blockchain_import: Add mode argument representing multiple DB flags

These modes match those optionally provided as part of the daemon's
--db-type argument.

Argument after the # is interpreted as a composite mode if there's only
one (no comma separated arguments).

Sample usage:

blockchain_import --database lmdb#fastest

blockchain_import --database berkeley#fastest

Multiple specific DB flags are still supported, e.g.

blockchain_import --database lmdb#nosync,nordahead

blockchain_import --database berkeley#txn_nosync

src/blockchain_utilities/blockchain_import.cpp

@@ -78,6 +78,31 @@ using namespace cryptonote;
 using namespace epee;
 
 
+// db_type: lmdb, berkeley
+// db_mode: safe, fast, fastest
+int get_db_flags_from_mode(const std::string& db_type, const std::string& db_mode)
+{
+  uint64_t BDB_FAST_MODE = 0;
+  uint64_t BDB_FASTEST_MODE = 0;
+  uint64_t BDB_SAFE_MODE = 0;
+
+#if defined(BERKELEY_DB)
+  BDB_FAST_MODE = DB_TXN_WRITE_NOSYNC;
+  BDB_FASTEST_MODE = DB_TXN_NOSYNC;
+  BDB_SAFE_MODE = DB_TXN_SYNC;
+#endif
+
+  int db_flags = 0;
+  bool islmdb = db_type == "lmdb";
+  if (db_mode == "safe")
+    db_flags = islmdb ? MDB_NORDAHEAD : BDB_SAFE_MODE;
+  else if (db_mode == "fast")
+    db_flags = islmdb ? MDB_NOMETASYNC | MDB_NOSYNC | MDB_NORDAHEAD : BDB_FAST_MODE;
+  else if (db_mode == "fastest")
+    db_flags = islmdb ? MDB_WRITEMAP | MDB_MAPASYNC | MDB_NORDAHEAD | MDB_NOMETASYNC | MDB_NOSYNC : BDB_FASTEST_MODE;
+  return db_flags;
+}
+
 int parse_db_arguments(const std::string& db_arg_str, std::string& db_type, int& db_flags)
 {
   std::vector<std::string> db_args;
@@ -95,45 +120,71 @@ int parse_db_arguments(const std::string& db_arg_str, std::string& db_type, int&
     return 1;
   }
 
+#if !defined(BERKELEY_DB)
+  if (db_type == "berkeley")
+  {
+    LOG_ERROR("BerkeleyDB support disabled.");
+    return false;
+  }
+#endif
+
   std::string db_arg_str2 = db_args[1];
   boost::split(db_args, db_arg_str2, boost::is_any_of(","));
-  for (auto& it : db_args)
+
+  // optionally use a composite mode instead of individual flags
+  const std::unordered_set<std::string> db_modes {"safe", "fast", "fastest"};
+  std::string db_mode;
+  if (db_args.size() == 1)
   {
-    boost::algorithm::trim(it);
-    if (it.empty())
-      continue;
-    if (db_type == "lmdb")
+    if (db_modes.count(db_args[0]) > 0)
+    {
+      db_mode = db_args[0];
+    }
+  }
+  if (! db_mode.empty())
+  {
+    db_flags = get_db_flags_from_mode(db_type, db_mode);
+  }
+  else
+  {
+    for (auto& it : db_args)
     {
-      LOG_PRINT_L1("LMDB flag: " << it);
-      if (it == "nosync")
-        db_flags |= MDB_NOSYNC;
-      else if (it == "nometasync")
-        db_flags |= MDB_NOMETASYNC;
-      else if (it == "writemap")
-        db_flags |= MDB_WRITEMAP;
-      else if (it == "mapasync")
-        db_flags |= MDB_MAPASYNC;
-      else if (it == "nordahead")
-        db_flags |= MDB_NORDAHEAD;
-      else
+      boost::algorithm::trim(it);
+      if (it.empty())
+	continue;
+      if (db_type == "lmdb")
       {
-        std::cerr << "unrecognized database flag: " << it << ENDL;
-        return 1;
+	LOG_PRINT_L1("LMDB flag: " << it);
+	if (it == "nosync")
+	  db_flags |= MDB_NOSYNC;
+	else if (it == "nometasync")
+	  db_flags |= MDB_NOMETASYNC;
+	else if (it == "writemap")
+	  db_flags |= MDB_WRITEMAP;
+	else if (it == "mapasync")
+	  db_flags |= MDB_MAPASYNC;
+	else if (it == "nordahead")
+	  db_flags |= MDB_NORDAHEAD;
+	else
+	{
+	  std::cerr << "unrecognized database flag: " << it << ENDL;
+	  return 1;
+	}
       }
-    }
 #if defined(BERKELEY_DB)
-    else if (db_type == "berkeley")
-    {
-      if (it == "txn_write_nosync")
-        db_flags = DB_TXN_WRITE_NOSYNC;
-      else if (it == "txn_nosync")
-        db_flags = DB_TXN_NOSYNC;
-      else if (it == "txn_sync")
-        db_flags = DB_TXN_SYNC;
-      else
+      else if (db_type == "berkeley")
       {
-        std::cerr << "unrecognized database flag: " << it << ENDL;
-        return 1;
+	if (it == "txn_write_nosync")
+	  db_flags = DB_TXN_WRITE_NOSYNC;
+	else if (it == "txn_nosync")
+	  db_flags = DB_TXN_NOSYNC;
+	else if (it == "txn_sync")
+	  db_flags = DB_TXN_SYNC;
+	else
+	{
+	  std::cerr << "unrecognized database flag: " << it << ENDL;
+	  return 1;
+	}
       }
 #endif
     }