On windows, make lock/thread function tables static

This requires us to have a separate implementation of the lock macros
that indirects to a set of functions.  Fortunately, this isn't too
hard to do.

This may be a fix for bug 3042969, where our openssl dll and our
libevent dll each got their own version of the thread stuff.

evthread-internal.h

@@ -36,7 +36,15 @@ extern "C" {
 
 struct event_base;
 
-#ifndef _EVENT_DISABLE_THREAD_SUPPORT
+#ifndef WIN32
+/* On Windows, the way we currently make DLLs, it's not allowed for us to
+ * have shared global structures.  Thus, we only do the direct-call-to-function
+ * code path if we know that the local shared library system supports it.
+ */
+#define EVTHREAD_EXPOSE_STRUCTS
+#endif
+
+#if ! defined(_EVENT_DISABLE_THREAD_SUPPORT) && defined(EVTHREAD_EXPOSE_STRUCTS)
 /* Global function pointers to lock-related functions. NULL if locking isn't
    enabled. */
 extern struct evthread_lock_callbacks _evthread_lock_fns;
@@ -92,30 +100,6 @@ extern int _evthread_lock_debugging_enabled;
 		}							\
 	} while (0)
 
-/** Acquire both lock1 and lock2.  Always allocates locks in the same order,
- * so that two threads locking two locks with LOCK2 will not deadlock. */
-#define EVLOCK_LOCK2(lock1,lock2,mode1,mode2)				\
-	do {								\
-		void *_lock1_tmplock = (lock1);				\
-		void *_lock2_tmplock = (lock2);				\
-		_EVLOCK_SORTLOCKS(_lock1_tmplock,_lock2_tmplock);	\
-		EVLOCK_LOCK(_lock1_tmplock,mode1);			\
-		if (_lock2_tmplock != _lock1_tmplock)			\
-			EVLOCK_LOCK(_lock2_tmplock,mode2);		\
-	} while (0)
-
-/** Release both lock1 and lock2.  */
-#define EVLOCK_UNLOCK2(lock1,lock2,mode1,mode2)				\
-	do {								\
-		void *_lock1_tmplock = (lock1);				\
-		void *_lock2_tmplock = (lock2);				\
-		_EVLOCK_SORTLOCKS(_lock1_tmplock,_lock2_tmplock);	\
-		if (_lock2_tmplock != _lock1_tmplock)			\
-			EVLOCK_UNLOCK(_lock2_tmplock,mode2);		\
-		EVLOCK_UNLOCK(_lock1_tmplock,mode1);			\
-	} while (0)
-
-
 /** Lock an event_base, if it is set up for locking.  Acquires the lock
     in the base structure whose field is named 'lockvar'. */
 #define EVBASE_ACQUIRE_LOCK(base, lockvar) do {				\
@@ -127,9 +111,6 @@ extern int _evthread_lock_debugging_enabled;
 		EVLOCK_UNLOCK((base)->lockvar, 0);			\
 	} while (0)
 
-int _evthread_is_debug_lock_held(void *lock);
-void *_evthread_debug_get_real_lock(void *lock);
-
 /** If lock debugging is enabled, and lock is non-null, assert that 'lock' is
  * locked and held by us. */
 #define EVLOCK_ASSERT_LOCKED(lock)					\
@@ -184,6 +165,110 @@ EVLOCK_TRY_LOCK(void *lock)
 #define EVTHREAD_COND_WAIT_TIMED(cond, lock, tv)			\
 	( (cond) ? _evthread_cond_fns.wait_condition((cond), (lock), (tv)) : 0 )
 
