checkin part 2 solution

Signed-off-by: Alex Chi <iskyzh@gmail.com>

mini-lsm/src/table.rs

@@ -1,3 +1,4 @@
+pub(crate) mod bloom;
 mod builder;
 mod iterator;
 
@@ -13,6 +14,8 @@ pub use iterator::SsTableIterator;
 use crate::block::Block;
 use crate::lsm_storage::BlockCache;
 
+use self::bloom::Bloom;
+
 #[derive(Clone, Debug, PartialEq, Eq)]
 pub struct BlockMeta {
     /// Offset of this data block.
@@ -107,16 +110,20 @@ impl FileObject {
     }
 }
 
+/// An SSTable.
 pub struct SsTable {
-    file: FileObject,
-    block_meta: Vec<BlockMeta>,
-    block_meta_offset: usize,
+    /// The actual storage unit of SsTable, the format is as above.
+    pub(crate) file: FileObject,
+    /// The meta blocks that hold info for data blocks.
+    pub(crate) block_meta: Vec<BlockMeta>,
+    /// The offset that indicates the start point of meta blocks in `file`.
+    pub(crate) block_meta_offset: usize,
     id: usize,
     block_cache: Option<Arc<BlockCache>>,
     first_key: Bytes,
     last_key: Bytes,
+    pub(crate) bloom: Option<Bloom>,
 }
-
 impl SsTable {
     #[cfg(test)]
     pub(crate) fn open_for_test(file: FileObject) -> Result<Self> {
@@ -126,9 +133,13 @@ impl SsTable {
     /// Open SSTable from a file.
     pub fn open(id: usize, block_cache: Option<Arc<BlockCache>>, file: FileObject) -> Result<Self> {
         let len = file.size();
-        let raw_meta_offset = file.read(len - 4, 4)?;
+        let raw_bloom_offset = file.read(len - 4, 4)?;
+        let bloom_offset = (&raw_bloom_offset[..]).get_u32() as u64;
+        let raw_bloom = file.read(bloom_offset, len - 4 - bloom_offset)?;
+        let bloom_filter = Bloom::decode(&raw_bloom);
+        let raw_meta_offset = file.read(bloom_offset - 4, 4)?;
         let block_meta_offset = (&raw_meta_offset[..]).get_u32() as u64;
-        let raw_meta = file.read(block_meta_offset, len - 4 - block_meta_offset)?;
+        let raw_meta = file.read(block_meta_offset, bloom_offset - 4 - block_meta_offset)?;
         let block_meta = BlockMeta::decode_block_meta(&raw_meta[..]);
         Ok(Self {
             file,
@@ -138,6 +149,7 @@ impl SsTable {
             block_meta_offset: block_meta_offset as usize,
             id,
             block_cache,
+            bloom: Some(bloom_filter),
         })
     }
 
@@ -151,6 +163,7 @@ impl SsTable {
             block_cache: None,
             first_key,
             last_key,
+            bloom: None,
         }
     }
 
@@ -207,6 +220,3 @@ impl SsTable {
         self.id
     }
 }
-
-#[cfg(test)]
-mod tests;