/*
** 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 multiplex 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 */