+#elif ! defined(_EVENT_DISABLE_THREAD_SUPPORT)
+
+unsigned long _evthreadimpl_get_id(void);
+int _evthreadimpl_is_lock_debugging_enabled(void);
+void *_evthreadimpl_lock_alloc(unsigned locktype);
+void _evthreadimpl_lock_free(void *lock, unsigned locktype);
+int _evthreadimpl_lock_lock(unsigned mode, void *lock);
+int _evthreadimpl_lock_unlock(unsigned mode, void *lock);
+void *_evthreadimpl_cond_alloc(unsigned condtype);
+void _evthreadimpl_cond_free(void *cond);
+int _evthreadimpl_cond_signal(void *cond, int broadcast);
+int _evthreadimpl_cond_wait(void *cond, void *lock, const struct timeval *tv);
+
+#define EVTHREAD_GET_ID() _evthreadimpl_get_id()
+#define EVBASE_IN_THREAD(base)				\
+	((base)->th_owner_id == _evthreadimpl_get_id())
+#define EVTHREAD_ALLOC_LOCK(lockvar, locktype)		\
+	((lockvar) = _evthreadimpl_lock_alloc(locktype))
+
+#define EVTHREAD_FREE_LOCK(lockvar, locktype)				\
+	do {								\
+		void *_lock_tmp_ = (lockvar);				\
+		if (_lock_tmp_)						\
+			_evthreadimpl_lock_free(_lock_tmp_, (locktype)); \
+	} while (0)
+
+/** Acquire a lock. */
+#define EVLOCK_LOCK(lockvar,mode)					\
+	do {								\
+		if (lockvar)						\
+			_evthreadimpl_lock_lock(mode, lockvar);		\
+	} while (0)
+
+/** Release a lock */
+#define EVLOCK_UNLOCK(lockvar,mode)					\
+	do {								\
+		if (lockvar)						\
+			_evthreadimpl_lock_unlock(mode, lockvar);	\
+	} while (0)
+
+/** Lock an event_base, if it is set up for locking.  Acquires the lock
+    in the base structure whose field is named 'lockvar'. */
+#define EVBASE_ACQUIRE_LOCK(base, lockvar) do {				\
+		EVLOCK_LOCK((base)->lockvar, 0);			\
+	} while (0)
+
+/** Unlock an event_base, if it is set up for locking. */
+#define EVBASE_RELEASE_LOCK(base, lockvar) do {				\
+		EVLOCK_UNLOCK((base)->lockvar, 0);			\
+	} while (0)
+
+/** If lock debugging is enabled, and lock is non-null, assert that 'lock' is
+ * locked and held by us. */
+#define EVLOCK_ASSERT_LOCKED(lock)					\
+	do {								\
+		if ((lock) && _evthreadimpl_is_lock_debugging_enabled()) { \
+			EVUTIL_ASSERT(_evthread_is_debug_lock_held(lock)); \
+		}							\
+	} while (0)
+
+/** Try to grab the lock for 'lockvar' without blocking, and return 1 if we
+ * manage to get it. */
+static inline int EVLOCK_TRY_LOCK(void *lock);
+static inline int
+EVLOCK_TRY_LOCK(void *lock)
+{
+	if (lock) {
+		int r = _evthreadimpl_lock_lock(EVTHREAD_TRY, lock);
+		return !r;
+	} else {
+		/* Locking is disabled either globally or for this thing;
+		 * of course we count as having the lock. */
+		return 1;
+	}
+}
+
+/** Allocate a new condition variable and store it in the void *, condvar */
+#define EVTHREAD_ALLOC_COND(condvar)					\
+	do {								\
+		(condvar) = _evthreadimpl_cond_alloc(0);		\
+	} while (0)
+/** Deallocate and free a condition variable in condvar */
+#define EVTHREAD_FREE_COND(cond)					\
+	do {								\
+		if (cond)						\
+			_evthreadimpl_cond_free((cond));		\
+	} while (0)
+/** Signal one thread waiting on cond */
+#define EVTHREAD_COND_SIGNAL(cond)					\
+	( (cond) ? _evthreadimpl_cond_signal((cond), 0) : 0 )
+/** Signal all threads waiting on cond */
+#define EVTHREAD_COND_BROADCAST(cond)					\
+	( (cond) ? _evthreadimpl_cond_signal((cond), 1) : 0 )
+/** Wait until the condition 'cond' is signalled.  Must be called while
+ * holding 'lock'.  The lock will be released until the condition is
+ * signalled, at which point it will be acquired again.  Returns 0 for
+ * success, -1 for failure. */
+#define EVTHREAD_COND_WAIT(cond, lock)					\
+	( (cond) ? _evthreadimpl_cond_wait((cond), (lock), NULL) : 0 )
+/** As EVTHREAD_COND_WAIT, but gives up after 'tv' has elapsed.  Returns 1
+ * on timeout. */
+#define EVTHREAD_COND_WAIT_TIMED(cond, lock, tv)			\
+	( (cond) ? _evthreadimpl_cond_wait((cond), (lock), (tv)) : 0 )
+
 #else /* _EVENT_DISABLE_THREAD_SUPPORT */
 
 #define EVTHREAD_GET_ID()	1
@@ -211,6 +296,44 @@ EVLOCK_TRY_LOCK(void *lock)
 
