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use crate::panic::BoxedPanic; use crate::{ AccessError, Hash, Integer, Panic, Protocol, StackError, TypeInfo, Unit, Value, ValueType, VmHaltInfo, }; use std::sync::Arc; use thiserror::Error; /// Errors raised by the execution of the virtual machine. #[derive(Error, Debug)] #[error(transparent)] pub struct VmError { kind: Box<VmErrorKind>, } impl VmError { /// Return an error encapsulating a panic. pub fn panic<D>(message: D) -> Self where D: BoxedPanic, { Self::from(VmErrorKind::Panic { reason: Panic::custom(message), }) } /// Bad argument. pub fn bad_argument<T>(arg: usize, value: &Value) -> Result<Self, VmError> where T: ValueType, { Ok(Self::from(VmErrorKind::BadArgumentType { arg, expected: T::type_info(), actual: value.type_info()?, })) } /// Construct an expected error. pub fn expected<T>(actual: TypeInfo) -> Self where T: ValueType, { Self::from(VmErrorKind::Expected { expected: T::type_info(), actual, }) } /// Construct an expected any error. pub fn expected_any(actual: TypeInfo) -> Self { Self::from(VmErrorKind::ExpectedAny { actual }) } /// Access the underlying error kind. pub fn kind(&self) -> &VmErrorKind { &*self.kind } /// Convert into an unwinded vm error. pub fn into_unwinded(self, unit: &Arc<Unit>, ip: usize) -> Self { if let VmErrorKind::Unwound { .. } = &*self.kind { return self; } Self::from(VmErrorKind::Unwound { kind: self.kind, unit: unit.clone(), ip, }) } /// Unpack an unwinded error, if it is present. pub fn into_unwound(self) -> (Self, Option<(Arc<Unit>, usize)>) { match *self.kind { VmErrorKind::Unwound { kind, unit, ip } => { let error = Self { kind }; (error, Some((unit, ip))) } kind => (Self::from(kind), None), } } /// Unsmuggles the vm error, returning Ok(Self) in case the error is /// critical and should be propagated unaltered. pub fn unpack_critical(self) -> Result<Self, Self> { if self.is_critical() { Err(self) } else { Ok(self) } } /// Test if the error is critical and should be propagated unaltered or not. /// /// Returns `true` if the error should be propagated. fn is_critical(&self) -> bool { match &*self.kind { VmErrorKind::Panic { .. } => true, VmErrorKind::Unwound { .. } => true, _ => false, } } } impl<E> From<E> for VmError where VmErrorKind: From<E>, { fn from(err: E) -> Self { Self { kind: Box::new(VmErrorKind::from(err)), } } } /// The kind of error encountered. #[derive(Debug, Error)] pub enum VmErrorKind { /// A vm error that was propagated from somewhere else. /// /// In order to represent this, we need to preserve the instruction pointer /// and eventually unit from where the error happened. #[error("{kind} (at {ip})")] Unwound { /// The wrapper error. kind: Box<VmErrorKind>, /// Associated unit. unit: Arc<Unit>, /// The instruction pointer of where the original error happened. ip: usize, }, /// The virtual machine panicked for a specific reason. #[error("panicked `{reason}`")] Panic { /// The reason for the panic. reason: Panic, }, /// Raised when we try to access an empty execution. #[error("no running virtual machines")] NoRunningVm, /// The virtual machine stopped for an unexpected reason. #[error("halted for unexpected reason `{halt}`")] Halted { /// The reason why the virtual machine stopped. halt: VmHaltInfo, }, /// Error raised when external format function results in error. #[error("failed to format argument")] FormatError, /// Error raised when interacting with the stack. #[error("stack error: {error}")] StackError { /// The source error. #[from] error: StackError, }, /// The virtual machine encountered a numerical overflow. #[error("numerical overflow")] Overflow, /// The virtual machine encountered a numerical underflow. #[error("numerical underflow")] Underflow, /// The virtual machine encountered a divide-by-zero. #[error("division by zero")] DivideByZero, /// Failure to lookup function. #[error("missing function with hash `{hash}`")] MissingFunction { /// Hash of function to look up. hash: Hash, }, /// Failure to lookup instance function. #[error("missing instance function `{hash}` for `{instance}`")] MissingInstanceFunction { /// Hash of function to look up. hash: Hash, /// The instance type we tried to look up function on. instance: TypeInfo, }, /// Instruction pointer went out-of-bounds. #[error("instruction pointer is out-of-bounds")] IpOutOfBounds, /// Tried to await something on the stack which can't be await:ed. #[error("unsupported target for .await `{actual}`")] UnsupportedAwait { /// The actual target. actual: TypeInfo, }, /// Unsupported binary operation. #[error("unsupported vm operation `{lhs} {op} {rhs}`")] UnsupportedBinaryOperation { /// Operation. op: &'static str, /// Left-hand side operator. lhs: TypeInfo, /// Right-hand side operator. rhs: TypeInfo, }, /// Unsupported unary operation. #[error("unsupported vm operation `{op}{operand}`")] UnsupportedUnaryOperation { /// Operation. op: &'static str, /// Operand. operand: TypeInfo, }, /// Protocol not implemented on type. #[error("`{actual}` does not implement the `{protocol}` protocol")] MissingProtocol { /// The missing protocol. protocol: Protocol, /// The encountered argument. actual: TypeInfo, }, /// Indicates that a static string is missing for the given slot. #[error("static string slot `{slot}` does not exist")] MissingStaticString { /// Slot which is missing a static string. slot: usize, }, /// Indicates that a static object keys is missing for the given slot. #[error("static object keys slot `{slot}` does not exist")] MissingStaticObjectKeys { /// Slot which is missing a static object keys. slot: usize, }, /// Wrong number of arguments provided in call. #[error("wrong number of arguments `{actual}`, expected `{expected}`")] BadArgumentCount { /// The actual number of arguments. actual: usize, /// The expected number