comm-central/third_party/rust/core-foundation/src/base.rs

Revision control

Copy as Markdown

Other Tools

// Copyright 2013 The Servo Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
use std;
use std::fmt;
use std::marker::PhantomData;
use std::mem;
use std::mem::ManuallyDrop;
use std::ops::{Deref, DerefMut};
use std::os::raw::c_void;
pub use core_foundation_sys::base::*;
use crate::string::CFString;
use crate::ConcreteCFType;
pub trait CFIndexConvertible {
/// Always use this method to construct a `CFIndex` value. It performs bounds checking to
/// ensure the value is in range.
fn to_CFIndex(self) -> CFIndex;
}
impl CFIndexConvertible for usize {
#[inline]
fn to_CFIndex(self) -> CFIndex {
let max_CFIndex = CFIndex::max_value();
if self > (max_CFIndex as usize) {
panic!("value out of range")
}
self as CFIndex
}
}
declare_TCFType! {
/// Superclass of all Core Foundation objects.
CFType, CFTypeRef
}
impl CFType {
/// Try to downcast the `CFType` to a subclass. Checking if the instance is the
/// correct subclass happens at runtime and `None` is returned if it is not the correct type.
/// Works similar to [`Box::downcast`] and [`CFPropertyList::downcast`].
///
/// # Examples
///
/// ```
/// # use core_foundation::string::CFString;
/// # use core_foundation::boolean::CFBoolean;
/// # use core_foundation::base::{CFType, TCFType};
/// #
/// // Create a string.
/// let string: CFString = CFString::from_static_string("FooBar");
/// // Cast it up to a CFType.
/// let cf_type: CFType = string.as_CFType();
/// // Cast it down again.
/// assert_eq!(cf_type.downcast::<CFString>().unwrap().to_string(), "FooBar");
/// // Casting it to some other type will yield `None`
/// assert!(cf_type.downcast::<CFBoolean>().is_none());
/// ```
///
/// ```compile_fail
/// # use core_foundation::array::CFArray;
/// # use core_foundation::base::TCFType;
/// # use core_foundation::boolean::CFBoolean;
/// # use core_foundation::string::CFString;
/// #
/// let boolean_array = CFArray::from_CFTypes(&[CFBoolean::true_value()]).into_CFType();
///
/// // This downcast is not allowed and causes compiler error, since it would cause undefined
/// // behavior to access the elements of the array as a CFString:
/// let invalid_string_array = boolean_array
/// .downcast_into::<CFArray<CFString>>()
/// .unwrap();
/// ```
///
/// [`CFPropertyList::downcast`]: ../propertylist/struct.CFPropertyList.html#method.downcast
#[inline]
pub fn downcast<T: ConcreteCFType>(&self) -> Option<T> {
if self.instance_of::<T>() {
unsafe {
let reference = T::Ref::from_void_ptr(self.0);
Some(T::wrap_under_get_rule(reference))
}
} else {
None
}
}
/// Similar to [`downcast`], but consumes self and can thus avoid touching the retain count.
///
/// [`downcast`]: #method.downcast
#[inline]
pub fn downcast_into<T: ConcreteCFType>(self) -> Option<T> {
if self.instance_of::<T>() {
unsafe {
let reference = T::Ref::from_void_ptr(self.0);
mem::forget(self);
Some(T::wrap_under_create_rule(reference))
}
} else {
None
}
}
}
impl fmt::Debug for CFType {
/// Formats the value using [`CFCopyDescription`].
///
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
let desc = unsafe { CFString::wrap_under_create_rule(CFCopyDescription(self.0)) };
desc.fmt(f)
}
}
impl Clone for CFType {
#[inline]
fn clone(&self) -> CFType {
unsafe { TCFType::wrap_under_get_rule(self.0) }
}
}
impl PartialEq for CFType {
#[inline]
fn eq(&self, other: &CFType) -> bool {
unsafe { CFEqual(self.as_CFTypeRef(), other.as_CFTypeRef()) != 0 }
}
}
declare_TCFType!(CFAllocator, CFAllocatorRef);
impl_TCFType!(CFAllocator, CFAllocatorRef, CFAllocatorGetTypeID);
impl CFAllocator {
#[inline]
pub fn new(mut context: CFAllocatorContext) -> CFAllocator {
unsafe {
let allocator_ref = CFAllocatorCreate(kCFAllocatorDefault, &mut context);
TCFType::wrap_under_create_rule(allocator_ref)
}
}
}
/// All Core Foundation types implement this trait. The associated type `Ref` specifies the
/// associated Core Foundation type: e.g. for `CFType` this is `CFTypeRef`; for `CFArray` this is
/// `CFArrayRef`.
