From 6f741e5583a1085ef1ab89193e8a066c5f56b56b Mon Sep 17 00:00:00 2001
From: "Wladimir J. van der Laan" <laanwj@gmail.com>
Date: Wed, 3 May 2017 08:14:50 +0200
Subject: [PATCH] Merge #9733: Add getchaintxstats RPC

bd1f138 Add getchaintxstats RPC (Pieter Wuille)

Tree-SHA512: 270785b25e7e2faad4528b5ef591d9dc6266f15236563e3f02dac1f2d9ce3732c4d44903fcccf38549f7921f29d1a93cb0a118b7453ccc5afd79739b51e68f46
---
 src/rpc/blockchain.cpp | 66 ++++++++++++++++++++++++++++++++++++++++++
 src/rpc/client.cpp     |  1 +
 2 files changed, 67 insertions(+)

diff --git a/src/rpc/blockchain.cpp b/src/rpc/blockchain.cpp
index 7df8fb3f5a..90f8e005d0 100644
--- a/src/rpc/blockchain.cpp
+++ b/src/rpc/blockchain.cpp
@@ -1727,6 +1727,71 @@ UniValue reconsiderblock(const JSONRPCRequest& request)
     return NullUniValue;
 }
 
+UniValue getchaintxstats(const JSONRPCRequest& request)
+{
+    if (request.fHelp || request.params.size() > 2)
+        throw std::runtime_error(
+            "getchaintxstats ( nblocks blockhash )\n"
+            "\nCompute statistics about the total number and rate of transactions in the chain.\n"
+            "\nArguments:\n"
+            "1. nblocks      (numeric, optional) Size of the window in number of blocks (default: one month).\n"
+            "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"
+            "}\n"
+            "\nExamples:\n"
+            + HelpExampleCli("getchaintxstats", "")
+            + HelpExampleRpc("getchaintxstats", "2016")
+        );
+
+    const CBlockIndex* pindex;
+    int blockcount = 30 * 24 * 60 * 60 / Params().GetConsensus().nPowTargetSpacing; // By default: 1 month
+
+    if (request.params.size() > 0 && !request.params[0].isNull()) {
+        blockcount = request.params[0].get_int();
+    }
+
+    bool havehash = request.params.size() > 1 && !request.params[1].isNull();
+    uint256 hash;
+    if (havehash) {
+        hash = uint256S(request.params[1].get_str());
+    }
+
+    {
+        LOCK(cs_main);
+        if (havehash) {
+            auto it = mapBlockIndex.find(hash);
+            if (it == mapBlockIndex.end()) {
+                throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "Block not found");
+            }
+            pindex = it->second;
+            if (!chainActive.Contains(pindex)) {
+                throw JSONRPCError(RPC_INVALID_PARAMETER, "Block is not in main chain");
+            }
+        } else {
+            pindex = chainActive.Tip();
+        }
+    }
+
+    if (blockcount < 1 || blockcount >= pindex->nHeight) {
+        throw JSONRPCError(RPC_INVALID_PARAMETER, "Invalid block count: should be between 1 and the block's height");
+    }
+
+    const CBlockIndex* pindexPast = pindex->GetAncestor(pindex->nHeight - blockcount);
+    int nTimeDiff = pindex->GetMedianTimePast() - pindexPast->GetMedianTimePast();
+    int nTxDiff = pindex->nChainTx - pindexPast->nChainTx;
+
+    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));
+
+    return ret;
+}
+
 UniValue getspecialtxes(const JSONRPCRequest& request)
 {
     if (request.fHelp || request.params.size() < 1 || request.params.size() > 5)
@@ -1838,6 +1903,7 @@ static const CRPCCommand commands[] =
 { //  category              name                      actor (function)         okSafe argNames
   //  --------------------- ------------------------  -----------------------  ------ ----------
     { "blockchain",         "getblockchaininfo",      &getblockchaininfo,      true,  {} },
+    { "blockchain",         "getchaintxstats",        &getchaintxstats,        true,  {"nblocks", "blockhash"} },
     { "blockchain",         "getbestblockhash",       &getbestblockhash,       true,  {} },
     { "blockchain",         "getblockcount",          &getblockcount,          true,  {} },
     { "blockchain",         "getblock",               &getblock,               true,  {"blockhash","verbosity|verbose"} },
diff --git a/src/rpc/client.cpp b/src/rpc/client.cpp
index 03cdd9cda1..05455a032b 100644
--- a/src/rpc/client.cpp
+++ b/src/rpc/client.cpp
@@ -103,6 +103,7 @@ static const CRPCConvertParam vRPCConvertParams[] =
     { "getblockheader", 1, "verbose" },
     { "getblockheaders", 1, "count" },
     { "getblockheaders", 2, "verbose" },
+    { "getchaintxstats", 0, "nblocks" },
     { "getmerkleblocks", 2, "count" },
     { "gettransaction", 1, "include_watchonly" },
     { "getrawtransaction", 1, "verbose" },