For every IPC message sent, we currently prepend the message size to the
IPC message buffer. This incurs the cost of copying the entire message
to its newly allocated position. Instead, reserve the bytes for the size
at the front of the buffer upon creation. Prevent dangerous access to
the buffer with specific public methods.
The type of MessageBuffer will be changing, and it was a bit awkward to
look around to find where the forward declaration was. This patch just
moves it to the obvious forwarding header.
In doing so, this removes all uses of the Encoder's stream operator,
except for where it is currently still used in the generated IPC code.
So the stream operator currently discards any errors, which is the
existing behavior. A subsequent commit will propagate the errors.
Currently, the generated IPC decoders will default-construct the type to
be decoded, then pass that value by reference to the concrete decoder.
This, of course, requires that the type is default-constructible. This
was an issue for decoding Variants, which had to require the first type
in the Variant list is Empty, to ensure it is default constructible.
Further, this made it possible for values to become uninitialized in
user-defined decoders.
This patch makes the decoder interface such that the concrete decoders
themselves contruct the decoded type upon return from the decoder. To do
so, the default decoders in IPC::Decoder had to be moved to the IPC
namespace scope, as these decoders are now specializations instead of
overloaded methods (C++ requires specializations to be in a namespace
scope).
For the most part, we try to provide specializations of these functions
in various headers by including "LibIPC/Forward.h" and then declaring
encode() and decode() specializations. However, without any forward
declaration of these types, we aren't actually specializing anything.
Rather, we are just declaring overloads, which trips up the base encode
and decode template definitions.
The result is that LibIPC is very sensitive to include order, and the
DependentFalse<> static assertion would fail if the includes weren't
perfectly ordered.
By properly forward declaring these templates, we can make sure the
specializations receive precedence over the base templates.
SPDX License Identifiers are a more compact / standardized
way of representing file license information.
See: https://spdx.dev/resources/use/#identifiers
This was done with the `ambr` search and replace tool.
ambr --no-parent-ignore --key-from-file --rep-from-file key.txt rep.txt *
