SQLite

  testcase( w.eCode==0 );
  testcase( w.eCode==CKCNSTRNT_COLUMN );
  testcase( w.eCode==CKCNSTRNT_ROWID );
  testcase( w.eCode==(CKCNSTRNT_ROWID|CKCNSTRNT_COLUMN) );
  return !w.eCode;
}

/*
** An instance of the ConstraintAddr object remembers the byte-code addresses
** for sections of the constraint checks that deal with uniqueness constraints
** on the rowid and on the upsert constraint.
**
** This information is passed into checkReorderConstraintChecks() to insert
** some OP_Goto operations so that the rowid and upsert constraints occur
** in the correct order relative to other constraints.
*/
typedef struct ConstraintAddr ConstraintAddr;
struct ConstraintAddr {
  int ipkTop;          /* Subroutine for rowid constraint check */
  int upsertTop;       /* Label for upsert constraint check subroutine */
  int upsertTop2;      /* Copy of upsertTop not cleared by the call */
  int upsertBtm;       /* upsert constraint returns to this label */
  int ipkBtm;          /* Return opcode rowid constraint check */
};

/*
** Generate any OP_Goto operations needed to cause constraints to be
** run that haven't already been run.
*/
static void reorderConstraintChecks(Vdbe *v, ConstraintAddr *p){
  if( p->upsertTop ){
    testcase( sqlite3VdbeLabelHasBeenResolved(v, p->upsertTop) );
    sqlite3VdbeGoto(v, p->upsertTop);
    VdbeComment((v, "call upsert subroutine"));
    sqlite3VdbeResolveLabel(v, p->upsertBtm);
    p->upsertTop = 0;
  }
  if( p->ipkTop ){
    sqlite3VdbeGoto(v, p->ipkTop);
    VdbeComment((v, "call rowid unique-check subroutine"));
    sqlite3VdbeJumpHere(v, p->ipkBtm);
    p->ipkTop = 0;
  }
}

/*
** Generate code to do constraint checks prior to an INSERT or an UPDATE
** on table pTab.
**
** The regNewData parameter is the first register in a range that contains
** the data to be inserted or the data after the update.  There will be
** pTab->nCol+1 registers in this range.  The first register (the one

  int i;               /* loop counter */
  int ix;              /* Index loop counter */
  int nCol;            /* Number of columns */
  int onError;         /* Conflict resolution strategy */
  int addr1;           /* Address of jump instruction */
  int seenReplace = 0; /* True if REPLACE is used to resolve INT PK conflict */
  int nPkField;        /* Number of fields in PRIMARY KEY. 1 for ROWID tables */
  ConstraintAddr sAddr;/* Address information for constraint reordering */
  Index *pUpIdx = 0;   /* Index to which to apply the upsert */
  u8 isUpdate;         /* True if this is an UPDATE operation */
  u8 bAffinityDone = 0;  /* True if the OP_Affinity operation has been run */
  int upsertBypass = 0;  /* Address of Goto to bypass upsert subroutine */
  int upsertJump = 0;    /* Address of Goto that jumps into upsert subroutine */
  int ipkTop = 0;        /* Top of the IPK uniqueness check */
  int ipkBottom = 0;     /* OP_Goto at the end of the IPK uniqueness check */

  isUpdate = regOldData!=0;
  db = pParse->db;
  v = sqlite3GetVdbe(pParse);
  assert( v!=0 );
  assert( pTab->pSelect==0 );  /* This table is not a VIEW */
  nCol = pTab->nCol;
  memset(&sAddr, 0, sizeof(sAddr));
  
  /* pPk is the PRIMARY KEY index for WITHOUT ROWID tables and NULL for
  ** normal rowid tables.  nPkField is the number of key fields in the 
  ** pPk index or 1 for a rowid table.  In other words, nPkField is the
  ** number of fields in the true primary key of the table. */
  if( HasRowid(pTab) ){
    pPk = 0;

