commit 197e5659507305a995597f8e6c3fd2b0648ad051
author Alexander Afanasyev <alexander.afanasyev@ucla.edu> Fri Jun 13 16:56:31 2014 -0700
committer Alexander Afanasyev <alexander.afanasyev@ucla.edu> Fri Jun 13 20:14:30 2014 -0700
tree 8147e39badfbe756ac771a8113002c93a5c36e0c
parent b578ab33591cdb5f987a70368ce6884bfc3c407e

data: Optimize Data signing

As of this commit, KeyChain::sign pre-allocates EncodingBuffer, requests
unsigned portion of Data using Data::wireEncode(EncodingBuffer, true),
and then appends the resulting signature and prepends Data packet
header.  This way there is no extra memory allocation after Data packet
is signed.

Change-Id: I670e9a2f1d6f5e9b049f41b47f011af384f32c95

src/security/key-chain.hpp

diff --git a/src/security/key-chain.hpp b/src/security/key-chain.hpp
index dcf2079..7c95e14 100644
--- a/src/security/key-chain.hpp
+++ b/src/security/key-chain.hpp
@@ -871,10 +871,13 @@
                             const Name& keyName, DigestAlgorithm digestAlgorithm)
 {
   data.setSignature(signature);
-  data.setSignatureValue(m_tpm->signInTpm(data.wireEncode().value(),
-                                          data.wireEncode().value_size() -
-                                          data.getSignature().getValue().size(),
-                                          keyName, digestAlgorithm));
+
+  EncodingBuffer encoder;
+  data.wireEncode(encoder, true);
+
+  Block signatureValue = m_tpm->signInTpm(encoder.buf(), encoder.size(),
+                                          keyName, digestAlgorithm);
+  data.wireEncode(encoder, signatureValue);
 }
 
 inline void