sqlite3_ext

Create SQLite loadable extensions in Rust. The design philosophy of the API is gradual enhancement: all use of SQLite features returns a Result, and an Err is returned when the host version of SQLite does not support the feature in question.

Early Version Warning

This crate is pre-1.0 and the API is allowed to change freely. In particular, if a safe API is found to be unsafe, it will be changed. Once the crate reaches version 1.0, the API will be subject to semantic versioning.

Being a pre-1.0, young crate, there may be bugs which have not yet been discovered. The crate comes with a modest test suite covering all of the features (over 100 tests currently).

Crate documentation is moderately covered, and there are example extensions in the repository that can serve as a guide. Also look at the integration test in the "test" folder at the root.

Multi-threading support is low-priority and untested. If your application-defined functions and virtual tables don't reference data outside of the database they are attached to, this will not cause issues because SQLite always does database operations in a single thread. However, the API needs to be evaluated through a multithreading lens to ensure that it is safe.

Features

• A querying interface similar to Rusqlite's.
• Application-defined scalar and aggregate functions, and collating sequences.
• A more comprehensive virtual table implementation than any other Rust crate currently published, supporting all SQLite virtual table methods.
• Rust support for the most modern features of SQLite, up to version 3.38.5.

Crate features

• static - The consumer of this crate is a statically linked run-time loadable extension. SQLite will be provided by the linker. To avoid link errors, sqlite3_ext disables all APIs that are added after 3.6.8.
• static_modern - Same as static, but sqlite3_ext does not disable any APIs. This will cause link errors if the linked version of SQLite is older than the version supported by sqlite3_ext.
• bundled - Same as static_modern, but also statically link a bundled version of SQLite from libsqlite3-sys. Please do not activate this feature from library crates, so that the consumer of your crate can decide for themselves to enable it.
• with_rusqlite - Adds support for registering your statically linked extension to a Rusqlite Connection object.

How to use

• I want to create a loadable extension that can be used by any SQLite client, or from the sqlite3 shell.
  • Your crate should be crate-type = [ "cdylib" ].
  • Use sqlite3_ext_main to register your enhancements.
  • SQLite methods are provided by SQLite at run-time, and methods will return Error::VersionNotSatisfied if they are not available in the host SQLite.
• I want to create a Rust binary that uses features not supported by rusqlite.
  • Your crate can be of any type. Enable the with_rusqlite and bundled features of this crate.
  • Use sqlite3_ext_init to create an initialization function. Call the function with the rusqlite Connection, as shown here.
  • SQLite methods will always be available, since the SQLite version is controlled by Rust.
• I want to create a statically linked extension that can be used by a (potentially non-Rust) program.
  • Your crate should be crate-type = [ "staticlib" ]. Enable the static feature of this crate. Use sqlite3_ext_main to register your enhancements.
  • Call sqlite3_mycrate_init directly (the method name is derived from the crate name) as documented here, or use sqlite3_auto_extension.
  • The host system provides SQLite. SQLite methods not available in version 3.6.8 will always return Error::VersionNotSatisfied.
• I want to create a statically linked extension with modern SQLite features that can be used by a (potentially non-Rust) program.
  • This is the same as above, but using the static_modern feature.
  • The version of SQLite being linked in must be the same or newer than the version supported by sqlite3_ext.
• I want to create a Rust program that does not use rusqlite.
  • Your crate can be of any type. Enable the bundled feature of this crate.
  • Use sqlite3_ext_init to create an initialization function. Use Database to open a connection to a database. Pass the Database to the init function.
  • SQLite methods will always be available, since the SQLite version is controlled by Rust.
  • Note: if you are publishing a library crate, use static_modern instead of bundled, and expose a bundled feature in your own crate and have it enable the sqlite3_ext/bundled feature. This is to avoid corrupting the database of your library's consumer.

Test configurations

Tests run with modern SQLite:

• All tests from Cargo.toml with crate feature static.
• All tests from Cargo.toml with crate feature static_modern.

Todo:

• Run tests against SQLite 3.6.8.

Interfaces supported

Here is a compatibility chart showing which parts of the SQLite API are currently covered by sqlite3_ext. Iconography:

• ✅ - This API is fully exposed via an API in sqlite3_ext
• ❕ - This API is available via unsafe ffi, but there are no plans to make an API for it in sqlite3_ext.

