Add ToCStr method .with_c_str()

.with_c_str() is a replacement for the old .as_c_str(), to avoid
unnecessary boilerplate.

Replace all usages of .to_c_str().with_ref() with .with_c_str().

13 files changed, 76 insertions, 53 deletions

diff --git a/src/libstd/c_str.rs b/src/libstd/c_str.rs
index 5c77aa4a65a..e60e9ca8a74 100644
--- a/src/libstd/c_str.rs
+++ b/src/libstd/c_str.rs
@@ -133,6 +133,29 @@ pub trait ToCStr {
 
     /// Unsafe variant of `to_c_str()` that doesn't check for nulls.
     unsafe fn to_c_str_unchecked(&self) -> CString;
+
+    /// Work with a temporary CString constructed from the receiver.
+    /// The provided `*libc::c_char` will be freed immediately upon return.
+    ///
+    /// # Example
+    ///
+    /// ~~~ {.rust}
+    /// let s = "PATH".with_c_str(|path| libc::getenv(path))
+    /// ~~~
+    ///
+    /// # Failure
+    ///
+    /// Raises the `null_byte` condition if the receiver has an interior null.
+    #[inline]
+    fn with_c_str<T>(&self, f: &fn(*libc::c_char) -> T) -> T {
+        self.to_c_str().with_ref(f)
+    }
+
+    /// Unsafe variant of `with_c_str()` that doesn't check for nulls.
+    #[inline]
+    unsafe fn with_c_str_unchecked<T>(&self, f: &fn(*libc::c_char) -> T) -> T {
+        self.to_c_str_unchecked().with_ref(f)
+    }
 }
 
 impl<'self> ToCStr for &'self str {
diff --git a/src/libstd/io.rs b/src/libstd/io.rs
index 2c18bd272e8..c9e0c4f862d 100644
--- a/src/libstd/io.rs
+++ b/src/libstd/io.rs
@@ -1041,8 +1041,8 @@ pub fn stdin() -> @Reader {
 }
 
 pub fn file_reader(path: &Path) -> Result<@Reader, ~str> {
-    let f = do path.to_c_str().with_ref |pathbuf| {
-        do "rb".to_c_str().with_ref |modebuf| {
+    let f = do path.with_c_str |pathbuf| {
+        do "rb".with_c_str |modebuf| {
             unsafe { libc::fopen(pathbuf, modebuf as *libc::c_char) }
         }
     };
@@ -1291,7 +1291,7 @@ pub fn mk_file_writer(path: &Path, flags: &[FileFlag])
         }
     }
     let fd = unsafe {
-        do path.to_c_str().with_ref |pathbuf| {
+        do path.with_c_str |pathbuf| {
             libc::open(pathbuf, fflags, (S_IRUSR | S_IWUSR) as c_int)
         }
     };
@@ -1574,8 +1574,8 @@ pub fn file_writer(path: &Path, flags: &[FileFlag]) -> Result<@Writer, ~str> {
 // FIXME: fileflags // #2004
 pub fn buffered_file_writer(path: &Path) -> Result<@Writer, ~str> {
     unsafe {
-        let f = do path.to_c_str().with_ref |pathbuf| {
-            do "w".to_c_str().with_ref |modebuf| {
+        let f = do path.with_c_str |pathbuf| {
+            do "w".with_c_str |modebuf| {
                 libc::fopen(pathbuf, modebuf)
             }
         };
diff --git a/src/libstd/os.rs b/src/libstd/os.rs
index c916be79c53..b357489d62f 100644
--- a/src/libstd/os.rs
+++ b/src/libstd/os.rs
@@ -239,7 +239,7 @@ pub fn env() -> ~[(~str,~str)] {
 pub fn getenv(n: &str) -> Option<~str> {
     unsafe {
         do with_env_lock {
-            let s = do n.to_c_str().with_ref |buf| {
+            let s = do n.with_c_str |buf| {
                 libc::getenv(buf)
             };
             if s.is_null() {
@@ -274,8 +274,8 @@ pub fn getenv(n: &str) -> Option<~str> {
 pub fn setenv(n: &str, v: &str) {
     unsafe {
         do with_env_lock {
-            do n.to_c_str().with_ref |nbuf| {
-                do v.to_c_str().with_ref |vbuf| {
+            do n.with_c_str |nbuf| {
+                do v.with_c_str |vbuf| {
                     libc::funcs::posix01::unistd::setenv(nbuf, vbuf, 1);
                 }
             }
@@ -306,7 +306,7 @@ pub fn unsetenv(n: &str) {
     fn _unsetenv(n: &str) {
         unsafe {
             do with_env_lock {
-                do n.to_c_str().with_ref |nbuf| {
+                do n.with_c_str |nbuf| {
                     libc::funcs::posix01::unistd::unsetenv(nbuf);
                 }
             }
@@ -328,7 +328,7 @@ pub fn unsetenv(n: &str) {
 }
 
