Merge branch 'empty-select' into 'main'

Empty select

See merge request x433485/minisql!17

Cargo.lock

@@ -481,6 +481,24 @@ dependencies = [
  "getrandom",
 ]
 
+[[package]]
+name = "rand_pcg"
+version = "0.3.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "59cad018caf63deb318e5a4586d99a24424a364f40f1e5778c29aca23f4fc73e"
+dependencies = [
+ "rand_core",
+]
+
+[[package]]
+name = "rand_seeder"
+version = "0.2.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cf2890aaef0aa82719a50e808de264f9484b74b442e1a3a0e5ee38243ac40bdb"
+dependencies = [
+ "rand_core",
+]
+
 [[package]]
 name = "redox_syscall"
 version = "0.4.1"
@@ -550,6 +568,8 @@ dependencies = [
  "parser",
  "proto",
  "rand",
+ "rand_pcg",
+ "rand_seeder",
  "serde_json",
  "tokio",
 ]

minisql/src/interpreter.rs

@@ -1,6 +1,6 @@
 use crate::schema::{Column, TableName, TablePosition, TableSchema};
 use crate::internals::table::Table;
-use crate::operation::{Operation, Condition};
+use crate::operation::{Operation, Condition, ColumnSelection};
 use crate::result::DbResult;
 use bimap::BiMap;
 use serde::{Deserialize, Serialize};
@@ -18,7 +18,7 @@ pub struct State {
 
 // #[derive(Debug)]
 pub enum Response<'a> {
-    Selected(&'a TableSchema, Box<dyn Iterator<Item=RestrictedRow> + 'a + Send>),
+    Selected(&'a TableSchema, ColumnSelection, Box<dyn Iterator<Item=RestrictedRow> + 'a + Send>),
     Inserted,
     Deleted(usize), // how many were deleted
     TableCreated,
@@ -31,7 +31,7 @@ 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) =>
+            Selected(_schema, _columns, _rows) =>
                 // TODO: How can we iterate through the rows without having to take ownership of
                 // them?
                 f.write_str("Some rows... trust me"),
@@ -89,14 +89,14 @@ impl State {
 
                 let selected_rows = match maybe_condition {
                     None => {
-                        let rows = table.select_all_rows(column_selection);
+                        let rows = table.select_all_rows(column_selection.clone());
                         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,
+                                column_selection.clone(),
                                 eq_column,
                                 value,
                             )?;
@@ -104,7 +104,7 @@ impl State {
                     }
                 };
 
-                Ok(Response::Selected(table.schema(), selected_rows))
+                Ok(Response::Selected(table.schema(), column_selection, selected_rows))
             },
             Insert(table_position, values) => {
                 let table: &mut Table = self.table_at_mut(table_position);
@@ -190,8 +190,8 @@ mod tests {
         let response: Response = state
             .interpret(Operation::Select(users_position, users_schema.all_selection(), None))
             .unwrap();
-        assert!(matches!(response, Response::Selected(_, _)));
+        assert!(matches!(response, Response::Selected(_, _, _)));
-        let Response::Selected(_schema, rows) = response else {
+        let Response::Selected(_, _, rows) = response else {
             panic!()
         };
         let rows: Vec<_> = rows.collect();
@@ -232,8 +232,8 @@ mod tests {
             .interpret(Operation::Select(users, users_schema.all_selection(), None))
             .unwrap();
 
-        assert!(matches!(response, Response::Selected(_, _)));
+        assert!(matches!(response, Response::Selected(_, _, _)));
-        let Response::Selected(_schema, rows) = response else {
+        let Response::Selected(_, _, rows) = response else {
             panic!()
         };
         let rows: Vec<_> = rows.collect();
@@ -299,8 +299,8 @@ mod tests {
         {
             let response: Response = state.interpret(Select(users_position, users_schema.all_selection(), None)).unwrap();
 
-            assert!(matches!(response, Response::Selected(_, _)));
+            assert!(matches!(response, Response::Selected(_, _, _)));
-            let Response::Selected(_, rows) = response else {
+            let Response::Selected(_, _, rows) = response else {
                 panic!()
             };
 
@@ -328,8 +328,8 @@ mod tests {
                     Some(Eq(id_column, id0.clone())),
                 ))
                 .unwrap();
-            assert!(matches!(response, Response::Selected(_, _)));
+            assert!(matches!(response, Response::Selected(_, _, _)));
-            let Response::Selected(_, rows) = response else {
+            let Response::Selected(_, _, rows) = response else {
                 panic!()
             };
             let rows: Vec<_> = rows.collect();
@@ -350,8 +350,8 @@ mod tests {
                     Some(Eq(id_column, id0.clone())),
                 ))
                 .unwrap();
-            assert!(matches!(response, Response::Selected(_, _)));
+            assert!(matches!(response, Response::Selected(_, _, _)));
-            let Response::Selected(_, rows) = response else {
+            let Response::Selected(_, _, rows) = response else {
                 panic!()
             };
             let rows: Vec<_> = rows.collect();
@@ -425,8 +425,8 @@ mod tests {
 
         let response: Response = state.interpret(Select(users_position, users_schema.all_selection(), None)).unwrap();
 
