** the text of this file.  Search for "Begin file sqlite3.h" to find the start
** of the embedded sqlite3.h header file.) Additional code files may be needed
** if you want a wrapper to interface SQLite with your choice of programming
** language. The code for the "sqlite3" command-line shell is also in a
** separate file. This file contains only code for the core SQLite library.
**
** The content in this amalgamation comes from Fossil check-in
** cf7163f82ca380958a79350473b2c5a2cebd with changes in files:
** 0f31711591c56f3896fb6f092752fb82c4ea with changes in files:
**
**    
*/
#ifndef SQLITE_AMALGAMATION
#define SQLITE_CORE 1
#define SQLITE_AMALGAMATION 1
#ifndef SQLITE_PRIVATE

**
** See also: [sqlite3_libversion()],
** [sqlite3_libversion_number()], [sqlite3_sourceid()],
** [sqlite_version()] and [sqlite_source_id()].
*/
#define SQLITE_VERSION        "3.51.0"
#define SQLITE_VERSION_NUMBER 3051000
#define SQLITE_SOURCE_ID      "2025-07-30 16:17:14 cf7163f82ca380958a79350473b2c5a2cebda7496d6d575fa2835c362010fea1"
#define SQLITE_SOURCE_ID      "2025-09-09 10:28:06 0f31711591c56f3896fb6f092752fb82c4ea646bf8e5838dfbe55302994ea091"
#define SQLITE_SCM_BRANCH     "trunk"
#define SQLITE_SCM_TAGS       ""
#define SQLITE_SCM_DATETIME   "2025-09-09T10:28:06.692Z"

/*
** CAPI3REF: Run-Time Library Version Numbers
** KEYWORDS: sqlite3_version sqlite3_sourceid
**
** These interfaces provide the same information as the [SQLITE_VERSION],
** [SQLITE_VERSION_NUMBER], and [SQLITE_SOURCE_ID] C preprocessor macros

** SQLite version 3.35.0, TEMP views are still allowed even if
** this option is off.  So, in other words, this option now only disables
** views in the main database schema or in the schemas of ATTACH-ed
** databases.)^ </dd>
**
** [[SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER]]
** <dt>SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER</dt>
** <dd> ^This option is used to enable or disable the
** [fts3_tokenizer()] function which is part of the
** [FTS3] full-text search engine extension.
** There must be two additional arguments.
** The first argument is an integer which is 0 to disable fts3_tokenizer() or
** positive to enable fts3_tokenizer() or negative to leave the setting
** <dd> ^This option is used to enable or disable using the
** [fts3_tokenizer()] function - part of the [FTS3] full-text search engine
** extension - without using bound parameters as the parameters. Doing so
** is disabled by default. There must be two additional arguments. The first
** argument is an integer. If it is passed 0, then using fts3_tokenizer()
** without bound parameters is disabled. If it is passed a positive value,
** then calling fts3_tokenizer without bound parameters is enabled. If it
** unchanged.
** The second parameter is a pointer to an integer into which
** is written 0 or 1 to indicate whether fts3_tokenizer is disabled or enabled
** following this call.  The second parameter may be a NULL pointer, in
** which case the new setting is not reported back. </dd>
** is passed a negative value, this setting is not modified - this can be
** used to query for the current setting. The second parameter is a pointer
** to an integer into which is written 0 or 1 to indicate the current value
** of this setting (after it is modified, if applicable).  The second
** parameter may be a NULL pointer, in which case the value of the setting
** is not reported back. Refer to [FTS3] documentation for further details.
** </dd>
**
** [[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION]]
** <dt>SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION</dt>
** <dd> ^This option is used to enable or disable the [sqlite3_load_extension()]
** interface independently of the [load_extension()] SQL function.
** The [sqlite3_enable_load_extension()] API enables or disables both the
** C-API [sqlite3_load_extension()] and the SQL function [load_extension()].

** with a [database connection].
** A call to sqlite3_set_clientdata(D,N,P,X) causes the pointer P
** to be attached to [database connection] D using name N.  Subsequent
** calls to sqlite3_get_clientdata(D,N) will return a copy of pointer P
** or a NULL pointer if there were no prior calls to
** sqlite3_set_clientdata() with the same values of D and N.
** Names are compared using strcmp() and are thus case sensitive.
** It returns 0 on success and SQLITE_NOMEM on allocation failure.
**
** If P and X are both non-NULL, then the destructor X is invoked with
** argument P on the first of the following occurrences:
** <ul>
** <li> An out-of-memory error occurs during the call to
**      sqlite3_set_clientdata() which attempts to register pointer P.
** <li> A subsequent call to sqlite3_set_clientdata(D,N,P,X) is made

** is a copy of the third parameter passed to sqlite3_wal_hook() when
** registering the callback. ^The second is a copy of the database handle.
** ^The third parameter is the name of the database that was written to -
** either "main" or the name of an [ATTACH]-ed database. ^The fourth parameter
** is the number of pages currently in the write-ahead log file,
** including those that were just committed.
**
** The callback function should normally return [SQLITE_OK].  ^If an error
** ^The callback function should normally return [SQLITE_OK].  ^If an error
** code is returned, that error will propagate back up through the
** SQLite code base to cause the statement that provoked the callback
** to report an error, though the commit will have still occurred. If the
** callback returns [SQLITE_ROW] or [SQLITE_DONE], or if it returns a value
** that does not correspond to any valid SQLite error code, the results
** are undefined.
**
** A single database handle may have at most a single write-ahead log callback
** registered at one time. ^Calling [sqlite3_wal_hook()] replaces any
** previously registered write-ahead log callback. ^The return value is
** a copy of the third parameter from the previous call, if any, or 0.
** ^Note that the [sqlite3_wal_autocheckpoint()] interface and the
** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and will
** overwrite any prior [sqlite3_wal_hook()] settings.
** ^A single database handle may have at most a single write-ahead log
** callback registered at one time. ^Calling [sqlite3_wal_hook()]
** replaces the default behavior or previously registered write-ahead
** log callback.
**
** ^The return value is a copy of the third parameter from the
** previous call, if any, or 0.
**
** ^The [sqlite3_wal_autocheckpoint()] interface and the
** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and
** will overwrite any prior [sqlite3_wal_hook()] settings.
**
** ^If a write-ahead log callback is set using this function then
** [sqlite3_wal_checkpoint_v2()] or [PRAGMA wal_checkpoint]
** should be invoked periodically to keep the write-ahead log file
** from growing without bound.
**
** ^Passing a NULL pointer for the callback disables automatic
** checkpointing entirely. To re-enable the default behavior, call
** sqlite3_wal_autocheckpoint(db,1000) or use [PRAGMA wal_checkpoint].
*/
SQLITE_API void *sqlite3_wal_hook(
  sqlite3*,
  int(*)(void *,sqlite3*,const char*,int),
  void*
);

/*
** CAPI3REF: Configure an auto-checkpoint
** METHOD: sqlite3
**
** ^The [sqlite3_wal_autocheckpoint(D,N)] is a wrapper around
** [sqlite3_wal_hook()] that causes any database on [database connection] D
** to automatically [checkpoint]
** after committing a transaction if there are N or
** more frames in the [write-ahead log] file.  ^Passing zero or
** a negative value as the nFrame parameter disables automatic
** a negative value as the N parameter disables automatic
** checkpoints entirely.
**
** ^The callback registered by this function replaces any existing callback
** registered using [sqlite3_wal_hook()].  ^Likewise, registering a callback
** using [sqlite3_wal_hook()] disables the automatic checkpoint mechanism
** configured by this function.
**
** ^The [wal_autocheckpoint pragma] can be used to invoke this interface
** from SQL.
**
** ^Checkpoints initiated by this mechanism are
** [sqlite3_wal_checkpoint_v2|PASSIVE].
**
** ^Every new [database connection] defaults to having the auto-checkpoint
** enabled with a threshold of 1000 or [SQLITE_DEFAULT_WAL_AUTOCHECKPOINT]
** pages.  The use of this interface
** is only necessary if the default setting is found to be suboptimal
** for a particular application.
** pages.
**
** ^The use of this interface is only necessary if the default setting
** is found to be suboptimal for a particular application.
*/
SQLITE_API int sqlite3_wal_autocheckpoint(sqlite3 *db, int N);

/*
** CAPI3REF: Checkpoint a database
** METHOD: sqlite3
**

**   ^Like SQLITE_CHECKPOINT_FULL, this mode blocks new
**   database writer attempts while it is pending, but does not impede readers.
**
** <dt>SQLITE_CHECKPOINT_TRUNCATE<dd>
**   ^This mode works the same way as SQLITE_CHECKPOINT_RESTART with the
**   addition that it also truncates the log file to zero bytes just prior
**   to a successful return.
**
** <dt>SQLITE_CHECKPOINT_NOOP<dd>
**   ^This mode always checkpoints zero frames. The only reason to invoke
**   a NOOP checkpoint is to access the values returned by
**   sqlite3_wal_checkpoint_v2() via output parameters *pnLog and *pnCkpt.
** </dl>
**
** ^If pnLog is not NULL, then *pnLog is set to the total number of frames in
** the log file or to -1 if the checkpoint could not run because
** of an error or because the database is not in [WAL mode]. ^If pnCkpt is not
** NULL,then *pnCkpt is set to the total number of checkpointed frames in the
** log file (including any that were already checkpointed before the function

** KEYWORDS: {checkpoint mode}
**
** These constants define all valid values for the "checkpoint mode" passed
** as the third parameter to the [sqlite3_wal_checkpoint_v2()] interface.
** See the [sqlite3_wal_checkpoint_v2()] documentation for details on the
** meaning of each of these checkpoint modes.
*/
#define SQLITE_CHECKPOINT_NOOP    -1  /* Do no work at all */
#define SQLITE_CHECKPOINT_PASSIVE  0  /* Do as much as possible w/o blocking */
#define SQLITE_CHECKPOINT_FULL     1  /* Wait for writers, then checkpoint */
#define SQLITE_CHECKPOINT_RESTART  2  /* Like FULL but wait for readers */
#define SQLITE_CHECKPOINT_TRUNCATE 3  /* Like RESTART but also truncate WAL */

/*
** CAPI3REF: Virtual Table Interface Configuration

** The [sqlite3_snapshot] object returned from a successful call to
** [sqlite3_snapshot_get()] must be freed using [sqlite3_snapshot_free()]
** to avoid a memory leak.
**
** The [sqlite3_snapshot_get()] interface is only available when the
** [SQLITE_ENABLE_SNAPSHOT] compile-time option is used.
*/
SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_snapshot_get(
SQLITE_API int sqlite3_snapshot_get(
  sqlite3 *db,
  const char *zSchema,
  sqlite3_snapshot **ppSnapshot
);

/*
** CAPI3REF: Start a read transaction on an historical snapshot

** after the most recent I/O on the database connection.)^
** (Hint: Run "[PRAGMA application_id]" against a newly opened
** database connection in order to make it ready to use snapshots.)
**
** The [sqlite3_snapshot_open()] interface is only available when the
** [SQLITE_ENABLE_SNAPSHOT] compile-time option is used.
*/
SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_snapshot_open(
SQLITE_API int sqlite3_snapshot_open(
  sqlite3 *db,
  const char *zSchema,
  sqlite3_snapshot *pSnapshot
);

/*
** CAPI3REF: Destroy a snapshot
** DESTRUCTOR: sqlite3_snapshot
**
** ^The [sqlite3_snapshot_free(P)] interface destroys [sqlite3_snapshot] P.
** The application must eventually free every [sqlite3_snapshot] object
** using this routine to avoid a memory leak.
**
** The [sqlite3_snapshot_free()] interface is only available when the
** [SQLITE_ENABLE_SNAPSHOT] compile-time option is used.
*/
SQLITE_API SQLITE_EXPERIMENTAL void sqlite3_snapshot_free(sqlite3_snapshot*);
SQLITE_API void sqlite3_snapshot_free(sqlite3_snapshot*);

/*
** CAPI3REF: Compare the ages of two snapshot handles.
** METHOD: sqlite3_snapshot
**
** The sqlite3_snapshot_cmp(P1, P2) interface is used to compare the ages
** of two valid snapshot handles.

