Add infrastructure for casting from/to memory subtypes

This commit is contained in:
Christian Meissl 2022-02-26 16:15:21 +01:00 committed by Sebastian Dröge
parent 240da14042
commit 44d39f8824
2 changed files with 358 additions and 5 deletions

View file

@ -335,6 +335,8 @@ pub mod prelude {
SpecificFormattedValueIntrinsic,
};
pub use crate::utils::Displayable;
pub use crate::memory::MemoryType;
}
#[macro_use]

View file

@ -3,7 +3,7 @@
use std::fmt;
use std::marker::PhantomData;
use std::mem;
use std::ops;
use std::ops::{Deref, DerefMut};
use std::ptr;
use std::slice;
@ -359,7 +359,7 @@ impl<'a> AsMut<[u8]> for MemoryMap<'a, Writable> {
}
}
impl<'a, T> ops::Deref for MemoryMap<'a, T> {
impl<'a, T> Deref for MemoryMap<'a, T> {
type Target = [u8];
fn deref(&self) -> &[u8] {
@ -367,7 +367,7 @@ impl<'a, T> ops::Deref for MemoryMap<'a, T> {
}
}
impl<'a> ops::DerefMut for MemoryMap<'a, Writable> {
impl<'a> DerefMut for MemoryMap<'a, Writable> {
fn deref_mut(&mut self) -> &mut [u8] {
self.as_mut_slice()
}
@ -447,7 +447,7 @@ impl AsMut<[u8]> for MappedMemory<Writable> {
}
}
impl<T> ops::Deref for MappedMemory<T> {
impl<T> Deref for MappedMemory<T> {
type Target = [u8];
fn deref(&self) -> &[u8] {
@ -455,7 +455,7 @@ impl<T> ops::Deref for MappedMemory<T> {
}
}
impl ops::DerefMut for MappedMemory<Writable> {
impl DerefMut for MappedMemory<Writable> {
fn deref_mut(&mut self) -> &mut [u8] {
self.as_mut_slice()
}
@ -522,6 +522,342 @@ impl<'a> fmt::Debug for Dump<'a> {
}
}
pub unsafe trait MemoryType: crate::prelude::IsMiniObject + AsRef<Memory>
where
<Self as crate::prelude::IsMiniObject>::RefType: AsRef<MemoryRef> + AsMut<MemoryRef>,
{
fn check_memory_type(mem: &MemoryRef) -> bool;
}
#[derive(Debug, thiserror::Error)]
pub enum MemoryTypeMismatchError {
#[error(transparent)]
ValueTypeMismatch(#[from] glib::value::ValueTypeMismatchError),
#[error("the memory is not of the requested type {requested}")]
MemoryTypeMismatch { requested: &'static str },
}
pub struct MemoryTypeValueTypeChecker<M>(PhantomData<M>);
unsafe impl<M> glib::value::ValueTypeChecker for MemoryTypeValueTypeChecker<M>
where
M: MemoryType + glib::StaticType,
<M as crate::prelude::IsMiniObject>::RefType: AsRef<MemoryRef> + AsMut<MemoryRef>,
{
type Error = glib::value::ValueTypeMismatchOrNoneError<MemoryTypeMismatchError>;
fn check(value: &glib::Value) -> Result<(), Self::Error> {
skip_assert_initialized!();
let mem = value.get::<&Memory>().map_err(|err| match err {
glib::value::ValueTypeMismatchOrNoneError::UnexpectedNone => {
glib::value::ValueTypeMismatchOrNoneError::UnexpectedNone
}
glib::value::ValueTypeMismatchOrNoneError::WrongValueType(err) => {
glib::value::ValueTypeMismatchOrNoneError::WrongValueType(
MemoryTypeMismatchError::ValueTypeMismatch(err),
)
}
})?;
if mem.is_memory_type::<M>() {
Ok(())
} else {
Err(glib::value::ValueTypeMismatchOrNoneError::WrongValueType(
MemoryTypeMismatchError::MemoryTypeMismatch {
requested: std::any::type_name::<M>(),
},
))
}
}
}
impl AsRef<MemoryRef> for MemoryRef {
fn as_ref(&self) -> &MemoryRef {
self
}
}
impl AsMut<MemoryRef> for MemoryRef {
fn as_mut(&mut self) -> &mut MemoryRef {
self
}
}
impl AsRef<Memory> for Memory {
fn as_ref(&self) -> &Memory {
self
}
}
unsafe impl MemoryType for Memory {
fn check_memory_type(_mem: &MemoryRef) -> bool {
skip_assert_initialized!();
true
}
}
impl Memory {
pub fn downcast_memory<M: MemoryType>(self) -> Result<M, Self>
where
<M as crate::prelude::IsMiniObject>::RefType: AsRef<MemoryRef> + AsMut<MemoryRef>,
{
if M::check_memory_type(&self) {
unsafe { Ok(from_glib_full(self.into_ptr() as *mut M::FfiType)) }
} else {
Err(self)
