509 lines
16 KiB
Rust
509 lines
16 KiB
Rust
// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
|
|
// file at the top-level directory of this distribution and at
|
|
// http://rust-lang.org/COPYRIGHT.
|
|
//
|
|
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
|
|
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
|
|
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
|
|
// option. This file may not be copied, modified, or distributed
|
|
// except according to those terms.
|
|
|
|
/// Entry point of thread panic, for details, see std::macros
|
|
#[macro_export]
|
|
#[allow_internal_unstable]
|
|
#[stable(feature = "core", since = "1.6.0")]
|
|
macro_rules! panic {
|
|
() => (
|
|
panic!("explicit panic")
|
|
);
|
|
($msg:expr) => ({
|
|
static _MSG_FILE_LINE: (&'static str, &'static str, u32) = ($msg, file!(), line!());
|
|
$crate::panicking::panic(&_MSG_FILE_LINE)
|
|
});
|
|
($fmt:expr, $($arg:tt)*) => ({
|
|
// The leading _'s are to avoid dead code warnings if this is
|
|
// used inside a dead function. Just `#[allow(dead_code)]` is
|
|
// insufficient, since the user may have
|
|
// `#[forbid(dead_code)]` and which cannot be overridden.
|
|
static _FILE_LINE: (&'static str, u32) = (file!(), line!());
|
|
$crate::panicking::panic_fmt(format_args!($fmt, $($arg)*), &_FILE_LINE)
|
|
});
|
|
}
|
|
|
|
/// Ensure that a boolean expression is `true` at runtime.
|
|
///
|
|
/// This will invoke the `panic!` macro if the provided expression cannot be
|
|
/// evaluated to `true` at runtime.
|
|
///
|
|
/// Assertions are always checked in both debug and release builds, and cannot
|
|
/// be disabled. See `debug_assert!` for assertions that are not enabled in
|
|
/// release builds by default.
|
|
///
|
|
/// Unsafe code relies on `assert!` to enforce run-time invariants that, if
|
|
/// violated could lead to unsafety.
|
|
///
|
|
/// Other use-cases of `assert!` include
|
|
/// [testing](https://doc.rust-lang.org/book/testing.html) and enforcing
|
|
/// run-time invariants in safe code (whose violation cannot result in unsafety).
|
|
///
|
|
/// This macro has a second version, where a custom panic message can be provided.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// // the panic message for these assertions is the stringified value of the
|
|
/// // expression given.
|
|
/// assert!(true);
|
|
///
|
|
/// fn some_computation() -> bool { true } // a very simple function
|
|
///
|
|
/// assert!(some_computation());
|
|
///
|
|
/// // assert with a custom message
|
|
/// let x = true;
|
|
/// assert!(x, "x wasn't true!");
|
|
///
|
|
/// let a = 3; let b = 27;
|
|
/// assert!(a + b == 30, "a = {}, b = {}", a, b);
|
|
/// ```
|
|
#[macro_export]
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
macro_rules! assert {
|
|
($cond:expr) => (
|
|
if !$cond {
|
|
panic!(concat!("assertion failed: ", stringify!($cond)))
|
|
}
|
|
);
|
|
($cond:expr, $($arg:tt)+) => (
|
|
if !$cond {
|
|
panic!($($arg)+)
|
|
}
|
|
);
|
|
}
|
|
|
|
/// Asserts that two expressions are equal to each other.
