This is an extraction of ArgsManager related functions from util/system
into their own common file.
Config file related functions are moved to common/config.cpp.
The background of this commit is an ongoing effort to decouple the
libbitcoinkernel library from the ArgsManager. The ArgsManager belongs
into the common library, since the kernel library should not depend on
it. See doc/design/libraries.md for more information on this rationale.
The fs.* files are already part of the libbitcoin_util library. With the
introduction of the fs_helpers.* it makes sense to move fs.* into the
util/ directory as well.
Add common InitConfig function to deduplicate bitcoind and bitcoin-qt code
reading config files and creating the datadir.
There are a few minor changes in behavior:
- In bitcoin-qt, when there is a problem reading the configuration file, the
GUI error text has changed from "Error: Cannot parse configuration file:" to
"Error reading configuration file:" to be consistent with bitcoind.
- In bitcoind, when there is a problem reading the settings.json file, the
error text has changed from "Failed loading settings file" to "Settings
file could not be read" to be consistent with bitcoin-qt.
- In bitcoind, when there is a problem writing the settings.json file, the
error text has changed from "Failed saving settings file" to "Settings file
could not be written" to be consistent with bitcoin-qt.
- In bitcoin-qt, if there datadir is not accessible (e.g. no permission to read),
there is an normal error dialog showing "Error: filesystem error: status:
Permission denied [.../settings.json]", instead of an uncaught exception
