Merge branch 'interpreter2-misc' into 'interpreter-to-storage-engine'

Misc 2: Electring Boogaloo **Cancellation Token**

See merge request x433485/minisql!36

minisql/src/cancellation.rs

@@ -0,0 +1,13 @@
+pub trait Cancellation {
+    fn is_canceled(&self) -> bool;
+}
+
+#[cfg(test)]
+pub(crate) struct DummyCancellation;
+
+#[cfg(test)]
+impl Cancellation for DummyCancellation {
+    fn is_canceled(&self) -> bool {
+        false
+    }
+}

minisql/src/interpreter2.rs

@@ -19,6 +19,7 @@ use storage_engine::segments::entry::Entry;
 use storage_engine::cursor::{ReadCursor, WriteCursor};
 use storage_engine::cursor_capabilities::traversal::CursorCanTraverse;
 use storage_engine::cursor_capabilities::index_access::{CursorCanReadIndex, CursorCanWriteToIndex};
+use crate::cancellation::Cancellation;
 
 const METADATA_FILE: &'static str = "metadata.json";
 
@@ -135,25 +136,39 @@ impl State {
         self.tables.push(RwLock::new(table));
     }
 
-    async fn select_all_rows<Writer: ResponseWriter>(table: &Table, mut cursor: ReadCursor<'_, Value>, response_writer: &mut Writer, column_selection: ColumnSelection) -> DbResult<usize> {
+    async fn select_all_rows<W, C>(table: &Table, mut cursor: ReadCursor<'_, Value>, response_writer: &mut W, cancellation: &C, column_selection: ColumnSelection) -> DbResult<usize>
+    where W: ResponseWriter,
+          C: Cancellation
+    {
         let mut count = 0;
         while let Some(entry) = cursor.next_alive().await.map_err(|e| RuntimeError::StorageEngineError(table.table_name().to_string(), e))? {
             count += 1;
             let row: Row = From::from(entry);
             let restricted_row = row.restrict_columns(&column_selection);
             response_writer.write_table_row(&restricted_row).await.map_err(|e| RuntimeError::AnyhowError(e))?;
+
+            if cancellation.is_canceled() {
+                break;
+            }
         }
 
         Ok(count)
     }
 
-    async fn select_eq<Writer: ResponseWriter>(table: &Table, mut cursor: ReadCursor<'_, Value>, response_writer: &mut Writer, column_selection: ColumnSelection, column: Column, value: Value) -> DbResult<usize> {
+    async fn select_eq<W, C>(table: &Table, mut cursor: ReadCursor<'_, Value>, response_writer: &mut W, cancellation: &C, column_selection: ColumnSelection, column: Column, value: Value) -> DbResult<usize>
+    where W: ResponseWriter,
+          C: Cancellation
+    {
         let entries = cursor.select_entries_where_eq(column as storage_engine::store::Column, &value).await.map_err(|e| RuntimeError::StorageEngineError(table.table_name().to_string(), e))?;
         let count = entries.len();
         for entry in entries {
             let row: Row = From::from(entry);
             let restricted_row = row.restrict_columns(&column_selection);
             response_writer.write_table_row(&restricted_row).await.map_err(|e| RuntimeError::AnyhowError(e))?;
+
+            if cancellation.is_canceled() {
+                break;
+            }
         }
 
         Ok(count)
@@ -218,7 +233,7 @@ impl StateHandler {
         self.state.read().await
     }
 
