PDO\SQLite: add support for session extension #21324
Description
Description
The session extension of SQLite provides support for creating changesets and reverting changes to a database: https://sqlite.org/sessionintro.html
Very useful for managing an app database.
It is currently enabled by default in Debian at least.
The best action would probably be to create a new PDO\SQLite\Session class:
PDO\SQLite\Session::__construct(PDO\SQLite $db, string $dbname = 'main')
PDO\SQLite\Session::attach(?string $table): void // pass null to attach all tables of the database
PDO\SQLite\Session::enable(?bool $enable): bool // pass null to return current enabled status
PDO\SQLite\Session::changeset(): PDO\SQLite\Session\Changeset
PDO\SQLite\Session::isEmpty(): bool
PDO\SQLite\Session::diff(string $table, string $dbname = 'main'): void
Deleting the session (sqlite3session_delete) would be handled when the Session object is unloaded from memory.
Starting a session would throw an exception if the session extension is not available.
By default, __construct would set SQLITE_SESSION_OBJCONFIG_ROWID so that even if tables don't have a primary key they could see their changes recorded.
Here are the methods of a changeset:
PDO\SQLite\Session\Changeset::__construct()
PDO\SQLite\Session\Changeset::invert(): void
PDO\SQLite\Session\Changeset::load(?string $serialized_changeset = null): void // Loads an existing serialized changeset
PDO\SQLite\Session\Changeset::iterate(): Generator // iterates, for each iteration, return Change object
PDO\SQLite\Session\Changeset::__toString(): string // serialize the changeset
PDO\SQLite\Session\Changeset::add(PDO\SQLite\Session\Changeset): void // Add a changeset to another one: sqlite3changegroup_add
PDO\SQLite\Session\Changeset::addChange(PDO\SQLite\Session\Change): void // Add a single change: sqlite3changegroup_add_change
PDO\SQLite\Session\Changeset::apply(PDO\SQLite $db, ?callable $filter_callback = null, ?callable $conflict_callback = null)
PDO\SQLite\Session\Change {
string $table;
int $operation;
bool $indirect;
public function new(): array // return new values
public function old(): array // return old values
}
I'm not sure about the interface of the Change object though. Probably needs more work and thought.