Drop the chain argument to GetDifficulty

This removes the need to include rpc/blockchain.cpp in order to put
GetDifficulty under test. GetDifficulty was called in two ways:
* with a guaranteed non-null blockindex
* with no argument

Change the latter case to be provided chainActive.Tip() explicitly.

3 files changed, 7 insertions, 18 deletions

diff --git a/src/rpc/blockchain.cpp b/src/rpc/blockchain.cpp
index 238d8c9d95..5cfc14e89d 100644
--- a/src/rpc/blockchain.cpp
+++ b/src/rpc/blockchain.cpp
@@ -6,7 +6,6 @@
 #include <rpc/blockchain.h>
 
 #include <amount.h>
-#include <chain.h>
 #include <chainparams.h>
 #include <checkpoints.h>
 #include <coins.h>
@@ -47,17 +46,13 @@ static std::mutex cs_blockchange;
 static std::condition_variable cond_blockchange;
 static CUpdatedBlock latestblock;
 
-/* Calculate the difficulty for a given block index,
- * or the block index of the given chain.
+/* Calculate the difficulty for a given block index.
  */
-double GetDifficulty(const CChain& chain, const CBlockIndex* blockindex)
+double GetDifficulty(const CBlockIndex* blockindex)
 {
     if (blockindex == nullptr)
     {
-        if (chain.Tip() == nullptr)
-            return 1.0;
-        else
-            blockindex = chain.Tip();
+        return 1.0;
     }
 
     int nShift = (blockindex->nBits >> 24) & 0xff;
@@ -78,11 +73,6 @@ double GetDifficulty(const CChain& chain, const CBlockIndex* blockindex)
     return dDiff;
 }
 
-double GetDifficulty(const CBlockIndex* blockindex)
-{
-    return GetDifficulty(chainActive, blockindex);
-}
-
 UniValue blockheaderToJSON(const CBlockIndex* blockindex)
 {
     AssertLockHeld(cs_main);
@@ -352,7 +342,7 @@ static UniValue getdifficulty(const JSONRPCRequest& request)
         );
 
     LOCK(cs_main);
-    return GetDifficulty();
+    return GetDifficulty(chainActive.Tip());
 }
 
 static std::string EntryDescriptionString()
@@ -1229,7 +1219,7 @@ UniValue getblockchaininfo(const JSONRPCRequest& request)
     obj.pushKV("blocks",                (int)chainActive.Height());
     obj.pushKV("headers",               pindexBestHeader ? pindexBestHeader->nHeight : -1);
     obj.pushKV("bestblockhash",         chainActive.Tip()->GetBlockHash().GetHex());
-    obj.pushKV("difficulty",            (double)GetDifficulty());
+    obj.pushKV("difficulty",            (double)GetDifficulty(chainActive.Tip()));
     obj.pushKV("mediantime",            (int64_t)chainActive.Tip()->GetMedianTimePast());
     obj.pushKV("verificationprogress",  GuessVerificationProgress(Params().TxData(), chainActive.Tip()));
     obj.pushKV("initialblockdownload",  IsInitialBlockDownload());
diff --git a/src/rpc/blockchain.h b/src/rpc/blockchain.h
index 960edfd56f..3aa8de2d2b 100644
--- a/src/rpc/blockchain.h
+++ b/src/rpc/blockchain.h
@@ -16,7 +16,7 @@ class UniValue;
  * @return A floating point number that is a multiple of the main net minimum
  * difficulty (4295032833 hashes).
  */
-double GetDifficulty(const CBlockIndex* blockindex = nullptr);
+double GetDifficulty(const CBlockIndex* blockindex);
 
 /** Callback for when block tip changed. */
 void RPCNotifyBlockChange(bool ibd, const CBlockIndex *);
@@ -34,4 +34,3 @@ UniValue mempoolToJSON(bool fVerbose = false);
 UniValue blockheaderToJSON(const CBlockIndex* blockindex);
 
 #endif
-
diff --git a/src/rpc/mining.cpp b/src/rpc/mining.cpp
index 203fac39e2..85b864e6b9 100644
--- a/src/rpc/mining.cpp
+++ b/src/rpc/mining.cpp
@@ -214,7 +214,7 @@ static UniValue getmininginfo(const JSONRPCRequest& request)
     obj.pushKV("blocks",           (int)chainActive.Height());
     obj.pushKV("currentblockweight", (uint64_t)nLastBlockWeight);
     obj.pushKV("currentblocktx",   (uint64_t)nLastBlockTx);
-    obj.pushKV("difficulty",       (double)GetDifficulty());
+    obj.pushKV("difficulty",       (double)GetDifficulty(chainActive.Tip()));
     obj.pushKV("networkhashps",    getnetworkhashps(request));
     obj.pushKV("pooledtx",         (uint64_t)mempool.size());
     obj.pushKV("chain",            Params().NetworkIDString());