Remove some unnecessary c_strs() in logging and the GUI

Includes `core: remove unneeded c_str() / Qt: replace c_str() with Qt code`
by P. Kaufmann.

src/addrman.h

@@ -424,7 +424,7 @@ public:
             Check();
         }
         if (fRet)
-            LogPrint("addrman", "Added %s from %s: %i tried, %i new\n", addr.ToStringIPPort().c_str(), source.ToString(), nTried, nNew);
+            LogPrint("addrman", "Added %s from %s: %i tried, %i new\n", addr.ToStringIPPort(), source.ToString(), nTried, nNew);
         return fRet;
     }
 

src/main.cpp

@@ -4392,7 +4392,7 @@ bool SendMessages(CNode* pto, bool fSendTrickle)
         if (!pto->fDisconnect && state.nBlocksInFlight &&
             state.nLastBlockReceive < state.nLastBlockProcess - BLOCK_DOWNLOAD_TIMEOUT*1000000 &&
             state.vBlocksInFlight.front().nTime < state.nLastBlockProcess - 2*BLOCK_DOWNLOAD_TIMEOUT*1000000) {
-            LogPrintf("Peer %s is stalling block download, disconnecting\n", state.name.c_str());
+            LogPrintf("Peer %s is stalling block download, disconnecting\n", state.name);
             pto->fDisconnect = true;
         }
 
@@ -4502,7 +4502,7 @@ bool CBlockUndo::ReadFromDisk(const CDiskBlockPos &pos, const uint256 &hashBlock
 }
 
  std::string CBlockFileInfo::ToString() const {
-     return strprintf("CBlockFileInfo(blocks=%u, size=%u, heights=%u...%u, time=%s...%s)", nBlocks, nSize, nHeightFirst, nHeightLast, DateTimeStrFormat("%Y-%m-%d", nTimeFirst).c_str(), DateTimeStrFormat("%Y-%m-%d", nTimeLast).c_str());
+     return strprintf("CBlockFileInfo(blocks=%u, size=%u, heights=%u...%u, time=%s...%s)", nBlocks, nSize, nHeightFirst, nHeightLast, DateTimeStrFormat("%Y-%m-%d", nTimeFirst), DateTimeStrFormat("%Y-%m-%d", nTimeLast));
  }
 
 

src/net.cpp

@@ -2114,7 +2114,7 @@ void CNode::AskFor(const CInv& inv)
         nRequestTime = it->second;
     else
         nRequestTime = 0;
-    LogPrint("net", "askfor %s  %d (%s) peer=%d\n", inv.ToString(), nRequestTime, DateTimeStrFormat("%H:%M:%S", nRequestTime/1000000).c_str(), id);
+    LogPrint("net", "askfor %s  %d (%s) peer=%d\n", inv.ToString(), nRequestTime, DateTimeStrFormat("%H:%M:%S", nRequestTime/1000000), id);
 
     // Make sure not to reuse time indexes to keep things in the same order
     int64_t nNow = GetTimeMicros() - 1000000;

src/qt/coincontroldialog.cpp

@@ -705,7 +705,7 @@ void CoinControlDialog::updateView()
             QString sAddress = "";
             if(ExtractDestination(out.tx->vout[out.i].scriptPubKey, outputAddress))
             {
-                sAddress = CBitcoinAddress(outputAddress).ToString().c_str();
+                sAddress = QString::fromStdString(CBitcoinAddress(outputAddress).ToString());
 
                 // if listMode or change => show bitcoin address. In tree mode, address is not shown again for direct wallet address outputs
                 if (!treeMode || (!(sAddress == sWalletAddress)))
@@ -752,7 +752,7 @@ void CoinControlDialog::updateView()
 
             // transaction hash
             uint256 txhash = out.tx->GetHash();
-            itemOutput->setText(COLUMN_TXHASH, txhash.GetHex().c_str());
+            itemOutput->setText(COLUMN_TXHASH, QString::fromStdString(txhash.GetHex()));
 
             // vout index
             itemOutput->setText(COLUMN_VOUT_INDEX, QString::number(out.i));

src/qt/walletmodel.cpp

@@ -622,7 +622,7 @@ void WalletModel::listCoins(std::map<QString, std::vector<COutput> >& mapCoins)
         CTxDestination address;
         if(!out.fSpendable || !ExtractDestination(cout.tx->vout[cout.i].scriptPubKey, address))
             continue;
-        mapCoins[CBitcoinAddress(address).ToString().c_str()].push_back(out);
+        mapCoins[QString::fromStdString(CBitcoinAddress(address).ToString())].push_back(out);
     }
 }
 

src/txmempool.cpp

@@ -606,7 +606,7 @@ void CTxMemPool::PrioritiseTransaction(const uint256 hash, const string strHash,
         deltas.first += dPriorityDelta;
         deltas.second += nFeeDelta;
     }
-    LogPrintf("PrioritiseTransaction: %s priority += %f, fee += %d\n", strHash.c_str(), dPriorityDelta, nFeeDelta);
+    LogPrintf("PrioritiseTransaction: %s priority += %f, fee += %d\n", strHash, dPriorityDelta, nFeeDelta);
 }
 
 void CTxMemPool::ApplyDeltas(const uint256 hash, double &dPriorityDelta, int64_t &nFeeDelta)

src/wallet.cpp

@@ -42,7 +42,7 @@ struct CompareValueOnly
 
 std::string COutput::ToString() const
 {
-    return strprintf("COutput(%s, %d, %d) [%s]", tx->GetHash().ToString(), i, nDepth, FormatMoney(tx->vout[i].nValue).c_str());
+    return strprintf("COutput(%s, %d, %d) [%s]", tx->GetHash().ToString(), i, nDepth, FormatMoney(tx->vout[i].nValue));
 }
 
 const CWalletTx* CWallet::GetWalletTx(const uint256& hash) const