| Index: third_party/sqlite/ext/async/sqlite3async.h
 | 
| ===================================================================
 | 
| --- third_party/sqlite/ext/async/sqlite3async.h	(revision 56608)
 | 
| +++ third_party/sqlite/ext/async/sqlite3async.h	(working copy)
 | 
| @@ -1,223 +0,0 @@
 | 
| -
 | 
| -#ifndef __SQLITEASYNC_H_
 | 
| -#define __SQLITEASYNC_H_ 1
 | 
| -
 | 
| -/*
 | 
| -** Make sure we can call this stuff from C++.
 | 
| -*/
 | 
| -#ifdef __cplusplus
 | 
| -extern "C" {
 | 
| -#endif
 | 
| -
 | 
| -#define SQLITEASYNC_VFSNAME "sqlite3async"
 | 
| -
 | 
| -/*
 | 
| -** THREAD SAFETY NOTES:
 | 
| -**
 | 
| -** Of the four API functions in this file, the following are not threadsafe:
 | 
| -**
 | 
| -**   sqlite3async_initialize()
 | 
| -**   sqlite3async_shutdown()
 | 
| -**
 | 
| -** Care must be taken that neither of these functions is called while 
 | 
| -** another thread may be calling either any sqlite3async_XXX() function
 | 
| -** or an sqlite3_XXX() API function related to a database handle that
 | 
| -** is using the asynchronous IO VFS.
 | 
| -**
 | 
| -** These functions:
 | 
| -**
 | 
| -**   sqlite3async_run()
 | 
| -**   sqlite3async_control()
 | 
| -**
 | 
| -** are threadsafe. It is quite safe to call either of these functions even
 | 
| -** if another thread may also be calling one of them or an sqlite3_XXX()
 | 
| -** function related to a database handle that uses the asynchronous IO VFS.
 | 
| -*/
 | 
| -
 | 
| -/*
 | 
| -** Initialize the asynchronous IO VFS and register it with SQLite using
 | 
| -** sqlite3_vfs_register(). If the asynchronous VFS is already initialized
 | 
| -** and registered, this function is a no-op. The asynchronous IO VFS
 | 
| -** is registered as "sqlite3async".
 | 
| -**
 | 
| -** The asynchronous IO VFS does not make operating system IO requests 
 | 
| -** directly. Instead, it uses an existing VFS implementation for all
 | 
| -** required file-system operations. If the first parameter to this function
 | 
| -** is NULL, then the current default VFS is used for IO. If it is not
 | 
| -** NULL, then it must be the name of an existing VFS. In other words, the
 | 
| -** first argument to this function is passed to sqlite3_vfs_find() to
 | 
| -** locate the VFS to use for all real IO operations. This VFS is known
 | 
| -** as the "parent VFS".
 | 
| -**
 | 
| -** If the second parameter to this function is non-zero, then the 
 | 
| -** asynchronous IO VFS is registered as the default VFS for all SQLite 
 | 
| -** database connections within the process. Otherwise, the asynchronous IO
 | 
| -** VFS is only used by connections opened using sqlite3_open_v2() that
 | 
| -** specifically request VFS "sqlite3async".
 | 
| -**
 | 
| -** If a parent VFS cannot be located, then SQLITE_ERROR is returned.
 | 
| -** In the unlikely event that operating system specific initialization
 | 
| -** fails (win32 systems create the required critical section and event 
 | 
| -** objects within this function), then SQLITE_ERROR is also returned.
 | 
| -** Finally, if the call to sqlite3_vfs_register() returns an error, then 
 | 
| -** the error code is returned to the user by this function. In all three
 | 
| -** of these cases, intialization has failed and the asynchronous IO VFS
 | 
| -** is not registered with SQLite.
 | 
| -**
 | 
| -** Otherwise, if no error occurs, SQLITE_OK is returned.
 | 
| -*/ 
 | 
| -int sqlite3async_initialize(const char *zParent, int isDefault);
 | 
| -
 | 
| -/*
 | 
| -** This function unregisters the asynchronous IO VFS using 
 | 
| -** sqlite3_vfs_unregister().
 | 
| -**
 | 
| -** On win32 platforms, this function also releases the small number of 
 | 
| -** critical section and event objects created by sqlite3async_initialize().