Interface	Object	Status	Details
sqlite3_aggregate_context	sqlite3_context	✅	Arbitrary structs supported
sqlite3_auto_extension	-	✅	Extension::register_auto
sqlite3_autovacuum_pages
sqlite3_backup_finish
sqlite3_backup_init
sqlite3_backup_pagecount
sqlite3_backup_remaining
sqlite3_backup_step
sqlite3_bind_blob	sqlite3_stmt	✅	ToParam
sqlite3_bind_blob64	sqlite3_stmt	✅	ToParam
sqlite3_bind_double	sqlite3_stmt	✅	ToParam
sqlite3_bind_int	sqlite3_stmt	❕	Unnecessary
sqlite3_bind_int64	sqlite3_stmt	✅	ToParam
sqlite3_bind_null	sqlite3_stmt	✅	ToParam
sqlite3_bind_parameter_count	sqlite3_stmt	✅	Statement::parameter_count
sqlite3_bind_parameter_index	sqlite3_stmt	✅	Statement::parameter_position
sqlite3_bind_parameter_name	sqlite3_stmt	✅	Statement::parameter_name
sqlite3_bind_pointer	sqlite3_stmt	✅	ToParam
sqlite3_bind_text	sqlite3_stmt	✅	ToParam
sqlite3_bind_text16	sqlite3_stmt	❕	Use UTF-8 equivalent
sqlite3_bind_text64	sqlite3_stmt	✅	ToParam
sqlite3_bind_value	sqlite3_stmt	✅	ToParam
sqlite3_bind_zeroblob	sqlite3_stmt
sqlite3_bind_zeroblob64	sqlite3_stmt
sqlite3_blob_bytes
sqlite3_blob_close
sqlite3_blob_open
sqlite3_blob_read
sqlite3_blob_reopen
sqlite3_blob_write
sqlite3_busy_handler
sqlite3_busy_timeout
sqlite3_cancel_auto_extension	-	✅	Extension::cancel_auto
sqlite3_changes		✅	Statement::execute
sqlite3_changes64		✅	Statement::execute
sqlite3_clear_bindings	sqlite3_stmt	❕	Unnecessary
sqlite3_close		✅	Database::close
sqlite3_close_v2		❕	Unnecessary
sqlite3_collation_needed	sqlite3	✅	Connection::set_collation_needed_func
sqlite3_collation_needed16	sqlite3	❕	Use UTF-8 equivalent
sqlite3_column_blob	sqlite3_stmt	✅	Column::get_blob
sqlite3_column_bytes	sqlite3_stmt	❕	Unnecessary
sqlite3_column_bytes16	sqlite3_stmt	❕	Use UTF-8 equivalent
sqlite3_column_count	sqlite3_stmt	✅	Statement::column_count
sqlite3_column_database_name	sqlite3_stmt	✅	Column::database_name
sqlite3_column_database_name16	sqlite3_stmt	❕	Use UTF-8 equivalent
sqlite3_column_decltype	sqlite3_stmt	✅	Column::decltype
sqlite3_column_decltype16	sqlite3_stmt	❕	Use UTF-8 equivalent
sqlite3_column_double	sqlite3_stmt	✅	Column::get_f64
sqlite3_column_int	sqlite3_stmt	✅	Column::get_i32
sqlite3_column_int64	sqlite3_stmt	✅	Column::get_i64
sqlite3_column_name	sqlite3_stmt	✅	Column::name
sqlite3_column_name16	sqlite3_stmt	❕	Use UTF-8 equivalent
sqlite3_column_origin_name	sqlite3_stmt	✅	Column::origin_name
sqlite3_column_origin_name16	sqlite3_stmt	❕	Use UTF-8 equivalent
sqlite3_column_table_name	sqlite3_stmt	✅	Column::table_name
sqlite3_column_table_name16	sqlite3_stmt	❕	Use UTF-8 equivalent
sqlite3_column_text	sqlite3_stmt	✅	Column::get_str
sqlite3_column_text16	sqlite3_stmt	❕	Use UTF-8 equivalent
sqlite3_column_type	sqlite3_stmt	✅	Column::value_type
sqlite3_column_value	sqlite3_stmt	✅	Column::as_ref
sqlite3_commit_hook	sqlite3
sqlite3_compileoption_get
sqlite3_compileoption_used