    pParse->iSelfTab = 0;
  }
#endif /* !defined(SQLITE_OMIT_CHECK) */

  /* UNIQUE and PRIMARY KEY constraints should be handled in the following
  ** order:
  **
  **   (1)  OE_Abort, OE_Fail, OE_Rollback, OE_Ignore
  **   (2)  OE_Update
  **   (1)  OE_Update
  **   (2)  OE_Abort, OE_Fail, OE_Rollback, OE_Ignore
  **   (3)  OE_Replace
  **
  ** OE_Fail and OE_Ignore must happen before any changes are made.
  ** OE_Update guarantees that only a single row will change, so it
  ** must happen before OE_Replace.  Technically, OE_Abort and OE_Rollback
  ** could happen in any order, but they are grouped up front for
  ** convenience.
  **
  ** 2018-08-14: Ticket https://www.sqlite.org/src/info/908f001483982c43
  ** The order of constraints used to have OE_Update as (2) and OE_Abort
  ** and so forth as (1). But apparently PostgreSQL checks the OE_Update
  ** constraint before any others, so it had to be moved.
  **
  ** Constraint checking code is generated in this order:
  **   (A)  The rowid constraint
  **   (B)  Unique index constraints that do not have OE_Replace as their
  **        default conflict resolution strategy
  **   (C)  Unique index that do use OE_Replace by default.
  **
  ** The ordering of (2) and (3) is accomplished by making sure the linked
  ** list of indexes attached to a table puts all OE_Replace indexes last
  ** in the list.  See sqlite3CreateIndex() for where that happens.
  */

  if( pUpsert ){
    if( pUpsert->pUpsertTarget==0 ){
      /* An ON CONFLICT DO NOTHING clause, without a constraint-target.
      ** Make all unique constraint resolution be OE_Ignore */
      assert( pUpsert->pUpsertSet==0 );
      overrideError = OE_Ignore;
      pUpsert = 0;
    }else if( (pUpIdx = pUpsert->pUpsertIdx)!=0 ){
      /* If the constraint-target is on some column other than
      /* If the constraint-target uniqueness check must be run first.
      ** then ROWID, then we might need to move the UPSERT around
      ** so that it occurs in the correct order. */
      ** Jump to that uniqueness check now */
      sAddr.upsertTop = sAddr.upsertTop2 = sqlite3VdbeMakeLabel(v);
      sAddr.upsertBtm = sqlite3VdbeMakeLabel(v);
      upsertJump = sqlite3VdbeAddOp0(v, OP_Goto);
      VdbeComment((v, "UPSERT constraint goes first"));
    }
  }

  /* If rowid is changing, make sure the new rowid does not previously
  ** exist in the table.
  */
  if( pkChng && pPk==0 ){

    }

    /* If the response to a rowid conflict is REPLACE but the response
    ** to some other UNIQUE constraint is FAIL or IGNORE, then we need
    ** to defer the running of the rowid conflict checking until after
    ** the UNIQUE constraints have run.
    */
    assert( OE_Update>OE_Replace );
    assert( OE_Ignore<OE_Replace );
    assert( OE_Fail<OE_Replace );
    assert( OE_Abort<OE_Replace );
    assert( OE_Rollback<OE_Replace );
    if( onError>=OE_Replace
     && (pUpsert || onError!=overrideError)
     && pTab->pIndex
    if( onError==OE_Replace      /* IPK rule is REPLACE */
     && onError!=overrideError   /* Rules for other contraints are different */
     && pTab->pIndex             /* There exist other constraints */
    ){
      sAddr.ipkTop = sqlite3VdbeAddOp0(v, OP_Goto)+1;
      ipkTop = sqlite3VdbeAddOp0(v, OP_Goto)+1;
      VdbeComment((v, "defer IPK REPLACE until last"));
    }

    if( isUpdate ){
      /* pkChng!=0 does not mean that the rowid has changed, only that
      ** it might have changed.  Skip the conflict logic below if the rowid
      ** is unchanged. */
      sqlite3VdbeAddOp3(v, OP_Eq, regNewData, addrRowidOk, regOldData);

      case OE_Ignore: {
        testcase( onError==OE_Ignore );
        sqlite3VdbeGoto(v, ignoreDest);
        break;
      }
    }
    sqlite3VdbeResolveLabel(v, addrRowidOk);
    if( sAddr.ipkTop ){
      sAddr.ipkBtm = sqlite3VdbeAddOp0(v, OP_Goto);
      sqlite3VdbeJumpHere(v, sAddr.ipkTop-1);
    if( ipkTop ){
      ipkBottom = sqlite3VdbeAddOp0(v, OP_Goto);
      sqlite3VdbeJumpHere(v, ipkTop-1);
    }
  }

