auto merge of #12445 : huonw/rust/less-unsafe, r=alexcrichton

Commits for details. Highlights:

- `flate` returns `CVec<u8>` to save reallocating a whole new `&[u8]`
- a lot of `transmute`s removed outright or replaced with `as` (etc.)

19 files changed, 68 insertions, 78 deletions

diff --git a/mk/crates.mk b/mk/crates.mk
index 8e624cb313f..9489b907b4d 100644
--- a/mk/crates.mk
+++ b/mk/crates.mk
@@ -65,7 +65,7 @@ DEPS_rustc := syntax native:rustllvm flate arena serialize sync getopts \
               collections time extra
 DEPS_rustdoc := rustc native:sundown serialize sync getopts collections \
                 test time
-DEPS_flate := std native:miniz
+DEPS_flate := std extra native:miniz
 DEPS_arena := std collections
 DEPS_glob := std
 DEPS_serialize := std
diff --git a/src/libarena/lib.rs b/src/libarena/lib.rs
index 3cf89c3124c..717e5ec7b18 100644
--- a/src/libarena/lib.rs
+++ b/src/libarena/lib.rs
@@ -167,13 +167,12 @@ unsafe fn destroy_chunk(chunk: &Chunk) {
 // is necessary in order to properly do cleanup if a failure occurs
 // during an initializer.
 #[inline]
-unsafe fn bitpack_tydesc_ptr(p: *TyDesc, is_done: bool) -> uint {
-    let p_bits: uint = transmute(p);
-    p_bits | (is_done as uint)
+fn bitpack_tydesc_ptr(p: *TyDesc, is_done: bool) -> uint {
+    p as uint | (is_done as uint)
 }
 #[inline]
-unsafe fn un_bitpack_tydesc_ptr(p: uint) -> (*TyDesc, bool) {
-    (transmute(p & !1), p & 1 == 1)
+fn un_bitpack_tydesc_ptr(p: uint) -> (*TyDesc, bool) {
+    ((p & !1) as *TyDesc, p & 1 == 1)
 }
 
 impl Arena {
diff --git a/src/libextra/c_vec.rs b/src/libextra/c_vec.rs
index fec5b105c4b..b93ffce636b 100644
--- a/src/libextra/c_vec.rs
+++ b/src/libextra/c_vec.rs
@@ -35,7 +35,9 @@
  * if necessary.
  */
 
+use std::cast;
 use std::ptr;
+use std::raw;
 
 /**
  * The type representing a foreign chunk of memory
@@ -111,6 +113,20 @@ impl <T> CVec<T> {
         }
     }
 
+    /// View the stored data as a slice.
+    pub fn as_slice<'a>(&'a self) -> &'a [T] {
+        unsafe {
+            cast::transmute(raw::Slice { data: self.base as *T, len: self.len })
+        }
+    }
+
+    /// View the stored data as a mutable slice.
+    pub fn as_mut_slice<'a>(&'a mut self) -> &'a mut [T] {
+        unsafe {
+            cast::transmute(raw::Slice { data: self.base as *T, len: self.len })
+        }
+    }
+
     /**
      * Retrieves an element at a given index
      *
diff --git a/src/libflate/lib.rs b/src/libflate/lib.rs
index d4a85b01324..1a14432be6a 100644
--- a/src/libflate/lib.rs
+++ b/src/libflate/lib.rs
@@ -20,9 +20,10 @@ Simple compression
 #[license = "MIT/ASL2"];
 #[allow(missing_doc)];
 
+extern crate extra;
 use std::libc::{c_void, size_t, c_int};
 use std::libc;
-use std::vec;
+use extra::c_vec::CVec;
 
 pub mod rustrt {
     use std::libc::{c_int, c_void, size_t};
@@ -33,13 +34,13 @@ pub mod rustrt {
                                           src_buf_len: size_t,
                                           pout_len: *mut size_t,
                                           flags: c_int)
-                                          -> *c_void;
+                                          -> *mut c_void;
 
         pub fn tinfl_decompress_mem_to_heap(psrc_buf: *c_void,
                                             src_buf_len: size_t,
                                             pout_len: *mut size_t,
                                             flags: c_int)
-                                            -> *c_void;
+                                            -> *mut c_void;
     }
 }
 
