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use crate::common::db::Database;
use crate::common::expr::Expr;
use crate::common::ip;
use std::fmt;
#[derive(Debug)]
pub enum Error {
Empty,
Invalid,
IP(ip::Error),
ExpectedArray(Expr),
ExpectedBlob(Expr),
InvalidArgsCount {
cmd: String,
expected: usize,
actual: usize,
},
}
#[derive(Debug)]
pub enum Query {
Children { ip_block: ip::Block },
Del { ip_block: ip::Block },
Echo { msg: Vec<u8> },
Exists { ip_block: ip::Block },
Get { ip_block: ip::Block },
Info { ip_block: ip::Block },
Parent { ip_block: ip::Block },
Set { ip_block: ip::Block, value: Expr },
}
impl Query {
pub fn from_expr(expr: Expr) -> Result<Self, Error> {
let mut xs = if let Expr::Array(xs) = expr {
xs
} else {
return Err(Error::ExpectedArray(expr));
};
if xs.is_empty() {
return Err(Error::Empty);
}
let cmd_expr = xs.remove(0);
let cmd = if let Expr::Blob(cmd) = cmd_expr {
cmd
} else {
return Err(Error::ExpectedBlob(cmd_expr));
};
match &*cmd {
b"ECHO" => build_echo(xs), // ECHO str
b"SET" => build_set(xs), // SET ::/32 Expr
b"GET" => build_get(xs), // GET ::/32
b"DEL" => build_del(xs), // DEL ::/32
b"EXISTS" => build_exists(xs), // EXISTS ::/32
b"INFO" => build_info(xs), // EXISTS ::/32
b"PARENT" => build_parent(xs), // SUP ::/32
b"CHILDREN" => build_children(xs), // SUB ::/32
_ => Err(Error::Invalid),
}
}
pub fn exec(&self, db: &mut Database) -> Expr {
match self {
Self::Echo { msg } => Expr::Blob(msg.clone()),
Self::Set { ip_block, value: _ } => {
db.set(*ip_block, std::collections::HashMap::new());
Expr::Blob(b"OK".to_vec())
}
Self::Get { ip_block } => db.get(ip_block).map(|x| x.into()).unwrap_or(Expr::Null),
Self::Del { ip_block } => db
.del(ip_block)
.map_or(Expr::Null, |_| Expr::Blob(b"OK".to_vec())),
Self::Exists { ip_block } => Expr::Bool(db.exists(ip_block)),
Self::Info { ip_block } => {
let info: Vec<(&str, String)> = db.info(ip_block).into();
info.into()
}
Self::Parent { ip_block } => {
db.parent(ip_block).map(|x| x.into()).unwrap_or(Expr::Null)
}
Self::Children { ip_block } => db.children(ip_block).into(),
}
}
}
// Display
impl fmt::Display for Query {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
let res = match self {
Query::Set { ip_block, value } => {
format!("SET {} {}", ip_block, value)
}
Query::Get { ip_block } => {
format!("GET {}", ip_block)
}
Query::Echo { msg } => {
format!("ECHO {:?}", String::from_utf8_lossy(msg).into_owned())
}
Query::Del { ip_block } => {
format!("DEL {}", ip_block)
}
Query::Exists { ip_block } => {
format!("EXISTS {}", ip_block)
}
Query::Info { ip_block } => {
format!("INFO {}", ip_block)
}
Query::Parent { ip_block } => {
format!("PARENT {}", ip_block)
}
Query::Children { ip_block } => {
format!("CHILDREN {}", ip_block)
}
};
write!(f, "{}", res)
}
}
impl fmt::Display for Error {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
let res = match self {
Error::Empty => "Received an empty query.".to_string(),
Error::ExpectedArray(got) => format!("Expected an ARRAY, got: {:?}.", got),
Error::ExpectedBlob(got) => format!("Expected a BLOB, got: {:?}.", got),
Error::IP(e) => format!("IP error: {e:?}"),
Error::Invalid => "Received an invalid query.".to_string(),
Error::InvalidArgsCount {
cmd,
expected,
actual,
} => format!(
"Invalid number of arguments for {:?}. Expected {} but got {}.",
cmd, expected, actual
),
};
write!(f, "{}", res)
}
}
// Builders
fn build_echo(mut args: Vec<Expr>) -> Result<Query, Error> {
count_args("ECHO", &args, 1)?;
let expr = args.remove(0);
let msg = if let Expr::Blob(k) = expr {
k
} else {
return Err(Error::ExpectedBlob(expr));
};
Ok(Query::Echo { msg })
}
fn build_get(mut args: Vec<Expr>) -> Result<Query, Error> {
count_args("GET", &args, 1)?;
let expr = args.remove(0);
let ip_block = if let Expr::Blob(ref addr) = expr {
ip::Block::from_bytestring(addr).map_err(Error::IP)?
