feat: sqlx sqlite expose de/serialize (#3745)

* feat: implement serialze no copy on lockedsqlitehandle

* feat: implement serialize on sqliteconnection

* feat: implement deserialize on sqliteconnection and add sqlitebuf wrapper type

* refactor: misc sqlite type and deserialize refactoring

* chore: misc clippy refactoring

* fix: misc refactoring and fixes

- pass non-owned byte slice to deserialize
- `SqliteBufError` and better error handling
- more impl for `SqliteOnwedBuf` so it can be used as a slice
- default serialize for `SqliteConnection`

* refactor: move serialize and deserialize on worker thread

This implements `Command::Serialize` and `Command::Deserialize` and moves the
serialize and deserialize logic to the worker thread.

`Serialize` will need some more iterations as it's not clear whether it would
need to wait for other write transactions before running.

* refactor: misc refactoring and changes

- Merged deserialize module with serialize module
- Moved `SqliteOwnedBuf` into serialize module
- Fixed rustdocs

* chore: API tweaks, better docs, tests

* fix: unused import

* fix: export `SqliteOwnedBuf`, docs and safety tweaks

---------

Co-authored-by: Austin Bonander <austin.bonander@gmail.com>

Author: mattrighetti

sqlx-core/src/error.rs

@@ -34,6 +34,12 @@ pub enum Error {
     #[error("error with configuration: {0}")]
     Configuration(#[source] BoxDynError),
 
+    /// One or more of the arguments to the called function was invalid.
+    ///
+    /// The string contains more information.
+    #[error("{0}")]
+    InvalidArgument(String),
+
     /// Error returned from the database.
     #[error("error returned from database: {0}")]
     Database(#[source] Box<dyn DatabaseError>),
@@ -79,7 +85,7 @@ pub enum Error {
     },
 
     /// Error occured while encoding a value.
-    #[error("error occured while encoding a value: {0}")]
+    #[error("error occurred while encoding a value: {0}")]
     Encode(#[source] BoxDynError),
 
     /// Error occurred while decoding a value.
@@ -136,6 +142,12 @@ impl Error {
         Error::Protocol(err.to_string())
     }
 
+    #[doc(hidden)]
+    #[inline]
+    pub fn database(err: impl DatabaseError) -> Self {
+        Error::Database(Box::new(err))
+    }
+
     #[doc(hidden)]
     #[inline]
     pub fn config(err: impl StdError + Send + Sync + 'static) -> Self {

sqlx-sqlite/src/connection/collation.rs

@@ -10,7 +10,6 @@ use libsqlite3_sys::{sqlite3_create_collation_v2, SQLITE_OK, SQLITE_UTF8};
 
 use crate::connection::handle::ConnectionHandle;
 use crate::error::Error;
-use crate::SqliteError;
 
 #[derive(Clone)]
 pub struct Collation {
@@ -67,7 +66,7 @@ impl Collation {
         } else {
             // The xDestroy callback is not called if the sqlite3_create_collation_v2() function fails.
             drop(unsafe { Arc::from_raw(raw_f) });
-            Err(Error::Database(Box::new(SqliteError::new(handle.as_ptr()))))
+            Err(handle.expect_error().into())
         }
     }
 }
@@ -112,7 +111,7 @@ where
     } else {
         // The xDestroy callback is not called if the sqlite3_create_collation_v2() function fails.
         drop(unsafe { Box::from_raw(boxed_f) });
-        Err(Error::Database(Box::new(SqliteError::new(handle.as_ptr()))))
+        Err(handle.expect_error().into())
     }
 }
 

sqlx-sqlite/src/connection/establish.rs

@@ -204,10 +204,10 @@ impl EstablishParams {
 
         // SAFE: tested for NULL just above
         // This allows any returns below to close this handle with RAII
-        let handle = unsafe { ConnectionHandle::new(handle) };
+        let mut handle = unsafe { ConnectionHandle::new(handle) };
 
         if status != SQLITE_OK {
-            return Err(Error::Database(Box::new(SqliteError::new(handle.as_ptr()))));
+            return Err(Error::Database(Box::new(handle.expect_error())));
         }
 
