Struct Env

pub struct Env {
    env: HashMap<OsString, OsString>,
    normalized_env: HashMap<String, String>,
    case_insensitive_env: HashMap<String, String>,
}

A snapshot of the environment variables available to GlobalContext.

Currently, the GlobalContext supports lookup of environment variables through two different means:

• GlobalContext::get_env and GlobalContext::get_env_os for process environment variables (similar to std::env::var and std::env::var_os),
• Typed Config Value API via GlobalContext::get. This is only available for CARGO_ prefixed environment keys.

This type contains the env var snapshot and helper methods for both APIs.

Fields

env: HashMap<OsString, OsString>

A snapshot of the process’s environment variables.

normalized_env: HashMap<String, String>

Used in the typed Config value API for warning messages when config keys are given in the wrong format.

Maps from “normalized” (upper case and with “-” replaced by “_”) env keys to the actual keys in the environment. The normalized format is the one expected by Cargo.

This only holds env keys that are valid UTF-8, since super::ConfigKey only supports UTF-8 keys. In addition, this only holds env keys whose value in the environment is also valid UTF-8, since the typed Config value API only supports UTF-8 values.

case_insensitive_env: HashMap<String, String>

Used to implement get_env and get_env_os on Windows, where env keys are case-insensitive.

Maps from uppercased env keys to the actual key in the environment. For example, this might hold a pair ("PATH", "Path"). Currently only supports UTF-8 keys and values.

Implementations

impl Env

pub fn new() -> Self

Create a new Env from process’s environment variables.

pub(super) fn from_map(env: HashMap<String, String>) -> Self

Set the env directly from a HashMap. This should be used for debugging purposes only.

pub fn iter_str(&self) -> impl Iterator<Item = (&str, &str)>

Returns all environment variables as an iterator, keeping only entries where both the key and value are valid UTF-8.

pub fn keys_str(&self) -> impl Iterator<Item = &str>

Returns all environment variable keys, filtering out keys that are not valid UTF-8.

pub fn get_env_os(&self, key: impl AsRef<OsStr>) -> Option<&OsStr>

Get the value of environment variable key through the snapshot in GlobalContext.

This can be used similarly to std::env::var_os. On Windows, we check for case mismatch since environment keys are case-insensitive.

pub fn get_env(&self, key: impl AsRef<OsStr>) -> CargoResult<&str>

Get the value of environment variable key through the self.env snapshot.

This can be used similarly to std::env::var. On Windows, we check for case mismatch since environment keys are case-insensitive.

fn get_env_case_insensitive(&self, key: impl AsRef<OsStr>) -> Option<&OsStr>

Performs a case-insensitive lookup of key in the environment.

This is relevant on Windows, where environment variables are case-insensitive. Note that this only works on keys that are valid UTF-8 and it uses Unicode uppercase, which may differ from the OS’s notion of uppercase.

pub(super) fn get_str(&self, key: impl AsRef<OsStr>) -> Option<&str>

Get the value of environment variable key as a &str. Returns None if key is not in self.env or if the value is not valid UTF-8.

This is intended for use in private methods of GlobalContext, and does not check for env key case mismatch.

This is case-sensitive on Windows (even though environment keys on Windows are usually case-insensitive) due to an unintended regression in 1.28 (via #5552). This should only affect keys used for cargo’s config-system env variables (CARGO_ prefixed ones), which are currently all uppercase. We may want to consider rectifying it if users report issues. One thing that adds a wrinkle here is the unstable advanced-env option that requires case-sensitive keys.

Do not use this for any other purposes. Use Env::get_env_os or Env::get_env instead, which properly handle case insensitivity on Windows.

pub(super) fn contains_key(&self, key: impl AsRef<OsStr>) -> bool

Check if the environment contains key.

This is intended for use in private methods of GlobalContext, and does not check for env key case mismatch. See the docstring of Env::get_str for more context.

pub(super) fn get_normalized(&self, key: &str) -> Option<&str>

Looks up a normalized key in the normalized_env. Returns the corresponding (non-normalized) env key if it exists, else None.

This is used by super::GlobalContext::check_environment_key_case_mismatch.

Trait Implementations

impl Debug for Env

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

Formats the value using the given formatter.

Layout

Note: Most layout information is completely unstable and may even differ between compilations. The only exception is types with certain repr(...) attributes. Please see the Rust Reference's “Type Layout” chapter for details on type layout guarantees.

Size: 144 bytes