Renaming

storage_engine/src/cursor.rs

@@ -13,7 +13,8 @@ use crate::segments::store_header::StoreHeader;
 use crate::store::{Store, FilePosition, Column, Result, ROWS_FILE_NAME, GARBAGE_COLLECTION_INTERMEDIATE_ROWS_FILE_NAME};
 use crate::index::Index;
 use crate::cursor_capabilities::primitive::{CursorCanRead, CursorCanWrite};
-use crate::cursor_capabilities::header_access::{CursorCanReadHeader, CursorCanWriteHeader};
+use crate::cursor_capabilities::traversal::CursorCanTraverse;
+use crate::cursor_capabilities::entry_modification::CursorCanModifyEntries;
 use crate::cursor_capabilities::index_access::{CursorCanWriteToIndex, CursorCanReadIndex};
 
 const GARBAGE_COLLECTION_TRIGGER: usize = 100;
@@ -82,24 +83,24 @@ impl <T>CursorCanWrite<T> for AppendOnlyCursor<T> {}
 
 
 // ===capability to access header===
-impl <T>CursorCanReadHeader<T> for ReadCursor<'_, T> {
+impl <T>CursorCanTraverse<T> for ReadCursor<'_, T> {
     fn header(&self) -> &StoreHeader { &self.header }
 }
 
-impl <T>CursorCanReadHeader<T> for WriteCursor<'_, T> {
+impl <T>CursorCanTraverse<T> for WriteCursor<'_, T> {
     fn header(&self) -> &StoreHeader { &self.header }
 }
 
-impl <T>CursorCanReadHeader<T> for AppendOnlyCursor<T> {
+impl <T>CursorCanTraverse<T> for AppendOnlyCursor<T> {
     fn header(&self) -> &StoreHeader { &self.header }
 }
 
-impl <T>CursorCanWriteHeader<T> for WriteCursor<'_, T> {
+impl <T>CursorCanModifyEntries<T> for WriteCursor<'_, T> {
     fn header_mut(&mut self) -> &mut StoreHeader { self.header }
     fn set_eof_file_position(&mut self, new_file_position: FilePosition) { self.eof_file_position = new_file_position } 
 }
 
-impl <T>CursorCanWriteHeader<T> for AppendOnlyCursor<T> {
+impl <T>CursorCanModifyEntries<T> for AppendOnlyCursor<T> {
     fn header_mut(&mut self) -> &mut StoreHeader { &mut self.header }
     fn set_eof_file_position(&mut self, new_file_position: FilePosition) { self.eof_file_position = new_file_position } 
 }

storage_engine/src/cursor_capabilities/entry_modification.rs

@@ -0,0 +1,67 @@
+use async_trait::async_trait;
+
+use bincode;
+use bincode::Encode;
+use crate::binary_coding::encode;
+
+use crate::segments::entry::Entry;
+use crate::segments::store_header::StoreHeader;
+use crate::store::{FilePosition, Result};
+use crate::cursor_capabilities::primitive::{CursorCanRead, CursorCanWrite};
+use crate::cursor_capabilities::traversal::CursorCanTraverse;
+
+#[async_trait]
+pub trait CursorCanModifyEntries<T>: CursorCanTraverse<T> + CursorCanWrite<T> {
+    fn header_mut(&mut self) -> &mut StoreHeader;
+    fn set_eof_file_position(&mut self, new_file_position: FilePosition);
+
+    // ===Store Header Manipulation===
+    async fn increment_total_count(&mut self) -> Result<()> 
+        where T: Send
+    {
+        self.seek_to_start().await?;
+        self.seek_to(StoreHeader::TOTAL_COUNT_OFFSET as u64).await?;
+        let new_count = self.header_mut().increment_total_count();
+        self.write_bytes(&encode::<usize>(&new_count)?).await?;
+        Ok(())
+    }
+
+    async fn increment_deleted_count(&mut self) -> Result<()> 
+        where T: Send
+    {
+        self.seek_to_start().await?;
+        self.seek_to(StoreHeader::DELETED_COUNT_OFFSET as u64).await?;
+        let new_count = self.header_mut().increment_deleted_count();
+        self.write_bytes(&encode::<usize>(&new_count)?).await?;
+        Ok(())
+    }
+
+    async fn set_header(&mut self, header: &StoreHeader) -> Result<()> 
+        where T: Send
+    {
+        self.seek_to_start().await?;
+        let encoded_header: Vec<u8> = header.encode()?;
+        self.write_bytes(&encoded_header).await?;
+
+        Ok(())
+    }
+
+    // ===Append Entry===
+
+    // Moves cursor to the end.
+    // Returns file position to the start of the new entry.
+    async fn append_entry_no_indexing(&mut self, entry: &Entry<T>) -> Result<FilePosition> 
+        where T: Encode + Send + Sync
+    {
+        self.increment_total_count().await?;
+
+        let encoded_entry: Vec<u8> = entry.encode()?;
+        let file_position = self.seek_to_end().await?;
+        self.write_bytes(&encoded_entry).await?;
+
+        let eof_file_position: FilePosition = self.current_file_position().await?;
+        self.set_eof_file_position(eof_file_position);
+
+        Ok(file_position)
+    }
+}

storage_engine/src/cursor_capabilities/index_access.rs

@@ -9,10 +9,11 @@ use crate::error::Error;
 use crate::segments::entry::{Entry, EntryDetailed};
 use crate::store::{FilePosition, Column, Result};
 use crate::index::Index;
-use crate::cursor_capabilities::header_access::{CursorCanReadHeader, CursorCanWriteHeader};
+use crate::cursor_capabilities::traversal::CursorCanTraverse;
+use crate::cursor_capabilities::entry_modification::CursorCanModifyEntries;
 
