Made PrepareCommit public again.

Simplified some of the prepare commit & segment updater code using
async.

src/indexer/index_writer.rs

@@ -605,7 +605,7 @@ impl IndexWriter {
     /// It is also possible to add a payload to the `commit`
     /// using this API.
     /// See [`PreparedCommit::set_payload()`](PreparedCommit.html)
-    pub(crate) fn prepare_commit(&mut self) -> crate::Result<PreparedCommit> {
+    pub fn prepare_commit(&mut self) -> crate::Result<PreparedCommit> {
         // Here, because we join all of the worker threads,
         // all of the segment update for this commit have been
         // sent.

src/indexer/mod.rs

@@ -29,7 +29,7 @@ pub use self::index_writer::IndexWriter;
 pub use self::log_merge_policy::LogMergePolicy;
 pub use self::merge_operation::MergeOperation;
 pub use self::merge_policy::{MergeCandidate, MergePolicy, NoMergePolicy};
-pub(crate) use self::prepared_commit::PreparedCommit;
+pub use self::prepared_commit::PreparedCommit;
 pub use self::segment_entry::SegmentEntry;
 pub use self::segment_manager::SegmentManager;
 pub use self::segment_serializer::SegmentSerializer;

src/indexer/prepared_commit.rs

@@ -3,7 +3,7 @@ use crate::Opstamp;
 use futures::executor::block_on;
 
 /// A prepared commit
-pub(crate) struct PreparedCommit<'a> {
+pub struct PreparedCommit<'a> {
     index_writer: &'a mut IndexWriter,
     payload: Option<String>,
     opstamp: Opstamp,
@@ -18,25 +18,38 @@ impl<'a> PreparedCommit<'a> {
         }
     }
 
-    pub(crate) fn opstamp(&self) -> Opstamp {
+    /// Returns the opstamp associated to the prepared commit.
+    pub fn opstamp(&self) -> Opstamp {
         self.opstamp
     }
 
-    pub(crate) fn set_payload(&mut self, payload: &str) {
+    /// Adds an arbitrary payload to the commit.
+    pub fn set_payload(&mut self, payload: &str) {
         self.payload = Some(payload.to_string())
     }
 
-    pub(crate) fn abort(self) -> crate::Result<Opstamp> {
+    /// Rollbacks any change.
+    pub fn abort(self) -> crate::Result<Opstamp> {
         self.index_writer.rollback()
     }
 
-    pub(crate) fn commit(self) -> crate::Result<Opstamp> {
+    /// Proceeds to commit.
+    /// See `.commit_async()`.
+    pub fn commit(self) -> crate::Result<Opstamp> {
+        block_on(self.commit_async())
+    }
+
+    /// Proceeds to commit.
+    ///
+    /// Unfortunately, contrary to what `PrepareCommit` may suggests,
+    /// this operation is not at all really light.
+    /// At this point deletes have not been flushed yet.
+    pub async fn commit_async(self) -> crate::Result<Opstamp> {
         info!("committing {}", self.opstamp);
-        block_on(
-            self.index_writer
-                .segment_updater()
-                .schedule_commit(self.opstamp, self.payload),
-        )?;
+        self.index_writer
+            .segment_updater()
+            .schedule_commit(self.opstamp, self.payload)
+            .await?;
         Ok(self.opstamp)
     }
 }

src/indexer/segment_updater.rs

@@ -470,7 +470,7 @@ impl SegmentUpdater {
         files
     }
 
-    pub async fn schedule_commit(
+    pub(crate) async fn schedule_commit(
         &self,
         opstamp: Opstamp,
         payload: Option<String>,

src/lib.rs

@@ -174,7 +174,7 @@ pub use crate::indexer::demuxer::*;
 pub use crate::indexer::merge_filtered_segments;
 pub use crate::indexer::merge_indices;
 pub use crate::indexer::operation::UserOperation;
-pub use crate::indexer::IndexWriter;
+pub use crate::indexer::{IndexWriter, PreparedCommit};
 pub use crate::postings::Postings;
 pub use crate::reader::LeasedItem;
 pub use crate::schema::{Document, Term};