@@ -47,49 +48,43 @@ 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) -> ~[u8] {
+fn deflate_bytes_internal(bytes: &[u8], flags: c_int) -> CVec<u8> {
     unsafe {
         let mut outsz : size_t = 0;
         let res = rustrt::tdefl_compress_mem_to_heap(bytes.as_ptr() as *c_void,
                                                      bytes.len() as size_t,
                                                      &mut outsz,
                                                      flags);
-        assert!(res as int != 0);
-            let out = vec::raw::from_buf_raw(res as *u8,
-                                             outsz as uint);
-        libc::free(res as *mut c_void);
-        out
+        assert!(!res.is_null());
+        CVec::new_with_dtor(res as *mut u8, outsz as uint, proc() libc::free(res))
     }
 }
 
-pub fn deflate_bytes(bytes: &[u8]) -> ~[u8] {
+pub fn deflate_bytes(bytes: &[u8]) -> CVec<u8> {
     deflate_bytes_internal(bytes, LZ_NORM)
 }
 
-pub fn deflate_bytes_zlib(bytes: &[u8]) -> ~[u8] {
+pub fn deflate_bytes_zlib(bytes: &[u8]) -> CVec<u8> {
     deflate_bytes_internal(bytes, LZ_NORM | TDEFL_WRITE_ZLIB_HEADER)
 }
 
-fn inflate_bytes_internal(bytes: &[u8], flags: c_int) -> ~[u8] {
+fn inflate_bytes_internal(bytes: &[u8], flags: c_int) -> CVec<u8> {
     unsafe {
         let mut outsz : size_t = 0;
         let res = rustrt::tinfl_decompress_mem_to_heap(bytes.as_ptr() as *c_void,
                                                        bytes.len() as size_t,
                                                        &mut outsz,
                                                        flags);
-        assert!(res as int != 0);
-        let out = vec::raw::from_buf_raw(res as *u8,
-                                         outsz as uint);
-        libc::free(res as *mut c_void);
-        out
+        assert!(!res.is_null());
+        CVec::new_with_dtor(res as *mut u8, outsz as uint, proc() libc::free(res))
     }
 }
 
-pub fn inflate_bytes(bytes: &[u8]) -> ~[u8] {
+pub fn inflate_bytes(bytes: &[u8]) -> CVec<u8> {
     inflate_bytes_internal(bytes, 0)
 }
 
-pub fn inflate_bytes_zlib(bytes: &[u8]) -> ~[u8] {
+pub fn inflate_bytes_zlib(bytes: &[u8]) -> CVec<u8> {
     inflate_bytes_internal(bytes, TINFL_FLAG_PARSE_ZLIB_HEADER)
 }
 
@@ -115,11 +110,11 @@ mod tests {
             debug!("de/inflate of {} bytes of random word-sequences",
                    input.len());
             let cmp = deflate_bytes(input);
-            let out = inflate_bytes(cmp);
+            let out = inflate_bytes(cmp.as_slice());
             debug!("{} bytes deflated to {} ({:.1f}% size)",
                    input.len(), cmp.len(),
                    100.0 * ((cmp.len() as f64) / (input.len() as f64)));
-            assert_eq!(input, out);
+            assert_eq!(input.as_slice(), out.as_slice());
         }
     }
 
@@ -127,7 +122,7 @@ mod tests {
     fn test_zlib_flate() {
         let bytes = ~[1, 2, 3, 4, 5];
         let deflated = deflate_bytes(bytes);
-        let inflated = inflate_bytes(deflated);
-        assert_eq!(inflated, bytes);
+        let inflated = inflate_bytes(deflated.as_slice());
+        assert_eq!(inflated.as_slice(), bytes.as_slice());
     }
 }
diff --git a/src/libgreen/context.rs b/src/libgreen/context.rs
index 1d79f3f14c5..779fb6815b7 100644
--- a/src/libgreen/context.rs
+++ b/src/libgreen/context.rs
@@ -9,8 +9,7 @@
 // except according to those terms.
 
 use std::uint;
-use std::cast::{transmute, transmute_mut_unsafe,
-                transmute_region, transmute_mut_region};
+use std::cast::{transmute, transmute_mut_unsafe};
 use stack::Stack;
 use std::rt::stack;
 use std::raw;
@@ -55,10 +54,6 @@ impl Context {
         // Save and then immediately load the current context,
         // which we will then modify to call the given function when restored
         let mut regs = new_regs();
-        unsafe {
-            rust_swap_registers(transmute_mut_region(&mut *regs),
-                                transmute_region(&*regs));
-        };
 
         initialize_call_frame(&mut *regs,
                               init,
@@ -294,11 +289,8 @@ fn initialize_call_frame(regs: &mut Registers, fptr: InitFn, arg: uint,
 }
 
 fn align_down(sp: *mut uint) -> *mut uint {
-    unsafe {
-        let sp: uint = transmute(sp);
-        let sp = sp & !(16 - 1);
-        transmute::<uint, *mut uint>(sp)
-    }
+    let sp = (sp as uint) & !(16 - 1);
+    sp as *mut uint
 }
 
