pub struct Memory { /* private fields */ }
Expand description

A hash-like accessor for environment variables using a fake in-memory store.

Memory offers the same API as other environment variable backends in this crate, but does not access or mutate the underlying system.

This backend is suitable for running in untrusted environments such as a Wasm binary, testing environments, or in embedded contexts.

Examples

Fetching an environment variable:

let env = Memory::new();
// `Memory` backends are initially empty.
assert_eq!(env.get(b"PATH"), Ok(None));

Setting an environment variable:

let mut env = Memory::new();
env.put(b"ENV_BACKEND", Some(b"spinoso_env::Memory"))?;
assert_eq!(env.get(b"ENV_BACKEND")?.as_deref(), Some(&b"spinoso_env::Memory"[..]));

Implementations

Constructs a new, empty ENV Memory backend.

The resulting environment variable accessor has no access to the underlying host operating system. The returned accessor uses a virtual environment.

Examples
let env = Memory::new();

Retrieves the value for environment variable name.

Returns None if the named variable does not exist.

Examples
let env = Memory::new();
assert_eq!(env.get(b"PATH"), Ok(None));
Errors

If name contains a NUL byte, e.g. b'\0', an error is returned.

Sets the environment variable name to value.

If the value given is None the environment variable is deleted.

Examples
let mut env = Memory::new();

env.put(b"RUBY", Some(b"Artichoke"))?;
assert_eq!(env.get(b"RUBY")?.as_deref(), Some(&b"Artichoke"[..]));

env.put(b"RUBY", None)?;
assert_eq!(env.get(b"RUBY")?, None);
Errors

If name contains a NUL byte, e.g. b'\0', an argument error is returned.

If name contains an ‘=’ byte, e.g. b'=', an EINVAL error is returned.

If value is Some and contains a NUL byte, e.g. b'\0', an argument error is returned.

Serialize the environ to a HashMap.

Map keys are environment variable names and map values are environment variable values.

Examples
let env = Memory::new();
let map = env.to_map()?;
assert!(map.is_empty());
Errors

This function is infallible.

Trait Implementations

Returns a copy of the value. Read more
Performs copy-assignment from source. Read more
Formats the value using the given formatter. Read more
Returns the “default value” for a type. Read more
This method tests for self and other values to be equal, and is used by ==. Read more
This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason. 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

Returns the argument unchanged.

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

The resulting type after obtaining ownership.
Creates owned data from borrowed data, usually by cloning. Read more
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.