add files

squirrel-server/.gitignore

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+/target

squirrel-server/Cargo.lock

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+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 3
+
+[[package]]
+name = "SQUIRREL"
+version = "0.1.0"

squirrel-server/Cargo.toml

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+[package]
+name = "SQUIRREL"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]

squirrel-server/data/tabledefs/users

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+id integer 0 
+name varchar 24 

squirrel-server/src/main.rs

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+use std::thread;
+use std::net::{TcpListener, TcpStream, Shutdown};
+use std::io::{Read, Write};
+use core::str::Split;
+use std::error::Error;
+use std::fs;
+
+mod parser;
+pub use parser::command::Command;
+
+mod table;
+use parser::command::CreateCommand;
+pub use table::datatypes::Datatype;
+pub use table::table::TableDefinition;
+
+const BUFFER_SIZE: usize = 500;
+
+
+/*
+CREATE TABLE [IF NOT EXISTS] table_name (
+   column1 datatype(length) column_contraint,
+   column2 datatype(length) column_contraint,
+   column3 datatype(length) column_contraint,
+   table_constraints
+);
+ */
+fn handle_create(command: CreateCommand) -> Result<TableDefinition, String> {
+    println!("Creating table with name: {}", command.table_definition.name);
+    let mut file = fs::File::create(format!("./data/tabledefs/{}", command.table_definition.name)).unwrap();
+            
+    for column in &command.table_definition.column_defs {
+        println!("creating col: {} {} {}", column.name, column.data_type.as_str(), column.length);
+        let line = format!("{} {} {} \n", column.name, column.data_type.as_str(), column.length);
+        file.write_all(line.as_bytes()).unwrap();
+    }
+
+    return Ok(command.table_definition);
+}
+
+fn run_command(query: String) -> String {
+    let response: String;
+    if query.chars().nth(0).unwrap() == '\\' {
+        // handle PSQL's slash commands e.g.: \dt \d
+        return String::from("Slash commands are not yet supported in SQUIRREL");
+    }
+
+    let command_result: Result<Command, String> = Command::from_string(query);
+
+    if command_result.is_ok() {
+        let command: Command = command_result.unwrap();
+        response = match command {
+            Command::Create(create_command) => { 
+                let result_result = handle_create(create_command); 
+                if result_result.is_err() {
+                    String::from("Error creating table.") 
+                } else {
+                    String::from("Table created.") 
+                }
+            }
+            _ => { String::from("Invalid command") }
+        }
+    } else {
+        response = command_result.err().unwrap();
+    }
+    
+    return response;
+}
+
+fn handle_client(mut stream: TcpStream) {
+    let mut data = [0 as u8; BUFFER_SIZE]; 
+
+    while match stream.read(&mut data) {
+        Ok(size) => {
+            let mut query_string = String::from_utf8(data.to_vec()).expect("A UTF-8 string");
+            println!("Received: {}", query_string);
+
+            let mut i = 0;
+            for c in query_string.chars() {
+                if c == ';' {
+                    query_string = query_string.get(0..i).unwrap().to_string();
+                    i = 0;
+                    break;
+                }
+                i += 1;
+            }
+
+            let response: String;
+            if i == 0 {
+                response = run_command(query_string);
+            } else {
+                response = String::from("No semicolon.");
+            }
+            
+            let mut response_data_size = response.len().to_le_bytes();
+            stream.write(&mut response_data_size).unwrap(); // send length of message
+            stream.write(response.as_bytes()).unwrap(); // send message
+            true
+        },
+        Err(_) => {
+            println!("An error occurred, terminating connection with {}", stream.peer_addr().unwrap());
+            stream.shutdown(Shutdown::Both).unwrap();
+            false
+        }
+    } {}
+}
+
+fn main() -> std::io::Result<()> {
+    fs::remove_dir_all("./data")?; 
+    fs::create_dir("./data")?;
+    fs::create_dir("./data/tabledefs")?;
+    fs::create_dir("./data/blobs")?;
+    let listener = TcpListener::bind("0.0.0.0:5433")?;
+
+    for stream in listener.incoming() {
+        thread::spawn(|| {
+            handle_client(stream.expect("A valid stream"));
+            ()
+        });
+    }
+
+    Ok(())
+}

