std: Move dynamic_lib from std::unstable to std

This leaves a deprecated reexport in place temporarily.

Closes #1457.

src/libstd/dynamic_lib.rs

@@ -0,0 +1,332 @@
+// Copyright 2013-2014 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// 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.
+
+/*!
+
+Dynamic library facilities.
+
+A simple wrapper over the platform's dynamic library facilities
+
+*/
+
+#![experimental]
+#![allow(missing_doc)]
+
+use clone::Clone;
+use c_str::ToCStr;
+use iter::Iterator;
+use mem;
+use ops::*;
+use option::*;
+use os;
+use path::{Path,GenericPath};
+use result::*;
+use slice::{Vector,ImmutableVector};
+use str;
+use string::String;
+use vec::Vec;
+
+pub struct DynamicLibrary { handle: *u8}
+
+impl Drop for DynamicLibrary {
+    fn drop(&mut self) {
+        match dl::check_for_errors_in(|| {
+            unsafe {
+                dl::close(self.handle)
+            }
+        }) {
+            Ok(()) => {},
+            Err(str) => fail!("{}", str)
+        }
+    }
+}
+
+impl DynamicLibrary {
+    // FIXME (#12938): Until DST lands, we cannot decompose &str into
+    // & and str, so we cannot usefully take ToCStr arguments by
+    // reference (without forcing an additional & around &str). So we
+    // are instead temporarily adding an instance for &Path, so that
+    // we can take ToCStr as owned. When DST lands, the &Path instance
+    // should be removed, and arguments bound by ToCStr should be
+    // passed by reference. (Here: in the `open` method.)
+
+    /// Lazily open a dynamic library. When passed None it gives a
+    /// handle to the calling process
+    pub fn open<T: ToCStr>(filename: Option<T>)
+                        -> Result<DynamicLibrary, String> {
+        unsafe {
+            let mut filename = filename;
+            let maybe_library = dl::check_for_errors_in(|| {
+                match filename.take() {
+                    Some(name) => dl::open_external(name),
+                    None => dl::open_internal()
+                }
+            });
+
+            // The dynamic library must not be constructed if there is
+            // an error opening the library so the destructor does not
+            // run.
+            match maybe_library {
+                Err(err) => Err(err),
+                Ok(handle) => Ok(DynamicLibrary { handle: handle })
+            }
+        }
+    }
+
+    /// Prepends a path to this process's search path for dynamic libraries
+    pub fn prepend_search_path(path: &Path) {
+        let mut search_path = DynamicLibrary::search_path();
+        search_path.insert(0, path.clone());
+        let newval = DynamicLibrary::create_path(search_path.as_slice());
+        os::setenv(DynamicLibrary::envvar(),
+                   str::from_utf8(newval.as_slice()).unwrap());
+    }
+
+    /// From a slice of paths, create a new vector which is suitable to be an
+    /// environment variable for this platforms dylib search path.
+    pub fn create_path(path: &[Path]) -> Vec<u8> {
+        let mut newvar = Vec::new();
+        for (i, path) in path.iter().enumerate() {
+            if i > 0 { newvar.push(DynamicLibrary::separator()); }
+            newvar.push_all(path.as_vec());
+        }
+        return newvar;
+    }
+
+    /// Returns the environment variable for this process's dynamic library
+    /// search path
+    pub fn envvar() -> &'static str {
+        if cfg!(windows) {
+            "PATH"
+        } else if cfg!(target_os = "macos") {
+            "DYLD_LIBRARY_PATH"
+        } else {
+            "LD_LIBRARY_PATH"
+        }
+    }
+
+    fn separator() -> u8 {
+        if cfg!(windows) {';' as u8} else {':' as u8}
+    }
+
+    /// Returns the current search path for dynamic libraries being used by this
+    /// process
+    pub fn search_path() -> Vec<Path> {
+        let mut ret = Vec::new();
+        match os::getenv_as_bytes(DynamicLibrary::envvar()) {
+            Some(env) => {
+                for portion in
+                        env.as_slice()
+                           .split(|a| *a == DynamicLibrary::separator()) {
+                    ret.push(Path::new(portion));
+                }
+            }
+            None => {}
+        }
+        return ret;
+    }
+
+    /// Access the value at the symbol of the dynamic library
+    pub unsafe fn symbol<T>(&self, symbol: &str) -> Result<T, String> {
+        // This function should have a lifetime constraint of 'a on
+        // T but that feature is still unimplemented
+
+        let maybe_symbol_value = dl::check_for_errors_in(|| {
+            symbol.with_c_str(|raw_string| {
+                dl::symbol(self.handle, raw_string)
+            })
+        });
+
+        // The value must not be constructed if there is an error so
+        // the destructor does not run.
+        match maybe_symbol_value {
+            Err(err) => Err(err),
+            Ok(symbol_value) => Ok(mem::transmute(symbol_value))
+        }
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use super::*;
+    use prelude::*;
+    use libc;
+
+    #[test]
+    #[ignore(cfg(windows))] // FIXME #8818
+    #[ignore(cfg(target_os="android"))] // FIXME(#10379)
+    fn test_loading_cosine() {
+        // The math library does not need to be loaded since it is already