  /* Test all UNIQUE constraints by creating entries for each UNIQUE
  ** index and making sure that duplicate entries do not already exist.
  ** Compute the revised record entries for indices as we go.
  **
  ** This loop also handles the case of the PRIMARY KEY index for a
  ** WITHOUT ROWID table.
  */
  for(ix=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, ix++){
    int regIdx;          /* Range of registers hold conent for pIdx */
    int regR;            /* Range of registers holding conflicting PK */
    int iThisCur;        /* Cursor for this UNIQUE index */
    int addrUniqueOk;    /* Jump here if the UNIQUE constraint is satisfied */

    if( aRegIdx[ix]==0 ) continue;  /* Skip indices that do not change */
    if( bAffinityDone==0 ){
      sqlite3TableAffinity(v, pTab, regNewData+1);
      bAffinityDone = 1;
    }
    if( pUpIdx==pIdx ){
      addrUniqueOk = sAddr.upsertBtm;
      addrUniqueOk = upsertJump+1;
      upsertBypass = sqlite3VdbeGoto(v, 0);
      VdbeComment((v, "Skip upsert subroutine"));
      sqlite3VdbeResolveLabel(v, sAddr.upsertTop2);
      sqlite3VdbeJumpHere(v, upsertJump);
    }else{
      addrUniqueOk = sqlite3VdbeMakeLabel(v);
    }
    if( bAffinityDone==0 && (pUpIdx==0 || pUpIdx==pIdx) ){
      sqlite3TableAffinity(v, pTab, regNewData+1);
      bAffinityDone = 1;
    }
    VdbeNoopComment((v, "uniqueness check for %s", pIdx->zName));
    iThisCur = iIdxCur+ix;


    /* Skip partial indices for which the WHERE clause is not true */
    if( pIdx->pPartIdxWhere ){

      if( pUpsert->pUpsertSet==0 ){
        onError = OE_Ignore;  /* DO NOTHING is the same as INSERT OR IGNORE */
      }else{
        onError = OE_Update;  /* DO UPDATE */
      }
    }

    /* Invoke subroutines to handle IPK replace and upsert prior to running
    ** the first REPLACE constraint check. */
    if( onError==OE_Replace ){
      testcase( sAddr.ipkTop );
      testcase( sAddr.upsertTop
             && sqlite3VdbeLabelHasBeenResolved(v,sAddr.upsertTop) );
      reorderConstraintChecks(v, &sAddr);
    }

    /* Collision detection may be omitted if all of the following are true:
    **   (1) The conflict resolution algorithm is REPLACE
    **   (2) The table is a WITHOUT ROWID table
    **   (3) There are no secondary indexes on the table
    **   (4) No delete triggers need to be fired if there is a conflict
    **   (5) No FK constraint counters need to be updated if a conflict occurs.
    */ 

            regR, nPkField, 0, OE_Replace,
            (pIdx==pPk ? ONEPASS_SINGLE : ONEPASS_OFF), iThisCur);
        seenReplace = 1;
        break;
      }
    }
    if( pUpIdx==pIdx ){
      sqlite3VdbeGoto(v, upsertJump+1);
      sqlite3VdbeJumpHere(v, upsertBypass);
    }else{
      sqlite3VdbeResolveLabel(v, addrUniqueOk);
    }
    if( regR!=regIdx ) sqlite3ReleaseTempRange(pParse, regR, nPkField);

  }
  testcase( sAddr.ipkTop!=0 );
  }

  /* If the IPK constraint is a REPLACE, run it last */
  if( ipkTop ){
  testcase( sAddr.upsertTop
         && sqlite3VdbeLabelHasBeenResolved(v,sAddr.upsertTop) );
  reorderConstraintChecks(v, &sAddr);
  
    sqlite3VdbeGoto(v, ipkTop+1);
    VdbeComment((v, "Do IPK REPLACE"));
    sqlite3VdbeJumpHere(v, ipkBottom);
  }

  *pbMayReplace = seenReplace;
  VdbeModuleComment((v, "END: GenCnstCks(%d)", seenReplace));
}

#ifdef SQLITE_ENABLE_NULL_TRIM
/*
** Change the P5 operand on the last opcode (which should be an OP_MakeRecord)

