mod functions;
mod literals;
use anyhow::{Context, Result, bail, ensure};
use full_moon::{
ast::{BinOp, Call, Expression, FunctionArgs, LastStmt, LuaVersion, Prefix, Suffix, UnOp, Var},
tokenizer::{Lexer, LexerResult, Symbol, TokenType},
};
use rusqlite::types::Value;
pub struct CompiledFilter {
sql: String,
params: Vec<Value>,
}
impl CompiledFilter {
pub fn sql(&self) -> &str {
&self.sql
}
pub fn params(&self) -> &[Value] {
&self.params
}
}
#[derive(Clone, Copy, Debug, PartialEq, Eq)]
enum Kind {
Boolean,
Number,
Text,
Nil,
}
struct Expr {
sql: String,
kind: Kind,
}
fn compatible(left: Kind, right: Kind) -> Result<Kind> {
ensure!(
left == right || left == Kind::Nil || right == Kind::Nil,
"incompatible value types {left:?} and {right:?}"
);
Ok(if left == Kind::Nil { right } else { left })
}
fn truthy(value: &Expr) -> String {
match value.kind {
Kind::Boolean => format!("COALESCE(({}),0)", value.sql),
Kind::Nil | Kind::Number | Kind::Text => format!("({}) IS NOT NULL", value.sql),
}
}
fn require(value: &Expr, kind: Kind) -> Result<()> {
ensure!(
value.kind == kind || value.kind == Kind::Nil,
"expected {kind:?}, got {:?}",
value.kind
);
Ok(())
}
pub fn compile(source: &str) -> Result<CompiledFilter> {
compile_inner(source)
.map_err(|error| anyhow::anyhow!("Invalid --filter: {error:#}. See docs/filter.md"))
}
fn compile_inner(source: &str) -> Result<CompiledFilter> {
ensure!(!source.trim().is_empty(), "expression is empty");
ensure!(source.len() <= 16_384, "expression exceeds 16 KiB");
let tokens = match Lexer::new(source, LuaVersion::luau()).collect() {
LexerResult::Ok(tokens) => tokens,
LexerResult::Fatal(errors) | LexerResult::Recovered(_, errors) => {
bail!(
"invalid Luau syntax: {}",
errors.first().context("lexer failed")?
)
}
};
ensure!(
tokens
.iter()
.filter(|token| !token.token_type().is_trivia()
&& !matches!(token.token_type(), TokenType::Eof))
.count()
<= 128,
"expression exceeds 128 tokens"
);
let wrapped = format!("return (\n{source}\n)");
let ast = full_moon::parse_fallible(&wrapped, LuaVersion::luau())
.into_result()
.map_err(|errors| {
anyhow::anyhow!(
"invalid Luau syntax: {}",
errors.first().map(ToString::to_string).unwrap_or_default()
)
})?;
ensure!(
ast.nodes().stmts().next().is_none(),
"only one expression is allowed"
);
let Some(LastStmt::Return(returned)) = ast.nodes().last_stmt() else {
bail!("only one expression is allowed")
};
let mut expressions = returned.returns().iter();
let expression = expressions.next().context("expression is missing")?;
ensure!(
expressions.next().is_none(),
"only one expression is allowed"
);
let mut compiler = Compiler {
params: Vec::new(),
nodes: 0,
};
let result = compiler.expression(expression, 0)?;
let sql = truthy(&result);
ensure!(
sql.len() <= 65_536,
"compiled expression exceeds 64 KiB SQL"
);
Ok(CompiledFilter {
sql,
params: compiler.params,
})
}
struct Compiler {
params: Vec<Value>,
nodes: usize,
}
impl Compiler {
fn literal(&mut self, value: Value, kind: Kind) -> Expr {
self.params.push(value);
Expr {
sql: format!("?{}", self.params.len()),
kind,
}
}
fn expression(&mut self, expression: &Expression, depth: usize) -> Result<Expr> {
ensure!(depth <= 32, "expression exceeds 32 AST levels");
self.nodes += 1;
ensure!(self.nodes <= 128, "expression exceeds 128 AST nodes");
let next = depth + 1;
let result = match expression {
Expression::Parentheses { expression, .. } => self.expression(expression, next)?,
Expression::Number(token) => {
let TokenType::Number { text } = token.token_type() else {
bail!("invalid number")
};
self.literal(literals::number(text.as_str())?, Kind::Number)
}
Expression::String(token) => {
let TokenType::StringLiteral {
literal,
quote_type,
..
