sqlite: expose backup api

doc/api/sqlite.md

@@ -526,6 +526,63 @@ exception.
 | `TEXT`    | {string}                   |
 | `BLOB`    | {TypedArray} or {DataView} |
 
+## `sqlite.backup(sourceDb, destination[, options])`
+
+<!-- YAML
+added: REPLACEME
+-->
+
+* `sourceDb` {DatabaseSync} The database to backup. The source database must be open.
+* `destination` {string} The path where the backup will be created. If the file already exists, the contents will be
+  overwritten.
+* `options` {Object} Optional configuration for the backup. The
+  following properties are supported:
+  * `source` {string} Name of the source database. This can be `'main'` (the default primary database) or any other
+    database that have been added with [`ATTACH DATABASE`][] **Default:** `'main'`.
+  * `target` {string} Name of the target database. This can be `'main'` (the default primary database) or any other
+    database that have been added with [`ATTACH DATABASE`][] **Default:** `'main'`.
+  * `rate` {number} Number of pages to be transmitted in each batch of the backup. **Default:** `100`.
+  * `progress` {Function} Callback function that will be called with the number of pages copied and the total number of
+    pages.
+* Returns: {Promise} A promise that resolves when the backup is completed and rejects if an error occurs.
+
+This method makes a database backup. This method abstracts the [`sqlite3_backup_init()`][], [`sqlite3_backup_step()`][]
+and [`sqlite3_backup_finish()`][] functions.
+
+The backed-up database can be used normally during the backup process. Mutations coming from the same connection - same
+{DatabaseSync} - object will be reflected in the backup right away. However, mutations from other connections will cause
+the backup process to restart.
+
+```cjs
+const { backup, DatabaseSync } = require('node:sqlite');
+
+(async () => {
+  const sourceDb = new DatabaseSync('source.db');
+  const totalPagesTransferred = await backup(sourceDb, 'backup.db', {
+    rate: 1, // Copy one page at a time.
+    progress: ({ totalPages, remainingPages }) => {
+      console.log('Backup in progress', { totalPages, remainingPages });
+    },
+  });
+
+  console.log('Backup completed', totalPagesTransferred);
+})();
+```
+
+```mjs
+import { backup, DatabaseSync } from 'node:sqlite';
+
+const sourceDb = new DatabaseSync('source.db');
+const totalPagesTransferred = await backup(sourceDb, 'backup.db', {
+  rate: 1, // Copy one page at a time.
+  progress: ({ totalPages, remainingPages }) => {
+    console.log('Backup in progress', { totalPages, remainingPages });
+  },
+});
+
+console.log('Backup completed', totalPagesTransferred);
+```
+
 ## `sqlite.constants`
 
 <!-- YAML
@@ -609,6 +666,9 @@ resolution handler passed to [`database.applyChangeset()`][]. See also
 [`SQLITE_DIRECTONLY`]: https://www.sqlite.org/c3ref/c_deterministic.html
 [`SQLITE_MAX_FUNCTION_ARG`]: https://www.sqlite.org/limits.html#max_function_arg
 [`database.applyChangeset()`]: #databaseapplychangesetchangeset-options
+[`sqlite3_backup_finish()`]: https://www.sqlite.org/c3ref/backup_finish.html#sqlite3backupfinish
+[`sqlite3_backup_init()`]: https://www.sqlite.org/c3ref/backup_finish.html#sqlite3backupinit
+[`sqlite3_backup_step()`]: https://www.sqlite.org/c3ref/backup_finish.html#sqlite3backupstep
 [`sqlite3_changes64()`]: https://www.sqlite.org/c3ref/changes.html
 [`sqlite3_close_v2()`]: https://www.sqlite.org/c3ref/close.html
 [`sqlite3_create_function_v2()`]: https://www.sqlite.org/c3ref/create_function.html

src/env_properties.h

@@ -77,6 +77,7 @@
   V(asn1curve_string, "asn1Curve")                                             \
   V(async_ids_stack_string, "async_ids_stack")                                 \
   V(attributes_string, "attributes")                                           \
+  V(backup_string, "backup")                                                   \
   V(base_string, "base")                                                       \
   V(base_url_string, "baseURL")                                                \
   V(bits_string, "bits")                                                       \
@@ -302,6 +303,7 @@
   V(primordials_string, "primordials")                                         \
   V(priority_string, "priority")                                               \
   V(process_string, "process")                                                 \
+  V(progress_string, "progress")                                               \
   V(promise_string, "promise")                                                 \
   V(protocol_string, "protocol")                                               \
   V(prototype_string, "prototype")                                             \
@@ -316,6 +318,7 @@
   V(reason_string, "reason")                                                   \
   V(refresh_string, "refresh")                                                 \
   V(regexp_string, "regexp")                                                   \
+  V(remaining_pages_string, "remainingPages")                                  \
   V(rename_string, "rename")                                                   \
   V(replacement_string, "replacement")                                         \
   V(required_module_facade_url_string,                                         \
@@ -369,6 +372,7 @@
   V(time_to_first_byte_sent_string, "timeToFirstByteSent")                     \
   V(time_to_first_header_string, "timeToFirstHeader")                          \
   V(tls_ticket_string, "tlsTicket")                                            \
+  V(total_pages_string, "totalPages")                                          \
   V(transfer_string, "transfer")                                               \
   V(transfer_unsupported_type_str,                                             \
     "Cannot transfer object of unsupported type.")                             \