Struct std::ffi::OsString1.0.0[][src]

pub struct OsString { /* fields omitted */ }
Expand description

A type that can represent owned, mutable platform-native strings, but is cheaply inter-convertible with Rust strings.

The need for this type arises from the fact that:

  • On Unix systems, strings are often arbitrary sequences of non-zero bytes, in many cases interpreted as UTF-8.

  • On Windows, strings are often arbitrary sequences of non-zero 16-bit values, interpreted as UTF-16 when it is valid to do so.

  • In Rust, strings are always valid UTF-8, which may contain zeros.

OsString and OsStr bridge this gap by simultaneously representing Rust and platform-native string values, and in particular allowing a Rust string to be converted into an “OS” string with no cost if possible. A consequence of this is that OsString instances are not NUL terminated; in order to pass to e.g., Unix system call, you should create a CStr.

OsString is to &OsStr as String is to &str: the former in each pair are owned strings; the latter are borrowed references.

Note, OsString and OsStr internally do not necessarily hold strings in the form native to the platform; While on Unix, strings are stored as a sequence of 8-bit values, on Windows, where strings are 16-bit value based as just discussed, strings are also actually stored as a sequence of 8-bit values, encoded in a less-strict variant of UTF-8. This is useful to understand when handling capacity and length values.

Creating an OsString

From a Rust string: OsString implements From<String>, so you can use my_string.from to create an OsString from a normal Rust string.

From slices: Just like you can start with an empty Rust String and then String::push_str &str sub-string slices into it, you can create an empty OsString with the OsString::new method and then push string slices into it with the OsString::push method.

Extracting a borrowed reference to the whole OS string

You can use the OsString::as_os_str method to get an &OsStr from an OsString; this is effectively a borrowed reference to the whole string.

Conversions

See the module’s toplevel documentation about conversions for a discussion on the traits which OsString implements for conversions from/to native representations.

Implementations

Constructs a new empty OsString.

Examples

use std::ffi::OsString;

let os_string = OsString::new();
Run

Converts to an OsStr slice.

Examples

use std::ffi::{OsString, OsStr};

let os_string = OsString::from("foo");
let os_str = OsStr::new("foo");
assert_eq!(os_string.as_os_str(), os_str);
Run

Converts the OsString into a String if it contains valid Unicode data.

On failure, ownership of the original OsString is returned.

Examples

use std::ffi::OsString;

let os_string = OsString::from("foo");
let string = os_string.into_string();
assert_eq!(string, Ok(String::from("foo")));
Run

Extends the string with the given &OsStr slice.

Examples

use std::ffi::OsString;

let mut os_string = OsString::from("foo");
os_string.push("bar");
assert_eq!(&os_string, "foobar");
Run

Creates a new OsString with the given capacity.

The string will be able to hold exactly capacity length units of other OS strings without reallocating. If capacity is 0, the string will not allocate.

See main OsString documentation information about encoding.

Examples

use std::ffi::OsString;

let mut os_string = OsString::with_capacity(10);
let capacity = os_string.capacity();

// This push is done without reallocating
os_string.push("foo");

assert_eq!(capacity, os_string.capacity());
Run

Truncates the OsString to zero length.

Examples

use std::ffi::OsString;

let mut os_string = OsString::from("foo");
assert_eq!(&os_string, "foo");

os_string.clear();
assert_eq!(&os_string, "");
Run

Returns the capacity this OsString can hold without reallocating.

See OsString introduction for information about encoding.

Examples

use std::ffi::OsString;

let os_string = OsString::with_capacity(10);
assert!(os_string.capacity() >= 10);
Run

Reserves capacity for at least additional more capacity to be inserted in the given OsString.

The collection may reserve more space to avoid frequent reallocations.

Examples

use std::ffi::OsString;

let mut s = OsString::new();
s.reserve(10);
assert!(s.capacity() >= 10);
Run

Reserves the minimum capacity for exactly additional more capacity to be inserted in the given OsString. Does nothing if the capacity is already sufficient.

Note that the allocator may give the collection more space than it requests. Therefore, capacity can not be relied upon to be precisely minimal. Prefer reserve if future insertions are expected.

Examples

use std::ffi::OsString;

let mut s = OsString::new();
s.reserve_exact(10);
assert!(s.capacity() >= 10);
Run

Shrinks the capacity of the OsString to match its length.