 // ptr::mut_offset is positive ints only
diff --git a/src/libgreen/sched.rs b/src/libgreen/sched.rs
index f722744e23d..c6db989d036 100644
--- a/src/libgreen/sched.rs
+++ b/src/libgreen/sched.rs
@@ -612,9 +612,7 @@ impl Scheduler {
                                f: |&mut Scheduler, ~GreenTask|) -> ~GreenTask {
         let f_opaque = ClosureConverter::from_fn(f);
 
-        let current_task_dupe = unsafe {
-            *cast::transmute::<&~GreenTask, &uint>(&current_task)
-        };
+        let current_task_dupe = &*current_task as *GreenTask;
 
         // The current task is placed inside an enum with the cleanup
         // function. This enum is then placed inside the scheduler.
@@ -633,13 +631,8 @@ impl Scheduler {
                 cast::transmute_mut_region(*next_task.sched.get_mut_ref());
 
             let current_task: &mut GreenTask = match sched.cleanup_job {
-                Some(CleanupJob { task: ref task, .. }) => {
-                    let task_ptr: *~GreenTask = task;
-                    cast::transmute_mut_region(*cast::transmute_mut_unsafe(task_ptr))
-                }
-                None => {
-                    rtabort!("no cleanup job");
-                }
+                Some(CleanupJob { task: ref mut task, .. }) => &mut **task,
+                None => rtabort!("no cleanup job")
             };
 
             let (current_task_context, next_task_context) =
@@ -852,7 +845,7 @@ impl Scheduler {
 
     // * Utility Functions
 
-    pub fn sched_id(&self) -> uint { unsafe { cast::transmute(self) } }
+    pub fn sched_id(&self) -> uint { self as *Scheduler as uint }
 
     pub fn run_cleanup_job(&mut self) {
         let cleanup_job = self.cleanup_job.take_unwrap();
diff --git a/src/libgreen/task.rs b/src/libgreen/task.rs
index 1d7fb64896f..bf0ea14ca87 100644
--- a/src/libgreen/task.rs
+++ b/src/libgreen/task.rs
@@ -266,7 +266,7 @@ impl GreenTask {
     // context switches
 
     pub fn as_uint(&self) -> uint {
-        unsafe { cast::transmute(self) }
+        self as *GreenTask as uint
     }
 
     pub unsafe fn from_uint(val: uint) -> ~GreenTask { cast::transmute(val) }
diff --git a/src/libnative/io/addrinfo.rs b/src/libnative/io/addrinfo.rs
index 5bdeaa17e74..ff617e5a230 100644
--- a/src/libnative/io/addrinfo.rs
+++ b/src/libnative/io/addrinfo.rs
@@ -14,7 +14,7 @@ use std::cast;
 use std::io::IoError;
 use std::libc;
 use std::libc::{c_char, c_int};
-use std::ptr::null;
+use std::ptr::{null, mut_null};
 
 use super::net::sockaddr_to_addr;
 
@@ -42,13 +42,13 @@ impl GetAddrInfoRequest {
         });
 
         let hint_ptr = hint.as_ref().map_or(null(), |x| x as *libc::addrinfo);
-        let res = null();
+        let mut res = mut_null();
 
         // Make the call
         let s = unsafe {
             let ch = if c_host.is_null() { null() } else { c_host.with_ref(|x| x) };
             let cs = if c_serv.is_null() { null() } else { c_serv.with_ref(|x| x) };
-            getaddrinfo(ch, cs, hint_ptr, &res)
+            getaddrinfo(ch, cs, hint_ptr, &mut res)
         };
 
         // Error?
@@ -74,7 +74,7 @@ impl GetAddrInfoRequest {
                     flags: (*rp).ai_flags as uint
                 });
 
-                rp = (*rp).ai_next;
+                rp = (*rp).ai_next as *mut libc::addrinfo;
             }
         }
 
