Adding upstream version 1.64.0+dfsg1.upstream/1.64.0+dfsg1

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 138 insertions, 0 deletions

diff --git a/library/core/src/str/error.rs b/library/core/src/str/error.rs
new file mode 100644
index 000000000..4e569fcc8
--- /dev/null
+++ b/library/core/src/str/error.rs
@@ -0,0 +1,138 @@
+//! Defines utf8 error type.
+
+use crate::fmt;
+
+/// Errors which can occur when attempting to interpret a sequence of [`u8`]
+/// as a string.
+///
+/// As such, the `from_utf8` family of functions and methods for both [`String`]s
+/// and [`&str`]s make use of this error, for example.
+///
+/// [`String`]: ../../std/string/struct.String.html#method.from_utf8
+/// [`&str`]: super::from_utf8
+///
+/// # Examples
+///
+/// This error type’s methods can be used to create functionality
+/// similar to `String::from_utf8_lossy` without allocating heap memory:
+///
+/// ```
+/// fn from_utf8_lossy<F>(mut input: &[u8], mut push: F) where F: FnMut(&str) {
+///     loop {
+///         match std::str::from_utf8(input) {
+///             Ok(valid) => {
+///                 push(valid);
+///                 break
+///             }
+///             Err(error) => {
+///                 let (valid, after_valid) = input.split_at(error.valid_up_to());
+///                 unsafe {
+///                     push(std::str::from_utf8_unchecked(valid))
+///                 }
+///                 push("\u{FFFD}");
+///
+///                 if let Some(invalid_sequence_length) = error.error_len() {
+///                     input = &after_valid[invalid_sequence_length..]
+///                 } else {
+///                     break
+///                 }
+///             }
+///         }
+///     }
+/// }
+/// ```
+#[derive(Copy, Eq, PartialEq, Clone, Debug)]
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Utf8Error {
+    pub(super) valid_up_to: usize,
+    pub(super) error_len: Option<u8>,
+}
+
+impl Utf8Error {
+    /// Returns the index in the given string up to which valid UTF-8 was
+    /// verified.
+    ///
+    /// It is the maximum index such that `from_utf8(&input[..index])`
+    /// would return `Ok(_)`.
+    ///
+    /// # Examples
+    ///
+    /// Basic usage:
+    ///
+    /// ```
+    /// use std::str;
+    ///
+    /// // some invalid bytes, in a vector
+    /// let sparkle_heart = vec![0, 159, 146, 150];
+    ///
+    /// // std::str::from_utf8 returns a Utf8Error
+    /// let error = str::from_utf8(&sparkle_heart).unwrap_err();
+    ///
+    /// // the second byte is invalid here
+    /// assert_eq!(1, error.valid_up_to());
+    /// ```
+    #[stable(feature = "utf8_error", since = "1.5.0")]
+    #[rustc_const_stable(feature = "const_str_from_utf8_shared", since = "1.63.0")]
+    #[must_use]
+    #[inline]
+    pub const fn valid_up_to(&self) -> usize {
+        self.valid_up_to
+    }
+
+    /// Provides more information about the failure:
+    ///
+    /// * `None`: the end of the input was reached unexpectedly.
+    ///   `self.valid_up_to()` is 1 to 3 bytes from the end of the input.
+    ///   If a byte stream (such as a file or a network socket) is being decoded incrementally,
+    ///   this could be a valid `char` whose UTF-8 byte sequence is spanning multiple chunks.
+    ///
+    /// * `Some(len)`: an unexpected byte was encountered.
+    ///   The length provided is that of the invalid byte sequence
+    ///   that starts at the index given by `valid_up_to()`.
+    ///   Decoding should resume after that sequence
+    ///   (after inserting a [`U+FFFD REPLACEMENT CHARACTER`][U+FFFD]) in case of
+    ///   lossy decoding.
+    ///
+    /// [U+FFFD]: ../../std/char/constant.REPLACEMENT_CHARACTER.html
+    #[stable(feature = "utf8_error_error_len", since = "1.20.0")]
+    #[rustc_const_stable(feature = "const_str_from_utf8_shared", since = "1.63.0")]
+    #[must_use]
+    #[inline]
+    pub const fn error_len(&self) -> Option<usize> {
+        // FIXME: This should become `map` again, once it's `const`
+        match self.error_len {
+            Some(len) => Some(len as usize),
+            None => None,
+        }
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl fmt::Display for Utf8Error {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        if let Some(error_len) = self.error_len {
+            write!(
+                f,
+                "invalid utf-8 sequence of {} bytes from index {}",
+                error_len, self.valid_up_to
+            )
+        } else {
+            write!(f, "incomplete utf-8 byte sequence from index {}", self.valid_up_to)
+        }
+    }
+}
+
+/// An error returned when parsing a `bool` using [`from_str`] fails
+///
+/// [`from_str`]: super::FromStr::from_str
+#[derive(Debug, Clone, PartialEq, Eq)]
+#[non_exhaustive]
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct ParseBoolError;
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl fmt::Display for ParseBoolError {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        "provided string was not `true` or `false`".fmt(f)
+    }
+}