fix fallout from std::libc separation

Author: emberian

mk/crates.mk

@@ -49,14 +49,14 @@
 # automatically generated for all stage/host/target combinations.
 ################################################################################
 
-TARGET_CRATES := std green rustuv native flate arena glob term semver \
+TARGET_CRATES := libc std green rustuv native flate arena glob term semver \
                  uuid serialize sync getopts collections num test time rand \
 		 workcache url log
 HOST_CRATES := syntax rustc rustdoc fourcc hexfloat
 CRATES := $(TARGET_CRATES) $(HOST_CRATES)
 TOOLS := compiletest rustdoc rustc
 
-DEPS_std := native:rustrt native:compiler-rt native:backtrace
+DEPS_std := libc native:rustrt native:compiler-rt native:backtrace
 DEPS_green := std rand native:context_switch
 DEPS_rustuv := std native:uv native:uv_support
 DEPS_native := std

src/doc/guide-ffi.md

@@ -12,7 +12,8 @@ The following is a minimal example of calling a foreign function which will
 compile if snappy is installed:
 
 ~~~~ {.ignore}
-use std::libc::size_t;
+extern crate libc;
+use libc::size_t;
 
 #[link(name = "snappy")]
 extern {
@@ -44,7 +45,8 @@ keeping the binding correct at runtime.
 The `extern` block can be extended to cover the entire snappy API:
 
 ~~~~ {.ignore}
-use std::libc::{c_int, size_t};
+extern crate libc;
+use libc::{c_int, size_t};
 
 #[link(name = "snappy")]
 extern {
@@ -170,6 +172,88 @@ Foreign libraries often hand off ownership of resources to the calling code.
 When this occurs, we must use Rust's destructors to provide safety and guarantee
 the release of these resources (especially in the case of failure).
 
+As an example, we give a reimplementation of owned boxes by wrapping `malloc`
+and `free`:
+
+~~~~
+extern crate libc;
+
+use std::cast;
+use libc::{c_void, size_t, malloc, free};
+use std::mem;
+use std::ptr;
+
+// Define a wrapper around the handle returned by the foreign code.
+// Unique<T> has the same semantics as ~T
+pub struct Unique<T> {
+    // It contains a single raw, mutable pointer to the object in question.
+    priv ptr: *mut T
+}
+
+// Implement methods for creating and using the values in the box.
+// NB: For simplicity and correctness, we require that T has kind Send
+// (owned boxes relax this restriction, and can contain managed (GC) boxes).
+// This is because, as implemented, the garbage collector would not know
+// about any shared boxes stored in the malloc'd region of memory.
+impl<T: Send> Unique<T> {
+    pub fn new(value: T) -> Unique<T> {
+        unsafe {
+            let ptr = malloc(std::mem::size_of::<T>() as size_t) as *mut T;
+            assert!(!ptr.is_null());
+            // `*ptr` is uninitialized, and `*ptr = value` would attempt to destroy it
+            // move_val_init moves a value into this memory without
+            // attempting to drop the original value.
+            mem::move_val_init(&mut *ptr, value);
+            Unique{ptr: ptr}
+        }
+    }
+
+    // the 'r lifetime results in the same semantics as `&*x` with ~T
+    pub fn borrow<'r>(&'r self) -> &'r T {
+        unsafe { cast::copy_lifetime(self, &*self.ptr) }
+    }
+
+    // the 'r lifetime results in the same semantics as `&mut *x` with ~T
+    pub fn borrow_mut<'r>(&'r mut self) -> &'r mut T {
+        unsafe { cast::copy_mut_lifetime(self, &mut *self.ptr) }
+    }
+}
+
+// The key ingredient for safety, we associate a destructor with
+// Unique<T>, making the struct manage the raw pointer: when the
+// struct goes out of scope, it will automatically free the raw pointer.
+// NB: This is an unsafe destructor, because rustc will not normally
+// allow destructors to be associated with parametrized types, due to
+// bad interaction with managed boxes. (With the Send restriction,
+// we don't have this problem.)
+#[unsafe_destructor]
+impl<T: Send> Drop for Unique<T> {
+    fn drop(&mut self) {
+        unsafe {
+            let x = mem::uninit(); // dummy value to swap in
+            // We need to move the object out of the box, so that
+            // the destructor is called (at the end of this scope.)
+            ptr::replace(self.ptr, x);
+            free(self.ptr as *mut c_void)
+        }
+    }
+}
+
+// A comparison between the built-in ~ and this reimplementation
+fn main() {
+    {
+        let mut x = ~5;
+        *x = 10;
+    } // `x` is freed here
+
+    {
+        let mut y = Unique::new(5);
+        *y.borrow_mut() = 10;
+    } // `y` is freed here
+}
+~~~~
+
+>>>>>>> 854a01b... fix fallout from std::libc separation
 # Callbacks from C code to Rust functions
 
