minisql/minisql/src/interpreter.rs
2024-01-28 18:40:34 +01:00

623 lines
18 KiB
Rust

use crate::schema::{Column, TableName, TableSchema};
use crate::internals::table::Table;
use crate::operation::{Operation, Condition};
use crate::result::DbResult;
use bimap::BiMap;
use serde::{Deserialize, Serialize};
use crate::restricted_row::RestrictedRow;
// Use `TablePosition` as index
pub type Tables = Vec<Table>;
pub type TablePosition = usize;
// ==============Interpreter================
#[derive(Debug, Serialize, Deserialize)]
pub struct State {
table_name_position_mapping: BiMap<TableName, TablePosition>,
tables: Tables,
}
// #[derive(Debug)]
pub enum Response<'a> {
Selected(&'a TableSchema, Box<dyn Iterator<Item=RestrictedRow> + 'a + Send>),
Inserted,
Deleted(usize), // how many were deleted
TableCreated,
IndexCreated,
}
pub type DbSchema<'a> = Vec<(TableName, TablePosition, &'a TableSchema)>;
impl std::fmt::Debug for Response<'_> {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> Result<(), std::fmt::Error> {
use Response::*;
match self {
Selected(_schema, _rows) =>
// TODO: How can we iterate through the rows without having to take ownership of
// them?
f.write_str("Some rows... trust me"),
Inserted =>
f.write_str("Inserted"),
Deleted(usize) =>
f.write_fmt(format_args!("Deleted({})", usize)),
TableCreated =>
f.write_str("TableCreated"),
IndexCreated =>
f.write_str("IndexCreated"),
}
}
}
impl State {
pub fn new() -> Self {
Self {
table_name_position_mapping: BiMap::new(),
tables: vec![],
}
}
pub fn db_schema<'a>(&'a self) -> DbSchema {
let mut schema: DbSchema = Vec::new();
for (table_name, &table_position) in &self.table_name_position_mapping {
let table_schema = self.tables[table_position].schema();
schema.push((table_name.clone(), table_position, table_schema));
}
schema
}
fn table_at<'a>(&'a self, table_position: TablePosition) -> &'a Table {
&self.tables[table_position]
}
fn table_at_mut<'a>(&'a mut self, table_position: TablePosition) -> &'a mut Table {
&mut self.tables[table_position]
}
fn attach_table(&mut self, table: Table) {
let new_table_position: TablePosition = self.tables.len();
self.table_name_position_mapping
.insert(table.schema().table_name().clone(), new_table_position);
self.tables.push(table);
}
pub fn interpret<'a>(&'a mut self, operation: Operation) -> DbResult<Response<'a>> {
// TODO: lock stuff
use Operation::*;
match operation {
Select(table_position, column_selection, maybe_condition) => {
let table: &Table = self.table_at(table_position);
let selected_rows = match maybe_condition {
None => {
let rows = table.select_all_rows(column_selection);
Box::new(rows) as Box<dyn Iterator<Item=RestrictedRow> + 'a + Send>
},
Some(Condition::Eq(eq_column, value)) => {
let x =
table.select_rows_where_eq(
column_selection,
eq_column,
value,
)?;
Box::new(x) as Box<dyn Iterator<Item=RestrictedRow> + 'a + Send>
}
};
Ok(Response::Selected(table.schema(), selected_rows))
},
Insert(table_position, values) => {
let table: &mut Table = self.table_at_mut(table_position);
let (id, row) = table.schema().row_from_insertion_values(values)?;
table.insert_row_at(id, row)?;
Ok(Response::Inserted)
}
Delete(table_position, maybe_condition) => {
let table: &mut Table = self.table_at_mut(table_position);
let rows_affected = match maybe_condition {
None => table.delete_all_rows(),
Some(Condition::Eq(eq_column, value)) => {
table.delete_rows_where_eq(eq_column, value)?