** Otherwise, this API returns a negative value if P1 refers to an older
** snapshot than P2, zero if the two handles refer to the same database
** snapshot, and a positive value if P1 is a newer snapshot than P2.
**
** This interface is only available if SQLite is compiled with the
** [SQLITE_ENABLE_SNAPSHOT] option.
*/
SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_snapshot_cmp(
SQLITE_API int sqlite3_snapshot_cmp(
  sqlite3_snapshot *p1,
  sqlite3_snapshot *p2
);

/*
** CAPI3REF: Recover snapshots from a wal file
** METHOD: sqlite3_snapshot

** database.
**
** SQLITE_OK is returned if successful, or an SQLite error code otherwise.
**
** This interface is only available if SQLite is compiled with the
** [SQLITE_ENABLE_SNAPSHOT] option.
*/
SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_snapshot_recover(sqlite3 *db, const char *zDb);
SQLITE_API int sqlite3_snapshot_recover(sqlite3 *db, const char *zDb);

/*
** CAPI3REF: Serialize a database
**
** The sqlite3_serialize(D,S,P,F) interface returns a pointer to
** memory that is a serialization of the S database on
** [database connection] D.  If S is a NULL pointer, the main database is used.

#define SQLITE_SERIALIZE_NOCOPY 0x001   /* Do no memory allocations */

/*
** CAPI3REF: Deserialize a database
**
** The sqlite3_deserialize(D,S,P,N,M,F) interface causes the
** [database connection] D to disconnect from database S and then
** reopen S as an in-memory database based on the serialization contained
** in P.  The serialized database P is N bytes in size.  M is the size of
** the buffer P, which might be larger than N.  If M is larger than N, and
** the SQLITE_DESERIALIZE_READONLY bit is not set in F, then SQLite is
** permitted to add content to the in-memory database as long as the total
** size does not exceed M bytes.
** reopen S as an in-memory database based on the serialization
** contained in P.  If S is a NULL pointer, the main database is
** used. The serialized database P is N bytes in size.  M is the size
** of the buffer P, which might be larger than N.  If M is larger than
** N, and the SQLITE_DESERIALIZE_READONLY bit is not set in F, then
** SQLite is permitted to add content to the in-memory database as
** long as the total size does not exceed M bytes.
**
** If the SQLITE_DESERIALIZE_FREEONCLOSE bit is set in F, then SQLite will
** invoke sqlite3_free() on the serialization buffer when the database
** connection closes.  If the SQLITE_DESERIALIZE_RESIZEABLE bit is set, then
** SQLite will try to increase the buffer size using sqlite3_realloc64()
** if writes on the database cause it to grow larger than M bytes.
**

#endif


/*
** Maximum number of pages in one database file.
**
** This is really just the default value for the max_page_count pragma.
** This value can be lowered (or raised) at run-time using that the
** This value can be lowered (or raised) at run-time using the
** max_page_count macro.
*/
#ifndef SQLITE_MAX_PAGE_COUNT
# define SQLITE_MAX_PAGE_COUNT 0xfffffffe /* 4294967294 */
#endif

/*

#define SF_UFSrcCheck    0x0800000 /* Check pSrc as required by UPDATE...FROM */
#define SF_PushDown      0x1000000 /* Modified by WHERE-clause push-down opt */
#define SF_MultiPart     0x2000000 /* Has multiple incompatible PARTITIONs */
#define SF_CopyCte       0x4000000 /* SELECT statement is a copy of a CTE */
#define SF_OrderByReqd   0x8000000 /* The ORDER BY clause may not be omitted */
#define SF_UpdateFrom   0x10000000 /* Query originates with UPDATE FROM */
#define SF_Correlated   0x20000000 /* True if references the outer context */
#define SF_OnToWhere    0x40000000 /* One or more ON clauses moved to WHERE */

/* True if SrcItem X is a subquery that has SF_NestedFrom */
#define IsNestedFrom(X) \
   ((X)->fg.isSubquery && \
    ((X)->u4.pSubq->pSelect->selFlags&SF_NestedFrom)!=0)

/*

    struct WhereConst *pConst;                /* WHERE clause constants */
    struct RenameCtx *pRename;                /* RENAME COLUMN context */
    struct Table *pTab;                       /* Table of generated column */
    struct CoveringIndexCheck *pCovIdxCk;     /* Check for covering index */
    SrcItem *pSrcItem;                        /* A single FROM clause item */
    DbFixer *pFix;                            /* See sqlite3FixSelect() */
    Mem *aMem;                                /* See sqlite3BtreeCursorHint() */
    struct CheckOnCtx *pCheckOnCtx;           /* See selectCheckOnClauses() */
  } u;
};

/*
** The following structure contains information used by the sqliteFix...
** routines as they walk the parse tree to make database references
** explicit.

  i64 iKey1;                      /* First key value passed to hook */
  i64 iKey2;                      /* Second key value passed to hook */
  Mem oldipk;                     /* Memory cell holding "old" IPK value */
  Mem *aNew;                      /* Array of new.* values */
  Table *pTab;                    /* Schema object being updated */
  Index *pPk;                     /* PK index if pTab is WITHOUT ROWID */
  sqlite3_value **apDflt;         /* Array of default values, if required */
  union {
    KeyInfo sKey;
  u8 keyinfoSpace[SZ_KEYINFO_0];  /* Space to hold pKeyinfo[0] content */
    u8 keyinfoSpace[SZ_KEYINFO_0];  /* Space to hold pKeyinfo[0] content */
  } uKey;
};

/*
** An instance of this object is used to pass an vector of values into
** OP_VFilter, the xFilter method of a virtual table.  The vector is the
** set of values on the right-hand side of an IN constraint.
**

    if( pItem->fg.isSubquery )     sqlite3_str_appendf(&x, " isSubquery");

    sqlite3StrAccumFinish(&x);
    sqlite3TreeViewItem(pView, zLine, i<pSrc->nSrc-1);
    n = 0;
    if( pItem->fg.isSubquery ) n++;
    if( pItem->fg.isTabFunc ) n++;
    if( pItem->fg.isUsing ) n++;
    if( pItem->fg.isUsing || pItem->u3.pOn!=0 ) n++;
    if( pItem->fg.isUsing ){
      sqlite3TreeViewIdList(pView, pItem->u3.pUsing, (--n)>0, "USING");
    }else if( pItem->u3.pOn!=0 ){
      sqlite3TreeViewItem(pView, "ON", (--n)>0);
      sqlite3TreeViewExpr(pView, pItem->u3.pOn, 0);
      sqlite3TreeViewPop(&pView);
    }
    if( pItem->fg.isSubquery ){
      assert( n==1 );
      if( pItem->pSTab ){
        Table *pTab = pItem->pSTab;
        sqlite3TreeViewColumnList(pView, pTab->aCol, pTab->nCol, 1);
      }

  { "pwrite64",     (sqlite3_syscall_ptr)0,          0  },
#endif
#define osPwrite64  ((ssize_t(*)(int,const void*,size_t,off64_t))\
                    aSyscall[13].pCurrent)

#if defined(HAVE_FCHMOD)
  { "fchmod",       (sqlite3_syscall_ptr)fchmod,          0  },
#define osFchmod    ((int(*)(int,mode_t))aSyscall[14].pCurrent)
#else
  { "fchmod",       (sqlite3_syscall_ptr)0,               0  },
#define osFchmod(FID,MODE) 0
#endif
#define osFchmod    ((int(*)(int,mode_t))aSyscall[14].pCurrent)

#if defined(HAVE_POSIX_FALLOCATE) && HAVE_POSIX_FALLOCATE
  { "fallocate",    (sqlite3_syscall_ptr)posix_fallocate,  0 },
#else
  { "fallocate",    (sqlite3_syscall_ptr)0,                0 },
#endif
#define osFallocate ((int(*)(int,off_t,off_t))aSyscall[15].pCurrent)

  */
  if( statbuf.st_size==0 && (pFile->fsFlags & SQLITE_FSFLAGS_IS_MSDOS)!=0 ){
    do{ rc = osWrite(fd, "S", 1); }while( rc<0 && errno==EINTR );
    if( rc!=1 ){
      storeLastErrno(pFile, errno);
      return SQLITE_IOERR;
    }
    if( fsync(fd) ){
      storeLastErrno(pFile, errno);
      return SQLITE_IOERR_FSYNC;
    }
    rc = osFstat(fd, &statbuf);
    if( rc!=0 ){
      storeLastErrno(pFile, errno);
      return SQLITE_IOERR;
    }
  }
#endif

# define osSetPosixAdvisoryLock(h,x,t) osFcntl(h,F_SETLK,x)
#else
static int osSetPosixAdvisoryLock(
  int h,                /* The file descriptor on which to take the lock */
  struct flock *pLock,  /* The description of the lock */
  unixFile *pFile       /* Structure holding timeout value */
){
  int rc = 0;

  int tm = pFile->iBusyTimeout;
  int rc = osFcntl(h,F_SETLK,pLock);
  if( pFile->iBusyTimeout==0 ){
    /* unixFile->iBusyTimeout is set to 0. In this case, attempt a
    ** non-blocking lock. */
    rc = osFcntl(h,F_SETLK,pLock);
  while( rc<0 && tm>0 ){
    /* On systems that support some kind of blocking file lock with a timeout,
  }else{
    /* unixFile->iBusyTimeout is set to greater than zero. In this case,
    ** attempt a blocking-lock with a unixFile->iBusyTimeout ms timeout.
    **
    ** On systems that support some kind of blocking file lock operation,
    ** make appropriate changes here to invoke that blocking file lock.  On
    ** generic posix, however, there is no such API.  So we simply try the
    ** lock once every millisecond until either the timeout expires, or until
    ** the lock is obtained. */
    unixSleep(0,1000);
    rc = osFcntl(h,F_SETLK,pLock);
    tm--;
  }
    ** this block should be replaced by code to attempt a blocking lock
    ** with a timeout of unixFile->iBusyTimeout ms. The code below is
    ** placeholder code. If SQLITE_TEST is defined, the placeholder code
    ** retries the lock once every 1ms until it succeeds or the timeout
    ** is reached. Or, if SQLITE_TEST is not defined, the placeholder
    ** code attempts a non-blocking lock and sets unixFile->iBusyTimeout
    ** to 0. This causes the caller to return SQLITE_BUSY, instead of
    ** SQLITE_BUSY_TIMEOUT to SQLite - as required by a VFS that does not
    ** support blocking locks.
    */
#ifdef SQLITE_TEST
    int tm = pFile->iBusyTimeout;
    while( tm>0 ){
      rc = osFcntl(h,F_SETLK,pLock);
      if( rc==0 ) break;
      unixSleep(0,1000);
      tm--;
    }
#else
    rc = osFcntl(h,F_SETLK,pLock);
    pFile->iBusyTimeout = 0;
#endif
    /* End of code to replace with real blocking-locks code. */
  }

