When we merged the changes in libimagrt so that it automatically detects
whether stdin/stdout is a TTY and provides the user with stderr in case
stdout is not a TTY, we forgot that things like
imag foo | grep bar
becomes impossible with that, because imag detects that stdout is not a
tty and automatically uses stderr for output.
But in this case, we don't want that. The output has to be stdout in
this case.
With this change, we have a flag in the runtime ("--pipe-magic" or "-P",
globally available) which turns on "pipe magic".
The expected behaviour is the following, if "-P" is passed:
* If stdout is a TTY, we print to stdout
* If stdout is not a TTY, we print to stderr
* If stdin is not a TTY, we do not provide it
If "-P" is not passed, we allow the user of libimagrt to use stdin for
interactive stuff (the interactive stuff is not yet implemented).
Signed-off-by: Matthias Beyer <mail@beyermatthias.de>
Unfortunately, our latest fix to file parsing did not solve all issues.
So we have to fix it _again_.
The problem was the `std::str::Lines` iterator, which apparently fails
this:
assert_eq!(1, "".lines().count());
as an empty line seems not to be a line.
Because of that, when reading a file with an empty line at its bottom
got stripped off that line.
This patch removes the use of the `lines()` iterator and uses
`split("\n")` instead. This only works on Unix operating systems, but as
we only target unix operating systems with imag, this is not considered
an issue right now.
This patch also adds extensive tests on multiple levels in the
`libimagstore` implementation:
* On the parsing level, for the function which implements the parsing
* On the filesystem abstraction levels
* On the `Store` levels
to make sure that everything is parsed correctly.
This is another approach for providing access to stdin/out/err via
libimagrt::runtime::Runtime.
The Runtime object does configure which output gets returned (stdout if
stdout is a tty, else stderr).
With this we can change libimagrt to read/write the store from/to
stdin/stdout without the user noticing that she does not write to stdout
but stderr.
Reading from stdin is not possible then, though.
This way we can control whether "out" output goes to stdout or stderr
without the user of the functionality knowing.
This is useful for later when we use libimagrt to automatically
read and write the store from and to stdout/in depending on whether we
are talking to a TTY or a pipe.
