Apply some lipstick to llarp_buffer_t

This class is cursed, but also broken under gcc-12.  Apply some lipstick
to get it moving again (but we really need to refactor this because it
is a mess).

llarp/CMakeLists.txt

@@ -117,7 +117,6 @@ target_link_libraries(lokinet-config PUBLIC lokinet-dns lokinet-platform oxenmq:
 
 add_library(lokinet-amalgum
   STATIC
-  consensus/table.cpp
   consensus/reachability_testing.cpp
 
   bootstrap.cpp

llarp/consensus/table.cpp

@@ -1,17 +0,0 @@
-#include "table.hpp"
-#include <llarp/crypto/crypto.hpp>
-
-namespace llarp
-{
-  namespace consensus
-  {
-    ShortHash
-    Table::CalculateHash() const
-    {
-      ShortHash h;
-      const llarp_buffer_t buf(begin()->data(), size());
-      CryptoManager::instance()->shorthash(h, buf);
-      return h;
-    }
-  }  // namespace consensus
-}  // namespace llarp

llarp/consensus/table.hpp

@@ -1,17 +0,0 @@
-#pragma once
-
-#include <llarp/crypto/types.hpp>
-#include <vector>
-
-namespace llarp
-{
-  namespace consensus
-  {
-    /// consensus table
-    struct Table : public std::vector<RouterID>
-    {
-      ShortHash
-      CalculateHash() const;
-    };
-  }  // namespace consensus
-}  // namespace llarp

llarp/exit/session.cpp

@@ -243,7 +243,7 @@ namespace llarp
       {
         queue.emplace_back();
         queue.back().protocol = t;
-        return queue.back().PutBuffer(std::move(pkt), m_Counter++);
+        return queue.back().PutBuffer(llarp_buffer_t{pkt}, m_Counter++);
       }
       auto& back = queue.back();
       // pack to nearest N
@@ -251,10 +251,10 @@ namespace llarp
       {
         queue.emplace_back();
         queue.back().protocol = t;
-        return queue.back().PutBuffer(std::move(pkt), m_Counter++);
+        return queue.back().PutBuffer(llarp_buffer_t{pkt}, m_Counter++);
       }
       back.protocol = t;
-      return back.PutBuffer(std::move(pkt), m_Counter++);
+      return back.PutBuffer(llarp_buffer_t{pkt}, m_Counter++);
     }
 
     bool

llarp/quic/endpoint.cpp

@@ -185,7 +185,8 @@ namespace llarp::quic
     std::memcpy(&buf_[header_size], data.data(), data.size());
     bstring_view outgoing{buf_.data(), outgoing_len};
 
-    if (service_endpoint.SendToOrQueue(to, outgoing, service::ProtocolType::QUIC))
+    if (service_endpoint.SendToOrQueue(
+            to, llarp_buffer_t{outgoing.data(), outgoing.size()}, service::ProtocolType::QUIC))
     {
       LogTrace("[", to, "]: sent ", buffer_printer{outgoing});
     }

llarp/service/outbound_context.cpp

@@ -334,9 +334,10 @@ namespace llarp
     void
     OutboundContext::KeepAlive()
     {
-      Encrypted<64> tmp;
-      tmp.Randomize();
-      SendPacketToRemote(tmp, ProtocolType::Control);
+      std::array<byte_t, 64> tmp;
+      llarp_buffer_t buf{tmp};
+      CryptoManager::instance()->randomize(buf);
+      SendPacketToRemote(buf, ProtocolType::Control);
       m_LastKeepAliveAt = Now();
     }
 

llarp/util/buffer.cpp

@@ -127,12 +127,6 @@ llarp_buffer_t::copy() const
   return copy;
 }
 
-bool
-operator==(const llarp_buffer_t& buff, std::string_view data)
-{
-  return std::string_view{reinterpret_cast<const char*>(buff.cur), buff.size_left()} == data;
-}
-
 llarp::byte_view_t
 llarp_buffer_t::view() const
 {

llarp/util/buffer.hpp

@@ -22,6 +22,8 @@ namespace llarp
   using byte_view_t = std::basic_string_view<byte_t>;
 }
 
+struct ManagedBuffer;
+
 /// TODO: replace usage of these with std::span (via a backport until we move to C++20).  That's a
 /// fairly big job, though, as llarp_buffer_t is currently used a bit differently (i.e. maintains
 /// both start and current position, plus has some value reading/writing methods).
@@ -44,29 +46,65 @@ struct [[deprecated("this type is stupid, use something else")]] llarp_buffer_t
   llarp_buffer_t(byte_t * b, byte_t * c, size_t s) : base(b), cur(c), sz(s)
   {}
 
