Struct UnescapeError 

pub struct UnescapeError { /* private fields */ }

An error that can occur during the JSON string unescaping process.

Implementations

impl UnescapeError

pub fn kind(&self) -> UnescapeErrorKind

Returns the specific kind of error that occurred.

This can be used to programmatically handle different error types, such as distinguishing between a malformed hex sequence and an invalid escape character.

Example

let mut unescaper = unescape(r#"\u123Z"#);
let err = unescaper.next().unwrap().unwrap_err();

match err.kind() {
    UnescapeErrorKind::InvalidHex(InvalidHexError { found, .. }) => {
        // We can inspect the exact invalid character found.
        assert_eq!(found, b'Z');
    }
    _ => panic!("Expected an InvalidHex error"),
}

pub fn offset(&self) -> u8

Returns the byte offset from the start of the escape sequence (\) where the error was detected.

• For \x, the offset is 1 (pointing to x).
• For \u123?, the offset is 5 (pointing to ?).
• For a lone surrogate \uD800, the offset is 6 (pointing after the sequence).

This is useful for providing detailed error messages that can point to the exact location of the problem in the source string.

Example

let json_string_content = r#"bad escape \x here"#;
let mut unescaper = unescape(json_string_content);

// read off 'bad escape '
let first = unescaper.next().unwrap().unwrap();
assert_eq!(first, b"bad escape ");

let err = unescaper.next().unwrap().unwrap_err();

// The error occurred at the 'x', which is 1 byte after the '\'
assert_eq!(err.offset(), 1);

// You could use this to highlight the error in the original input
let backslash_pos = json_string_content.find('\\').unwrap();
let error_pos = backslash_pos + err.offset() as usize;
assert_eq!(json_string_content.as_bytes()[error_pos], b'x');

// The generated error message also includes this info.
let expected_msg = "invalid escape: '\\0x78' at offset 1";
assert_eq!(err.to_string(), expected_msg);

Trait Implementations

impl Clone for UnescapeError

fn clone(&self) -> UnescapeError

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for UnescapeError

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Display for UnescapeError

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Error for UnescapeError

fn source(&self) -> Option<&(dyn Error + 'static)>

Returns the lower-level source of this error, if any.

fn description(&self) -> &str

👎Deprecated since 1.42.0: use the Display impl or to_string()

fn cause(&self) -> Option<&dyn Error>

👎Deprecated since 1.33.0: replaced by Error::source, which can support downcasting

fn provide<'a>(&'a self, request: &mut Request<'a>)

🔬This is a nightly-only experimental API. (error_generic_member_access)

Provides type-based access to context intended for error reports.

impl PartialEq for UnescapeError

fn eq(&self, other: &UnescapeError) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Copy for UnescapeError

impl Eq for UnescapeError

impl StructuralPartialEq for UnescapeError