Module guppy::platform

Expand description

Support for dependencies that are only enabled on some platforms.

Most of the time, dependencies are enabled across all platforms. For example, in this Cargo.toml:

[dependencies]
once_cell = "1.5"

However, in some cases, dependencies may only be enabled on certain platforms.

[target.x86_64-unknown-linux-gnu.dependencies]
inotify = "0.9.4"

[target.'cfg(windows)'.build-dependencies]
winapi = "0.3.9"

This module provides types that can represent platforms and evaluate expressions.

Representing platforms

Platform represents a single platform.
Triple is a Rust target triple.
PlatformSpec represents a single platform or a range of platforms, including any platform (the union of all possible platforms) and all platforms (the intersection of all possible platforms).

Evaluating platforms

These structs are defined in the context of a PackageGraph, and are typically returned through PackageLink instances.

PlatformStatus: The status of a dependency or a feature which might be platform-dependent.
PlatformEval: A collection of platform specifications like cfg(unix), to evaluate against a platform.
EnabledTernary: A three-valued logic representing the status of a dependency or feature on a given platform. Includes an additional status to represent situations like unknown target features.

If the summaries feature is enabled, this module also supports reading and writing serializable summaries of platforms. These can be used both as configuration, and to serialize the results of a particular guppy evaluation.

For more, about platform-specific dependencies, see Platform specific dependencies in the Cargo reference.