 pub fn fdopen(fd: c_int) -> *FILE {
-    do "r".to_c_str().with_ref |modebuf| {
+    do "r".with_c_str |modebuf| {
         unsafe {
             libc::fdopen(fd, modebuf)
         }
@@ -464,7 +464,7 @@ pub fn self_exe_path() -> Option<Path> {
             let mut path = [0 as c_char, .. TMPBUF_SZ];
 
             do path.as_mut_buf |buf, len| {
-                let len = do "/proc/self/exe".to_c_str().with_ref |proc_self_buf| {
+                let len = do "/proc/self/exe".with_c_str |proc_self_buf| {
                     readlink(proc_self_buf, buf, len as size_t) as uint
                 };
 
@@ -593,7 +593,7 @@ pub fn walk_dir(p: &Path, f: &fn(&Path) -> bool) -> bool {
 /// Indicates whether a path represents a directory
 pub fn path_is_dir(p: &Path) -> bool {
     unsafe {
-        do p.to_c_str().with_ref |buf| {
+        do p.with_c_str |buf| {
             rustrt::rust_path_is_dir(buf) != 0 as c_int
         }
     }
@@ -602,7 +602,7 @@ pub fn path_is_dir(p: &Path) -> bool {
 /// Indicates whether a path exists
 pub fn path_exists(p: &Path) -> bool {
     unsafe {
-        do p.to_c_str().with_ref |buf| {
+        do p.with_c_str |buf| {
             rustrt::rust_path_exists(buf) != 0 as c_int
         }
     }
@@ -645,7 +645,7 @@ pub fn make_dir(p: &Path, mode: c_int) -> bool {
 
     #[cfg(unix)]
     fn mkdir(p: &Path, mode: c_int) -> bool {
-        do p.to_c_str().with_ref |buf| {
+        do p.with_c_str |buf| {
             unsafe {
                 libc::mkdir(buf, mode as libc::mode_t) == (0 as c_int)
             }
@@ -697,7 +697,7 @@ pub fn list_dir(p: &Path) -> ~[~str] {
             let mut strings = ~[];
             debug!("os::list_dir -- BEFORE OPENDIR");
 
-            let dir_ptr = do p.to_c_str().with_ref |buf| {
+            let dir_ptr = do p.with_c_str |buf| {
                 opendir(buf)
             };
 
@@ -819,7 +819,7 @@ pub fn remove_dir(p: &Path) -> bool {
 
     #[cfg(unix)]
     fn rmdir(p: &Path) -> bool {
-        do p.to_c_str().with_ref |buf| {
+        do p.with_c_str |buf| {
             unsafe {
                 libc::rmdir(buf) == (0 as c_int)
             }
@@ -844,7 +844,7 @@ pub fn change_dir(p: &Path) -> bool {
 
     #[cfg(unix)]
     fn chdir(p: &Path) -> bool {
-        do p.to_c_str().with_ref |buf| {
+        do p.with_c_str |buf| {
             unsafe {
                 libc::chdir(buf) == (0 as c_int)
             }
@@ -872,8 +872,8 @@ pub fn copy_file(from: &Path, to: &Path) -> bool {
     #[cfg(unix)]
     fn do_copy_file(from: &Path, to: &Path) -> bool {
         unsafe {
-            let istream = do from.to_c_str().with_ref |fromp| {
-                do "rb".to_c_str().with_ref |modebuf| {
+            let istream = do from.with_c_str |fromp| {
+                do "rb".with_c_str |modebuf| {
                     libc::fopen(fromp, modebuf)
                 }
             };
@@ -884,8 +884,8 @@ pub fn copy_file(from: &Path, to: &Path) -> bool {
             let from_mode = from.get_mode().expect("copy_file: couldn't get permissions \
                                                     for source file");
 
-            let ostream = do to.to_c_str().with_ref |top| {
-                do "w+b".to_c_str().with_ref |modebuf| {
+            let ostream = do to.with_c_str |top| {
+                do "w+b".with_c_str |modebuf| {
                     libc::fopen(top, modebuf)
                 }
             };
@@ -917,7 +917,7 @@ pub fn copy_file(from: &Path, to: &Path) -> bool {
             fclose(ostream);
 