-        assert!(matches!(response, Response::Selected(_, _)));
+        assert!(matches!(response, Response::Selected(_, _, _)));
-        let Response::Selected(_, rows) = response else {
+        let Response::Selected(_, _, rows) = response else {
             panic!()
         };
         let rows: Vec<_> = rows.collect();

minisql/src/type_system.rs

@@ -41,6 +41,23 @@ impl DbType {
         }
     }
 
+    pub fn type_oid(&self) -> i32 {
+        match self {
+            Self::String => 25,
+            Self::Int => 23,
+            Self::Number => 701,
+            Self::Uuid => 2950,
+        }
+    }
+
+    pub fn type_size(&self) -> i16 {
+        match self {
+            Self::String => -2, // null terminated string
+            Self::Int => 8,
+            Self::Number => 8,
+            Self::Uuid => 16,
+        }
+    }
 }
 
 impl Value {
@@ -54,29 +71,6 @@ impl Value {
             },
         }
     }
-
-    pub fn type_oid(&self) -> i32 {
-        match self {
-            Self::Number(_) => 701,
-            Self::Indexable(val) => match val {
-                IndexableValue::String(_) => 25,
-                IndexableValue::Int(_) => 23,
-                IndexableValue::Uuid(_) => 2950,
-            },
-        }
-    }
-
-    pub fn type_size(&self) -> i16 {
-        match self {
-            Self::Number(_) => 8,
-            Self::Indexable(val) => match val {
-                IndexableValue::String(_) => -2, // null terminated string
-                IndexableValue::Int(_) => 8,
-                IndexableValue::Uuid(_) => 16,
-            },
-        }
-    }
-
     pub fn as_text_bytes(&self) -> Vec<u8> {
         match self {
             Self::Number(n) => format!("{n}").into_bytes(),
@@ -123,8 +117,9 @@ mod tests {
     #[test]
     fn test_encode_number() {
         let value = Value::Number(123.456);
-        let oid = value.type_oid();
+        let vtype = value.to_type();
-        let size = value.type_size();
+        let oid = vtype.type_oid();
+        let size = vtype.type_size();
 
         let bytes = value.as_text_bytes();
         let from_bytes = Value::from_text_bytes(&bytes, oid, size).unwrap();
@@ -138,8 +133,9 @@ mod tests {
     #[test]
     fn test_encode_string() {
         let value = Value::Indexable(IndexableValue::String("hello".to_string()));
-        let oid = value.type_oid();
+        let vtype = value.to_type();
-        let size = value.type_size();
+        let oid = vtype.type_oid();
+        let size = vtype.type_size();
 
         let bytes = value.as_text_bytes();
         let from_bytes = Value::from_text_bytes(&bytes, oid, size).unwrap();
@@ -153,8 +149,9 @@ mod tests {
     #[test]
     fn test_encode_string_utf8() {
         let value = Value::Indexable(IndexableValue::String("#速度与激情9 早上好中国 现在我有冰激淋 我很喜欢冰激淋 但是《速度与激情9》比冰激淋 🍧🍦🍨".to_string()));
-        let oid = value.type_oid();
+        let vtype = value.to_type();
-        let size = value.type_size();
+        let oid = vtype.type_oid();
+        let size = vtype.type_size();
 
         let bytes = value.as_text_bytes();
         let from_bytes = Value::from_text_bytes(&bytes, oid, size).unwrap();
@@ -168,8 +165,9 @@ mod tests {
     #[test]
     fn test_encode_int() {
         let value = Value::Indexable(IndexableValue::Int(123));
-        let oid = value.type_oid();
+        let vtype = value.to_type();
-        let size = value.type_size();
+        let oid = vtype.type_oid();
+        let size = vtype.type_size();
 
         let bytes = value.as_text_bytes();
         let from_bytes = Value::from_text_bytes(&bytes, oid, size).unwrap();
@@ -183,8 +181,9 @@ mod tests {
     #[test]
     fn test_encode_uuid() {
         let value = Value::Indexable(IndexableValue::Uuid(123));
-        let oid = value.type_oid();
+        let vtype = value.to_type();
-        let size = value.type_size();
+        let oid = vtype.type_oid();
+        let size = vtype.type_size();
 
         let bytes = value.as_text_bytes();
         let from_bytes = Value::from_text_bytes(&bytes, oid, size).unwrap();
@@ -198,7 +197,8 @@ mod tests {
     #[test]
     fn test_mismatched_size() {
         let value = Value::Indexable(IndexableValue::Uuid(123));
-        let oid = value.type_oid();
+        let vtype = value.to_type();
+        let oid = vtype.type_oid();
         let size = 8;
 
