more comments, sync check

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

mini-lsm-starter/src/block/builder.rs

@@ -3,26 +3,27 @@
 
 use super::Block;
 
-/// Builds a block
+/// Builds a block.
 pub struct BlockBuilder {}
 
 impl BlockBuilder {
-    /// Creates a new block builder
-    pub fn new(target_size: usize) -> Self {
+    /// Creates a new block builder.
+    pub fn new(block_size: usize) -> Self {
         unimplemented!()
     }
 
-    /// Adds a key-value pair to the block
+    /// Adds a key-value pair to the block. Returns false when the block is full.
     #[must_use]
     pub fn add(&mut self, key: &[u8], value: &[u8]) -> bool {
         unimplemented!()
     }
 
+    /// Check if there is no key-value pair in the block.
     pub fn is_empty(&self) -> bool {
         unimplemented!()
     }
 
-    /// Builds a block
+    /// Finalize the block.
     pub fn build(self) -> Block {
         unimplemented!()
     }

mini-lsm-starter/src/block/iterator.rs

@@ -5,57 +5,60 @@ use std::sync::Arc;
 
 use super::Block;
 
-pub struct BlockIterator {}
+/// Iterates on a block.
+pub struct BlockIterator {
+    block: Arc<Block>,
+    key: Vec<u8>,
+    value: Vec<u8>,
+    idx: usize,
+}
 
 impl BlockIterator {
     fn new(block: Arc<Block>) -> Self {
-        unimplemented!()
+        Self {
+            block,
+            key: Vec::new(),
+            value: Vec::new(),
+            idx: 0,
+        }
     }
 
+    /// Creates a block iterator and seek to the first entry.
     pub fn create_and_seek_to_first(block: Arc<Block>) -> Self {
         unimplemented!()
     }
 
+    /// Creates a block iterator and seek to the first key that >= `key`.
     pub fn create_and_seek_to_key(block: Arc<Block>, key: &[u8]) -> Self {
         unimplemented!()
     }
 
+    /// Returns the key of the current entry.
     pub fn key(&self) -> &[u8] {
         unimplemented!()
     }
 
+    /// Returns the value of the current entry.
     pub fn value(&self) -> &[u8] {
         unimplemented!()
     }
 
+    /// Returns true if the iterator is valid.
     pub fn is_valid(&self) -> bool {
         unimplemented!()
     }
 
+    /// Seeks to the first key in the block.
     pub fn seek_to_first(&mut self) {
         unimplemented!()
     }
 
-    pub fn seek_to_last(&mut self) {
-        unimplemented!()
-    }
-
-    pub fn len(&self) -> usize {
-        unimplemented!()
-    }
-
-    pub fn is_empty(&self) -> bool {
-        unimplemented!()
-    }
-
-    pub fn seek_to(&mut self, idx: usize) {
-        unimplemented!()
-    }
-
+    /// Move to the next key in the block.
     pub fn next(&mut self) {
         unimplemented!()
     }
 
+    /// Seek to the first key that >= `key`.
     pub fn seek_to_key(&mut self, key: &[u8]) {
         unimplemented!()
     }

mini-lsm-starter/src/lib.rs

@@ -1,2 +1,3 @@
 pub mod block;
+pub mod storage;
 pub mod table;

mini-lsm-starter/src/storage.rs

@@ -0,0 +1 @@
+pub struct Storage {}

mini-lsm-starter/src/table.rs

@@ -1 +1,85 @@
+#![allow(unused_variables)] // TODO(you): remove this lint after implementing this mod
+#![allow(dead_code)] // TODO(you): remove this lint after implementing this mod
 