             // Give the new file the old file's permissions
-            if do to.to_c_str().with_ref |to_buf| {
+            if do to.with_c_str |to_buf| {
                 libc::chmod(to_buf, from_mode as libc::mode_t)
             } != 0 {
                 return false; // should be a condition...
@@ -944,7 +944,7 @@ pub fn remove_file(p: &Path) -> bool {
     #[cfg(unix)]
     fn unlink(p: &Path) -> bool {
         unsafe {
-            do p.to_c_str().with_ref |buf| {
+            do p.with_c_str |buf| {
                 libc::unlink(buf) == (0 as c_int)
             }
         }
@@ -1282,7 +1282,7 @@ pub fn glob(pattern: &str) -> ~[Path] {
     }
 
     let mut g = default_glob_t();
-    do pattern.to_c_str().with_ref |c_pattern| {
+    do pattern.with_c_str |c_pattern| {
         unsafe { libc::glob(c_pattern, 0, ptr::null(), &mut g) }
     };
     do(|| {
@@ -1929,14 +1929,14 @@ mod tests {
             let out = tempdir.push("out.txt");
 
             /* Write the temp input file */
-            let ostream = do input.to_c_str().with_ref |fromp| {
-                do "w+b".to_c_str().with_ref |modebuf| {
+            let ostream = do input.with_c_str |fromp| {
+                do "w+b".with_c_str |modebuf| {
                     libc::fopen(fromp, modebuf)
                 }
             };
             assert!((ostream as uint != 0u));
             let s = ~"hello";
-            do "hello".to_c_str().with_ref |buf| {
+            do "hello".with_c_str |buf| {
                 let write_len = libc::fwrite(buf as *c_void,
                                              1u as size_t,
                                              (s.len() + 1u) as size_t,
@@ -2013,11 +2013,11 @@ mod tests {
         remove_file(&path);
 
         let fd = unsafe {
-            let fd = do path.to_c_str().with_ref |path| {
+            let fd = do path.with_c_str |path| {
                 open(path, O_CREAT | O_RDWR | O_TRUNC, S_IRUSR | S_IWUSR)
             };
             lseek_(fd, size);
-            do "x".to_c_str().with_ref |x| {
+            do "x".with_c_str |x| {
                 assert!(write(fd, x as *c_void, 1) == 1);
             }
             fd
diff --git a/src/libstd/path.rs b/src/libstd/path.rs
index 7f53ddf6e79..de7658b5710 100644
--- a/src/libstd/path.rs
+++ b/src/libstd/path.rs
@@ -381,7 +381,7 @@ mod stat {
 #[cfg(target_os = "win32")]
 impl WindowsPath {
     pub fn stat(&self) -> Option<libc::stat> {
-        do self.to_c_str().with_ref |buf| {
+        do self.with_c_str |buf| {
             let mut st = stat::arch::default_stat();
             match unsafe { libc::stat(buf, &mut st) } {
                 0 => Some(st),
@@ -415,7 +415,7 @@ impl WindowsPath {
 #[cfg(not(target_os = "win32"))]
 impl PosixPath {
     pub fn stat(&self) -> Option<libc::stat> {
-        do self.to_c_str().with_ref |buf| {
+        do self.with_c_str |buf| {
             let mut st = stat::arch::default_stat();
             match unsafe { libc::stat(buf as *libc::c_char, &mut st) } {
                 0 => Some(st),
@@ -493,7 +493,7 @@ impl PosixPath {
 #[cfg(unix)]
 impl PosixPath {
     pub fn lstat(&self) -> Option<libc::stat> {
-        do self.to_c_str().with_ref |buf| {
+        do self.with_c_str |buf| {
             let mut st = stat::arch::default_stat();
             match unsafe { libc::lstat(buf, &mut st) } {
                 0 => Some(st),
diff --git a/src/libstd/ptr.rs b/src/libstd/ptr.rs
index b13d46d540d..9ea56a2e931 100644
--- a/src/libstd/ptr.rs
+++ b/src/libstd/ptr.rs
@@ -481,7 +481,7 @@ pub mod ptr_tests {
     fn test_position() {
         use libc::c_char;
 
-        do "hello".to_c_str().with_ref |p| {
+        do "hello".with_c_str |p| {
             unsafe {
                 assert!(2u == position(p, |c| *c == 'l' as c_char));
                 assert!(4u == position(p, |c| *c == 'o' as c_char));
@@ -492,9 +492,9 @@ pub mod ptr_tests {
 
