hedera 0.8.0

The SDK for interacting with Hedera Hashgraph.
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
145
146
147
148
149
150
151

use std::{
    ptr,
    slice,
};

use libc::{
    c_void,
    size_t,
};

use crate::PublicKey;

#[repr(C)]
pub struct Signers {
    /// may only be null if signers_size is 0.
    signers: *const Signer,
    signers_size: size_t,
    /// Free this array of signers (must *not* free the contexts for the original signers)
    free: Option<unsafe extern "C" fn(signers: *const Signer, signers_size: size_t)>,
}

impl Signers {
    pub(super) fn as_slice(&self) -> &[Signer] {
        if self.signers.is_null() {
            &[]
        } else {
            unsafe { slice::from_raw_parts(self.signers, self.signers_size) }
        }
    }
}

impl Drop for Signers {
    fn drop(&mut self) {
        if let Some(free) = self.free {
            // we don't touch self after this.
            unsafe { free(self.signers, self.signers_size) }
        }
    }
}

#[repr(C)]
pub(super) struct Signer {
    /// Safety:
    /// - Must not be null
    /// - must be properly aligned
    /// - must be dereferencable in the rust sense.
    public_key: *const PublicKey,
    /// Safety: It must be safe to send `context` to other threads.
    /// Safety: It must be safe to share `context` between threads.
    context: *mut c_void,
    /// Safety:
    /// Must not be null
    /// must be callable with the appropriate arguments
    sign_func: Option<
        unsafe extern "C" fn(
            context: *mut c_void,
            message: *const u8,
            message_size: size_t,
            signature: *mut *const u8,
        ) -> size_t,
    >,
    // note: can't use typedefs in ffi apparently, cbindgen doesn't know what it
    /// Safety:
    /// Must not be null
    /// must be callable with the appropriate arguments
    free_signature_func: Option<
        unsafe extern "C" fn(context: *mut c_void, signature: *mut u8, signature_size: size_t),
    >,
    /// Safety:
    /// May be null
    /// must be callable with the appropriate arguments
    free_context_func: Option<unsafe extern "C" fn(context: *mut c_void)>,
}

impl Signer {
    pub(super) fn to_csigner(&self) -> CSigner {
        let public_key = *unsafe { self.public_key.as_ref() }.unwrap();
        let sign_func = self.sign_func.unwrap();
        let free_signature_func = self.free_signature_func.unwrap();
        CSigner {
            public_key,
            context: self.context,
            sign_func,
            free_signature_func,
            free_context_func: self.free_context_func,
        }
    }
}

/// # Safety
/// - `message` must not be freed, at all.
/// - `signature` must be non-null after returning from this function.
/// - `signature` must be valid for reads of up to the returned length bytes.
pub(super) type SignFn = unsafe extern "C" fn(
    context: *mut c_void,
    message: *const u8,
    message_size: size_t,
    signature: *mut *const u8,
) -> size_t;

pub(super) type FreeSignatureFn =
    unsafe extern "C" fn(context: *mut c_void, signature: *mut u8, signature_size: size_t);

pub(crate) struct CSigner {
    public_key: PublicKey,
    /// Safety: It must be safe to send `context` to other threads.
    /// Safety: It must be safe to share `context` between threads.
    context: *mut c_void,
    sign_func: SignFn,
    free_signature_func: FreeSignatureFn,
    free_context_func: Option<unsafe extern "C" fn(context: *mut c_void)>,
}

impl CSigner {
    pub(crate) fn public_key(&self) -> PublicKey {
        self.public_key
    }

    pub(crate) fn sign(&self, message: &[u8]) -> (PublicKey, Vec<u8>) {
        let message_size = message.len();
        let message = message.as_ptr();

        let mut signature = ptr::null();

        let signature_size = unsafe {
            (self.sign_func)(self.context, message, message_size, ptr::addr_of_mut!(signature))
        };

        assert!(!signature.is_null());
        let signature_out = unsafe { slice::from_raw_parts(signature, signature_size) }.to_vec();

        unsafe {
            (self.free_signature_func)(self.context, signature.cast_mut(), signature_size);
        }

        (self.public_key, signature_out)
    }
}

impl Drop for CSigner {
    fn drop(&mut self) {
        if let Some(free_context) = self.free_context_func {
            unsafe { free_context(self.context) }
        }
    }
}

// Safety: It must be safe to send `context` (the `*mut c_void`) to other threads.
unsafe impl Send for CSigner {}
// Safety: it must be safe to share `context` (the `*mut c_void`) between threads.
unsafe impl Sync for CSigner {}