@@ -86,8 +86,8 @@ impl GetAddrInfoRequest {
 
 extern "system" {
     fn getaddrinfo(node: *c_char, service: *c_char,
-                   hints: *libc::addrinfo, res: **libc::addrinfo) -> c_int;
-    fn freeaddrinfo(res: *libc::addrinfo);
+                   hints: *libc::addrinfo, res: *mut *mut libc::addrinfo) -> c_int;
+    fn freeaddrinfo(res: *mut libc::addrinfo);
     #[cfg(not(windows))]
     fn gai_strerror(errcode: c_int) -> *c_char;
     #[cfg(windows)]
diff --git a/src/libnative/io/file.rs b/src/libnative/io/file.rs
index d1d2dba383d..27430ddee97 100644
--- a/src/libnative/io/file.rs
+++ b/src/libnative/io/file.rs
@@ -91,7 +91,7 @@ impl FileDesc {
         #[cfg(not(windows))] type rlen = libc::size_t;
         let ret = retry(|| unsafe {
             libc::read(self.fd(),
-                       buf.as_ptr() as *mut libc::c_void,
+                       buf.as_mut_ptr() as *mut libc::c_void,
                        buf.len() as rlen) as libc::c_int
         });
         if ret == 0 {
diff --git a/src/libnative/io/net.rs b/src/libnative/io/net.rs
index d58e4d54342..d71f7544225 100644
--- a/src/libnative/io/net.rs
+++ b/src/libnative/io/net.rs
@@ -309,7 +309,7 @@ impl rtio::RtioTcpStream for TcpStream {
         let ret = retry(|| {
             unsafe {
                 libc::recv(self.fd(),
-                           buf.as_ptr() as *mut libc::c_void,
+                           buf.as_mut_ptr() as *mut libc::c_void,
                            buf.len() as wrlen,
                            0) as libc::c_int
             }
diff --git a/src/libnative/task.rs b/src/libnative/task.rs
index ccfc040e7df..5682697ebfc 100644
--- a/src/libnative/task.rs
+++ b/src/libnative/task.rs
@@ -186,7 +186,7 @@ impl rt::Runtime for Ops {
         cur_task.put_runtime(self as ~rt::Runtime);
 
         unsafe {
-            let cur_task_dupe = *cast::transmute::<&~Task, &uint>(&cur_task);
+            let cur_task_dupe = &*cur_task as *Task;
             let task = BlockedTask::block(cur_task);
 
             if times == 1 {
@@ -218,7 +218,7 @@ impl rt::Runtime for Ops {
                 }
             }
             // re-acquire ownership of the task
-            cur_task = cast::transmute::<uint, ~Task>(cur_task_dupe);
+            cur_task = cast::transmute(cur_task_dupe);
         }
 
         // put the task back in TLS, and everything is as it once was.
diff --git a/src/librustc/back/link.rs b/src/librustc/back/link.rs
index 89cdd4dbe77..bfc7fdb1466 100644
--- a/src/librustc/back/link.rs
+++ b/src/librustc/back/link.rs
@@ -944,7 +944,7 @@ fn link_rlib(sess: Session,
             // into the archive.
             let bc = obj_filename.with_extension("bc");
             match fs::File::open(&bc).read_to_end().and_then(|data| {
-                fs::File::create(&bc).write(flate::deflate_bytes(data))
+                fs::File::create(&bc).write(flate::deflate_bytes(data).as_slice())
             }) {
                 Ok(()) => {}
                 Err(e) => {
diff --git a/src/librustc/back/lto.rs b/src/librustc/back/lto.rs
index 75fde2fdc51..c0d18672a9b 100644
--- a/src/librustc/back/lto.rs
+++ b/src/librustc/back/lto.rs
@@ -58,7 +58,7 @@ pub fn run(sess: session::Session, llmod: ModuleRef,
         let bc = bc.expect("missing bytecode in archive!");
         let bc = time(sess.time_passes(), format!("inflate {}.bc", name), (), |_|
                       flate::inflate_bytes(bc));
-        let ptr = bc.as_ptr();
+        let ptr = bc.as_slice().as_ptr();
         debug!("linking {}", name);
         time(sess.time_passes(), format!("ll link {}", name), (), |()| unsafe {
             if !llvm::LLVMRustLinkInExternalBitcode(llmod,
diff --git a/src/librustc/metadata/cstore.rs b/src/librustc/metadata/cstore.rs
index 1a8b86b3510..ce6b5af8d0e 100644
--- a/src/librustc/metadata/cstore.rs
+++ b/src/librustc/metadata/cstore.rs
@@ -18,6 +18,7 @@ use metadata::loader;
 
 use std::cell::RefCell;
 use collections::HashMap;
+use extra::c_vec::CVec;
 use syntax::ast;
 use syntax::parse::token::IdentInterner;
 