sqlite3_complete
sqlite3_complete16		❕	Use UTF-8 equivalent
sqlite3_config
sqlite3_context_db_handle	sqlite3_context	✅	Context::db
sqlite3_create_collation	sqlite3	✅	Connection::create_collation
sqlite3_create_collation16	sqlite3	❕	Use UTF-8 equivalent
sqlite3_create_collation_v2	sqlite3	✅	Connection::create_collation
sqlite3_create_filename
sqlite3_create_function	sqlite3	✅	Connection::create_scalar_function
sqlite3_create_function16	sqlite3	❕	Use UTF-8 equivalent
sqlite3_create_function_v2	sqlite3	✅	Connection::create_scalar_function
sqlite3_create_module	sqlite3	✅	Connection::create_module
sqlite3_create_module_v2	sqlite3	✅	Connection::create_module
sqlite3_create_window_function	sqlite3	✅	Connection::create_aggregate_function
sqlite3_data_count	sqlite3_stmt
sqlite3_database_file_object
sqlite3_db_cacheflush
sqlite3_db_config
sqlite3_db_filename
sqlite3_db_handle	sqlite3_stmt	✅	Statement::db
sqlite3_db_mutex	sqlite3	✅	Connection::lock
sqlite3_db_readonly
sqlite3_db_release_memory
sqlite3_db_status
sqlite3_declare_vtab		✅	VTab::connect
sqlite3_deserialize
sqlite3_drop_modules
sqlite3_enable_load_extension	sqlite3	❕	Available via ffi
sqlite3_enable_shared_cache
sqlite3_errcode	sqlite3
sqlite3_errmsg	sqlite3
sqlite3_errmsg16	sqlite3	❕	Use UTF-8 equivalent
sqlite3_error_offset	sqlite3
sqlite3_errstr	-	✅	Error::fmt
sqlite3_exec	sqlite3	❕	Unnecessary
sqlite3_expanded_sql	sqlite3_stmt
sqlite3_extended_errcode	sqlite3
sqlite3_extended_result_codes	sqlite3
sqlite3_file_control
sqlite3_filename_database
sqlite3_filename_journal
sqlite3_filename_wal
sqlite3_finalize	sqlite3_stmt	❕	Unnecessary
sqlite3_free		❕	Available via ffi
sqlite3_free_filename
sqlite3_free_table		❕	Available via ffi
sqlite3_get_autocommit
sqlite3_get_auxdata	sqlite3_context	✅	Context::aux_data
sqlite3_get_table		❕	Available via ffi
sqlite3_hard_heap_limit64
sqlite3_initialize		❕	Available via ffi
sqlite3_interrupt
sqlite3_keyword_check
sqlite3_keyword_count
sqlite3_keyword_name
sqlite3_last_insert_rowid
sqlite3_libversion		✅	SQLITE_VERSION.as_str
sqlite3_libversion_number		✅	SQLITE_VERSION.get
sqlite3_limit	sqlite3
sqlite3_load_extension	sqlite3
sqlite3_log
sqlite3_malloc		❕	Available via ffi
sqlite3_malloc64		❕	Available via ffi
sqlite3_memory_highwater
sqlite3_memory_used
sqlite3_mprintf	char	❕	Available via ffi
sqlite3_msize		❕	Available via ffi
sqlite3_mutex_alloc		❕	Available via ffi
sqlite3_mutex_enter		❕	Available via ffi
sqlite3_mutex_free		❕	Available via ffi
sqlite3_mutex_held		❕	Available via ffi
sqlite3_mutex_leave		❕	Available via ffi
sqlite3_mutex_notheld		❕	Available via ffi
sqlite3_mutex_try		❕	Available via ffi
sqlite3_next_stmt
sqlite3_normalized_sql	sqlite3_stmt
sqlite3_open	sqlite3
sqlite3_open16	sqlite3	❕	Use UTF-8 equivalent
sqlite3_open_v2	sqlite3
sqlite3_overload_function	sqlite3	✅	Connection::create_overloaded_function
sqlite3_prepare	sqlite3_stmt	❕	Unnecessary
