DRTVWR-494: Use std::thread::id for LLThread::currentID().

LLThread::currentID() used to return a U32, a distinct unsigned value
incremented by explicitly constructing LLThread or by calling LLThread::
registerThreadID() early in a thread launched by other means. The latter
imposed an unobvious requirement on new code based on std::thread. Using
std::thread::id instead delegates to the compiler/library the problem of
distinguishing threads launched by any means.

Change lots of explicit U32 declarations. Introduce LLThread::id_t typedef to
avoid having to run around fixing uses again if we later revisit this decision.

LLMutex, which stores an LLThread::id_t, wants a distinguished value meaning
NO_THREAD, and had an enum with that name. But as std::thread::id promises
that the default-constructed value is distinct from every valid value,
NO_THREAD becomes unnecessary and goes away.

Because LLMutex now stores LLThread::id_t instead of U32, make llmutex.h
#include "llthread.h" instead of the other way around. This makes LLMutex an
incomplete type within llthread.h, so move LLThread::lockData() and
unlockData() to the .cpp file. Similarly, remove llrefcount.h's #include
"llmutex.h" to break circularity; instead forward-declare LLMutex.

It turns out that a number of source files assumed that #include "llthread.h"
would get the definition for LLMutex. Sprinkle #include "llmutex.h" as needed.

In the SAFE_SSL code in llcorehttp/httpcommon.cpp, there's an ssl_thread_id()
callback that returns an unsigned long to the SSL library. When LLThread::
currentID() was U32, we could simply return that. But std::thread::id is very
deliberately opaque, and can't be reinterpret_cast to unsigned long.
Fortunately it can be hashed because std::hash is specialized with that type.

1 files changed, 5 insertions, 9 deletions

diff --git a/indra/llcommon/llmutex.h b/indra/llcommon/llmutex.h
index 1a93c048b6..838d7d34c0 100644
--- a/indra/llcommon/llmutex.h
+++ b/indra/llcommon/llmutex.h
@@ -28,6 +28,7 @@
 #define LL_LLMUTEX_H
 
 #include "stdtypes.h"
+#include "llthread.h"
 #include <boost/noncopyable.hpp>
 
 #include "mutex.h"
@@ -44,11 +45,6 @@
 class LL_COMMON_API LLMutex
 {
 public:
-	typedef enum
-	{
-		NO_THREAD = 0xFFFFFFFF
-	} e_locking_thread;
-
 	LLMutex();
 	virtual ~LLMutex();
 	
@@ -57,15 +53,15 @@ public:
 	void unlock();		// undefined behavior when called on mutex not being held
 	bool isLocked(); 	// non-blocking, but does do a lock/unlock so not free
 	bool isSelfLocked(); //return true if locked in a same thread
-	U32 lockingThread() const; //get ID of locking thread
-	
+	LLThread::id_t lockingThread() const; //get ID of locking thread
+
 protected:
 	std::mutex			mMutex;
 	mutable U32			mCount;
-	mutable U32			mLockingThread;
+	mutable LLThread::id_t	mLockingThread;
 	
 #if MUTEX_DEBUG
-	std::map<U32, BOOL> mIsLocked;
+	std::map<LLThread::id_t, BOOL> mIsLocked;
 #endif
 };