issue/230 Add an optional commit message.

Closes #230

src/core/index.rs

@@ -18,6 +18,7 @@ use core::SegmentMeta;
 use super::pool::LeasedItem;
 use std::path::Path;
 use core::IndexMeta;
+use indexer::DirectoryLock;
 use IndexWriter;
 use directory::ManagedDirectory;
 use core::META_FILEPATH;
@@ -118,9 +119,14 @@ impl Index {
     /// The opstamp is the number of documents that have been added
     /// from the beginning of time, and until the moment of the last commit.
     pub fn opstamp(&self) -> u64 {
+        // TODO remove unwrap
         load_metas(self.directory()).unwrap().opstamp
     }
 
+    pub fn load_metas(&self) -> Result<IndexMeta> {
+        load_metas(self.directory())
+    }
+
     /// Open a new index writer. Attempts to acquire a lockfile.
     ///
     /// The lockfile should be deleted on drop, but it is possible
@@ -141,7 +147,8 @@ impl Index {
         num_threads: usize,
         heap_size_in_bytes: usize,
     ) -> Result<IndexWriter> {
-        open_index_writer(self, num_threads, heap_size_in_bytes)
+        let directory_lock = DirectoryLock::lock(self.directory().box_clone())?;
+        open_index_writer(self, num_threads, heap_size_in_bytes, directory_lock)
     }
 
     /// Creates a multithreaded writer

src/core/index_meta.rs

@@ -14,6 +14,8 @@ pub struct IndexMeta {
     pub segments: Vec<SegmentMeta>,
     pub schema: Schema,
     pub opstamp: u64,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub payload: Option<String>,
 }
 
 impl IndexMeta {
@@ -22,6 +24,34 @@ impl IndexMeta {
             segments: vec![],
             schema,
             opstamp: 0u64,
+            payload: None,
         }
     }
 }
+
+
+#[cfg(test)]
+mod tests {
+
+    use serde_json;
+    use super::IndexMeta;
+    use schema::{TEXT, SchemaBuilder};
+
+
+    #[test]
+    fn test_serialize_metas() {
+        let schema = {
+            let mut schema_builder = SchemaBuilder::new();
+            schema_builder.add_text_field("text", TEXT);
+            schema_builder.build()
+        };
+        let index_metas = IndexMeta {
+            segments: Vec::new(),
+            schema: schema,
+            opstamp: 0u64,
+            payload: None
+        };
+        let json = serde_json::ser::to_string(&index_metas).expect("serialization failed");
+        assert_eq!(json, r#"{"segments":[],"schema":[{"name":"text","type":"text","options":{"indexing":{"record":"position","tokenizer":"default"},"stored":false}}],"opstamp":0}"#);
+    }
+}