FLO_getbalance_notes.md

FLO_getbalance_notes.md

GetBalance RPC command research notes

Main function defined in wallet.cpp

GetBalance() is defined in wallet.cpp:

CAmount CWallet::GetBalance() const 
{
    CAmount nTotal = 0;
    {
        LOCK2(cs_main, cs_wallet);
        for (const auto& entry : mapWallet)
        {
            const CWalletTx* pcoin = &entry.second;
            if (pcoin->IsTrusted())
                nTotal += pcoin->GetAvailableCredit();
        }
    }

    return nTotal;
}

Overview of GetBalance() function

Steps taken in this method:

1. Begin function setting up temporary variables

• Set nTotal to 0 first, we will later use nTotal to sum up coins
• Start a new code block
• Lock cs_main and cs_wallet

2. Iterate through mapWallet: for (const auto& entry : mapWallet)

• auto& automatically converts entry to whatever type the members of mapWallet are (?)
• mapWallet is defined in wallet.h as a mapping of uint256 to CWalletTx. Therefore, entry is a single pair of the mapping <uint256, CWalletTx>
• More detailed information on mapWallet below

3. For each <uint256, CWalletTx> pair in mapWallet do the following:

• Create a pointer to the CWalletTx in that pair: const CWalletTx* pcoin = &entry.second;
• if (pcoin->IsTrusted() then add pcoin->GetAvailableCredit() to nTotal

@defgroup mapWallet
 *
 * @{
 */

(?)

mapWallet defined in wallet.h:

    std::map<uint256, CWalletTx> mapWallet;

it's a mapping of uint256 (the transaction hash) to CWalletTx (the class used to store Wallet Transactions)

from the definition of class CWalletTx:

 * A transaction with a bunch of additional info that only the owner cares about.
 * It includes any unrecorded transactions needed to link it back to the block chain.

CWalletTx has various balances each with a cache and a mutable amount:

• Debit
• Credit
• Immature
• Available
• Change
• Watch-only (not relevant to our examination)

There are also various

GetAvailableCredit in wallet.cpp

GetAvailableCredit() caches the available credit when it's called. It's called from these functions:

• GetBalance() which is called by:
  • GetCredit(const isminefilter& filter) which is called by:

    • UniValue gettransaction() from rpcwallet.cpp which is called by the RPC only

    • decomeposeTransaction) in transactionrecord.cpp which is called by:

      • refreshWallet() which is a member function of class TransactionTablePriv called by:
        • TransactionTableModel constructor which is called:
        • Any time a TransactionTablePriv is constructed
      • updateWallet() which is a member function of class TransactionTablePriv

        • TransactionTableModel::updateTransaction which is called by:

    • GetAvailableCredit() (recursive?) (?)

    • GetImmatureWatchOnlyCredit() which is called by:

    • GetAvailableWatchOnlyCredit() which is called by:

    • GetImmatureCredit() which is called by:

• GetUnconfirmedBalance() which is called by:

Other Notes and Ideas

COINBASE_MATURITY

Observations:

1. In consensus.h, COINBASE_MATURITY is set to 100 for bitcoin
2. In FLO it is currently 100 as well

Solution:

• For FLO it should be 1500
• Optional: make it 1040 for simplicity in the next hard fork, maybe?