feat: allow vfs to be set as uri query parameter (#2013)

* feat: allow vfs to be set as uri query parameter

* fix: handle VFS name as a string

* fix: avoid unnecessary copies of vfs name

sqlx-core/src/sqlite/connection/establish.rs

@@ -67,8 +67,18 @@ impl EstablishParams {
             SQLITE_OPEN_PRIVATECACHE
         };
 
+        let mut query_params: Vec<String> = vec![];
+
         if options.immutable {
-            filename = format!("file:{}?immutable=true", filename);
+            query_params.push("immutable=true".into())
+        }
+
+        if let Some(vfs) = &options.vfs {
+            query_params.push(format!("vfs={}", vfs))
+        }
+
+        if !query_params.is_empty() {
+            filename = format!("file:{}?{}", filename, query_params.join("&"));
             flags |= libsqlite3_sys::SQLITE_OPEN_URI;
         }
 

sqlx-core/src/sqlite/options/mod.rs

@@ -63,6 +63,7 @@ pub struct SqliteConnectOptions {
     pub(crate) busy_timeout: Duration,
     pub(crate) log_settings: LogSettings,
     pub(crate) immutable: bool,
+    pub(crate) vfs: Option<Cow<'static, str>>,
 
     pub(crate) pragmas: IndexMap<Cow<'static, str>, Option<Cow<'static, str>>>,
 
@@ -135,6 +136,7 @@ impl SqliteConnectOptions {
             busy_timeout: Duration::from_secs(5),
             log_settings: Default::default(),
             immutable: false,
+            vfs: None,
             pragmas,
             collations: Default::default(),
             serialized: false,
@@ -367,4 +369,13 @@ impl SqliteConnectOptions {
         self.row_channel_size = size;
         self
     }
+
+    /// Sets the [`vfs`](https://www.sqlite.org/vfs.html) parameter of the database connection.
+    ///
+    /// The default value is empty, and sqlite will use the default VFS object dependeing on the
+    /// operating system.
+    pub fn vfs(mut self, vfs_name: impl Into<Cow<'static, str>>) -> Self {
+        self.vfs = Some(vfs_name.into());
+        self
+    }
 }

sqlx-core/src/sqlite/options/parse.rs

@@ -108,6 +108,8 @@ impl FromStr for SqliteConnectOptions {
                         }
                     },
 
+                    "vfs" => options.vfs = Some(Cow::Owned(value.into_owned())),
+
                     _ => {
                         return Err(Error::Configuration(
                             format!(