Add Packet::create_or_throw.

lib/openpgp/packet.cpp

@@ -1,14 +1,78 @@
-// OpenPGP format
-// Copyright 2017 The NeoPG developers
+// OpenPGP packet (implementation)
+// Copyright 2017-2018 The NeoPG developers
 //
 // NeoPG is released under the Simplified BSD License (see license.txt)
 
 #include <neopg/packet.h>
 
+#include <neopg/marker_packet.h>
+#include <neopg/public_key_packet.h>
+#include <neopg/public_subkey_packet.h>
+#include <neopg/raw_packet.h>
+#include <neopg/signature_packet.h>
+#include <neopg/user_id_packet.h>
+
+#include <neopg/parser_input.h>
 #include <neopg/stream.h>
 
+#include <assert.h>
+#include <neopg/intern/cplusplus.h>
+
+#ifndef NDEBUG
+#include <botan/hex.h>
+#include <sstream>
+#endif
+
 using namespace NeoPG;
 
+std::unique_ptr<Packet> Packet::create_or_throw(PacketType type,
+                                                ParserInput& in) {
+  std::unique_ptr<Packet> packet;
+#ifndef NDEBUG
+  std::string orig_data{in.current(), in.size()};
+#endif
+
+  switch (type) {
+    case PacketType::Marker:
+      packet = MarkerPacket::create_or_throw(in);
+      break;
+    case PacketType::UserId:
+      packet = UserIdPacket::create_or_throw(in);
+      break;
+    case PacketType::PublicKey:
+      packet = PublicKeyPacket::create_or_throw(in);
+      break;
+    case PacketType::PublicSubkey:
+      packet = PublicSubkeyPacket::create_or_throw(in);
+      break;
+    case PacketType::Signature:
+      packet = SignaturePacket::create_or_throw(in);
+      break;
+    default:
+      // Should we do this?
+      packet = NeoPG::make_unique<RawPacket>(
+          type, std::string(in.current(), in.size()));
+      break;
+  }
+
+#ifndef NDEBUG
+  /// Output the packet data and verify that it outputs to
+  /// exactly the same bytes as the original data.
+  std::stringstream out;
+  packet->write_body(out);
+  std::cout << "ORIG: "
+            << Botan::hex_encode((const uint8_t*)orig_data.data(),
+                                 orig_data.size())
+            << "\n";
+  std::string o = out.str();
+  std::cout << "PARS: " << Botan::hex_encode((const uint8_t*)o.data(), o.size())
+            << "\n";
+
+  assert(orig_data == out.str());
+#endif
+  return packet;
+}
+
 void Packet::write(std::ostream& out,
                    packet_header_factory header_factory) const {
   if (m_header) {

lib/openpgp/packet.h

@@ -1,11 +1,12 @@
-// OpenPGP format
-// Copyright 2017 The NeoPG developers
+// OpenPGP packet
+// Copyright 2017-2018 The NeoPG developers
 //
 // NeoPG is released under the Simplified BSD License (see license.txt)
 
 #pragma once
 
 #include <neopg/packet_header.h>
+#include <neopg/parser_input.h>
 
 #include <functional>
 #include <memory>
@@ -16,7 +17,12 @@ using packet_header_factory = std::function<std::unique_ptr<PacketHeader>(
     PacketType type, uint32_t length)>;
 
 struct NEOPG_UNSTABLE_API Packet {
+  static std::unique_ptr<Packet> create_or_throw(PacketType type,
+                                                 ParserInput& in);
+
   /// Use this to overwrite the default header.
+  // FIXME: Replace this with a header-generator that comes in different
+  // flavors, see issue #66.
   std::unique_ptr<PacketHeader> m_header;
 
   /// Write the packet to \p out. If \p m_header is set, use that. Otherwise,