} = token.token_type()
else {
bail!("invalid string")
};
self.literal(
Value::Text(literals::string(literal.as_str(), *quote_type)?),
Kind::Text,
)
}
Expression::Symbol(token) => match token.token_type() {
TokenType::Symbol {
symbol: Symbol::True,
} => self.literal(Value::Integer(1), Kind::Boolean),
TokenType::Symbol {
symbol: Symbol::False,
} => self.literal(Value::Integer(0), Kind::Boolean),
TokenType::Symbol {
symbol: Symbol::Nil,
} => self.literal(Value::Null, Kind::Nil),
_ => bail!("unsupported literal"),
},
Expression::Var(Var::Name(token)) => {
let TokenType::Identifier { identifier } = token.token_type() else {
bail!("invalid variable")
};
variable(identifier.as_str())?
}
Expression::UnaryOperator { unop, expression } => {
let value = self.expression(expression, next)?;
match unop {
UnOp::Not(_) => Expr {
sql: format!("NOT ({})", truthy(&value)),
kind: Kind::Boolean,
},
UnOp::Minus(_) => {
require(&value, Kind::Number)?;
Expr {
sql: format!("-({})", value.sql),
kind: Kind::Number,
}
}
UnOp::Hash(_) => {
require(&value, Kind::Text)?;
Expr {
sql: format!("length(CAST(({}) AS BLOB))", value.sql),
kind: Kind::Number,
}
}
_ => bail!("unsupported unary operator"),
}
}
Expression::BinaryOperator { lhs, binop, rhs } => {
let left = self.expression(lhs, next)?;
let right = self.expression(rhs, next)?;
binary(left, binop, right)?
}
Expression::FunctionCall(call) => {
let Prefix::Name(token) = call.prefix() else {
bail!("only named SQLite functions are allowed")
};
let TokenType::Identifier { identifier } = token.token_type() else {
bail!("invalid function name")
};
let mut suffixes = call.suffixes();
let Some(Suffix::Call(Call::AnonymousCall(args))) = suffixes.next() else {
bail!("method/member calls are unavailable")
};
ensure!(
suffixes.next().is_none(),
"chained/member calls are unavailable"
);
let FunctionArgs::Parentheses { arguments, .. } = args.as_ref() else {
bail!("functions require parenthesized arguments")
};
let args = arguments
.iter()
.map(|arg| self.expression(arg, next))
.collect::<Result<Vec<_>>>()?;
functions::compile(identifier.as_str(), args)?