Examples

use std::ffi::OsString;

let mut s = OsString::from("foo");

s.reserve(100);
assert!(s.capacity() >= 100);

s.shrink_to_fit();
assert_eq!(3, s.capacity());
Run
🔬 This is a nightly-only experimental API. (shrink_to #56431)

new API

Shrinks the capacity of the OsString with a lower bound.

The capacity will remain at least as large as both the length and the supplied value.

If the current capacity is less than the lower limit, this is a no-op.

Examples

#![feature(shrink_to)]
use std::ffi::OsString;

let mut s = OsString::from("foo");

s.reserve(100);
assert!(s.capacity() >= 100);

s.shrink_to(10);
assert!(s.capacity() >= 10);
s.shrink_to(0);
assert!(s.capacity() >= 3);
Run

Converts this OsString into a boxed OsStr.

Examples

use std::ffi::{OsString, OsStr};

let s = OsString::from("hello");

let b: Box<OsStr> = s.into_boxed_os_str();
Run

Methods from Deref<Target = OsStr>

Yields a &str slice if the OsStr is valid Unicode.

This conversion may entail doing a check for UTF-8 validity.

Examples

use std::ffi::OsStr;

let os_str = OsStr::new("foo");
assert_eq!(os_str.to_str(), Some("foo"));
Run

Converts an OsStr to a Cow<str>.

Any non-Unicode sequences are replaced with U+FFFD REPLACEMENT CHARACTER.

Examples

Calling to_string_lossy on an OsStr with invalid unicode:

// Note, due to differences in how Unix and Windows represent strings,
// we are forced to complicate this example, setting up example `OsStr`s
// with different source data and via different platform extensions.
// Understand that in reality you could end up with such example invalid
// sequences simply through collecting user command line arguments, for
// example.

#[cfg(unix)] {
    use std::ffi::OsStr;
    use std::os::unix::ffi::OsStrExt;

    // Here, the values 0x66 and 0x6f correspond to 'f' and 'o'
    // respectively. The value 0x80 is a lone continuation byte, invalid
    // in a UTF-8 sequence.
    let source = [0x66, 0x6f, 0x80, 0x6f];
    let os_str = OsStr::from_bytes(&source[..]);

    assert_eq!(os_str.to_string_lossy(), "fo�o");
}
#[cfg(windows)] {
    use std::ffi::OsString;
    use std::os::windows::prelude::*;

    // Here the values 0x0066 and 0x006f correspond to 'f' and 'o'
    // respectively. The value 0xD800 is a lone surrogate half, invalid
    // in a UTF-16 sequence.
    let source = [0x0066, 0x006f, 0xD800, 0x006f];
    let os_string = OsString::from_wide(&source[..]);
    let os_str = os_string.as_os_str();

    assert_eq!(os_str.to_string_lossy(), "fo�o");
}
Run

Copies the slice into an owned OsString.

Examples

use std::ffi::{OsStr, OsString};

let os_str = OsStr::new("foo");
let os_string = os_str.to_os_string();
assert_eq!(os_string, OsString::from("foo"));
Run

Checks whether the OsStr is empty.

Examples

use std::ffi::OsStr;

let os_str = OsStr::new("");
assert!(os_str.is_empty());

let os_str = OsStr::new("foo");
assert!(!os_str.is_empty());
Run

Returns the length of this OsStr.

Note that this does not return the number of bytes in the string in OS string form.

The length returned is that of the underlying storage used by OsStr. As discussed in the OsString introduction, OsString and OsStr store strings in a form best suited for cheap inter-conversion between native-platform and Rust string forms, which may differ significantly from both of them, including in storage size and encoding.

This number is simply useful for passing to other methods, like OsString::with_capacity to avoid reallocations.

Examples

use std::ffi::OsStr;

let os_str = OsStr::new("");
assert_eq!(os_str.len(), 0);

let os_str = OsStr::new("foo");
assert_eq!(os_str.len(), 3);
Run

Converts this string to its ASCII lower case equivalent in-place.

ASCII letters ‘A’ to ‘Z’ are mapped to ‘a’ to ‘z’, but non-ASCII letters are unchanged.

To return a new lowercased value without modifying the existing one, use OsStr::to_ascii_lowercase.