** Function unixMutexHeld() is used to assert() that the global mutex 
** is held when required. This function is only used as part of assert() 
** statements. e.g.
**
**   unixEnterMutex()
**     assert( unixMutexHeld() );
**   unixEnterLeave()
**
** To prevent deadlock, the global unixBigLock must must be acquired
** before the unixInodeInfo.pLockMutex mutex, if both are held.  It is
** OK to get the pLockMutex without holding unixBigLock first, but if
** that happens, the unixBigLock mutex must not be acquired until after
** pLockMutex is released.
**
**      OK:     enter(unixBigLock),  enter(pLockInfo)
**      OK:     enter(unixBigLock)
**      OK:     enter(pLockInfo)
**   ERROR:     enter(pLockInfo), enter(unixBigLock)
*/
static sqlite3_mutex *unixBigLock = 0;
static void unixEnterMutex(void){
  assert( sqlite3_mutex_notheld(unixBigLock) );  /* Not a recursive mutex */
  sqlite3_mutex_enter(unixBigLock);
}
static void unixLeaveMutex(void){
  assert( sqlite3_mutex_held(unixBigLock) );
  sqlite3_mutex_leave(unixBigLock);
}
#ifdef SQLITE_DEBUG
static int unixMutexHeld(void) {
  return sqlite3_mutex_held(unixBigLock);
}
#endif

**
** A single inode can have multiple file descriptors, so each unixFile
** structure contains a pointer to an instance of this object and this
** object keeps a count of the number of unixFile pointing to it.
**
** Mutex rules:
**
**  (1) The pLockMutex mutex must be held in order to read or write
**  (1) Only the pLockMutex mutex must be held in order to read or write
**      any of the locking fields:
**          nShared, nLock, eFileLock, or bProcessLock
**          nShared, nLock, eFileLock, bProcessLock, pUnused
**
**  (2) When nRef>0, then the following fields are unchanging and can
**      be read (but not written) without holding any mutex:
**          fileId, pLockMutex
**
**  (3) With the exceptions above, all the fields may only be read
**      or written while holding the global unixBigLock mutex.
**
** Deadlock prevention:  The global unixBigLock mutex may not
** be acquired while holding the pLockMutex mutex.  If both unixBigLock
** and pLockMutex are needed, then unixBigLock must be acquired first.
*/
struct unixInodeInfo {
  struct unixFileId fileId;       /* The lookup key */
  sqlite3_mutex *pLockMutex;      /* Hold this mutex for... */
  int nShared;                      /* Number of SHARED locks held */
  int nLock;                        /* Number of outstanding file locks */
  unsigned char eFileLock;          /* One of SHARED_LOCK, RESERVED_LOCK etc. */
  unsigned char bProcessLock;       /* An exclusive process lock is held */
  UnixUnusedFd *pUnused;            /* Unused file descriptors to close */
  int nRef;                       /* Number of pointers to this structure */
  unixShmNode *pShmNode;          /* Shared memory associated with this inode */
  UnixUnusedFd *pUnused;          /* Unused file descriptors to close */
  unixInodeInfo *pNext;           /* List of all unixInodeInfo objects */
  unixInodeInfo *pPrev;           /*    .... doubly linked */
#if SQLITE_ENABLE_LOCKING_STYLE
  unsigned long long sharedByte;  /* for AFP simulated shared lock */
#endif
#if OS_VXWORKS
  sem_t *pSem;                    /* Named POSIX semaphore */
  char aSemName[MAX_PATHNAME+2];  /* Name of that semaphore */
#endif
};

/*
** A lists of all unixInodeInfo objects.
*/
static unixInodeInfo *inodeList = 0;  /* All unixInodeInfo objects */
static unsigned int nUnusedFd = 0;    /* Total unused file descriptors */

#ifdef SQLITE_DEBUG
/*
** True if the inode mutex is held, or not.  Used only within assert()
** to help verify correct mutex usage.
*/
int unixFileMutexHeld(unixFile *pFile){
  assert( pFile->pInode );
  return sqlite3_mutex_held(pFile->pInode->pLockMutex);
}
int unixFileMutexNotheld(unixFile *pFile){
  assert( pFile->pInode );
  return sqlite3_mutex_notheld(pFile->pInode->pLockMutex);
}
#endif

/*
**
** This function - unixLogErrorAtLine(), is only ever called via the macro
** unixLogError().
**
** It is invoked after an error occurs in an OS function and errno has been

/*
** Close all file descriptors accumuated in the unixInodeInfo->pUnused list.
*/ 
static void closePendingFds(unixFile *pFile){
  unixInodeInfo *pInode = pFile->pInode;
  UnixUnusedFd *p;
  UnixUnusedFd *pNext;
  assert( unixFileMutexHeld(pFile) );
  for(p=pInode->pUnused; p; p=pNext){
    pNext = p->pNext;
    robust_close(pFile, p->fd, __LINE__);
    sqlite3_free(p);
    nUnusedFd--;
  }
  pInode->pUnused = 0;
}