}
}
}
impl MemoryRef {
pub fn is_memory_type<M: MemoryType>(&self) -> bool
where
<M as crate::prelude::IsMiniObject>::RefType: AsRef<MemoryRef> + AsMut<MemoryRef>,
{
M::check_memory_type(self)
}
pub fn downcast_memory_ref<M: MemoryType>(&self) -> Option<&M::RefType>
where
<M as crate::prelude::IsMiniObject>::RefType: AsRef<MemoryRef> + AsMut<MemoryRef>,
{
if M::check_memory_type(self) {
unsafe { Some(&*(self as *const Self as *const M::RefType)) }
} else {
None
}
}
pub fn downcast_memory_mut<M: MemoryType>(&mut self) -> Option<&mut M::RefType>
where
<M as crate::prelude::IsMiniObject>::RefType: AsRef<MemoryRef> + AsMut<MemoryRef>,
{
if M::check_memory_type(self) {
unsafe { Some(&mut *(self as *mut Self as *mut M::RefType)) }
} else {
None
}
}
}
#[macro_export]
macro_rules! memory_object_wrapper {
($name:ident, $ref_name:ident, $ffi_name:path, $mem_type_check:expr, $parent_memory_type:path, $parent_memory_ref_type:path) => {
$crate::mini_object_wrapper!($name, $ref_name, $ffi_name);
unsafe impl $crate::memory::MemoryType for $name {
fn check_memory_type(mem: &$crate::MemoryRef) -> bool {
skip_assert_initialized!();
$mem_type_check(mem)
}
}
impl $name {
pub fn downcast_memory<M: $crate::memory::MemoryType>(self) -> Result<M, Self>
where
<M as $crate::miniobject::IsMiniObject>::RefType: AsRef<$crate::MemoryRef>
+ AsMut<$crate::MemoryRef>
+ AsRef<$ref_name>
+ AsMut<$ref_name>,
{
if M::check_memory_type(&self) {
unsafe {
Ok($crate::glib::translate::from_glib_full(
self.into_ptr() as *mut M::FfiType
))
}
} else {
Err(self)
}
}
pub fn upcast_memory<M>(self) -> M
where
M: $crate::memory::MemoryType
+ $crate::glib::translate::FromGlibPtrFull<
*const <M as $crate::miniobject::IsMiniObject>::FfiType,
>,
<M as $crate::miniobject::IsMiniObject>::RefType:
AsRef<$crate::MemoryRef> + AsMut<$crate::MemoryRef>,
Self: AsRef<M>,
{
unsafe {
$crate::glib::translate::from_glib_full(
self.into_ptr() as *const <M as $crate::miniobject::IsMiniObject>::FfiType
)
}
}
}
impl $ref_name {
pub fn upcast_memory_ref<M>(&self) -> &M::RefType
where
M: $crate::memory::MemoryType,
<M as $crate::miniobject::IsMiniObject>::RefType:
AsRef<$crate::MemoryRef> + AsMut<$crate::MemoryRef>,
Self: AsRef<M::RefType> + AsMut<M::RefType>
{
self.as_ref()
}
pub fn upcast_memory_mut<M>(&mut self) -> &mut M::RefType
where
M: $crate::memory::MemoryType,
<M as $crate::miniobject::IsMiniObject>::RefType:
AsRef<$crate::MemoryRef> + AsMut<$crate::MemoryRef>,
Self: AsRef<M::RefType> + AsMut<M::RefType>
{
self.as_mut()
}
}
impl std::ops::Deref for $ref_name {
type Target = $parent_memory_ref_type;
fn deref(&self) -> &Self::Target {
unsafe { &*(self as *const _ as *const Self::Target) }
}
}
impl std::ops::DerefMut for $ref_name {
fn deref_mut(&mut self) -> &mut Self::Target {
unsafe { &mut *(self as *mut _ as *mut Self::Target) }
}
}
impl AsRef<$parent_memory_type> for $name {
fn as_ref(&self) -> &$parent_memory_type {
unsafe { &*(self as *const _ as *const $parent_memory_type) }
}
}
impl AsRef<$parent_memory_ref_type> for $ref_name {
fn as_ref(&self) -> &$parent_memory_ref_type {
self
}
}
impl AsMut<$parent_memory_ref_type> for $ref_name {
fn as_mut(&mut self) -> &mut $parent_memory_ref_type {
&mut *self
}
}
impl $crate::glib::types::StaticType for $name {
fn static_type() -> glib::types::Type {
$ref_name::static_type()
}
}
impl $crate::glib::types::StaticType for $ref_name {
fn static_type() -> $crate::glib::types::Type {
unsafe { $crate::glib::translate::from_glib($crate::ffi::gst_memory_get_type()) }
}
}
impl $crate::glib::value::ValueType for $name {
type Type = Self;
}
unsafe impl<'a> $crate::glib::value::FromValue<'a> for $name {
