libstd: add an RAII utility for sys_common::mutex::Mutex

Signed-off-by: NODA, Kai <nodakai@gmail.com>

3 files changed, 20 insertions, 36 deletions

diff --git a/src/libstd/sys/redox/args.rs b/src/libstd/sys/redox/args.rs
index 59ae2a74a6d..556ed77372e 100644
--- a/src/libstd/sys/redox/args.rs
+++ b/src/libstd/sys/redox/args.rs
@@ -73,17 +73,15 @@ mod imp {
             CStr::from_ptr(*argv.offset(i) as *const libc::c_char).to_bytes().to_vec()
         }).collect();
 
-        LOCK.lock();
+        let _guard = LOCK.lock();
         let ptr = get_global_ptr();
         assert!((*ptr).is_none());
         (*ptr) = Some(box args);
-        LOCK.unlock();
     }
 
     pub unsafe fn cleanup() {
-        LOCK.lock();
+        let _guard = LOCK.lock();
         *get_global_ptr() = None;
-        LOCK.unlock();
     }
 
     pub fn args() -> Args {
@@ -96,16 +94,14 @@ mod imp {
 
     fn clone() -> Option<Vec<Vec<u8>>> {
         unsafe {
-            LOCK.lock();
+            let _guard = LOCK.lock();
             let ptr = get_global_ptr();
-            let ret = (*ptr).as_ref().map(|s| (**s).clone());
-            LOCK.unlock();
-            return ret
+            (*ptr).as_ref().map(|s| (**s).clone())
         }
     }
 
-    fn get_global_ptr() -> *mut Option<Box<Vec<Vec<u8>>>> {
-        unsafe { mem::transmute(&GLOBAL_ARGS_PTR) }
+    unsafe fn get_global_ptr() -> *mut Option<Box<Vec<Vec<u8>>>> {
+        mem::transmute(&GLOBAL_ARGS_PTR)
     }
 
 }
diff --git a/src/libstd/sys/unix/args.rs b/src/libstd/sys/unix/args.rs
index e1c7ffc19e5..dc1dba6f2f9 100644
--- a/src/libstd/sys/unix/args.rs
+++ b/src/libstd/sys/unix/args.rs
@@ -82,17 +82,15 @@ mod imp {
     static LOCK: Mutex = Mutex::new();
 
     pub unsafe fn init(argc: isize, argv: *const *const u8) {
-        LOCK.lock();
+        let _guard = LOCK.lock();
         ARGC = argc;
         ARGV = argv;
-        LOCK.unlock();
     }
 
     pub unsafe fn cleanup() {
-        LOCK.lock();
+        let _guard = LOCK.lock();
         ARGC = 0;
         ARGV = ptr::null();
-        LOCK.unlock();
     }
 
     pub fn args() -> Args {
@@ -104,13 +102,11 @@ mod imp {
 
     fn clone() -> Vec<OsString> {
         unsafe {
-            LOCK.lock();
-            let ret = (0..ARGC).map(|i| {
+            let _guard = LOCK.lock();
+            (0..ARGC).map(|i| {
                 let cstr = CStr::from_ptr(*ARGV.offset(i) as *const libc::c_char);
                 OsStringExt::from_vec(cstr.to_bytes().to_vec())
-            }).collect();
-            LOCK.unlock();
-            return ret
+            }).collect()
         }
     }
 }
diff --git a/src/libstd/sys/unix/os.rs b/src/libstd/sys/unix/os.rs
index 4c86fddee4b..82d05f78850 100644
--- a/src/libstd/sys/unix/os.rs
+++ b/src/libstd/sys/unix/os.rs
@@ -409,10 +409,9 @@ pub unsafe fn environ() -> *mut *const *const c_char {
 /// environment variables of the current process.
 pub fn env() -> Env {
     unsafe {
-        ENV_LOCK.lock();
+        let _guard = ENV_LOCK.lock();
         let mut environ = *environ();
         if environ == ptr::null() {
-            ENV_LOCK.unlock();
             panic!("os::env() failure getting env string from OS: {}",
                    io::Error::last_os_error());
         }
@@ -423,12 +422,10 @@ pub fn env() -> Env {
             }
             environ = environ.offset(1);
         }
-        let ret = Env {
+        return Env {
             iter: result.into_iter(),
             _dont_send_or_sync_me: PhantomData,
-        };
-        ENV_LOCK.unlock();
-        return ret
+        }
     }
 
     fn parse(input: &[u8]) -> Option<(OsString, OsString)> {
@@ -452,15 +449,14 @@ pub fn getenv(k: &OsStr) -> io::Result<Option<OsString>> {
     // always None as well
     let k = CString::new(k.as_bytes())?;
     unsafe {
-        ENV_LOCK.lock();
+        let _guard = ENV_LOCK.lock();
         let s = libc::getenv(k.as_ptr()) as *const libc::c_char;
         let ret = if s.is_null() {
             None
         } else {
             Some(OsStringExt::from_vec(CStr::from_ptr(s).to_bytes().to_vec()))
         };
-        ENV_LOCK.unlock();
-        return Ok(ret)
+        Ok(ret)
     }
 }
 
@@ -469,10 +465,8 @@ pub fn setenv(k: &OsStr, v: &OsStr) -> io::Result<()> {
     let v = CString::new(v.as_bytes())?;
 
     unsafe {
-        ENV_LOCK.lock();
-        let ret = cvt(libc::setenv(k.as_ptr(), v.as_ptr(), 1)).map(|_| ());
-        ENV_LOCK.unlock();
-        return ret
+        let _guard = ENV_LOCK.lock();
+        cvt(libc::setenv(k.as_ptr(), v.as_ptr(), 1)).map(|_| ())
     }
 }
 
@@ -480,10 +474,8 @@ pub fn unsetenv(n: &OsStr) -> io::Result<()> {
     let nbuf = CString::new(n.as_bytes())?;
 
     unsafe {
-        ENV_LOCK.lock();
-        let ret = cvt(libc::unsetenv(nbuf.as_ptr())).map(|_| ());
-        ENV_LOCK.unlock();
-        return ret
+        let _guard = ENV_LOCK.lock();
+        cvt(libc::unsetenv(nbuf.as_ptr())).map(|_| ())
     }
 }