     #[test]
     fn test_buf_len() {
-        do "hello".to_c_str().with_ref |p0| {
-            do "there".to_c_str().with_ref |p1| {
-                do "thing".to_c_str().with_ref |p2| {
+        do "hello".with_c_str |p0| {
+            do "there".with_c_str |p1| {
+                do "thing".with_c_str |p2| {
                     let v = ~[p0, p1, p2, null()];
                     do v.as_imm_buf |vp, len| {
                         assert_eq!(unsafe { buf_len(vp) }, 3u);
diff --git a/src/libstd/rt/borrowck.rs b/src/libstd/rt/borrowck.rs
index f620a7347a4..ba4cbc66803 100644
--- a/src/libstd/rt/borrowck.rs
+++ b/src/libstd/rt/borrowck.rs
@@ -52,7 +52,7 @@ unsafe fn fail_borrowed(box: *mut raw::Box<()>, file: *c_char, line: size_t) {
     match try_take_task_borrow_list() {
         None => { // not recording borrows
             let msg = "borrowed";
-            do msg.to_c_str().with_ref |msg_p| {
+            do msg.with_c_str |msg_p| {
                 sys::begin_unwind_(msg_p, file, line);
             }
         }
@@ -68,7 +68,7 @@ unsafe fn fail_borrowed(box: *mut raw::Box<()>, file: *c_char, line: size_t) {
                     sep = " and at ";
                 }
             }
-            do msg.to_c_str().with_ref |msg_p| {
+            do msg.with_c_str |msg_p| {
                 sys::begin_unwind_(msg_p, file, line)
             }
         }
@@ -208,7 +208,7 @@ pub unsafe fn unrecord_borrow(a: *u8, old_ref_count: uint,
             let br = borrow_list.pop();
             if br.box != a || br.file != file || br.line != line {
                 let err = fmt!("wrong borrow found, br=%?", br);
-                do err.to_c_str().with_ref |msg_p| {
+                do err.with_c_str |msg_p| {
                     sys::begin_unwind_(msg_p, file, line)
                 }
             }
diff --git a/src/libstd/rt/logging.rs b/src/libstd/rt/logging.rs
index 117795f6c90..4ee65a2b449 100644
--- a/src/libstd/rt/logging.rs
+++ b/src/libstd/rt/logging.rs
@@ -66,7 +66,7 @@ pub fn init(crate_map: *u8) {
     let log_spec = os::getenv("RUST_LOG");
     match log_spec {
         Some(spec) => {
-            do spec.to_c_str().with_ref |buf| {
+            do spec.with_c_str |buf| {
                 unsafe { rust_update_log_settings(crate_map, buf) }
             }
         }
diff --git a/src/libstd/rt/uv/uvio.rs b/src/libstd/rt/uv/uvio.rs
index 038ebad3540..a26b8a3ad59 100644
--- a/src/libstd/rt/uv/uvio.rs
+++ b/src/libstd/rt/uv/uvio.rs
@@ -654,7 +654,7 @@ impl RtioUdpSocket for UvUdpSocket {
 
     fn join_multicast(&mut self, multi: IpAddr) -> Result<(), IoError> {
         let r = unsafe {
-            do multi.to_str().to_c_str().with_ref |m_addr| {
+            do multi.to_str().with_c_str |m_addr| {
                 uvll::udp_set_membership(self.native_handle(), m_addr,
                                          ptr::null(), uvll::UV_JOIN_GROUP)
             }
@@ -668,7 +668,7 @@ impl RtioUdpSocket for UvUdpSocket {
 
     fn leave_multicast(&mut self, multi: IpAddr) -> Result<(), IoError> {
         let r = unsafe {
-            do multi.to_str().to_c_str().with_ref |m_addr| {
+            do multi.to_str().with_c_str |m_addr| {
                 uvll::udp_set_membership(self.native_handle(), m_addr,
                                          ptr::null(), uvll::UV_LEAVE_GROUP)
             }
diff --git a/src/libstd/rt/uv/uvll.rs b/src/libstd/rt/uv/uvll.rs
index e240395a495..11d64f4697c 100644
--- a/src/libstd/rt/uv/uvll.rs
+++ b/src/libstd/rt/uv/uvll.rs
@@ -373,12 +373,12 @@ pub unsafe fn is_ip6_addr(addr: *sockaddr) -> bool {
 }
 
