std: Redesign c_str and c_vec

This commit is an implementation of [RFC 494][rfc] which removes the entire
`std::c_vec` module and redesigns the `std::c_str` module as `std::ffi`.

[rfc]: https://github.com/rust-lang/rfcs/blob/master/text/0494-c_str-and-c_vec-stability.md

The interface of the new `CString` is outlined in the linked RFC, the primary
changes being:

* The `ToCStr` trait is gone, meaning the `with_c_str` and `to_c_str` methods
  are now gone. These two methods are replaced with a `CString::from_slice`
  method.
* The `CString` type is now just a wrapper around `Vec<u8>` with a static
  guarantee that there is a trailing nul byte with no internal nul bytes. This
  means that `CString` now implements `Deref<Target = [c_char]>`, which is where
  it gains most of its methods from. A few helper methods are added to acquire a
  slice of `u8` instead of `c_char`, as well as including a slice with the
  trailing nul byte if necessary.
* All usage of non-owned `CString` values is now done via two functions inside
  of `std::ffi`, called `c_str_to_bytes` and `c_str_to_bytes_with_nul`. These
  functions are now the one method used to convert a `*const c_char` to a Rust
  slice of `u8`.

Many more details, including newly deprecated methods, can be found linked in
the RFC. This is a:

[breaking-change]
Closes #20444

1 files changed, 31 insertions, 12 deletions

diff --git a/src/libflate/lib.rs b/src/libflate/lib.rs
index aa1550ae5b8..a0c9da3ae6d 100644
--- a/src/libflate/lib.rs
+++ b/src/libflate/lib.rs
@@ -21,15 +21,34 @@
 #![doc(html_logo_url = "http://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
        html_favicon_url = "http://www.rust-lang.org/favicon.ico",
        html_root_url = "http://doc.rust-lang.org/nightly/")]
-#![feature(phase, unboxed_closures)]
+#![feature(phase, unboxed_closures, associated_types)]
 
 #[cfg(test)] #[phase(plugin, link)] extern crate log;
 
 extern crate libc;
 
 use libc::{c_void, size_t, c_int};
-use std::c_vec::CVec;
+use std::ops::Deref;
 use std::ptr::Unique;
+use std::slice;
+
+pub struct Bytes {
+    ptr: Unique<u8>,
+    len: uint,
+}
+
+impl Deref for Bytes {
+    type Target = [u8];
+    fn deref(&self) -> &[u8] {
+        unsafe { slice::from_raw_mut_buf(&self.ptr.0, self.len) }
+    }
+}
+
+impl Drop for Bytes {
+    fn drop(&mut self) {
+        unsafe { libc::free(self.ptr.0 as *mut _); }
+    }
+}
 
 #[link(name = "miniz", kind = "static")]
 extern {
@@ -52,7 +71,7 @@ static LZ_NORM : c_int = 0x80;  // LZ with 128 probes, "normal"
 static TINFL_FLAG_PARSE_ZLIB_HEADER : c_int = 0x1; // parse zlib header and adler32 checksum
 static TDEFL_WRITE_ZLIB_HEADER : c_int = 0x01000; // write zlib header and adler32 checksum
 
-fn deflate_bytes_internal(bytes: &[u8], flags: c_int) -> Option<CVec<u8>> {
+fn deflate_bytes_internal(bytes: &[u8], flags: c_int) -> Option<Bytes> {
     unsafe {
         let mut outsz : size_t = 0;
         let res = tdefl_compress_mem_to_heap(bytes.as_ptr() as *const _,
@@ -60,8 +79,8 @@ fn deflate_bytes_internal(bytes: &[u8], flags: c_int) -> Option<CVec<u8>> {
                                              &mut outsz,
                                              flags);
         if !res.is_null() {
-            let res = Unique(res);
-            Some(CVec::new_with_dtor(res.0 as *mut u8, outsz as uint, move|:| libc::free(res.0)))
+            let res = Unique(res as *mut u8);
+            Some(Bytes { ptr: res, len: outsz as uint })
         } else {
             None
         }
@@ -69,16 +88,16 @@ fn deflate_bytes_internal(bytes: &[u8], flags: c_int) -> Option<CVec<u8>> {
 }
 
 /// Compress a buffer, without writing any sort of header on the output.
-pub fn deflate_bytes(bytes: &[u8]) -> Option<CVec<u8>> {
+pub fn deflate_bytes(bytes: &[u8]) -> Option<Bytes> {
     deflate_bytes_internal(bytes, LZ_NORM)
 }
 
 /// Compress a buffer, using a header that zlib can understand.
-pub fn deflate_bytes_zlib(bytes: &[u8]) -> Option<CVec<u8>> {
+pub fn deflate_bytes_zlib(bytes: &[u8]) -> Option<Bytes> {
     deflate_bytes_internal(bytes, LZ_NORM | TDEFL_WRITE_ZLIB_HEADER)
 }
 
-fn inflate_bytes_internal(bytes: &[u8], flags: c_int) -> Option<CVec<u8>> {
+fn inflate_bytes_internal(bytes: &[u8], flags: c_int) -> Option<Bytes> {
     unsafe {
         let mut outsz : size_t = 0;
         let res = tinfl_decompress_mem_to_heap(bytes.as_ptr() as *const _,
@@ -86,8 +105,8 @@ fn inflate_bytes_internal(bytes: &[u8], flags: c_int) -> Option<CVec<u8>> {
                                                &mut outsz,
                                                flags);
         if !res.is_null() {
-            let res = Unique(res);
-            Some(CVec::new_with_dtor(res.0 as *mut u8, outsz as uint, move|:| libc::free(res.0)))
+            let res = Unique(res as *mut u8);
+            Some(Bytes { ptr: res, len: outsz as uint })
         } else {
             None
         }
@@ -95,12 +114,12 @@ fn inflate_bytes_internal(bytes: &[u8], flags: c_int) -> Option<CVec<u8>> {
 }
 
 /// Decompress a buffer, without parsing any sort of header on the input.
-pub fn inflate_bytes(bytes: &[u8]) -> Option<CVec<u8>> {
+pub fn inflate_bytes(bytes: &[u8]) -> Option<Bytes> {
     inflate_bytes_internal(bytes, 0)
 }
 
 /// Decompress a buffer that starts with a zlib header.
-pub fn inflate_bytes_zlib(bytes: &[u8]) -> Option<CVec<u8>> {
+pub fn inflate_bytes_zlib(bytes: &[u8]) -> Option<Bytes> {
     inflate_bytes_internal(bytes, TINFL_FLAG_PARSE_ZLIB_HEADER)
 }