1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144

// 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.

//! Core Foundation byte buffers.

pub use core_foundation_sys::data::*;
use core_foundation_sys::base::CFIndex;
use core_foundation_sys::base::{kCFAllocatorDefault};
use std::ops::Deref;
use std::slice;
use std::sync::Arc;


use base::{CFIndexConvertible, TCFType};


declare_TCFType!{
    /// A byte buffer.
    CFData, CFDataRef
}
impl_TCFType!(CFData, CFDataRef, CFDataGetTypeID);
impl_CFTypeDescription!(CFData);

impl CFData {
    /// Creates a CFData around a copy `buffer`
    pub fn from_buffer(buffer: &[u8]) -> CFData {
        unsafe {
            let data_ref = CFDataCreate(kCFAllocatorDefault,
                                        buffer.as_ptr(),
                                        buffer.len().to_CFIndex());
            TCFType::wrap_under_create_rule(data_ref)
        }
    }

    /// Creates a CFData referencing `buffer` without creating a copy
    pub fn from_arc<T: AsRef<[u8]> + Sync + Send>(buffer: Arc<T>) -> Self {
        use std::os::raw::c_void;
        use crate::base::{CFAllocator, CFAllocatorContext};

        unsafe {
            let ptr = (*buffer).as_ref().as_ptr() as *const _;
            let len = (*buffer).as_ref().len().to_CFIndex();
            let info = Arc::into_raw(buffer) as *mut c_void;

            extern "C" fn deallocate<T>(_: *mut c_void, info: *mut c_void) {
                unsafe {
                    drop(Arc::from_raw(info as *mut T));
                }
            }

            // Use a separate allocator for each allocation because
            // we need `info` to do the deallocation vs. `ptr`
            let allocator = CFAllocator::new(CFAllocatorContext {
                info,
                version: 0,
                retain: None,
                reallocate: None,
                release: None,
                copyDescription: None,
                allocate: None,
                deallocate: Some(deallocate::<T>),
                preferredSize: None,
            });
            let data_ref =
                CFDataCreateWithBytesNoCopy(kCFAllocatorDefault, ptr, len, allocator.as_CFTypeRef());
            TCFType::wrap_under_create_rule(data_ref)
        }
    }

    /// Returns a pointer to the underlying bytes in this data. Note that this byte buffer is
    /// read-only.
    #[inline]
    pub fn bytes<'a>(&'a self) -> &'a [u8] {
        unsafe {
            slice::from_raw_parts(CFDataGetBytePtr(self.0), self.len() as usize)
        }
    }

    /// Returns the length of this byte buffer.
    #[inline]
    pub fn len(&self) -> CFIndex {
        unsafe {
            CFDataGetLength(self.0)
        }
    }
}

impl Deref for CFData {
    type Target = [u8];

    #[inline]
    fn deref(&self) -> &[u8] {
        self.bytes()
    }
}

#[cfg(test)]
mod test {
    use super::CFData;
    use std::sync::Arc;

    #[test]
    fn test_data_provider() {
        let l = vec![5];
        CFData::from_arc(Arc::new(l));

        let l = vec![5];
        CFData::from_arc(Arc::new(l.into_boxed_slice()));

        // Make sure the buffer is actually dropped
        use std::sync::atomic::{AtomicBool, Ordering::SeqCst};
        struct VecWrapper {
            inner: Vec<u8>,
            dropped: Arc<AtomicBool>,
        }

        impl Drop for VecWrapper {
            fn drop(&mut self) {
                self.dropped.store(true, SeqCst)
            }
        }

        impl std::convert::AsRef<[u8]> for VecWrapper {
            fn as_ref(&self) -> &[u8] {
                &self.inner
            }
        }

        let dropped = Arc::new(AtomicBool::default());
        let l = Arc::new(VecWrapper {inner: vec![5], dropped: dropped.clone() });
        let m = l.clone();
        let dp = CFData::from_arc(l);
        drop(m);
        assert!(!dropped.load(SeqCst));
        drop(dp);
        assert!(dropped.load(SeqCst))
    }
}