add test for prefix extractor compatibility

test/test.rs

@@ -9,3 +9,4 @@ mod test_compact_range;
 mod test_rocksdb_options;
 mod test_ingest_external_file;
 mod test_slice_transform;
+mod test_prefix_extractor;

test/test_prefix_extractor.rs

+use rocksdb::*;
+use tempdir::TempDir;
+
+struct FixedSuffixTransform {
+    pub suffix_len: usize,
+}
+
+impl SliceTransform for FixedSuffixTransform {
+    fn transform<'a>(&mut self, key: &'a [u8]) -> &'a [u8] {
+        &key[..self.suffix_len]
+    }
+
+    fn in_domain(&mut self, key: &[u8]) -> bool {
+        key.len() >= self.suffix_len
+    }
+}
+
+#[test]
+fn test_prefix_extractor_compatibility() {
+    let path = TempDir::new("_rust_rocksdb_prefix_extractor_compatibility").expect("");
+    let keys = vec![b"k1-0", b"k1-1", b"k1-2", b"k1-3", b"k1-4", b"k1-5", b"k1-6", b"k1-7",
+                    b"k1-8"];
+
+    // create db with no prefix extractor, and insert data
+    {
+        let mut opts = Options::new();
+        opts.create_if_missing(true);
+        let db = DB::open(opts, path.path().to_str().unwrap()).unwrap();
+        let wopts = WriteOptions::new();
+
+        // sst1 with no prefix bloom.
+        db.put_opt(b"k1-0", b"a", &wopts).unwrap();
+        db.put_opt(b"k1-1", b"b", &wopts).unwrap();
+        db.put_opt(b"k1-2", b"c", &wopts).unwrap();
+        db.flush(true /* sync */).unwrap(); // flush memtable to sst file.
+    }
+
+    // open db with prefix extractor, and insert data
+    {
+        let mut bbto = BlockBasedOptions::new();
+        bbto.set_bloom_filter(10, false);
+        bbto.set_whole_key_filtering(false);
+        let mut opts = Options::new();
+        opts.create_if_missing(false);
+        opts.set_block_based_table_factory(&bbto);
+        opts.set_prefix_extractor("FixedSuffixTransform",
+                                  Box::new(FixedSuffixTransform { suffix_len: 2 }))
+            .unwrap();
+        // also create prefix bloom for memtable
+        opts.set_memtable_prefix_bloom_size_ratio(0.1 as f64);
+        let db = DB::open(opts, path.path().to_str().unwrap()).unwrap();
+        let wopts = WriteOptions::new();
+
+        // sst2 with prefix bloom.
+        db.put_opt(b"k1-3", b"a", &wopts).unwrap();
+        db.put_opt(b"k1-4", b"b", &wopts).unwrap();
+        db.put_opt(b"k1-5", b"c", &wopts).unwrap();
+        db.flush(true /* sync */).unwrap(); // flush memtable to sst file.
+
+        // memtable with prefix bloom.
+        db.put_opt(b"k1-6", b"a", &wopts).unwrap();
+        db.put_opt(b"k1-7", b"b", &wopts).unwrap();
+        db.put_opt(b"k1-8", b"c", &wopts).unwrap();
+
+        let mut iter = db.iter();
+        iter.seek(SeekKey::Key(b"k1-0"));
+        let mut key_count = 0;
+        while iter.valid() {
+            // If sst file has no prefix bloom, don't use prefix seek model.
+            assert_eq!(keys[key_count], iter.key());
+            key_count = key_count + 1;
+            iter.next();
+        }
+        assert!(key_count == 9);
+    }
+}