 Some external libraries require the usage of callbacks to report back their
@@ -402,7 +486,7 @@ global state. In order to access these variables, you declare them in `extern`
 blocks with the `static` keyword:
 
 ~~~{.ignore}
-use std::libc;
+extern crate libc;
 
 #[link(name = "readline")]
 extern {
@@ -420,7 +504,7 @@ interface. To do this, statics can be declared with `mut` so rust can mutate
 them.
 
 ~~~{.ignore}
-use std::libc;
+extern crate libc;
 use std::ptr;
 
 #[link(name = "readline")]
@@ -444,11 +528,15 @@ calling foreign functions. Some foreign functions, most notably the Windows API,
 conventions. Rust provides a way to tell the compiler which convention to use:
 
 ~~~~
+extern crate libc;
+
 #[cfg(target_os = "win32", target_arch = "x86")]
 #[link(name = "kernel32")]
 extern "stdcall" {
-    fn SetEnvironmentVariableA(n: *u8, v: *u8) -> std::libc::c_int;
+    fn SetEnvironmentVariableA(n: *u8, v: *u8) -> libc::c_int;
 }
+
+# fn main() { }
 ~~~~
 
 This applies to the entire `extern` block. The list of supported ABI constraints

src/doc/index.md

@@ -36,6 +36,7 @@ li {list-style-type: none; }
 * [The `glob` file path matching library](glob/index.html)
 * [The `green` M:N runtime library](green/index.html)
 * [The `hexfloat` library for hexadecimal floating-point literals](hexfloat/index.html)
+* [The `libc` bindings](libc/index.html)
 * [The `native` 1:1 threading runtime](native/index.html)
 * [The `num` arbitrary precision numerics library](num/index.html)
 * [The `rand` library for random numbers and distributions](rand/index.html)

src/doc/rust.md

@@ -1471,11 +1471,13 @@ with the exception that they may not have a body
 and are instead terminated by a semicolon.
 
 ~~~~
-# use std::libc::{c_char, FILE};
+extern crate libc;
+use libc::{c_char, FILE};
 
 extern {
     fn fopen(filename: *c_char, mode: *c_char) -> *FILE;
 }
+# fn main() {}
 ~~~~
 
 Functions within external blocks may be called by Rust code,

src/etc/zsh/_rust

@@ -40,7 +40,7 @@ _rustc_opts_switches=(
 )
 _rustc_opts_lint=(
     'attribute-usage[detects bad use of attributes]'
-    'ctypes[proper use of std::libc types in foreign modules]'
+    'ctypes[proper use of libc types in foreign modules]'
     'dead-assignment[detect assignments that will never be read]'
     'dead-code[detect piece of code that will never be used]'
     'default-type-param-usage[prevents explicitly setting a type parameter with a default]'

src/libflate/lib.rs

@@ -26,13 +26,14 @@ Simple compression
 
 #[cfg(test)] #[phase(syntax, link)] extern crate log;
 
-use std::libc::{c_void, size_t, c_int};
-use std::libc;
+extern crate libc;
+
 use std::c_vec::CVec;
+use libc::{c_void, size_t, c_int};
 
-pub mod rustrt {
-    use std::libc::{c_int, c_void, size_t};
 
