Move bundled copy of sqlite one level deeper to better separate it...

third_party/sqlite/src/mutex_unix.c

Index: third_party/sqlite/src/mutex_unix.c
===================================================================
--- third_party/sqlite/src/mutex_unix.c	(revision 56608)
+++ third_party/sqlite/src/mutex_unix.c	(working copy)
@@ -1,329 +0,0 @@
-/*
-** 2007 August 28
-**
-** 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.
-**
-*************************************************************************
-** This file contains the C functions that implement mutexes for pthreads
-**
-** $Id: mutex_unix.c,v 1.16 2008/12/08 18:19:18 drh Exp $
-*/
-#include "sqliteInt.h"
-
-/*
-** The code in this file is only used if we are compiling threadsafe
-** under unix with pthreads.
-**
-** Note that this implementation requires a version of pthreads that
-** supports recursive mutexes.
-*/
-#ifdef SQLITE_MUTEX_PTHREADS
-
-#include <pthread.h>
-
-
-/*
-** Each recursive mutex is an instance of the following structure.
-*/
-struct sqlite3_mutex {
-  pthread_mutex_t mutex;     /* Mutex controlling the lock */
-  int id;                    /* Mutex type */
-  int nRef;                  /* Number of entrances */
-  pthread_t owner;           /* Thread that is within this mutex */
-#ifdef SQLITE_DEBUG
-  int trace;                 /* True to trace changes */
-#endif
-};
-#ifdef SQLITE_DEBUG
-#define SQLITE3_MUTEX_INITIALIZER { PTHREAD_MUTEX_INITIALIZER, 0, 0, (pthread_t)0, 0 }
-#else
-#define SQLITE3_MUTEX_INITIALIZER { PTHREAD_MUTEX_INITIALIZER, 0, 0, (pthread_t)0 }
-#endif
-
-/*
-** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routine are
-** intended for use only inside assert() statements.  On some platforms,
-** there might be race conditions that can cause these routines to
-** deliver incorrect results.  In particular, if pthread_equal() is
-** not an atomic operation, then these routines might delivery
-** incorrect results.  On most platforms, pthread_equal() is a 
-** comparison of two integers and is therefore atomic.  But we are
-** told that HPUX is not such a platform.  If so, then these routines
-** will not always work correctly on HPUX.
-**
-** On those platforms where pthread_equal() is not atomic, SQLite
-** should be compiled without -DSQLITE_DEBUG and with -DNDEBUG to
-** make sure no assert() statements are evaluated and hence these
-** routines are never called.
-*/
-#if !defined(NDEBUG) || defined(SQLITE_DEBUG)
-static int pthreadMutexHeld(sqlite3_mutex *p){
-  return (p->nRef!=0 && pthread_equal(p->owner, pthread_self()));
-}
-static int pthreadMutexNotheld(sqlite3_mutex *p){
-  return p->nRef==0 || pthread_equal(p->owner, pthread_self())==0;
-}
-#endif
-
-/*
-** Initialize and deinitialize the mutex subsystem.
-*/
-static int pthreadMutexInit(void){ return SQLITE_OK; }
-static int pthreadMutexEnd(void){ return SQLITE_OK; }
-
-/*
-** The sqlite3_mutex_alloc() routine allocates a new
-** mutex and returns a pointer to it.  If it returns NULL
-** that means that a mutex could not be allocated.  SQLite
-** will unwind its stack and return an error.  The argument
-** to sqlite3_mutex_alloc() is one of these integer constants:
-**
-** <ul>
-** <li>  SQLITE_MUTEX_FAST
-** <li>  SQLITE_MUTEX_RECURSIVE
-** <li>  SQLITE_MUTEX_STATIC_MASTER
-** <li>  SQLITE_MUTEX_STATIC_MEM
-** <li>  SQLITE_MUTEX_STATIC_MEM2
-** <li>  SQLITE_MUTEX_STATIC_PRNG
-** <li>  SQLITE_MUTEX_STATIC_LRU
-** <li>  SQLITE_MUTEX_STATIC_LRU2
-** </ul>
-**
-** The first two constants cause sqlite3_mutex_alloc() to create
-** a new mutex.  The new mutex is recursive when SQLITE_MUTEX_RECURSIVE
-** is used but not necessarily so when SQLITE_MUTEX_FAST is used.