/*
** Release a unixInodeInfo structure previously allocated by findInodeInfo().
**
** The mutex entered using the unixEnterMutex() function must be held
** when this function is called.
*/
static void releaseInodeInfo(unixFile *pFile){
  unixInodeInfo *pInode = pFile->pInode;
  assert( unixMutexHeld() );
  assert( unixFileMutexNotheld(pFile) );
  if( ALWAYS(pInode) ){
    pInode->nRef--;
    if( pInode->nRef==0 ){
      assert( pInode->pShmNode==0 );
      sqlite3_mutex_enter(pInode->pLockMutex);
      closePendingFds(pFile);
      sqlite3_mutex_leave(pInode->pLockMutex);
      if( pInode->pPrev ){
        assert( pInode->pPrev->pNext==pInode );
        pInode->pPrev->pNext = pInode->pNext;
      }else{
        assert( inodeList==pInode );
        inodeList = pInode->pNext;
      }
      if( pInode->pNext ){
        assert( pInode->pNext->pPrev==pInode );
        pInode->pNext->pPrev = pInode->pPrev;
      }
      sqlite3_mutex_free(pInode->pLockMutex);
      sqlite3_free(pInode);
    }
  }
  assert( inodeList!=0 || nUnusedFd==0 );
}

/*
** Given a file descriptor, locate the unixInodeInfo object that
** describes that file descriptor.  Create a new one if necessary.  The
** return value might be uninitialized if an error occurs.
**

  memset(&fileId, 0, sizeof(fileId));
  fileId.dev = statbuf.st_dev;
#if OS_VXWORKS
  fileId.pId = pFile->pId;
#else
  fileId.ino = (u64)statbuf.st_ino;
#endif
  assert( inodeList!=0 || nUnusedFd==0 );
  pInode = inodeList;
  while( pInode && memcmp(&fileId, &pInode->fileId, sizeof(fileId)) ){
    pInode = pInode->pNext;
  }
  if( pInode==0 ){
    pInode = sqlite3_malloc64( sizeof(*pInode) );
    if( pInode==0 ){

/*
** Add the file descriptor used by file handle pFile to the corresponding
** pUnused list.
*/
static void setPendingFd(unixFile *pFile){
  unixInodeInfo *pInode = pFile->pInode;
  UnixUnusedFd *p = pFile->pPreallocatedUnused;
  assert( unixFileMutexHeld(pFile) );
  p->pNext = pInode->pUnused;
  pInode->pUnused = p;
  pFile->h = -1;
  pFile->pPreallocatedUnused = 0;
  nUnusedFd++;
}

/*
** Lower the locking level on file descriptor pFile to eFileLock.  eFileLock
** must be either NO_LOCK or SHARED_LOCK.
**
** If the locking level of the file descriptor is already at or below

    /* Decrement the count of locks against this same file.  When the
    ** count reaches zero, close any other file descriptors whose close
    ** was deferred because of outstanding locks.
    */
    pInode->nLock--;
    assert( pInode->nLock>=0 );
    if( pInode->nLock==0 ){
    if( pInode->nLock==0 ) closePendingFds(pFile);
      closePendingFds(pFile);
    }
  }

end_unlock:
  sqlite3_mutex_leave(pInode->pLockMutex);
  if( rc==SQLITE_OK ) pFile->eFileLock = eFileLock;
  if( rc==SQLITE_OK ){
    pFile->eFileLock = eFileLock;
  }
  return rc;
}

/*
** Lower the locking level on file descriptor pFile to eFileLock.  eFileLock
** must be either NO_LOCK or SHARED_LOCK.
**

/*
** Close a file.
*/
static int unixClose(sqlite3_file *id){
  int rc = SQLITE_OK;
  unixFile *pFile = (unixFile *)id;
  unixInodeInfo *pInode = pFile->pInode;

  assert( pInode!=0 );
  verifyDbFile(pFile);
  unixUnlock(id, NO_LOCK);
  assert( unixFileMutexNotheld(pFile) );
  unixEnterMutex();

  /* unixFile.pInode is always valid here. Otherwise, a different close
  ** routine (e.g. nolockClose()) would be called instead.
  */
  assert( pFile->pInode->nLock>0 || pFile->pInode->bProcessLock==0 );
  sqlite3_mutex_enter(pInode->pLockMutex);
  if( ALWAYS(pFile->pInode) && pFile->pInode->nLock ){
  if( pFile->pInode->nLock ){
    /* If there are outstanding locks, do not actually close the file just
    ** yet because that would clear those locks.  Instead, add the file
    ** descriptor to pInode->pUnused list.  It will be automatically closed 
    ** when the last lock is cleared.
    */
    setPendingFd(pFile);
  }
  sqlite3_mutex_leave(pInode->pLockMutex);
  releaseInodeInfo(pFile);
  rc = closeUnixFile(id);
  unixLeaveMutex();
  return rc;
}