         // Enable extended result codes
@@ -226,33 +226,29 @@ impl EstablishParams {
             for ext in self.extensions.iter() {
                 // `sqlite3_load_extension` is unusual as it returns its errors via an out-pointer
                 // rather than by calling `sqlite3_errmsg`
-                let mut error = null_mut();
+                let mut error_msg = null_mut();
                 status = unsafe {
                     sqlite3_load_extension(
                         handle.as_ptr(),
                         ext.0.as_ptr(),
                         ext.1.as_ref().map_or(null(), |e| e.as_ptr()),
-                        addr_of_mut!(error),
+                        addr_of_mut!(error_msg),
                     )
                 };
 
                 if status != SQLITE_OK {
+                    let mut e = handle.expect_error();
+
                     // SAFETY: We become responsible for any memory allocation at `&error`, so test
                     // for null and take an RAII version for returns
-                    let err_msg = if !error.is_null() {
-                        unsafe {
-                            let e = CStr::from_ptr(error).into();
-                            sqlite3_free(error as *mut c_void);
-                            e
-                        }
-                    } else {
-                        CString::new("Unknown error when loading extension")
-                            .expect("text should be representable as a CString")
-                    };
-                    return Err(Error::Database(Box::new(SqliteError::extension(
-                        handle.as_ptr(),
-                        &err_msg,
-                    ))));
+                    if !error_msg.is_null() {
+                        e = e.with_message(unsafe {
+                            let msg = CStr::from_ptr(error_msg).to_string_lossy().into();
+                            sqlite3_free(error_msg as *mut c_void);
+                            msg
+                        });
+                    }
+                    return Err(Error::Database(Box::new(e)));
                 }
             } // Preempt any hypothetical security issues arising from leaving ENABLE_LOAD_EXTENSION
               // on by disabling the flag again once we've loaded all the requested modules.
@@ -271,7 +267,7 @@ impl EstablishParams {
             // configure a `regexp` function for sqlite, it does not come with one by default
             let status = crate::regexp::register(handle.as_ptr());
             if status != SQLITE_OK {
-                return Err(Error::Database(Box::new(SqliteError::new(handle.as_ptr()))));
+                return Err(Error::Database(Box::new(handle.expect_error())));
             }
         }
 
@@ -286,7 +282,7 @@ impl EstablishParams {
         status = unsafe { sqlite3_busy_timeout(handle.as_ptr(), ms) };
 
         if status != SQLITE_OK {
-            return Err(Error::Database(Box::new(SqliteError::new(handle.as_ptr()))));
+            return Err(Error::Database(Box::new(handle.expect_error())));
         }
 
         Ok(ConnectionState {

sqlx-sqlite/src/connection/handle.rs

@@ -46,6 +46,17 @@ impl ConnectionHandle {
         unsafe { sqlite3_last_insert_rowid(self.as_ptr()) }
     }
 
+    pub(crate) fn last_error(&mut self) -> Option<SqliteError> {
+        // SAFETY: we have exclusive access to the database handle
+        unsafe { SqliteError::try_new(self.as_ptr()) }
+    }
+
+    #[track_caller]
+    pub(crate) fn expect_error(&mut self) -> SqliteError {
+        self.last_error()
+            .expect("expected error code to be set in current context")
+    }
+
     pub(crate) fn exec(&mut self, query: impl Into<String>) -> Result<(), Error> {
         let query = query.into();
         let query = CString::new(query).map_err(|_| err_protocol!("query contains nul bytes"))?;

sqlx-sqlite/src/connection/mod.rs

@@ -40,6 +40,7 @@ mod handle;
 pub(crate) mod intmap;
 #[cfg(feature = "preupdate-hook")]
 mod preupdate_hook;
+pub(crate) mod serialize;
 
 mod worker;
 
@@ -544,7 +545,7 @@ impl LockedSqliteHandle<'_> {
     }
 
     pub fn last_error(&mut self) -> Option<SqliteError> {
-        SqliteError::try_new(self.guard.handle.as_ptr())
+        self.guard.handle.last_error()
     }
 }