+  llarp_buffer_t(const ManagedBuffer&) = delete;
+  llarp_buffer_t(ManagedBuffer &&) = delete;
+
+  template <typename Byte>
+  static constexpr bool is_basic_byte = sizeof(Byte) == 1 and std::is_trivially_copyable_v<Byte>;
+
   /// Construct referencing some 1-byte, trivially copyable (e.g. char, unsigned char, byte_t)
   /// pointer type and a buffer size.
   template <
-      typename T,
-      typename = std::enable_if_t<sizeof(T) == 1 and std::is_trivially_copyable_v<T>>>
-  llarp_buffer_t(T * buf, size_t _sz)
-      : base(reinterpret_cast<byte_t*>(const_cast<std::remove_const_t<T>*>(buf)))
-      , cur(base)
-      , sz(_sz)
+      typename Byte,
+      typename = std::enable_if_t<not std::is_const_v<Byte> && is_basic_byte<Byte>>>
+  llarp_buffer_t(Byte * buf, size_t sz) : base{reinterpret_cast<byte_t*>(buf)}, cur{base}, sz{sz}
+  {}
+
+  /// initialize llarp_buffer_t from vector or array of byte-like values
+  template <
+      typename Byte,
+      typename = std::enable_if_t<not std::is_const_v<Byte> && is_basic_byte<Byte>>>
+  llarp_buffer_t(std::vector<Byte> & b) : llarp_buffer_t{b.data(), b.size()}
   {}
 
-  /// initialize llarp_buffer_t from containers supporting .data() and .size()
+  template <
+      typename Byte,
+      size_t N,
+      typename = std::enable_if_t<not std::is_const_v<Byte> && is_basic_byte<Byte>>>
+  llarp_buffer_t(std::array<Byte, N> & b) : llarp_buffer_t{b.data(), b.size()}
+  {}
+
+  // These overloads, const_casting away the const, are not just gross but downright dangerous:
+  template <typename Byte, typename = std::enable_if_t<is_basic_byte<Byte>>>
+  [[deprecated("dangerous constructor that casts away constness, be very careful")]] llarp_buffer_t(
+      const Byte* buf, size_t sz)
+      : llarp_buffer_t{const_cast<Byte*>(buf), sz}
+  {}
+
+  template <typename Byte, typename = std::enable_if_t<is_basic_byte<Byte>>>
+  [[deprecated("dangerous constructor that casts away constness, be very careful")]] llarp_buffer_t(
+      const std::vector<Byte>& b)
+      : llarp_buffer_t{const_cast<Byte*>(b.data()), b.size()}
+  {}
+
+  template <typename Byte, size_t N, typename = std::enable_if_t<is_basic_byte<Byte>>>
+  [[deprecated("dangerous constructor that casts away constness, be very careful")]] llarp_buffer_t(
+      const std::array<Byte, N>& b)
+      : llarp_buffer_t{const_cast<Byte*>(b.data()), b.size()}
+  {}
+
+  /// Explicitly construct a llarp_buffer_t from anything with a `.data()` and a `.size()`.  Cursed.
   template <
       typename T,
       typename = std::void_t<decltype(std::declval<T>().data() + std::declval<T>().size())>>
-  llarp_buffer_t(T && t) : llarp_buffer_t{t.data(), t.size()}
+  explicit llarp_buffer_t(T && t) : llarp_buffer_t{t.data(), t.size()}
   {}
 
   byte_t* begin()
   {
     return base;
   }
-  byte_t* begin() const
+  const byte_t* begin() const
   {
     return base;
   }
@@ -74,7 +112,7 @@ struct [[deprecated("this type is stupid, use something else")]] llarp_buffer_t
   {
     return base + sz;
   }
-  byte_t* end() const
+  const byte_t* end() const
   {
     return base + sz;
   }
@@ -125,10 +163,6 @@ struct [[deprecated("this type is stupid, use something else")]] llarp_buffer_t
   llarp_buffer_t(llarp_buffer_t &&) = default;
 };
 
-
-bool
-operator==(const llarp_buffer_t& buff, std::string_view data);
-
 template <typename OutputIt>
 bool
 llarp_buffer_t::read_into(OutputIt begin, OutputIt end)