rpc: add blockchain disk size to getinfo

This should help new nodes predict how much disk space will be
needed for a full sync

src/blockchain_db/blockchain_db.h

@@ -1535,6 +1535,13 @@ public:
    */
   virtual bool is_read_only() const = 0;
 
+  /**
+   * @brief get disk space requirements
+   *
+   * @return the size required
+   */
+  virtual uint64_t get_database_size() const = 0;
+
   // TODO: this should perhaps be (or call) a series of functions which
   // progressively update through version updates
   /**

src/blockchain_db/lmdb/db_lmdb.cpp

@@ -35,6 +35,7 @@
 #include <random>
 
 #include "string_tools.h"
+#include "file_io_utils.h"
 #include "common/util.h"
 #include "cryptonote_basic/cryptonote_format_utils.h"
 #include "crypto/crypto.h"
@@ -3422,6 +3423,16 @@ bool BlockchainLMDB::is_read_only() const
   return false;
 }
 
+uint64_t BlockchainLMDB::get_database_size() const
+{
+  uint64_t size = 0;
+  boost::filesystem::path datafile(m_folder);
+  datafile /= CRYPTONOTE_BLOCKCHAINDATA_FILENAME;
+  if (!epee::file_io_utils::get_file_size(datafile.string(), size))
+    size = 0;
+  return size;
+}
+
 void BlockchainLMDB::fixup()
 {
   LOG_PRINT_L3("BlockchainLMDB::" << __func__);

src/blockchain_db/lmdb/db_lmdb.h

@@ -375,6 +375,8 @@ private:
 
   virtual bool is_read_only() const;
 
+  virtual uint64_t get_database_size() const;
+
   // fix up anything that may be wrong due to past bugs
   virtual void fixup();
 

src/rpc/core_rpc_server.cpp

@@ -207,6 +207,7 @@ namespace cryptonote
       boost::shared_lock<boost::shared_mutex> lock(m_bootstrap_daemon_mutex);
       res.was_bootstrap_ever_used = m_was_bootstrap_ever_used;
     }
+    res.database_size = m_core.get_blockchain_storage().get_db().get_database_size();
     return true;
   }
   //------------------------------------------------------------------------------------------------------------------------------
@@ -1577,6 +1578,7 @@ namespace cryptonote
       boost::shared_lock<boost::shared_mutex> lock(m_bootstrap_daemon_mutex);
       res.was_bootstrap_ever_used = m_was_bootstrap_ever_used;
     }
+    res.database_size = m_core.get_blockchain_storage().get_db().get_database_size();
     return true;
   }
   //------------------------------------------------------------------------------------------------------------------------------

src/rpc/core_rpc_server_commands_defs.h

@@ -49,7 +49,7 @@ namespace cryptonote
 // advance which version they will stop working with
 // Don't go over 32767 for any of these
 #define CORE_RPC_VERSION_MAJOR 1
-#define CORE_RPC_VERSION_MINOR 20
+#define CORE_RPC_VERSION_MINOR 21
 #define MAKE_CORE_RPC_VERSION(major,minor) (((major)<<16)|(minor))
 #define CORE_RPC_VERSION MAKE_CORE_RPC_VERSION(CORE_RPC_VERSION_MAJOR, CORE_RPC_VERSION_MINOR)
 
@@ -964,6 +964,7 @@ namespace cryptonote
       std::string bootstrap_daemon_address;
       uint64_t height_without_bootstrap;
       bool was_bootstrap_ever_used;
+      uint64_t database_size;
 
       BEGIN_KV_SERIALIZE_MAP()
         KV_SERIALIZE(status)
@@ -993,6 +994,7 @@ namespace cryptonote
         KV_SERIALIZE(bootstrap_daemon_address)
         KV_SERIALIZE(height_without_bootstrap)
         KV_SERIALIZE(was_bootstrap_ever_used)
+        KV_SERIALIZE(database_size)
       END_KV_SERIALIZE_MAP()
     };
   };

tests/unit_tests/hardfork.cpp

@@ -124,6 +124,7 @@ public:
   virtual void remove_txpool_tx(const crypto::hash& txid) {}
   virtual bool get_txpool_tx_meta(const crypto::hash& txid, txpool_tx_meta_t &meta) const { return false; }
   virtual bool get_txpool_tx_blob(const crypto::hash& txid, cryptonote::blobdata &bd) const { return false; }
+  virtual uint64_t get_database_size() const { return 0; }
   virtual cryptonote::blobdata get_txpool_tx_blob(const crypto::hash& txid) const { return ""; }
   virtual bool for_all_txpool_txes(std::function<bool(const crypto::hash&, const txpool_tx_meta_t&, const cryptonote::blobdata*)>, bool include_blob = false, bool include_unrelayed_txes = false) const { return false; }