/*

** 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 */