -680,8 +685,8 @@ class Choice extends Node {
   }
 
   fromJSON(json) {
-    const type = types[json.type.toUpperCase()];
-    const Node = typeToClass(type);
+    const type = this.types[json.type.toUpperCase()];
+    const Node = this.typeToClass(type);
     this.node = new Node();
     this.node.fromJSON(json.node);
     this.node.flags = this.flags;
@@ -2012,6 +2017,223 @@ class GenString extends Str {
   }
 }
 
+/**
+ * RDNSequence
+ */
+
+// Name ::= CHOICE { -- only one possibility for now --
+//      rdnSequence  RDNSequence }
+//
+// RDNSequence ::= SEQUENCE OF RelativeDistinguishedName
+
+class RDNSequence extends Sequence {
+  constructor() {
+    super();
+    this.names = [];
+  }
+
+  getBodySize() {
+    let size = 0;
+
+    for (const rdn of this.names)
+      size += rdn.getSize();
+
+    return size;
+  }
+
+  writeBody(bw) {
+    for (const rdn of this.names)
+      rdn.write(bw);
+    return bw;
+  }
+
+  readBody(br) {
+    while (br.left()) {
+      const rdn = RDN.read(br);
+      this.names.push(rdn);
+    }
+
+    return this;
+  }
+
+  clean() {
+    return this.names.length === 0;
+  }
+
+  format() {
+    return {
+      type: this.constructor.name,
+      names: this.names
+    };
+  }
+
+  getJSON() {
+    const names = [];
+    for (const name of this.names)
+      names.push(name.getJSON());
+
+    return names;
+  }
+
+  fromJSON(json) {
+    assert(Array.isArray(json));
+    for (const name of json)
+      this.names.push(RDN.fromJSON(name));
+
+    return this;
+  }
+}
+
+/**
+ * RDN
+ */
+
+// RelativeDistinguishedName ::=
+//      SET SIZE (1..MAX) OF AttributeTypeAndValue
+//
+
+class RDN extends Set {
+  constructor(id, value) {
+    super();
+    this.attributes = [new Attribute(id, value)];
+  }
+
+  getBodySize() {
+    let size = 0;
+
+    assert(this.attributes.length >= 1);
+
+    for (const attr of this.attributes)
+      size += attr.getSize();
+
+    return size;
+  }
+
+  writeBody(bw) {
+    assert(this.attributes.length >= 1);
+
+    for (const attr of this.attributes)
+      attr.write(bw);
+
+    return bw;
+  }
+
+  readBody(br) {
+    this.attributes[0].read(br);
+
+    while (br.left()) {
+      const attr = Attribute.read(br);
+      this.attributes.push(attr);
+    }
+
+    return this;
+  }
+
+  clean() {
+    return this.attributes.length === 1 && this.attributes[0].clean();
+  }
+
+  format() {
+    return {
+      type: this.constructor.name,
+      attributes: this.attributes
+    };
+  }
+
+  getJSON() {
+    const attributes = [];
+    for (const attr of this.attributes)
+      attributes.push(attr.getJSON());
+
+    return attributes;
+  }
+
+  fromJSON(json) {
+    assert(Array.isArray(json));
+    this.attributes = [];
+
+    for (const attr of json)
+      this.attributes.push(Attribute.fromJSON(attr));
+
+    return this;
+  }
+
+  static fromJSON(json) {
+    return new this().fromJSON(json);
+  }
+}
+
+/**
+ * Attribute
+ */
+
+// AttributeTypeAndValue ::= SEQUENCE {
+//      type     AttributeType,
+//      value    AttributeValue }
+//
+// AttributeType ::= OBJECT IDENTIFIER
+//
+// AttributeValue ::= ANY -- DEFINED BY AttributeType
+
+class Attribute extends Sequence {
+  constructor(id, value) {
+    super();
+
+    this.id = new OID(id);
+    this.value = new Any(value);
+  }
+
+  getBodySize() {
+    let size = 0;
+    size += this.id.getSize();
+    size += this.value.getSize();
+    return size;
+  }
+
+  writeBody(bw) {
+    this.id.write(bw);
+    this.value.write(bw);
+    return bw;
+  }
+
+  readBody(br) {
+    this.id.read(br);
+    this.value.read(br);
+    return this;
+  }
+
+  clean() {
+    return this.id.clean()
+        && this.value.clean();
+  }
+
+  format() {
+    return {
+      type: this.constructor.name,
+      id: this.id,
+      value: this.value
+    };
+  }
+
+  getJSON() {
+    return {
+      id: this.id.getJSON(),
+      value: this.value.getJSON()
+    };
+  }
+
+  fromJSON(json) {
+    this.id.fromJSON(json.id);
+    this.value.fromJSON(json.value);
+
+    return this;
+  }
+
+  static fromJSON(json) {
+    return new this().fromJSON(json);
+  }
+}
+
 /**
  * API
  */
@@ -2615,5 +2837,8 @@ exports.Time = Time;
 exports.UTCTime = UTCTime;
 exports.GenTime = GenTime;
 exports.GenString = GenString;
+exports.RDNSequence = RDNSequence;
+exports.RDN = RDN;
+exports.Attribute = Attribute;
 
 exports.typeToClass = typeToClass;