Enum EnvPrecedence 

#[non_exhaustive]
pub enum EnvPrecedence {
    BeforeSystem,
    AfterSystem,
}

Where the process environment ranks against the OS settings in ProxyConfig::with_env.

A third ranking, “ignore the environment”, is deliberately not a variant here: a caller who wants the environment ignored does not call with_env.

Variants (Non-exhaustive)

Non-exhaustive enums could have additional variants added in future. Therefore, when matching against variants of non-exhaustive enums, an extra wildcard arm must be added to account for any future variants.

BeforeSystem

The environment outranks every OS source. What a consumer layering a *_proxy reader over the system settings gets by default — Go’s golang.org/x/net/http/ httpproxy reads the variables and nothing else, so a caller who consults it first has already chosen this.

AfterSystem

The OS settings outrank the environment, which answers only when they produced no configuration at all. Not per scheme: one OS source is enough to settle every scheme, including the ones it says nothing about — ProxyConfig::with_env ranks sources, it does not fill slots. Chromium’s net/proxy_resolution/proxy_config_service_linux.cc does this in the strong form — once the desktop settings have produced a configuration it never looks at the variables, a desktop mode of “none” counts as one, and reading mode always finds a value, so a stock desktop nobody has ever configured still counts.

This crate is deliberately a shade weaker on GNOME: it asks who wrote that mode, and only one somebody actually set — the user’s dconf layer, or an administrator’s profile — becomes a source. A machine where nobody has opened the proxy settings therefore reaches this rank with an empty sources, and the environment answers. “Nobody configured anything” and “somebody chose direct” are different answers, and only the second should outrank a *_proxy an operator set on purpose.

On Windows that leaves this a rank the environment never takes: read always reports a Registry source, ProxyEnable = 0 included, so there is never a snapshot for the environment to answer for. macOS is nearly as closed: a scope the reader could interpret becomes a source whatever it says, Direct included, so the environment answers only where neither State: nor Setup: came back — a missing key, a NULL, or a value that is not a dictionary — and not merely where the scopes name no proxy. Linux is where this rank earns its keep: desktop stores that exist and are unset produce a snapshot with no source at all. So does the degraded case beside it — the store this session’s desktop would normally use compiled out of the build while the other one is unset — where the empty sources means “never consulted” rather than “found nothing”, which only fallbacks records. A machine with no desktop store at all is not this case: read fails with Error::Unsupported, so there is no snapshot to fold an environment into.

A rank the environment never takes is still not the “ignore” this enum leaves out, which is a caller not folding at all. What a rank settles is effective; the rest of the fold happens either way, so the environment lands in sources and captured_at drops to the older of the two reads even where this one can never win.

Trait Implementations

impl Clone for EnvPrecedence

fn clone(&self) -> EnvPrecedence

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Copy for EnvPrecedence

impl Debug for EnvPrecedence

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

Formats the value using the given formatter.

impl Eq for EnvPrecedence

impl Hash for EnvPrecedence

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl Ord for EnvPrecedence

fn cmp(&self, other: &EnvPrecedence) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized,

Restrict a value to a certain interval.

fn clamp_to<R>(self, range: R) -> Self

where Self: Sized, R: ClampBounds<Self>,

🔬This is a nightly-only experimental API. (clamp_to)

Restrict a value to a certain range.

impl PartialEq for EnvPrecedence

fn eq(&self, other: &EnvPrecedence) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl PartialOrd for EnvPrecedence

fn partial_cmp(&self, other: &EnvPrecedence) -> Option<Ordering>

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

fn lt(&self, other: &Rhs) -> bool

Tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &Rhs) -> bool

Tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &Rhs) -> bool

Tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &Rhs) -> bool

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl StructuralPartialEq for EnvPrecedence