From 8687a0ebbc2efcb52c72fc0e34f762a1b9448cbe Mon Sep 17 00:00:00 2001
From: Jeff Garzik <jgarzik@bitpay.com>
Date: Wed, 3 Jul 2013 11:02:29 -0400
Subject: [PATCH] RPC: add getbestblockhash, to return tip of best chain

---
 src/bitcoinrpc.cpp    | 1 +
 src/bitcoinrpc.h      | 1 +
 src/rpcblockchain.cpp | 9 +++++++++
 3 files changed, 11 insertions(+)

diff --git a/src/bitcoinrpc.cpp b/src/bitcoinrpc.cpp
index 93b4d035d..b51a78be0 100644
--- a/src/bitcoinrpc.cpp
+++ b/src/bitcoinrpc.cpp
@@ -202,6 +202,7 @@ static const CRPCCommand vRPCCommands[] =
     { "help",                   &help,                   true,      true },
     { "stop",                   &stop,                   true,      true },
     { "getblockcount",          &getblockcount,          true,      false },
+    { "getbestblockhash",       &getbestblockhash,       true,      false },
     { "getconnectioncount",     &getconnectioncount,     true,      false },
     { "getpeerinfo",            &getpeerinfo,            true,      false },
     { "addnode",                &addnode,                true,      true },
diff --git a/src/bitcoinrpc.h b/src/bitcoinrpc.h
index f7f06c671..36ebb0689 100644
--- a/src/bitcoinrpc.h
+++ b/src/bitcoinrpc.h
@@ -192,6 +192,7 @@ extern json_spirit::Value signrawtransaction(const json_spirit::Array& params, b
 extern json_spirit::Value sendrawtransaction(const json_spirit::Array& params, bool fHelp);
 
 extern json_spirit::Value getblockcount(const json_spirit::Array& params, bool fHelp); // in rpcblockchain.cpp
+extern json_spirit::Value getbestblockhash(const json_spirit::Array& params, bool fHelp);
 extern json_spirit::Value getdifficulty(const json_spirit::Array& params, bool fHelp);
 extern json_spirit::Value settxfee(const json_spirit::Array& params, bool fHelp);
 extern json_spirit::Value setmininput(const json_spirit::Array& params, bool fHelp);
diff --git a/src/rpcblockchain.cpp b/src/rpcblockchain.cpp
index 49572821b..b6e962b89 100644
--- a/src/rpcblockchain.cpp
+++ b/src/rpcblockchain.cpp
@@ -81,6 +81,15 @@ Value getblockcount(const Array& params, bool fHelp)
     return nBestHeight;
 }
 
+Value getbestblockhash(const Array& params, bool fHelp)
+{
+    if (fHelp || params.size() != 0)
+        throw runtime_error(
+            "getbestblockhash\n"
+            "Returns the hash of the best (tip) block in the longest block chain.");
+
+    return hashBestChain.GetHex();
+}
 
 Value getdifficulty(const Array& params, bool fHelp)
 {