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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-05 11:19:16 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-07-24 09:53:24 +0000 |
commit | b5f8ee61a7f7e9bd291dd26b0585d03eb686c941 (patch) | |
tree | d4d31289c39fc00da064a825df13a0b98ce95b10 /src/database/sqlite/sqlite3recover.h | |
parent | Adding upstream version 1.44.3. (diff) | |
download | netdata-upstream.tar.xz netdata-upstream.zip |
Adding upstream version 1.46.3.upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'src/database/sqlite/sqlite3recover.h')
-rw-r--r-- | src/database/sqlite/sqlite3recover.h | 249 |
1 files changed, 249 insertions, 0 deletions
diff --git a/src/database/sqlite/sqlite3recover.h b/src/database/sqlite/sqlite3recover.h new file mode 100644 index 000000000..7a1cd1cd8 --- /dev/null +++ b/src/database/sqlite/sqlite3recover.h @@ -0,0 +1,249 @@ +/* +** 2022-08-27 +** +** 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 the public interface to the "recover" extension - +** an SQLite extension designed to recover data from corrupted database +** files. +*/ + +/* +** OVERVIEW: +** +** To use the API to recover data from a corrupted database, an +** application: +** +** 1) Creates an sqlite3_recover handle by calling either +** sqlite3_recover_init() or sqlite3_recover_init_sql(). +** +** 2) Configures the new handle using one or more calls to +** sqlite3_recover_config(). +** +** 3) Executes the recovery by repeatedly calling sqlite3_recover_step() on +** the handle until it returns something other than SQLITE_OK. If it +** returns SQLITE_DONE, then the recovery operation completed without +** error. If it returns some other non-SQLITE_OK value, then an error +** has occurred. +** +** 4) Retrieves any error code and English language error message using the +** sqlite3_recover_errcode() and sqlite3_recover_errmsg() APIs, +** respectively. +** +** 5) Destroys the sqlite3_recover handle and frees all resources +** using sqlite3_recover_finish(). +** +** The application may abandon the recovery operation at any point +** before it is finished by passing the sqlite3_recover handle to +** sqlite3_recover_finish(). This is not an error, but the final state +** of the output database, or the results of running the partial script +** delivered to the SQL callback, are undefined. +*/ + +#ifndef _SQLITE_RECOVER_H +#define _SQLITE_RECOVER_H + +#include "sqlite3.h" + +#ifdef __cplusplus +extern "C" { +#endif + +/* +** An instance of the sqlite3_recover object represents a recovery +** operation in progress. +** +** Constructors: +** +** sqlite3_recover_init() +** sqlite3_recover_init_sql() +** +** Destructor: +** +** sqlite3_recover_finish() +** +** Methods: +** +** sqlite3_recover_config() +** sqlite3_recover_errcode() +** sqlite3_recover_errmsg() +** sqlite3_recover_run() +** sqlite3_recover_step() +*/ +typedef struct sqlite3_recover sqlite3_recover; + +/* +** These two APIs attempt to create and return a new sqlite3_recover object. +** In both cases the first two arguments identify the (possibly +** corrupt) database to recover data from. The first argument is an open +** database handle and the second the name of a database attached to that +** handle (i.e. "main", "temp" or the name of an attached database). +** +** If sqlite3_recover_init() is used to create the new sqlite3_recover +** handle, then data is recovered into a new database, identified by +** string parameter zUri. zUri may be an absolute or relative file path, +** or may be an SQLite URI. If the identified database file already exists, +** it is overwritten. +** +** If sqlite3_recover_init_sql() is invoked, then any recovered data will +** be returned to the user as a series of SQL statements. Executing these +** SQL statements results in the same database as would have been created +** had sqlite3_recover_init() been used. For each SQL statement in the +** output, the callback function passed as the third argument (xSql) is +** invoked once. The first parameter is a passed a copy of the fourth argument +** to this function (pCtx) as its first parameter, and a pointer to a +** nul-terminated buffer containing the SQL statement formated as UTF-8 as +** the second. If the xSql callback returns any value other than SQLITE_OK, +** then processing is immediately abandoned and the value returned used as +** the recover handle error code (see below). +** +** If an out-of-memory error occurs, NULL may be returned instead of +** a valid handle. In all other cases, it is the responsibility of the +** application to avoid resource leaks by ensuring that +** sqlite3_recover_finish() is called on all allocated handles. +*/ +sqlite3_recover *sqlite3_recover_init( + sqlite3* db, + const char *zDb, + const char *zUri +); +sqlite3_recover *sqlite3_recover_init_sql( + sqlite3* db, + const char *zDb, + int (*xSql)(void*, const char*), + void *pCtx +); + +/* +** Configure an sqlite3_recover object that has just been created using +** sqlite3_recover_init() or sqlite3_recover_init_sql(). This function +** may only be called before the first call to sqlite3_recover_step() +** or sqlite3_recover_run() on the object. +** +** The second argument passed