+pub mod rustrt {
+    use libc::{c_void, size_t, c_int};
     #[link(name = "miniz", kind = "static")]
     extern {
         pub fn tdefl_compress_mem_to_heap(psrc_buf: *c_void,

src/libgreen/lib.rs

@@ -199,6 +199,7 @@
 #[cfg(test)] #[phase(syntax, link)] extern crate log;
 #[cfg(test)] extern crate rustuv;
 extern crate rand;
+extern crate libc;
 
 use std::mem::replace;
 use std::os;

src/libgreen/macros.rs

@@ -52,7 +52,7 @@ macro_rules! rtabort (
 
 pub fn dumb_println(args: &fmt::Arguments) {
     use std::io;
-    use std::libc;
+    use libc;
 
     struct Stderr;
     impl io::Writer for Stderr {

src/libgreen/sched.rs

@@ -970,7 +970,7 @@ fn new_sched_rng() -> XorShiftRng {
 }
 #[cfg(unix)]
 fn new_sched_rng() -> XorShiftRng {
-    use std::libc;
+    use libc;
     use std::mem;
     use rand::SeedableRng;
 

src/libgreen/stack.rs

@@ -11,7 +11,7 @@
 use std::rt::env::max_cached_stacks;
 use std::os::{errno, page_size, MemoryMap, MapReadable, MapWritable,
               MapNonStandardFlags, MapVirtual};
-use std::libc;
+use libc;
 
 /// A task's stack. The name "Stack" is a vestige of segmented stacks.
 pub struct Stack {

src/liblibc/lib.rs

@@ -11,34 +11,40 @@
 #[feature(globs)];
 #[crate_id = "libc#0.10-pre"];
 #[experimental];
+#[no_std]; // we don't need std, and we can't have std, since it doesn't exist
+           // yet. std depends on us.
+#[crate_type = "rlib"];
+#[crate_type = "dylib"];
 
 /*!
 * Bindings for the C standard library and other platform libraries
 *
-* This module contains bindings to the C standard library,
-* organized into modules by their defining standard.
-* Additionally, it contains some assorted platform-specific definitions.
-* For convenience, most functions and types are reexported from `libc`,
-* so `pub use std::*` will import the available
-* C bindings as appropriate for the target platform. The exact
-* set of functions available are platform specific.
+* **NOTE:** These are *architecture and libc* specific. On Linux, these
+* bindings are only correct for glibc.
 *
-* *Note* Because these definitions are platform-specific, some may not appear in
-* the generated documentation.
+* This module contains bindings to the C standard library, organized into
+* modules by their defining standard.  Additionally, it contains some assorted
+* platform-specific definitions.  For convenience, most functions and types
+* are reexported, so `use libc::*` will import the available C bindings as
+* appropriate for the target platform. The exact set of functions available
+* are platform specific.
 *
-* We consider the following specs reasonably normative with respect
-* to interoperating with the C standard library (libc/msvcrt):
+* *Note:* Because these definitions are platform-specific, some may not appear
+* in the generated documentation.
+*
+* We consider the following specs reasonably normative with respect to
+* interoperating with the C standard library (libc/msvcrt):
 *
 * * ISO 9899:1990 ('C95', 'ANSI C', 'Standard C'), NA1, 1995.
 * * ISO 9899:1999 ('C99' or 'C9x').
 * * ISO 9945:1988 / IEEE 1003.1-1988 ('POSIX.1').
 * * ISO 9945:2001 / IEEE 1003.1-2001 ('POSIX:2001', 'SUSv3').
 * * ISO 9945:2008 / IEEE 1003.1-2008 ('POSIX:2008', 'SUSv4').
 *
-* Note that any reference to the 1996 revision of POSIX, or any revs
-* between 1990 (when '88 was approved at ISO) and 2001 (when the next
-* actual revision-revision happened), are merely additions of other
-* chapters (1b and 1c) outside the core interfaces.
+* Note that any reference to the 1996 revision of POSIX, or any revs between
+* 1990 (when '88 was approved at ISO) and 2001 (when the next actual
+* revision-revision happened), are merely additions of other chapters (1b and
+* 1c) outside the core interfaces.
 *
 * Despite having several names each, these are *reasonably* coherent
 * point-in-time, list-of-definition sorts of specs. You can get each under a
@@ -55,22 +61,26 @@
 * sanity while editing, filling-in-details and eliminating duplication) into
 * definitions common-to-all (held in modules named c95, c99, posix88, posix01
 * and posix08) and definitions that appear only on *some* platforms (named
-* 'extra'). This would be things like significant OSX foundation kit, or
-* win32 library kernel32.dll, or various fancy glibc, linux or BSD
-* extensions.
+* 'extra'). This would be things like significant OSX foundation kit, or win32
+* library kernel32.dll, or various fancy glibc, linux or BSD extensions.
 *
 * In addition to the per-platform 'extra' modules, we define a module of
 * 'common BSD' libc routines that never quite made it into POSIX but show up
-* in multiple derived systems. This is the 4.4BSD r2 / 1995 release, the
-* final one from Berkeley after the lawsuits died down and the CSRG
-* dissolved.
+* in multiple derived systems. This is the 4.4BSD r2 / 1995 release, the final
+* one from Berkeley after the lawsuits died down and the CSRG dissolved.
 */
 
