refactor(sqlite): make background thread responsible for all FFI calls

Cargo.toml

@@ -150,7 +150,9 @@ paste = "1.0.1"
 serde = { version = "1.0.111", features = ["derive"] }
 serde_json = "1.0.53"
 url = "2.1.1"
-
+rand = "0.8.4"
+rand_xoshiro = "0.6.0"
+hex = "0.4"
 #
 # Any
 #

sqlx-core/Cargo.toml

@@ -43,7 +43,7 @@ mysql = [
     "rand",
     "rsa",
 ]
-sqlite = ["libsqlite3-sys"]
+sqlite = ["libsqlite3-sys", "futures-executor", "flume"]
 mssql = ["uuid", "encoding_rs", "regex"]
 any = []
 
@@ -122,6 +122,9 @@ futures-channel = { version = "0.3.5", default-features = false, features = ["si
 futures-core = { version = "0.3.5", default-features = false }
 futures-intrusive = "0.4.0"
 futures-util = { version = "0.3.5", default-features = false, features = ["alloc", "sink"] }
+# used by the SQLite worker thread to block on the async mutex that locks the database handle
+futures-executor = { version = "0.3.17", optional = true }
+flume = { version = "0.10.9", optional = true, default-features = false, features = ["async"] }
 generic-array = { version = "0.14.4", default-features = false, optional = true }
 hex = "0.4.2"
 hmac = { version = "0.11.0", default-features = false, optional = true }

sqlx-core/src/common/mod.rs

@@ -1,3 +1,28 @@
 mod statement_cache;
 
 pub(crate) use statement_cache::StatementCache;
+use std::fmt::{Debug, Formatter};
+use std::ops::{Deref, DerefMut};
+
+/// A wrapper for `Fn`s that provides a debug impl that just says "Function"
+pub(crate) struct DebugFn<F: ?Sized>(pub F);
+
+impl<F: ?Sized> Deref for DebugFn<F> {
+    type Target = F;
+
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
+
+impl<F: ?Sized> DerefMut for DebugFn<F> {
+    fn deref_mut(&mut self) -> &mut Self::Target {
+        &mut self.0
+    }
+}
+
+impl<F: ?Sized> Debug for DebugFn<F> {
+    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+        f.debug_tuple("Function").finish()
+    }
+}

sqlx-core/src/error.rs

@@ -39,7 +39,7 @@ pub enum Error {
     Database(#[source] Box<dyn DatabaseError>),
 
     /// Error communicating with the database backend.
-    #[error("error communicating with the server: {0}")]
+    #[error("error communicating with database: {0}")]
     Io(#[from] io::Error),
 
     /// Error occurred while attempting to establish a TLS connection.

sqlx-core/src/sqlite/arguments.rs

@@ -31,6 +31,16 @@ impl<'q> SqliteArguments<'q> {
             self.values.push(SqliteArgumentValue::Null);
         }
     }
+
+    pub(crate) fn into_static(self) -> SqliteArguments<'static> {
+        SqliteArguments {
+            values: self
+                .values
+                .into_iter()
+                .map(SqliteArgumentValue::into_static)
+                .collect(),
+        }
+    }
 }
 
 impl<'q> Arguments<'q> for SqliteArguments<'q> {
@@ -49,7 +59,7 @@ impl<'q> Arguments<'q> for SqliteArguments<'q> {
 }
 
 impl SqliteArguments<'_> {
-    pub(super) fn bind(&self, handle: &StatementHandle, offset: usize) -> Result<usize, Error> {
+    pub(super) fn bind(&self, handle: &mut StatementHandle, offset: usize) -> Result<usize, Error> {
         let mut arg_i = offset;
         // for handle in &statement.handles {
 
@@ -95,7 +105,20 @@ impl SqliteArguments<'_> {
 }
 
 impl SqliteArgumentValue<'_> {
-    fn bind(&self, handle: &StatementHandle, i: usize) -> Result<(), Error> {
+    fn into_static(self) -> SqliteArgumentValue<'static> {
+        use SqliteArgumentValue::*;
+
+        match self {
+            Null => Null,
+            Text(text) => Text(text.into_owned().into()),
+            Blob(blob) => Blob(blob.into_owned().into()),
+            Int(v) => Int(v),
+            Int64(v) => Int64(v),
+            Double(v) => Double(v),
+        }
+    }
+
+    fn bind(&self, handle: &mut StatementHandle, i: usize) -> Result<(), Error> {
         use SqliteArgumentValue::*;
 
         let status = match self {