[rpc] getblockchaininfo: add size_on_disk, prune_target_size, automatic_pruning

Fix pruneheight help text.
Move fPruneMode block to match output ordering with help text.
Add functional tests for new fields in getblockchaininfo.

src/rpc/blockchain.cpp

@@ -1136,8 +1136,11 @@ UniValue getblockchaininfo(const JSONRPCRequest& request)
             "  \"mediantime\": xxxxxx,     (numeric) median time for the current best block\n"
             "  \"verificationprogress\": xxxx, (numeric) estimate of verification progress [0..1]\n"
             "  \"chainwork\": \"xxxx\"     (string) total amount of work in active chain, in hexadecimal\n"
+            "  \"size_on_disk\": xxxxxx,   (numeric) the estimated size of the block and undo files on disk\n"
             "  \"pruned\": xx,             (boolean) if the blocks are subject to pruning\n"
-            "  \"pruneheight\": xxxxxx,    (numeric) lowest-height complete block stored\n"
+            "  \"pruneheight\": xxxxxx,    (numeric) lowest-height complete block stored (only present if pruning is enabled)\n"
+            "  \"automatic_pruning\": xx,  (boolean) whether automatic pruning is enabled (only present if pruning is enabled)\n"
+            "  \"prune_target_size\": xxxxxx,  (numeric) the target size used by pruning (only present if automatic pruning is enabled)\n"
             "  \"softforks\": [            (array) status of softforks in progress\n"
             "     {\n"
             "        \"id\": \"xxxx\",        (string) name of softfork\n"
@@ -1181,7 +1184,24 @@ UniValue getblockchaininfo(const JSONRPCRequest& request)
     obj.push_back(Pair("mediantime",            (int64_t)chainActive.Tip()->GetMedianTimePast()));
     obj.push_back(Pair("verificationprogress",  GuessVerificationProgress(Params().TxData(), chainActive.Tip())));
     obj.push_back(Pair("chainwork",             chainActive.Tip()->nChainWork.GetHex()));
+    obj.push_back(Pair("size_on_disk",          CalculateCurrentUsage()));
     obj.push_back(Pair("pruned",                fPruneMode));
+    if (fPruneMode) {
+        CBlockIndex* block = chainActive.Tip();
+        assert(block);
+        while (block->pprev && (block->pprev->nStatus & BLOCK_HAVE_DATA)) {
+            block = block->pprev;
+        }
+
+        obj.push_back(Pair("pruneheight",        block->nHeight));
+
+        // if 0, execution bypasses the whole if block.
+        bool automatic_pruning = (gArgs.GetArg("-prune", 0) != 1);
+        obj.push_back(Pair("automatic_pruning",  automatic_pruning));
+        if (automatic_pruning) {
+            obj.push_back(Pair("prune_target_size",  nPruneTarget));
+        }
+    }
 
     const Consensus::Params& consensusParams = Params().GetConsensus();
     CBlockIndex* tip = chainActive.Tip();
@@ -1195,14 +1215,6 @@ UniValue getblockchaininfo(const JSONRPCRequest& request)
     obj.push_back(Pair("softforks",             softforks));
     obj.push_back(Pair("bip9_softforks", bip9_softforks));
 
-    if (fPruneMode)
-    {
-        CBlockIndex *block = chainActive.Tip();
-        while (block && block->pprev && (block->pprev->nStatus & BLOCK_HAVE_DATA))
-            block = block->pprev;
-
-        obj.push_back(Pair("pruneheight",        block->nHeight));
-    }
     obj.push_back(Pair("warnings", GetWarnings("statusbar")));
     return obj;
 }

src/validation.cpp

@@ -3233,8 +3233,10 @@ bool TestBlockValidity(CValidationState& state, const CChainParams& chainparams,
  */
 
 /* Calculate the amount of disk space the block & undo files currently use */
-static uint64_t CalculateCurrentUsage()
+uint64_t CalculateCurrentUsage()
 {
+    LOCK(cs_LastBlockFile);
+
     uint64_t retval = 0;
     for (const CBlockFileInfo &file : vinfoBlockFile) {
         retval += file.nSize + file.nUndoSize;
@@ -3245,6 +3247,8 @@ static uint64_t CalculateCurrentUsage()
 /* Prune a block file (modify associated database entries)*/
 void PruneOneBlockFile(const int fileNumber)
 {
+    LOCK(cs_LastBlockFile);
+
     for (BlockMap::iterator it = mapBlockIndex.begin(); it != mapBlockIndex.end(); ++it) {
         CBlockIndex* pindex = it->second;
         if (pindex->nFile == fileNumber) {
@@ -4247,6 +4251,8 @@ std::string CBlockFileInfo::ToString() const
 
 CBlockFileInfo* GetBlockFileInfo(size_t n)
 {
+    LOCK(cs_LastBlockFile);
+
     return &vinfoBlockFile.at(n);
 }
 

src/validation.h

@@ -280,6 +280,9 @@ CAmount GetBlockSubsidy(int nHeight, const Consensus::Params& consensusParams);
 /** Guess verification progress (as a fraction between 0.0=genesis and 1.0=current tip). */
 double GuessVerificationProgress(const ChainTxData& data, CBlockIndex* pindex);
 
+/** Calculate the amount of disk space the block & undo files currently use */
+uint64_t CalculateCurrentUsage();
+
 /**
  *  Mark one block file as pruned.
  */

test/functional/blockchain.py

@@ -24,6 +24,8 @@ import subprocess
 from test_framework.test_framework import BitcoinTestFramework
 from test_framework.util import (
     assert_equal,
+    assert_greater_than,
+    assert_greater_than_or_equal,
     assert_raises,
     assert_raises_jsonrpc,
     assert_is_hex_string,
@@ -58,21 +60,43 @@ class BlockchainTest(BitcoinTestFramework):
             'headers',
             'mediantime',
             'pruned',
+            'size_on_disk',
             'softforks',
             'verificationprogress',
             'warnings',
         ]
         res = self.nodes[0].getblockchaininfo()
-        # result should have pruneheight and default keys if pruning is enabled
-        assert_equal(sorted(res.keys()), sorted(['pruneheight'] + keys))
+
+        # result should have these additional pruning keys if manual pruning is enabled
+        assert_equal(sorted(res.keys()), sorted(['pruneheight', 'automatic_pruning'] + keys))
+
+        # size_on_disk should be > 0
+        assert_greater_than(res['size_on_disk'], 0)
+
         # pruneheight should be greater or equal to 0
-        assert res['pruneheight'] >= 0
+        assert_greater_than_or_equal(res['pruneheight'], 0)
+
+        # check other pruning fields given that prune=1
+        assert res['pruned']
+        assert not res['automatic_pruning']
 
         self.restart_node(0, ['-stopatheight=207'])
         res = self.nodes[0].getblockchaininfo()
         # should have exact keys
         assert_equal(sorted(res.keys()), keys)
 
+        self.restart_node(0, ['-stopatheight=207', '-prune=550'])
+        res = self.nodes[0].getblockchaininfo()
+        # result should have these additional pruning keys if prune=550
+        assert_equal(sorted(res.keys()), sorted(['pruneheight', 'automatic_pruning', 'prune_target_size'] + keys))
+
+        # check related fields
+        assert res['pruned']
+        assert_equal(res['pruneheight'], 0)
+        assert res['automatic_pruning']
+        assert_equal(res['prune_target_size'], 576716800)
+        assert_greater_than(res['size_on_disk'], 0)
+
     def _test_getchaintxstats(self):
         chaintxstats = self.nodes[0].getchaintxstats(1)
         # 200 txs plus genesis tx