Added doc_freq to searcher. Sums the value for all readers.

src/core/searcher.rs

@@ -8,6 +8,7 @@ use std::io;
 use common::TimerTree;
 use postings::Postings;
 use query::Query;
+use schema::Term;
 
 #[derive(Debug)]
 pub struct Searcher {
@@ -30,6 +31,13 @@ impl Searcher {
         segment_reader.doc(doc_id)
     }
 
+    pub fn doc_freq(&self, term: &Term) -> u32 {
+        self.segments
+            .iter()
+            .map(|segment_reader| segment_reader.doc_freq(term))
+            .sum()
+    }
+
     fn add_segment(&mut self, segment: Segment) -> io::Result<()> {
         let segment_reader = try!(SegmentReader::open(segment.clone()));
         self.segments.push(segment_reader);

src/core/segment_reader.rs

@@ -57,6 +57,13 @@ impl SegmentReader {
         
     }
 
+    pub fn doc_freq(&self, term: &Term) -> u32 {
+        match self.get_term_info(term) {
+            Some(term_info) => term_info.doc_freq,
+            None => 0,
+        }
+    }    
+
     pub fn get_store_reader(&self) -> &StoreReader {
         &self.store_reader
     }

src/lib.rs

@@ -2,6 +2,7 @@
 #![cfg_attr(test, feature(test))]
 #![cfg_attr(test, feature(step_by))]
 #![doc(test(attr(allow(unused_variables), deny(warnings))))]
+#![feature(iter_arith)]
 
 
 #[macro_use]
@@ -106,9 +107,54 @@ mod tests {
 
     }
 
-
     #[test]
     fn test_docfreq() {
+        let mut schema = schema::Schema::new();
+        let text_field = schema.add_text_field("text", schema::TEXT);
+        let index = Index::create_in_ram(schema);
+        {
+            let mut index_writer = index.writer_with_num_threads(1).unwrap();
+            let mut doc = Document::new();
+            doc.add_text(text_field, "a b c");
+            index_writer.add_document(doc).unwrap();
+            index_writer.wait().unwrap();
+        }
+        {
+            let mut index_writer = index.writer_with_num_threads(1).unwrap();
+            {
+                let mut doc = Document::new();
+                doc.add_text(text_field, "a");
+                index_writer.add_document(doc).unwrap();
+            }
+            {
+                let mut doc = Document::new();
+                doc.add_text(text_field, "a a");
+                index_writer.add_document(doc).unwrap();
+            }
+            index_writer.wait().unwrap();
+        }
+        {
+            let mut index_writer = index.writer_with_num_threads(1).unwrap();
+            let mut doc = Document::new();
+            doc.add_text(text_field, "c");
+            index_writer.add_document(doc).unwrap();
+            index_writer.wait().unwrap();
+        }
+        {
+            let searcher = index.searcher().unwrap();
+            let term_a = Term::from_field_text(text_field, "a");
+            assert_eq!(searcher.doc_freq(&term_a), 3);
+            let term_b = Term::from_field_text(text_field, "b");
+            assert_eq!(searcher.doc_freq(&term_b), 1);
+            let term_c = Term::from_field_text(text_field, "c");
+            assert_eq!(searcher.doc_freq(&term_c), 2);
+            let term_d = Term::from_field_text(text_field, "d");
+            assert_eq!(searcher.doc_freq(&term_d), 0);            
+        }
+    }
+
+    #[test]
+    fn test_termfreq() {
         let mut schema = schema::Schema::new();
         let text_field = schema.add_text_field("text", schema::TEXT);
         let index = Index::create_in_ram(schema);