Merge #16443: refactor: have CCoins* data managed under CChainState

582d2cd74754d6b9a2394616a9c82a89d2d71976 Cover UTXO set access with lock annotations (James O'Beirne)
569353068568444a25b301bbd6513bb510157dc9 refactor: have CCoins* data managed under CChainState (James O'Beirne)
fae6ab6aed3b9fdc9201bb19a307dfc3d9b89891 refactor: pcoinsTip -> CChainState::CoinsTip() (James O'Beirne)

Pull request description:

  This is part of the [assumeutxo project](https://github.com/bitcoin/bitcoin/projects/11):

  Parent PR: #15606
  Issue: #15605
  Specification: https://github.com/jamesob/assumeutxo-docs/tree/2019-04-proposal/proposal

  ---

  This change encapsulates UTXO set data within CChainState instances, removing global data `pcoinsTip` and `pcoinsviewdb`. This is necessary if we want to maintain multiple chainstates with their own rendering of the UTXO set.

  We introduce a class CoinsViews which consolidates the construction of a CCoins* hierarchy.

  This commit could be broken into smaller pieces, but it would require more ephemeral diffs to, e.g., temporarily change CCoinsViewDB's constructor invocations.

ACKs for top commit:
  Sjors:
    reACK 582d2cd74754d6b9a2394616a9c82a89d2d71976
  MarcoFalke:
    ACK 582d2cd747

Tree-SHA512: ec9d904fe5dca8cd2dc4b7916daa5d8bab30856dd4645987300f905e0a19f9919fce4f9d1ff03eda982943ca73e6e9a746be6cf53b46510de36e8c81a1eafba1

2 files changed, 14 insertions, 9 deletions

diff --git a/src/rpc/blockchain.cpp b/src/rpc/blockchain.cpp
index b7dcd59c6d..e3d5394a2c 100644
--- a/src/rpc/blockchain.cpp
+++ b/src/rpc/blockchain.cpp
@@ -1062,7 +1062,9 @@ static UniValue gettxoutsetinfo(const JSONRPCRequest& request)
 
     CCoinsStats stats;
     ::ChainstateActive().ForceFlushStateToDisk();
-    if (GetUTXOStats(pcoinsdbview.get(), stats)) {
+
+    CCoinsView* coins_view = WITH_LOCK(cs_main, return &ChainstateActive().CoinsDB());
+    if (GetUTXOStats(coins_view, stats)) {
         ret.pushKV("height", (int64_t)stats.nHeight);
         ret.pushKV("bestblock", stats.hashBlock.GetHex());
         ret.pushKV("transactions", (int64_t)stats.nTransactions);
@@ -1126,19 +1128,21 @@ UniValue gettxout(const JSONRPCRequest& request)
         fMempool = request.params[2].get_bool();
 
     Coin coin;
+    CCoinsViewCache* coins_view = &::ChainstateActive().CoinsTip();
+
     if (fMempool) {
         LOCK(mempool.cs);
-        CCoinsViewMemPool view(pcoinsTip.get(), mempool);
+        CCoinsViewMemPool view(coins_view, mempool);
         if (!view.GetCoin(out, coin) || mempool.isSpent(out)) {
             return NullUniValue;
         }
     } else {
-        if (!pcoinsTip->GetCoin(out, coin)) {
+        if (!coins_view->GetCoin(out, coin)) {
             return NullUniValue;
         }
     }
 
-    const CBlockIndex* pindex = LookupBlockIndex(pcoinsTip->GetBestBlock());
+    const CBlockIndex* pindex = LookupBlockIndex(coins_view->GetBestBlock());
     ret.pushKV("bestblock", pindex->GetBlockHash().GetHex());
     if (coin.nHeight == MEMPOOL_HEIGHT) {
         ret.pushKV("confirmations", 0);
@@ -1180,7 +1184,8 @@ static UniValue verifychain(const JSONRPCRequest& request)
     if (!request.params[1].isNull())
         nCheckDepth = request.params[1].get_int();
 
-    return CVerifyDB().VerifyDB(Params(), pcoinsTip.get(), nCheckLevel, nCheckDepth);
+    return CVerifyDB().VerifyDB(
+        Params(), &::ChainstateActive().CoinsTip(), nCheckLevel, nCheckDepth);
 }
 
 /** Implementation of IsSuperMajority with better feedback */
@@ -2203,7 +2208,7 @@ UniValue scantxoutset(const JSONRPCRequest& request)
         {
             LOCK(cs_main);
             ::ChainstateActive().ForceFlushStateToDisk();
-            pcursor = std::unique_ptr<CCoinsViewCursor>(pcoinsdbview->Cursor());
+            pcursor = std::unique_ptr<CCoinsViewCursor>(::ChainstateActive().CoinsDB().Cursor());
             assert(pcursor);
         }
         bool res = FindScriptPubKey(g_scan_progress, g_should_abort_scan, count, pcursor.get(), needles, coins);
diff --git a/src/rpc/rawtransaction.cpp b/src/rpc/rawtransaction.cpp
index 966c159f0f..ffbad45714 100644
--- a/src/rpc/rawtransaction.cpp
+++ b/src/rpc/rawtransaction.cpp
@@ -259,7 +259,7 @@ static UniValue gettxoutproof(const JSONRPCRequest& request)
 
         // Loop through txids and try to find which block they're in. Exit loop once a block is found.
         for (const auto& tx : setTxids) {
-            const Coin& coin = AccessByTxid(*pcoinsTip, tx);
+            const Coin& coin = AccessByTxid(::ChainstateActive().CoinsTip(), tx);
             if (!coin.IsSpent()) {
                 pblockindex = ::ChainActive()[coin.nHeight];
                 break;
@@ -636,7 +636,7 @@ static UniValue combinerawtransaction(const JSONRPCRequest& request)
     {
         LOCK(cs_main);
         LOCK(mempool.cs);
-        CCoinsViewCache &viewChain = *pcoinsTip;
+        CCoinsViewCache &viewChain = ::ChainstateActive().CoinsTip();
         CCoinsViewMemPool viewMempool(&viewChain, mempool);
         view.SetBackend(viewMempool); // temporarily switch cache backend to db+mempool view
 
@@ -1505,7 +1505,7 @@ UniValue utxoupdatepsbt(const JSONRPCRequest& request)
     CCoinsViewCache view(&viewDummy);
     {
         LOCK2(cs_main, mempool.cs);
-        CCoinsViewCache &viewChain = *pcoinsTip;
+        CCoinsViewCache &viewChain = ::ChainstateActive().CoinsTip();
         CCoinsViewMemPool viewMempool(&viewChain, mempool);
         view.SetBackend(viewMempool); // temporarily switch cache backend to db+mempool view