Merge #11021: [rpc] fix getchaintxstats()

07704c1 Add some tests for getchaintxstats (Akio Nakamura)
3336676 Fix getchaintxstats() (Akio Nakamura)

Pull request description:

  1. calculate nblocks more adaptive.
    -> set default nblocks to min (blocks for 1 month, target block's height - 1)
    -> before PR: if not specify nblocks-parameter, illegal parameter error will happen when target block height is below nblocks.
  2. correct error message.
    -> nblocks accepts [1 .. block's height -1] . so add a word "-1".
  3. add check 0-divide.
    -> if nTimeDiff = 0 then use UniValue(UniValue::VNULL) and returns {... "txrate": null} .
    -> before PR: if nTimeDiff = 0 then returns {... "txrate":} and bitcoin-cli cannot handle the response.

Tree-SHA512: e1962ce7bb05a5bc7dec03eb04a8e7578f50fdb68927fcfc0a2232905ef4d679293eee148ebe0866682d209a8c458d21fbe71715e7311adb81f37089aae1ed93

2 files changed, 44 insertions, 10 deletions

diff --git a/src/rpc/blockchain.cpp b/src/rpc/blockchain.cpp
index 8c0268e264..19074d3d95 100644
--- a/src/rpc/blockchain.cpp
+++ b/src/rpc/blockchain.cpp
@@ -1484,9 +1484,12 @@ UniValue getchaintxstats(const JSONRPCRequest& request)
             "2. \"blockhash\"  (string, optional) The hash of the block that ends the window.\n"
             "\nResult:\n"
             "{\n"
-            "  \"time\": xxxxx,        (numeric) The timestamp for the statistics in UNIX format.\n"
-            "  \"txcount\": xxxxx,     (numeric) The total number of transactions in the chain up to that point.\n"
-            "  \"txrate\": x.xx,       (numeric) The average rate of transactions per second in the window.\n"
+            "  \"time\": xxxxx,                (numeric) The timestamp for the final block in the window in UNIX format.\n"
+            "  \"txcount\": xxxxx,             (numeric) The total number of transactions in the chain up to that point.\n"
+            "  \"window_block_count\": xxxxx,  (numeric) Size of the window in number of blocks.\n"
+            "  \"window_tx_count\": xxxxx,     (numeric) The number of transactions in the window. Only returned if \"window_block_count\" is > 0.\n"
+            "  \"window_interval\": xxxxx,     (numeric) The elapsed time in the window in seconds. Only returned if \"window_block_count\" is > 0.\n"
+            "  \"txrate\": x.xx,               (numeric) The average rate of transactions per second in the window. Only returned if \"window_interval\" is > 0.\n"
             "}\n"
             "\nExamples:\n"
             + HelpExampleCli("getchaintxstats", "")
@@ -1496,10 +1499,6 @@ UniValue getchaintxstats(const JSONRPCRequest& request)
     const CBlockIndex* pindex;
     int blockcount = 30 * 24 * 60 * 60 / Params().GetConsensus().nPowTargetSpacing; // By default: 1 month
 
-    if (!request.params[0].isNull()) {
-        blockcount = request.params[0].get_int();
-    }
-
     bool havehash = !request.params[1].isNull();
     uint256 hash;
     if (havehash) {
@@ -1524,8 +1523,14 @@ UniValue getchaintxstats(const JSONRPCRequest& request)
     
     assert(pindex != nullptr);
 
-    if (blockcount < 1 || blockcount >= pindex->nHeight) {
-        throw JSONRPCError(RPC_INVALID_PARAMETER, "Invalid block count: should be between 1 and the block's height");
+    if (request.params[0].isNull()) {
+        blockcount = std::max(0, std::min(blockcount, pindex->nHeight - 1));
+    } else {
+        blockcount = request.params[0].get_int();
+
+        if (blockcount < 0 || (blockcount > 0 && blockcount >= pindex->nHeight)) {
+            throw JSONRPCError(RPC_INVALID_PARAMETER, "Invalid block count: should be between 0 and the block's height - 1");
+        }
     }
 
     const CBlockIndex* pindexPast = pindex->GetAncestor(pindex->nHeight - blockcount);
@@ -1535,7 +1540,14 @@ UniValue getchaintxstats(const JSONRPCRequest& request)
     UniValue ret(UniValue::VOBJ);
     ret.push_back(Pair("time", (int64_t)pindex->nTime));
     ret.push_back(Pair("txcount", (int64_t)pindex->nChainTx));
-    ret.push_back(Pair("txrate", ((double)nTxDiff) / nTimeDiff));
+    ret.push_back(Pair("window_block_count", blockcount));
+    if (blockcount > 0) {
+        ret.push_back(Pair("window_tx_count", nTxDiff));
+        ret.push_back(Pair("window_interval", nTimeDiff));
+        if (nTimeDiff > 0) {
+            ret.push_back(Pair("txrate", ((double)nTxDiff) / nTimeDiff));
+        }
+    }
 
     return ret;
 }
diff --git a/test/functional/blockchain.py b/test/functional/blockchain.py
index c5967aa10b..5bd3bc8f83 100755
--- a/test/functional/blockchain.py
+++ b/test/functional/blockchain.py
@@ -81,6 +81,28 @@ class BlockchainTest(BitcoinTestFramework):
         # we have to round because of binary math
         assert_equal(round(chaintxstats['txrate'] * 600, 10), Decimal(1))
 
+        b1 = self.nodes[0].getblock(self.nodes[0].getblockhash(1))
+        b200 = self.nodes[0].getblock(self.nodes[0].getblockhash(200))
+        time_diff = b200['mediantime'] - b1['mediantime']
+
+        chaintxstats = self.nodes[0].getchaintxstats()
+        assert_equal(chaintxstats['time'], b200['time'])
+        assert_equal(chaintxstats['txcount'], 201)
+        assert_equal(chaintxstats['window_block_count'], 199)
+        assert_equal(chaintxstats['window_tx_count'], 199)
+        assert_equal(chaintxstats['window_interval'], time_diff)
+        assert_equal(round(chaintxstats['txrate'] * time_diff, 10), Decimal(199))
+
+        chaintxstats = self.nodes[0].getchaintxstats(blockhash=b1['hash'])
+        assert_equal(chaintxstats['time'], b1['time'])
+        assert_equal(chaintxstats['txcount'], 2)
+        assert_equal(chaintxstats['window_block_count'], 0)
+        assert('window_tx_count' not in chaintxstats)
+        assert('window_interval' not in chaintxstats)
+        assert('txrate' not in chaintxstats)
+
+        assert_raises_jsonrpc(-8, "Invalid block count: should be between 0 and the block's height - 1", self.nodes[0].getchaintxstats, 201)
+
     def _test_gettxoutsetinfo(self):
         node = self.nodes[0]
         res = node.gettxoutsetinfo()