Auto merge of zcash#1602 - str4d:1424-minimal-getblocktemplate, r=daira

Minimal modifications to getblocktemplate

A simpler alternative to zcash#1435 that ensures Zcash GBT will remain compatible with BIP 22.

Closes zcash#1424

qa/pull-tester/rpc-tests.sh

@@ -31,6 +31,7 @@ testScripts=(
     'walletbackup.py'
     'zcjoinsplit.py'
     'zcjoinsplitdoublespend.py'
+    'getblocktemplate.py'
 );
 testScriptsExt=(
     'bipdersig-p2p.py'

qa/rpc-tests/getblocktemplate.py

@@ -0,0 +1,58 @@
+#!/usr/bin/env python2
+# Copyright (c) 2016 The Zcash developers
+# Distributed under the MIT software license, see the accompanying
+# file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+from test_framework.test_framework import BitcoinTestFramework
+from test_framework.util import *
+
+
+class GetBlockTemplateTest(BitcoinTestFramework):
+    '''
+    Test getblocktemplate.
+    '''
+
+    def setup_chain(self):
+        print("Initializing test directory "+self.options.tmpdir)
+        initialize_chain_clean(self.options.tmpdir, 4)
+
+    def setup_network(self, split=False):
+        self.nodes = start_nodes(2, self.options.tmpdir)
+        connect_nodes_bi(self.nodes,0,1)
+        self.is_network_split=False
+        self.sync_all()
+
+    def run_test(self):
+        node = self.nodes[0]
+        node.generate(1) # Mine a block to leave initial block download
+
+        # Test 1: Default to coinbasetxn
+        tmpl = node.getblocktemplate()
+        assert('coinbasetxn' in tmpl)
+        assert('coinbasevalue' not in tmpl)
+
+        # Test 2: Get coinbasetxn if requested
+        tmpl = node.getblocktemplate({'capabilities': ['coinbasetxn']})
+        assert('coinbasetxn' in tmpl)
+        assert('coinbasevalue' not in tmpl)
+
+        # Test 3: coinbasevalue not supported if requested
+        tmpl = node.getblocktemplate({'capabilities': ['coinbasevalue']})
+        assert('coinbasetxn' in tmpl)
+        assert('coinbasevalue' not in tmpl)
+
+        # Test 4: coinbasevalue not supported if both requested
+        tmpl = node.getblocktemplate({'capabilities': ['coinbasetxn', 'coinbasevalue']})
+        assert('coinbasetxn' in tmpl)
+        assert('coinbasevalue' not in tmpl)
+
+        # Test 5: General checks
+        tmpl = node.getblocktemplate()
+        assert(len(tmpl['noncerange']) == 16)
+
+        # Test 6: coinbasetxn checks
+        assert('foundersreward' in tmpl['coinbasetxn'])
+        assert(tmpl['coinbasetxn']['required'])
+
+if __name__ == '__main__':
+    GetBlockTemplateTest().main()

qa/rpc-tests/getblocktemplate_proposals.py

@@ -71,9 +71,11 @@ def genmrklroot(leaflist):
 def template_to_bytes(tmpl, txlist):
     blkver = pack('<L', tmpl['version'])
     mrklroot = genmrklroot(list(dblsha(a) for a in txlist))
+    reserved = b'\0'*32
     timestamp = pack('<L', tmpl['curtime'])
-    nonce = b'\0\0\0\0'
-    blk = blkver + a2b_hex(tmpl['previousblockhash'])[::-1] + mrklroot + timestamp + a2b_hex(tmpl['bits'])[::-1] + nonce
+    nonce = b'\0'*32
+    soln = b'\0'
+    blk = blkver + a2b_hex(tmpl['previousblockhash'])[::-1] + mrklroot + reserved + timestamp + a2b_hex(tmpl['bits'])[::-1] + nonce + soln
     blk += varlenEncode(len(txlist))
     for tx in txlist:
         blk += tx

src/rpcmining.cpp

@@ -389,10 +389,10 @@ Value getblocktemplate(const Array& params, bool fHelp)
             "      }\n"
             "      ,...\n"
             "  ],\n"
-            "  \"coinbaseaux\" : {                  (json object) data that should be included in the coinbase's scriptSig content\n"
-            "      \"flags\" : \"flags\"            (string) \n"
-            "  },\n"
-            "  \"coinbasevalue\" : n,               (numeric) maximum allowable input to coinbase transaction, including the generation award and transaction fees (in Satoshis)\n"
+//            "  \"coinbaseaux\" : {                  (json object) data that should be included in the coinbase's scriptSig content\n"
+//            "      \"flags\" : \"flags\"            (string) \n"
+//            "  },\n"
+//            "  \"coinbasevalue\" : n,               (numeric) maximum allowable input to coinbase transaction, including the generation award and transaction fees (in Satoshis)\n"
             "  \"coinbasetxn\" : { ... },           (json object) information for coinbase transaction\n"
             "  \"target\" : \"xxxx\",               (string) The hash target\n"
             "  \"mintime\" : xxx,                   (numeric) The minimum timestamp appropriate for next block time in seconds since epoch (Jan 1 1970 GMT)\n"
@@ -415,8 +415,15 @@ Value getblocktemplate(const Array& params, bool fHelp)
 
