Add move-friendly buffer accessors

include/libp2p/multi/multihash.hpp

@@ -6,6 +6,7 @@
 
 #pragma once
 
+#include <memory>
 #include <utility>
 
 #include <libp2p/common/types.hpp>
@@ -85,7 +86,13 @@ namespace libp2p::multi {
     /**
      * @return a buffer with the multihash, including its type, length and hash
      */
-    const Buffer &toBuffer() const;
+    const Buffer &toBuffer() const &;
+
+    /**
+     * @return a buffer with the multihash, including its type, length and hash
+     *         (moved out of a temporary when unique)
+     */
+    Buffer toBuffer() &&;
 
     /**
      * @return Pre-calculated hash for std containers
@@ -129,7 +136,7 @@ namespace libp2p::multi {
 
     const Data &data() const;
 
-    std::shared_ptr<const Data> data_;
+    std::shared_ptr<Data> data_;
   };
 
 }  // namespace libp2p::multi

include/libp2p/multi/uvarint.hpp

@@ -55,7 +55,8 @@ namespace libp2p::multi {
     /// Disable to return span to inner data of temporary object
     BytesIn toBytes() const && = delete;
 
-    const std::vector<uint8_t> &toVector() const;
+    const std::vector<uint8_t> &toVector() const &;
+    std::vector<uint8_t> toVector() &&;
 
     /**
      * Assigns the varint to an unsigned integer, encoding the latter

include/libp2p/peer/peer_id.hpp

@@ -71,7 +71,8 @@ namespace libp2p::peer {
     /**
      * Creates a vector representation of PeerId.
      */
-    const std::vector<uint8_t> &toVector() const;
+    const std::vector<uint8_t> &toVector() const &;
+    std::vector<uint8_t> toVector() &&;
 
     /**
      * Get a SHA256 multihash of the peer's ID

src/multi/multihash.cpp

@@ -35,7 +35,7 @@ OUTCOME_CPP_DEFINE_CATEGORY(libp2p::multi, Multihash::Error, e) {
 namespace libp2p::multi {
 
   Multihash::Multihash(HashType type, BytesIn hash)
-      : data_(std::make_shared<const Data>(type, hash)) {}
+      : data_(std::make_shared<Data>(type, hash)) {}
 
   namespace {
     template <typename Buffer>
@@ -132,7 +132,16 @@ namespace libp2p::multi {
     return fmt::format("{:X}", data().bytes);
   }
 
-  const Bytes &Multihash::toBuffer() const {
+  const Bytes &Multihash::toBuffer() const & {
+    return data().bytes;
+  }
+
+  Bytes Multihash::toBuffer() && {
+    if (data_ && data_.use_count() == 1) {
+      auto data = std::move(data_);
+      data_ = nullptr;
+      return std::move(data->bytes);
+    }
     return data().bytes;
   }
 

src/multi/uvarint.cpp

@@ -50,10 +50,14 @@ namespace libp2p::multi {
     return bytes_;
   }
 
-  const std::vector<uint8_t> &UVarint::toVector() const {
+  const std::vector<uint8_t> &UVarint::toVector() const & {
     return bytes_;
   }
 
+  std::vector<uint8_t> UVarint::toVector() && {
+    return std::move(bytes_);
+  }
+
   size_t UVarint::size() const {
     return bytes_.size();
   }

src/peer/peer_id.cpp

@@ -81,10 +81,14 @@ namespace libp2p::peer {
     return encodeBase58(hash_.toBuffer());
   }
 
-  const std::vector<uint8_t> &PeerId::toVector() const {
+  const std::vector<uint8_t> &PeerId::toVector() const & {
     return hash_.toBuffer();
   }
 
+  std::vector<uint8_t> PeerId::toVector() && {
+    return std::move(hash_).toBuffer();
+  }
+
   std::string PeerId::toHex() const {
     return hash_.toHex();
   }