From c7f116ec261ca0ffe79c527aca14dbcdcb8e22f3 Mon Sep 17 00:00:00 2001
From: Steven Fackler <sfackler@gmail.com>
Date: Fri, 15 Jan 2016 20:52:17 -0800
Subject: [PATCH 1/3] Mention that set_logger requires `use_std`.

---
 src/lib.rs | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/lib.rs b/src/lib.rs
index a6cf8eccd..a49d8c978 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -643,6 +643,8 @@ pub fn max_log_level() -> LogLevelFilter {
 /// This function does not typically need to be called manually. Logger
 /// implementations should provide an initialization method that calls
 /// `set_logger` internally.
+///
+/// Requires the `use_std` feature (enabled by default).
 #[cfg(feature = "use_std")]
 pub fn set_logger<M>(make_logger: M) -> Result<(), SetLoggerError>
         where M: FnOnce(MaxLogLevelFilter) -> Box<Log> {

From ec82f77c726dc6bd49bddcc3ddc36d7749d343be Mon Sep 17 00:00:00 2001
From: Steven Fackler <sfackler@gmail.com>
Date: Fri, 15 Jan 2016 20:59:21 -0800
Subject: [PATCH 2/3] Drop Option wrapper around LOGGER

Avoids an unwrap
---
 src/lib.rs | 22 ++++++++++++++++++----
 1 file changed, 18 insertions(+), 4 deletions(-)

diff --git a/src/lib.rs b/src/lib.rs
index a49d8c978..6ff01c14b 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -228,7 +228,8 @@ mod macros;
 // refcount does not necessarily monotonically decrease at this point, as new
 // log calls still increment and decrement it, but the interval in between is
 // small enough that the wait is really just for the active log calls to finish.
-static mut LOGGER: Option<*const Log> = None;
+
+static mut LOGGER: *const Log = &NopLogger;
 static STATE: AtomicUsize = ATOMIC_USIZE_INIT;
 static REFCOUNT: AtomicUsize = ATOMIC_USIZE_INIT;
 
@@ -557,6 +558,15 @@ pub trait Log: Sync+Send {
     fn log(&self, record: &LogRecord);
 }
 
+// Just used as a dummy initial value for LOGGER
+struct NopLogger;
+
+impl Log for NopLogger {
+    fn enabled(&self, _: &LogMetadata) -> bool { false }
+
+    fn log(&self, _: &LogRecord) {}
+}
+
 /// The location of a log message.
 ///
 /// # Warning
@@ -697,7 +707,7 @@ pub unsafe fn set_logger_raw<M>(make_logger: M) -> Result<(), SetLoggerError>
         return Err(SetLoggerError(()));
     }
 
-    LOGGER = Some(make_logger(MaxLogLevelFilter(())));
+    LOGGER = make_logger(MaxLogLevelFilter(()));
     STATE.store(INITIALIZED, Ordering::SeqCst);
     Ok(())
 }
@@ -731,7 +741,11 @@ pub fn shutdown_logger_raw() -> Result<*const Log, ShutdownLoggerError> {
         // FIXME add a sleep here when it doesn't involve timers
     }
 
-    Ok(unsafe { LOGGER.unwrap() })
+    unsafe {
+        let logger = LOGGER;
+        LOGGER = &NopLogger;
+        Ok(logger)
+    }
 }
 
 /// The type returned by `set_logger` if `set_logger` has already been called.
@@ -834,7 +848,7 @@ fn logger() -> Option<LoggerGuard> {
         REFCOUNT.fetch_sub(1, Ordering::SeqCst);
         None
     } else {
-        Some(LoggerGuard(unsafe { &*LOGGER.unwrap() }))
+        Some(LoggerGuard(unsafe { &*LOGGER }))
     }
 }
 

From 3cdcbd1fa5d2ca143685ffe70a9a6f93204df52a Mon Sep 17 00:00:00 2001
From: Steven Fackler <sfackler@gmail.com>
Date: Fri, 15 Jan 2016 21:13:34 -0800
Subject: [PATCH 3/3] Mention use_std dependency in log_panics docs

---
 src/lib.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/lib.rs b/src/lib.rs
index 6ff01c14b..86162e049 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -789,7 +789,7 @@ impl error::Error for ShutdownLoggerError {
 /// The format is the same as the default panic handler. The reporting module is
 /// `log::panic`.
 ///
-/// Requires the `nightly` feature.
+/// Requires the `use_std` (enabled by default) and `nightly` features.
 #[cfg(all(feature = "nightly", feature = "use_std"))]
 pub fn log_panics() {
     std::panic::set_handler(panic::log);