  return rc;
}
#endif /* SQLITE_ENABLE_SETLK_TIMEOUT */


/*
** Attempt to set a system-lock on the file pFile.  The lock is

** Object used to represent a single file opened and mmapped to provide
** shared memory.  When multiple threads all reference the same
** log-summary, each thread has its own winFile object, but they all
** point to a single instance of this object.  In other words, each
** log-summary is opened only once per process.
**
** winShmMutexHeld() must be true when creating or destroying
** this object or while reading or writing the following fields:
** this object, or while editing the global linked list that starts
** at winShmNodeList.
**
** When reading or writing the linked list starting at winShmNode.pWinShmList,
**      nRef
** pShmNode->mutex must be held.
**      pNext
**
** The following fields are read-only after the object is created:
** The following fields are constant after the object is created:
**
**      zFilename
**      hSharedShm
**      mutex
**      bUseSharedLockHandle
**
** Either winShmNode.mutex must be held or winShmNode.nRef==0 and
** Either winShmNode.mutex must be held or winShmNode.pWinShmList==0 and
** winShmMutexHeld() is true when reading or writing any other field
** in this structure.
**
** File-handle hSharedShm is used to (a) take the DMS lock, (b) truncate
** the *-shm file if the DMS-locking protocol demands it, and (c) map
** regions of the *-shm file into memory using MapViewOfFile() or
** similar. Other locks are taken by individual clients using the
** winShm.hShm handles.
** File-handle hSharedShm is always used to (a) take the DMS lock, (b)
** truncate the *-shm file if the DMS-locking protocol demands it, and
** (c) map regions of the *-shm file into memory using MapViewOfFile()
** or similar. If bUseSharedLockHandle is true, then other locks are also
** taken on hSharedShm. Or, if bUseSharedLockHandle is false, then other
** locks are taken using each connection's winShm.hShm handles.
*/
struct winShmNode {
  sqlite3_mutex *mutex;      /* Mutex to access this object */
  char *zFilename;           /* Name of the file */
  HANDLE hSharedShm;         /* File handle open on zFilename */
  int bUseSharedLockHandle;  /* True to use hSharedShm for everything */

  int isUnlocked;            /* DMS lock has not yet been obtained */
  int isReadonly;            /* True if read-only */
  int szRegion;              /* Size of shared-memory regions */
  int nRegion;               /* Size of array apRegion */

  struct ShmRegion {
    HANDLE hMap;             /* File handle from CreateFileMapping */
    void *pMap;
  } *aRegion;
  DWORD lastErrno;           /* The Windows errno from the last I/O error */

  winShm *pWinShmList;       /* List of winShm objects with ptrs to this */
  int nRef;                  /* Number of winShm objects pointing to this */

  winShmNode *pNext;         /* Next in list of all winShmNode objects */
#if defined(SQLITE_DEBUG) || defined(SQLITE_HAVE_OS_TRACE)
  u8 nextShmId;              /* Next available winShm.id value */
#endif
};

/*

  u16 sharedMask;            /* Mask of shared locks held */
  u16 exclMask;              /* Mask of exclusive locks held */
  HANDLE hShm;               /* File-handle on *-shm file. For locking. */
  int bReadonly;             /* True if hShm is opened read-only */
#if defined(SQLITE_DEBUG) || defined(SQLITE_HAVE_OS_TRACE)
  u8 id;                     /* Id of this connection with its winShmNode */
#endif
  winShm *pWinShmNext;       /* Next winShm object on same winShmNode */
};

/*
** Constants used for locking
*/
#define WIN_SHM_BASE   ((22+SQLITE_SHM_NLOCK)*4)        /* first lock byte */
#define WIN_SHM_DMS    (WIN_SHM_BASE+SQLITE_SHM_NLOCK)  /* deadman switch */

/* Forward references to VFS methods */
static int winOpen(sqlite3_vfs*,const char*,sqlite3_file*,int,int*);
static int winDelete(sqlite3_vfs *,const char*,int);

/*
** Purge the winShmNodeList list of all entries with winShmNode.nRef==0.
** Purge the winShmNodeList list of all entries with winShmNode.pWinShmList==0.
**
** This is not a VFS shared-memory method; it is a utility function called
** by VFS shared-memory methods.
*/
static void winShmPurge(sqlite3_vfs *pVfs, int deleteFlag){
  winShmNode **pp;
  winShmNode *p;
  assert( winShmMutexHeld() );
  OSTRACE(("SHM-PURGE pid=%lu, deleteFlag=%d\n",
           osGetCurrentProcessId(), deleteFlag));
  pp = &winShmNodeList;
  while( (p = *pp)!=0 ){
    if( p->nRef==0 ){
    if( p->pWinShmList==0 ){
      int i;
      if( p->mutex ){ sqlite3_mutex_free(p->mutex); }
      for(i=0; i<p->nRegion; i++){
        BOOL bRc = osUnmapViewOfFile(p->aRegion[i].pMap);
        OSTRACE(("SHM-PURGE-UNMAP pid=%lu, region=%d, rc=%s\n",
                 osGetCurrentProcessId(), i, bRc ? "ok" : "failed"));
        UNUSED_VARIABLE_VALUE(bRc);

 winopenfile_out:
  sqlite3_free(zConverted);
  *pbReadonly = bReadonly;
  *ph = h;
  return rc;
}

/*
** Close pDbFd's connection to shared-memory.  Delete the underlying
** *-shm file if deleteFlag is true.
*/
static int winCloseSharedMemory(winFile *pDbFd, int deleteFlag){
  winShm *p;            /* The connection to be closed */
  winShm **pp;          /* Iterator for pShmNode->pWinShmList */
  winShmNode *pShmNode; /* The underlying shared-memory file */

  p = pDbFd->pShm;
  if( p==0 ) return SQLITE_OK;
  if( p->hShm!=INVALID_HANDLE_VALUE ){
    osCloseHandle(p->hShm);
  }

  winShmEnterMutex();
  pShmNode = p->pShmNode;

  /* Remove this connection from the winShmNode.pWinShmList list */
  sqlite3_mutex_enter(pShmNode->mutex);
  for(pp=&pShmNode->pWinShmList; *pp!=p; pp=&(*pp)->pWinShmNext){}
  *pp = p->pWinShmNext;
  sqlite3_mutex_leave(pShmNode->mutex);

  winShmPurge(pDbFd->pVfs, deleteFlag);
  winShmLeaveMutex();

  /* Free the connection p */
  sqlite3_free(p);
  pDbFd->pShm = 0;
  return SQLITE_OK;
}

/*
** testfixture builds may set this global variable to true via a
** Tcl interface. This forces the VFS to use the locking normally
** only used for UNC paths for all files.
*/
#ifdef SQLITE_TEST
SQLITE_API int sqlite3_win_test_unc_locking = 0;
#else
# define sqlite3_win_test_unc_locking 0
#endif

/*
** Return true if the string passed as the only argument is likely
** to be a UNC path. In other words, if it starts with "\\".
*/
static int winIsUNCPath(const char *zFile){
  if( zFile[0]=='\\' && zFile[1]=='\\' ){
    return 1;
  }
  return sqlite3_win_test_unc_locking;
}

/*
** Open the shared-memory area associated with database file pDbFd.
*/
static int winOpenSharedMemory(winFile *pDbFd){
  struct winShm *p;                  /* The connection to be opened */
  winShmNode *pShmNode = 0;          /* The underlying mmapped file */

  if( pNew==0 ){
    sqlite3_free(p);
    return SQLITE_IOERR_NOMEM_BKPT;
  }
  pNew->zFilename = (char*)&pNew[1];
  pNew->hSharedShm = INVALID_HANDLE_VALUE;
  pNew->isUnlocked = 1;
  pNew->bUseSharedLockHandle = winIsUNCPath(pDbFd->zPath);
  sqlite3_snprintf(nName+15, pNew->zFilename, "%s-shm", pDbFd->zPath);
  sqlite3FileSuffix3(pDbFd->zPath, pNew->zFilename);

  /* Open a file-handle on the *-shm file for this connection. This file-handle
  ** is only used for locking. The mapping of the *-shm file is created using
  ** the shared file handle in winShmNode.hSharedShm.  */
  p->bReadonly = sqlite3_uri_boolean(pDbFd->zPath, "readonly_shm", 0);
  rc = winHandleOpen(pNew->zFilename, &p->bReadonly, &p->hShm);

  /* Look to see if there is an existing winShmNode that can be used.
  ** If no matching winShmNode currently exists, then create a new one.  */
  winShmEnterMutex();
  for(pShmNode = winShmNodeList; pShmNode; pShmNode=pShmNode->pNext){
    /* TBD need to come up with better match here.  Perhaps
    ** use FILE_ID_BOTH_DIR_INFO Structure.  */
    if( sqlite3StrICmp(pShmNode->zFilename, pNew->zFilename)==0 ) break;
  }
  if( pShmNode==0 ){
    pShmNode = pNew;

    /* Allocate a mutex for this winShmNode object, if one is required. */
    if( sqlite3GlobalConfig.bCoreMutex ){
      pShmNode->mutex = sqlite3_mutex_alloc(SQLITE_MUTEX_FAST);
      if( pShmNode->mutex==0 ) rc = SQLITE_IOERR_NOMEM_BKPT;
    }

    /* Open a file-handle to use for mappings, and for the DMS lock. */
    if( rc==SQLITE_OK ){
      HANDLE h = INVALID_HANDLE_VALUE;
      pShmNode->isReadonly = p->bReadonly;
      pShmNode->isReadonly = sqlite3_uri_boolean(pDbFd->zPath,"readonly_shm",0);
      rc = winHandleOpen(pNew->zFilename, &pShmNode->isReadonly, &h);
      pShmNode->hSharedShm = h;
    }

    /* If successful, link the new winShmNode into the global list. If an
    ** error occurred, free the object. */
    if( rc==SQLITE_OK ){

      }
    }
  }

  /* If no error has occurred, link the winShm object to the winShmNode and
  ** the winShm to pDbFd.  */
  if( rc==SQLITE_OK ){
    sqlite3_mutex_enter(pShmNode->mutex);
    p->pShmNode = pShmNode;
    p->pWinShmNext = pShmNode->pWinShmList;
    pShmNode->nRef++;
    pShmNode->pWinShmList = p;
#if defined(SQLITE_DEBUG) || defined(SQLITE_HAVE_OS_TRACE)
    p->id = pShmNode->nextShmId++;
#endif
    pDbFd->pShm = p;
    sqlite3_mutex_leave(pShmNode->mutex);
  }else if( p ){
    winHandleClose(p->hShm);
    sqlite3_free(p);
  }

  assert( rc!=SQLITE_OK || pShmNode->isUnlocked==0 || pShmNode->nRegion==0 );
  winShmLeaveMutex();
  sqlite3_free(pNew);

  /* Open a file-handle on the *-shm file for this connection. This file-handle
  ** is only used for locking. The mapping of the *-shm file is created using
  ** the shared file handle in winShmNode.hSharedShm.  */
  if( rc==SQLITE_OK && pShmNode->bUseSharedLockHandle==0 ){
    p->bReadonly = sqlite3_uri_boolean(pDbFd->zPath, "readonly_shm", 0);
    rc = winHandleOpen(pShmNode->zFilename, &p->bReadonly, &p->hShm);
    if( rc!=SQLITE_OK ){
      assert( p->hShm==INVALID_HANDLE_VALUE );
      winCloseSharedMemory(pDbFd, 0);
    }
  }

  return rc;
}

/*
** Close a connection to shared-memory.  Delete the underlying
** storage if deleteFlag is true.
*/
static int winShmUnmap(
  sqlite3_file *fd,          /* Database holding shared memory */
  int deleteFlag             /* Delete after closing if true */
){
  winFile *pDbFd;       /* Database holding shared-memory */
  winShm *p;            /* The connection to be closed */
  winShmNode *pShmNode; /* The underlying shared-memory file */

  return winCloseSharedMemory((winFile*)fd, deleteFlag);
  pDbFd = (winFile*)fd;
  p = pDbFd->pShm;
  if( p==0 ) return SQLITE_OK;
  if( p->hShm!=INVALID_HANDLE_VALUE ){
    osCloseHandle(p->hShm);
  }

  pShmNode = p->pShmNode;
  winShmEnterMutex();