}
Expression::IfExpression(value) => {
ensure!(value.binding().is_none(), "if bindings are unavailable");
let condition = self.expression(value.condition(), next)?;
let then_value = self.expression(value.if_expression(), next)?;
let mut kind = then_value.kind;
let mut sql = format!(
"CASE WHEN ({}) THEN ({})",
truthy(&condition),
then_value.sql
);
for branch in value.else_if_expressions().into_iter().flatten() {
ensure!(branch.binding().is_none(), "if bindings are unavailable");
let condition = self.expression(branch.condition(), next)?;
let value = self.expression(branch.expression(), next)?;
kind = compatible(kind, value.kind)?;
sql.push_str(&format!(
" WHEN ({}) THEN ({})",
truthy(&condition),
value.sql
));
}
let else_value = self.expression(value.else_expression(), next)?;
kind = compatible(kind, else_value.kind)?;
sql.push_str(&format!(" ELSE ({}) END", else_value.sql));
Expr { sql, kind }
}
_ => bail!(
"unsupported Luau expression; use documented task variables, operators, and functions"
),
};
ensure!(
result.sql.len() <= 65_536,
"compiled expression exceeds 64 KiB SQL"
);
Ok(result)
}
}
fn variable(name: &str) -> Result<Expr> {
let (column, kind) = match name {
"id" => ("id", Kind::Number),
"priority" => ("priority", Kind::Number),
"parent_id" => ("parent_id", Kind::Number),
"archived" => ("archived", Kind::Boolean),
"description" | "task_name" => ("description", Kind::Text),
"created_at" | "created_time" => ("created_at", Kind::Text),
"updated_at" | "updated_time" => ("updated_at", Kind::Text),
"status" => ("status", Kind::Text),
"harness_name" => ("harness_name", Kind::Text),
"harness_session" => ("harness_session", Kind::Text),
"orchestrator_name" => ("orchestrator_name", Kind::Text),
"orchestrator_session" => ("orchestrator_session", Kind::Text),
_ => bail!("unknown variable `{name}`; see docs/filter-variables.md"),
};
Ok(Expr {
sql: format!("tasks.{column}"),
kind,
})
}
fn binary(left: Expr, operator: &BinOp, right: Expr) -> Result<Expr> {
use BinOp::*;
let sql = match operator {
And(_) | Or(_) => {
let kind = compatible(left.kind, right.kind)?;
let is_and = matches!(operator, And(_));
let sql = if is_and {
format!(
"CASE WHEN ({}) THEN ({}) ELSE ({}) END",
truthy(&left),
right.sql,
left.sql
)
} else {
format!(
"CASE WHEN ({}) THEN ({}) ELSE ({}) END",
truthy(&left),
left.sql,
right.sql
)
};
return Ok(Expr { sql, kind });
}
TwoEqual(_) | TildeEqual(_) => {
if left.kind != right.kind && left.kind != Kind::Nil && right.kind != Kind::Nil {
let both_nil = format!("(({}) IS NULL AND ({}) IS NULL)", left.sql, right.sql);
if matches!(operator, TwoEqual(_)) {
both_nil
} else {
format!("NOT {both_nil}")
}
} else {
format!(
"({}) {} ({})",
left.sql,
if matches!(operator, TwoEqual(_)) {
"IS"
} else {
"IS NOT"
},
right.sql
)
}
}
LessThan(_) | LessThanEqual(_) | GreaterThan(_) | GreaterThanEqual(_) => {
let kind = compatible(left.kind, right.kind)?;
ensure!(
matches!(kind, Kind::Number | Kind::Text | Kind::Nil),
"ordering requires numbers or strings"
);
let op = match operator {
LessThan(_) => "<",
LessThanEqual(_) => "<=",
GreaterThan(_) => ">",
_ => ">=",
};
format!("COALESCE((({}) {op} ({})),0)", left.sql, right.sql)
}
Plus(_) | Minus(_) | Star(_) | Slash(_) => {
require(&left, Kind::Number)?;
require(&right, Kind::Number)?;
let op = match operator {
Plus(_) => "+",
Minus(_) => "-",
Star(_) => "*",
_ => "/",
};
let lhs = if matches!(operator, Slash(_)) {
format!("CAST(({}) AS REAL)", left.sql)
} else {
format!("({})", left.sql)
};
return Ok(Expr {
sql: format!("({lhs} {op} ({}))", right.sql),
kind: Kind::Number,
});
}
TwoDots(_) => {
require(&left, Kind::Text)?;
require(&right, Kind::Text)?;
return Ok(Expr {
sql: format!("(({}) || ({}))", left.sql, right.sql),
kind: Kind::Text,
});
}
_ => bail!("unsupported binary operator; see docs/filter.md"),
};
Ok(Expr {
sql,
kind: Kind::Boolean,
})
}