Trivial: Fix validation comments

- Move comment about transaction/block weight calculation so it applies not only to the GetBlockWeight function but also to GetTransactionWeight
- Fix comment in validation.cpp referencing future deployment of BIP113. It has already been deployed.
- The doc comment for BLOCK_DOWNLOAD_WINDOW wasn't updated since pruning was introduced, so it still refers to pruning as something that might happen in the future. A larger BLOCK_DOWNLOAD_WINDOW window would now, indeed, make pruning harder.

src/consensus/validation.h

@@ -89,17 +89,16 @@ public:
     std::string GetDebugMessage() const { return strDebugMessage; }
 };
 
+// These implement the weight = (stripped_size * 4) + witness_size formula,
+// using only serialization with and without witness data. As witness_size
+// is equal to total_size - stripped_size, this formula is identical to:
+// weight = (stripped_size * 3) + total_size.
 static inline int64_t GetTransactionWeight(const CTransaction& tx)
 {
     return ::GetSerializeSize(tx, SER_NETWORK, PROTOCOL_VERSION | SERIALIZE_TRANSACTION_NO_WITNESS) * (WITNESS_SCALE_FACTOR - 1) + ::GetSerializeSize(tx, SER_NETWORK, PROTOCOL_VERSION);
 }
-
 static inline int64_t GetBlockWeight(const CBlock& block)
 {
-    // This implements the weight = (stripped_size * 4) + witness_size formula,
-    // using only serialization with and without witness data. As witness_size
-    // is equal to total_size - stripped_size, this formula is identical to:
-    // weight = (stripped_size * 3) + total_size.
     return ::GetSerializeSize(block, SER_NETWORK, PROTOCOL_VERSION | SERIALIZE_TRANSACTION_NO_WITNESS) * (WITNESS_SCALE_FACTOR - 1) + ::GetSerializeSize(block, SER_NETWORK, PROTOCOL_VERSION);
 }
 

src/validation.cpp

@@ -219,7 +219,7 @@ bool CheckFinalTx(const CTransaction &tx, int flags)
     // IsFinalTx() with one more than chainActive.Height().
     const int nBlockHeight = chainActive.Height() + 1;
 
-    // BIP113 will require that time-locked transactions have nLockTime set to
+    // BIP113 requires that time-locked transactions have nLockTime set to
     // less than the median time of the previous block they're contained in.
     // When the next block is created its previous block will be the current
     // chain tip, so we use that to calculate the median time passed to

src/validation.h

@@ -94,8 +94,8 @@ static const int MAX_CMPCTBLOCK_DEPTH = 5;
 static const int MAX_BLOCKTXN_DEPTH = 10;
 /** Size of the "block download window": how far ahead of our current height do we fetch?
  *  Larger windows tolerate larger download speed differences between peer, but increase the potential
- *  degree of disordering of blocks on disk (which make reindexing and in the future perhaps pruning
+ *  degree of disordering of blocks on disk (which make reindexing and pruning harder). We'll probably
- *  harder). We'll probably want to make this a per-peer adaptive value at some point. */
+ *  want to make this a per-peer adaptive value at some point. */
 static const unsigned int BLOCK_DOWNLOAD_WINDOW = 1024;
 /** Time to wait (in seconds) between writing blocks/block index to disk. */
 static const unsigned int DATABASE_WRITE_INTERVAL = 60 * 60;