-** The mutex implementation does not need to make a distinction
-** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does
-** not want to.  But SQLite will only request a recursive mutex in
-** cases where it really needs one.  If a faster non-recursive mutex
-** implementation is available on the host platform, the mutex subsystem
-** might return such a mutex in response to SQLITE_MUTEX_FAST.
-**
-** The other allowed parameters to sqlite3_mutex_alloc() each return
-** a pointer to a static preexisting mutex.  Six static mutexes are
-** used by the current version of SQLite.  Future versions of SQLite
-** may add additional static mutexes.  Static mutexes are for internal
-** use by SQLite only.  Applications that use SQLite mutexes should
-** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or
-** SQLITE_MUTEX_RECURSIVE.
-**
-** Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST
-** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc()
-** returns a different mutex on every call.  But for the static 
-** mutex types, the same mutex is returned on every call that has
-** the same type number.
-*/
-static sqlite3_mutex *pthreadMutexAlloc(int iType){
-  static sqlite3_mutex staticMutexes[] = {
-    SQLITE3_MUTEX_INITIALIZER,
-    SQLITE3_MUTEX_INITIALIZER,
-    SQLITE3_MUTEX_INITIALIZER,
-    SQLITE3_MUTEX_INITIALIZER,
-    SQLITE3_MUTEX_INITIALIZER,
-    SQLITE3_MUTEX_INITIALIZER
-  };
-  sqlite3_mutex *p;
-  switch( iType ){
-    case SQLITE_MUTEX_RECURSIVE: {
-      p = sqlite3MallocZero( sizeof(*p) );
-      if( p ){
-#ifdef SQLITE_HOMEGROWN_RECURSIVE_MUTEX
-        /* If recursive mutexes are not available, we will have to
-        ** build our own.  See below. */
-        pthread_mutex_init(&p->mutex, 0);
-#else
-        /* Use a recursive mutex if it is available */
-        pthread_mutexattr_t recursiveAttr;
-        pthread_mutexattr_init(&recursiveAttr);
-        pthread_mutexattr_settype(&recursiveAttr, PTHREAD_MUTEX_RECURSIVE);
-        pthread_mutex_init(&p->mutex, &recursiveAttr);
-        pthread_mutexattr_destroy(&recursiveAttr);
-#endif
-        p->id = iType;
-      }
-      break;
-    }
-    case SQLITE_MUTEX_FAST: {
-      p = sqlite3MallocZero( sizeof(*p) );
-      if( p ){
-        p->id = iType;
-        pthread_mutex_init(&p->mutex, 0);
-      }
-      break;
-    }
-    default: {
-      assert( iType-2 >= 0 );
-      assert( iType-2 < ArraySize(staticMutexes) );
-      p = &staticMutexes[iType-2];
-      p->id = iType;
-      break;
-    }
-  }
-  return p;
-}
-
-
-/*
-** This routine deallocates a previously
-** allocated mutex.  SQLite is careful to deallocate every
-** mutex that it allocates.
-*/
-static void pthreadMutexFree(sqlite3_mutex *p){
-  assert( p->nRef==0 );
-  assert( p->id==SQLITE_MUTEX_FAST || p->id==SQLITE_MUTEX_RECURSIVE );
-  pthread_mutex_destroy(&p->mutex);
-  sqlite3_free(p);
-}
-
-/*
-** The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt
-** to enter a mutex.  If another thread is already within the mutex,
-** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return
-** SQLITE_BUSY.  The sqlite3_mutex_try() interface returns SQLITE_OK
-** upon successful entry.  Mutexes created using SQLITE_MUTEX_RECURSIVE can
-** be entered multiple times by the same thread.  In such cases the,
-** mutex must be exited an equal number of times before another thread
-** can enter.  If the same thread tries to enter any other kind of mutex
-** more than once, the behavior is undefined.
-*/
-static void pthreadMutexEnter(sqlite3_mutex *p){
-  assert( p->id==SQLITE_MUTEX_RECURSIVE || pthreadMutexNotheld(p) );
-
-#ifdef SQLITE_HOMEGROWN_RECURSIVE_MUTEX
-  /* If recursive mutexes are not available, then we have to grow
-  ** our own.  This implementation assumes that pthread_equal()
-  ** is atomic - that it cannot be deceived into thinking self
-  ** and p->owner are equal if p->owner changes between two values
-  ** that are not equal to self while the comparison is taking place.