} else {
return Err(Error::ExpectedBlob(expr));
};
Ok(Query::Get { ip_block })
}
fn build_set(mut args: Vec<Expr>) -> Result<Query, Error> {
count_args("SET", &args, 2)?;
let expr = args.remove(0);
let ip_block = if let Expr::Blob(ref addr) = expr {
ip::Block::from_bytestring(addr).map_err(Error::IP)?
} else {
return Err(Error::ExpectedBlob(expr));
};
Ok(Query::Set {
ip_block,
value: args.remove(0),
})
}
fn build_del(mut args: Vec<Expr>) -> Result<Query, Error> {
count_args("DEL", &args, 1)?;
let expr = args.remove(0);
let ip_block = if let Expr::Blob(ref addr) = expr {
ip::Block::from_bytestring(addr).map_err(Error::IP)?
} else {
return Err(Error::ExpectedBlob(expr));
};
Ok(Query::Del { ip_block })
}
fn build_exists(mut args: Vec<Expr>) -> Result<Query, Error> {
count_args("EXISTS", &args, 1)?;
let expr = args.remove(0);
let ip_block = if let Expr::Blob(ref addr) = expr {
ip::Block::from_bytestring(addr).map_err(Error::IP)?
} else {
return Err(Error::ExpectedBlob(expr));
};
Ok(Query::Exists { ip_block })
}
fn build_info(mut args: Vec<Expr>) -> Result<Query, Error> {
count_args("INFO", &args, 1)?;
let expr = args.remove(0);
let ip_block = if let Expr::Blob(ref addr) = expr {
ip::Block::from_bytestring(addr).map_err(Error::IP)?
} else {
return Err(Error::ExpectedBlob(expr));
};
Ok(Query::Info { ip_block })
}
fn build_parent(mut args: Vec<Expr>) -> Result<Query, Error> {
count_args("PARENT", &args, 1)?;
let expr = args.remove(0);
let ip_block = if let Expr::Blob(ref addr) = expr {
ip::Block::from_bytestring(addr).map_err(Error::IP)?
} else {
return Err(Error::ExpectedBlob(expr));
};
Ok(Query::Parent { ip_block })
}
fn build_children(mut args: Vec<Expr>) -> Result<Query, Error> {
count_args("CHILDREN", &args, 1)?;
let expr = args.remove(0);
let ip_block = if let Expr::Blob(ref addr) = expr {
ip::Block::from_bytestring(addr).map_err(Error::IP)?
} else {
return Err(Error::ExpectedBlob(expr));
};
Ok(Query::Children { ip_block })
}
// Helpers
fn count_args<T>(cmd: &str, args: &Vec<T>, expected_count: usize) -> Result<(), Error> {
let args_count = args.len();
if args_count != expected_count {
return Err(Error::InvalidArgsCount {
cmd: cmd.to_string(),
expected: expected_count,
actual: args_count,
});
}
Ok(())
}
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