/************** End of the posix advisory lock implementation *****************

 ** Close a file.
 */
static int semXClose(sqlite3_file *id) {
  if( id ){
    unixFile *pFile = (unixFile*)id;
    semXUnlock(id, NO_LOCK);
    assert( pFile );
    assert( unixFileMutexNotheld(pFile) );
    unixEnterMutex();
    releaseInodeInfo(pFile);
    unixLeaveMutex();
    closeUnixFile(id);
  }
  return SQLITE_OK;
}

        pInode->eFileLock = NO_LOCK;
        pFile->eFileLock = NO_LOCK;
      }
    }
    if( rc==SQLITE_OK ){
      pInode->nLock--;
      assert( pInode->nLock>=0 );
      if( pInode->nLock==0 ){
      if( pInode->nLock==0 ) closePendingFds(pFile);
        closePendingFds(pFile);
      }
    }
  }
  
  sqlite3_mutex_leave(pInode->pLockMutex);
  if( rc==SQLITE_OK ) pFile->eFileLock = eFileLock;
  if( rc==SQLITE_OK ){
    pFile->eFileLock = eFileLock;
  }
  return rc;
}

/*
** Close a file & cleanup AFP specific locking context 
*/
static int afpClose(sqlite3_file *id) {
  int rc = SQLITE_OK;
  unixFile *pFile = (unixFile*)id;
  assert( id!=0 );
  afpUnlock(id, NO_LOCK);
  assert( unixFileMutexNotheld(pFile) );
  unixEnterMutex();
  if( pFile->pInode && pFile->pInode->nLock ){
    /* If there are outstanding locks, do not actually close the file just
    ** yet because that would clear those locks.  Instead, add the file
    ** descriptor to pInode->aPending.  It will be automatically closed when
    ** the last lock is cleared.
    */
    setPendingFd(pFile);
  if( pFile->pInode ){
    unixInodeInfo *pInode = pFile->pInode;
    sqlite3_mutex_enter(pInode->pLockMutex);
    if( pFile->pInode->nLock ){
      /* If there are outstanding locks, do not actually close the file just
      ** yet because that would clear those locks.  Instead, add the file
      ** descriptor to pInode->aPending.  It will be automatically closed when
      ** the last lock is cleared.
      */
      setPendingFd(pFile);
    }
    sqlite3_mutex_leave(pInode->pLockMutex);
  }
  releaseInodeInfo(pFile);
  sqlite3_free(pFile->lockingContext);
  rc = closeUnixFile(id);
  unixLeaveMutex();
  return rc;
}

  if( p==0 ) return SQLITE_NOMEM_BKPT;
  memset(p, 0, sizeof(*p));
  assert( pDbFd->pShm==0 );

  /* Check to see if a unixShmNode object already exists. Reuse an existing
  ** one if present. Create a new one if necessary.
  */
  assert( unixFileMutexNotheld(pDbFd) );
  unixEnterMutex();
  pInode = pDbFd->pInode;
  pShmNode = pInode->pShmNode;
  if( pShmNode==0 ){
    struct stat sStat;                 /* fstat() info for database file */
#ifndef SQLITE_SHM_DIRECTORY
    const char *zBasePath = pDbFd->zPath;

** any load or store begun after the barrier.
*/
static void unixShmBarrier(
  sqlite3_file *fd                /* Database file holding the shared memory */
){
  UNUSED_PARAMETER(fd);
  sqlite3MemoryBarrier();         /* compiler-defined memory barrier */
  assert( unixFileMutexNotheld((unixFile*)fd) );
  unixEnterMutex();               /* Also mutex, for redundancy */
  unixLeaveMutex();
}

/*
** Close a connection to shared-memory.  Delete the underlying 
** storage if deleteFlag is true.