Examples

use std::ffi::OsString;

let mut s = OsString::from("GRÜßE, JÜRGEN ❤");

s.make_ascii_lowercase();

assert_eq!("grÜße, jÜrgen ❤", s);
Run

Converts this string to its ASCII upper case equivalent in-place.

ASCII letters ‘a’ to ‘z’ are mapped to ‘A’ to ‘Z’, but non-ASCII letters are unchanged.

To return a new uppercased value without modifying the existing one, use OsStr::to_ascii_uppercase.

Examples

use std::ffi::OsString;

let mut s = OsString::from("Grüße, Jürgen ❤");

s.make_ascii_uppercase();

assert_eq!("GRüßE, JüRGEN ❤", s);
Run

Returns a copy of this string where each character is mapped to its ASCII lower case equivalent.

ASCII letters ‘A’ to ‘Z’ are mapped to ‘a’ to ‘z’, but non-ASCII letters are unchanged.

To lowercase the value in-place, use OsStr::make_ascii_lowercase.

Examples

use std::ffi::OsString;
let s = OsString::from("Grüße, Jürgen ❤");

assert_eq!("grüße, jürgen ❤", s.to_ascii_lowercase());
Run

Returns a copy of this string where each character is mapped to its ASCII upper case equivalent.

ASCII letters ‘a’ to ‘z’ are mapped to ‘A’ to ‘Z’, but non-ASCII letters are unchanged.

To uppercase the value in-place, use OsStr::make_ascii_uppercase.

Examples

use std::ffi::OsString;
let s = OsString::from("Grüße, Jürgen ❤");

assert_eq!("GRüßE, JüRGEN ❤", s.to_ascii_uppercase());
Run

Checks if all characters in this string are within the ASCII range.

Examples

use std::ffi::OsString;

let ascii = OsString::from("hello!\n");
let non_ascii = OsString::from("Grüße, Jürgen ❤");

assert!(ascii.is_ascii());
assert!(!non_ascii.is_ascii());
Run

Checks that two strings are an ASCII case-insensitive match.

Same as to_ascii_lowercase(a) == to_ascii_lowercase(b), but without allocating and copying temporaries.

Examples

use std::ffi::OsString;

assert!(OsString::from("Ferris").eq_ignore_ascii_case("FERRIS"));
assert!(OsString::from("Ferrös").eq_ignore_ascii_case("FERRöS"));
assert!(!OsString::from("Ferrös").eq_ignore_ascii_case("FERRÖS"));
Run

Trait Implementations

Performs the conversion.

Performs the conversion.

Immutably borrows from an owned value. Read more

Returns a copy of the value. Read more

Performs copy-assignment from source. Read more

Formats the value using the given formatter. Read more

Constructs an empty OsString.

The resulting type after dereferencing.

Dereferences the value.

Mutably dereferences the value.

Extends a collection with the contents of an iterator. Read more

🔬 This is a nightly-only experimental API. (extend_one #72631)

Extends a collection with exactly one element.

🔬 This is a nightly-only experimental API. (extend_one #72631)

Reserves capacity in a collection for the given number of additional elements. Read more

Extends a collection with the contents of an iterator. Read more

🔬 This is a nightly-only experimental API. (extend_one #72631)

Extends a collection with exactly one element.

🔬 This is a nightly-only experimental API. (extend_one #72631)

Reserves capacity in a collection for the given number of additional elements. Read more

Extends a collection with the contents of an iterator. Read more

🔬 This is a nightly-only experimental API. (extend_one #72631)

Extends a collection with exactly one element.

🔬 This is a nightly-only experimental API. (extend_one #72631)

Reserves capacity in a collection for the given number of additional elements. Read more

Performs the conversion.

Performs the conversion.

Converts a Box<OsStr> into an OsString without copying or allocating.

Performs the conversion.

Converts a OsString into a Box<OsStr> without copying or allocating.

Converts a OsString into a Arc<OsStr> without copying or allocating.

Converts a OsString into a Rc<OsStr> without copying or allocating.

Performs the conversion.

Converts an OsString into a PathBuf

This conversion does not allocate or copy memory.

Converts a PathBuf into an OsString

This conversion does not allocate or copy memory.

Converts a String into a OsString.

