1 files changed, 216 insertions, 0 deletions
diff --git a/ext/kv/dynamic.rs b/ext/kv/dynamic.rs
new file mode 100644
index 000000000..f79c10f55
--- /dev/null
+++ b/ext/kv/dynamic.rs
@@ -0,0 +1,216 @@
+// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
+
+use std::cell::RefCell;
+use std::rc::Rc;
+
+use crate::remote::RemoteDbHandlerPermissions;
+use crate::sqlite::SqliteDbHandler;
+use crate::sqlite::SqliteDbHandlerPermissions;
+use crate::AtomicWrite;
+use crate::CommitResult;
+use crate::Database;
+use crate::DatabaseHandler;
+use crate::QueueMessageHandle;
+use crate::ReadRange;
+use crate::ReadRangeOutput;
+use crate::SnapshotReadOptions;
+use async_trait::async_trait;
+use deno_core::error::type_error;
+use deno_core::error::AnyError;
+use deno_core::OpState;
+
+pub struct MultiBackendDbHandler {
+  backends: Vec<(&'static [&'static str], Box<dyn DynamicDbHandler>)>,
+}
+
+impl MultiBackendDbHandler {
+  pub fn new(
+    backends: Vec<(&'static [&'static str], Box<dyn DynamicDbHandler>)>,
+  ) -> Self {
+    Self { backends }
+  }
+
+  pub fn remote_or_sqlite<
+    P: SqliteDbHandlerPermissions + RemoteDbHandlerPermissions + 'static,
+  >(
+    default_storage_dir: Option<std::path::PathBuf>,
+  ) -> Self {
+    Self::new(vec![
+      (
+        &["https://", "http://"],
+        Box::new(crate::remote::RemoteDbHandler::<P>::new()),
+      ),
+      (
+        &[""],
+        Box::new(SqliteDbHandler::<P>::new(default_storage_dir)),
+      ),
+    ])
+  }
+}
+
+#[async_trait(?Send)]
+impl DatabaseHandler for MultiBackendDbHandler {
+  type DB = Box<dyn DynamicDb>;
+
+  async fn open(
+    &self,
+    state: Rc<RefCell<OpState>>,
+    path: Option<String>,
+  ) -> Result<Self::DB, AnyError> {
+    for (prefixes, handler) in &self.backends {
+      for &prefix in *prefixes {
+        if prefix.is_empty() {
+          return handler.dyn_open(state.clone(), path.clone()).await;
+        }
+        let Some(path) = &path else {
+          continue;
+        };
+        if path.starts_with(prefix) {
+          return handler.dyn_open(state.clone(), Some(path.clone())).await;
+        }
+      }
+    }
+    Err(type_error(format!(
+      "No backend supports the given path: {:?}",
+      path
+    )))
+  }
+}
+
+#[async_trait(?Send)]
+pub trait DynamicDbHandler {
+  async fn dyn_open(
+    &self,
+    state: Rc<RefCell<OpState>>,
+    path: Option<String>,
+  ) -> Result<Box<dyn DynamicDb>, AnyError>;
+}
+
+#[async_trait(?Send)]
+impl DatabaseHandler for Box<dyn DynamicDbHandler> {
+  type DB = Box<dyn DynamicDb>;
+
+  async fn open(
+    &self,
+    state: Rc<RefCell<OpState>>,
+    path: Option<String>,
+  ) -> Result<Self::DB, AnyError> {
+    (**self).dyn_open(state, path).await
+  }
+}
+
+#[async_trait(?Send)]
+impl<T, DB> DynamicDbHandler for T
+where
+  T: DatabaseHandler<DB = DB>,
+  DB: Database + 'static,
+{
+  async fn dyn_open(
+    &self,
+    state: Rc<RefCell<OpState>>,
+    path: Option<String>,
+  ) -> Result<Box<dyn DynamicDb>, AnyError> {
+    Ok(Box::new(self.open(state, path).await?))
+  }
+}
+
+#[async_trait(?Send)]
+pub trait DynamicDb {
+  async fn dyn_snapshot_read(
+    &self,
+    state: Rc<RefCell<OpState>>,
+    requests: Vec<ReadRange>,
+    options: SnapshotReadOptions,
+  ) -> Result<Vec<ReadRangeOutput>, AnyError>;
+
+  async fn dyn_atomic_write(
+    &self,
+    state: Rc<RefCell<OpState>>,
+    write: AtomicWrite,
+  ) -> Result<Option<CommitResult>, AnyError>;
+
+  async fn dyn_dequeue_next_message(
+    &self,
+    state: Rc<RefCell<OpState>>,
+  ) -> Result<Box<dyn QueueMessageHandle>, AnyError>;
+
+  fn dyn_close(&self);
+}
+
+#[async_trait(?Send)]
+impl Database for Box<dyn DynamicDb> {
+  type QMH = Box<dyn QueueMessageHandle>;
+
+  async fn snapshot_read(
+    &self,
+    state: Rc<RefCell<OpState>>,
+    requests: Vec<ReadRange>,
+    options: SnapshotReadOptions,
+  ) -> Result<Vec<ReadRangeOutput>, AnyError> {
+    (**self).dyn_snapshot_read(state, requests, options).await
+  }
+
+  async fn atomic_write(
+    &self,
+    state: Rc<RefCell<OpState>>,
+    write: AtomicWrite,
+  ) -> Result<Option<CommitResult>, AnyError> {
+    (**self).dyn_atomic_write(state, write).await
+  }
+
+  async fn dequeue_next_message(
+    &self,
+    state: Rc<RefCell<OpState>>,
+  ) -> Result<Box<dyn QueueMessageHandle>, AnyError> {
+    (**self).dyn_dequeue_next_message(state).await
+  }
+
+  fn close(&self) {
+    (**self).dyn_close()
+  }
+}
+
+#[async_trait(?Send)]
+impl<T, QMH> DynamicDb for T
+where
+  T: Database<QMH = QMH>,
+  QMH: QueueMessageHandle + 'static,
+{
+  async fn dyn_snapshot_read(
+    &self,
+    state: Rc<RefCell<OpState>>,
+    requests: Vec<ReadRange>,
+    options: SnapshotReadOptions,
+  ) -> Result<Vec<ReadRangeOutput>, AnyError> {
+    Ok(self.snapshot_read(state, requests, options).await?)
+  }
+
+  async fn dyn_atomic_write(
+    &self,
+    state: Rc<RefCell<OpState>>,
+    write: AtomicWrite,
+  ) -> Result<Option<CommitResult>, AnyError> {
+    Ok(self.atomic_write(state, write).await?)
+  }
+
+  async fn dyn_dequeue_next_message(
+    &self,
+    state: Rc<RefCell<OpState>>,
+  ) -> Result<Box<dyn QueueMessageHandle>, AnyError> {
+    Ok(Box::new(self.dequeue_next_message(state).await?))
+  }
+
+  fn dyn_close(&self) {
+    self.close()
+  }
+}
+
+#[async_trait(?Send)]
+impl QueueMessageHandle for Box<dyn QueueMessageHandle> {
+  async fn take_payload(&mut self) -> Result<Vec<u8>, AnyError> {
+    (**self).take_payload().await
+  }
+  async fn finish(&self, success: bool) -> Result<(), AnyError> {
+    (**self).finish(success).await
+  }
+}