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use crate::base::{
database::{ColumnCoercionError, OwnedTable, OwnedTableError, TableCoercionError},
proof::ProofError,
scalar::Scalar,
};
use snafu::Snafu;
/// Verifiable query errors
#[derive(Snafu, Debug)]
pub enum QueryError {
/// The query result overflowed. This does not mean that the verification failed.
/// This just means that the database was supposed to respond with a result that was too large.
#[snafu(display("Overflow error"))]
Overflow,
/// The query result string could not be decoded. This does not mean that the verification failed.
/// This just means that the database was supposed to respond with a string that was not valid UTF-8.
#[snafu(display("String decode error"))]
InvalidString,
/// Decoding errors other than overflow and invalid string.
#[snafu(display("Miscellaneous decoding error"))]
MiscellaneousDecodingError,
/// Miscellaneous evaluation error.
#[snafu(display("Miscellaneous evaluation error"))]
MiscellaneousEvaluationError,
/// The proof failed to verify.
#[snafu(transparent)]
ProofError {
/// The underlying source error
source: ProofError,
},
/// The table data was invalid. This should never happen because this should get caught by the verifier before reaching this point.
#[snafu(transparent)]
InvalidTable {
/// The underlying source error
source: OwnedTableError,
},
/// The number of columns in the table was invalid.
#[snafu(display("Invalid number of columns"))]
InvalidColumnCount,
}
impl From<TableCoercionError> for QueryError {
fn from(error: TableCoercionError) -> Self {
match error {
TableCoercionError::ColumnCoercionError {
source: ColumnCoercionError::Overflow,
} => QueryError::Overflow,
TableCoercionError::ColumnCoercionError {
source: ColumnCoercionError::InvalidTypeCoercion,
} => ProofError::InvalidTypeCoercion.into(),
TableCoercionError::NameMismatch => ProofError::FieldNamesMismatch.into(),
TableCoercionError::ColumnCountMismatch => ProofError::FieldCountMismatch.into(),
}
}
}
/// The verified results of a query along with metadata produced by verification
pub struct QueryData<S: Scalar> {
/// We use Apache Arrow's [`RecordBatch`] to represent a table
/// result so as to allow for easy interoperability with
/// Apache Arrow Flight.
///
/// See `<https://voltrondata.com/blog/apache-arrow-flight-primer/>`
pub table: OwnedTable<S>,
/// Additionally, there is a 32-byte verification hash that is included with this table.
/// This hash provides evidence that the verification has been run.
pub verification_hash: [u8; 32],
}
/// The result of a query -- either an error or a table.
pub type QueryResult<S> = Result<QueryData<S>, QueryError>;