///
/// Most structs that implement this trait will do so via the [`impl_TCFType`] macro.
///
/// [`impl_TCFType`]: ../macro.impl_TCFType.html
pub trait TCFType {
/// The reference type wrapped inside this type.
type Ref: TCFTypeRef;
/// Returns the object as its concrete `TypeRef`.
fn as_concrete_TypeRef(&self) -> Self::Ref;
/// Returns an instance of the object, wrapping the underlying `CFTypeRef` subclass. Use this
/// when following Core Foundation's "Create Rule". The reference count is *not* bumped.
unsafe fn wrap_under_create_rule(obj: Self::Ref) -> Self;
/// Returns the type ID for this class.
fn type_id() -> CFTypeID;
/// Returns the object as a wrapped `CFType`. The reference count is incremented by one.
#[inline]
fn as_CFType(&self) -> CFType {
unsafe { TCFType::wrap_under_get_rule(self.as_CFTypeRef()) }
}
/// Returns the object as a wrapped `CFType`. Consumes self and avoids changing the reference
/// count.
#[inline]
fn into_CFType(self) -> CFType
where
Self: Sized,
{
let reference = self.as_CFTypeRef();
mem::forget(self);
unsafe { TCFType::wrap_under_create_rule(reference) }
}
/// Returns the object as a raw `CFTypeRef`. The reference count is not adjusted.
fn as_CFTypeRef(&self) -> CFTypeRef;
/// Returns an instance of the object, wrapping the underlying `CFTypeRef` subclass. Use this
/// when following Core Foundation's "Get Rule". The reference count *is* bumped.
unsafe fn wrap_under_get_rule(reference: Self::Ref) -> Self;
/// Returns the reference count of the object. It is unwise to do anything other than test
/// whether the return value of this method is greater than zero.
#[inline]
fn retain_count(&self) -> CFIndex {
unsafe { CFGetRetainCount(self.as_CFTypeRef()) }
}
/// Returns the type ID of this object.
#[inline]
fn type_of(&self) -> CFTypeID {
unsafe { CFGetTypeID(self.as_CFTypeRef()) }
}
/// Writes a debugging version of this object on standard error.
fn show(&self) {
unsafe { CFShow(self.as_CFTypeRef()) }
}
/// Returns `true` if this value is an instance of another type.
#[inline]
fn instance_of<OtherCFType: TCFType>(&self) -> bool {
self.type_of() == OtherCFType::type_id()
}
}
impl TCFType for CFType {
type Ref = CFTypeRef;
#[inline]
fn as_concrete_TypeRef(&self) -> CFTypeRef {
self.0
}
#[inline]
unsafe fn wrap_under_get_rule(reference: CFTypeRef) -> CFType {
assert!(!reference.is_null(), "Attempted to create a NULL object.");
let reference: CFTypeRef = CFRetain(reference);
TCFType::wrap_under_create_rule(reference)
}
#[inline]
fn as_CFTypeRef(&self) -> CFTypeRef {
self.as_concrete_TypeRef()
}
#[inline]
unsafe fn wrap_under_create_rule(obj: CFTypeRef) -> CFType {
assert!(!obj.is_null(), "Attempted to create a NULL object.");
CFType(obj)
}
#[inline]
fn type_id() -> CFTypeID {
// FIXME(pcwalton): Is this right?
0
}
}
/// A reference to an element inside a container
pub struct ItemRef<'a, T: 'a>(ManuallyDrop<T>, PhantomData<&'a T>);
impl<'a, T> Deref for ItemRef<'a, T> {
type Target = T;
fn deref(&self) -> &T {
&self.0
}
}
impl<'a, T: fmt::Debug> fmt::Debug for ItemRef<'a, T> {
fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
self.0.fmt(f)
}
}
impl<'a, T: PartialEq> PartialEq for ItemRef<'a, T> {
fn eq(&self, other: &Self) -> bool {
self.0.eq(&other.0)
}
}
/// A reference to a mutable element inside a container
pub struct ItemMutRef<'a, T: 'a>(ManuallyDrop<T>, PhantomData<&'a T>);
impl<'a, T> Deref for ItemMutRef<'a, T> {
type Target = T;
fn deref(&self) -> &T {
&self.0
}
}
impl<'a, T> DerefMut for ItemMutRef<'a, T> {
fn deref_mut(&mut self) -> &mut T {
&mut self.0
}
}
impl<'a, T: fmt::Debug> fmt::Debug for ItemMutRef<'a, T> {
fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
self.0.fmt(f)
}
}
impl<'a, T: PartialEq> PartialEq for ItemMutRef<'a, T> {