|
|
///
|
|
/// On panic, this macro will print the values of the expressions with their
|
|
/// debug representations.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// let a = 3;
|
|
/// let b = 1 + 2;
|
|
/// assert_eq!(a, b);
|
|
/// ```
|
|
#[macro_export]
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
macro_rules! assert_eq {
|
|
($left:expr , $right:expr) => ({
|
|
match (&$left, &$right) {
|
|
(left_val, right_val) => {
|
|
if !(*left_val == *right_val) {
|
|
panic!("assertion failed: `(left == right)` \
|
|
(left: `{:?}`, right: `{:?}`)", left_val, right_val)
|
|
}
|
|
}
|
|
}
|
|
});
|
|
($left:expr , $right:expr, $($arg:tt)*) => ({
|
|
match (&($left), &($right)) {
|
|
(left_val, right_val) => {
|
|
if !(*left_val == *right_val) {
|
|
panic!("assertion failed: `(left == right)` \
|
|
(left: `{:?}`, right: `{:?}`): {}", left_val, right_val,
|
|
format_args!($($arg)*))
|
|
}
|
|
}
|
|
}
|
|
});
|
|
}
|
|
|
|
/// Asserts that two expressions are not equal to each other.
|
|
///
|
|
/// On panic, this macro will print the values of the expressions with their
|
|
/// debug representations.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// let a = 3;
|
|
/// let b = 2;
|
|
/// assert_ne!(a, b);
|
|
/// ```
|
|
#[macro_export]
|
|
#[stable(feature = "assert_ne", since = "1.12.0")]
|
|
macro_rules! assert_ne {
|
|
($left:expr , $right:expr) => ({
|
|
match (&$left, &$right) {
|
|
(left_val, right_val) => {
|
|
if *left_val == *right_val {
|
|
panic!("assertion failed: `(left != right)` \
|
|
(left: `{:?}`, right: `{:?}`)", left_val, right_val)
|
|
}
|
|
}
|
|
}
|
|
});
|
|
($left:expr , $right:expr, $($arg:tt)*) => ({
|
|
match (&($left), &($right)) {
|
|
(left_val, right_val) => {
|
|
if *left_val == *right_val {
|
|
panic!("assertion failed: `(left != right)` \
|
|
(left: `{:?}`, right: `{:?}`): {}", left_val, right_val,
|
|
format_args!($($arg)*))
|
|
}
|
|
}
|
|
}
|
|
});
|
|
}
|
|
|
|
/// Ensure that a boolean expression is `true` at runtime.
|
|
///
|
|
/// This will invoke the `panic!` macro if the provided expression cannot be
|
|
/// evaluated to `true` at runtime.
|
|
///
|
|
/// Like `assert!`, this macro also has a second version, where a custom panic
|
|
/// message can be provided.
|
|
///
|
|
/// Unlike `assert!`, `debug_assert!` statements are only enabled in non
|
|
/// optimized builds by default. An optimized build will omit all
|
|
/// `debug_assert!` statements unless `-C debug-assertions` is passed to the
|
|
/// compiler. This makes `debug_assert!` useful for checks that are too
|
|
/// expensive to be present in a release build but may be helpful during
|
|
/// development.
|
|
///
|
|
/// An unchecked assertion allows a program in an inconsistent state to keep
|
|
/// running, which might have unexpected consequences but does not introduce
|
|
/// unsafety as long as this only happens in safe code. The performance cost
|
|
/// of assertions, is however, not measurable in general. Replacing `assert!`
|
|
/// with `debug_assert!` is thus only encouraged after thorough profiling, and
|
|
/// more importantly, only in safe code!
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// // the panic message for these assertions is the stringified value of the
|
|
/// // expression given.
|
|
/// debug_assert!(true);
|
|
///
|
|
/// fn some_expensive_computation() -> bool { true } // a very simple function
|
|
/// debug_assert!(some_expensive_computation());
|
|
///
|
|
/// // assert with a custom message
|
|
/// let x = true;
|
|
/// debug_assert!(x, "x wasn't true!");
|
|
///
|
|
/// let a = 3; let b = 27;
|
|
/// debug_assert!(a + b == 30, "a = {}, b = {}", a, b);
|
|
/// ```
|
|
#[macro_export]
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
macro_rules! debug_assert {
|
|
($($arg:tt)*) => (if cfg!(debug_assertions) { assert!($($arg)*); })
|
|
}
|
|
|
|
/// Asserts that two expressions are equal to each other.