+mod builder;
+mod iterator;
+
+use std::{path::Path, sync::Arc};
+
+pub use builder::SsTableBuilder;
+use bytes::{Buf, Bytes};
+pub use iterator::SsTableIterator;
+
+use crate::block::Block;
+use anyhow::Result;
+
+#[derive(Clone, Debug, PartialEq, Eq)]
+pub struct BlockMeta {
+    /// Offset of this data block.
+    pub offset: usize,
+    /// The first key of the data block.
+    pub first_key: Bytes,
+}
+
+impl BlockMeta {
+    /// Encode block meta to a buffer.
+    pub fn encode_block_meta(
+        block_meta: &[BlockMeta],
+        #[allow(clippy::ptr_arg)] buf: &mut Vec<u8>,
+    ) {
+        unimplemented!()
+    }
+
+    /// Decode block meta from a buffer.
+    pub fn decode_block_meta(buf: impl Buf) -> Vec<BlockMeta> {
+        unimplemented!()
+    }
+}
+
+/// A file object.
+pub struct FileObject(Bytes);
+
+impl FileObject {
+    pub fn read(&self, offset: u64, len: u64) -> Result<Vec<u8>> {
+        Ok(self.0[offset as usize..(offset + len) as usize].to_vec())
+    }
+
+    pub fn size(&self) -> u64 {
+        self.0.len() as u64
+    }
+
+    pub fn create(path: &Path, data: Vec<u8>) -> Result<Self> {
+        unimplemented!()
+    }
+
+    pub fn open(path: &Path) -> Result<Self> {
+        unimplemented!()
+    }
+}
+
+pub struct SsTable {}
+
+impl SsTable {
+    /// Open SSTable from a file.
+    pub fn open(file: FileObject) -> Result<Self> {
+        unimplemented!()
+    }
+
+    /// Read a block from the disk.
+    pub fn read_block(&self, block_idx: usize) -> Result<Arc<Block>> {
+        unimplemented!()
+    }
+
+    /// Find the block that may contain `key`.
+    pub fn find_block_idx(&self, key: &[u8]) -> usize {
+        unimplemented!()
+    }
+
+    /// Get number of data blocks.
+    pub fn num_of_blocks(&self) -> usize {
+        unimplemented!()
+    }
+}
+
+#[cfg(test)]
+mod tests;

mini-lsm-starter/src/table/builder.rs

@@ -0,0 +1,30 @@
+#![allow(unused_variables)] // TODO(you): remove this lint after implementing this mod
+#![allow(dead_code)] // TODO(you): remove this lint after implementing this mod
+
+use anyhow::Result;
+use std::path::Path;
+
+use super::{BlockMeta, SsTable};
+
+/// Builds an SSTable from key-value pairs.
+pub struct SsTableBuilder {
+    pub(super) meta: Vec<BlockMeta>,
+}
+
+impl SsTableBuilder {
+    /// Create a builder based on target SST size and target block size.
+    pub fn new(target_size: usize, block_size: usize) -> Self {
+        unimplemented!()
+    }
+
+    /// Adds a key-value pair to SSTable, return false when SST full.
+    #[must_use]
+    pub fn add(&mut self, key: &[u8], value: &[u8]) -> bool {
+        unimplemented!()
+    }
+
+    /// Builds the SSTable and writes it to the given path. No need to actually write to disk until chapter 4 block cache.
+    pub fn build(self, path: impl AsRef<Path>) -> Result<SsTable> {
+        unimplemented!()
+    }
+}

mini-lsm-starter/src/table/iterator.rs

@@ -0,0 +1,53 @@
+#![allow(unused_variables)] // TODO(you): remove this lint after implementing this mod
+#![allow(dead_code)] // TODO(you): remove this lint after implementing this mod
+
+use anyhow::Result;
+use std::sync::Arc;
+
+use super::SsTable;
+
+/// An iterator over the contents of an SSTable.
+pub struct SsTableIterator {}
+
+impl SsTableIterator {
+    /// Create a new iterator and seek to the first key-value pair.
+    pub fn create_and_seek_to_first(table: Arc<SsTable>) -> Result<Self> {
+        unimplemented!()
+    }
+
+    /// Seek to the first key-value pair.
+    pub fn seek_to_first(&mut self) -> Result<()> {
+        unimplemented!()
+    }
+
+    /// Create a new iterator and seek to the first key-value pair which >= `key`.
+    pub fn create_and_seek_to_key(table: Arc<SsTable>, key: &[u8]) -> Result<Self> {
+        unimplemented!()
+    }
+
+    /// Seek to the first key-value pair which >= `key`.
+    pub fn seek_to_key(&mut self, key: &[u8]) -> Result<()> {
+        unimplemented!()
+    }
+
+    /// Get the current key.
+    pub fn key(&self) -> &[u8] {
+        unimplemented!()
+    }
+
+    /// Get the current value.
+    pub fn value(&self) -> &[u8] {
+        unimplemented!()
+    }
+
+    /// Check if the iterator is valid.
+    pub fn is_valid(&self) -> bool {
+        unimplemented!()
+    }
+
+    /// Move to the next key-value pair.
+    #[allow(clippy::should_implement_trait)]
+    pub fn next(&mut self) -> Result<()> {
+        unimplemented!()
+    }
+}

mini-lsm-starter/src/table/tests.rs

@@ -0,0 +1 @@
+