auto merge of rust-lang#10943 : fhahn/rust/issue-7313-replace-c-types…

…, r=alexcrichton

I've started working on a patch for rust-lang#7313 . So far I tried to replace C types in `src/libstd/unstable/*` and related files.

So far, I have two questions. Is there a convention for passing pointers around in `std` as Rust types? Sometimes pointers are passed around as `*c_char` (which seems to be an `*i8`), `*c_void` or `*u8`, which leads to a lot of casts. E.g: [`exchange_malloc`](https://github.com/fhahn/rust/compare/issue-7313-replace-c-types?expand=1#diff-39f44b8c3f4496abab854b3425ac1617R60) used to return a `*c_char` but the function in turn only calls `malloc_raw` which returns a `*c_void`.
Is there a specific reason for this?

The second question is about `CString` and related functions like `with_c_str`. At the moment these functions use `*c_char*`. Should I replace it with `*u8` or keep it, because it's an wrapper around classical C strings?

src/libstd/cleanup.rs

@@ -10,12 +10,11 @@
 
 #[doc(hidden)];
 
-use libc::c_void;
 use ptr;
 use unstable::intrinsics::TyDesc;
 use unstable::raw;
 
-type DropGlue<'a> = 'a |**TyDesc, *c_void|;
+type DropGlue<'a> = 'a |**TyDesc, *u8|;
 
 static RC_IMMORTAL : uint = 0x77777777;
 
@@ -107,7 +106,7 @@ pub unsafe fn annihilate() {
         stats.n_bytes_freed +=
             (*((*alloc).type_desc)).size
             + mem::size_of::<raw::Box<()>>();
-        local_free(alloc as *i8);
+        local_free(alloc as *u8);
         true
     });
 

src/libstd/local_data.rs

@@ -41,10 +41,9 @@ local_data::get(key_vector, |opt| assert_eq!(*opt.unwrap(), ~[4]));
 // magic.
 
 use cast;
-use libc;
 use prelude::*;
 use rt::task::{Task, LocalStorage};
-use util;
+use util::replace;
 
 /**
  * Indexes a task-local data slot. This pointer is used for comparison to
@@ -87,7 +86,7 @@ impl<T: 'static> LocalData for T {}
 // n.b. If TLS is used heavily in future, this could be made more efficient with
 //      a proper map.
 #[doc(hidden)]
-pub type Map = ~[Option<(*libc::c_void, TLSValue, LoanState)>];
+pub type Map = ~[Option<(*u8, TLSValue, LoanState)>];
 type TLSValue = ~LocalData;
 
 // Gets the map from the runtime. Lazily initialises if not done so already.
@@ -128,7 +127,7 @@ impl LoanState {
     }
 }
 
-fn key_to_key_value<T: 'static>(key: Key<T>) -> *libc::c_void {
+fn key_to_key_value<T: 'static>(key: Key<T>) -> *u8 {
     unsafe { cast::transmute(key) }
 }
 
@@ -151,7 +150,7 @@ pub fn pop<T: 'static>(key: Key<T>) -> Option<T> {
                 // Move the data out of the `entry` slot via util::replace.
                 // This is guaranteed to succeed because we already matched
                 // on `Some` above.
-                let data = match util::replace(entry, None) {
+                let data = match replace(entry, None) {
                     Some((_, data, _)) => data,
                     None => abort()
                 };
@@ -302,7 +301,7 @@ pub fn set<T: 'static>(key: Key<T>, data: T) {
     let data = ~data as ~LocalData:;
 
     fn insertion_position(map: &mut Map,
-                          key: *libc::c_void) -> Option<uint> {
+                          key: *u8) -> Option<uint> {
         // First see if the map contains this key already
         let curspot = map.iter().position(|entry| {
             match *entry {

src/libstd/os.rs

@@ -44,9 +44,9 @@ use unstable::finally::Finally;
 use sync::atomics::{AtomicInt, INIT_ATOMIC_INT, SeqCst};
 
 /// Delegates to the libc close() function, returning the same return value.
-pub fn close(fd: c_int) -> c_int {
+pub fn close(fd: int) -> int {
     unsafe {
-        libc::close(fd)
+        libc::close(fd as c_int) as int
     }
 }
 
@@ -57,7 +57,7 @@ static BUF_BYTES : uint = 2048u;
 pub fn getcwd() -> Path {
     use c_str::CString;
 