  /* If pShmNode->nRef has reached 0, then close the underlying
  ** shared-memory file, too. */
  assert( pShmNode->nRef>0 );
  pShmNode->nRef--;
  if( pShmNode->nRef==0 ){
    winShmPurge(pDbFd->pVfs, deleteFlag);
  }
  winShmLeaveMutex();

  /* Free the connection p */
  sqlite3_free(p);
  pDbFd->pShm = 0;
  return SQLITE_OK;
}

/*
** Change the lock state for a shared-memory segment.
*/
static int winShmLock(
  sqlite3_file *fd,          /* Database file holding the shared memory */

  assert( flags!=(SQLITE_SHM_EXCLUSIVE|SQLITE_SHM_LOCK)
       || 0==(p->exclMask & mask)
  );
  if( ((flags & SQLITE_SHM_UNLOCK) && ((p->exclMask|p->sharedMask) & mask))
   || (flags==(SQLITE_SHM_SHARED|SQLITE_SHM_LOCK) && 0==(p->sharedMask & mask))
   || (flags==(SQLITE_SHM_EXCLUSIVE|SQLITE_SHM_LOCK))
  ){
    HANDLE h = p->hShm;

    if( flags & SQLITE_SHM_UNLOCK ){
      /* Case (a) - unlock.  */

      assert( (p->exclMask & p->sharedMask)==0 );
      assert( !(flags & SQLITE_SHM_EXCLUSIVE) || (p->exclMask & mask)==mask );
      assert( !(flags & SQLITE_SHM_SHARED) || (p->sharedMask & mask)==mask );

      assert( !(flags & SQLITE_SHM_SHARED) || n==1 );
      if( pShmNode->bUseSharedLockHandle ){
        h = pShmNode->hSharedShm;
        if( flags & SQLITE_SHM_SHARED ){
          winShm *pShm;
          sqlite3_mutex_enter(pShmNode->mutex);
          for(pShm=pShmNode->pWinShmList; pShm; pShm=pShm->pWinShmNext){
            if( pShm!=p && (pShm->sharedMask & mask) ){
              /* Another connection within this process is also holding this
              ** SHARED lock. So do not actually release the OS lock.  */
              h = INVALID_HANDLE_VALUE;
              break;
            }
          }
          sqlite3_mutex_leave(pShmNode->mutex);
        }
      }

      if( h!=INVALID_HANDLE_VALUE ){
      rc = winHandleUnlock(p->hShm, ofst+WIN_SHM_BASE, n);
        rc = winHandleUnlock(h, ofst+WIN_SHM_BASE, n);
      }

      /* If successful, also clear the bits in sharedMask/exclMask */
      if( rc==SQLITE_OK ){
        p->exclMask = (p->exclMask & ~mask);
        p->sharedMask = (p->sharedMask & ~mask);
      }
    }else{
      int bExcl = ((flags & SQLITE_SHM_EXCLUSIVE) ? 1 : 0);
      DWORD nMs = winFileBusyTimeout(pDbFd);

      if( pShmNode->bUseSharedLockHandle ){
        winShm *pShm;
        h = pShmNode->hSharedShm;
        sqlite3_mutex_enter(pShmNode->mutex);
        for(pShm=pShmNode->pWinShmList; pShm; pShm=pShm->pWinShmNext){
          if( bExcl ){
            if( (pShm->sharedMask|pShm->exclMask) & mask ){
              rc = SQLITE_BUSY;
              h = INVALID_HANDLE_VALUE;
            }
          }else{
            if( pShm->sharedMask & mask ){
              h = INVALID_HANDLE_VALUE;
            }else if( pShm->exclMask & mask ){
              rc = SQLITE_BUSY;
              h = INVALID_HANDLE_VALUE;
            }
          }
        }
        sqlite3_mutex_leave(pShmNode->mutex);
      }

      if( h!=INVALID_HANDLE_VALUE ){
      rc = winHandleLockTimeout(p->hShm, ofst+WIN_SHM_BASE, n, bExcl, nMs);
        rc = winHandleLockTimeout(h, ofst+WIN_SHM_BASE, n, bExcl, nMs);
      }
      if( rc==SQLITE_OK ){
        if( bExcl ){
          p->exclMask = (p->exclMask | mask);
        }else{
          p->sharedMask = (p->sharedMask | mask);
        }
      }

    ** sqlite3_wal_checkpoint() call, but it happens very rarely.
    ** https://sqlite.org/forum/forumpost/fd0f19d229156939
    */
    sqlite3_exec(db, "PRAGMA table_list",0,0,0);
  }
  if( pPager->pWal ){
    rc = sqlite3WalCheckpoint(pPager->pWal, db, eMode,
        (eMode==SQLITE_CHECKPOINT_PASSIVE ? 0 : pPager->xBusyHandler),
        (eMode<=SQLITE_CHECKPOINT_PASSIVE ? 0 : pPager->xBusyHandler),
        pPager->pBusyHandlerArg,
        pPager->walSyncFlags, pPager->pageSize, (u8 *)pPager->pTmpSpace,
        pnLog, pnCkpt
    );
  }
  return rc;
}

  int (*xBusy2)(void*) = xBusy;   /* Busy handler for eMode2 */

  assert( pWal->ckptLock==0 );
  assert( pWal->writeLock==0 );

  /* EVIDENCE-OF: R-62920-47450 The busy-handler callback is never invoked
  ** in the SQLITE_CHECKPOINT_PASSIVE mode. */
  assert( SQLITE_CHECKPOINT_NOOP<SQLITE_CHECKPOINT_PASSIVE );
  assert( eMode!=SQLITE_CHECKPOINT_PASSIVE || xBusy==0 );
  assert( eMode>SQLITE_CHECKPOINT_PASSIVE || xBusy==0 );

  if( pWal->readOnly ) return SQLITE_READONLY;
  WALTRACE(("WAL%p: checkpoint begins\n", pWal));

  /* Enable blocking locks, if possible. */
  sqlite3WalDb(pWal, db);
  if( xBusy2 ) (void)walEnableBlocking(pWal);

  /* IMPLEMENTATION-OF: R-62028-47212 All calls obtain an exclusive
  ** "checkpoint" lock on the database file.
  ** EVIDENCE-OF: R-10421-19736 If any other process is running a
  ** checkpoint operation at the same time, the lock cannot be obtained and
  ** SQLITE_BUSY is returned.
  ** EVIDENCE-OF: R-53820-33897 Even if there is a busy-handler configured,
  ** it will not be invoked in this case.
  */
  if( eMode!=SQLITE_CHECKPOINT_NOOP ){
  rc = walLockExclusive(pWal, WAL_CKPT_LOCK, 1);
  testcase( rc==SQLITE_BUSY );
  testcase( rc!=SQLITE_OK && xBusy2!=0 );
  if( rc==SQLITE_OK ){
    pWal->ckptLock = 1;
    rc = walLockExclusive(pWal, WAL_CKPT_LOCK, 1);
    testcase( rc==SQLITE_BUSY );
    testcase( rc!=SQLITE_OK && xBusy2!=0 );
    if( rc==SQLITE_OK ){
      pWal->ckptLock = 1;

    /* IMPLEMENTATION-OF: R-59782-36818 The SQLITE_CHECKPOINT_FULL, RESTART and
    ** TRUNCATE modes also obtain the exclusive "writer" lock on the database
    ** file.
    **
    ** EVIDENCE-OF: R-60642-04082 If the writer lock cannot be obtained
    ** immediately, and a busy-handler is configured, it is invoked and the
    ** writer lock retried until either the busy-handler returns 0 or the
    ** lock is successfully obtained.
    */
    if( eMode!=SQLITE_CHECKPOINT_PASSIVE ){
      rc = walBusyLock(pWal, xBusy2, pBusyArg, WAL_WRITE_LOCK, 1);
      if( rc==SQLITE_OK ){
        pWal->writeLock = 1;
      }else if( rc==SQLITE_BUSY ){
        eMode2 = SQLITE_CHECKPOINT_PASSIVE;
        xBusy2 = 0;
        rc = SQLITE_OK;
      }
    }
      /* IMPLEMENTATION-OF: R-59782-36818 The SQLITE_CHECKPOINT_FULL, RESTART
      ** and TRUNCATE modes also obtain the exclusive "writer" lock on the
      ** database file.
      **
      ** EVIDENCE-OF: R-60642-04082 If the writer lock cannot be obtained
      ** immediately, and a busy-handler is configured, it is invoked and the
      ** writer lock retried until either the busy-handler returns 0 or the
      ** lock is successfully obtained.
      */
      if( eMode!=SQLITE_CHECKPOINT_PASSIVE ){
        rc = walBusyLock(pWal, xBusy2, pBusyArg, WAL_WRITE_LOCK, 1);
        if( rc==SQLITE_OK ){
          pWal->writeLock = 1;
        }else if( rc==SQLITE_BUSY ){
          eMode2 = SQLITE_CHECKPOINT_PASSIVE;
          xBusy2 = 0;
          rc = SQLITE_OK;
        }
      }
    }
  }else{
    rc = SQLITE_OK;
  }


  /* Read the wal-index header. */
  SEH_TRY {
    if( rc==SQLITE_OK ){
      /* For a passive checkpoint, do not re-enable blocking locks after
      ** reading the wal-index header. A passive checkpoint should not block
      ** or invoke the busy handler. The only lock such a checkpoint may
      ** attempt to obtain is a lock on a read-slot, and it should give up
      ** immediately and do a partial checkpoint if it cannot obtain it. */
      walDisableBlocking(pWal);
      rc = walIndexReadHdr(pWal, &isChanged);
      if( eMode2!=SQLITE_CHECKPOINT_PASSIVE ) (void)walEnableBlocking(pWal);
      if( eMode2>SQLITE_CHECKPOINT_PASSIVE ) (void)walEnableBlocking(pWal);
      if( isChanged && pWal->pDbFd->pMethods->iVersion>=3 ){
        sqlite3OsUnfetch(pWal->pDbFd, 0, 0);
      }
    }

    /* Copy data from the log to the database file. */
    if( rc==SQLITE_OK ){
      if( pWal->hdr.mxFrame && walPagesize(pWal)!=nBuf ){
        rc = SQLITE_CORRUPT_BKPT;
      }else{
      }else if( eMode2!=SQLITE_CHECKPOINT_NOOP ){
        rc = walCheckpoint(pWal, db, eMode2, xBusy2, pBusyArg, sync_flags,zBuf);
      }

