This lock/unlock pair allows for the cller to lock a configuration file
to avoid concurrent operations.
It also allows for a transactional approach to updating a configuration
file. If multiple updates must be made atomically, they can be done
while the config is locked.
When a configuration file is locked, any updates made to it will be done
to the in-memory copy of the file. This allows for multiple updates to
happen while we hold the lock, preventing races during complex
config-file manipulation.
Add a test that exposes a bug in config_write.
It is valid to have multiple separate headers for the same config section, but
config_write will exit after finding the first matching section in certain
situations.
This test proves that config_write will duplicate a variable that already
exists instead of overwriting it if the variable is defined under a duplicate
section header.
Previously we would try to be clever when writing the configuration
file and try to stop parsing (and simply copy the rest of the old
file) when we either found the value we were trying to write,
or when we left the section that value was in, the assumption being
that there was no more work to do.
Regrettably, you can have another section with the same name later
in the file, and we must cope with that gracefully, thus we read the
whole file in order to write a new file.
Now, writing a file looks even more than reading. Pull the config
parsing out into its own function that can be used by both reading
and writing the configuration.
Add a unittest to validate bug #3043, where a duplicate empty config header
could cause deletion of a config entry to fail silently. The bug is currently
unresolved and this test will fail.
This changes the get_entry() method to return a refcounted version of
the config entry, which you have to free when you're done.
This allows us to avoid freeing the memory in which the entry is stored
on a refresh, which may happen at any time for a live config.
For this reason, get_string() has been forbidden on live configs and a
new function get_string_buf() has been added, which stores the string in
a git_buf which the user then owns.
The functions which parse the string value takea advantage of the
borrowing to parse safely and then release the entry.
On set, we set/add the value written to the config's internal values,
but we do not refresh old values.
Document this in a test in preparation for the refresh changes.
This adds giterr_user_cancel to return GIT_EUSER and clear any
error message that is sitting around. As a result of using that
in places, we need to be more thorough with capturing errors that
happen inside a callback when used internally. To help with that,
this also adds giterr_capture and giterr_restore so that when we
internally use a foreach-type function that clears errors and
converts them to GIT_EUSER, it is easier to restore not just the
return value, but the actual error message text.
