Allow extensions to define providers for indexing docs (#13755)

This PR provides extensions with the ability to define providers for
indexing docs.

Release Notes:

- N/A

crates/extension/src/extension_docs_indexer.rs

@@ -0,0 +1,57 @@
+use std::path::PathBuf;
+use std::sync::Arc;
+
+use anyhow::{anyhow, Result};
+use async_trait::async_trait;
+use futures::FutureExt;
+use indexed_docs::{IndexedDocsDatabase, IndexedDocsProvider, PackageName, ProviderId};
+use wasmtime_wasi::WasiView;
+
+use crate::wasm_host::{WasmExtension, WasmHost};
+
+pub struct ExtensionDocsIndexer {
+    pub(crate) extension: WasmExtension,
+    pub(crate) host: Arc<WasmHost>,
+    pub(crate) id: ProviderId,
+}
+
+#[async_trait]
+impl IndexedDocsProvider for ExtensionDocsIndexer {
+    fn id(&self) -> ProviderId {
+        self.id.clone()
+    }
+
+    fn database_path(&self) -> PathBuf {
+        let mut database_path = self.host.work_dir.clone();
+        database_path.push(self.extension.manifest.id.as_ref());
+        database_path.push("docs");
+        database_path.push(format!("{}.0.mdb", self.id));
+
+        database_path
+    }
+
+    async fn index(&self, package: PackageName, database: Arc<IndexedDocsDatabase>) -> Result<()> {
+        self.extension
+            .call({
+                let id = self.id.clone();
+                |extension, store| {
+                    async move {
+                        let database_resource = store.data_mut().table().push(database)?;
+                        extension
+                            .call_index_docs(
+                                store,
+                                id.as_ref(),
+                                package.as_ref(),
+                                database_resource,
+                            )
+                            .await?
+                            .map_err(|err| anyhow!("{err:?}"))?;
+
+                        anyhow::Ok(())
+                    }
+                    .boxed()
+                }
+            })
+            .await
+    }
+}