 #[allow(non_camel_case_types)];
 #[allow(non_uppercase_statics)];
 #[allow(missing_doc)];
 #[allow(uppercase_variables)];
 
+#[cfg(test)] extern crate std;
+#[cfg(test)] extern crate extra;
+// for lang="start"
+#[cfg(test)] extern crate green;
+#[cfg(test)] extern crate rustuv;
+
 // Initial glob-exports mean that all the contents of all the modules
 // wind up exported, if you're interested in writing platform-specific code.
 
@@ -3862,12 +3872,11 @@ pub mod funcs {
         pub mod glob {
             use types::os::arch::c95::{c_char, c_int};
             use types::os::common::posix01::{glob_t};
-            use Nullable;
 
             extern {
                 pub fn glob(pattern: *c_char,
                             flags: c_int,
-                            errfunc: Nullable<extern "C" fn(epath: *c_char, errno: int) -> int>,
+                            errfunc: ::Nullable<extern "C" fn(epath: *c_char, errno: int) -> int>,
                             pglob: *mut glob_t);
                 pub fn globfree(pglob: *mut glob_t);
             }

src/libnative/io/addrinfo.rs

@@ -12,8 +12,8 @@ use ai = std::io::net::addrinfo;
 use std::c_str::CString;
 use std::cast;
 use std::io::IoError;
-use std::libc;
-use std::libc::{c_char, c_int};
+use libc;
+use libc::{c_char, c_int};
 use std::ptr::{null, mut_null};
 
 use super::net::sockaddr_to_addr;

src/libnative/io/file_unix.rs

@@ -14,8 +14,8 @@ use std::sync::arc::UnsafeArc;
 use std::c_str::CString;
 use std::io::IoError;
 use std::io;
-use std::libc::{c_int, c_void};
-use std::libc;
+use libc::{c_int, c_void};
+use libc;
 use std::mem;
 use std::rt::rtio;
 use std::slice;
@@ -341,8 +341,8 @@ pub fn mkdir(p: &CString, mode: io::FilePermission) -> IoResult<()> {
 }
 
 pub fn readdir(p: &CString) -> IoResult<~[Path]> {
-    use std::libc::{dirent_t};
-    use std::libc::{opendir, readdir_r, closedir};
+    use libc::{dirent_t};
+    use libc::{opendir, readdir_r, closedir};
 
     fn prune(root: &CString, dirs: ~[Path]) -> ~[Path] {
         let root = unsafe { CString::new(root.with_ref(|p| p), false) };
@@ -520,7 +520,7 @@ pub fn utime(p: &CString, atime: u64, mtime: u64) -> IoResult<()> {
 mod tests {
     use super::{CFile, FileDesc};
     use std::io;
-    use std::libc;
+    use libc;
     use std::os;
     use std::rt::rtio::RtioFileStream;