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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-19 00:47:55 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-19 00:47:55 +0000
commit26a029d407be480d791972afb5975cf62c9360a6 (patch)
treef435a8308119effd964b339f76abb83a57c29483 /third_party/rust/bitflags/src/parser.rs
parentInitial commit. (diff)
downloadfirefox-26a029d407be480d791972afb5975cf62c9360a6.tar.xz
firefox-26a029d407be480d791972afb5975cf62c9360a6.zip
Adding upstream version 124.0.1.upstream/124.0.1
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'third_party/rust/bitflags/src/parser.rs')
-rw-r--r--third_party/rust/bitflags/src/parser.rs247
1 files changed, 247 insertions, 0 deletions
diff --git a/third_party/rust/bitflags/src/parser.rs b/third_party/rust/bitflags/src/parser.rs
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+/*!
+Parsing flags from text.
+
+Format and parse a flags value as text using the following grammar:
+
+- _Flags:_ (_Whitespace_ _Flag_ _Whitespace_)`|`*
+- _Flag:_ _Name_ | _Hex Number_
+- _Name:_ The name of any defined flag
+- _Hex Number_: `0x`([0-9a-fA-F])*
+- _Whitespace_: (\s)*
+
+As an example, this is how `Flags::A | Flags::B | 0x0c` can be represented as text:
+
+```text
+A | B | 0x0c
+```
+
+Alternatively, it could be represented without whitespace:
+
+```text
+A|B|0x0C
+```
+
+Note that identifiers are *case-sensitive*, so the following is *not equivalent*:
+
+```text
+a|b|0x0C
+```
+*/
+
+#![allow(clippy::let_unit_value)]
+
+use core::fmt::{self, Write};
+
+use crate::{Bits, Flags};
+
+/**
+Write a flags value as text.
+
+Any bits that aren't part of a contained flag will be formatted as a hex number.
+*/
+pub fn to_writer<B: Flags>(flags: &B, mut writer: impl Write) -> Result<(), fmt::Error>
+where
+ B::Bits: WriteHex,
+{
+ // A formatter for bitflags that produces text output like:
+ //
+ // A | B | 0xf6
+ //
+ // The names of set flags are written in a bar-separated-format,
+ // followed by a hex number of any remaining bits that are set
+ // but don't correspond to any flags.
+
+ // Iterate over known flag values
+ let mut first = true;
+ let mut iter = flags.iter_names();
+ for (name, _) in &mut iter {
+ if !first {
+ writer.write_str(" | ")?;
+ }
+
+ first = false;
+ writer.write_str(name)?;
+ }
+
+ // Append any extra bits that correspond to flags to the end of the format
+ let remaining = iter.remaining().bits();
+ if remaining != B::Bits::EMPTY {
+ if !first {
+ writer.write_str(" | ")?;
+ }
+
+ writer.write_str("0x")?;
+ remaining.write_hex(writer)?;
+ }
+
+ fmt::Result::Ok(())
+}
+
+pub(crate) struct AsDisplay<'a, B>(pub(crate) &'a B);
+
+impl<'a, B: Flags> fmt::Display for AsDisplay<'a, B>
+where
+ B::Bits: WriteHex,
+{
+ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+ to_writer(self.0, f)
+ }
+}
+
+/**
+Parse a flags value from text.
+
+This function will fail on any names that don't correspond to defined flags.
+Unknown bits will be retained.
+*/
+pub fn from_str<B: Flags>(input: &str) -> Result<B, ParseError>
+where
+ B::Bits: ParseHex,
+{
+ let mut parsed_flags = B::empty();
+
+ // If the input is empty then return an empty set of flags
+ if input.trim().is_empty() {
+ return Ok(parsed_flags);
+ }
+
+ for flag in input.split('|') {
+ let flag = flag.trim();
+
+ // If the flag is empty then we've got missing input
+ if flag.is_empty() {
+ return Err(ParseError::empty_flag());
+ }
+
+ // If the flag starts with `0x` then it's a hex number
+ // Parse it directly to the underlying bits type
+ let parsed_flag = if let Some(flag) = flag.strip_prefix("0x") {
+ let bits =
+ <B::Bits>::parse_hex(flag).map_err(|_| ParseError::invalid_hex_flag(flag))?;
+
+ B::from_bits_retain(bits)
+ }
+ // Otherwise the flag is a name
+ // The generated flags type will determine whether
+ // or not it's a valid identifier
+ else {
+ B::from_name(flag).ok_or_else(|| ParseError::invalid_named_flag(flag))?
+ };
+
+ parsed_flags.insert(parsed_flag);
+ }
+
+ Ok(parsed_flags)
+}
+
+/**
+Encode a value as a hex string.
+
+Implementors of this trait should not write the `0x` prefix.
+*/
+pub trait WriteHex {
+ /// Write the value as hex.
+ fn write_hex<W: fmt::Write>(&self, writer: W) -> fmt::Result;
+}
+
+/**
+Parse a value from a hex string.
+*/
+pub trait ParseHex {
+ /// Parse the value from hex.
+ fn parse_hex(input: &str) -> Result<Self, ParseError>
+ where
+ Self: Sized;
+}
+
+/// An error encountered while parsing flags from text.
+#[derive(Debug)]
+pub struct ParseError(ParseErrorKind);
+
+#[derive(Debug)]
+#[allow(clippy::enum_variant_names)]
+enum ParseErrorKind {
+ EmptyFlag,
+ InvalidNamedFlag {
+ #[cfg(not(feature = "std"))]
+ got: (),
+ #[cfg(feature = "std")]
+ got: String,
+ },
+ InvalidHexFlag {
+ #[cfg(not(feature = "std"))]
+ got: (),
+ #[cfg(feature = "std")]
+ got: String,
+ },
+}
+
+impl ParseError {
+ /// An invalid hex flag was encountered.
+ pub fn invalid_hex_flag(flag: impl fmt::Display) -> Self {
+ let _flag = flag;
+
+ let got = {
+ #[cfg(feature = "std")]
+ {
+ _flag.to_string()
+ }
+ };
+
+ ParseError(ParseErrorKind::InvalidHexFlag { got })
+ }
+
+ /// A named flag that doesn't correspond to any on the flags type was encountered.
+ pub fn invalid_named_flag(flag: impl fmt::Display) -> Self {
+ let _flag = flag;
+
+ let got = {
+ #[cfg(feature = "std")]
+ {
+ _flag.to_string()
+ }
+ };
+
+ ParseError(ParseErrorKind::InvalidNamedFlag { got })
+ }
+
+ /// A hex or named flag wasn't found between separators.
+ pub const fn empty_flag() -> Self {
+ ParseError(ParseErrorKind::EmptyFlag)
+ }
+}
+
+impl fmt::Display for ParseError {
+ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+ match &self.0 {
+ ParseErrorKind::InvalidNamedFlag { got } => {
+ let _got = got;
+
+ write!(f, "unrecognized named flag")?;
+
+ #[cfg(feature = "std")]
+ {
+ write!(f, " `{}`", _got)?;
+ }
+ }
+ ParseErrorKind::InvalidHexFlag { got } => {
+ let _got = got;
+
+ write!(f, "invalid hex flag")?;
+
+ #[cfg(feature = "std")]
+ {
+ write!(f, " `{}`", _got)?;
+ }
+ }
+ ParseErrorKind::EmptyFlag => {
+ write!(f, "encountered empty flag")?;
+ }
+ }
+
+ Ok(())
+ }
+}
+
+#[cfg(feature = "std")]
+impl std::error::Error for ParseError {}