 #endif
 
+/* This code is shared between both lock impls */
+#if ! defined(_EVENT_DISABLE_THREAD_SUPPORT)
+/** Helper: put lockvar1 and lockvar2 into pointerwise ascending order. */
+#define _EVLOCK_SORTLOCKS(lockvar1, lockvar2)				\
+	do {								\
+		if (lockvar1 && lockvar2 && lockvar1 > lockvar2) {	\
+			void *tmp = lockvar1;				\
+			lockvar1 = lockvar2;				\
+			lockvar2 = tmp;					\
+		}							\
+	} while (0)
+
+/** Acquire both lock1 and lock2.  Always allocates locks in the same order,
+ * so that two threads locking two locks with LOCK2 will not deadlock. */
+#define EVLOCK_LOCK2(lock1,lock2,mode1,mode2)				\
+	do {								\
+		void *_lock1_tmplock = (lock1);				\
+		void *_lock2_tmplock = (lock2);				\
+		_EVLOCK_SORTLOCKS(_lock1_tmplock,_lock2_tmplock);	\
+		EVLOCK_LOCK(_lock1_tmplock,mode1);			\
+		if (_lock2_tmplock != _lock1_tmplock)			\
+			EVLOCK_LOCK(_lock2_tmplock,mode2);		\
+	} while (0)
+/** Release both lock1 and lock2.  */
+#define EVLOCK_UNLOCK2(lock1,lock2,mode1,mode2)				\
+	do {								\
+		void *_lock1_tmplock = (lock1);				\
+		void *_lock2_tmplock = (lock2);				\
+		_EVLOCK_SORTLOCKS(_lock1_tmplock,_lock2_tmplock);	\
+		if (_lock2_tmplock != _lock1_tmplock)			\
+			EVLOCK_UNLOCK(_lock2_tmplock,mode2);		\
+		EVLOCK_UNLOCK(_lock1_tmplock,mode1);			\
+	} while (0)
+
+int _evthread_is_debug_lock_held(void *lock);
+void *_evthread_debug_get_real_lock(void *lock);
+#endif
+
 #ifdef __cplusplus
 }
 #endif

evthread.c

@@ -38,13 +38,19 @@
 #include "util-internal.h"
 #include "evthread-internal.h"
 
+#ifdef EVTHREAD_EXPOSE_STRUCTS
+#define GLOBAL
+#else
+#define GLOBAL static
+#endif
+
 /* globals */
-int _evthread_lock_debugging_enabled = 0;
+GLOBAL int _evthread_lock_debugging_enabled = 0;
-struct evthread_lock_callbacks _evthread_lock_fns = {
+GLOBAL struct evthread_lock_callbacks _evthread_lock_fns = {
 	0, 0, NULL, NULL, NULL, NULL
 };
-unsigned long (*_evthread_id_fn)(void) = NULL;
+GLOBAL unsigned long (*_evthread_id_fn)(void) = NULL;
-struct evthread_condition_callbacks _evthread_cond_fns = {
+GLOBAL struct evthread_condition_callbacks _evthread_cond_fns = {
 	0, NULL, NULL, NULL, NULL
 };
 
@@ -263,4 +269,73 @@ _evthread_debug_get_real_lock(void *lock_)
 	return lock->lock;
 }
 
+#ifndef EVTHREAD_EXPOSE_STRUCTS
+unsigned long
+_evthreadimpl_get_id()
+{
+	return _evthread_id_fn ? _evthread_id_fn() : 1;
+}
+void *
+_evthreadimpl_lock_alloc(unsigned locktype)
+{
+	return _evthread_lock_fns.alloc ?
+	    _evthread_lock_fns.alloc(locktype) : NULL;
+}
+void
+_evthreadimpl_lock_free(void *lock, unsigned locktype)
+{
+	if (_evthread_lock_fns.free)
+		_evthread_lock_fns.free(lock, locktype);
+}
+int
+_evthreadimpl_lock_lock(unsigned mode, void *lock)
+{
+	if (_evthread_lock_fns.lock)
+		return _evthread_lock_fns.lock(mode, lock);
+	else
+		return 0;
+}
+int
+_evthreadimpl_lock_unlock(unsigned mode, void *lock)
+{
+	if (_evthread_lock_fns.unlock)
+		return _evthread_lock_fns.unlock(mode, lock);
+	else
+		return 0;
+}
+void *
+_evthreadimpl_cond_alloc(unsigned condtype)
+{
+	return _evthread_cond_fns.alloc_condition ?
+	    _evthread_cond_fns.alloc_condition(condtype) : NULL;
+}
+void
+_evthreadimpl_cond_free(void *cond)
+{
+	if (_evthread_cond_fns.free_condition)
+		_evthread_cond_fns.free_condition(cond);
+}
+int
+_evthreadimpl_cond_signal(void *cond, int broadcast)
+{
+	if (_evthread_cond_fns.signal_condition)
+		return _evthread_cond_fns.signal_condition(cond, broadcast);
+	else
+		return 0;
+}
+int
+_evthreadimpl_cond_wait(void *cond, void *lock, const struct timeval *tv)
+{
+	if (_evthread_cond_fns.wait_condition)
+		return _evthread_cond_fns.wait_condition(cond, lock, tv);
+	else
+		return 0;
+}
+int
+_evthreadimpl_is_lock_debugging_enabled(void)
+{
+	return _evthread_lock_debugging_enabled;
+}
+#endif
+
 #endif