  /* Free the connection p */
  sqlite3_free(p);
  pDbFd->pShm = 0;
  sqlite3_mutex_leave(pShmNode->mutex);

  /* If pShmNode->nRef has reached 0, then close the underlying
  ** shared-memory file, too */
  assert( unixFileMutexNotheld(pDbFd) );
  unixEnterMutex();
  assert( pShmNode->nRef>0 );
  pShmNode->nRef--;
  if( pShmNode->nRef==0 ){
    if( deleteFlag && pShmNode->h>=0 ){
      osUnlink(pShmNode->zFilename);
    }

  unixUnlock,               /* xUnlock method */
  unixCheckReservedLock,    /* xCheckReservedLock method */
  unixShmMap                /* xShmMap method */
)
IOMETHODS(
  nolockIoFinder,           /* Finder function name */
  nolockIoMethods,          /* sqlite3_io_methods object name */
  3,                        /* shared memory is disabled */
  3,                        /* shared memory and mmap are enabled */
  nolockClose,              /* xClose method */
  nolockLock,               /* xLock method */
  nolockUnlock,             /* xUnlock method */
  nolockCheckReservedLock,  /* xCheckReservedLock method */
  0                         /* xShmMap method */
)
IOMETHODS(

  ** almost certain that an open() call on the same path will also fail.
  ** For this reason, if an error occurs in the stat() call here, it is
  ** ignored and -1 is returned. The caller will try to open a new file
  ** descriptor on the same path, fail, and return an error to SQLite.
  **
  ** Even if a subsequent open() call does succeed, the consequences of
  ** not searching for a reusable file descriptor are not dire.  */
  if( nUnusedFd>0 && 0==osStat(zPath, &sStat) ){
  if( inodeList!=0 && 0==osStat(zPath, &sStat) ){
    unixInodeInfo *pInode;

    pInode = inodeList;
    while( pInode && (pInode->fileId.dev!=sStat.st_dev
                     || pInode->fileId.ino!=(u64)sStat.st_ino) ){
       pInode = pInode->pNext;
    }
    if( pInode ){
      UnixUnusedFd **pp;
      assert( sqlite3_mutex_notheld(pInode->pLockMutex) );
      sqlite3_mutex_enter(pInode->pLockMutex);
      for(pp=&pInode->pUnused; *pp && (*pp)->flags!=flags; pp=&((*pp)->pNext));
      pUnused = *pp;
      if( pUnused ){
        nUnusedFd--;
        *pp = pUnused->pNext;
      }
      sqlite3_mutex_leave(pInode->pLockMutex);
    }
  }
  unixLeaveMutex();
#endif    /* if !OS_VXWORKS */
  return pUnused;
}

void sqlite3VdbeRunOnlyOnce(Vdbe*);
void sqlite3VdbeReusable(Vdbe*);
void sqlite3VdbeDelete(Vdbe*);
void sqlite3VdbeClearObject(sqlite3*,Vdbe*);
void sqlite3VdbeMakeReady(Vdbe*,Parse*);
int sqlite3VdbeFinalize(Vdbe*);
void sqlite3VdbeResolveLabel(Vdbe*, int);
#ifdef SQLITE_COVERAGE_TEST
  int sqlite3VdbeLabelHasBeenResolved(Vdbe*,int);
#endif
int sqlite3VdbeCurrentAddr(Vdbe*);
#ifdef SQLITE_DEBUG
  int sqlite3VdbeAssertMayAbort(Vdbe *, int);
#endif
void sqlite3VdbeResetStepResult(Vdbe*);
void sqlite3VdbeRewind(Vdbe*);
int sqlite3VdbeReset(Vdbe*);

    }
#endif
    assert( p->aLabel[j]==(-1) ); /* Labels may only be resolved once */
    p->aLabel[j] = v->nOp;
  }
}

#ifdef SQLITE_COVERAGE_TEST
/*
** Return TRUE if and only if the label x has already been resolved.
** Return FALSE (zero) if label x is still unresolved.
**
** This routine is only used inside of testcase() macros, and so it
** only exists when measuring test coverage.
*/
int sqlite3VdbeLabelHasBeenResolved(Vdbe *v, int x){
  return v->pParse->aLabel && v->pParse->aLabel[ADDR(x)]>=0;
}
#endif /* SQLITE_COVERAGE_TEST */

/*
** Mark the VDBE as one that can only be run one time.
*/
void sqlite3VdbeRunOnlyOnce(Vdbe *p){
  p->runOnlyOnce = 1;
}

  PRAGMA integrity_check;
} {ok}
do_execsql_test upsert1-610 {
  DELETE FROM t1;
  INSERT OR IGNORE INTO t1(a) VALUES('1'),(1) ON CONFLICT(a) DO NOTHING;
  PRAGMA integrity_check;
} {ok}