squirrel-server/src/parser/command.rs

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+use crate::{TableDefinition, Datatype};
+use crate::table::table::Column;
+
+pub enum Command {
+    Select,
+    Create(CreateCommand),
+    Insert,
+    Delete
+}
+
+pub struct CreateCommand {
+    pub table_definition: TableDefinition,
+}
+
+impl Command {
+    pub fn from_string(command_str: String) -> Result<Command, String> {
+        let mut parts = command_str.split(' ');
+
+        match parts.nth(0).unwrap() {
+            "CREATE" => {
+                let object = String::from(parts.nth(0).unwrap());
+                if object.eq_ignore_ascii_case("TABLE") {
+                    let mut column_definitions: Vec<Column> = vec![];
+
+                    let column_def_begin_idx = command_str.chars().position(|c| c == '(').unwrap() + 1;
+                    let column_def_end_idx = command_str.chars().position(|c| c == ')').unwrap();
+                    let coldef_str = command_str.get(column_def_begin_idx..column_def_end_idx).unwrap().to_string();
+                    let col_strs = coldef_str.split(',');
+
+                    for col_str in col_strs {
+                        println!("{}", col_str);
+                        let mut parts = col_str.split_ascii_whitespace();
+                        let mut col: Column = Column {
+                            length: 0,
+                            name: parts.nth(0).unwrap().to_string(),
+                            data_type: Datatype::from_str(parts.nth(0).unwrap()).unwrap()
+                        };
+                        let len = parts.nth(0);
+                        if len.is_some() {
+                            if col.data_type.has_len() {
+                                col.length = len.unwrap().parse().unwrap();
+                            } else {
+                                return Err(format!("ERROR: Datatype '{}' does not accept a length parameter", col.data_type.as_str()));
+                            }
+                        } else if col.data_type.has_len() {
+                            return Err(format!("ERROR: Datatype '{}' requires a length parameter", col.data_type.as_str()));
+                        }
+                        
+                        column_definitions.push(col);
+                    }
+
+                    return Ok(Command::Create(CreateCommand {
+                        table_definition: TableDefinition { 
+                            name: String::from(parts.nth(0).unwrap()),
+                            column_defs: column_definitions
+                        }
+                    }))
+                } else {
+                    return Err(format!("ERROR: syntax error at or near '{}'", object));
+                }
+            },
+            _ => { Err(String::from("Unable to parse command")) }
+        }
+    }
+}

squirrel-server/src/parser/mod.rs

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+pub mod command;

squirrel-server/src/table/datatypes.rs

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+pub enum Datatype {
+    Integer,
+    CharacterVarying,
+}
+
+impl Datatype {
+    pub fn as_str(&self) -> &'static str {
+        match self {
+            Datatype::CharacterVarying => "varchar",
+            Datatype::Integer => "integer"
+        }
+    }
+
+    pub fn has_len(&self) -> bool {
+        match self {
+            Datatype::CharacterVarying => true,
+            Datatype::Integer => false
+        }
+    }
+
+    pub fn from_str(string: &str) -> Result<Datatype, String> {
+        match string {
+            "varchar" => return Ok(Datatype::CharacterVarying),
+            "character varying" => return Ok(Datatype::CharacterVarying),
+            "integer" => return Ok(Datatype::Integer),
+            "int" => return Ok(Datatype::Integer),
+            "int4" => return Ok(Datatype::Integer),
+            _ => {return Err(String::from("Undefined data type"))}
+        }
+    }
+}

squirrel-server/src/table/mod.rs

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+pub mod table;
+pub mod datatypes;

squirrel-server/src/table/table.rs

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+use crate::Datatype;
+
+pub struct Column {
+    pub name: String,
+    pub data_type: Datatype,
+    pub length: u16 // used for char(n), varchar(n)
+}
+
+pub struct TableDefinition {
+    pub name: String,
+    pub column_defs: Vec<Column>,
+}