Connect store to indexes

storage_engine/src/cursor.rs

@@ -13,7 +13,7 @@ use crate::binary_coding::{encode, decode};
 use crate::entry::{Entry, EntryDetailed};
 use crate::entry_header::{EntryHeaderWithDataSize, EntryHeader};
 use crate::store_header::StoreHeader;
-use crate::storage_engine::{Store, FilePosition, Column, Result, ROWS_FILE_NAME, GARBAGE_COLLECTION_INTERMEDIATE_ROWS_FILE_NAME};
+use crate::storage_engine::{Store, FilePosition, Column, Result, StoreIndexes, ROWS_FILE_NAME, GARBAGE_COLLECTION_INTERMEDIATE_ROWS_FILE_NAME};
 use crate::index::Index;
 
 
@@ -349,7 +349,7 @@ impl <'cursor, T> WriteCursor<'cursor, T>
             Ok(cursor)
     }
 
-    pub async fn connect<'header: 'cursor, 'indexes: 'cursor>(path_to_rows: &str, header: &'header mut StoreHeader, indexes: &'indexes mut Vec<Option<Index<T, FilePosition>>>) -> Result<Self> 
+    pub async fn connect<'header: 'cursor, 'indexes: 'cursor>(path_to_rows: &str, header: &'header mut StoreHeader, indexes: &'indexes mut StoreIndexes<T>) -> Result<Self> 
         where T: Send
     {
             let file: File =

storage_engine/src/index.rs

@@ -1,6 +1,6 @@
 use std::marker::PhantomData;
-use std::path::Path;
+use std::path::PathBuf;
-use tokio::fs::{DirBuilder, File, OpenOptions};
+use tokio::fs::{File, OpenOptions};
 use tokio::io::{AsyncReadExt, AsyncSeekExt, AsyncWriteExt, SeekFrom};
 
 use async_trait::async_trait;
@@ -38,7 +38,7 @@ where
     K: Encode + Decode + Ord,
     V: Encode + Decode + Clone + Eq + Hash,
 {
-    pub async fn new(file_name: &str) -> Result<Index<K, V>> {
+    pub async fn new(file_name: PathBuf) -> Result<Index<K, V>> {
         let file: File = OpenOptions::new()
             .read(true)
             .write(true)
@@ -56,7 +56,7 @@ where
         })
     }
 
-    pub async fn connect(file_name: &str) -> Result<Index<K, V>> {
+    pub async fn connect(file_name: PathBuf) -> Result<Index<K, V>> {
         let mut file: File = OpenOptions::new()
             .read(true)
             .write(true)
@@ -124,7 +124,7 @@ mod tests {
         index.insert("bar".to_string(), 125).await.unwrap();
         index.insert("bar".to_string(), 126).await.unwrap();
 
-        let lookup = index.lookup("foo".to_string()).await.unwrap().unwrap();
+        let lookup = index.lookup(&"foo".to_string()).await.unwrap().unwrap();
         assert_eq!(lookup.len(), 2);
         assert!(lookup.contains(&123));
         assert!(lookup.contains(&124));
@@ -139,7 +139,7 @@ mod tests {
             value_type: PhantomData::<u32>,
         };
 
-        let lookup = decoded.lookup("foo".to_string()).await.unwrap().unwrap();
+        let lookup = decoded.lookup(&"foo".to_string()).await.unwrap().unwrap();
         assert_eq!(lookup.len(), 2);
         assert!(lookup.contains(&123));
         assert!(lookup.contains(&124));

storage_engine/src/storage_engine.rs

@@ -16,27 +16,16 @@ pub type Result<T> = std::result::Result<T, Error>;
 pub type Column = u64;
 pub type FilePosition = u64;
 