      /* If no error occurred, set the output variables. */
      if( rc==SQLITE_OK || rc==SQLITE_BUSY ){
        if( pnLog ) *pnLog = (int)pWal->hdr.mxFrame;
        SEH_INJECT_FAULT;

       || (pCsr->nField==nRealCol+1 && op==SQLITE_DELETE && iReg==-1)
  );

  preupdate.v = v;
  preupdate.pCsr = pCsr;
  preupdate.op = op;
  preupdate.iNewReg = iReg;
  preupdate.pKeyinfo = (KeyInfo*)&preupdate.keyinfoSpace;
  preupdate.pKeyinfo = &preupdate.uKey.sKey;
  preupdate.pKeyinfo->db = db;
  preupdate.pKeyinfo->enc = ENC(db);
  preupdate.pKeyinfo->nKeyField = pTab->nCol;
  preupdate.pKeyinfo->aSortFlags = 0; /* Indicate .aColl, .nAllField uninit */
  preupdate.iKey1 = iKey1;
  preupdate.iKey2 = iKey2;
  preupdate.pTab = pTab;

  assert( p->readOnly==0 );
  aRes[0] = 0;
  aRes[1] = aRes[2] = -1;
  assert( pOp->p2==SQLITE_CHECKPOINT_PASSIVE
       || pOp->p2==SQLITE_CHECKPOINT_FULL
       || pOp->p2==SQLITE_CHECKPOINT_RESTART
       || pOp->p2==SQLITE_CHECKPOINT_TRUNCATE
       || pOp->p2==SQLITE_CHECKPOINT_NOOP
  );
  rc = sqlite3Checkpoint(db, pOp->p1, pOp->p2, &aRes[1], &aRes[2]);
  if( rc ){
    if( rc!=SQLITE_BUSY ) goto abort_due_to_error;
    rc = SQLITE_OK;
    aRes[0] = 1;
  }

  int type,        /* NC_IsCheck, NC_PartIdx, NC_IdxExpr, NC_GenCol, or 0 */
  Expr *pExpr,     /* Expression to resolve.  May be NULL. */
  ExprList *pList  /* Expression list to resolve.  May be NULL. */
){
  SrcList *pSrc;                  /* Fake SrcList for pParse->pNewTable */
  NameContext sNC;                /* Name context for pParse->pNewTable */
  int rc;
  union {
    SrcList sSrc;
  u8 srcSpace[SZ_SRCLIST_1];     /* Memory space for the fake SrcList */
    u8 srcSpace[SZ_SRCLIST_1];     /* Memory space for the fake SrcList */
  } uSrc;

  assert( type==0 || pTab!=0 );
  assert( type==NC_IsCheck || type==NC_PartIdx || type==NC_IdxExpr
          || type==NC_GenCol || pTab==0 );
  memset(&sNC, 0, sizeof(sNC));
  memset(&uSrc, 0, sizeof(uSrc));
  pSrc = (SrcList*)srcSpace;
  pSrc = &uSrc.sSrc;
  memset(pSrc, 0, SZ_SRCLIST_1);
  if( pTab ){
    pSrc->nSrc = 1;
    pSrc->a[0].zName = pTab->zName;
    pSrc->a[0].pSTab = pTab;
    pSrc->a[0].iCursor = -1;
    if( pTab->pSchema!=pParse->db->aDb[1].pSchema ){
      /* Cause EP_FromDDL to be set on TK_FUNCTION nodes of non-TEMP

    sqlite3ParserAddCleanup(pParse, sqlite3ExprListDeleteGeneric, pOrderBy);
    return;
  }
  if( IsWindowFunc(pExpr) ){
    sqlite3ExprOrderByAggregateError(pParse, pExpr);
    sqlite3ExprListDelete(db, pOrderBy);
    return;
  }
  if( pOrderBy->nExpr>db->aLimit[SQLITE_LIMIT_COLUMN] ){
    sqlite3ErrorMsg(pParse, "too many terms in ORDER BY clause");
    sqlite3ExprListDelete(db, pOrderBy);
    return;
  }

  pOB = sqlite3ExprAlloc(db, TK_ORDER, 0, 0);
  if( pOB==0 ){
    sqlite3ExprListDelete(db, pOrderBy);
    return;
  }

  Expr *pExpr,          /* The IN expression */
  int destIfFalse,      /* Jump here if LHS is not contained in the RHS */
  int destIfNull        /* Jump here if the results are unknown due to NULLs */
){
  int rRhsHasNull = 0;  /* Register that is true if RHS contains NULL values */
  int eType;            /* Type of the RHS */
  int rLhs;             /* Register(s) holding the LHS values */
  int rLhsOrig;         /* LHS values prior to reordering by aiMap[] */
  Vdbe *v;              /* Statement under construction */
  int *aiMap = 0;       /* Map from vector field to index column */
  char *zAff = 0;       /* Affinity string for comparisons */
  int nVector;          /* Size of vectors for this IN operator */
  int iDummy;           /* Dummy parameter to exprCodeVector() */
  Expr *pLeft;          /* The LHS of the IN operator */
  int i;                /* loop counter */

  ** the field order that matches the RHS index.
  **
  ** Avoid factoring the LHS of the IN(...) expression out of the loop,
  ** even if it is constant, as OP_Affinity may be used on the register
  ** by code generated below.  */
  assert( pParse->okConstFactor==okConstFactor );
  pParse->okConstFactor = 0;
  rLhsOrig = exprCodeVector(pParse, pLeft, &iDummy);
  rLhs = exprCodeVector(pParse, pLeft, &iDummy);
  pParse->okConstFactor = okConstFactor;
  for(i=0; i<nVector && aiMap[i]==i; i++){} /* Are LHS fields reordered? */
  if( i==nVector ){
    /* LHS fields are not reordered */
    rLhs = rLhsOrig;
  }else{
    /* Need to reorder the LHS fields according to aiMap */
    rLhs = sqlite3GetTempRange(pParse, nVector);
    for(i=0; i<nVector; i++){
      sqlite3VdbeAddOp3(v, OP_Copy, rLhsOrig+i, rLhs+aiMap[i], 0);
    }
  }

  /* If sqlite3FindInIndex() did not find or create an index that is
  ** suitable for evaluating the IN operator, then evaluate using a
  ** sequence of comparisons.
  **
  ** This is step (1) in the in-operator.md optimized algorithm.
  */
  if( eType==IN_INDEX_NOOP ){
    ExprList *pList;
    CollSeq *pColl;
    int labelOk = sqlite3VdbeMakeLabel(pParse);
    int r2, regToFree;
    int regCkNull = 0;
    int ii;
    assert( nVector==1 );
    assert( ExprUseXList(pExpr) );
    pList = pExpr->x.pList;
    pColl = sqlite3ExprCollSeq(pParse, pExpr->pLeft);
    if( destIfNull!=destIfFalse ){
      regCkNull = sqlite3GetTempReg(pParse);
      sqlite3VdbeAddOp3(v, OP_BitAnd, rLhs, rLhs, regCkNull);
    }

      sqlite3VdbeAddOp2(v, OP_IsNull, regCkNull, destIfNull); VdbeCoverage(v);
      sqlite3VdbeGoto(v, destIfFalse);
    }
    sqlite3VdbeResolveLabel(v, labelOk);
    sqlite3ReleaseTempReg(pParse, regCkNull);
    goto sqlite3ExprCodeIN_finished;
  }

  if( eType!=IN_INDEX_ROWID ){
    /* If this IN operator will use an index, then the order of columns in the
    ** vector might be different from the order in the index.  In that case,
    ** we need to reorder the LHS values to be in index order.  Run Affinity
    ** before reordering the columns, so that the affinity is correct.
    */
    sqlite3VdbeAddOp4(v, OP_Affinity, rLhs, nVector, 0, zAff, nVector);
    for(i=0; i<nVector && aiMap[i]==i; i++){} /* Are LHS fields reordered? */
    if( i!=nVector ){
      /* Need to reorder the LHS fields according to aiMap */
      int rLhsOrig = rLhs;
      rLhs = sqlite3GetTempRange(pParse, nVector);
      for(i=0; i<nVector; i++){
        sqlite3VdbeAddOp3(v, OP_Copy, rLhsOrig+i, rLhs+aiMap[i], 0);
      }
      sqlite3ReleaseTempReg(pParse, rLhsOrig);
    }
  }


  /* Step 2: Check to see if the LHS contains any NULL columns.  If the
  ** LHS does contain NULLs then the result must be either FALSE or NULL.
  ** We will then skip the binary search of the RHS.
  */
  if( destIfNull==destIfFalse ){
    destStep2 = destIfFalse;

  ** of the RHS using the LHS as a probe.  If found, the result is
  ** true.
  */
  if( eType==IN_INDEX_ROWID ){
    /* In this case, the RHS is the ROWID of table b-tree and so we also
    ** know that the RHS is non-NULL.  Hence, we combine steps 3 and 4
    ** into a single opcode. */
    assert( nVector==1 );
    sqlite3VdbeAddOp3(v, OP_SeekRowid, iTab, destIfFalse, rLhs);
    VdbeCoverage(v);
    addrTruthOp = sqlite3VdbeAddOp0(v, OP_Goto);  /* Return True */
  }else{
    sqlite3VdbeAddOp4(v, OP_Affinity, rLhs, nVector, 0, zAff, nVector);
    if( destIfFalse==destIfNull ){
      /* Combine Step 3 and Step 5 into a single opcode */
      if( ExprHasProperty(pExpr, EP_Subrtn) ){
        const VdbeOp *pOp = sqlite3VdbeGetOp(v, pExpr->y.sub.iAddr);
        assert( pOp->opcode==OP_Once || pParse->nErr );
        if( pOp->opcode==OP_Once && pOp->p3>0 ){  /* tag-202407032019 */
          assert( OptimizationEnabled(pParse->db, SQLITE_BloomFilter) );

    sqlite3VdbeAddOp2(v, OP_Goto, 0, destIfFalse);
  }

  /* Jumps here in order to return true. */
  sqlite3VdbeJumpHere(v, addrTruthOp);

sqlite3ExprCodeIN_finished:
  if( rLhs!=rLhsOrig ) sqlite3ReleaseTempReg(pParse, rLhs);
  VdbeComment((v, "end IN expr"));
sqlite3ExprCodeIN_oom_error:
  sqlite3DbFree(pParse->db, aiMap);
  sqlite3DbFree(pParse->db, zAff);
}
#endif /* SQLITE_OMIT_SUBQUERY */

** find the (first) offset of that column in index pIdx.  Or return -1
** if column iCol is not used in index pIdx.
*/
SQLITE_PRIVATE int sqlite3TableColumnToIndex(Index *pIdx, int iCol){
  int i;
  i16 iCol16;
  assert( iCol>=(-1) && iCol<=SQLITE_MAX_COLUMN );
  assert( pIdx->nColumn<=SQLITE_MAX_COLUMN+1 );
  assert( pIdx->nColumn<=SQLITE_MAX_COLUMN*2 );
  iCol16 = iCol;
  for(i=0; i<pIdx->nColumn; i++){
    if( iCol16==pIdx->aiColumn[i] ){
      return i;
    }
  }
  return -1;

      pKey->aColl[i] = zColl==sqlite3StrBINARY ? 0 :
                        sqlite3LocateCollSeq(pParse, zColl);
      pKey->aSortFlags[i] = pIdx->aSortOrder[i];
      assert( 0==(pKey->aSortFlags[i] & KEYINFO_ORDER_BIGNULL) );
    }
    if( pParse->nErr ){
      assert( pParse->rc==SQLITE_ERROR_MISSING_COLLSEQ );
      if( pIdx->bNoQuery==0 ){
      if( pIdx->bNoQuery==0
       && sqlite3HashFind(&pIdx->pSchema->idxHash, pIdx->zName)
      ){
        /* Deactivate the index because it contains an unknown collating
        ** sequence.  The only way to reactive the index is to reload the
        ** schema.  Adding the missing collating sequence later does not
        ** reactive the index.  The application had the chance to register
        ** the missing index using the collation-needed callback.  For
        ** simplicity, SQLite will not give the application a second chance.
        */
        **
        ** Except, do not do this if the index is not in the schema hash
        ** table. In this case the index is currently being constructed
        ** by a CREATE INDEX statement, and retrying will not help.  */
        pIdx->bNoQuery = 1;
        pParse->rc = SQLITE_ERROR_RETRY;
      }
      sqlite3KeyInfoUnref(pKey);
      pKey = 0;
    }
  }