This conversion does not allocate or copy memory.

Creates a value from an iterator. Read more

Creates a value from an iterator. Read more

Creates a value from an iterator. Read more

The associated error which can be returned from parsing.

Parses a string s to return a value of this type. Read more

Feeds this value into the given Hasher. Read more

Feeds a slice of this type into the given Hasher. Read more

The returned type after indexing.

Performs the indexing (container[index]) operation. Read more

Performs the mutable indexing (container[index]) operation. Read more

This method returns an Ordering between self and other. Read more

Compares and returns the maximum of two values. Read more

Compares and returns the minimum of two values. Read more

Restrict a value to a certain interval. Read more

Creates an OsString from a byte vector. Read more

Yields the underlying byte vector of this OsString. Read more

Creates an OsString from a byte vector. Read more

Yields the underlying byte vector of this OsString. Read more

Creates an OsString from a potentially ill-formed UTF-16 slice of 16-bit code units. Read more

This method tests for self and other values to be equal, and is used by ==. Read more

This method tests for !=.

This method tests for self and other values to be equal, and is used by ==. Read more

This method tests for !=.

This method tests for self and other values to be equal, and is used by ==. Read more

This method tests for !=.

This method tests for self and other values to be equal, and is used by ==. Read more

This method tests for !=.

This method tests for self and other values to be equal, and is used by ==. Read more

This method tests for !=.

This method tests for self and other values to be equal, and is used by ==. Read more

This method tests for !=.

This method tests for self and other values to be equal, and is used by ==. Read more

This method tests for !=.

This method tests for self and other values to be equal, and is used by ==. Read more

This method tests for !=.

This method tests for self and other values to be equal, and is used by ==. Read more

This method tests for !=.

This method tests for self and other values to be equal, and is used by ==. Read more

This method tests for !=.

This method tests for self and other values to be equal, and is used by ==. Read more

This method tests for !=.

This method tests for self and other values to be equal, and is used by ==. Read more

This method tests for !=.

This method tests for self and other values to be equal, and is used by ==. Read more

This method tests for !=.

This method tests for self and other values to be equal, and is used by ==. Read more

This method tests for !=.

This method tests for self and other values to be equal, and is used by ==. Read more

This method tests for !=.

This method tests for self and other values to be equal, and is used by ==. Read more

This method tests for !=.

This method tests for self and other values to be equal, and is used by ==. Read more

This method tests for !=.

This method tests for self and other values to be equal, and is used by ==. Read more

This method tests for !=.

This method tests for self and other values to be equal, and is used by ==. Read more

This method tests for !=.

This method returns an ordering between self and other values if one exists. Read more

This method tests less than (for self and other) and is used by the < operator. Read more

This method tests less than or equal to (for self and other) and is used by the <= operator. Read more

This method tests greater than (for self and other) and is used by the > operator. Read more

This method tests greater than or equal to (for self and other) and is used by the >= operator. Read more

This method returns an ordering between self and other values if one exists. Read more

This method tests less than (for self and other) and is used by the < operator. Read more

This method tests less than or equal to (for self and other) and is used by the <= operator. Read more

This method tests greater than (for self and other) and is used by the > operator. Read more

This method tests greater than or equal to (for self and other) and is used by the >= operator. Read more

This method returns an ordering between self and other values if one exists. Read more

This method tests less than (for self and other) and is used by the < operator. Read more

This method tests less than or equal to (for self and other) and is used by the <= operator. Read more

This method tests greater than (for self and other) and is used by the > operator. Read more

This method tests greater than or equal to (for self and other) and is used by the >= operator. Read more

This method returns an ordering between self and other values if one exists. Read more

This method tests less than (for self and other) and is used by the < operator. Read more

This method tests less than or equal to (for self and other) and is used by the <= operator. Read more

This method tests greater than (for self and other) and is used by the > operator. Read more

This method tests greater than or equal to (for self and other) and is used by the >= operator. Read more

This method returns an ordering between self and other values if one exists. Read more

This method tests less than (for self and other) and is used by the < operator. Read more

This method tests less than or equal to (for self and other) and is used by the <= operator. Read more

This method tests greater than (for self and other) and is used by the > operator. Read more

This method tests greater than or equal to (for self and other) and is used by the >= operator. Read more

This method returns an ordering between self and other values if one exists. Read more