-    pub async fn interpret<Writer: ResponseWriter>(&self, response_writer: &mut Writer, operation: Operation) -> DbResult<()> {
+    pub async fn interpret<W: ResponseWriter, C: Cancellation>(&self, response_writer: &mut W, cancellation: &C, operation: Operation) -> DbResult<()> {
         use Operation::*;
 
         match operation {
@@ -230,8 +245,8 @@ impl StateHandler {
 
                 response_writer.write_table_header(&table.schema, &column_selection).await.map_err(|e| RuntimeError::AnyhowError(e))?;
                 let count = match maybe_condition {
-                    None => State::select_all_rows(&table, cursor, response_writer, column_selection).await?,
+                    None => State::select_all_rows(&table, cursor, response_writer, cancellation, column_selection).await?,
-                    Some(Condition::Eq(eq_column, value)) => State::select_eq(&table, cursor, response_writer, column_selection, eq_column, value).await?
+                    Some(Condition::Eq(eq_column, value)) => State::select_eq(&table, cursor, response_writer, cancellation, column_selection, eq_column, value).await?
                 };
                 response_writer.write_command_complete(CompleteStatus::Select(count)).await.map_err(|e| RuntimeError::AnyhowError(e))
             }
@@ -290,6 +305,8 @@ mod tests {
     use crate::type_system::{DbType, IndexableValue, Value};
     use std::collections::HashSet;
     use tokio::fs::{File, OpenOptions, DirBuilder};
+    use tokio::fs;
+    use crate::cancellation::DummyCancellation;
 
     impl Drop for State {
         fn drop(&mut self) {
@@ -321,14 +338,14 @@ mod tests {
         let mut response_writer = ResponseWriterStub::new();
 
         state
-            .interpret(&mut response_writer, Operation::CreateTable(users_schema.clone())).await
+            .interpret(&mut response_writer, &DummyCancellation, Operation::CreateTable(users_schema.clone())).await
             .unwrap();
 
         {
             println!("==EMPTY SELECT===");
             let users_position: TablePosition = 0;
             state
-                .interpret(&mut response_writer, Operation::Select(
+                .interpret(&mut response_writer, &DummyCancellation, Operation::Select(
                     users_position,
                     users_schema.all_selection(),
                     None,
@@ -347,7 +364,7 @@ mod tests {
             println!("About to insert!");
 
             state
-                .interpret(&mut response_writer, Operation::Insert(
+                .interpret(&mut response_writer, &DummyCancellation, Operation::Insert(
                     users,
                     vec![id.clone(), name.clone(), age.clone()],
                 )).await
@@ -357,7 +374,7 @@ mod tests {
             println!("==SELECT===");
             let users_position: TablePosition = 0;
             state
-                .interpret(&mut response_writer, Operation::Select(
+                .interpret(&mut response_writer, &DummyCancellation, Operation::Select(
                     users_position,
                     users_schema.all_selection(),
                     None,

minisql/src/lib.rs

@@ -8,3 +8,4 @@ pub mod restricted_row;
 mod result;
 pub mod schema;
 pub mod type_system;
+pub mod cancellation;

server/src/cancellation.rs

@@ -1,5 +1,6 @@
 use std::sync::atomic::{AtomicBool, Ordering};
 use std::sync::Arc;
+use minisql::cancellation::Cancellation;
 
 pub struct ResetCancelToken {
     is_canceled: Arc<AtomicBool>,
@@ -12,10 +13,6 @@ impl ResetCancelToken {
         }
     }
 
-    pub fn is_canceled(&self) -> bool {
-        self.is_canceled.load(Ordering::SeqCst)
-    }
-
     pub fn cancel(&self) {
         self.is_canceled.store(true, Ordering::SeqCst);
     }
@@ -25,6 +22,12 @@ impl ResetCancelToken {
     }
 }
 
+impl Cancellation for ResetCancelToken {
+    fn is_canceled(&self) -> bool {
+        self.is_canceled.load(Ordering::SeqCst)
+    }
+}
+
 impl Clone for ResetCancelToken {
     fn clone(&self) -> Self {
         Self {

server/src/main.rs

@@ -189,7 +189,6 @@ where
         parse_and_validate(query, &db_schema)?
     };
 
-    //  TODO: PASS DOWN RESET CANCEL TOKEN
+    state.interpret(writer, token, operation).await?;
-    state.interpret(writer, operation).await?;
     Ok(())
 }