-    let mut buf = [0 as libc::c_char, ..BUF_BYTES];
+    let mut buf = [0 as c_char, ..BUF_BYTES];
     unsafe {
         if libc::getcwd(buf.as_mut_ptr(), buf.len() as size_t).is_null() {
             fail!()
@@ -164,7 +164,7 @@ pub fn env() -> ~[(~str,~str)] {
                        os::last_os_error());
             }
             let mut result = ~[];
-            c_str::from_c_multistring(ch as *libc::c_char, None, |cstr| {
+            c_str::from_c_multistring(ch as *c_char, None, |cstr| {
                 result.push(cstr.as_str().unwrap().to_owned());
             });
             FreeEnvironmentStringsA(ch);
@@ -173,7 +173,7 @@ pub fn env() -> ~[(~str,~str)] {
         #[cfg(unix)]
         unsafe fn get_env_pairs() -> ~[~str] {
             extern {
-                fn rust_env_pairs() -> **libc::c_char;
+                fn rust_env_pairs() -> **c_char;
             }
             let environ = rust_env_pairs();
             if environ as uint == 0 {
@@ -306,9 +306,9 @@ pub struct Pipe {
 #[cfg(unix)]
 pub fn pipe() -> Pipe {
     unsafe {
-        let mut fds = Pipe {input: 0 as c_int,
-                            out: 0 as c_int };
-        assert_eq!(libc::pipe(&mut fds.input), (0 as c_int));
+        let mut fds = Pipe {input: 0,
+                            out: 0};
+        assert_eq!(libc::pipe(&mut fds.input), 0);
         return Pipe {input: fds.input, out: fds.out};
     }
 }
@@ -321,13 +321,13 @@ pub fn pipe() -> Pipe {
         // fully understand. Here we explicitly make the pipe non-inheritable,
         // which means to pass it to a subprocess they need to be duplicated
         // first, as in std::run.
-        let mut fds = Pipe {input: 0 as c_int,
-                    out: 0 as c_int };
+        let mut fds = Pipe {input: 0,
+                    out: 0};
         let res = libc::pipe(&mut fds.input, 1024 as ::libc::c_uint,
                              (libc::O_BINARY | libc::O_NOINHERIT) as c_int);
-        assert_eq!(res, 0 as c_int);
-        assert!((fds.input != -1 as c_int && fds.input != 0 as c_int));
-        assert!((fds.out != -1 as c_int && fds.input != 0 as c_int));
+        assert_eq!(res, 0);
+        assert!((fds.input != -1 && fds.input != 0 ));
+        assert!((fds.out != -1 && fds.input != 0));
         return Pipe {input: fds.input, out: fds.out};
     }
 }
@@ -699,7 +699,7 @@ pub fn get_exit_status() -> int {
 }
 
 #[cfg(target_os = "macos")]
-unsafe fn load_argc_and_argv(argc: c_int, argv: **c_char) -> ~[~str] {
+unsafe fn load_argc_and_argv(argc: int, argv: **c_char) -> ~[~str] {
     let mut args = ~[];
     for i in range(0u, argc as uint) {
         args.push(str::raw::from_c_str(*argv.offset(i as int)));
@@ -715,7 +715,7 @@ unsafe fn load_argc_and_argv(argc: c_int, argv: **c_char) -> ~[~str] {
 #[cfg(target_os = "macos")]
 fn real_args() -> ~[~str] {
     unsafe {
-        let (argc, argv) = (*_NSGetArgc() as c_int,
+        let (argc, argv) = (*_NSGetArgc() as int,
                             *_NSGetArgv() as **c_char);
         load_argc_and_argv(argc, argv)
     }
@@ -833,7 +833,7 @@ pub struct MemoryMap {
     /// Pointer to the memory created or modified by this map.
     data: *mut u8,
     /// Number of bytes this map applies to
-    len: size_t,
+    len: uint,
     /// Type of mapping
     kind: MemoryMapKind
 }
@@ -842,7 +842,7 @@ pub struct MemoryMap {
 pub enum MemoryMapKind {
     /// Memory-mapped file. On Windows, the inner pointer is a handle to the mapping, and
     /// corresponds to `CreateFileMapping`. Elsewhere, it is null.
-    MapFile(*c_void),
+    MapFile(*u8),
     /// Virtual memory map. Usually used to change the permissions of a given chunk of memory.
     /// Corresponds to `VirtualAlloc` on Windows.
     MapVirtual
@@ -857,7 +857,7 @@ pub enum MapOption {
     /// The memory should be executable
     MapExecutable,
     /// Create a map for a specific address range. Corresponds to `MAP_FIXED` on POSIX.
-    MapAddr(*c_void),
+    MapAddr(*u8),
     /// Create a memory mapping for a file with a given fd.
     MapFd(c_int),
     /// When using `MapFd`, the start of the map is `uint` bytes from the start of the file.
@@ -881,7 +881,7 @@ pub enum MapError {
     /// using `MapFd`, the target of the fd didn't have enough resources to fulfill the request.
     ErrNoMem,
     /// Unrecognized error. The inner value is the unrecognized errno.
-    ErrUnknown(libc::c_int),
+    ErrUnknown(int),
     /// ## The following are win32-specific
     ///
     /// Unsupported combination of protection flags (`MapReadable`/`MapWritable`/`MapExecutable`).
@@ -926,12 +926,12 @@ impl MemoryMap {
     pub fn new(min_len: uint, options: &[MapOption]) -> Result<MemoryMap, MapError> {
         use libc::off_t;
 
