WIP add 'top N only' feature to gensnapshot rpc

src/main.cpp

@@ -588,7 +588,7 @@ CBlockTreeDB *pblocktree = NULL;
 #define KOMODO_ZCASH
 #include "komodo.h"
 
-UniValue komodo_snapshot()
+UniValue komodo_snapshot(int top)
 {
     LOCK(cs_main);
     int64_t total = -1;
@@ -596,7 +596,7 @@ UniValue komodo_snapshot()
 
     if (fAddressIndex) {
 	    if ( pblocktree != 0 ) {
-		result = pblocktree->Snapshot();
+		result = pblocktree->Snapshot(top);
 	    } else {
 		fprintf(stderr,"null pblocktree start with -addressindex=true\n");
 	    }

src/rpcmisc.cpp

@@ -1015,18 +1015,53 @@ UniValue getaddressbalance(const UniValue& params, bool fHelp)
 
 }
 
-UniValue komodo_snapshot();
+UniValue komodo_snapshot(int top);
 
 UniValue getsnapshot(const UniValue& params, bool fHelp)
 {
-    UniValue result(UniValue::VOBJ); int64_t total;
+    UniValue result(UniValue::VOBJ); int64_t total; int top = 0;
-    if ( fHelp || params.size() > 0 )
+
+    if (params.size() > 0 && !params[0].isNull()) {
+        top = params[0].get_str();
+	fprintf(stderr, "top=%s\n",top);
+	if (top <= 0)
+	    throw JSONRPCError(RPC_INVALID_PARAMETER, "Invalid parameter, top must be a positive integer");
+    }
+
+    if ( fHelp || params.size() > 1)
     {
         throw runtime_error(
                             "getsnapshot\n"
+			    "\nReturns a snapshot of (address,amount) pairs at current height (requires addressindex to be enabled).\n"
+			    "\nArguments:\n"
+			    "  \"top\" (number, optional) Only return this many addresses, i.e. top N richlist\n"
+			    "\nResult:\n"
+			    "{\n"
+			    "   \"addresses\": [\n"
+			    "    {\n"
+			    "      \"addr\": \"RMEBhzvATA8mrfVK82E5TgPzzjtaggRGN3\",\n"
+			    "      \"amount\": \"100.0\"\n"
+			    "    },\n"
+			    "    {\n"
+			    "      \"addr\": \"RqEBhzvATAJmrfVL82E57gPzzjtaggR777\",\n"
+			    "      \"amount\": \"23.45\"\n"
+			    "    }\n"
+			    "  ],\n"
+			    "  \"total\": 123.45           (numeric) Total amount in snapshot\n"
+			    "  \"average\": 61.7,          (numeric) Average amount in each address \n"
+			    "  \"utxos\": 14,              (number) Total number of UTXOs in snapshot\n"
+			    "  \"total_addresses\": 2,     (number) Total number of addresses in snapshot,\n"
+			    "  \"start_height\": 91,       (number) Block height snapshot began\n"
+			    "  \"ending_height\": 91       (number) Block height snapsho finished,\n"
+			    "  \"start_time\": 1531982752, (number) Unix epoch time snapshot started\n"
+			    "  \"end_time\": 1531982752    (number) Unix epoch time snapshot finished\n"
+			    "}\n"
+			    "\nExamples:\n"
+			    + HelpExampleCli("getsnapshot","")
+			    + HelpExampleRpc("getsnapshot", "1000")
                             );
     }
-    result = komodo_snapshot();
+    result = komodo_snapshot(top);
     if ( result.size() > 0 ) {
         result.push_back(Pair("end_time", time(NULL)));
     } else {

src/txdb.cpp

@@ -399,7 +399,7 @@ bool CBlockTreeDB::ReadAddressIndex(uint160 addressHash, int type,
 
 bool getAddressFromIndex(const int &type, const uint160 &hash, std::string &address);
 
-extern UniValue CBlockTreeDB::Snapshot()
+extern UniValue CBlockTreeDB::Snapshot(int top)
 {
     char chType; int64_t total = 0; int64_t totalAddresses = 0; std::string address;
     int64_t utxos = 0; int64_t ignoredAddresses;
@@ -472,7 +472,7 @@ extern UniValue CBlockTreeDB::Snapshot()
 			addressAmounts[address] += nValue;
 		    }
 		    //fprintf(stderr,"{\"%s\", %.8f},\n",address.c_str(),(double)nValue/COIN);
-		    total += nValue;
+		    // total += nValue;
 		    utxos++;
                 } catch (const std::exception& e) {
 		    fprintf(stderr, "DONE %s: LevelDB addressindex exception! - %s\n", __func__, e.what());
@@ -495,21 +495,33 @@ extern UniValue CBlockTreeDB::Snapshot()
 
     UniValue obj(UniValue::VOBJ);
     UniValue addressesSorted(UniValue::VARR);
+    int topN = 0;
     for (std::vector<std::pair<CAmount, std::string>>::iterator it = vaddr.begin(); it!=vaddr.end(); ++it) {
 	UniValue obj(UniValue::VOBJ);
 	obj.push_back( make_pair("addr", it->second.c_str() ) );
 	char amount[32];
 	sprintf(amount, "%.8f", (double) it->first / COIN);
 	obj.push_back( make_pair("amount", amount) );
+	total += it->first;
 	addressesSorted.push_back(obj);
+	topN++;
+	// If requested, only show top N addresses in output JSON
+ 	if (top == topN)
+	    break;
     }
 
+    if (top)
+	totalAddresses = top;
+
     if (totalAddresses > 0) {
+	// Array of all addreses with balances
         result.push_back(make_pair("addresses", addressesSorted));
+	// Total amount in this snapshot, which is less than circulating supply if top parameter is used
         result.push_back(make_pair("total", (double) total / COIN ));
+	// Average amount in each address of this snapshot
         result.push_back(make_pair("average",(double) (total/COIN) / totalAddresses ));
     }
-    // Total number of utxos in this snaphot
+    // Total number of utxos processed in this snaphot
     result.push_back(make_pair("utxos", utxos));
     // Total number of addresses in this snaphot
     result.push_back(make_pair("total_addresses", totalAddresses));

src/txdb.h

@@ -95,7 +95,7 @@ public:
     bool ReadFlag(const std::string &name, bool &fValue);
     bool LoadBlockIndexGuts();
     bool blockOnchainActive(const uint256 &hash);
-    UniValue Snapshot();
+    UniValue Snapshot(int top);
 };
 
 #endif // BITCOIN_TXDB_H