    if( zRight ){
      if( sqlite3StrICmp(zRight, "full")==0 ){
        eMode = SQLITE_CHECKPOINT_FULL;
      }else if( sqlite3StrICmp(zRight, "restart")==0 ){
        eMode = SQLITE_CHECKPOINT_RESTART;
      }else if( sqlite3StrICmp(zRight, "truncate")==0 ){
        eMode = SQLITE_CHECKPOINT_TRUNCATE;
      }else if( sqlite3StrICmp(zRight, "noop")==0 ){
        eMode = SQLITE_CHECKPOINT_NOOP;
      }
    }
    pParse->nMem = 3;
    sqlite3VdbeAddOp3(v, OP_Checkpoint, iBt, eMode, 1);
    sqlite3VdbeAddOp2(v, OP_ResultRow, 1, 3);
  }
  break;

  do{
    /* Make multiple attempts to compile the SQL, until it either succeeds
    ** or encounters a permanent error.  A schema problem after one schema
    ** reset is considered a permanent error. */
    rc = sqlite3Prepare(db, zSql, nBytes, prepFlags, pOld, ppStmt, pzTail);
    assert( rc==SQLITE_OK || *ppStmt==0 );
    if( rc==SQLITE_OK || db->mallocFailed ) break;
    cnt++;
  }while( (rc==SQLITE_ERROR_RETRY && (cnt++)<SQLITE_MAX_PREPARE_RETRY)
       || (rc==SQLITE_SCHEMA && (sqlite3ResetOneSchema(db,-1), cnt++)==0) );
  }while( (rc==SQLITE_ERROR_RETRY && ALWAYS(cnt<=SQLITE_MAX_PREPARE_RETRY))
       || (rc==SQLITE_SCHEMA && (sqlite3ResetOneSchema(db,-1), cnt)==1) );
  sqlite3BtreeLeaveAll(db);
  assert( rc!=SQLITE_ERROR_RETRY );
  rc = sqlite3ApiExit(db, rc);
  assert( (rc&db->errMask)==rc );
  db->busyHandler.nBusy = 0;
  sqlite3_mutex_leave(db->mutex);
  assert( rc==SQLITE_OK || (*ppStmt)==0 );
  return rc;
}

SQLITE_PRIVATE void sqlite3SetJoinExpr(Expr *p, int iTable, u32 joinFlag){
  assert( joinFlag==EP_OuterON || joinFlag==EP_InnerON );
  while( p ){
    ExprSetProperty(p, joinFlag);
    assert( !ExprHasProperty(p, EP_TokenOnly|EP_Reduced) );
    ExprSetVVAProperty(p, EP_NoReduce);
    p->w.iJoin = iTable;
    if( p->op==TK_FUNCTION ){
      assert( ExprUseXList(p) );
    if( ExprUseXList(p) ){
      if( p->x.pList ){
        int i;
        for(i=0; i<p->x.pList->nExpr; i++){
          sqlite3SetJoinExpr(p->x.pList->a[i].pExpr, iTable, joinFlag);
        }
      }
    }

    ** an AND operator.
    */
    else if( pRight->u3.pOn ){
      sqlite3SetJoinExpr(pRight->u3.pOn, pRight->iCursor, joinType);
      p->pWhere = sqlite3ExprAnd(pParse, p->pWhere, pRight->u3.pOn);
      pRight->u3.pOn = 0;
      pRight->fg.isOn = 1;
      p->selFlags |= SF_OnToWhere;
    }
  }
  return 0;
}

/*
** An instance of this object holds information (beyond pParse and pSelect)

/*
** Allocate a KeyInfo object sufficient for an index of N key columns and
** X extra columns.
*/
SQLITE_PRIVATE KeyInfo *sqlite3KeyInfoAlloc(sqlite3 *db, int N, int X){
  int nExtra = (N+X)*(sizeof(CollSeq*)+1);
  KeyInfo *p;
  assert( X>=0 );
  if( NEVER(N+X>0xffff) ) return (KeyInfo*)sqlite3OomFault(db);
  KeyInfo *p = sqlite3DbMallocRawNN(db, SZ_KEYINFO(0) + nExtra);
  p = sqlite3DbMallocRawNN(db, SZ_KEYINFO(0) + nExtra);
  if( p ){
    p->aSortFlags = (u8*)&p->aColl[N+X];
    p->nKeyField = (u16)N;
    p->nAllField = (u16)(N+X);
    p->enc = ENC(db);
    p->db = db;
    p->nRef = 1;

**
** All references to columns in table iTable are to be replaced by corresponding
** expressions in pEList.
**
** ## About "isOuterJoin":
**
** The isOuterJoin column indicates that the replacement will occur into a
** position in the parent that NULL-able due to an OUTER JOIN.  Either the
** position in the parent that is NULL-able due to an OUTER JOIN.  Either the
** target slot in the parent is the right operand of a LEFT JOIN, or one of
** the left operands of a RIGHT JOIN.  In either case, we need to potentially
** bypass the substituted expression with OP_IfNullRow.
**
** Suppose the original expression is an integer constant. Even though the table
** has the nullRow flag set, because the expression is an integer constant,
** it will not be NULLed out.  So instead, we insert an OP_IfNullRow opcode

  ** will scan expressions looking for iParent references and replace
  ** those references with expressions that resolve to the subquery FROM
  ** elements we are now copying in.
  */
  pSub = pSub1;
  for(pParent=p; pParent; pParent=pParent->pPrior, pSub=pSub->pPrior){
    int nSubSrc;
    u8 jointype = 0;
    u8 jointype = pSubitem->fg.jointype;
    u8 ltorj = pSrc->a[iFrom].fg.jointype & JT_LTORJ;
    assert( pSub!=0 );
    pSubSrc = pSub->pSrc;     /* FROM clause of subquery */
    nSubSrc = pSubSrc->nSrc;  /* Number of terms in subquery FROM clause */
    pSrc = pParent->pSrc;     /* FROM clause of the outer query */

    if( pParent==p ){
      jointype = pSubitem->fg.jointype;     /* First time through the loop */
    }

    /* The subquery uses a single slot of the FROM clause of the outer
    ** query.  If the subquery has more than one element in its FROM clause,
    ** then expand the outer query to make space for it to hold all elements
    ** of the subquery.
    **
    ** Example:
    **
    **    SELECT * FROM tabA, (SELECT * FROM sub1, sub2), tabB;
    **
    ** The outer query has 3 slots in its FROM clause.  One slot of the
    ** outer query (the middle slot) is used by the subquery.  The next
    ** block of code will expand the outer query FROM clause to 4 slots.
    ** The middle slot is expanded to two slots in order to make space
    ** for the two elements in the FROM clause of the subquery.
    */
    if( nSubSrc>1 ){
      pSrc = sqlite3SrcListEnlarge(pParse, pSrc, nSubSrc-1,iFrom+1);
      if( pSrc==0 ) break;
      pParent->pSrc = pSrc;
      pSubitem = &pSrc->a[iFrom];
    }

    /* Transfer the FROM clause terms from the subquery into the
    ** outer query.
    */
    iNewParent = pSubSrc->a[0].iCursor;
    for(i=0; i<nSubSrc; i++){
      SrcItem *pItem = &pSrc->a[i+iFrom];
      assert( pItem->fg.isTabFunc==0 );
      assert( pItem->fg.isSubquery
           || pItem->fg.fixedSchema
           || pItem->u4.zDatabase==0 );
      if( pItem->fg.isUsing ) sqlite3IdListDelete(db, pItem->u3.pUsing);
      *pItem = pSubSrc->a[i];
      pItem->fg.jointype |= ltorj;
      pItem->fg.jointype |= (jointype & JT_LTORJ);
      memset(&pSubSrc->a[i], 0, sizeof(pSubSrc->a[i]));
    }
    pSrc->a[iFrom].fg.jointype &= JT_LTORJ;
    pSrc->a[iFrom].fg.jointype |= jointype | ltorj;
    pSubitem->fg.jointype |= jointype;

    /* Now begin substituting subquery result set expressions for
    ** references to the iParent in the outer query.
    **
    ** Example:
    **
    **   SELECT a+5, b*10 FROM (SELECT x*3 AS a, y+10 AS b FROM t1) WHERE a>b;

        }
#endif
        existsToJoin(pParse, p, pSubWhere);
      }
    }
  }
}

/*
** Type used for Walker callbacks by selectCheckOnClauses().
*/
typedef struct CheckOnCtx CheckOnCtx;
struct CheckOnCtx {
  SrcList *pSrc;                  /* SrcList for this context */
  int iJoin;                      /* Cursor numbers must be =< than this */
  CheckOnCtx *pParent;            /* Parent context */
};

/*
** True if the SrcList passed as the only argument contains at least
** one RIGHT or FULL JOIN. False otherwise.
*/
#define hasRightJoin(pSrc) (((pSrc)->a[0].fg.jointype & JT_LTORJ)!=0)

/*
** The xExpr callback for the search of invalid ON clause terms.
*/
static int selectCheckOnClausesExpr(Walker *pWalker, Expr *pExpr){
  CheckOnCtx *pCtx = pWalker->u.pCheckOnCtx;

  /* Check if pExpr is root or near-root of an ON clause constraint that needs
  ** to be checked to ensure that it does not refer to tables in its FROM
  ** clause to the right of itself. i.e. it is either:
  **
  **   + an ON clause on an OUTER join, or
  **   + an ON clause on an INNER join within a FROM that features at
  **     least one RIGHT or FULL join.
  */
  if( (ExprHasProperty(pExpr, EP_OuterON))
   || (ExprHasProperty(pExpr, EP_InnerON) && hasRightJoin(pCtx->pSrc))
  ){
    /* If CheckOnCtx.iJoin is already set, then fall through and process
    ** this expression node as normal. Or, if CheckOnCtx.iJoin is still 0,
    ** set it to the cursor number of the RHS of the join to which this
    ** ON expression was attached and then iterate through the entire
    ** expression.  */
    assert( pCtx->iJoin==0 || pCtx->iJoin==pExpr->w.iJoin );
    if( pCtx->iJoin==0 ){
      pCtx->iJoin = pExpr->w.iJoin;
      sqlite3WalkExprNN(pWalker, pExpr);
      pCtx->iJoin = 0;
      return WRC_Prune;
    }
  }

  if( pExpr->op==TK_COLUMN ){
    /* A column expression. Find the SrcList (if any) to which it refers.
    ** Then, if CheckOnCtx.iJoin indicates that this expression is part of an
    ** ON clause from that SrcList (i.e. if iJoin is non-zero), check that it
    ** does not refer to a table to the right of CheckOnCtx.iJoin. */
    do {
      SrcList *pSrc = pCtx->pSrc;
      int iTab = pExpr->iTable;
      if( iTab>=pSrc->a[0].iCursor && iTab<=pSrc->a[pSrc->nSrc-1].iCursor ){
        if( pCtx->iJoin && iTab>pCtx->iJoin ){
          sqlite3ErrorMsg(pWalker->pParse,
              "ON clause references tables to its right");
          return WRC_Abort;
        }
        break;
      }
      pCtx = pCtx->pParent;
    }while( pCtx );
  }
  return WRC_Continue;
}