type Checker = $crate::memory::MemoryTypeValueTypeChecker<Self>;
unsafe fn from_value(value: &'a $crate::glib::Value) -> Self {
skip_assert_initialized!();
$crate::glib::translate::from_glib_none($crate::glib::gobject_ffi::g_value_get_boxed(
$crate::glib::translate::ToGlibPtr::to_glib_none(value).0,
) as *mut $ffi_name)
}
}
unsafe impl<'a> $crate::glib::value::FromValue<'a> for &'a $name {
type Checker = $crate::memory::MemoryTypeValueTypeChecker<$name>;
unsafe fn from_value(value: &'a $crate::glib::Value) -> Self {
skip_assert_initialized!();
assert_eq!(
std::mem::size_of::<$name>(),
std::mem::size_of::<$crate::glib::ffi::gpointer>()
);
let value = &*(value as *const $crate::glib::Value as *const $crate::glib::gobject_ffi::GValue);
let ptr = &value.data[0].v_pointer as *const $crate::glib::ffi::gpointer
as *const *const $ffi_name;
assert!(!(*ptr).is_null());
&*(ptr as *const $name)
}
}
impl $crate::glib::value::ToValue for $name {
fn to_value(&self) -> $crate::glib::Value {
let mut value = $crate::glib::Value::for_value_type::<Self>();
unsafe {
$crate::glib::gobject_ffi::g_value_set_boxed(
$crate::glib::translate::ToGlibPtrMut::to_glib_none_mut(&mut value).0,
$crate::glib::translate::ToGlibPtr::<*const $ffi_name>::to_glib_none(self).0
as *mut _,
)
}
value
}
fn value_type(&self) -> glib::Type {
<Self as glib::StaticType>::static_type()
}
}
impl $crate::glib::value::ToValueOptional for $name {
fn to_value_optional(s: Option<&Self>) -> $crate::glib::Value {
skip_assert_initialized!();
let mut value = $crate::glib::Value::for_value_type::<Self>();
unsafe {
$crate::glib::gobject_ffi::g_value_set_boxed(
$crate::glib::translate::ToGlibPtrMut::to_glib_none_mut(&mut value).0,
$crate::glib::translate::ToGlibPtr::<*const $ffi_name>::to_glib_none(&s).0
as *mut _,
)
}
value
}
}
unsafe impl<'a> $crate::glib::value::FromValue<'a> for &'a $ref_name {
type Checker = $crate::memory::MemoryTypeValueTypeChecker<$name>;
unsafe fn from_value(value: &'a glib::Value) -> Self {
skip_assert_initialized!();
&*($crate::glib::gobject_ffi::g_value_get_boxed($crate::glib::translate::ToGlibPtr::to_glib_none(value).0)
as *const $ref_name)
}
}
// Can't have SetValue/SetValueOptional impls as otherwise one could use it to get
// immutable references from a mutable reference without borrowing via the value
};
($name:ident, $ref_name:ident, $ffi_name:path, $mem_type_check:expr, $parent_memory_type:path, $parent_memory_ref_type:path, $($parent_parent_memory_type:path, $parent_parent_memory_ref_type:path),*) => {
$crate::memory_object_wrapper!($name, $ref_name, $ffi_name, $mem_type_check, $parent_memory_type, $parent_memory_ref_type);
$(
impl AsRef<$parent_parent_memory_type> for $name {
fn as_ref(&self) -> &$parent_parent_memory_type {
unsafe { &*(self as *const _ as *const $parent_parent_memory_type) }
}
}
impl AsRef<$parent_parent_memory_ref_type> for $ref_name {
fn as_ref(&self) -> &$parent_parent_memory_ref_type {
self
}
}
impl AsMut<$parent_parent_memory_ref_type> for $ref_name {
fn as_mut(&mut self) -> &mut $parent_parent_memory_ref_type {
&mut *self
}
}
)*
};
}
#[cfg(test)]
mod tests {
#[test]
@ -537,4 +873,19 @@ mod tests {
let mem = crate::Memory::from_slice(vec![0; 64]);
dbg!(mem.dump(None));
}
#[test]
fn test_value() {
use glib::prelude::*;
crate::init().unwrap();
let v = None::<&crate::Memory>.to_value();
assert!(matches!(v.get::<Option<crate::Memory>>(), Ok(None)));
let mem = crate::Memory::from_slice(vec![1, 2, 3, 4]);
let v = mem.to_value();
assert!(matches!(v.get::<Option<crate::Memory>>(), Ok(Some(_))));
assert!(matches!(v.get::<crate::Memory>(), Ok(_)));
}
}