|
|
///
|
|
/// On panic, this macro will print the values of the expressions with their
|
|
/// debug representations.
|
|
///
|
|
/// Unlike `assert_eq!`, `debug_assert_eq!` statements are only enabled in non
|
|
/// optimized builds by default. An optimized build will omit all
|
|
/// `debug_assert_eq!` statements unless `-C debug-assertions` is passed to the
|
|
/// compiler. This makes `debug_assert_eq!` useful for checks that are too
|
|
/// expensive to be present in a release build but may be helpful during
|
|
/// development.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// let a = 3;
|
|
/// let b = 1 + 2;
|
|
/// debug_assert_eq!(a, b);
|
|
/// ```
|
|
#[macro_export]
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
macro_rules! debug_assert_eq {
|
|
($($arg:tt)*) => (if cfg!(debug_assertions) { assert_eq!($($arg)*); })
|
|
}
|
|
|
|
/// Asserts that two expressions are not equal to each other.
|
|
///
|
|
/// On panic, this macro will print the values of the expressions with their
|
|
/// debug representations.
|
|
///
|
|
/// Unlike `assert_ne!`, `debug_assert_ne!` statements are only enabled in non
|
|
/// optimized builds by default. An optimized build will omit all
|
|
/// `debug_assert_ne!` statements unless `-C debug-assertions` is passed to the
|
|
/// compiler. This makes `debug_assert_ne!` useful for checks that are too
|
|
/// expensive to be present in a release build but may be helpful during
|
|
/// development.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// let a = 3;
|
|
/// let b = 2;
|
|
/// debug_assert_ne!(a, b);
|
|
/// ```
|
|
#[macro_export]
|
|
#[stable(feature = "assert_ne", since = "1.12.0")]
|
|
macro_rules! debug_assert_ne {
|
|
($($arg:tt)*) => (if cfg!(debug_assertions) { assert_ne!($($arg)*); })
|
|
}
|
|
|
|
/// Helper macro for reducing boilerplate code for matching `Result` together
|
|
/// with converting downstream errors.
|
|
///
|
|
/// `try!` matches the given `Result`. In case of the `Ok` variant, the
|
|
/// expression has the value of the wrapped value.
|
|
///
|
|
/// In case of the `Err` variant, it retrieves the inner error. `try!` then
|
|
/// performs conversion using `From`. This provides automatic conversion
|
|
/// between specialized errors and more general ones. The resulting
|
|
/// error is then immediately returned.
|
|
///
|
|
/// Because of the early return, `try!` can only be used in functions that
|
|
/// return `Result`.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// use std::io;
|
|
/// use std::fs::File;
|
|
/// use std::io::prelude::*;
|
|
///
|
|
/// enum MyError {
|
|
/// FileWriteError
|
|
/// }
|
|
///
|
|
/// impl From<io::Error> for MyError {
|
|
/// fn from(e: io::Error) -> MyError {
|
|
/// MyError::FileWriteError
|
|
/// }
|
|
/// }
|
|
///
|
|
/// fn write_to_file_using_try() -> Result<(), MyError> {
|
|
/// let mut file = try!(File::create("my_best_friends.txt"));
|
|
/// try!(file.write_all(b"This is a list of my best friends."));
|
|
/// println!("I wrote to the file");
|
|
/// Ok(())
|
|
/// }
|
|
/// // This is equivalent to:
|
|
/// fn write_to_file_using_match() -> Result<(), MyError> {
|
|
/// let mut file = try!(File::create("my_best_friends.txt"));
|
|
/// match file.write_all(b"This is a list of my best friends.") {
|
|
/// Ok(v) => v,
|
|
/// Err(e) => return Err(From::from(e)),
|
|
/// }
|
|
/// println!("I wrote to the file");
|
|
/// Ok(())
|
|
/// }
|
|
/// ```
|
|
#[macro_export]
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
macro_rules! try {
|
|
($expr:expr) => (match $expr {
|
|
$crate::result::Result::Ok(val) => val,
|
|
$crate::result::Result::Err(err) => {
|
|
return $crate::result::Result::Err($crate::convert::From::from(err))
|
|
}
|
|
})
|
|
}
|
|
|
|
/// Write formatted data into a buffer
|
|
///
|
|
/// This macro accepts any value with `write_fmt` method as a writer, a format string, and a list
|
|
/// of arguments to format.