@@ -28,7 +29,7 @@ use syntax::parse::token::IdentInterner;
 pub type cnum_map = @RefCell<HashMap<ast::CrateNum, ast::CrateNum>>;
 
 pub enum MetadataBlob {
-    MetadataVec(~[u8]),
+    MetadataVec(CVec<u8>),
     MetadataArchive(loader::ArchiveMetadata),
 }
 
diff --git a/src/librustc/middle/trans/base.rs b/src/librustc/middle/trans/base.rs
index d920378f508..5b3c18a5a93 100644
--- a/src/librustc/middle/trans/base.rs
+++ b/src/librustc/middle/trans/base.rs
@@ -2569,7 +2569,7 @@ pub fn write_metadata(cx: &CrateContext, krate: &ast::Crate) -> ~[u8] {
     let encode_parms = crate_ctxt_to_encode_parms(cx, encode_inlined_item);
     let metadata = encoder::encode_metadata(encode_parms, krate);
     let compressed = encoder::metadata_encoding_version +
-                        flate::deflate_bytes(metadata);
+                        flate::deflate_bytes(metadata).as_slice();
     let llmeta = C_bytes(compressed);
     let llconst = C_struct([llmeta], false);
     let name = format!("rust_metadata_{}_{}_{}", cx.link_meta.crateid.name,
diff --git a/src/librustuv/queue.rs b/src/librustuv/queue.rs
index da502ca72de..e998b5ca20b 100644
--- a/src/librustuv/queue.rs
+++ b/src/librustuv/queue.rs
@@ -123,7 +123,7 @@ impl QueuePool {
         unsafe {
             assert_eq!(uvll::uv_async_init(loop_.handle, handle, async_cb), 0);
             uvll::uv_unref(handle);
-            let data: *c_void = *cast::transmute::<&~QueuePool, &*c_void>(&q);
+            let data = &*q as *QueuePool as *c_void;
             uvll::set_data_for_uv_handle(handle, data);
         }
 
diff --git a/src/libserialize/ebml.rs b/src/libserialize/ebml.rs
index b7e1e5a8da7..bc9eee51753 100644
--- a/src/libserialize/ebml.rs
+++ b/src/libserialize/ebml.rs
@@ -161,9 +161,7 @@ pub mod reader {
         ];
 
         unsafe {
-            let (ptr, _): (*u8, uint) = transmute(data);
-            let ptr = ptr.offset(start as int);
-            let ptr: *i32 = transmute(ptr);
+            let ptr = data.as_ptr().offset(start as int) as *i32;
             let val = from_be32(*ptr) as u32;
 
             let i = (val >> 28u) as uint;
diff --git a/src/libstd/num/f32.rs b/src/libstd/num/f32.rs
index a4eac564ee6..a98fd31c457 100644
--- a/src/libstd/num/f32.rs
+++ b/src/libstd/num/f32.rs
@@ -350,10 +350,8 @@ impl Float for f32 {
         static EXP_MASK: u32 = 0x7f800000;
         static MAN_MASK: u32 = 0x007fffff;
 
-        match (
-            unsafe { ::cast::transmute::<f32,u32>(*self) } & MAN_MASK,
-            unsafe { ::cast::transmute::<f32,u32>(*self) } & EXP_MASK,
-        ) {
+        let bits: u32 = unsafe {::cast::transmute(*self)};
+        match (bits & MAN_MASK, bits & EXP_MASK) {
             (0, 0)        => FPZero,
             (_, 0)        => FPSubnormal,
             (0, EXP_MASK) => FPInfinite,
diff --git a/src/libstd/num/f64.rs b/src/libstd/num/f64.rs
index e6b903cbbdb..5975ce40d84 100644
--- a/src/libstd/num/f64.rs
+++ b/src/libstd/num/f64.rs
@@ -352,10 +352,8 @@ impl Float for f64 {
         static EXP_MASK: u64 = 0x7ff0000000000000;
         static MAN_MASK: u64 = 0x000fffffffffffff;
 
-        match (
-            unsafe { ::cast::transmute::<f64,u64>(*self) } & MAN_MASK,
-            unsafe { ::cast::transmute::<f64,u64>(*self) } & EXP_MASK,
-        ) {
+        let bits: u64 = unsafe {::cast::transmute(*self)};
+        match (bits & MAN_MASK, bits & EXP_MASK) {
             (0, 0)        => FPZero,
             (_, 0)        => FPSubnormal,
             (0, EXP_MASK) => FPInfinite,