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//! Represents an object in PHP. Allows for overriding the internal object used
//! by classes, allowing users to store Rust data inside a PHP object.
use std::{
fmt::Debug,
mem,
ops::{Deref, DerefMut},
os::raw::c_char,
ptr::{self, NonNull},
};
use crate::{
boxed::{ZBox, ZBoxable},
class::RegisteredClass,
convert::{FromZendObject, FromZendObjectMut, FromZval, FromZvalMut, IntoZval},
error::{Error, Result},
ffi::{
ext_php_rs_zend_object_alloc, ext_php_rs_zend_object_release, object_properties_init,
zend_object, zend_object_std_init, zend_objects_clone_members,
},
flags::DataType,
types::{ZendObject, Zval},
zend::ClassEntry,
};
/// Representation of a Zend class object in memory.
#[repr(C)]
#[derive(Debug)]
pub struct ZendClassObject<T> {
pub obj: Option<T>,
pub std: ZendObject,
}
impl<T: RegisteredClass> ZendClassObject<T> {
/// Creates a new [`ZendClassObject`] of type `T`, where `T` is a
/// [`RegisteredClass`] in PHP, storing the given value `val` inside the
/// object.
///
/// # Parameters
///
/// * `val` - The value to store inside the object.
///
/// # Panics
///
/// Panics if memory was unable to be allocated for the new object.
pub fn new(val: T) -> ZBox<Self> {
// SAFETY: We are providing a value to initialize the object with.
unsafe { Self::internal_new(Some(val), None) }
}
/// Creates a new [`ZendClassObject`] of type `T`, with an uninitialized
/// internal object.
///
/// # Safety
///
/// As the object is uninitialized, the caller must ensure the following
/// until the internal object is initialized:
///
/// * The object is never dereferenced to `T`.
/// * The [`Clone`] implementation is never called.
/// * The [`Debug`] implementation is never called.
///
/// If any of these conditions are not met while not initialized, the
/// corresponding function will panic. Converting the object into its
/// inner pointer with the [`into_raw`] function is valid, however.
///
/// [`into_raw`]: #method.into_raw
///
/// # Panics
///
/// Panics if memory was unable to be allocated for the new object.
pub unsafe fn new_uninit(ce: Option<&'static ClassEntry>) -> ZBox<Self> {
Self::internal_new(None, ce)
}
/// Creates a new [`ZendObject`] of type `T`, storing the given (and
/// potentially uninitialized) `val` inside the object.
///
/// # Parameters
///
/// * `val` - Value to store inside the object. See safety section.
/// * `init` - Whether the given `val` was initialized.
///
/// # Safety
///
/// Providing an initialized variant of [`MaybeUninit<T>`] is safe.
///
/// Providing an uninitialized variant of [`MaybeUninit<T>`] is unsafe. As
/// the object is uninitialized, the caller must ensure the following
/// until the internal object is initialized:
///
/// * The object is never dereferenced to `T`.
/// * The [`Clone`] implementation is never called.
/// * The [`Debug`] implementation is never called.
///
/// If any of these conditions are not met while not initialized, the
/// corresponding function will panic. Converting the object into its
/// inner with the [`into_raw`] function is valid, however. You can
/// initialize the object with the [`initialize`] function.
///
/// [`into_raw`]: #method.into_raw
/// [`initialize`]: #method.initialize
///
/// # Panics
///
/// Panics if memory was unable to be allocated for the new object.
unsafe fn internal_new(val: Option<T>, ce: Option<&'static ClassEntry>) -> ZBox<Self> {
let size = mem::size_of::<ZendClassObject<T>>();
let meta = T::get_metadata();
let ce = ce.unwrap_or_else(|| meta.ce()) as *const _ as *mut _;
let obj = ext_php_rs_zend_object_alloc(size as _, ce) as *mut ZendClassObject<T>;
let obj = obj
.as_mut()
.expect("Failed to allocate for new Zend object");
zend_object_std_init(&mut obj.std, ce);
object_properties_init(&mut obj.std, ce);
// SAFETY: `obj` is non-null and well aligned as it is a reference.
// As the data in `obj.obj` is uninitialized, we don't want to drop
// the data, but directly override it.
ptr::write(&mut obj.obj, val);
obj.std.handlers = meta.handlers();
ZBox::from_raw(obj)
}
/// Initializes the class object with the value `val`.
///
/// # Parameters
///
/// * `val` - The value to initialize the object with.
///
/// # Returns
///
/// Returns the old value in an [`Option`] if the object had already been
/// initialized, [`None`] otherwise.
pub fn initialize(&mut self, val: T) -> Option<T> {
self.obj.replace(val)
}
/// Returns a mutable reference to the [`ZendClassObject`] of a given zend
/// object `obj`. Returns [`None`] if the given object is not of the
/// type `T`.