/*
** The xSelect callback for the search of invalid ON clause terms.
*/
static int selectCheckOnClausesSelect(Walker *pWalker, Select *pSelect){
  CheckOnCtx *pCtx = pWalker->u.pCheckOnCtx;
  if( pSelect->pSrc==pCtx->pSrc || pSelect->pSrc->nSrc==0 ){
    return WRC_Continue;
  }else{
    CheckOnCtx sCtx;
    memset(&sCtx, 0, sizeof(sCtx));
    sCtx.pSrc = pSelect->pSrc;
    sCtx.pParent = pCtx;
    pWalker->u.pCheckOnCtx = &sCtx;
    sqlite3WalkSelect(pWalker, pSelect);
    pWalker->u.pCheckOnCtx = pCtx;
    pSelect->selFlags &= ~SF_OnToWhere;
    return WRC_Prune;
  }
}

/*
** Check all ON clauses in pSelect to verify that they do not reference
** columns to the right.
*/
static void selectCheckOnClauses(Parse *pParse, Select *pSelect){
  Walker w;
  CheckOnCtx sCtx;
  assert( pSelect->selFlags & SF_OnToWhere );
  assert( pSelect->pSrc!=0 && pSelect->pSrc->nSrc>=2 );
  memset(&w, 0, sizeof(w));
  w.pParse = pParse;
  w.xExprCallback = selectCheckOnClausesExpr;
  w.xSelectCallback = selectCheckOnClausesSelect;
  w.u.pCheckOnCtx = &sCtx;
  memset(&sCtx, 0, sizeof(sCtx));
  sCtx.pSrc = pSelect->pSrc;
  sqlite3WalkExprNN(&w, pSelect->pWhere);
  pSelect->selFlags &= ~SF_OnToWhere;
}

/*
** Generate byte-code for the SELECT statement given in the p argument.
**
** The results are returned according to the SelectDest structure.
** See comments in sqliteInt.h for further information.
**

  assert( p->pEList!=0 );
#if TREETRACE_ENABLED
  if( sqlite3TreeTrace & 0x10 ){
    TREETRACE(0x10,pParse,p, ("after name resolution:\n"));
    sqlite3TreeViewSelect(0, p, 0);
  }
#endif

  /* If the SELECT statement contains ON clauses that were moved into
  ** the WHERE clause, go through and verify that none of the terms
  ** in the ON clauses reference tables to the right of the ON clause.
  ** Do this now, after name resolution, but before query flattening
  */
  if( p->selFlags & SF_OnToWhere ){
    selectCheckOnClauses(pParse, p);
    if( pParse->nErr ){
      goto select_end;
    }
  }

  /* If the SF_UFSrcCheck flag is set, then this function is being called
  ** as part of populating the temp table for an UPDATE...FROM statement.
  ** In this case, it is an error if the target object (pSrc->a[0]) name
  ** or alias is duplicated within FROM clause (pSrc->a[1..n]).
  **
  ** Postgres disallows this case too. The reason is that some other

){
  Vdbe *v = pParse->pVdbe;
  sqlite3 *db = pParse->db;
  ExprList *pNew;
  Returning *pReturning;
  Select sSelect;
  SrcList *pFrom;
  union {
    SrcList sSrc;
  u8 fromSpace[SZ_SRCLIST_1];
    u8 fromSpace[SZ_SRCLIST_1];
  } uSrc;

  assert( v!=0 );
  if( !pParse->bReturning ){
    /* This RETURNING trigger must be for a different statement as
    ** this statement lacks a RETURNING clause. */
    return;
  }
  assert( db->pParse==pParse );
  assert( !pParse->isCreate );
  pReturning = pParse->u1.d.pReturning;
  if( pTrigger != &(pReturning->retTrig) ){
    /* This RETURNING trigger is for a different statement */
    return;
  }
  memset(&sSelect, 0, sizeof(sSelect));
  memset(&uSrc, 0, sizeof(uSrc));
  pFrom = (SrcList*)fromSpace;
  pFrom = &uSrc.sSrc;
  memset(pFrom, 0, SZ_SRCLIST_1);
  sSelect.pEList = sqlite3ExprListDup(db, pReturning->pReturnEL, 0);
  sSelect.pSrc = pFrom;
  pFrom->nSrc = 1;
  pFrom->a[0].pSTab = pTab;
  pFrom->a[0].zName = pTab->zName; /* tag-20240424-1 */
  pFrom->a[0].iCursor = -1;
  sqlite3SelectPrep(pParse, &sSelect, 0);

  WhereRightJoin *pRJ = pLevel->pRJ;
  Expr *pSubWhere = 0;
  WhereClause *pWC = &pWInfo->sWC;
  WhereInfo *pSubWInfo;
  WhereLoop *pLoop = pLevel->pWLoop;
  SrcItem *pTabItem = &pWInfo->pTabList->a[pLevel->iFrom];
  SrcList *pFrom;
  union {
    SrcList sSrc;
  u8 fromSpace[SZ_SRCLIST_1];
    u8 fromSpace[SZ_SRCLIST_1];
  } uSrc;
  Bitmask mAll = 0;
  int k;

  ExplainQueryPlan((pParse, 1, "RIGHT-JOIN %s", pTabItem->pSTab->zName));
  sqlite3VdbeNoJumpsOutsideSubrtn(v, pRJ->addrSubrtn, pRJ->endSubrtn,
                                  pRJ->regReturn);
  for(k=0; k<iLevel; k++){

      }
      if( pTerm->prereqAll & ~mAll ) continue;
      if( ExprHasProperty(pTerm->pExpr, EP_OuterON|EP_InnerON) ) continue;
      pSubWhere = sqlite3ExprAnd(pParse, pSubWhere,
                                 sqlite3ExprDup(pParse->db, pTerm->pExpr, 0));
    }
  }
  pFrom = (SrcList*)fromSpace;
  pFrom = &uSrc.sSrc;
  pFrom->nSrc = 1;
  pFrom->nAlloc = 1;
  memcpy(&pFrom->a[0], pTabItem, sizeof(SrcItem));
  pFrom->a[0].fg.jointype = 0;
  assert( pParse->withinRJSubrtn < 100 );
  pParse->withinRJSubrtn++;
  pSubWInfo = sqlite3WhereBegin(pParse, pFrom, pSubWhere, 0, 0, 0,

  if( ExprHasProperty(pExpr, EP_OuterON|EP_InnerON) ){
    Bitmask x = sqlite3WhereGetMask(pMaskSet, pExpr->w.iJoin);
    if( ExprHasProperty(pExpr, EP_OuterON) ){
      prereqAll |= x;
      extraRight = x-1;  /* ON clause terms may not be used with an index
                         ** on left table of a LEFT JOIN.  Ticket #3015 */
      if( (prereqAll>>1)>=x ){
        sqlite3ErrorMsg(pParse, "ON clause references tables to its right");
        return;
      }
    }else if( (prereqAll>>1)>=x ){
      /* The ON clause of an INNER JOIN references a table to its right.
      ** Most other SQL database engines raise an error.  But SQLite versions
      ** 3.0 through 3.38 just put the ON clause constraint into the WHERE
      ** clause and carried on.   Beginning with 3.39, raise an error only
      ** if there is a RIGHT or FULL JOIN in the query.  This makes SQLite
      ** more like other systems, and also preserves legacy. */
      if( ALWAYS(pSrc->nSrc>0) && (pSrc->a[0].fg.jointype & JT_LTORJ)!=0 ){
        sqlite3ErrorMsg(pParse, "ON clause references tables to its right");
        return;
      }
      ExprClearProperty(pExpr, EP_InnerON);
    }
  }
  pTerm->prereqAll = prereqAll;
  pTerm->leftCursor = -1;
  pTerm->iParent = -1;
  pTerm->eOperator = 0;

  const char *zName = 0;
  int i, origRc = rc;
  for(i=0; i<2 && zName==0; i++, rc &= 0xff){
    switch( rc ){
      case SQLITE_OK:                 zName = "SQLITE_OK";                break;
      case SQLITE_ERROR:              zName = "SQLITE_ERROR";             break;
      case SQLITE_ERROR_SNAPSHOT:     zName = "SQLITE_ERROR_SNAPSHOT";    break;
      case SQLITE_ERROR_RETRY:        zName = "SQLITE_ERROR_RETRY";       break;
      case SQLITE_ERROR_MISSING_COLLSEQ:
                                zName = "SQLITE_ERROR_MISSING_COLLSEQ";   break;
      case SQLITE_INTERNAL:           zName = "SQLITE_INTERNAL";          break;
      case SQLITE_PERM:               zName = "SQLITE_PERM";              break;
      case SQLITE_ABORT:              zName = "SQLITE_ABORT";             break;
      case SQLITE_ABORT_ROLLBACK:     zName = "SQLITE_ABORT_ROLLBACK";    break;
      case SQLITE_BUSY:               zName = "SQLITE_BUSY";              break;
      case SQLITE_BUSY_RECOVERY:      zName = "SQLITE_BUSY_RECOVERY";     break;
      case SQLITE_BUSY_SNAPSHOT:      zName = "SQLITE_BUSY_SNAPSHOT";     break;

**
******************************************************************************
**
*/
#ifndef _FTSINT_H
#define _FTSINT_H

/*
** Activate assert() only if SQLITE_TEST is enabled.
*/
#if !defined(NDEBUG) && !defined(SQLITE_DEBUG)
# define NDEBUG 1
#endif

/* #include <assert.h> */
/* #include <stdlib.h> */
/* #include <stddef.h> */
/* #include <stdio.h> */
/* #include <string.h> */
/* #include <stdarg.h> */

#if !defined(NDEBUG) && !defined(SQLITE_DEBUG)
# define NDEBUG 1
#endif

/* FTS3/FTS4 require virtual tables */
#ifdef SQLITE_OMIT_VIRTUALTABLE
# undef SQLITE_ENABLE_FTS3
# undef SQLITE_ENABLE_FTS4
#endif

/*

typedef sqlite3_int64 i64;        /* 8-byte signed integer */

/*
** Macro used to suppress compiler warnings for unused parameters.
*/
#define UNUSED_PARAMETER(x) (void)(x)

/*
** Activate assert() only if SQLITE_TEST is enabled.
*/
#if !defined(NDEBUG) && !defined(SQLITE_DEBUG)
# define NDEBUG 1
#endif

/*
** The TESTONLY macro is used to enclose variable declarations or
** other bits of code that are needed to support the arguments
** within testcase() and assert() macros.
*/
#if defined(SQLITE_DEBUG) || defined(SQLITE_COVERAGE_TEST)
# define TESTONLY(X)  X

};

/*
** An object of this type contains the state required to create or append
** to an appendable b-tree segment.
*/
struct IncrmergeWriter {
  int nLeafEst;                   /* Space allocated for leaf blocks */
  int nWork;                      /* Number of leaf pages flushed */
  i64 nLeafEst;                   /* Space allocated for leaf blocks */
  i64 nWork;                      /* Number of leaf pages flushed */
  sqlite3_int64 iAbsLevel;        /* Absolute level of input segments */
  int iIdx;                       /* Index of *output* segment in iAbsLevel+1 */
  sqlite3_int64 iStart;           /* Block number of first allocated block */
  sqlite3_int64 iEnd;             /* Block number of last allocated block */
  sqlite3_int64 nLeafData;        /* Bytes of leaf page data so far */
  u8 bNoLeafData;                 /* If true, store 0 for segment size */
  NodeWriter aNodeWriter[FTS_MAX_APPENDABLE_HEIGHT];

  sqlite3_int64 iAbsLevel,        /* Absolute level of input segments */
  int iIdx,                       /* Index of new output segment */
  Fts3MultiSegReader *pCsr,       /* Cursor that data will be read from */
  IncrmergeWriter *pWriter        /* Populate this object */
){
  int rc;                         /* Return Code */
  int i;                          /* Iterator variable */
  int nLeafEst = 0;               /* Blocks allocated for leaf nodes */
  i64 nLeafEst = 0;               /* Blocks allocated for leaf nodes */
  sqlite3_stmt *pLeafEst = 0;     /* SQL used to determine nLeafEst */
  sqlite3_stmt *pFirstBlock = 0;  /* SQL used to determine first block */

