chore: Add comments to SignerEntries.h (XRPLF#5059)

src/xrpld/app/tx/detail/SignerEntries.cpp

@@ -30,7 +30,7 @@ Expected<std::vector<SignerEntries::SignerEntry>, NotTEC>
 SignerEntries::deserialize(
  STObject const& obj,
  beast::Journal journal,
- std::string const& annotation)
+ std::string_view annotation)
 {
  std::pair<std::vector<SignerEntry>, NotTEC> s;
 

src/xrpld/app/tx/detail/SignerEntries.h

@@ -27,18 +27,27 @@
 #include <xrpl/protocol/STTx.h> // STTx::maxMultiSigners
 #include <xrpl/protocol/TER.h> // temMALFORMED
 #include <xrpl/protocol/UintTypes.h> // AccountID
+
 #include <optional>
+#include <string_view>
 
 namespace ripple {
 
 // Forward declarations
 class STObject;
 
-// Support for SignerEntries that is needed by a few Transactors
+// Support for SignerEntries that is needed by a few Transactors.
+//
+// SignerEntries is represented as a std::vector<SignerEntries::SignerEntry>.
+// There is no direct constructor for SignerEntries.
+//
+// o A std::vector<SignerEntries::SignerEntry> is a SignerEntries.
+// o More commonly, SignerEntries are extracted from an STObject by
+// calling SignerEntries::deserialize().
 class SignerEntries
 {
 public:
- explicit SignerEntries() = default;
+ explicit SignerEntries() = delete;
 
  struct SignerEntry
  {
@@ -69,11 +78,15 @@ class SignerEntries
  };
 
  // Deserialize a SignerEntries array from the network or from the ledger.
+ //
+ // obj Contains a SignerEntries field that is an STArray.
+ // journal For reporting error conditions.
+ // annotation Source of SignerEntries, like "ledger" or "transaction".
  static Expected<std::vector<SignerEntry>, NotTEC>
  deserialize(
  STObject const& obj,
  beast::Journal journal,
- std::string const& annotation);
+ std::string_view annotation);
 };
 
 } // namespace ripple