         let bytes = value.as_text_bytes();

server/Cargo.toml

@@ -11,6 +11,8 @@ anyhow = "1.0.76"
 clap = { version = "4.4.18", features = ["derive"] }
 async-trait = "0.1.74"
 rand = "0.8.5"
+rand_seeder = "0.2.3"
+rand_pcg = "0.3.1"
 serde_json = "1.0.112"
 minisql = { path = "../minisql" }
 proto = { path = "../proto" }

server/src/main.rs

@@ -186,10 +186,10 @@ async fn handle_query<W>(writer: &mut W, state: &SharedDbState, query: String, t
                 writer.write_command_complete(CompleteStatus::Insert { oid: 0, rows: 1 }).await?;
                 true
             }
-            Response::Selected(schema, mut rows) => {
+            Response::Selected(schema, columns, mut rows) => {
+                writer.write_table_header(&schema, &columns).await?;
                 match rows.next() {
                     Some(row) => {
-                        writer.write_table_header(&schema, &row).await?;
                         writer.write_table_row(&row).await?;
 
                         let mut sent_rows = 1;

server/src/proto_wrapper.rs

@@ -1,7 +1,10 @@
 use async_trait::async_trait;
+use rand::Rng;
+use rand_pcg::Pcg64;
+use rand_seeder::Seeder;
+use minisql::operation::ColumnSelection;
 use minisql::restricted_row::RestrictedRow;
 use minisql::schema::{Column, TableSchema};
-use minisql::type_system::Value;
 use proto::message::backend::{BackendMessage, ColumnDescription, CommandCompleteData, DataRowData, ErrorResponseData, ReadyForQueryData, RowDescriptionData};
 use proto::message::primitive::pglist::PgList;
 use proto::writer::backend::BackendProtoWriter;
@@ -34,7 +37,7 @@ pub trait ServerProto {
     async fn write_error_message(&mut self, error_message: &str) -> anyhow::Result<()>;
     async fn write_ready_for_query(&mut self) -> anyhow::Result<()>;
     async fn write_empty_query(&mut self) -> anyhow::Result<()>;
-    async fn write_table_header(&mut self, table_schema: &TableSchema, row: &RestrictedRow) -> anyhow::Result<()>;
+    async fn write_table_header(&mut self, table_schema: &TableSchema, columns: &ColumnSelection) -> anyhow::Result<()>;
     async fn write_table_row(&mut self, row: &RestrictedRow) -> anyhow::Result<()>;
     async fn write_command_complete(&mut self, status: CompleteStatus) -> anyhow::Result<()>;
 }
@@ -60,9 +63,9 @@ impl<W> ServerProto for W where W: BackendProtoWriter + Send {
         Ok(())
     }
 
-    async fn write_table_header(&mut self, table_schema: &TableSchema, row: &RestrictedRow) -> anyhow::Result<()> {
+    async fn write_table_header(&mut self, table_schema: &TableSchema, columns: &ColumnSelection) -> anyhow::Result<()> {
-        let columns = row.iter()
+        let columns = columns.iter()
-            .map(|(column, value)| value_to_column_description(table_schema, value, *column))
+            .map(|column| column_to_description(table_schema, *column))
             .collect::<anyhow::Result<Vec<ColumnDescription>>>()?;
 
         self.write_proto(RowDescriptionData { columns: columns.into() }.into()).await?;
@@ -88,13 +91,16 @@ impl<W> ServerProto for W where W: BackendProtoWriter + Send {
     }
 }
 
-fn value_to_column_description(schema: &TableSchema, value: &Value, column: Column) -> anyhow::Result<ColumnDescription> {
+fn column_to_description(schema: &TableSchema, column: Column) -> anyhow::Result<ColumnDescription> {
+    let table_name = schema.table_name();
+    let table_oid = table_name_to_oid(table_name);
+
+    let column_type = schema.column_type(column);
     let name = schema.column_name_from_column(column);
 
-    let table_oid = schema.table_name().as_bytes().as_ptr() as i32;
     let column_index = column.try_into()?;
-    let type_oid = value.type_oid();
+    let type_oid = column_type.type_oid();
-    let type_size = value.type_size();
+    let type_size = column_type.type_size();
 
     Ok(ColumnDescription {
         name: name.to_string().into(),
@@ -106,3 +112,10 @@ fn value_to_column_description(schema: &TableSchema, value: &Value, column: Colu
         format_code: 0, // text format
     })
 }
+
+/// Hashes the table name into single i32 used as a substitute for the table OID
+/// in the PostgreSQL protocol.
+fn table_name_to_oid(table_name: &str) -> i32 {
+    let mut rng: Pcg64 = Seeder::from(table_name).make_rng();
+    rng.gen::<i32>()
+}