  /* Calculate nLeafEst. */
  rc = fts3SqlStmt(p, SQL_MAX_LEAF_NODE_ESTIMATE, &pLeafEst, 0);
  if( rc==SQLITE_OK ){
    sqlite3_bind_int64(pLeafEst, 1, iAbsLevel);
    sqlite3_bind_int64(pLeafEst, 2, pCsr->nSegment);
    if( SQLITE_ROW==sqlite3_step(pLeafEst) ){
      nLeafEst = sqlite3_column_int(pLeafEst, 0);
      nLeafEst = sqlite3_column_int64(pLeafEst, 0);
    }
    rc = sqlite3_reset(pLeafEst);
  }
  if( rc!=SQLITE_OK ) return rc;

  /* Calculate the first block to use in the output segment */
  rc = fts3SqlStmt(p, SQL_NEXT_SEGMENTS_ID, &pFirstBlock, 0);

    && !defined(SQLITE_OMIT_VIRTUALTABLE)

typedef struct DbpageTable DbpageTable;
typedef struct DbpageCursor DbpageCursor;

struct DbpageCursor {
  sqlite3_vtab_cursor base;       /* Base class.  Must be first */
  int pgno;                       /* Current page number */
  Pgno pgno;                      /* Current page number */
  int mxPgno;                     /* Last page to visit on this scan */
  Pager *pPager;                  /* Pager being read/written */
  DbPage *pPage1;                 /* Page 1 of the database */
  int iDb;                        /* Index of database to analyze */
  int szPage;                     /* Size of each page in bytes */
};

  pCsr = (DbpageCursor *)sqlite3_malloc64(sizeof(DbpageCursor));
  if( pCsr==0 ){
    return SQLITE_NOMEM_BKPT;
  }else{
    memset(pCsr, 0, sizeof(DbpageCursor));
    pCsr->base.pVtab = pVTab;
    pCsr->pgno = -1;
    pCsr->pgno = 0;
  }

  *ppCursor = (sqlite3_vtab_cursor *)pCsr;
  return SQLITE_OK;
}

/*

  sqlite3_context *ctx,
  int i
){
  DbpageCursor *pCsr = (DbpageCursor *)pCursor;
  int rc = SQLITE_OK;
  switch( i ){
    case 0: {           /* pgno */
      sqlite3_result_int(ctx, pCsr->pgno);
      sqlite3_result_int64(ctx, (sqlite3_int64)pCsr->pgno);
      break;
    }
    case 1: {           /* data */
      DbPage *pDbPage = 0;
      if( pCsr->pgno==((PENDING_BYTE/pCsr->szPage)+1) ){
      if( pCsr->pgno==(Pgno)((PENDING_BYTE/pCsr->szPage)+1) ){
        /* The pending byte page. Assume it is zeroed out. Attempting to
        ** request this page from the page is an SQLITE_CORRUPT error. */
        sqlite3_result_zeroblob(ctx, pCsr->szPage);
      }else{
        rc = sqlite3PagerGet(pCsr->pPager, pCsr->pgno, (DbPage**)&pDbPage, 0);
        if( rc==SQLITE_OK ){
          sqlite3_result_blob(ctx, sqlite3PagerGetData(pDbPage), pCsr->szPage,

    goto update_fail;
  }
  if( argc==1 ){
    zErr = "cannot delete";
    goto update_fail;
  }
  if( sqlite3_value_type(argv[0])==SQLITE_NULL ){
    pgno = (Pgno)sqlite3_value_int(argv[2]);
    pgno = (Pgno)sqlite3_value_int64(argv[2]);
    isInsert = 1;
  }else{
    pgno = sqlite3_value_int(argv[0]);
    pgno = (Pgno)sqlite3_value_int64(argv[0]);
    if( (Pgno)sqlite3_value_int(argv[1])!=pgno ){
      zErr = "cannot insert";
      goto update_fail;
    }
    isInsert = 0;
  }
  if( sqlite3_value_type(argv[4])==SQLITE_NULL ){

  int eType,                      /* Either CHANGESET_DATA or CONFLICT */
  SessionApplyCtx *p,             /* changeset_apply() context */
  sqlite3_changeset_iter *pIter,  /* Changeset iterator */
  int(*xConflict)(void *, int, sqlite3_changeset_iter*),
  void *pCtx,                     /* First argument for conflict handler */
  int *pbReplace                  /* OUT: Set to true if PK row is found */
){
  int res = 0;                    /* Value returned by conflict handler */
  int res = SQLITE_CHANGESET_OMIT;/* Value returned by conflict handler */
  int rc;
  int nCol;
  int op;
  const char *zDummy;

  sqlite3changeset_op(pIter, &zDummy, &nCol, &op, 0);

  assert( eType==SQLITE_CHANGESET_CONFLICT || eType==SQLITE_CHANGESET_DATA );
  assert( SQLITE_CHANGESET_CONFLICT+1==SQLITE_CHANGESET_CONSTRAINT );
  assert( SQLITE_CHANGESET_DATA+1==SQLITE_CHANGESET_NOTFOUND );

  /* Bind the new.* PRIMARY KEY values to the SELECT statement. */
  if( pbReplace ){
    rc = sessionSeekToRow(pIter, p);
  }else{
    rc = SQLITE_OK;
  }

  if( rc==SQLITE_ROW ){
    /* There exists another row with the new.* primary key. */
    if( p->bIgnoreNoop
     && sqlite3_column_int(p->pSelect, sqlite3_column_count(p->pSelect)-1)
    if( 0==p->bIgnoreNoop
     || 0==sqlite3_column_int(p->pSelect, sqlite3_column_count(p->pSelect)-1)
    ){
      res = SQLITE_CHANGESET_OMIT;
    }else{
      pIter->pConflict = p->pSelect;
      res = xConflict(pCtx, eType, pIter);
      pIter->pConflict = 0;
    }
    rc = sqlite3_reset(p->pSelect);
  }else if( rc==SQLITE_OK ){
    if( p->bDeferConstraints && eType==SQLITE_CHANGESET_CONFLICT ){
      /* Instead of invoking the conflict handler, append the change blob
      ** to the SessionApplyCtx.constraints buffer. */
      u8 *aBlob = &pIter->in.aData[pIter->in.iCurrent];
      int nBlob = pIter->in.iNext - pIter->in.iCurrent;
      sessionAppendBlob(&p->constraints, aBlob, nBlob, &rc);
      return SQLITE_OK;
    }else{
    }else if( p->bIgnoreNoop==0 || op!=SQLITE_DELETE
           || eType==SQLITE_CHANGESET_CONFLICT
    ){
      /* No other row with the new.* primary key. */
      res = xConflict(pCtx, eType+1, pIter);
      if( res==SQLITE_CHANGESET_REPLACE ) rc = SQLITE_MISUSE;
    }
  }

  if( rc==SQLITE_OK ){

    if( rc==SQLITE_OK && sqlite3_bind_parameter_count(p->pDelete)>nCol ){
      rc = sqlite3_bind_int(p->pDelete, nCol+1, (pbRetry==0 || abPK));
    }
    if( rc!=SQLITE_OK ) return rc;

    sqlite3_step(p->pDelete);
    rc = sqlite3_reset(p->pDelete);
    if( rc==SQLITE_OK && sqlite3_changes(p->db)==0 && p->bIgnoreNoop==0 ){
    if( rc==SQLITE_OK && sqlite3_changes(p->db)==0 ){
      rc = sessionConflictHandler(
          SQLITE_CHANGESET_DATA, p, pIter, xConflict, pCtx, pbRetry
      );
    }else if( (rc&0xff)==SQLITE_CONSTRAINT ){
      rc = sessionConflictHandler(
          SQLITE_CHANGESET_CONFLICT, p, pIter, xConflict, pCtx, 0
      );

/*
** Constants for the largest and smallest possible 64-bit signed integers.
*/
# define LARGEST_INT64  (0xffffffff|(((i64)0x7fffffff)<<32))
# define SMALLEST_INT64 (((i64)-1) - LARGEST_INT64)

/* The uptr type is an unsigned integer large enough to hold a pointer
/*
** This macro is used in a single assert() within fts5 to check that an
** allocation is aligned to an 8-byte boundary. But it is a complicated
** macro to get right for multiple platforms without generating warnings.
** So instead of reproducing the entire definition from sqliteInt.h, we
** just do without this assert() for the rare non-amalgamation builds.
*/
#if defined(HAVE_STDINT_H)
  typedef uintptr_t uptr;
#elif SQLITE_PTRSIZE==4
  typedef u32 uptr;
#else
  typedef u64 uptr;
#endif

#ifdef SQLITE_4_BYTE_ALIGNED_MALLOC
# define EIGHT_BYTE_ALIGNMENT(X)   ((((uptr)(X) - (uptr)0)&3)==0)
#define EIGHT_BYTE_ALIGNMENT(x) 1
#else
# define EIGHT_BYTE_ALIGNMENT(X)   ((((uptr)(X) - (uptr)0)&7)==0)
#endif

/*
** Macros needed to provide flexible arrays in a portable way
*/
#ifndef offsetof
# define offsetof(ST,M) ((size_t)((char*)&((ST*)0)->M - (char*)0))
#endif

/*
** The %_data table is completely empty when this function is called. This
** function populates it with the initial structure objects for each index,
** and the initial version of the "averages" record (a zero-byte blob).
*/
static int sqlite3Fts5IndexReinit(Fts5Index *p){
  Fts5Structure *pTmp;
  union {
    Fts5Structure sFts;
  u8 tmpSpace[SZ_FTS5STRUCTURE(1)];
    u8 tmpSpace[SZ_FTS5STRUCTURE(1)];
  } uFts;
  fts5StructureInvalidate(p);
  fts5IndexDiscardData(p);
  pTmp = (Fts5Structure*)tmpSpace;
  pTmp = &uFts.sFts;
  memset(pTmp, 0, SZ_FTS5STRUCTURE(1));
  if( p->pConfig->bContentlessDelete ){
    pTmp->nOriginCntr = 1;
  }
  fts5DataWrite(p, FTS5_AVERAGES_ROWID, (const u8*)"", 0);
  fts5StructureWrite(p, pTmp);
  return fts5IndexReturn(p);

static void fts5SourceIdFunc(
  sqlite3_context *pCtx,          /* Function call context */
  int nArg,                       /* Number of args */
  sqlite3_value **apUnused        /* Function arguments */
){
  assert( nArg==0 );
  UNUSED_PARAM2(nArg, apUnused);
  sqlite3_result_text(pCtx, "fts5: 2025-07-30 16:17:14 cf7163f82ca380958a79350473b2c5a2cebda7496d6d575fa2835c362010fea1", -1, SQLITE_TRANSIENT);
  sqlite3_result_text(pCtx, "fts5: 2025-09-09 10:28:06 0f31711591c56f3896fb6f092752fb82c4ea646bf8e5838dfbe55302994ea091", -1, SQLITE_TRANSIENT);
}

/*
** Implementation of fts5_locale(LOCALE, TEXT) function.
**
** If parameter LOCALE is NULL, or a zero-length string, then a copy of
** TEXT is returned. Otherwise, both LOCALE and TEXT are interpreted as