///
/// # Parameters
///
/// * `obj` - The zend object to get the [`ZendClassObject`] for.
pub fn from_zend_obj(std: &zend_object) -> Option<&Self> {
Some(Self::_from_zend_obj(std)?)
}
/// Returns a mutable reference to the [`ZendClassObject`] of a given zend
/// object `obj`. Returns [`None`] if the given object is not of the
/// type `T`.
///
/// # Parameters
///
/// * `obj` - The zend object to get the [`ZendClassObject`] for.
#[allow(clippy::needless_pass_by_ref_mut)]
pub fn from_zend_obj_mut(std: &mut zend_object) -> Option<&mut Self> {
Self::_from_zend_obj(std)
}
fn _from_zend_obj(std: &zend_object) -> Option<&mut Self> {
let std = std as *const zend_object as *const c_char;
let ptr = unsafe {
let ptr = std.offset(0 - Self::std_offset() as isize) as *const Self;
(ptr as *mut Self).as_mut()?
};
if ptr.std.instance_of(T::get_metadata().ce()) {
Some(ptr)
} else {
None
}
}
/// Returns a mutable reference to the underlying Zend object.
pub fn get_mut_zend_obj(&mut self) -> &mut zend_object {
&mut self.std
}
/// Returns the offset of the `std` property in the class object.
pub(crate) fn std_offset() -> usize {
unsafe {
let null = NonNull::<Self>::dangling();
let base = null.as_ref() as *const Self;
let std = &null.as_ref().std as *const zend_object;
(std as usize) - (base as usize)
}
}
}
impl<'a, T: RegisteredClass> FromZval<'a> for &'a ZendClassObject<T> {
const TYPE: DataType = DataType::Object(Some(T::CLASS_NAME));
fn from_zval(zval: &'a Zval) -> Option<Self> {
Self::from_zend_object(zval.object()?).ok()
}
}
impl<'a, T: RegisteredClass> FromZendObject<'a> for &'a ZendClassObject<T> {
fn from_zend_object(obj: &'a ZendObject) -> Result<Self> {
// TODO(david): replace with better error
ZendClassObject::from_zend_obj(obj).ok_or(Error::InvalidScope)
}
}
impl<'a, T: RegisteredClass> FromZvalMut<'a> for &'a mut ZendClassObject<T> {
const TYPE: DataType = DataType::Object(Some(T::CLASS_NAME));
fn from_zval_mut(zval: &'a mut Zval) -> Option<Self> {
Self::from_zend_object_mut(zval.object_mut()?).ok()
}
}
impl<'a, T: RegisteredClass> FromZendObjectMut<'a> for &'a mut ZendClassObject<T> {
fn from_zend_object_mut(obj: &'a mut ZendObject) -> Result<Self> {
ZendClassObject::from_zend_obj_mut(obj).ok_or(Error::InvalidScope)
}
}
unsafe impl<T: RegisteredClass> ZBoxable for ZendClassObject<T> {
fn free(&mut self) {
// SAFETY: All constructors guarantee that `self` contains a valid pointer.
// Further, all constructors guarantee that the `std` field of
// `ZendClassObject` will be initialized.
unsafe { ext_php_rs_zend_object_release(&mut self.std) }
}
}
impl<T> Deref for ZendClassObject<T> {
type Target = T;
fn deref(&self) -> &Self::Target {
self.obj
.as_ref()
.expect("Attempted to access uninitialized class object")
}
}
impl<T> DerefMut for ZendClassObject<T> {
fn deref_mut(&mut self) -> &mut Self::Target {
self.obj
.as_mut()
.expect("Attempted to access uninitialized class object")
}
}
impl<T: RegisteredClass + Default> Default for ZBox<ZendClassObject<T>> {
#[inline]
fn default() -> Self {
ZendClassObject::new(T::default())
}
}
impl<T: RegisteredClass + Clone> Clone for ZBox<ZendClassObject<T>> {
fn clone(&self) -> Self {
// SAFETY: All constructors of `NewClassObject` guarantee that it will contain a
// valid pointer. The constructor also guarantees that the internal
// `ZendClassObject` pointer will contain a valid, initialized `obj`,
// therefore we can dereference both safely.
unsafe {
let mut new = ZendClassObject::new((***self).clone());
zend_objects_clone_members(&mut new.std, &self.std as *const _ as *mut _);
new
}
}
}
impl<T: RegisteredClass> IntoZval for ZBox<ZendClassObject<T>> {
const TYPE: DataType = DataType::Object(Some(T::CLASS_NAME));
fn set_zval(self, zv: &mut Zval, _: bool) -> Result<()> {
let obj = self.into_raw();
zv.set_object(&mut obj.std);
Ok(())
}
}
impl<T: RegisteredClass> IntoZval for &mut ZendClassObject<T> {
const TYPE: DataType = DataType::Object(Some(T::CLASS_NAME));
#[inline]
fn set_zval(self, zv: &mut Zval, _: bool) -> Result<()> {
zv.set_object(&mut self.std);
Ok(())
}
}