From 02b68885a0fbecb1d5a8d2a52fe566b1c6fa127b Mon Sep 17 00:00:00 2001
From: Alexander Block <ablock84@gmail.com>
Date: Fri, 15 Feb 2019 14:11:47 +0100
Subject: [PATCH] Implement CBLSLazySignature for lazy
 serialization/deserialization

In some cases it takes too much time to perform full deserialization of
BLS signatures in the message handler thread. Better to just read the
buffer and do the actual deserialization when the signature is needed for
the first time (which is can be in another thread).
---
 src/bls/bls.cpp | 28 ++++++++++++++++++++++++++++
 src/bls/bls.h   | 39 +++++++++++++++++++++++++++++++++++++++
 2 files changed, 67 insertions(+)

diff --git a/src/bls/bls.cpp b/src/bls/bls.cpp
index bb44f5029..534fd8ad0 100644
--- a/src/bls/bls.cpp
+++ b/src/bls/bls.cpp
@@ -423,6 +423,34 @@ bool CBLSSignature::Recover(const std::vector<CBLSSignature>& sigs, const std::v
     return true;
 }
 
+CBLSLazySignature::CBLSLazySignature(CBLSSignature& _sig) :
+    bufValid(false),
+    sigInitialized(true),
+    sig(_sig)
+{
+
+}
+
+void CBLSLazySignature::SetSig(const CBLSSignature& _sig)
+{
+    bufValid = false;
+    sigInitialized = true;
+    sig = _sig;
+}
+
+const CBLSSignature& CBLSLazySignature::GetSig() const
+{
+    if (!bufValid && !sigInitialized) {
+        static CBLSSignature invalidSig;
+        return invalidSig;
+    }
+    if (!sigInitialized) {
+        sig.SetBuf(buf, sizeof(buf));
+        sigInitialized = true;
+    }
+    return sig;
+}
+
 #ifndef BUILD_BITCOIN_INTERNAL
 
 static std::once_flag init_flag;
diff --git a/src/bls/bls.h b/src/bls/bls.h
index 3c953050c..01f730244 100644
--- a/src/bls/bls.h
+++ b/src/bls/bls.h
@@ -308,6 +308,45 @@ protected:
     bool InternalGetBuf(void* buf) const;
 };
 
+class CBLSLazySignature
+{
+private:
+    mutable char buf[BLS_CURVE_SIG_SIZE];
+    mutable bool bufValid{false};
+
+    mutable CBLSSignature sig;
+    mutable bool sigInitialized{false};
+
+public:
+    template<typename Stream>
+    inline void Serialize(Stream& s) const
+    {
+        if (!sigInitialized && !bufValid) {
+            throw std::ios_base::failure("sig and buf not initialized");
+        }
+        if (!bufValid) {
+            sig.GetBuf(buf, sizeof(buf));
+            bufValid = true;
+        }
+        s.write(buf, sizeof(buf));
+    }
+
+    template<typename Stream>
+    inline void Unserialize(Stream& s)
+    {
+        s.read(buf, sizeof(buf));
+        bufValid = true;
+        sigInitialized = false;
+    }
+
+public:
+    CBLSLazySignature() = default;
+    CBLSLazySignature(CBLSSignature& _sig);
+
+    void SetSig(const CBLSSignature& _sig);
+    const CBLSSignature& GetSig() const;
+};
+
 typedef std::vector<CBLSId> BLSIdVector;
 typedef std::vector<CBLSPublicKey> BLSVerificationVector;
 typedef std::vector<CBLSPublicKey> BLSPublicKeyVector;