     LOCK(cs_main);
 
+    // Wallet is required because we support coinbasetxn
+    if (pwalletMain == NULL) {
+        throw JSONRPCError(RPC_METHOD_NOT_FOUND, "Method not found (disabled)");
+    }
+
     std::string strMode = "template";
     Value lpval = Value::null;
+    // TODO: Re-enable coinbasevalue once a specification has been written
+    bool coinbasetxn = true;
     if (params.size() > 0)
     {
         const Object& oparam = params[0].get_obj();
@@ -529,7 +536,7 @@ Value getblocktemplate(const Array& params, bool fHelp)
         // Clear pindexPrev so future calls make a new block, despite any failures from here on
         pindexPrev = NULL;
 
-        // Store the pindexBest used before CreateNewBlock, to avoid races
+        // Store the pindexBest used before CreateNewBlockWithKey, to avoid races
         nTransactionsUpdatedLast = mempool.GetTransactionsUpdated();
         CBlockIndex* pindexPrevNew = chainActive.Tip();
         nStart = GetTime();
@@ -540,12 +547,12 @@ Value getblocktemplate(const Array& params, bool fHelp)
             delete pblocktemplate;
             pblocktemplate = NULL;
         }
-        CScript scriptDummy = CScript() << OP_TRUE;
-        pblocktemplate = CreateNewBlock(scriptDummy);
+        CReserveKey reservekey(pwalletMain);
+        pblocktemplate = CreateNewBlockWithKey(reservekey);
         if (!pblocktemplate)
             throw JSONRPCError(RPC_OUT_OF_MEMORY, "Out of memory");
 
-        // Need to update only after we know CreateNewBlock succeeded
+        // Need to update only after we know CreateNewBlockWithKey succeeded
         pindexPrev = pindexPrevNew;
     }
     CBlock* pblock = &pblocktemplate->block; // pointer for convenience
@@ -556,6 +563,7 @@ Value getblocktemplate(const Array& params, bool fHelp)
 
     static const Array aCaps = boost::assign::list_of("proposal");
 
+    Value txCoinbase = Value::null;
     Array transactions;
     map<uint256, int64_t> setTxIndex;
     int i = 0;
@@ -564,7 +572,7 @@ Value getblocktemplate(const Array& params, bool fHelp)
         uint256 txHash = tx.GetHash();
         setTxIndex[txHash] = i++;
 
-        if (tx.IsCoinBase())
+        if (tx.IsCoinBase() && !coinbasetxn)
             continue;
 
         Object entry;
@@ -585,7 +593,17 @@ Value getblocktemplate(const Array& params, bool fHelp)
         entry.push_back(Pair("fee", pblocktemplate->vTxFees[index_in_template]));
         entry.push_back(Pair("sigops", pblocktemplate->vTxSigOps[index_in_template]));
 
-        transactions.push_back(entry);
+        if (tx.IsCoinBase()) {
+            // Show founders' reward if it is required
+            if (pblock->vtx[0].vout.size() > 1) {
+                // Correct this if GetBlockTemplate changes the order
+                entry.push_back(Pair("foundersreward", (int64_t)tx.vout[1].nValue));
+            }
+            entry.push_back(Pair("required", true));
+            txCoinbase = entry;
+        } else {
+            transactions.push_back(entry);
+        }
     }
 
     Object aux;
@@ -606,8 +624,13 @@ Value getblocktemplate(const Array& params, bool fHelp)
     result.push_back(Pair("version", pblock->nVersion));
     result.push_back(Pair("previousblockhash", pblock->hashPrevBlock.GetHex()));
     result.push_back(Pair("transactions", transactions));
-    result.push_back(Pair("coinbaseaux", aux));
-    result.push_back(Pair("coinbasevalue", (int64_t)pblock->vtx[0].vout[0].nValue));
+    if (coinbasetxn) {
+        assert(txCoinbase.type() == obj_type);
+        result.push_back(Pair("coinbasetxn", txCoinbase));
+    } else {
+        result.push_back(Pair("coinbaseaux", aux));
+        result.push_back(Pair("coinbasevalue", (int64_t)pblock->vtx[0].vout[0].nValue));
+    }
     result.push_back(Pair("longpollid", chainActive.Tip()->GetBlockHash().GetHex() + i64tostr(nTransactionsUpdatedLast)));
     result.push_back(Pair("target", hashTarget.GetHex()));
     result.push_back(Pair("mintime", (int64_t)pindexPrev->GetMedianTimePast()+1));