fn eq(&self, other: &Self) -> bool {
self.0.eq(&other.0)
}
}
/// A trait describing how to convert from the stored `*mut c_void` to the desired `T`
pub unsafe trait FromMutVoid {
unsafe fn from_mut_void<'a>(x: *mut c_void) -> ItemMutRef<'a, Self>
where
Self: std::marker::Sized;
}
unsafe impl FromMutVoid for u32 {
unsafe fn from_mut_void<'a>(x: *mut c_void) -> ItemMutRef<'a, Self> {
ItemMutRef(ManuallyDrop::new(x as u32), PhantomData)
}
}
unsafe impl FromMutVoid for *const c_void {
unsafe fn from_mut_void<'a>(x: *mut c_void) -> ItemMutRef<'a, Self> {
ItemMutRef(ManuallyDrop::new(x), PhantomData)
}
}
unsafe impl<T: TCFType> FromMutVoid for T {
unsafe fn from_mut_void<'a>(x: *mut c_void) -> ItemMutRef<'a, Self> {
ItemMutRef(
ManuallyDrop::new(TCFType::wrap_under_create_rule(T::Ref::from_void_ptr(x))),
PhantomData,
)
}
}
/// A trait describing how to convert from the stored `*const c_void` to the desired `T`
pub unsafe trait FromVoid {
unsafe fn from_void<'a>(x: *const c_void) -> ItemRef<'a, Self>
where
Self: std::marker::Sized;
}
unsafe impl FromVoid for u32 {
unsafe fn from_void<'a>(x: *const c_void) -> ItemRef<'a, Self> {
// Functions like CGFontCopyTableTags treat the void*'s as u32's
// so we convert by casting directly
ItemRef(ManuallyDrop::new(x as u32), PhantomData)
}
}
unsafe impl FromVoid for *const c_void {
unsafe fn from_void<'a>(x: *const c_void) -> ItemRef<'a, Self> {
ItemRef(ManuallyDrop::new(x), PhantomData)
}
}
unsafe impl<T: TCFType> FromVoid for T {
unsafe fn from_void<'a>(x: *const c_void) -> ItemRef<'a, Self> {
ItemRef(
ManuallyDrop::new(TCFType::wrap_under_create_rule(T::Ref::from_void_ptr(x))),
PhantomData,
)
}
}
/// A trait describing how to convert from the stored `*const c_void` to the desired `T`
pub unsafe trait ToVoid<T> {
fn to_void(&self) -> *const c_void;
}
unsafe impl ToVoid<*const c_void> for *const c_void {
fn to_void(&self) -> *const c_void {
*self
}
}
unsafe impl<'a> ToVoid<CFType> for &'a CFType {
fn to_void(&self) -> *const ::std::os::raw::c_void {
self.as_concrete_TypeRef().as_void_ptr()
}
}
unsafe impl ToVoid<CFType> for CFType {
fn to_void(&self) -> *const ::std::os::raw::c_void {
self.as_concrete_TypeRef().as_void_ptr()
}
}
unsafe impl ToVoid<CFType> for CFTypeRef {
fn to_void(&self) -> *const ::std::os::raw::c_void {
self.as_void_ptr()
}
}
#[cfg(test)]
mod tests {
use super::*;
use crate::boolean::CFBoolean;
use std::mem;
#[test]
fn cftype_instance_of() {
let string = CFString::from_static_string("foo");
let cftype = string.as_CFType();
assert!(cftype.instance_of::<CFString>());
assert!(!cftype.instance_of::<CFBoolean>());
}
#[test]
fn as_cftype_retain_count() {
let string = CFString::from_static_string("alongerstring");
assert_eq!(string.retain_count(), 1);
let cftype = string.as_CFType();
assert_eq!(cftype.retain_count(), 2);
mem::drop(string);
assert_eq!(cftype.retain_count(), 1);
}
#[test]
fn into_cftype_retain_count() {
let string = CFString::from_static_string("alongerstring");
assert_eq!(string.retain_count(), 1);
let cftype = string.into_CFType();
assert_eq!(cftype.retain_count(), 1);
}
#[test]
fn as_cftype_and_downcast() {
let string = CFString::from_static_string("alongerstring");
let cftype = string.as_CFType();
let string2 = cftype.downcast::<CFString>().unwrap();
assert_eq!(string2.to_string(), "alongerstring");
assert_eq!(string.retain_count(), 3);
assert_eq!(cftype.retain_count(), 3);
assert_eq!(string2.retain_count(), 3);
}
#[test]
fn into_cftype_and_downcast_into() {
let string = CFString::from_static_string("alongerstring");
let cftype = string.into_CFType();
let string2 = cftype.downcast_into::<CFString>().unwrap();
assert_eq!(string2.to_string(), "alongerstring");
assert_eq!(string2.retain_count(), 1);
}
}