# 2018-08-14
# Ticket https://www.sqlite.org/src/info/908f001483982c43
# If there are multiple uniqueness contraints, the UPSERT should fire
# if the one constraint it targets fails, regardless of whether or not
# the other constraints pass or fail.  In other words, the UPSERT constraint
# should be tested first.
#
do_execsql_test upsert1-700 {
  DROP TABLE t1;
  CREATE TABLE t1(a INTEGER PRIMARY KEY, b INT, c INT, d INT, e INT);
  CREATE UNIQUE INDEX t1b ON t1(b);
  CREATE UNIQUE INDEX t1e ON t1(e);
  INSERT INTO t1(a,b,c,d,e) VALUES(1,2,3,4,5);
  INSERT INTO t1(a,b,c,d,e) VALUES(1,2,33,44,5)
    ON CONFLICT(e) DO UPDATE SET c=excluded.c;
  SELECT * FROM t1;
} {1 2 33 4 5}
do_execsql_test upsert1-710 {
  DELETE FROM t1;
  INSERT INTO t1(a,b,c,d,e) VALUES(1,2,3,4,5);
  INSERT INTO t1(a,b,c,d,e) VALUES(1,2,33,44,5)
    ON CONFLICT(a) DO UPDATE SET c=excluded.c;
  SELECT * FROM t1;
} {1 2 33 4 5}
do_execsql_test upsert1-720 {
  DELETE FROM t1;
  INSERT INTO t1(a,b,c,d,e) VALUES(1,2,3,4,5);
  INSERT INTO t1(a,b,c,d,e) VALUES(1,2,33,44,5)
    ON CONFLICT(b) DO UPDATE SET c=excluded.c;
  SELECT * FROM t1;
} {1 2 33 4 5}
do_execsql_test upsert1-730 {
  DROP TABLE t1;
  CREATE TABLE t1(a INT, b INT, c INT, d INT, e INT);
  CREATE UNIQUE INDEX t1a ON t1(a);
  CREATE UNIQUE INDEX t1b ON t1(b);
  CREATE UNIQUE INDEX t1e ON t1(e);
  INSERT INTO t1(a,b,c,d,e) VALUES(1,2,3,4,5);
  INSERT INTO t1(a,b,c,d,e) VALUES(1,2,33,44,5)
    ON CONFLICT(e) DO UPDATE SET c=excluded.c;
  SELECT * FROM t1;
} {1 2 33 4 5}
do_execsql_test upsert1-740 {
  DELETE FROM t1;
  INSERT INTO t1(a,b,c,d,e) VALUES(1,2,3,4,5);
  INSERT INTO t1(a,b,c,d,e) VALUES(1,2,33,44,5)
    ON CONFLICT(a) DO UPDATE SET c=excluded.c;
  SELECT * FROM t1;
} {1 2 33 4 5}
do_execsql_test upsert1-750 {
  DELETE FROM t1;
  INSERT INTO t1(a,b,c,d,e) VALUES(1,2,3,4,5);
  INSERT INTO t1(a,b,c,d,e) VALUES(1,2,33,44,5)
    ON CONFLICT(b) DO UPDATE SET c=excluded.c;
  SELECT * FROM t1;
} {1 2 33 4 5}
do_execsql_test upsert1-760 {
  DROP TABLE t1;
  CREATE TABLE t1(a INT PRIMARY KEY, b INT, c INT, d INT, e INT) WITHOUT ROWID;
  CREATE UNIQUE INDEX t1a ON t1(a);
  CREATE UNIQUE INDEX t1b ON t1(b);
  CREATE UNIQUE INDEX t1e ON t1(e);
  INSERT INTO t1(a,b,c,d,e) VALUES(1,2,3,4,5);
  INSERT INTO t1(a,b,c,d,e) VALUES(1,2,33,44,5)
    ON CONFLICT(e) DO UPDATE SET c=excluded.c;
  SELECT * FROM t1;
} {1 2 33 4 5}
do_execsql_test upsert1-770 {
  DELETE FROM t1;
  INSERT INTO t1(a,b,c,d,e) VALUES(1,2,3,4,5);
  INSERT INTO t1(a,b,c,d,e) VALUES(1,2,33,44,5)
    ON CONFLICT(a) DO UPDATE SET c=excluded.c;
  SELECT * FROM t1;
} {1 2 33 4 5}
do_execsql_test upsert1-780 {
  DELETE FROM t1;
  INSERT INTO t1(a,b,c,d,e) VALUES(1,2,3,4,5);
  INSERT INTO t1(a,b,c,d,e) VALUES(1,2,33,44,5)
    ON CONFLICT(b) DO UPDATE SET c=excluded.c;
  SELECT * FROM t1;
} {1 2 33 4 5}


finish_test