}
};
Ok(Response::Deleted(rows_affected))
}
CreateTable(table_schema) => {
let table = Table::new(table_schema);
self.attach_table(table);
Ok(Response::TableCreated)
}
CreateIndex(table_position, column) => {
let table: &mut Table = self.table_at_mut(table_position);
table.attach_index(column)?;
Ok(Response::IndexCreated)
}
}
}
}
#[cfg(test)]
mod tests {
use super::*;
use crate::schema::Column;
use std::collections::HashSet;
use crate::type_system::{DbType, IndexableValue, Value};
use crate::operation::Operation;
fn users_schema() -> TableSchema {
TableSchema::new(
"users".to_string(),
"id".to_string(),
vec!(
"id".to_string(),
"name".to_string(),
"age".to_string(),
),
vec![DbType::Uuid, DbType::String, DbType::Int],
)
}
#[test]
fn test_table_creation() {
let mut state = State::new();
let users_schema = users_schema();
let users = users_schema.table_name().clone();
state
.interpret(Operation::CreateTable(users_schema))
.unwrap();
assert!(state.tables.len() == 1);
let table = &state.tables[0];
assert!(table.rows().len() == 0);
assert!(table.table_name() == &users);
}
#[test]
fn test_select_empty() {
let mut state = State::new();
let users_schema = users_schema();
let users_position = 0;
state
.interpret(Operation::CreateTable(users_schema.clone()))
.unwrap();
let response: Response = state
.interpret(Operation::Select(users_position, users_schema.all_selection(), None))
.unwrap();
assert!(matches!(response, Response::Selected(_, _)));
let Response::Selected(_schema, rows) = response else {
panic!()
};
let rows: Vec<_> = rows.collect();
assert!(rows.len() == 0);
}
#[test]
fn test_insert_select_basic1() {
use IndexableValue::*;
use Value::*;
let mut state = State::new();
let users_schema = users_schema();
let users = 0;
state
.interpret(Operation::CreateTable(users_schema.clone()))
.unwrap();
let (id, name, age) = (
Indexable(Uuid(0)),
Indexable(String("Plato".to_string())),
Indexable(Int(64)),
);
state
.interpret(Operation::Insert(
users,
vec![
id.clone(),
name.clone(),
age.clone(),
],
))
.unwrap();
let response: Response = state
.interpret(Operation::Select(users, users_schema.all_selection(), None))
.unwrap();
assert!(matches!(response, Response::Selected(_, _)));
let Response::Selected(_schema, rows) = response else {
panic!()
};
let rows: Vec<_> = rows.collect();
assert!(rows.len() == 1);
let row = &rows[0];
assert!(row.len() == 3);
assert!(row[0].1 == id);
assert!(row[1].1 == name);
assert!(row[2].1 == age);
}
#[test]
fn test_insert_select_basic2() {
use Condition::*;
use IndexableValue::*;
use Operation::*;
use Value::*;
let mut state = State::new();
let users_schema = users_schema();
let users_position: TablePosition = 0;
let id_column: Column = 0;
let name_column: Column = 1;
state
.interpret(CreateTable(users_schema.clone()))
.unwrap();
let (id0, name0, age0) = (
Indexable(Uuid(0)),
Indexable(String("Plato".to_string())),
Indexable(Int(64)),
);
state
.interpret(Insert(
users_position,
vec![
id0.clone(),
name0.clone(),
age0.clone(),
],
))
.unwrap();
let (id1, name1, age1) = (
Indexable(Uuid(1)),
Indexable(String("Aristotle".to_string())),
Indexable(Int(20)),
);
state
.interpret(Insert(
users_position,
vec![
id1.clone(),
name1.clone(),
age1.clone(),
],
))
.unwrap();
{
let response: Response = state.interpret(Select(users_position, users_schema.all_selection(), None)).unwrap();
assert!(matches!(response, Response::Selected(_, _)));
let Response::Selected(_, rows) = response else {
panic!()
};
let rows: Vec<_> = rows.collect();
assert!(rows.len() == 2);
let row0 = &rows[0];
let row1 = &rows[1];
assert!(row0.len() == 3);
assert!(row0[0].1 == id0);
assert!(row0[1].1 == name0);
assert!(row0[2].1 == age0);
assert!(row1.len() == 3);
assert!(row1[0].1 == id1);
assert!(row1[1].1 == name1);
assert!(row1[2].1 == age1);
}
{
let response: Response = state
.interpret(Select(
users_position,
users_schema.all_selection(),
Some(Eq(id_column, id0.clone())),
))
.unwrap();
assert!(matches!(response, Response::Selected(_, _)));
let Response::Selected(_, rows) = response else {
panic!()
};
let rows: Vec<_> = rows.collect();
assert!(rows.len() == 1);
let row0 = &rows[0];
assert!(row0.len() == 3);
assert!(row0[0].1 == id0);
assert!(row0[1].1 == name0);
assert!(row0[2].1 == age0);
}
{
let response: Response = state
.interpret(Select(
users_position,
vec![name_column, id_column],
Some(Eq(id_column, id0.clone())),
))
.unwrap();
assert!(matches!(response, Response::Selected(_, _)));
let Response::Selected(_, rows) = response else {
panic!()
};
let rows: Vec<_> = rows.collect();
assert!(rows.len() == 1);
let row0 = &rows[0];
assert!(row0.len() == 2);
