dl_api 0.3.0

The easiest, simplest and safest way to load dynamic (shared object) libraries from Rust!
Documentation 
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// dl_api
//
// Copyright (c) 2018 Jeron A. Lau
// Copyright (c) 2017 Szymon Wieloch
// Distributed under the MIT LICENSE (See accompanying file LICENSE.txt)

use std::ffi::{CStr, CString, OsStr};
use crate::Error;

//choose the right platform implementation here
#[cfg(unix)]
use super::unix::{close_lib, get_sym, open_lib, Handle};
#[cfg(windows)]
use super::windows::{close_lib, get_sym, open_lib, Handle};

use std::mem::{size_of, transmute_copy};

#[derive(Debug)]
pub struct Library {
    handle: Handle,
}

impl Library {
    pub fn new<S>(name: S) -> Result<Library, Error>
    where
        S: AsRef<OsStr>,
    {
        Ok(Self {
            handle: unsafe { open_lib(name.as_ref()) }?,
        })
    }

    pub unsafe fn symbol<T>(&self, name: &str) -> Result<T, Error> {
        let cname = CString::new(name)?;
        self.symbol_cstr(cname.as_ref())
    }

    pub unsafe fn symbol_cstr<T>(&self, name: &CStr) -> Result<T, Error> {
        //TODO: convert it to some kind of static assertion (not yet supported in Rust)
        //this comparison should be calculated by compiler at compilation time - zero cost
        if size_of::<T>() != size_of::<*mut ()>() {
            panic!(
				"The type passed to dlopen::Library::symbol() function has a different size than a \
				 pointer - cannot transmute"
			);
        }
        let raw = get_sym(self.handle, name)?;
        if raw.is_null() {
            return Err(Error::NullSymbol);
        } else {
            Ok(transmute_copy(&raw))
        }
    }
}

impl Drop for Library {
    fn drop(&mut self) {
        self.handle = close_lib(self.handle);
    }
}

unsafe impl Sync for Library {}
unsafe impl Send for Library {}