This method tests less than (for self and other) and is used by the < operator. Read more

This method tests less than or equal to (for self and other) and is used by the <= operator. Read more

This method tests greater than (for self and other) and is used by the > operator. Read more

This method tests greater than or equal to (for self and other) and is used by the >= operator. Read more

This method returns an ordering between self and other values if one exists. Read more

This method tests less than (for self and other) and is used by the < operator. Read more

This method tests less than or equal to (for self and other) and is used by the <= operator. Read more

This method tests greater than (for self and other) and is used by the > operator. Read more

This method tests greater than or equal to (for self and other) and is used by the >= operator. Read more

This method returns an ordering between self and other values if one exists. Read more

This method tests less than (for self and other) and is used by the < operator. Read more

This method tests less than or equal to (for self and other) and is used by the <= operator. Read more

This method tests greater than (for self and other) and is used by the > operator. Read more

This method tests greater than or equal to (for self and other) and is used by the >= operator. Read more

This method returns an ordering between self and other values if one exists. Read more

This method tests less than (for self and other) and is used by the < operator. Read more

This method tests less than or equal to (for self and other) and is used by the <= operator. Read more

This method tests greater than (for self and other) and is used by the > operator. Read more

This method tests greater than or equal to (for self and other) and is used by the >= operator. Read more

This method returns an ordering between self and other values if one exists. Read more

This method tests less than (for self and other) and is used by the < operator. Read more

This method tests less than or equal to (for self and other) and is used by the <= operator. Read more

This method tests greater than (for self and other) and is used by the > operator. Read more

This method tests greater than or equal to (for self and other) and is used by the >= operator. Read more

This method returns an ordering between self and other values if one exists. Read more

This method tests less than (for self and other) and is used by the < operator. Read more

This method tests less than or equal to (for self and other) and is used by the <= operator. Read more

This method tests greater than (for self and other) and is used by the > operator. Read more

This method tests greater than or equal to (for self and other) and is used by the >= operator. Read more

This method returns an ordering between self and other values if one exists. Read more

This method tests less than (for self and other) and is used by the < operator. Read more

This method tests less than or equal to (for self and other) and is used by the <= operator. Read more

This method tests greater than (for self and other) and is used by the > operator. Read more

This method tests greater than or equal to (for self and other) and is used by the >= operator. Read more

This method returns an ordering between self and other values if one exists. Read more

This method tests less than (for self and other) and is used by the < operator. Read more

This method tests less than or equal to (for self and other) and is used by the <= operator. Read more

This method tests greater than (for self and other) and is used by the > operator. Read more

This method tests greater than or equal to (for self and other) and is used by the >= operator. Read more

This method returns an ordering between self and other values if one exists. Read more

This method tests less than (for self and other) and is used by the < operator. Read more

This method tests less than or equal to (for self and other) and is used by the <= operator. Read more

This method tests greater than (for self and other) and is used by the > operator. Read more

This method tests greater than or equal to (for self and other) and is used by the >= operator. Read more

This method returns an ordering between self and other values if one exists. Read more

This method tests less than (for self and other) and is used by the < operator. Read more

This method tests less than or equal to (for self and other) and is used by the <= operator. Read more

This method tests greater than (for self and other) and is used by the > operator. Read more

This method tests greater than or equal to (for self and other) and is used by the >= operator. Read more

This method returns an ordering between self and other values if one exists. Read more

This method tests less than (for self and other) and is used by the < operator. Read more

This method tests less than or equal to (for self and other) and is used by the <= operator. Read more

This method tests greater than (for self and other) and is used by the > operator. Read more

This method tests greater than or equal to (for self and other) and is used by the >= operator. Read more

Auto Trait Implementations

Blanket Implementations

Gets the TypeId of self. Read more

Immutably borrows from an owned value. Read more

Mutably borrows from an owned value. Read more

Performs the conversion.

Performs the conversion.

The resulting type after obtaining ownership.

Creates owned data from borrowed data, usually by cloning. Read more

🔬 This is a nightly-only experimental API. (toowned_clone_into #41263)

recently added

Uses borrowed data to replace owned data, usually by cloning. Read more

The type returned in the event of a conversion error.

Performs the conversion.

The type returned in the event of a conversion error.

Performs the conversion.