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// Copyright 2016 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.

//! Evil private APIs.
//!
//! These are liable to change at any time. Use with caution!

use geometry::CGRect;
use libc::{c_int, c_uint};
use std::ptr;

pub struct CGSRegion {
    region: ffi::CGSRegionRef,
}

impl Drop for CGSRegion {
    fn drop(&mut self) {
        unsafe {
            ffi::CGSRegionRelease(self.region)
        }
    }
}

impl CGSRegion {
    #[inline]
    pub fn from_rect(rect: &CGRect) -> CGSRegion {
        unsafe {
            let mut region = ptr::null_mut();
            assert!(ffi::CGSNewRegionWithRect(rect, &mut region) == 0);
            CGSRegion {
                region: region,
            }
        }
    }

    #[inline]
    pub fn from_rects(rects: &[CGRect]) -> CGSRegion {
        unsafe {
            let mut region = ptr::null_mut();
            assert!(ffi::CGSNewRegionWithRectList(rects.as_ptr(),
                                                  rects.len() as c_uint,
                                                  &mut region) == 0);
            CGSRegion {
                region: region,
            }
        }
    }
}

/// This should always be memory-safe; the window server rejects any invalid surface IDs.
pub struct CGSSurface {
    context_id: c_uint,
    window_number: c_int,
    surface_id: c_uint,
}

impl CGSSurface {
    #[inline]
    pub fn from_ids(context_id: c_uint, window_number: c_int, surface_id: c_uint) -> CGSSurface {
        CGSSurface {
            context_id: context_id,
            window_number: window_number,
            surface_id: surface_id,
        }
    }

    #[inline]
    pub fn id(&self) -> c_uint {
        self.surface_id
    }

    #[inline]
    pub fn set_shape(&self, region: &CGSRegion) {
        unsafe {
            assert!(ffi::CGSSetSurfaceShape(self.context_id,
                                            self.window_number,
                                            self.surface_id,
                                            region.region) == 0)
        }
    }
}

mod ffi {
    use geometry::CGRect;
    use libc::{c_int, c_uint};

    // This is an enum so that we can't easily make instances of this opaque type.
    pub enum CGSRegionObject {}

    pub type CGError = OSStatus;
    pub type CGSRegionRef = *mut CGSRegionObject;
    pub type OSStatus = i32;

    #[link(name = "CoreGraphics", kind = "framework")]
    extern {
        pub fn CGSRegionRelease(region: CGSRegionRef);
        pub fn CGSNewRegionWithRect(rect: *const CGRect, outRegion: *mut CGSRegionRef) -> CGError;
        pub fn CGSNewRegionWithRectList(rects: *const CGRect,
                                        rectCount: c_uint,
                                        outRegion: *mut CGSRegionRef)
                                        -> CGError;

        pub fn CGSSetSurfaceShape(contextID: c_uint,
                                  windowNumber: c_int,
                                  surfaceID: c_uint,
                                  region: CGSRegionRef)
                                  -> CGError;
    }
}