|
|
///
|
|
/// `write_fmt` method usually comes from an implementation of [`std::fmt::Write`][fmt_write] or
|
|
/// [`std::io::Write`][io_write] traits. These are sometimes called 'writers'.
|
|
///
|
|
/// Passed arguments will be formatted according to the specified format string and the resulting
|
|
/// string will be passed to the writer.
|
|
///
|
|
/// See [`std::fmt`][fmt] for more information on format syntax.
|
|
///
|
|
/// Return value is completely dependent on the 'write_fmt' method.
|
|
///
|
|
/// Common return values are: [`Result`][enum_result], [`io::Result`][type_result]
|
|
///
|
|
/// [fmt]: ../std/fmt/index.html
|
|
/// [fmt_write]: ../std/fmt/trait.Write.html
|
|
/// [io_write]: ../std/io/trait.Write.html
|
|
/// [enum_result]: ../std/result/enum.Result.html
|
|
/// [type_result]: ../std/io/type.Result.html
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// use std::io::Write;
|
|
///
|
|
/// let mut w = Vec::new();
|
|
/// write!(&mut w, "test").unwrap();
|
|
/// write!(&mut w, "formatted {}", "arguments").unwrap();
|
|
///
|
|
/// assert_eq!(w, b"testformatted arguments");
|
|
/// ```
|
|
#[macro_export]
|
|
#[stable(feature = "core", since = "1.6.0")]
|
|
macro_rules! write {
|
|
($dst:expr, $($arg:tt)*) => ($dst.write_fmt(format_args!($($arg)*)))
|
|
}
|
|
|
|
/// Write formatted data into a buffer, with appending a newline.
|
|
///
|
|
/// On all platforms, the newline is the LINE FEED character (`\n`/`U+000A`) alone
|
|
/// (no additional CARRIAGE RETURN (`\r`/`U+000D`).
|
|
///
|
|
/// This macro accepts any value with `write_fmt` method as a writer, a format string, and a list
|
|
/// of arguments to format.
|
|
///
|
|
/// `write_fmt` method usually comes from an implementation of [`std::fmt::Write`][fmt_write] or
|
|
/// [`std::io::Write`][io_write] traits. These are sometimes called 'writers'.
|
|
///
|
|
/// Passed arguments will be formatted according to the specified format string and the resulting
|
|
/// string will be passed to the writer.
|
|
///
|
|
/// See [`std::fmt`][fmt] for more information on format syntax.
|
|
///
|
|
/// Return value is completely dependent on the 'write_fmt' method.
|
|
///
|
|
/// Common return values are: [`Result`][enum_result], [`io::Result`][type_result]
|
|
///
|
|
/// [fmt]: ../std/fmt/index.html
|
|
/// [fmt_write]: ../std/fmt/trait.Write.html
|
|
/// [io_write]: ../std/io/trait.Write.html
|
|
/// [enum_result]: ../std/result/enum.Result.html
|
|
/// [type_result]: ../std/io/type.Result.html
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// use std::io::Write;
|
|
///
|
|
/// let mut w = Vec::new();
|
|
/// writeln!(&mut w, "test").unwrap();
|
|
/// writeln!(&mut w, "formatted {}", "arguments").unwrap();
|
|
///
|
|
/// assert_eq!(&w[..], "test\nformatted arguments\n".as_bytes());
|
|
/// ```
|
|
#[macro_export]
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
macro_rules! writeln {
|
|
($dst:expr, $fmt:expr) => (
|
|
write!($dst, concat!($fmt, "\n"))
|
|
);
|
|
($dst:expr, $fmt:expr, $($arg:tt)*) => (
|
|
write!($dst, concat!($fmt, "\n"), $($arg)*)
|
|
);
|
|
}
|
|
|
|
/// A utility macro for indicating unreachable code.