+        // statically linked in
+        let none: Option<Path> = None; // appease the typechecker
+        let libm = match DynamicLibrary::open(none) {
+            Err(error) => fail!("Could not load self as module: {}", error),
+            Ok(libm) => libm
+        };
+
+        let cosine: extern fn(libc::c_double) -> libc::c_double = unsafe {
+            match libm.symbol("cos") {
+                Err(error) => fail!("Could not load function cos: {}", error),
+                Ok(cosine) => cosine
+            }
+        };
+
+        let argument = 0.0;
+        let expected_result = 1.0;
+        let result = cosine(argument);
+        if result != expected_result {
+            fail!("cos({:?}) != {:?} but equaled {:?} instead", argument,
+                   expected_result, result)
+        }
+    }
+
+    #[test]
+    #[cfg(target_os = "linux")]
+    #[cfg(target_os = "macos")]
+    #[cfg(target_os = "freebsd")]
+    fn test_errors_do_not_crash() {
+        // Open /dev/null as a library to get an error, and make sure
+        // that only causes an error, and not a crash.
+        let path = Path::new("/dev/null");
+        match DynamicLibrary::open(Some(&path)) {
+            Err(_) => {}
+            Ok(_) => fail!("Successfully opened the empty library.")
+        }
+    }
+}
+
+#[cfg(target_os = "linux")]
+#[cfg(target_os = "android")]
+#[cfg(target_os = "macos")]
+#[cfg(target_os = "freebsd")]
+pub mod dl {
+    use prelude::*;
+
+    use c_str::{CString, ToCStr};
+    use libc;
+    use ptr;
+    use result::*;
+    use str::StrAllocating;
+    use string::String;
+
+    pub unsafe fn open_external<T: ToCStr>(filename: T) -> *u8 {
+        filename.with_c_str(|raw_name| {
+            dlopen(raw_name, Lazy as libc::c_int) as *u8
+        })
+    }
+
+    pub unsafe fn open_internal() -> *u8 {
+        dlopen(ptr::null(), Lazy as libc::c_int) as *u8
+    }
+
+    pub fn check_for_errors_in<T>(f: || -> T) -> Result<T, String> {
+        use rt::mutex::{StaticNativeMutex, NATIVE_MUTEX_INIT};
+        static mut lock: StaticNativeMutex = NATIVE_MUTEX_INIT;
+        unsafe {
+            // dlerror isn't thread safe, so we need to lock around this entire
+            // sequence
+            let _guard = lock.lock();
+            let _old_error = dlerror();
+
+            let result = f();
+
+            let last_error = dlerror();
+            let ret = if ptr::null() == last_error {
+                Ok(result)
+            } else {
+                Err(CString::new(last_error, false).as_str()
+                                                   .unwrap()
+                                                   .to_string())
+            };
+
+            ret
+        }
+    }
+
+    pub unsafe fn symbol(handle: *u8, symbol: *libc::c_char) -> *u8 {
+        dlsym(handle as *libc::c_void, symbol) as *u8
+    }
+    pub unsafe fn close(handle: *u8) {
+        dlclose(handle as *libc::c_void); ()
+    }
+
+    pub enum RTLD {
+        Lazy = 1,
+        Now = 2,
+        Global = 256,
+        Local = 0,
+    }
+
+    #[link_name = "dl"]
+    extern {
+        fn dlopen(filename: *libc::c_char, flag: libc::c_int) -> *libc::c_void;
+        fn dlerror() -> *libc::c_char;
+        fn dlsym(handle: *libc::c_void, symbol: *libc::c_char) -> *libc::c_void;
+        fn dlclose(handle: *libc::c_void) -> libc::c_int;
+    }
+}
+
+#[cfg(target_os = "win32")]
+pub mod dl {
+    use c_str::ToCStr;
+    use libc;
+    use os;
+    use ptr;
+    use result::{Ok, Err, Result};
+    use str::StrAllocating;
+    use str;
+    use string::String;
+
+    pub unsafe fn open_external<T: ToCStr>(filename: T) -> *u8 {
+        // Windows expects Unicode data
+        let filename_cstr = filename.to_c_str();
+        let filename_str = str::from_utf8(filename_cstr.as_bytes_no_nul()).unwrap();
+        let filename_str = filename_str.to_utf16().append_one(0);
+        LoadLibraryW(filename_str.as_ptr() as *libc::c_void) as *u8
+    }
+
+    pub unsafe fn open_internal() -> *u8 {
+        let handle = ptr::null();
+        GetModuleHandleExW(0 as libc::DWORD, ptr::null(), &handle as **libc::c_void);
+        handle as *u8
+    }
+
+    pub fn check_for_errors_in<T>(f: || -> T) -> Result<T, String> {
+        unsafe {
+            SetLastError(0);
+
+            let result = f();
+
+            let error = os::errno();
+            if 0 == error {
+                Ok(result)
+            } else {
+                Err(format!("Error code {}", error))
+            }
+        }
+    }
+
+    pub unsafe fn symbol(handle: *u8, symbol: *libc::c_char) -> *u8 {
+        GetProcAddress(handle as *libc::c_void, symbol) as *u8
+    }
+    pub unsafe fn close(handle: *u8) {
+        FreeLibrary(handle as *libc::c_void); ()
+    }
+
+    #[allow(non_snake_case_functions)]
+    extern "system" {
+        fn SetLastError(error: libc::size_t);
+        fn LoadLibraryW(name: *libc::c_void) -> *libc::c_void;
+        fn GetModuleHandleExW(dwFlags: libc::DWORD, name: *u16,
+                              handle: **libc::c_void) -> *libc::c_void;
+        fn GetProcAddress(handle: *libc::c_void, name: *libc::c_char) -> *libc::c_void;
+        fn FreeLibrary(handle: *libc::c_void);
+    }
+}