Retrieve error message from database connection handle

src/backup.rs

@@ -40,7 +40,7 @@ use std::time::Duration;
 
 use crate::ffi;
 
-use crate::error::{error_from_handle, error_from_sqlite_code};
+use crate::error::error_from_handle;
 use crate::{Connection, DatabaseName, Result};
 
 impl Connection {
@@ -169,7 +169,7 @@ pub struct Progress {
 /// A handle to an online backup.
 pub struct Backup<'a, 'b> {
     phantom_from: PhantomData<&'a Connection>,
-    phantom_to: PhantomData<&'b Connection>,
+    to: &'b Connection,
     b: *mut ffi::sqlite3_backup,
 }
 
@@ -223,7 +223,7 @@ impl Backup<'_, '_> {
 
         Ok(Backup {
             phantom_from: PhantomData,
-            phantom_to: PhantomData,
+            to,
             b,
         })
     }
@@ -263,7 +263,7 @@ impl Backup<'_, '_> {
             ffi::SQLITE_OK => Ok(More),
             ffi::SQLITE_BUSY => Ok(Busy),
             ffi::SQLITE_LOCKED => Ok(Locked),
-            _ => Err(error_from_sqlite_code(rc, None)),
+            _ => self.to.decode_result(rc).map(|_| More),
         }
     }
 

src/blob/pos_io.rs

@@ -44,15 +44,14 @@ impl<'conn> Blob<'conn> {
         //    losslessly converted to i32, since `len` came from an i32.
         // Sanity check the above.
         debug_assert!(i32::try_from(write_start).is_ok() && i32::try_from(buf.len()).is_ok());
-        unsafe {
-            check!(ffi::sqlite3_blob_write(
+        self.conn.decode_result(unsafe {
+            ffi::sqlite3_blob_write(
                 self.blob,
                 buf.as_ptr() as *const _,
                 buf.len() as i32,
                 write_start as i32,
-            ));
-        }
-        Ok(())
+            )
+        })
     }
 
     /// An alias for `write_at` provided for compatibility with the conceptually
@@ -151,12 +150,12 @@ impl<'conn> Blob<'conn> {
         debug_assert!(i32::try_from(read_len).is_ok());
 
         unsafe {
-            check!(ffi::sqlite3_blob_read(
+            self.conn.decode_result(ffi::sqlite3_blob_read(
                 self.blob,
                 buf.as_mut_ptr() as *mut _,
                 read_len as i32,
                 read_start as i32,
-            ));
+            ))?;
 
             Ok(from_raw_parts_mut(buf.as_mut_ptr() as *mut u8, read_len))
         }