Cover UTXO set access with lock annotations

i.e. any CoinsViews members. Adds a lock acquisition to `gettxoutsetinfo` RPC
to comply with added annotations.

Co-authored-by: Russell Yanofsky <russ@yanofsky.org>

src/validation.h

@@ -519,14 +519,14 @@ class CoinsViews {
 public:
     //! The lowest level of the CoinsViews cache hierarchy sits in a leveldb database on disk.
     //! All unspent coins reside in this store.
-    CCoinsViewDB m_dbview;
+    CCoinsViewDB m_dbview GUARDED_BY(cs_main);
 
     //! This view wraps access to the leveldb instance and handles read errors gracefully.
-    CCoinsViewErrorCatcher m_catcherview;
+    CCoinsViewErrorCatcher m_catcherview GUARDED_BY(cs_main);
 
     //! This is the top layer of the cache hierarchy - it keeps as many coins in memory as
     //! can fit per the dbcache setting.
-    std::unique_ptr<CCoinsViewCache> m_cacheview;
+    std::unique_ptr<CCoinsViewCache> m_cacheview GUARDED_BY(cs_main);
 
     //! This constructor initializes CCoinsViewDB and CCoinsViewErrorCatcher instances, but it
     //! *does not* create a CCoinsViewCache instance by default. This is done separately because the
@@ -537,7 +537,7 @@ public:
     CoinsViews(std::string ldb_name, size_t cache_size_bytes, bool in_memory, bool should_wipe);
 
     //! Initialize the CCoinsViewCache member.
-    void InitCache();
+    void InitCache() EXCLUSIVE_LOCKS_REQUIRED(::cs_main);
 };
 
 /**
@@ -609,11 +609,11 @@ public:
 
     //! Initialize the in-memory coins cache (to be done after the health of the on-disk database
     //! is verified).
-    void InitCoinsCache();
+    void InitCoinsCache() EXCLUSIVE_LOCKS_REQUIRED(::cs_main);
 
     //! @returns whether or not the CoinsViews object has been fully initialized and we can
     //!          safely flush this object to disk.
-    bool CanFlushToDisk() {
+    bool CanFlushToDisk() EXCLUSIVE_LOCKS_REQUIRED(cs_main) {
         return m_coins_views && m_coins_views->m_cacheview;
     }
 
@@ -629,21 +629,21 @@ public:
     std::set<CBlockIndex*, CBlockIndexWorkComparator> setBlockIndexCandidates;
 
     //! @returns A reference to the in-memory cache of the UTXO set.
-    CCoinsViewCache& CoinsTip()
+    CCoinsViewCache& CoinsTip() EXCLUSIVE_LOCKS_REQUIRED(cs_main)
     {
         assert(m_coins_views->m_cacheview);
         return *m_coins_views->m_cacheview.get();
     }
 
     //! @returns A reference to the on-disk UTXO set database.
-    CCoinsViewDB& CoinsDB()
+    CCoinsViewDB& CoinsDB() EXCLUSIVE_LOCKS_REQUIRED(cs_main)
     {
         return m_coins_views->m_dbview;
     }
 
     //! @returns A reference to a wrapped view of the in-memory UTXO set that
     //!     handles disk read errors gracefully.
-    CCoinsViewErrorCatcher& CoinsErrorCatcher()
+    CCoinsViewErrorCatcher& CoinsErrorCatcher() EXCLUSIVE_LOCKS_REQUIRED(cs_main)
     {
         return m_coins_views->m_catcherview;
     }