| use std::fmt; |
| use std::io; |
| use std::str::Utf8Error; |
| use std::string::FromUtf8Error; |
| |
| /// Custom result type for `cargo_metadata::Error` |
| pub type Result<T> = ::std::result::Result<T, Error>; |
| |
| /// Error returned when executing/parsing `cargo metadata` fails. |
| /// |
| /// # Note about Backtraces |
| /// |
| /// This error type does not contain backtraces, but each error variant |
| /// comes from _one_ specific place, so it's not really needed for the |
| /// inside of this crate. If you need a backtrace down to, but not inside |
| /// of, a failed call of `cargo_metadata` you can do one of multiple thinks: |
| /// |
| /// 1. Convert it to a `failure::Error` (possible using the `?` operator), |
| /// which is similar to a `Box<::std::error::Error + 'static + Send + Sync>`. |
| /// 2. Have appropriate variants in your own error type. E.g. you could wrap |
| /// a `failure::Context<Error>` or add a `failure::Backtrace` field (which |
| /// is empty if `RUST_BACKTRACE` is not set, so it's simple to use). |
| /// 3. You still can place a failure based error into a `error_chain` if you |
| /// really want to. (Either through foreign_links or by making it a field |
| /// value of a `ErrorKind` variant). |
| /// |
| #[derive(Debug)] |
| pub enum Error { |
| /// Error during execution of `cargo metadata` |
| CargoMetadata { |
| /// stderr returned by the `cargo metadata` command |
| stderr: String, |
| }, |
| |
| /// IO Error during execution of `cargo metadata` |
| Io(io::Error), |
| |
| /// Output of `cargo metadata` was not valid utf8 |
| Utf8(Utf8Error), |
| |
| /// Error output of `cargo metadata` was not valid utf8 |
| ErrUtf8(FromUtf8Error), |
| |
| /// Deserialization error (structure of json did not match expected structure) |
| Json(::serde_json::Error), |
| |
| /// The output did not contain any json |
| NoJson, |
| } |
| |
| impl From<io::Error> for Error { |
| fn from(v: io::Error) -> Self { |
| Error::Io(v) |
| } |
| } |
| |
| impl From<Utf8Error> for Error { |
| fn from(v: Utf8Error) -> Self { |
| Error::Utf8(v) |
| } |
| } |
| |
| impl From<FromUtf8Error> for Error { |
| fn from(v: FromUtf8Error) -> Self { |
| Error::ErrUtf8(v) |
| } |
| } |
| |
| impl From<::serde_json::Error> for Error { |
| fn from(v: ::serde_json::Error) -> Self { |
| Error::Json(v) |
| } |
| } |
| |
| impl fmt::Display for Error { |
| fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { |
| match self { |
| Error::CargoMetadata { stderr } => { |
| write!(f, "Error during execution of `cargo metadata`: {}", stderr) |
| } |
| Error::Io(err) => write!(f, "{}", err), |
| Error::Utf8(err) => write!(f, "Cannot convert the stdout of `cargo metadata`: {}", err), |
| Error::ErrUtf8(err) => { |
| write!(f, "Cannot convert the stderr of `cargo metadata`: {}", err) |
| } |
| Error::Json(err) => write!(f, "Failed to interpret `cargo metadata`'s json: {}", err), |
| Error::NoJson => write!( |
| f, |
| "Could not find any json in the output of `cargo metadata`" |
| ), |
| } |
| } |
| } |
| |
| impl ::std::error::Error for Error { |
| fn source(&self) -> Option<&(::std::error::Error + 'static)> { |
| match self { |
| Error::CargoMetadata { .. } => None, |
| Error::Io(err) => Some(err), |
| Error::Utf8(err) => Some(err), |
| Error::ErrUtf8(err) => Some(err), |
| Error::Json(err) => Some(err), |
| Error::NoJson => None, |
| } |
| } |
| } |