sqlite3_prepare16	sqlite3_stmt	❕	Use UTF-8 equivalent
sqlite3_prepare16_v2	sqlite3_stmt	❕	Use UTF-8 equivalent
sqlite3_prepare16_v3	sqlite3_stmt	❕	Use UTF-8 equivalent
sqlite3_prepare_v2	sqlite3_stmt	✅	Connection::prepare
sqlite3_prepare_v3	sqlite3_stmt	✅	Connection::prepare
sqlite3_preupdate_blobwrite
sqlite3_preupdate_count
sqlite3_preupdate_depth
sqlite3_preupdate_hook
sqlite3_preupdate_new
sqlite3_preupdate_old
sqlite3_profile
sqlite3_progress_handler
sqlite3_randomness		✅	sqlite3_randomness
sqlite3_realloc		❕	Available via ffi
sqlite3_realloc64		❕	Available via ffi
sqlite3_release_memory
sqlite3_reset	sqlite3_stmt	✅	Statement::query
sqlite3_reset_auto_extension		✅	Extension::reset_auto
sqlite3_result_blob	sqlite3_context	✅	ToContextResult
sqlite3_result_blob64	sqlite3_context	✅	ToContextResult
sqlite3_result_double	sqlite3_context	✅	ToContextResult
sqlite3_result_error	sqlite3_context	✅	ToContextResult
sqlite3_result_error16	sqlite3_context	❕	Use UTF-8 equivalent
sqlite3_result_error_code	sqlite3_context	✅	ToContextResult
sqlite3_result_error_nomem	sqlite3_context
sqlite3_result_error_toobig	sqlite3_context
sqlite3_result_int	sqlite3_context	✅	ToContextResult
sqlite3_result_int64	sqlite3_context	✅	ToContextResult
sqlite3_result_null	sqlite3_context	✅	ToContextResult
sqlite3_result_pointer	sqlite3_context	✅	PassedRef
sqlite3_result_subtype	sqlite3_context	✅	UnsafePtr
sqlite3_result_text	sqlite3_context	✅	ToContextResult
sqlite3_result_text16	sqlite3_context	❕	Use UTF-8 equivalent
sqlite3_result_text16be	sqlite3_context	❕	Use UTF-8 equivalent
sqlite3_result_text16le	sqlite3_context	❕	Use UTF-8 equivalent
sqlite3_result_text64	sqlite3_context	✅	ToContextResult
sqlite3_result_value	sqlite3_context	✅	ToContextResult
sqlite3_result_zeroblob	sqlite3_context
sqlite3_result_zeroblob64	sqlite3_context
sqlite3_rollback_hook	sqlite3
sqlite3_serialize
sqlite3_set_authorizer
sqlite3_set_auxdata	sqlite3_context	✅	Context::set_aux_data
sqlite3_set_last_insert_rowid	sqlite3	❕	Available via ffi
sqlite3_shutdown		❕	Available via ffi
sqlite3_sleep		❕	Available via ffi
sqlite3_snapshot_cmp
sqlite3_snapshot_free
sqlite3_snapshot_get
sqlite3_snapshot_open
sqlite3_snapshot_recover
sqlite3_snprintf	char	❕	Available via ffi
sqlite3_soft_heap_limit64
sqlite3_sourceid		✅	SQLITE_VERSION.sourceid
sqlite3_sql	sqlite3_stmt	✅	Statement::sql
sqlite3_status
sqlite3_status64
sqlite3_step	sqlite3_stmt	✅	ResultSet::next
sqlite3_stmt_busy	sqlite3_stmt
sqlite3_stmt_isexplain	sqlite3_stmt
sqlite3_stmt_readonly	sqlite3_stmt
sqlite3_stmt_scanstatus	sqlite3_stmt
sqlite3_stmt_scanstatus_reset	sqlite3_stmt
sqlite3_stmt_status	sqlite3_stmt
sqlite3_str_append	sqlite3_str	❕	Available via ffi
sqlite3_str_appendall	sqlite3_str	❕	Available via ffi
sqlite3_str_appendchar	sqlite3_str	❕	Available via ffi
sqlite3_str_appendf	sqlite3_str	❕	Available via ffi