-        let mut addr: *c_void = ptr::null();
-        let mut prot: c_int = 0;
-        let mut flags: c_int = libc::MAP_PRIVATE;
-        let mut fd: c_int = -1;
-        let mut offset: off_t = 0;
-        let len = round_up(min_len, page_size()) as size_t;
+        let mut addr: *u8 = ptr::null();
+        let mut prot = 0;
+        let mut flags = libc::MAP_PRIVATE;
+        let mut fd = -1;
+        let mut offset = 0;
+        let len = round_up(min_len, page_size());
 
         for &o in options.iter() {
             match o {
@@ -952,7 +952,7 @@ impl MemoryMap {
         if fd == -1 { flags |= libc::MAP_ANON; }
 
         let r = unsafe {
-            libc::mmap(addr, len, prot, flags, fd, offset)
+            libc::mmap(addr as *c_void, len as size_t, prot, flags, fd, offset)
         };
         if r.equiv(&libc::MAP_FAILED) {
             Err(match errno() as c_int {
@@ -961,7 +961,7 @@ impl MemoryMap {
                 libc::EINVAL => ErrUnaligned,
                 libc::ENODEV => ErrNoMapSupport,
                 libc::ENOMEM => ErrNoMem,
-                code => ErrUnknown(code)
+                code => ErrUnknown(code as int)
             })
         } else {
             Ok(MemoryMap {
@@ -987,7 +987,7 @@ impl Drop for MemoryMap {
     /// Unmap the mapping. Fails the task if `munmap` fails.
     fn drop(&mut self) {
         unsafe {
-            match libc::munmap(self.data as *c_void, self.len) {
+            match libc::munmap(self.data as *c_void, self.len as libc::size_t) {
                 0 => (),
                 -1 => match errno() as c_int {
                     libc::EINVAL => error!("invalid addr or len"),
@@ -1011,7 +1011,7 @@ impl MemoryMap {
         let mut executable = false;
         let mut fd: c_int = -1;
         let mut offset: uint = 0;
-        let len = round_up(min_len, page_size()) as SIZE_T;
+        let len = round_up(min_len, page_size());
 
         for &o in options.iter() {
             match o {
@@ -1040,7 +1040,7 @@ impl MemoryMap {
             }
             let r = unsafe {
                 libc::VirtualAlloc(lpAddress,
-                                   len,
+                                   len as SIZE_T,
                                    libc::MEM_COMMIT | libc::MEM_RESERVE,
                                    flProtect)
             };
@@ -1085,7 +1085,7 @@ impl MemoryMap {
                     _ => Ok(MemoryMap {
                        data: r as *mut u8,
                        len: len,
-                       kind: MapFile(mapping as *c_void)
+                       kind: MapFile(mapping as *u8)
                     })
                 }
             }
@@ -1116,7 +1116,7 @@ impl Drop for MemoryMap {
             match self.kind {
                 MapVirtual => {
                     if libc::VirtualFree(self.data as *mut c_void,
-                                         self.len,
+                                         self.len as size_t,
                                          libc::MEM_RELEASE) == FALSE {
                         error!("VirtualFree failed: {}", errno());
                     }

src/libstd/rc.rs

@@ -78,7 +78,7 @@ impl<T> Drop for Rc<T> {
                 if (*self.ptr).strong == 0 {
                     read_ptr(self.borrow()); // destroy the contained object
                     if (*self.ptr).weak == 0 {
-                        exchange_free(self.ptr as *mut u8 as *i8)
+                        exchange_free(self.ptr as *u8)
                     }
                 }
             }
@@ -153,7 +153,7 @@ impl<T> Drop for Weak<T> {
             if self.ptr != 0 as *mut RcBox<T> {
                 (*self.ptr).weak -= 1;
                 if (*self.ptr).weak == 0 && (*self.ptr).strong == 0 {
-                    exchange_free(self.ptr as *mut u8 as *i8)
+                    exchange_free(self.ptr as *u8)
                 }
             }
         }

src/libstd/reflect.rs

@@ -17,7 +17,6 @@ Runtime type reflection
 #[allow(missing_doc)];
 
 use unstable::intrinsics::{Disr, Opaque, TyDesc, TyVisitor};
-use libc::c_void;
 use mem;
 use unstable::raw;
 
@@ -28,7 +27,7 @@ use unstable::raw;
  * then build a MovePtrAdaptor wrapped around your struct.
  */
 pub trait MovePtr {
-    fn move_ptr(&mut self, adjustment: |*c_void| -> *c_void);
+    fn move_ptr(&mut self, adjustment: |*u8| -> *u8);
     fn push_ptr(&mut self);
     fn pop_ptr(&mut self);
 }
@@ -50,12 +49,12 @@ pub fn MovePtrAdaptor<V:TyVisitor + MovePtr>(v: V) -> MovePtrAdaptor<V> {
 impl<V:TyVisitor + MovePtr> MovePtrAdaptor<V> {
     #[inline]
     pub fn bump(&mut self, sz: uint) {
-        self.inner.move_ptr(|p| ((p as uint) + sz) as *c_void)
+        self.inner.move_ptr(|p| ((p as uint) + sz) as *u8)
     }
 
     #[inline]
     pub fn align(&mut self, a: uint) {
-        self.inner.move_ptr(|p| align(p as uint, a) as *c_void)
+        self.inner.move_ptr(|p| align(p as uint, a) as *u8)
     }
 
     #[inline]