Add time helpers

To be used in the next commit

src/chain.h

@@ -12,6 +12,7 @@
 #include <primitives/block.h>
 #include <sync.h>
 #include <uint256.h>
+#include <util/time.h>
 
 #include <vector>
 
@@ -275,6 +276,11 @@ public:
      */
     bool HaveTxsDownloaded() const { return nChainTx != 0; }
 
+    NodeSeconds Time() const
+    {
+        return NodeSeconds{std::chrono::seconds{nTime}};
+    }
+
     int64_t GetBlockTime() const
     {
         return (int64_t)nTime;

src/consensus/params.h

@@ -8,6 +8,7 @@
 
 #include <uint256.h>
 
+#include <chrono>
 #include <limits>
 #include <map>
 
@@ -109,6 +110,10 @@ struct Params {
     bool fPowNoRetargeting;
     int64_t nPowTargetSpacing;
     int64_t nPowTargetTimespan;
+    std::chrono::seconds PowTargetSpacing() const
+    {
+        return std::chrono::seconds{nPowTargetSpacing};
+    }
     int64_t DifficultyAdjustmentInterval() const { return nPowTargetTimespan / nPowTargetSpacing; }
     /** The best chain should have at least this much work */
     uint256 nMinimumChainWork;

src/primitives/block.h

@@ -9,6 +9,7 @@
 #include <primitives/transaction.h>
 #include <serialize.h>
 #include <uint256.h>
+#include <util/time.h>
 
 /** Nodes collect new transactions into a block, hash them into a hash tree,
  * and scan through nonce values to make the block's hash satisfy proof-of-work
@@ -52,6 +53,11 @@ public:
 
     uint256 GetHash() const;
 
+    NodeSeconds Time() const
+    {
+        return NodeSeconds{std::chrono::seconds{nTime}};
+    }
+
     int64_t GetBlockTime() const
     {
         return (int64_t)nTime;