`Stream` will be qualified as `AK::Stream` until we remove the
`Core::Stream` namespace. `IODevice` now reuses the `SeekMode` that is
defined by `SeekableStream`, since defining its own would require us to
qualify it with `AK::SeekMode` everywhere.
At the moment, there is no immediate advantage compared to just calling
the underlying functions directly, but having a common interface feels
more ergonomic (users don't have to care about how a type serializes)
and maybe we'll find a way to hide the actual implementation from direct
access some time in the future.
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.
While at it, rename the `read_trivial_value` and `write_trivial_value`
functions to `read_value` and `write_value` respectively, since we'll
add compatibility for non-trivial types down the line.
We don't need to call `can_read_line()` as the buffer will be populated
by `find_and_populate_until_any_of()`. The change is also beneficial as
the buffer will be populated until a candidate is found and not
necessarily a new line.
The search used to go through the buffer from the start, even if we just
appended a small number of bytes at the end. It now remembers the last
stop and resume the search from it.
This parameter allows to start searching after an offset. For example,
to resume a search.
It is unfortunately a breaking change in API so this patch also modifies
one user and one test.
These instances were detected by searching for files that include
MemMem.h, but don't match the regex:
\\b(MemMem(?!\.h>)|bitap_bitwise|memmem|memmem_optional)\\b
These are the only symbols defined by MemMem.h.
In theory, one might use LibCPP to detect things like this
automatically, but let's do this one step after another.
This essentially wraps a `NonnullOwnPtr` or a reference, allowing us to
either have a stream own a dependent stream that it uses or to just hold
a reference if a stream is already owned by somebody else and we just
want to use it temporarily.
This generally seems like a better name, especially if we somehow also
need a better name for "read the entire buffer, but not the entire file"
somewhere down the line.
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.
`Core::Stream::File` shouldn't hold any utility methods that are
unrelated to constructing a `Core::Stream`, so let's just replace the
existing `Core::File::exists` with the nicer looking implementation.
We have a new, improved string type coming up in AK (OOM aware, no null
state), and while it's going to use UTF-8, the name UTF8String is a
mouthful - so let's free up the String name by renaming the existing
class.
Making the old one have an annoying name will hopefully also help with
quick adoption :^)
When creating a `Core::Stream::Socket`, you can now choose to prevent
SIGPIPE signals from firing and terminating your process. This is done
by passing MSG_NOSIGNAL to the `System::recv()` or `System::send()`
calls when you `read()` or `write()` to that Socket.
Previously, this would cause an assert to fail if one reads a completely
buffered line into a buffer that is smaller than the Stream's internal
buffer.
For the general case, allocations will always have the size of a block.
In case of a smaller read a block will be filled entirely before another
allocation appends.
It also adds a specialization for Stream::File::read_all() that tries to
detect the size of the file with fstat to perform a single allocation.
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
