core-foundation-rs/base.rs

// 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
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <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::cast;
use std::libc::{c_long, c_ulong};
use std::num::Bounded;

pub type Boolean = u8;

pub type CFIndex = c_long;

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 uint {
    #[inline]
    fn to_CFIndex(self) -> CFIndex {
        let max_CFIndex: CFIndex = Bounded::max_value();
        if self > (max_CFIndex as uint) {
            fail!("value out of range")
        }
        self as CFIndex
    }
}

pub type CFOptionFlags = u32;

pub struct CFRange {
    location: CFIndex,
    length: CFIndex
}

impl CFRange {
    pub fn init(offset: CFIndex, length: CFIndex) -> CFRange {
        CFRange {
            location: offset,
            length: length,
        }
    }
}

struct __CFAllocator;

pub type CFAllocatorRef = *__CFAllocator;

struct __CFNull;

pub type CFNullRef = *__CFNull;

pub type CFHashCode = c_ulong;

pub type CFTypeID = c_ulong;

struct __CFType;

pub type CFTypeRef = *__CFType;

/// Superclass of all Core Foundation objects.
pub struct CFType {
    priv obj: CFTypeRef,
}

impl Clone for CFType {
    #[inline]
    fn clone(&self) -> CFType {
        unsafe {
            TCFType::wrap_under_get_rule(self.obj)
        }
    }
}

impl Drop for CFType {
    fn drop(&mut self) {
        unsafe {
            CFRelease(self.obj)
        }
    }
}

/// All Core Foundation types implement this trait. The type parameter `TypeRef` specifies the
/// associated Core Foundation type: e.g. for `CFType` this is `CFTypeRef`; for `CFArray` this is
/// `CFArrayRef`.
pub trait TCFType<ConcreteTypeRef> {
    /// Returns the object as its concrete TypeRef.
    fn as_concrete_TypeRef(&self) -> ConcreteTypeRef;

    /// 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: ConcreteTypeRef) -> Self;

    /// Returns the type ID for this class.
    ///
    /// FIXME(pcwalton): The dummy parameter is there to work around the current inexpressivity of
    /// the Rust language.
    fn type_id(dummy: Option<Self>) -> 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 raw `CFTypeRef`. The reference count is not adjusted.
    #[inline]
    fn as_CFTypeRef(&self) -> CFTypeRef {
        unsafe {
            cast::transmute(self.as_concrete_TypeRef())
        }
    }

    /// 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.
    #[inline]
    unsafe fn wrap_under_get_rule(reference: ConcreteTypeRef) -> Self {
        let reference: ConcreteTypeRef = cast::transmute(CFRetain(cast::transmute(reference)));
        TCFType::wrap_under_create_rule(reference)
    }

    /// 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<OtherConcreteTypeRef,OtherCFType:TCFType<OtherConcreteTypeRef>>(&self) -> bool {
        let dummy: Option<OtherCFType> = None;
        self.type_of() == TCFType::type_id(dummy)
    }

    /// Performs a checked cast to another Core Foundation type.
    #[inline]
    fn cast<OtherConcreteTypeRef,OtherCFType:TCFType<OtherConcreteTypeRef>>(&self) -> OtherCFType {
        unsafe {
            assert!(self.instance_of::<OtherConcreteTypeRef,OtherCFType>());
            TCFType::wrap_under_get_rule(cast::transmute(self.as_CFTypeRef()))
        }
    }
}

impl TCFType<CFTypeRef> for CFType {
    #[inline]
    fn as_concrete_TypeRef(&self) -> CFTypeRef {
        self.obj
    }

    #[inline]
    unsafe fn wrap_under_create_rule(obj: CFTypeRef) -> CFType {
        CFType {
            obj: obj,
        }
    }

    #[inline]
    fn type_id(_: Option<CFType>) -> CFTypeID {
        // FIXME(pcwalton): Is this right?
        0
    }

    #[inline]
    fn instance_of<OtherConcreteTypeRef,OtherCFType:TCFType<OtherConcreteTypeRef>>(&self) -> bool {
        // Since this is the root of the type hierarchy, we always answer yes.
        true
    }
}

#[link(name = "CoreFoundation", kind = "framework")]
extern {
    /*
     * CFBase.h
     */

    /* CFAllocator Reference */
    // N.B. Many CFAllocator functions and constants are omitted here.
    pub static kCFAllocatorDefault: CFAllocatorRef;
    pub static kCFAllocatorSystemDefault: CFAllocatorRef;
    pub static kCFAllocatorMalloc: CFAllocatorRef;
    pub static kCFAllocatorMallocZone: CFAllocatorRef;
    pub static kCFAllocatorNull: CFAllocatorRef;
    pub static kCFAllocatorUseContext: CFAllocatorRef;

    /* CFNull Reference */

    pub static kCFNull: CFNullRef;

    /* CFType Reference */

    //fn CFCopyDescription
    //fn CFCopyTypeIDDescription
    //fn CFEqual
    //fn CFGetAllocator
    pub fn CFGetRetainCount(cf: CFTypeRef) -> CFIndex;
    pub fn CFGetTypeID(cf: CFTypeRef) -> CFTypeID;
    pub fn CFHash(cf: CFTypeRef) -> CFHashCode;
    //fn CFMakeCollectable
    pub fn CFRelease(cf: CFTypeRef);
    pub fn CFRetain(cf: CFTypeRef) -> CFTypeRef;
    pub fn CFShow(obj: CFTypeRef);

    /* Base Utilities Reference */
    // N.B. Some things missing here.
}