 | 
| -*/ 
 | 
| -void sqlite3async_shutdown();
 | 
| -
 | 
| -/*
 | 
| -** This function may only be called when the asynchronous IO VFS is 
 | 
| -** installed (after a call to sqlite3async_initialize()). It processes
 | 
| -** zero or more queued write operations before returning. It is expected
 | 
| -** (but not required) that this function will be called by a different 
 | 
| -** thread than those threads that use SQLite. The "background thread"
 | 
| -** that performs IO.
 | 
| -**
 | 
| -** How many queued write operations are performed before returning 
 | 
| -** depends on the global setting configured by passing the SQLITEASYNC_HALT
 | 
| -** verb to sqlite3async_control() (see below for details). By default
 | 
| -** this function never returns - it processes all pending operations and 
 | 
| -** then blocks waiting for new ones.
 | 
| -**
 | 
| -** If multiple simultaneous calls are made to sqlite3async_run() from two
 | 
| -** or more threads, then the calls are serialized internally.
 | 
| -*/
 | 
| -void sqlite3async_run();
 | 
| -
 | 
| -/*
 | 
| -** This function may only be called when the asynchronous IO VFS is 
 | 
| -** installed (after a call to sqlite3async_initialize()). It is used 
 | 
| -** to query or configure various parameters that affect the operation 
 | 
| -** of the asynchronous IO VFS. At present there are three parameters 
 | 
| -** supported:
 | 
| -**
 | 
| -**   * The "halt" parameter, which configures the circumstances under
 | 
| -**     which the sqlite3async_run() parameter is configured.
 | 
| -**
 | 
| -**   * The "delay" parameter. Setting the delay parameter to a non-zero
 | 
| -**     value causes the sqlite3async_run() function to sleep for the
 | 
| -**     configured number of milliseconds between each queued write 
 | 
| -**     operation.
 | 
| -**
 | 
| -**   * The "lockfiles" parameter. This parameter determines whether or 
 | 
| -**     not the asynchronous IO VFS locks the database files it operates
 | 
| -**     on. Disabling file locking can improve throughput.
 | 
| -**
 | 
| -** This function is always passed two arguments. When setting the value
 | 
| -** of a parameter, the first argument must be one of SQLITEASYNC_HALT,
 | 
| -** SQLITEASYNC_DELAY or SQLITEASYNC_LOCKFILES. The second argument must
 | 
| -** be passed the new value for the parameter as type "int".
 | 
| -**
 | 
| -** When querying the current value of a paramter, the first argument must
 | 
| -** be one of SQLITEASYNC_GET_HALT, GET_DELAY or GET_LOCKFILES. The second 
 | 
| -** argument to this function must be of type (int *). The current value
 | 
| -** of the queried parameter is copied to the memory pointed to by the
 | 
| -** second argument. For example:
 | 
| -**
 | 
| -**   int eCurrentHalt;
 | 
| -**   int eNewHalt = SQLITEASYNC_HALT_IDLE;
 | 
| -**
 | 
| -**   sqlite3async_control(SQLITEASYNC_HALT, eNewHalt);
 | 
| -**   sqlite3async_control(SQLITEASYNC_GET_HALT, &eCurrentHalt);
 | 
| -**   assert( eNewHalt==eCurrentHalt );
 | 
| -**
 | 
| -** See below for more detail on each configuration parameter.
 | 
| -**
 | 
| -** SQLITEASYNC_HALT:
 | 
| -**
 | 
| -**   This is used to set the value of the "halt" parameter. The second
 | 
| -**   argument must be one of the SQLITEASYNC_HALT_XXX symbols defined
 | 
| -**   below (either NEVER, IDLE and NOW).
 | 
| -**
 | 
| -**   If the parameter is set to NEVER, then calls to sqlite3async_run()
 | 
| -**   never return. This is the default setting. If the parameter is set
 | 
| -**   to IDLE, then calls to sqlite3async_run() return as soon as the
 | 
| -**   queue of pending write operations is empty. If the parameter is set
 | 
| -**   to NOW, then calls to sqlite3async_run() return as quickly as 
 | 
| -**   possible, without processing any pending write requests.
