A negative return value doesn't make sense for any of those functions.
The return types were inherited from POSIX, where they also need to have
an indicator for an error (negative values).
This saves us an actual seek and rereading already stored buffer data in
cases where the seek is entirely covered by the currently buffered data.
This is especially important since we implement `discard` using `seek`
for seekable streams.
Also add some tests that ensure that the input and output streams match
each other, because I can't wrap my head around what the internal
representation looks like.
This is a first step towards handling OOM errors instead of just
crashing the program.
Now UDPServer's method `receive()` return memory allocation
errors explicitly with help of ErrorOr.
This removes one FIXME and make a bunch of new ones. :(
Next to functions like `is_eof` these were really confusing to use, and
the `read`/`write` functions should fail anyways if a stream is not
readable/writable.
Each of these strings would previously rely on StringView's char const*
constructor overload, which would call __builtin_strlen on the string.
Since we now have operator ""sv, we can replace these with much simpler
versions. This opens the door to being able to remove
StringView(char const*).
No functional changes.
Similar reasoning to making Core::Stream::read() return Bytes, except
that every user of read_line() creates a StringView from the result, so
let's just return one right away.
A mistake I've repeatedly made is along these lines:
```c++
auto nread = TRY(source_file->read(buffer));
TRY(destination_file->write(buffer));
```
It's a little clunky to have to create a Bytes or StringView from the
buffer's data pointer and the nread, and easy to forget and just use
the buffer. So, this patch changes the read() function to return a
Bytes of the data that were just read.
The other read_foo() methods will be modified in the same way in
subsequent commits.
Fixes#13687
Apologies for the enormous commit, but I don't see a way to split this
up nicely. In the vast majority of cases it's a simple change. A few
extra places can use TRY instead of manual error checking though. :^)
The event loop system was previously very singletony to the point that
there's only a single event loop stack per process and only one event
loop (the topmost) can run at a time. This commit simply makes the event
loop stack and related structures thread-local so that each thread has
an isolated event loop system.
Some things are kept at a global level and synchronized with the new
MutexProtected: The main event loop needs to still be obtainable from
anywhere, as it closes down the application when it exits. The ID
allocator is global as IDs should not be shared even between threads.
And for the inspector server connection, the same as for the main loop
holds.
Note that currently, the wake pipe is only created by the main thread,
so notifications don't work on other threads.
This removes the temporary mutex fix for notifiers, introduced in
0631d3fed5 .
This test makes sure that Socket classes such as TCPSocket properly
return an error when connection fails rather than crashing or creating
an invalid object.
Accidentally regressed this test during the Core::LocalServer refactor,
and didn't catch it since TestLibCoreStream is disabled in the CI right
now. We have to wait for some data to become available, as pending_bytes
will immediately return 0 and a 0-sized read immediately returns.
This change unfortunately cannot be atomically made without a single
commit changing everything.
Most of the important changes are in LibIPC/Connection.cpp,
LibIPC/ServerConnection.cpp and LibCore/LocalServer.cpp.
The notable changes are:
- IPCCompiler now generates the decode and decode_message functions such
that they take a Core::Stream::LocalSocket instead of the socket fd.
- IPC::Decoder now uses the receive_fd method of LocalSocket instead of
doing system calls directly on the fd.
- IPC::ConnectionBase and related classes now use the Stream API
functions.
- IPC::ServerConnection no longer constructs the socket itself; instead,
a convenience macro, IPC_CLIENT_CONNECTION, is used in place of
C_OBJECT and will generate a static try_create factory function for
the ServerConnection subclass. The subclass is now responsible for
passing the socket constructed in this function to its
ServerConnection base; the socket is passed as the first argument to
the constructor (as a NonnullOwnPtr<Core::Stream::LocalServer>) before
any other arguments.
- The functionality regarding taking over sockets from SystemServer has
been moved to LibIPC/SystemServerTakeover.cpp. The Core::LocalSocket
implementation of this functionality hasn't been deleted due to my
intention of removing this class in the near future and to reduce
noise on this (already quite noisy) PR.
As per previous discussion, it was decided that the Stream classes
should be constructed on the heap.
While I don't personally agree with this change, it does have the
benefit of avoiding Function object reconstructions due to the lambda
passed to Notifier pointing to a stale object reference. This also has
the benefit of not having to "box" objects for virtual usage, as the
objects come pre-boxed.
However, it means that we now hit the heap everytime we construct a
TCPSocket for instance, which might not be desirable.
It was possible for the "local_socket_read" and "local_socket_write"
tests to fail because we had exited the EventLoop before
BackgroundAction got around to invoking the completion callback.
The crash happened when trying to deferred_invoke() on the background
thread, calling Core::EventLoop::current() after said EventLoop had
returned from exec().
Fix this by not passing a completion callback, since we didn't need
one in the first place.
