Enum cargo::util::cache_lock::CacheLockMode

pub enum CacheLockMode {
    DownloadExclusive,
    Shared,
    MutateExclusive,
}

The style of lock to acquire.

Variants

DownloadExclusive

A DownloadExclusive lock ensures that only one cargo is doing resolution and downloading new packages.

You should use this when downloading new packages or doing resolution.

If another cargo has a MutateExclusive lock, then an attempt to get a DownloadExclusive lock will block.

If another cargo has a Shared lock, then both can operate concurrently.

Shared

A Shared lock allows multiple cargos to read from the source files.

You should use this when cargo is reading source files from the package cache. This is typically done during the build phase, since cargo only needs to read files during that time. This allows multiple cargo processes to build concurrently without interfering with one another, while guarding against other cargos using MutateExclusive.

If another cargo has a MutateExclusive lock, then an attempt to get a Shared will block.

If another cargo has a DownloadExclusive lock, then they both can operate concurrently under the assumption that downloading does not modify existing source files.

MutateExclusive

A MutateExclusive lock ensures no other cargo is reading or writing from the package caches.

You should use this when modifying existing files in the package cache. For example, things like garbage collection want to avoid deleting files while other cargos are trying to read (Shared) or resolve or download (DownloadExclusive).

If another cargo has a DownloadExclusive or Shared lock, then this will block until they all release their locks.

Trait Implementations

impl Clone for CacheLockMode

fn clone(&self) -> CacheLockMode

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for CacheLockMode

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

Formats the value using the given formatter.

impl PartialEq for CacheLockMode

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

Tests for self and other values to be equal, and is used by ==.

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

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Copy for CacheLockMode

impl StructuralPartialEq for CacheLockMode

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: 1 byte

Size for each variant:

• DownloadExclusive: 0 bytes
• Shared: 0 bytes
• MutateExclusive: 0 bytes