 | 
| -**
 | 
| -**   If an attempt is made to set this parameter to an integer value other
 | 
| -**   than SQLITEASYNC_HALT_NEVER, IDLE or NOW, then sqlite3async_control() 
 | 
| -**   returns SQLITE_MISUSE and the current value of the parameter is not 
 | 
| -**   modified.
 | 
| -**
 | 
| -**   Modifying the "halt" parameter affects calls to sqlite3async_run() 
 | 
| -**   made by other threads that are currently in progress.
 | 
| -**
 | 
| -** SQLITEASYNC_DELAY:
 | 
| -**
 | 
| -**   This is used to set the value of the "delay" parameter. If set to
 | 
| -**   a non-zero value, then after completing a pending write request, the
 | 
| -**   sqlite3async_run() function sleeps for the configured number of 
 | 
| -**   milliseconds.
 | 
| -**
 | 
| -**   If an attempt is made to set this parameter to a negative value,
 | 
| -**   sqlite3async_control() returns SQLITE_MISUSE and the current value
 | 
| -**   of the parameter is not modified.
 | 
| -**
 | 
| -**   Modifying the "delay" parameter affects calls to sqlite3async_run() 
 | 
| -**   made by other threads that are currently in progress.
 | 
| -**
 | 
| -** SQLITEASYNC_LOCKFILES:
 | 
| -**
 | 
| -**   This is used to set the value of the "lockfiles" parameter. This
 | 
| -**   parameter must be set to either 0 or 1. If set to 1, then the
 | 
| -**   asynchronous IO VFS uses the xLock() and xUnlock() methods of the
 | 
| -**   parent VFS to lock database files being read and/or written. If
 | 
| -**   the parameter is set to 0, then these locks are omitted.
 | 
| -**
 | 
| -**   This parameter may only be set when there are no open database
 | 
| -**   connections using the VFS and the queue of pending write requests
 | 
| -**   is empty. Attempting to set it when this is not true, or to set it 
 | 
| -**   to a value other than 0 or 1 causes sqlite3async_control() to return
 | 
| -**   SQLITE_MISUSE and the value of the parameter to remain unchanged.
 | 
| -**
 | 
| -**   If this parameter is set to zero, then it is only safe to access the
 | 
| -**   database via the asynchronous IO VFS from within a single process. If
 | 
| -**   while writing to the database via the asynchronous IO VFS the database
 | 
| -**   is also read or written from within another process, or via another
 | 
| -**   connection that does not use the asynchronous IO VFS within the same
 | 
| -**   process, the results are undefined (and may include crashes or database
 | 
| -**   corruption).
 | 
| -**
 | 
| -**   Alternatively, if this parameter is set to 1, then it is safe to access
 | 
| -**   the database from multiple connections within multiple processes using
 | 
| -**   either the asynchronous IO VFS or the parent VFS directly.
 | 
| -*/
 | 
| -int sqlite3async_control(int op, ...);
 | 
| -
 | 
| -/*
 | 
| -** Values that can be used as the first argument to sqlite3async_control().
 | 
| -*/
 | 
| -#define SQLITEASYNC_HALT          1
 | 
| -#define SQLITEASYNC_GET_HALT      2
 | 
| -#define SQLITEASYNC_DELAY         3
 | 
| -#define SQLITEASYNC_GET_DELAY     4
 | 
| -#define SQLITEASYNC_LOCKFILES     5
 | 
| -#define SQLITEASYNC_GET_LOCKFILES 6
 | 
| -
 | 
| -/*
 | 
| -** If the first argument to sqlite3async_control() is SQLITEASYNC_HALT,
 | 
| -** the second argument should be one of the following.
 | 
| -*/
 | 
| -#define SQLITEASYNC_HALT_NEVER 0       /* Never halt (default value) */
 | 
| -#define SQLITEASYNC_HALT_NOW   1       /* Halt as soon as possible */
 | 
| -#define SQLITEASYNC_HALT_IDLE  2       /* Halt when write-queue is empty */
 | 
| -
 | 
| -#ifdef __cplusplus
 | 
| -}  /* End of the 'extern "C"' block */
 | 
| -#endif
 | 
| -#endif        /* ifndef __SQLITEASYNC_H_ */
 | 
| -
 | 
| 
 |