runng 0.3.2

High-level wrapper around nng (Nanomsg-Next-Generation) aka Nanomsg2
Documentation 
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

use core::ffi::c_void;
use runng_sys::*;

/// Wraps memory allocated with `nng_alloc`.  See [nng_alloc](https://nng.nanomsg.org/man/v1.2.2/nng_alloc.3) and [nng_free](https://nng.nanomsg.org/man/v1.2.2/nng_free.3).
#[derive(Debug)]
pub struct Alloc {
    ptr: *mut c_void,
    size: usize,
}

// TODO: ideally we'd replace `*mut XXX` with Unique<>, but seems that will never stabilize:
// https://github.com/rust-lang/rust/issues/27730
// Implement Send/Sync for now...
unsafe impl Send for Alloc {}
unsafe impl Sync for Alloc {}

impl Alloc {
    pub fn with_capacity(size: usize) -> Option<Alloc> {
        unsafe {
            let ptr = nng_alloc(size);
            if ptr.is_null() {
                None
            } else {
                Some(Alloc::from_raw_parts(ptr, size))
            }
        }
    }

    pub fn new<T: Into<Vec<u8>>>(t: T) -> Option<Self> {
        let bytes = t.into();
        let mut alloc = Alloc::with_capacity(bytes.len())?;
        alloc.as_mut_slice().copy_from_slice(&bytes);
        Some(alloc)
    }

    /// Creates a new `Alloc` from a pointer and a length.
    ///
    /// # Safety
    ///
    /// Takes ownership of `ptr` and releases it when dropped.
    pub(crate) unsafe fn from_raw_parts(ptr: *mut c_void, size: usize) -> Alloc {
        Alloc { ptr, size }
    }

    pub fn as_slice(&self) -> &[u8] {
        unsafe { std::slice::from_raw_parts(self.ptr as *mut u8, self.size) }
    }

    pub fn as_mut_slice(&mut self) -> &mut [u8] {
        unsafe { std::slice::from_raw_parts_mut(self.ptr as *mut u8, self.size) }
    }

    /// Take ownership of the contained memory.  You are responsible for calling `nng_free`, or passing it to nng_send, etc.
    pub unsafe fn take(mut self) -> (*mut c_void, usize) {
        self.take_unsafe()
    }

    unsafe fn take_unsafe(&mut self) -> (*mut c_void, usize) {
        let retval = (self.ptr, self.size);
        self.ptr = std::ptr::null_mut();
        self.size = 0;
        retval
    }
}

impl AsRef<[u8]> for Alloc {
    fn as_ref(&self) -> &[u8] {
        self.as_slice()
    }
}

impl AsMut<[u8]> for Alloc {
    fn as_mut(&mut self) -> &mut [u8] {
        self.as_mut_slice()
    }
}

impl Clone for Alloc {
    fn clone(&self) -> Self {
        let src = self.as_slice();
        let mut clone = Alloc::with_capacity(src.len()).unwrap();
        let dest = clone.as_mut_slice();
        dest.copy_from_slice(src);
        clone
    }
}

impl Drop for Alloc {
    fn drop(&mut self) {
        if !self.ptr.is_null() {
            unsafe {
                let (ptr, size) = self.take_unsafe();
                nng_free(ptr, size);
            }
        }
    }
}

impl PartialEq for Alloc {
    fn eq(&self, other: &Alloc) -> bool {
        self.as_slice() == other.as_slice()
    }
}