 #[async_trait]
-pub trait CursorCanReadIndex<T>: CursorCanReadHeader<T> {
+pub trait CursorCanReadIndex<T>: CursorCanTraverse<T> {
     fn indexes(&mut self) -> &[Option<Index<T, FilePosition>>];
 
     async fn index_lookup(&mut self, column: Column, value: &T) -> Result<Vec<EntryDetailed<T>>> 
@@ -52,7 +53,7 @@ pub trait CursorCanReadIndex<T>: CursorCanReadHeader<T> {
 }
 
 #[async_trait]
-pub trait CursorCanWriteToIndex<T>: CursorCanReadIndex<T> + CursorCanWriteHeader<T> {
+pub trait CursorCanWriteToIndex<T>: CursorCanReadIndex<T> + CursorCanModifyEntries<T> {
     fn indexes_mut(&mut self) -> &mut [Option<Index<T, FilePosition>>];
 
     // Assumes that the column is indexable.

storage_engine/src/cursor_capabilities/mod.rs

@@ -1,3 +1,4 @@
 pub(crate) mod primitive;
-pub(crate) mod header_access;
+pub(crate) mod traversal;
+pub(crate) mod entry_modification;
 pub(crate) mod index_access;

storage_engine/src/cursor_capabilities/traversal.rs

@@ -2,18 +2,19 @@ use tokio::io::AsyncReadExt;
 use async_trait::async_trait;
 
 use bincode;
-use bincode::{Decode, Encode};
-use crate::binary_coding::{encode, decode};
+use bincode::Decode;
+use crate::binary_coding::decode;
 
 use crate::error::{Error, DecodeErrorKind};
-use crate::segments::entry::{Entry, EntryDetailed};
+use crate::segments::entry::EntryDetailed;
 use crate::segments::entry_header::EntryHeaderWithDataSize;
 use crate::segments::store_header::StoreHeader;
 use crate::store::{FilePosition, Column, Result};
-use crate::cursor_capabilities::primitive::{CursorCanRead, CursorCanWrite};
+use crate::cursor_capabilities::primitive::CursorCanRead;
+
 
 #[async_trait]
-pub trait CursorCanReadHeader<T>: CursorCanRead<T> {
+pub trait CursorCanTraverse<T>: CursorCanRead<T> {
     fn header(&self) -> &StoreHeader;
 
     async fn seek_to_start_of_data(&mut self) -> Result<FilePosition> {
@@ -172,59 +173,3 @@ pub trait CursorCanReadHeader<T>: CursorCanRead<T> {
         Ok(bytes)
     }
 }
-
-#[async_trait]
-pub trait CursorCanWriteHeader<T>: CursorCanReadHeader<T> + CursorCanWrite<T> {
-    fn header_mut(&mut self) -> &mut StoreHeader;
-    fn set_eof_file_position(&mut self, new_file_position: FilePosition);
-
-    // ===Store Header Manipulation===
-    async fn increment_total_count(&mut self) -> Result<()> 
-        where T: Send
-    {
-        self.seek_to_start().await?;
-        self.seek_to(StoreHeader::TOTAL_COUNT_OFFSET as u64).await?;
-        let new_count = self.header_mut().increment_total_count();
-        self.write_bytes(&encode::<usize>(&new_count)?).await?;
-        Ok(())
-    }
-
-    async fn increment_deleted_count(&mut self) -> Result<()> 
-        where T: Send
-    {
-        self.seek_to_start().await?;
-        self.seek_to(StoreHeader::DELETED_COUNT_OFFSET as u64).await?;
-        let new_count = self.header_mut().increment_deleted_count();
-        self.write_bytes(&encode::<usize>(&new_count)?).await?;
-        Ok(())
-    }
-
-    async fn set_header(&mut self, header: &StoreHeader) -> Result<()> 
-        where T: Send
-    {
-        self.seek_to_start().await?;
-        let encoded_header: Vec<u8> = header.encode()?;
-        self.write_bytes(&encoded_header).await?;
-
-        Ok(())
-    }
-
-    // ===Append Entry===
-
-    // Moves cursor to the end.
-    // Returns file position to the start of the new entry.
-    async fn append_entry_no_indexing(&mut self, entry: &Entry<T>) -> Result<FilePosition> 
-        where T: Encode + Send + Sync
-    {
-        self.increment_total_count().await?;
-
-        let encoded_entry: Vec<u8> = entry.encode()?;
-        let file_position = self.seek_to_end().await?;
-        self.write_bytes(&encoded_entry).await?;
-
-        let eof_file_position: FilePosition = self.current_file_position().await?;
-        self.set_eof_file_position(eof_file_position);
-
-        Ok(file_position)
-    }
-}

storage_engine/src/store.rs

@@ -6,7 +6,7 @@ use bincode::{Decode, Encode};
 
 use crate::error::Error;
 use crate::cursor::{ReadCursor, WriteCursor};
-use crate::cursor_capabilities::header_access::CursorCanReadHeader;
+use crate::cursor_capabilities::traversal::CursorCanTraverse;
 use crate::segments::store_header::StoreHeader;
 use crate::index::Index;
 
@@ -208,8 +208,8 @@ impl <T>Store<T> {
 mod tests {
     use super::*;
     use crate::segments::entry::Entry;
-    use crate::cursor_capabilities::header_access::CursorCanReadHeader;
     use crate::cursor_capabilities::index_access::{CursorCanWriteToIndex, CursorCanReadIndex};
+    use crate::cursor_capabilities::traversal::CursorCanTraverse;
 
     impl <T>Drop for Store<T> {
         fn drop(&mut self) {