This comment described how the constructor of CFeeRate was previously
indirectly used to parse fee rate arguments from RPCs. The command line
input was actually in sat/vB but due to the use of AmountFromValue() it
got converted to BTC/vB. In the constructor this could be rectified by
creating a CFeeRate from that given value (in BTC/vB) and COIN as the
transaction size, turning the input effectively to sat/vB. Since this
usage pattern was removed from the codebase some months ago, the comment
is now obsolete.
Also:
• Use vsize and vbyte instead of size and byte
When calculating the fee for a given tx size from a fee rate, we should
always round up to the next satoshi. Otherwise, if we round down (via
truncation), the calculated fee may result in a fee with a feerate
slightly less than targeted.
This is particularly important for coin selection as a slightly lower
feerate than expected can result in a variety of issues.
This resolves an issue where estimatesmartfee would return 999
sat/byte instead of 1000, due to floating point loss of precision
Thanks to sipa for suggesting is_integral.
CFeeRate and CTxMemPoolEntry have explicitly defined copy ctors which has the same functionality as the implicit default copy ctors which would have been generated otherwise.
Besides being redundant, it violates the rule of three (see https://en.wikipedia.org/wiki/Rule_of_three_(C%2B%2B_programming) ).
(Of course, the rule of three doesn't -really- cause a resource management issue here, but the reason for that is exactly that there is no need for an explicit copy ctor in the first place since no resources are being managed).
CFeeRate has an explicitly defined copy ctor which has the same functionality as the implicit default copy ctor which would h
ave been generated otherwise.
