SDL_net is not very suitable for scrcpy.
For example, SDLNet_TCP_Accept() is non-blocking, so we have to wrap it
by calling many SDL_Net-specific functions to make it blocking.
But above all, SDLNet_TCP_Open() is a server socket only when no IP is
provided; otherwise, it's a client socket. Therefore, it is not possible
to create a server socket bound to localhost, so it accepts connections
from anywhere.
This is a problem for scrcpy, because on start, the application listens
for nearly 1 second until it accepts the first connection, supposedly
from the device. If someone on the local network manages to connect to
the server socket first, then they can stream arbitrary H.264 video.
This may be troublesome, for example during a public presentation ;-)
Provide our own simplified API (net.h) instead, implemented for the
different platforms.
The device serial was provided as a positional argument:
scrcpy 0123456789abcdef
Instead, expose it as an optional argument, -s or --serial:
scrcpy -s 0123456789abcdef
This avoids inconsistency between platforms when the positional
argument is passed before the options (which is undefined).
For readability, indent "case" in switch blocks.
Replace:
switch (x) {
case 1:
// ...
case 2:
// ...
case 3: { // a local scope block
int i = 42;
// ...
}
}
By:
switch (x) {
case 1:
// ...
case 2:
// ...
case 3: { // a local scope block
int i = 42;
// ...
}
}
Accept a parameter to limit the video size.
For instance, with "-m 960", the great side of the video will be scaled
down to 960 (if necessary), while the other side will be scaled down so
that the aspect ratio is preserved. Both dimensions must be a multiple
of 8, so black bands might be added, and the mouse positions must be
computed accordingly.
Romain Vimont