wallet: Replace CDataStream& with CDataStream&& where appropriate

The keys and values are only to be used once because their memory is set
to zero. Make that explicit by moving the bytes into the lower level
methods.

Author: MarcoFalke

src/wallet/bdb.cpp

@@ -796,7 +796,7 @@ std::string BerkeleyDatabaseVersion()
     return DbEnv::version(nullptr, nullptr, nullptr);
 }
 
-bool BerkeleyBatch::ReadKey(CDataStream& key, CDataStream& value)
+bool BerkeleyBatch::ReadKey(CDataStream&& key, CDataStream& value)
 {
     if (!pdb)
         return false;
@@ -812,7 +812,7 @@ bool BerkeleyBatch::ReadKey(CDataStream& key, CDataStream& value)
     return false;
 }
 
-bool BerkeleyBatch::WriteKey(CDataStream& key, CDataStream& value, bool overwrite)
+bool BerkeleyBatch::WriteKey(CDataStream&& key, CDataStream&& value, bool overwrite)
 {
     if (!pdb)
         return true;
@@ -827,7 +827,7 @@ bool BerkeleyBatch::WriteKey(CDataStream& key, CDataStream& value, bool overwrit
     return (ret == 0);
 }
 
-bool BerkeleyBatch::EraseKey(CDataStream& key)
+bool BerkeleyBatch::EraseKey(CDataStream&& key)
 {
     if (!pdb)
         return false;
@@ -840,7 +840,7 @@ bool BerkeleyBatch::EraseKey(CDataStream& key)
     return (ret == 0 || ret == DB_NOTFOUND);
 }
 
-bool BerkeleyBatch::HasKey(CDataStream& key)
+bool BerkeleyBatch::HasKey(CDataStream&& key)
 {
     if (!pdb)
         return false;

src/wallet/bdb.h

@@ -195,10 +195,10 @@ class BerkeleyBatch
     };
 
 private:
-    bool ReadKey(CDataStream& key, CDataStream& value);
-    bool WriteKey(CDataStream& key, CDataStream& value, bool overwrite=true);
-    bool EraseKey(CDataStream& key);
-    bool HasKey(CDataStream& key);
+    bool ReadKey(CDataStream&& key, CDataStream& value);
+    bool WriteKey(CDataStream&& key, CDataStream&& value, bool overwrite = true);
+    bool EraseKey(CDataStream&& key);
+    bool HasKey(CDataStream&& key);
 
 protected:
     Db* pdb;
@@ -227,7 +227,7 @@ class BerkeleyBatch
         ssKey << key;
 
         CDataStream ssValue(SER_DISK, CLIENT_VERSION);
-        if (!ReadKey(ssKey, ssValue)) return false;
+        if (!ReadKey(std::move(ssKey), ssValue)) return false;
         try {
             ssValue >> value;
             return true;
@@ -247,7 +247,7 @@ class BerkeleyBatch
         ssValue.reserve(10000);
         ssValue << value;
 
-        return WriteKey(ssKey, ssValue, fOverwrite);
+        return WriteKey(std::move(ssKey), std::move(ssValue), fOverwrite);
     }
 
     template <typename K>
@@ -257,7 +257,7 @@ class BerkeleyBatch
         ssKey.reserve(1000);
         ssKey << key;
 
-        return EraseKey(ssKey);
+        return EraseKey(std::move(ssKey));
     }
 
     template <typename K>
@@ -267,7 +267,7 @@ class BerkeleyBatch
         ssKey.reserve(1000);
         ssKey << key;
 
-        return HasKey(ssKey);
+        return HasKey(std::move(ssKey));
     }
 
     bool StartCursor();