Index: third_party/sqlite/sqlite-src-3070603/ext/async/sqlite3async.h |
diff --git a/third_party/sqlite/sqlite-src-3070603/ext/async/sqlite3async.h b/third_party/sqlite/sqlite-src-3070603/ext/async/sqlite3async.h |
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+ |
+#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_ */ |
+ |