-  ** This implementation also assumes a coherent cache - that 
-  ** separate processes cannot read different values from the same
-  ** address at the same time.  If either of these two conditions
-  ** are not met, then the mutexes will fail and problems will result.
-  */
-  {
-    pthread_t self = pthread_self();
-    if( p->nRef>0 && pthread_equal(p->owner, self) ){
-      p->nRef++;
-    }else{
-      pthread_mutex_lock(&p->mutex);
-      assert( p->nRef==0 );
-      p->owner = self;
-      p->nRef = 1;
-    }
-  }
-#else
-  /* Use the built-in recursive mutexes if they are available.
-  */
-  pthread_mutex_lock(&p->mutex);
-  p->owner = pthread_self();
-  p->nRef++;
-#endif
-
-#ifdef SQLITE_DEBUG
-  if( p->trace ){
-    printf("enter mutex %p (%d) with nRef=%d\n", p, p->trace, p->nRef);
-  }
-#endif
-}
-static int pthreadMutexTry(sqlite3_mutex *p){
-  int rc;
-  assert( p->id==SQLITE_MUTEX_RECURSIVE || pthreadMutexNotheld(p) );
-
-#ifdef SQLITE_HOMEGROWN_RECURSIVE_MUTEX
-  /* If recursive mutexes are not available, then we have to grow
-  ** our own.  This implementation assumes that pthread_equal()
-  ** is atomic - that it cannot be deceived into thinking self
-  ** and p->owner are equal if p->owner changes between two values
-  ** that are not equal to self while the comparison is taking place.
-  ** This implementation also assumes a coherent cache - that 
-  ** separate processes cannot read different values from the same
-  ** address at the same time.  If either of these two conditions
-  ** are not met, then the mutexes will fail and problems will result.
-  */
-  {
-    pthread_t self = pthread_self();
-    if( p->nRef>0 && pthread_equal(p->owner, self) ){
-      p->nRef++;
-      rc = SQLITE_OK;
-    }else if( pthread_mutex_trylock(&p->mutex)==0 ){
-      assert( p->nRef==0 );
-      p->owner = self;
-      p->nRef = 1;
-      rc = SQLITE_OK;
-    }else{
-      rc = SQLITE_BUSY;
-    }
-  }
-#else
-  /* Use the built-in recursive mutexes if they are available.
-  */
-  if( pthread_mutex_trylock(&p->mutex)==0 ){
-    p->owner = pthread_self();
-    p->nRef++;
-    rc = SQLITE_OK;
-  }else{
-    rc = SQLITE_BUSY;
-  }
-#endif
-
-#ifdef SQLITE_DEBUG
-  if( rc==SQLITE_OK && p->trace ){
-    printf("enter mutex %p (%d) with nRef=%d\n", p, p->trace, p->nRef);
-  }
-#endif
-  return rc;
-}
-
-/*
-** The sqlite3_mutex_leave() routine exits a mutex that was
-** previously entered by the same thread.  The behavior
-** is undefined if the mutex is not currently entered or
-** is not currently allocated.  SQLite will never do either.
-*/
-static void pthreadMutexLeave(sqlite3_mutex *p){
-  assert( pthreadMutexHeld(p) );
-  p->nRef--;
-  assert( p->nRef==0 || p->id==SQLITE_MUTEX_RECURSIVE );
-
-#ifdef SQLITE_HOMEGROWN_RECURSIVE_MUTEX
-  if( p->nRef==0 ){
-    pthread_mutex_unlock(&p->mutex);
-  }
-#else
-  pthread_mutex_unlock(&p->mutex);
-#endif
-
-#ifdef SQLITE_DEBUG
-  if( p->trace ){
-    printf("leave mutex %p (%d) with nRef=%d\n", p, p->trace, p->nRef);
-  }
-#endif
-}
-
-sqlite3_mutex_methods *sqlite3DefaultMutex(void){
-  static sqlite3_mutex_methods sMutex = {
-    pthreadMutexInit,
-    pthreadMutexEnd,
-    pthreadMutexAlloc,
-    pthreadMutexFree,
-    pthreadMutexEnter,
-    pthreadMutexTry,
-    pthreadMutexLeave,
-#ifdef SQLITE_DEBUG
-    pthreadMutexHeld,
-    pthreadMutexNotheld
-#else
-    0,
-    0
-#endif
-  };
-
-  return &sMutex;
-}
-
-#endif /* SQLITE_MUTEX_PTHREAD */