Add random IO buffer generation

Summary: Moves random IO buffer generation into Factory base for reusability.

Reviewed By: mingtaoy

Differential Revision: D65498181

fbshipit-source-id: 05729cfcb484dcd8d34c9772603fe3cf573f820b

fizz/client/ClientProtocol.cpp

@@ -793,17 +793,6 @@ static ClientHello constructEncryptedClientHello(
   return chloOuter;
 }
 
-static std::unique_ptr<folly::IOBuf> randomIOBuf(
-    const Factory& factory,
-    size_t count) {
-  auto buf = folly::IOBuf::create(count);
-  if (count > 0) {
-    factory.makeRandomBytes(buf->writableData(), count);
-    buf->append(count);
-  }
-  return buf;
-}
-
 Actions
 EventHandler<ClientTypes, StateEnum::Uninitialized, Event::Connect>::handle(
     const State& /*state*/,
@@ -846,7 +835,7 @@ EventHandler<ClientTypes, StateEnum::Uninitialized, Event::Connect>::handle(
   Buf legacySessionId;
   if (context->getCompatibilityMode()) {
     constexpr size_t kRandomSize = Random().size();
-    legacySessionId = randomIOBuf(*context->getFactory(), kRandomSize);
+    legacySessionId = context->getFactory()->makeRandomIOBuf(kRandomSize);
   } else {
     legacySessionId = folly::IOBuf::create(0);
   }

fizz/protocol/Factory.cpp

@@ -50,4 +50,13 @@ std::unique_ptr<KeyDerivation> Factory::makeKeyDeriver(
 std::shared_ptr<Cert> Factory::makeIdentityOnlyCert(std::string ident) const {
   return std::make_shared<IdentityCert>(std::move(ident));
 }
+
+Buf Factory::makeRandomIOBuf(size_t size) const {
+  auto buf = folly::IOBuf::create(size);
+  if (size > 0) {
+    makeRandomBytes(buf->writableData(), size);
+    buf->append(size);
+  }
+  return buf;
+}
 } // namespace fizz

fizz/protocol/Factory.h

@@ -97,5 +97,7 @@ class Factory {
    * Should not be overridden *unless* for testing.
    */
   virtual std::shared_ptr<Cert> makeIdentityOnlyCert(std::string ident) const;
+
+  Buf makeRandomIOBuf(size_t size) const;
 };
 } // namespace fizz

fizz/protocol/ech/Encryption.cpp

@@ -396,16 +396,6 @@ void setAcceptConfirmation(
 
 namespace {
 
-static std::unique_ptr<folly::IOBuf> randomIOBuf(
-    const Factory& factory,
-    size_t count) {
-  auto buf = folly::IOBuf::create(count);
-  if (count > 0) {
-    factory.makeRandomBytes(buf->writableData(), count);
-    buf->append(count);
-  }
-  return buf;
-}
 // GREASE PSKs are essentially the same size as the source PSK with the actual
 // contents of all fields replaced with random data. For the HRR case, the PSK
 // identity is preserved.
@@ -421,7 +411,7 @@ ClientPresharedKey generateGreasePskCommon(
       greaseIdentity.psk_identity = identity.psk_identity->clone();
     } else {
       size_t identitySize = identity.psk_identity->computeChainDataLength();
-      greaseIdentity.psk_identity = randomIOBuf(*factory, identitySize);
+      greaseIdentity.psk_identity = factory->makeRandomIOBuf(identitySize);
     }
 
     factory->makeRandomBytes(
@@ -432,7 +422,7 @@ ClientPresharedKey generateGreasePskCommon(
     const auto& binder = source.binders.at(i);
     PskBinder greaseBinder;
     size_t binderSize = binder.binder->computeChainDataLength();
-    greaseBinder.binder = randomIOBuf(*factory, binderSize);
+    greaseBinder.binder = factory->makeRandomIOBuf(binderSize);
     grease.binders.push_back(std::move(greaseBinder));
   }
   return grease;