text: /*
  ** 2011 March 18
  **
  ** The author disclaims copyright to this source code.  In place of
  ** a legal notice, here is a blessing:
  **
  **    May you do good and not evil.
  **    May you find forgiveness for yourself and forgive others.
  **    May you share freely, never taking more than you give.
  **
  *************************************************************************
  **
  ** This file contains a VFS "shim" - a layer that sits in between the
  ** pager and the real VFS.
  **
  ** This particular shim enforces a multiplex system on DB files.
  ** This shim shards/partitions a single DB file into smaller
  ** "chunks" such that the total DB file size may exceed the maximum
  ** file size of the underlying file system.
  **
  */
  
  #ifndef SQLITE_TEST_MULTIPLEX_H
  #define SQLITE_TEST_MULTIPLEX_H
  
  /*
  ** CAPI: File-control Operations Supported by Multiplex VFS
  **
  ** Values interpreted by the xFileControl method of a Multiplex VFS db file-handle.
  **
  ** MULTIPLEX_CTRL_ENABLE:
  **   This file control is used to enable or disable the multiplex
  **   shim.
  **
  ** MULTIPLEX_CTRL_SET_CHUNK_SIZE:
  **   This file control is used to set the maximum allowed chunk
  **   size for a multiplex file set.  The chunk size should be
  **   a multiple of SQLITE_MAX_PAGE_SIZE, and will be rounded up
  **   if not.
  **
  ** MULTIPLEX_CTRL_SET_MAX_CHUNKS:
  **   This file control is used to set the maximum number of chunks
  **   allowed to be used for a mutliplex file set.
  */
  #define MULTIPLEX_CTRL_ENABLE          214014
  #define MULTIPLEX_CTRL_SET_CHUNK_SIZE  214015
  #define MULTIPLEX_CTRL_SET_MAX_CHUNKS  214016
  
  #ifdef __cplusplus
  extern "C" {
  #endif
  
  /*
  ** CAPI: Initialize the multiplex VFS shim - sqlite3_multiplex_initialize()
  **
  ** Use the VFS named zOrigVfsName as the VFS that does the actual work.
  ** Use the default if zOrigVfsName==NULL.
  **
  ** The multiplex VFS shim is named "multiplex".  It will become the default
  ** VFS if makeDefault is non-zero.
  **
  ** An auto-extension is registered which will make the function
  ** multiplex_control() available to database connections.  This
  ** function gives access to the xFileControl interface of the
  ** multiplex VFS shim.
  **
  ** SELECT multiplex_control(<op>,<val>);
  **
  **   <op>=1 MULTIPLEX_CTRL_ENABLE
  **   <val>=0 disable
  **   <val>=1 enable
  **
  **   <op>=2 MULTIPLEX_CTRL_SET_CHUNK_SIZE
  **   <val> int, chunk size
  **
  **   <op>=3 MULTIPLEX_CTRL_SET_MAX_CHUNKS
  **   <val> int, max chunks
  **
  ** THIS ROUTINE IS NOT THREADSAFE.  Call this routine exactly once
  ** during start-up.
  */
  extern int sqlite3_multiplex_initialize(const char *zOrigVfsName, int makeDefault);
  
  /*
  ** CAPI: Shutdown the multiplex system - sqlite3_multiplex_shutdown()
  **
  ** All SQLite database connections must be closed before calling this
  ** routine.
  **
  ** THIS ROUTINE IS NOT THREADSAFE.  Call this routine exactly once while
  ** shutting down in order to free all remaining multiplex groups.
  */
  extern int sqlite3_multiplex_shutdown(int eForce);
  
  #ifdef __cplusplus
  }  /* End of the 'extern "C"' block */
  #endif
  
  #endif /* SQLITE_TEST_MULTIPLEX_H */
  