Implement `sqlite3_backup_step`'s multi-step protocol.

1 files changed, 13 insertions, 7 deletions

diff --git a/src/db/backup.rs b/src/db/backup.rs
index 212fa4e..b09bb3d 100644
--- a/src/db/backup.rs
+++ b/src/db/backup.rs
@@ -6,8 +6,7 @@ use std::{
 
 use libsqlite3_sys::{
     sqlite3, sqlite3_backup, sqlite3_backup_finish, sqlite3_backup_init, sqlite3_backup_step,
-    sqlite3_errmsg, sqlite3_errstr, sqlite3_extended_errcode, SQLITE_BUSY, SQLITE_LOCKED,
-    SQLITE_OK,
+    sqlite3_errmsg, sqlite3_errstr, sqlite3_extended_errcode, SQLITE_DONE, SQLITE_OK,
 };
 use sqlx::sqlite::SqlitePool;
 
@@ -43,7 +42,14 @@ impl<'p> Backup<'p> {
         let mut from = from.lock_handle().await?;
 
         let handle = Self::start(to.as_raw_handle(), from.as_raw_handle())?;
-        let step_result = Self::step(handle, -1);
+        let step_result = loop {
+            match Self::step(handle, -1) {
+                Err(error) => break Err(error),
+                Ok(SQLITE_DONE) => break Ok(()),
+                Ok(SQLITE_OK) => (), // keep pumping the backup step function
+                Ok(other) => panic!("unexpected step result: {other}"),
+            }
+        };
         Self::finish(handle)?;
 
         step_result
@@ -72,12 +78,12 @@ impl<'p> Backup<'p> {
         Ok(NonNull::new(handle).expect("backup handle is non-null"))
     }
 
-    fn step(handle: NonNull<sqlite3_backup>, pages: c_int) -> Result<(), Error> {
+    fn step(handle: NonNull<sqlite3_backup>, pages: c_int) -> Result<c_int, Error> {
         let step = unsafe { sqlite3_backup_step(handle.as_ptr(), pages) };
-        if [SQLITE_BUSY, SQLITE_LOCKED].contains(&step) {
-            Err(Error::from_code(step))
+        if [SQLITE_DONE, SQLITE_OK].contains(&step) {
+            Ok(step)
         } else {
-            Ok(())
+            Err(Error::from_code(step))
         }
     }