Prototyped a dynamic library facility interface
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// Copyright 2013 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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/*!
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Dynamic library facilities.
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A simple wrapper over the platforms dynamic library facilities
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*/
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use ptr;
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use cast;
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use path;
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use libc;
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use ops::*;
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use option::*;
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use result::*;
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pub struct DynamicLibrary { priv handle: *libc::c_void }
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impl Drop for DynamicLibrary {
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fn finalize(&self) {
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match do dl::check_for_errors_in {
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unsafe {
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dl::close(self.handle)
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}
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} {
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Ok(()) => { },
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Err(str) => fail!(str)
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}
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}
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}
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impl DynamicLibrary {
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/// Lazily open a dynamic library. When passed None it gives a
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/// handle to the calling process
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pub fn open(filename: Option<&path::Path>) -> Result<DynamicLibrary, ~str> {
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let open_wrapper = |raw_ptr| {
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do dl::check_for_errors_in {
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unsafe {
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DynamicLibrary { handle: dl::open(raw_ptr) }
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}
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}
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};
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match filename {
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Some(name) => do name.to_str().as_c_str |raw_name| {
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open_wrapper(raw_name)
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},
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None => open_wrapper(ptr::null())
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}
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}
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/// Access the value at the symbol of the dynamic library
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pub unsafe fn symbol<T>(&self, symbol: &str) -> Result<T, ~str> {
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// This function should have a lifetime constraint of 'self on
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// T but that feature is still unimplemented
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do dl::check_for_errors_in {
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let symbol_value = do symbol.as_c_str |raw_string| {
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dl::symbol(self.handle, raw_string)
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};
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cast::transmute(symbol_value)
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}
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}
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}
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#[test]
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priv fn test_loading_cosine () {
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// The math library does not need to be loaded since it is already
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// statically linked in
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let libm = match DynamicLibrary::open(None) {
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Err (error) => fail!("Could not load self as module: %s", error),
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Ok (libm) => libm
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};
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// Unfortunately due to issue #6194 it is not possible to call
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// this as a C function
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let cosine: extern fn(libc::c_double) -> libc::c_double = unsafe {
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match libm.symbol("cos") {
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Err (error) => fail!("Could not load function cos: %s", error),
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Ok (cosine) => cosine
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}
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};
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let argument = 0.0;
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let expected_result = 1.0;
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let result = cosine(argument);
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if result != expected_result {
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fail!("cos(%?) != %? but equaled %? instead", argument,
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expected_result, result)
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}
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}
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#[cfg(target_os = "linux")]
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#[cfg(target_os = "android")]
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#[cfg(target_os = "macos")]
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#[cfg(target_os = "freebsd")]
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mod dl {
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use libc;
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use ptr;
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use str;
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use task;
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use result::*;
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pub unsafe fn open(filename: *libc::c_char) -> *libc::c_void {
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dlopen(filename, Lazy as libc::c_int)
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}
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pub fn check_for_errors_in<T>(f: &fn()->T) -> Result<T, ~str> {
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unsafe {
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do task::atomically {
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let _old_error = dlerror();
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let result = f();
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let last_error = dlerror();
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if ptr::null() == last_error {
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Ok(result)
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} else {
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Err(str::raw::from_c_str(last_error))
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}
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}
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}
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}
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pub unsafe fn symbol(handle: *libc::c_void, symbol: *libc::c_char) -> *libc::c_void {
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dlsym(handle, symbol)
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}
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pub unsafe fn close(handle: *libc::c_void) {
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dlclose(handle); ()
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}
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pub enum RTLD {
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Lazy = 1,
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Now = 2,
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Global = 256,
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Local = 0,
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}
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#[link_name = "dl"]
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extern {
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fn dlopen(filename: *libc::c_char, flag: libc::c_int) -> *libc::c_void;
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fn dlerror() -> *libc::c_char;
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fn dlsym(handle: *libc::c_void, symbol: *libc::c_char) -> *libc::c_void;
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fn dlclose(handle: *libc::c_void) -> libc::c_int;
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}
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}
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#[cfg(target_os = "win32")]
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mod dl {
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use os;
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use libc;
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use task;
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use result::*;
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pub unsafe fn open(filename: *libc::c_char) -> *libc::c_void {
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LoadLibrary(filename)
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}
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pub fn check_for_errors_in<T>(f: &fn()->T) -> Result<T, ~str> {
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unsafe {
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do task::atomically {
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SetLastError(0);
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let result = f();
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let error = os::errno();
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if 0 == error {
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Ok(result)
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} else {
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Err(fmt!("Error code %?", error))
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}
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}
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}
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}
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pub unsafe fn symbol(handle: *libc::c_void, symbol: *libc::c_char) -> *libc::c_void {
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GetProcAddress(handle, symbol)
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}
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pub unsafe fn close(handle: *libc::c_void) {
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FreeLibrary(handle); ()
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}
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#[link_name = "kernel32"]
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extern "stdcall" {
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fn SetLastError(error: u32);
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fn LoadLibrary(name: *libc::c_char) -> *libc::c_void;
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fn GetProcAddress(handle: *libc::c_void, name: *libc::c_char) -> *libc::c_void;
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fn FreeLibrary(handle: *libc::c_void);
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}
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}
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@ -17,6 +17,14 @@ use prelude::*;
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use task;
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pub mod at_exit;
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// Currently only works for *NIXes
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#[cfg(target_os = "linux")]
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#[cfg(target_os = "android")]
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#[cfg(target_os = "macos")]
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#[cfg(target_os = "freebsd")]
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pub mod dynamic_lib;
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pub mod global;
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pub mod finally;
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pub mod weak_task;
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