This is the easiest and cleanest way to get logging into some of the
fundamental APIs, such as the database and TLS APIs. We don't want to
have to pass logging functions to those, but they can safely use the
global logging configuration.
Not only does this make us more POSIX, it actually makes things a lot
easier because TLS implementations will need to be able to access the
trusted certificates file, which most likely will not live in the
data directory.
Both do buffered reads and writes, but IoCopy() uses IoRead() and
IoWrite() directly, whereas StreamCopy() relies on StreamGetc() and
StreamPutc(), which manipulate the stream buffers.
If we haven't read any bytes yet, then we try a few times a few ms apart
to see if we get anything. If not, treat it as an EOF. Otherwise, read
bytes until we get an EOF or EAGAIN. EAGAIN after a consistent read of
bytes is treaded as an EOF immediately.
These functions previously operated on the assumption that fgetc() would
block; however it will not block on HttpServer streams because those are
non-blocking. They now check error conditions properly before failing
prematurely.
You might be asking why I would just write a simple curl replacement
when curl does the job just fine. Well, the most immediate reason is
to test the HttpClient API, but since Telodendria's goal is to not
be dependent on any third-party code if at all possible, it makes
sense to have a simple HTTP client to use not only for testing
Telodendria, but also for configuring it. When we move the
configuration to the database, we'll ship a script that uses this
tool to allow admins to easily submit API requests.
Do not be concerned that HttpClient does not support TLS yet. TLS
support is necessary for federation to work, so it is coming
eventually.
