[sql] Import reference version of SQLite 3.10.2.

third_party/sqlite/sqlite-src-3100200/src/btmutex.c

 /*
 ** 2007 August 27
 **
 ** The author disclaims copyright to this source code.  In place of
 ** a legal notice, here is a blessing:
 **
 **    May you do good and not evil.
 **    May you find forgiveness for yourself and forgive others.
 **    May you share freely, never taking more than you give.
 **
@@ skipping 123 matching lines @@
       lockBtreeMutex(pLater);
     }
   }
 }
 
 
 /*
 ** Exit the recursive mutex on a Btree.
 */
 void sqlite3BtreeLeave(Btree *p){
+  assert( sqlite3_mutex_held(p->db->mutex) );
   if( p->sharable ){
     assert( p->wantToLock>0 );
     p->wantToLock--;
     if( p->wantToLock==0 ){
       unlockBtreeMutex(p);
     }
   }
 }
 
 #ifndef NDEBUG
@@ skipping 137 matching lines @@
   int i;
   for(i=0; i<db->nDb; i++){
     Btree *p = db->aDb[i].pBt;
     if( p ){
       p->pBt->db = p->db;
     }
   }
 }
 #endif /* if SQLITE_THREADSAFE */
 #endif /* ifndef SQLITE_OMIT_SHARED_CACHE */