|
|
///
|
|
/// This is useful any time that the compiler can't determine that some code is unreachable. For
|
|
/// example:
|
|
///
|
|
/// * Match arms with guard conditions.
|
|
/// * Loops that dynamically terminate.
|
|
/// * Iterators that dynamically terminate.
|
|
///
|
|
/// # Panics
|
|
///
|
|
/// This will always panic.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// Match arms:
|
|
///
|
|
/// ```
|
|
/// # #[allow(dead_code)]
|
|
/// fn foo(x: Option<i32>) {
|
|
/// match x {
|
|
/// Some(n) if n >= 0 => println!("Some(Non-negative)"),
|
|
/// Some(n) if n < 0 => println!("Some(Negative)"),
|
|
/// Some(_) => unreachable!(), // compile error if commented out
|
|
/// None => println!("None")
|
|
/// }
|
|
/// }
|
|
/// ```
|
|
///
|
|
/// Iterators:
|
|
///
|
|
/// ```
|
|
/// # #[allow(dead_code)]
|
|
/// fn divide_by_three(x: u32) -> u32 { // one of the poorest implementations of x/3
|
|
/// for i in 0.. {
|
|
/// if 3*i < i { panic!("u32 overflow"); }
|
|
/// if x < 3*i { return i-1; }
|
|
/// }
|
|
/// unreachable!();
|
|
/// }
|
|
/// ```
|
|
#[macro_export]
|
|
#[stable(feature = "core", since = "1.6.0")]
|
|
macro_rules! unreachable {
|
|
() => ({
|
|
panic!("internal error: entered unreachable code")
|
|
});
|
|
($msg:expr) => ({
|
|
unreachable!("{}", $msg)
|
|
});
|
|
($fmt:expr, $($arg:tt)*) => ({
|
|
panic!(concat!("internal error: entered unreachable code: ", $fmt), $($arg)*)
|
|
});
|
|
}
|
|
|
|
/// A standardized placeholder for marking unfinished code. It panics with the
|
|
/// message `"not yet implemented"` when executed.
|
|
///
|
|
/// This can be useful if you are prototyping and are just looking to have your
|
|
/// code typecheck, or if you're implementing a trait that requires multiple
|
|
/// methods, and you're only planning on using one of them.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// Here's an example of some in-progress code. We have a trait `Foo`:
|
|
///
|
|
/// ```
|
|
/// trait Foo {
|
|
/// fn bar(&self);
|
|
/// fn baz(&self);
|
|
/// }
|
|
/// ```
|
|
///
|
|
/// We want to implement `Foo` on one of our types, but we also want to work on
|
|
/// just `bar()` first. In order for our code to compile, we need to implement
|
|
/// `baz()`, so we can use `unimplemented!`:
|
|
///
|
|
/// ```
|
|
/// # trait Foo {
|
|
/// # fn bar(&self);
|
|
/// # fn baz(&self);
|
|
/// # }
|
|
/// struct MyStruct;
|
|
///
|
|
/// impl Foo for MyStruct {
|
|
/// fn bar(&self) {
|
|
/// // implementation goes here
|
|
/// }
|
|
///
|
|
/// fn baz(&self) {
|
|
/// // let's not worry about implementing baz() for now
|
|
/// unimplemented!();
|
|
/// }
|
|
/// }
|
|
///
|
|
/// fn main() {
|
|
/// let s = MyStruct;
|
|
/// s.bar();
|
|
///
|
|
/// // we aren't even using baz() yet, so this is fine.
|
|
/// }
|
|
/// ```
|
|
#[macro_export]
|
|
#[stable(feature = "core", since = "1.6.0")]
|
|
macro_rules! unimplemented {
|
|
() => (panic!("not yet implemented"))
|
|
}
|