Move ParseConfirmTarget from rpc/mining to rpc/util

Util is a better home since it's called both by wallet and mining code.

Suggested bitcoin/bitcoin#15288 (comment)

Author: ryanofsky

src/rpc/mining.cpp

@@ -31,16 +31,6 @@
 #include <memory>
 #include <stdint.h>
 
-unsigned int ParseConfirmTarget(const UniValue& value)
-{
-    int target = value.get_int();
-    unsigned int max_target = ::feeEstimator.HighestTargetTracked(FeeEstimateHorizon::LONG_HALFLIFE);
-    if (target < 1 || (unsigned int)target > max_target) {
-        throw JSONRPCError(RPC_INVALID_PARAMETER, strprintf("Invalid conf_target, must be between %u - %u", 1, max_target));
-    }
-    return (unsigned int)target;
-}
-
 /**
  * Return average network hashes per second based on the last 'lookup' blocks,
  * or from the last difficulty change if 'lookup' is nonpositive.

src/rpc/mining.h

@@ -12,7 +12,4 @@
 /** Generate blocks (mine) */
 UniValue generateBlocks(std::shared_ptr<CReserveScript> coinbaseScript, int nGenerate, uint64_t nMaxTries, bool keepScript);
 
-/** Check bounds on a command line confirm target */
-unsigned int ParseConfirmTarget(const UniValue& value);
-
 #endif

src/rpc/util.cpp

@@ -4,10 +4,12 @@
 
 #include <key_io.h>
 #include <keystore.h>
+#include <policy/fees.h>
 #include <rpc/protocol.h>
 #include <rpc/util.h>
 #include <tinyformat.h>
 #include <util/strencodings.h>
+#include <validation.h>
 
 InitInterfaces* g_rpc_interfaces = nullptr;
 
@@ -129,6 +131,16 @@ UniValue DescribeAddress(const CTxDestination& dest)
     return boost::apply_visitor(DescribeAddressVisitor(), dest);
 }
 
+unsigned int ParseConfirmTarget(const UniValue& value)
+{
+    int target = value.get_int();
+    unsigned int max_target = ::feeEstimator.HighestTargetTracked(FeeEstimateHorizon::LONG_HALFLIFE);
+    if (target < 1 || (unsigned int)target > max_target) {
+        throw JSONRPCError(RPC_INVALID_PARAMETER, strprintf("Invalid conf_target, must be between %u - %u", 1, max_target));
+    }
+    return (unsigned int)target;
+}
+
 struct Section {
     Section(const std::string& left, const std::string& right)
         : m_left{left}, m_right{right} {}

src/rpc/util.h

@@ -28,6 +28,9 @@ CScript CreateMultisigRedeemscript(const int required, const std::vector<CPubKey
 
 UniValue DescribeAddress(const CTxDestination& dest);
 
+//! Parse a confirm target option and raise an RPC error if it is invalid.
+unsigned int ParseConfirmTarget(const UniValue& value);
+
 struct RPCArg {
     enum class Type {
         OBJ,