assert!(row0[0].1 == name0);
assert!(row0[1].1 == id0);
}
}
#[test]
fn test_delete() {
use Condition::*;
use IndexableValue::*;
use Operation::*;
use Value::*;
let mut state = State::new();
let users_schema = users_schema();
let users_position: TablePosition = 0;
let id_column: Column = 0;
state
.interpret(CreateTable(users_schema.clone()))
.unwrap();
let (id0, name0, age0) = (
Indexable(Uuid(0)),
Indexable(String("Plato".to_string())),
Indexable(Int(64)),
);
state
.interpret(Insert(
users_position,
vec![
id0.clone(),
name0.clone(),
age0.clone(),
],
))
.unwrap();
let (id1, name1, age1) = (
Indexable(Uuid(1)),
Indexable(String("Aristotle".to_string())),
Indexable(Int(20)),
);
state
.interpret(Insert(
users_position,
vec![
id1.clone(),
name1.clone(),
age1.clone(),
],
))
.unwrap();
{
let delete_response: Response = state
.interpret(Delete(
users_position,
Some(Eq(id_column, id0.clone())),
))
.unwrap();
assert!(matches!(delete_response, Response::Deleted(1)));
}
let response: Response = state.interpret(Select(users_position, users_schema.all_selection(), None)).unwrap();
assert!(matches!(response, Response::Selected(_, _)));
let Response::Selected(_, rows) = response else {
panic!()
};
let rows: Vec<_> = rows.collect();
assert!(rows.len() == 1);
let row = &rows[0];
assert!(row.len() == 3);
assert!(row[0].1 == id1);
assert!(row[1].1 == name1);
assert!(row[2].1 == age1);
}
#[test]
fn test_index() {
use IndexableValue::*;
use Operation::*;
use Value::*;
let mut state = State::new();
let users_schema = users_schema();
let users_position: TablePosition = 0;
let name_column: Column = 1;
state
.interpret(CreateTable(users_schema.clone()))
.unwrap();
state
.interpret(CreateIndex(users_position, name_column))
.unwrap();
let (id0, name0, age0) = (
Indexable(Uuid(0)),
Indexable(String("Plato".to_string())),
Indexable(Int(64)),
);
state
.interpret(Insert(
users_position,
vec![
id0.clone(),
name0.clone(),
age0.clone(),
],
))
.unwrap();
let (id1, name1, age1) = (
Indexable(Uuid(1)),
Indexable(String("Aristotle".to_string())),
Indexable(Int(20)),
);
state
.interpret(Insert(
users_position,
vec![
id1.clone(),
name1.clone(),
age1.clone(),
],
))
.unwrap();
assert!(state.tables.len() == 1);
let table = &state.tables[0];
assert!(table.rows().len() == 2);
let user: Column = 1;
assert!(table.indexes().contains_key(&user));
let index = table.indexes().get(&user).unwrap();
let plato_id = 0;
let aristotle_id = 1;
let plato_ids = index.get(&String("Plato".to_string())).cloned().unwrap_or(HashSet::new());
assert!(plato_ids.contains(&plato_id));
assert!(!plato_ids.contains(&aristotle_id));
assert!(plato_ids.len() == 1);
}
}
pub fn example() {
use crate::type_system::{IndexableValue, Value, DbType};
use Condition::*;
use IndexableValue::*;
use Operation::*;
use Value::*;
let id_column: Column = 0;
let name_column: Column = 1;
// let age_column: ColumnPosition = 2;
let users_schema: TableSchema = {
TableSchema::new(
"users".to_string(),
"id".to_string(),
vec!(
"id".to_string(), // 0
"name".to_string(), // 1
"age".to_string(), // 2
),
vec![DbType::Uuid, DbType::String, DbType::Int],
)
};
let users_position: TablePosition = 0;
let mut state = State::new();
state
.interpret(Operation::CreateTable(users_schema.clone()))
.unwrap();
let (id0, name0, age0) = (
Indexable(Uuid(0)),
Indexable(String("Plato".to_string())),
Indexable(Int(64)),
);
println!("==INSERT Plato==");
state
.interpret(Insert(
users_position,
vec![
id0.clone(),
name0.clone(),
age0.clone(),
],
))
.unwrap();
let (id1, name1, age1) = (
Indexable(Uuid(1)),
Indexable(String("Aristotle".to_string())),
Indexable(Int(20)),
);
println!("==INSERT Aristotle==");
state
.interpret(Insert(
users_position,
vec![
id1.clone(),
name1.clone(),
age1.clone(),
],
))
.unwrap();
println!();
{
let response: Response = state
.interpret(Operation::Select(users_position, users_schema.all_selection(), None))
.unwrap();
println!("==SELECT ALL==");
println!("{:?}", response);
println!();
}
{
let response: Response = state
.interpret(Select(
users_position,
users_schema.all_selection(),
Some(Eq(id_column, id0.clone())),
))
.unwrap();
println!("==SELECT Plato==");
println!("{:?}", response);
println!();
}
{
{
// TODO: Why do I have to write these braces explicitely? Why doesn't Rust compiler
// "infer" them?
let _delete_response: Response = state
.interpret(Delete(
users_position,
Some(Eq(id_column, id0.clone())),
))
.unwrap();
println!("==DELETE Plato==");
}
let response: Response = state
.interpret(Select(
users_position,
vec![name_column, id_column],
None,
))
.unwrap();
println!("==SELECT All==");
println!("{:?}", response);
println!();
}
}