-// TODO: Consider introducing a phantom type for the data that's used in the store.
+// TODO: Consider adding another type parameter for indexable values
 #[derive(Debug)]
 pub struct Store<T> {
-    // TODO: This needs to track how many read-write cursors there are...?
-    //   RWMutex
-    //     {write: 0, read: n} ~> {write:0, read: n + 1} // create read
-    //     {write: 0, read: n + 1} ~> {write:0, read: n} // destroy read
-    //     {write: 0, read: 0} ~> {write: 1, read: 0} // create write
-    //     {write: 1, read: 0} ~> {write: 0, read: 0} // destroy write
-    // primary_index: Vec<Index<T, FilePosition>>>,
-    // indexes: Vec<Option<Index<T, HashSet<FilePosition>>>>,
-    // primary_index: Index<PositionOfValue, PositionOfRow>,
-
-    // TODO: It's not good to have StoreHeader copied to all the cursors, since they may modify it.
-    //       How to sync?
-    // All 
     pub header: StoreHeader,
     pub data_type: PhantomData<T>,
-    pub indexes: Vec<Option<Index<T, FilePosition>>>,
+    pub indexes: StoreIndexes<T>,
 }
 
+pub type StoreIndexes<T> = Vec<Option<Index<T, FilePosition>>>;
+
 pub type PositionOfValue = FilePosition;
 pub type PositionOfRow = FilePosition;
 
@@ -75,13 +64,7 @@ impl <T>Store<T> {
         // We don't need the file right now. Only cursors will later open it.
         Self::create_empty_rows_file(path_to_rows, &header).await?;
 
-        // TODO: I need to construct indexes
+        let indexes: StoreIndexes<T> = Self::create_initial_indexes(&header).await?;
-        // let primary_index: Index<T, FilePosition> = Index::new(
-        //     &format!("rows_{}", primary_column.to_string()),
-        // ).await?;
-
-        // TODO
-        let indexes = vec![];
 
         let store = Self {
             header,
@@ -92,6 +75,42 @@ impl <T>Store<T> {
         Ok(store)
     }
 
+    pub fn path_to_index_file(header: &StoreHeader, column: Column) -> PathBuf {
+        let path_to_table = Path::new(&header.table_folder);
+        let path_to_index = path_to_table.join(&format!("{}_{}", ROWS_FILE_NAME, column.to_string()));
+        path_to_index
+    }
+
+    pub async fn create_empty_index_at(header: &StoreHeader, column: Column) -> Result<Index<T, FilePosition>> 
+        where T: Encode + Decode + Ord
+    {
+        let path_to_index = Self::path_to_index_file(&header, column);
+        let index = Index::new(path_to_index).await?;
+
+        Ok(index)
+    }
+
+    pub async fn create_initial_indexes(header: &StoreHeader) -> Result<StoreIndexes<T>> 
+        where T: Encode + Decode + Ord
+    {
+        let mut result: StoreIndexes<T> = Vec::with_capacity(header.number_of_columns);
+        for _ in 0..header.number_of_columns {
+            result.push(None)
+        }
+
+        result[header.primary_column as usize] = Some(Self::create_empty_index_at(&header, header.primary_column).await?);
+
+        Ok(result)
+    }
+
+    pub async fn connect_index_at(header: &StoreHeader, column: Column) -> Result<Index<T, FilePosition>> 
+        where T: Encode + Decode + Ord
+    {
+        let path_to_index = Self::path_to_index_file(&header, column);
+        let index: Index<T, FilePosition> = Index::connect(path_to_index).await?;
+        Ok(index)
+    }
+
     pub async fn create_empty_rows_file(path_to_rows: PathBuf, header: &StoreHeader) -> Result<File> {
         let mut file: File =
             OpenOptions::new()
@@ -134,17 +153,26 @@ impl <T>Store<T> {
         };
 
 
-        // let primary_index: Index<T, FilePosition> = Index::connect(
+        let indexes: StoreIndexes<T> = {
-        //     &format!("rows_{}", header.primary_column.to_string()),
+            let mut result = Vec::with_capacity(header.number_of_columns);
-        // ).await?;
+            for (column, &is_indexed) in header.indexed_columns.iter().enumerate() {
+                if is_indexed {
+                    result.push(None)
+                    // TODO: Once index connect is working, uncomment this line (and remove the
+                    // above .push line
+                    // result.push(Some(Self::connect_index_at(&header, column as Column).await?))
+                } else {
+                    result.push(None)
+                }
+            }
 
-        // TODO
+            result
-        let indexes = vec![];
+        };
 
         let store = Self {
             header,
             data_type: PhantomData::<T>,
-            indexes,
+            indexes
         };
         Ok(store)
     }