of arguments. expected: usize, }, /// Failure to convert from one type to another. #[error("bad argument #{arg}, expected `{expected}` but got `{actual}`")] BadArgumentType { /// The argument location that was converted. arg: usize, /// The argument type we expected. expected: TypeInfo, /// The argument type we got. actual: TypeInfo, }, /// Failure to convert from one type to another. #[error("bad argument #{arg} (expected `{to}`): {error}")] BadArgument { /// The underlying stack error. #[source] error: VmError, /// The argument location that was converted. arg: usize, /// The native type we attempt to convert to. to: &'static str, }, /// Failure to convert return value. #[error("bad return value (expected `{ret}`): {error}")] BadReturn { /// Error describing the failed conversion. #[source] error: VmError, /// Type of the return value we attempted to convert. ret: &'static str, }, /// An index set operation that is not supported. #[error("the index set operation `{target}[{index}] = {value}` is not supported")] UnsupportedIndexSet { /// The target type to set. target: TypeInfo, /// The index to set. index: TypeInfo, /// The value to set. value: TypeInfo, }, /// An index get operation that is not supported. #[error("the index get operation `{target}[{index}]` is not supported")] UnsupportedIndexGet { /// The target type to get. target: TypeInfo, /// The index to get. index: TypeInfo, }, /// An tuple index get operation that is not supported. #[error("the tuple index get operation is not supported on `{target}`")] UnsupportedTupleIndexGet { /// The target type we tried to perform the tuple indexing on. target: TypeInfo, }, /// An tuple index set operation that is not supported. #[error("the tuple index set operation is not supported on `{target}`")] UnsupportedTupleIndexSet { /// The target type we tried to perform the tuple indexing on. target: TypeInfo, }, /// An object slot index get operation that is not supported. #[error("field not available on `{target}`")] UnsupportedObjectSlotIndexGet { /// The target type we tried to perform the object indexing on. target: TypeInfo, }, /// An is operation is not supported. #[error("`{value} is {test_type}` is not supported")] UnsupportedIs { /// The argument that is not supported. value: TypeInfo, /// The type that is not supported. test_type: TypeInfo, }, /// Encountered a value that could not be called as a function #[error("`{actual_type}` cannot be called since it's not a function")] UnsupportedCallFn { /// The type that could not be called. actual_type: TypeInfo, }, /// Tried to fetch an index in an object that doesn't exist. #[error("missing index by static string slot `{slot}` in object")] ObjectIndexMissing { /// The static string slot corresponding to the index that is missing. slot: usize, }, /// Tried to access an index that was missing on a type. #[error("missing index `{}` on `{target}`")] MissingIndex { /// Type where field did not exist. target: TypeInfo, /// Index that we tried to access. index: Integer, }, /// Missing a struct field. #[error("missing field `{field}` on `{target}`")] MissingField { /// Type where field did not exist. target: TypeInfo, /// Field that was missing. field: String, }, /// Error raised when we try to unwrap something that is not an option or /// result. #[error("expected result or option with value to unwrap, but got `{actual}`")] UnsupportedUnwrap { /// The actual operand. actual: TypeInfo, }, /// Error raised when we try to unwrap an Option that is not Some. #[error("expected Some value, but got `None`")] UnsupportedUnwrapNone, /// Error raised when we try to unwrap a Result that is not Ok. #[error("expected Ok value, but got `Err({err})`")] UnsupportedUnwrapErr { /// The error variant. err: TypeInfo, }, /// Value is not supported for `is-value` test. #[error("expected result or option as value, but got `{actual}`")] UnsupportedIsValueOperand { /// The actual operand. actual: TypeInfo, }, /// Trying to resume a generator that has completed. #[error("cannot resume a generator that has completed")] GeneratorComplete, /// Trying to access an inaccessible reference. #[error("failed to access value: {error}")] AccessError { /// Source error. #[from] error: AccessError, }, /// Error raised when we expected one type, but got another. #[error("expected `{expected}`, but found `{actual}`")] Expected { /// The expected value type info. expected: TypeInfo, /// The actual type found. actual: TypeInfo, }, /// Error raised when we expected a value. #[error("expected `Any` type, but found `{actual}`")] ExpectedAny { /// The actual type observed instead. actual: TypeInfo, }, /// Failure to convert a number into an integer. #[error("failed to convert value `{from}` to integer `{to}`")] ValueToIntegerCoercionError { /// Number we tried to convert from. from: Integer, /// Number type we tried to convert to. to: &'static str, }, /// Failure to convert an integer into a value. #[error("failed to convert integer `{from}` to value `{to}`")] IntegerToValueCoercionError { /// Number we tried to convert from. from: Integer, /// Number type we tried to convert to. to: &'static str, }, /// Error raised when we expected an tuple of the given length. #[error("expected a tuple of length `{expected}`, but found one with length `{actual}`")] ExpectedTupleLength { /// The actual length observed. actual: usize, /// The expected tuple length. expected: usize, }, /// Internal error that happens when we run out of items in a list. #[error("unexpectedly ran out of items to iterate over")] IterationError, } impl VmErrorKind { /// Unpack an unwound error, if it is present. pub fn into_unwound_ref(&self) -> (&Self, Option<(Arc<Unit>, usize)>) { match self { VmErrorKind::Unwound { kind, unit, ip } => (&*kind, Some((unit.clone(), *ip))), kind => (kind, None), } } }