sqlite3_str_errcode	sqlite3_str	❕	Available via ffi
sqlite3_str_finish	sqlite3_str	❕	Available via ffi
sqlite3_str_length	sqlite3_str	❕	Available via ffi
sqlite3_str_new	sqlite3_str	❕	Available via ffi
sqlite3_str_reset	sqlite3_str	❕	Available via ffi
sqlite3_str_value	sqlite3_str	❕	Available via ffi
sqlite3_str_vappendf	sqlite3_str	❕	Available via ffi
sqlite3_strglob	char	✅	sqlite3_strglob
sqlite3_stricmp	char	✅	sqlite3_stricmp
sqlite3_strlike	char	✅	sqlite3_strlike
sqlite3_strnicmp	char	❕	Unnecessary
sqlite3_system_errno	sqlite3	❕	Available via ffi
sqlite3_table_column_metadata
sqlite3_threadsafe		❕	Available via ffi
sqlite3_total_changes	sqlite3
sqlite3_total_changes64	sqlite3
sqlite3_trace
sqlite3_trace_v2
sqlite3_txn_state
sqlite3_unlock_notify
sqlite3_update_hook
sqlite3_uri_boolean		❕	Available via ffi
sqlite3_uri_int64		❕	Available via ffi
sqlite3_uri_key		❕	Available via ffi
sqlite3_uri_parameter		❕	Available via ffi
sqlite3_user_data	sqlite3_context	✅	Use a closure for the function
sqlite3_value_blob	sqlite3_value	✅	ValueRef::get_blob
sqlite3_value_bytes	sqlite3_value	❕	Unnecessary
sqlite3_value_bytes16	sqlite3_value	❕	Use UTF-8 equivalent
sqlite3_value_double	sqlite3_value	✅	ValueRef::get_f64
sqlite3_value_dup	sqlite3_value
sqlite3_value_free	sqlite3_value	❕	Unnecesary
sqlite3_value_frombind	sqlite3_value	✅	ValueRef::is_from_bind
sqlite3_value_int	sqlite3_value	✅	ValueRef::get_i32
sqlite3_value_int64	sqlite3_value	✅	ValueRef::get_i64
sqlite3_value_nochange	sqlite3_value	✅	ValueRef::nochange
sqlite3_value_numeric_type	sqlite3_value	✅	ValueRef::numeric_type
sqlite3_value_pointer	sqlite3_value	✅	ValueRef::get_ref
sqlite3_value_subtype	sqlite3_value	✅	UnsafePtr
sqlite3_value_text	sqlite3_value	✅	ValueRef::get_str
sqlite3_value_text16	sqlite3_value	❕	Use UTF-8 equivalent
sqlite3_value_text16be	sqlite3_value	❕	Use UTF-8 equivalent
sqlite3_value_text16le	sqlite3_value	❕	Use UTF-8 equivalent
sqlite3_value_type	sqlite3_value	✅	ValueRef::value_type
sqlite3_vfs_find
sqlite3_vfs_register
sqlite3_vfs_unregister
sqlite3_vmprintf	char	❕	Unnecessary
sqlite3_vsnprintf	char	❕	Unnecessary
sqlite3_vtab_collation	sqlite3_index_info	✅	IndexInfoConstraint::collation
sqlite3_vtab_config	sqlite3	✅	VTabConnection
sqlite3_vtab_distinct	sqlite3_index_info	✅	IndexInfo::distinct_mode
sqlite3_vtab_in	sqlite3_index_info	✅	IndexInfoConstraint::set_value_list_wanted
sqlite3_vtab_in_first	sqlite3_value	✅	ValueList
sqlite3_vtab_in_next	sqlite3_value	✅	ValueList
sqlite3_vtab_nochange	sqlite3_context	✅	ColumnContext::nochange
sqlite3_vtab_on_conflict	sqlite3	✅	ChangeInfo::conflict_mode
sqlite3_vtab_rhs_value	sqlite3_index_info	✅	IndexInfoConstraint::rhs
sqlite3_wal_autocheckpoint
sqlite3_wal_checkpoint
sqlite3_wal_checkpoint_v2
sqlite3_wal_hook
sqlite3_win32_set_directory
sqlite3_win32_set_directory16		❕	Use UTF-8 equivalent
sqlite3_win32_set_directory8