As agreed in the "vtables and procedural macros" thread on the mailing list.
Signed-off-by: Paolo Bonzini <pbonz...@redhat.com> --- docs/devel/rust.rst | 44 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 44 insertions(+) diff --git a/docs/devel/rust.rst b/docs/devel/rust.rst index 390aae43866..8cccca7a734 100644 --- a/docs/devel/rust.rst +++ b/docs/devel/rust.rst @@ -194,6 +194,50 @@ module status interface either. Also, ``unsafe`` interfaces may be replaced by safe interfaces later. +Naming convention +''''''''''''''''' + +C function names usually are prefixed according to the data type that they +apply to, for example ``timer_mod`` or ``sysbus_connect_irq``. Furthermore, +both function and structs sometimes have a ``qemu_`` or ``QEMU`` prefix. +Generally speaking, these are all removed in the corresponding Rust functions: +``QEMUTimer`` becomes ``timer::Timer``, ``timer_mod`` becomes ``Timer::modify``, +``sysbus_connect_irq`` becomes ``SysBusDeviceMethods::connect_irq``. + +Sometimes however a name appears multiple times in the QOM class hierarchy, +and the only difference is in the prefix. An example is ``qdev_realize`` and +``sysbus_realize``. In such cases, whenever a name is not unique in +the hierarchy, always add the prefix to the classes that are lower in +the hierarchy; for the top class, decide on a case by case basis. + +For example: + +========================== ========================================= +``device_cold_reset()`` ``DeviceMethods::cold_reset()`` +``pci_device_reset()`` ``PciDeviceMethods::pci_device_reset()`` +``pci_bridge_reset()`` ``PciBridgeMethods::pci_bridge_reset()`` +========================== ========================================= + +Here, the name is not exactly the same, but nevertheless ``PciDeviceMethods`` +adds the prefix to avoid confusion, because the functionality of +``device_cold_reset()`` and ``pci_device_reset()`` is subtly different. + +In this case, however, no prefix is needed: + +========================== ========================================= +``device_realize()`` ``DeviceMethods::realize()`` +``sysbus_realize()`` ``SysbusDeviceMethods::sysbus_realize()`` +``pci_realize()`` ``PciDeviceMethods::pci_realize()`` +========================== ========================================= + +Here, the lower classes do not add any functionality, and mostly +provide extra compile-time checking; the basic *realize* functionality +is the same for all devices. Therefore, ``DeviceMethods`` does not +add the prefix. + +Whenever a name is unique in the hierarchy, instead, you should +always remove the class name prefix. + Common pitfalls ''''''''''''''' -- 2.48.1