 pub unsafe fn malloc_ip4_addr(ip: &str, port: int) -> *sockaddr_in {
-    do ip.to_c_str().with_ref |ip_buf| {
+    do ip.with_c_str |ip_buf| {
         rust_uv_ip4_addrp(ip_buf as *u8, port as libc::c_int)
     }
 }
 pub unsafe fn malloc_ip6_addr(ip: &str, port: int) -> *sockaddr_in6 {
-    do ip.to_c_str().with_ref |ip_buf| {
+    do ip.with_c_str |ip_buf| {
         rust_uv_ip6_addrp(ip_buf as *u8, port as libc::c_int)
     }
 }
diff --git a/src/libstd/run.rs b/src/libstd/run.rs
index 31e317604c7..f7c684726cd 100644
--- a/src/libstd/run.rs
+++ b/src/libstd/run.rs
@@ -506,7 +506,7 @@ fn spawn_process_os(prog: &str, args: &[~str],
 
         do with_envp(env) |envp| {
             do with_dirp(dir) |dirp| {
-                do cmd.to_c_str().with_ref |cmdp| {
+                do cmd.with_c_str |cmdp| {
                     let created = CreateProcessA(ptr::null(), cast::transmute(cmdp),
                                                  ptr::mut_null(), ptr::mut_null(), TRUE,
                                                  0, envp, dirp, &mut si, &mut pi);
@@ -775,7 +775,7 @@ fn with_envp<T>(env: Option<&[(~str, ~str)]>, cb: &fn(*mut c_void) -> T) -> T {
 
 fn with_dirp<T>(d: Option<&Path>, cb: &fn(*libc::c_char) -> T) -> T {
     match d {
-      Some(dir) => dir.to_c_str().with_ref(|buf| cb(buf)),
+      Some(dir) => dir.with_c_str(|buf| cb(buf)),
       None => cb(ptr::null())
     }
 }
diff --git a/src/libstd/sys.rs b/src/libstd/sys.rs
index 03e6412fcb8..bfb9bee7802 100644
--- a/src/libstd/sys.rs
+++ b/src/libstd/sys.rs
@@ -105,8 +105,8 @@ pub trait FailWithCause {
 
 impl FailWithCause for ~str {
     fn fail_with(cause: ~str, file: &'static str, line: uint) -> ! {
-        do cause.to_c_str().with_ref |msg_buf| {
-            do file.to_c_str().with_ref |file_buf| {
+        do cause.with_c_str |msg_buf| {
+            do file.with_c_str |file_buf| {
                 begin_unwind_(msg_buf, file_buf, line as libc::size_t)
             }
         }
@@ -115,8 +115,8 @@ impl FailWithCause for ~str {
 
 impl FailWithCause for &'static str {
     fn fail_with(cause: &'static str, file: &'static str, line: uint) -> ! {
-        do cause.to_c_str().with_ref |msg_buf| {
-            do file.to_c_str().with_ref |file_buf| {
+        do cause.with_c_str |msg_buf| {
+            do file.with_c_str |file_buf| {
                 begin_unwind_(msg_buf, file_buf, line as libc::size_t)
             }
         }
diff --git a/src/libstd/unstable/dynamic_lib.rs b/src/libstd/unstable/dynamic_lib.rs
index 49e3e0777df..005cedd0ffd 100644
--- a/src/libstd/unstable/dynamic_lib.rs
+++ b/src/libstd/unstable/dynamic_lib.rs
@@ -66,7 +66,7 @@ impl DynamicLibrary {
         // T but that feature is still unimplemented
 
         let maybe_symbol_value = do dl::check_for_errors_in {
-            do symbol.to_c_str().with_ref |raw_string| {
+            do symbol.with_c_str |raw_string| {
                 dl::symbol(self.handle, raw_string)
             }
         };
@@ -145,7 +145,7 @@ mod dl {
     use result::*;
 
     pub unsafe fn open_external(filename: &path::Path) -> *libc::c_void {
-        do filename.to_c_str().with_ref |raw_name| {
+        do filename.with_c_str |raw_name| {
             dlopen(raw_name, Lazy as libc::c_int)
         }
     }
diff --git a/src/libstd/unstable/lang.rs b/src/libstd/unstable/lang.rs
index 956ffb82902..91b4283ba12 100644
--- a/src/libstd/unstable/lang.rs
+++ b/src/libstd/unstable/lang.rs
@@ -29,7 +29,7 @@ pub fn fail_bounds_check(file: *c_char, line: size_t,
                          index: size_t, len: size_t) {
     let msg = fmt!("index out of bounds: the len is %d but the index is %d",
                     len as int, index as int);
-    do msg.to_c_str().with_ref |buf| {
+    do msg.with_c_str |buf| {
         fail_(buf, file, line);
     }
 }