to this function must be one of the +** SQLITE_RECOVER_* symbols defined below. Valid values for the third argument +** depend on the specific SQLITE_RECOVER_* symbol in use. +** +** SQLITE_OK is returned if the configuration operation was successful, +** or an SQLite error code otherwise. +*/ +int sqlite3_recover_config(sqlite3_recover*, int op, void *pArg); + +/* +** SQLITE_RECOVER_LOST_AND_FOUND: +** The pArg argument points to a string buffer containing the name +** of a "lost-and-found" table in the output database, or NULL. If +** the argument is non-NULL and the database contains seemingly +** valid pages that cannot be associated with any table in the +** recovered part of the schema, data is extracted from these +** pages to add to the lost-and-found table. +** +** SQLITE_RECOVER_FREELIST_CORRUPT: +** The pArg value must actually be a pointer to a value of type +** int containing value 0 or 1 cast as a (void*). If this option is set +** (argument is 1) and a lost-and-found table has been configured using +** SQLITE_RECOVER_LOST_AND_FOUND, then is assumed that the freelist is +** corrupt and an attempt is made to recover records from pages that +** appear to be linked into the freelist. Otherwise, pages on the freelist +** are ignored. Setting this option can recover more data from the +** database, but often ends up "recovering" deleted records. The default +** value is 0 (clear). +** +** SQLITE_RECOVER_ROWIDS: +** The pArg value must actually be a pointer to a value of type +** int containing value 0 or 1 cast as a (void*). If this option is set +** (argument is 1), then an attempt is made to recover rowid values +** that are not also INTEGER PRIMARY KEY values. If this option is +** clear, then new rowids are assigned to all recovered rows. The +** default value is 1 (set). +** +** SQLITE_RECOVER_SLOWINDEXES: +** The pArg value must actually be a pointer to a value of type +** int containing value 0 or 1 cast as a (void*). If this option is clear +** (argument is 0), then when creating an output database, the recover +** module creates and populates non-UNIQUE indexes right at the end of the +** recovery operation - after all recoverable data has been inserted +** into the new database. This is faster overall, but means that the +** final call to sqlite3_recover_step() for a recovery operation may +** be need to create a large number of indexes, which may be very slow. +** +** Or, if this option is set (argument is 1), then non-UNIQUE indexes +** are created in the output database before it is populated with +** recovered data. This is slower overall, but avoids the slow call +** to sqlite3_recover_step() at the end of the recovery operation. +** +** The default option value is 0. +*/ +#define SQLITE_RECOVER_LOST_AND_FOUND 1 +#define SQLITE_RECOVER_FREELIST_CORRUPT 2 +#define SQLITE_RECOVER_ROWIDS 3 +#define SQLITE_RECOVER_SLOWINDEXES 4 + +/* +** Perform a unit of work towards the recovery operation. This function +** must normally be called multiple times to complete database recovery. +** +** If no error occurs but the recovery operation is not completed, this +** function returns SQLITE_OK. If recovery has been completed successfully +** then SQLITE_DONE is returned. If an error has occurred, then an SQLite +** error code (e.g. SQLITE_IOERR or SQLITE_NOMEM) is returned. It is not +** considered an error if some or all of the data cannot be recovered +** due to database corruption. +** +** Once sqlite3_recover_step() has returned a value other than SQLITE_OK, +** all further such calls on the same recover handle are no-ops that return +** the same non-SQLITE_OK value. +*/ +int sqlite3_recover_step(sqlite3_recover*); + +/* +** Run the recovery operation to completion. Return SQLITE_OK if successful, +** or an SQLite error code otherwise. Calling this function is the same +** as executing: +** +** while( SQLITE_OK==sqlite3_recover_step(p) ); +** return sqlite3_recover_errcode(p); +*/ +int sqlite3_recover_run(sqlite3_recover*); + +/* +** If an error has been encountered during a prior call to +** sqlite3_recover_step(), then this function attempts to return a +** pointer to a buffer containing an English language explanation of +** the error. If no error message is available, or if an out-of memory +** error occurs while attempting to allocate a buffer in which to format +** the error message, NULL is returned. +** +** The returned buffer remains valid until the sqlite3_recover handle is +** destroyed using sqlite3_recover_finish(). +*/ +const char *sqlite3_recover_errmsg(sqlite3_recover*); + +/* +** If this function is called on an sqlite3_recover handle after +** an error occurs, an SQLite error code is returned. Otherwise, SQLITE_OK. +*/ +int sqlite3_recover_errcode(sqlite3_recover*); + +/* +** Clean up a recovery object created by a call to sqlite3_recover_init(). +** The results of using a recovery object with any API after it has been +** passed to this function are undefined. +** +** This function returns the same value as sqlite3_recover_errcode(). +*/ +int sqlite3_recover_finish(sqlite3_recover*); + + +#ifdef __cplusplus +} /* end of the 'extern "C"' block */ +#endif + +#endif /* ifndef _SQLITE_RECOVER_H */ |