Struct HakariCargoToml

pub struct HakariCargoToml { /* private fields */ }

Support for maintaining Cargo.toml files that unify features in a workspace.

This struct maintains a context around a Cargo.toml file. It provides facilities for diffing the contents of the file, and for writing out new contents.

Structure of the Cargo.toml file

The Cargo.toml file is treated as partially generated. It is expected to have a section marked off as, for example:

[package]
...

### BEGIN HAKARI SECTION
[dependencies]
...

[build-dependencies]
...

[dev-dependencies]
...
### END HAKARI SECTION

The part of the Cargo.toml file between the BEGIN HAKARI SECTION and END HAKARI SECTION lines is managed by this struct, and changes to it may not be preserved. The part of the file outside this section can be edited and its contents will be preserved.

Setting up a new package

For Hakari to manage a package, a bit of initial prep work must be done:

1. Add a new library package in a desired location within your workspace, for example: cargo new --lib hakari-package.

2. Copy and paste the following lines of code to the end of the package’s Cargo.toml file. Be sure to put in a trailing newline.

   ### BEGIN HAKARI SECTION
   
   ### END HAKARI SECTION
   

3. Add an empty build.rs file (the exact contents don’t matter, but the presence of this file makes build dependencies work properly).

   fn main() {}

Implementations

impl HakariCargoToml

pub const BEGIN_SECTION: &'static str = "\n### BEGIN HAKARI SECTION\n"

The string "\n### BEGIN HAKARI SECTION\n". This string marks the beginning of the generated section.

pub const END_SECTION: &'static str = "\n### END HAKARI SECTION\n"

The string "\n### END HAKARI SECTION\n". This string marks the end of the generated section.

pub fn new(toml_path: impl Into<Utf8PathBuf>) -> Result<Self, CargoTomlError>

Creates a new instance of HakariCargoToml with the Cargo.toml located at the given path. Reads the contents of the file off of disk.

If the path is relative, it is evaluated with respect to the current directory.

Returns an error if the file couldn’t be read (other than if the file wasn’t found, which is a case handled by this struct).

pub fn new_relative( workspace_root: impl Into<Utf8PathBuf>, crate_dir: impl AsRef<Utf8Path>, ) -> Result<Self, CargoTomlError>

Creates a new instance of HakariCargoToml at the given workspace root and crate directory. Reads the contents of the file off of disk.

This is a convenience method around appending crate_dir and Cargo.toml to workspace_root.

If the path is relative, it is evaluated with respect to the current directory.

pub fn new_in_memory( toml_path: impl Into<Utf8PathBuf>, contents: String, ) -> Result<Self, CargoTomlError>

Creates a new instance of HakariCargoToml with the given path with the given contents as read from disk.

This may be useful for test scenarios.

pub fn toml_path(&self) -> &Utf8Path

Returns the toml path provided at construction time.

pub fn contents(&self) -> &str

Returns the contents of the file on disk as read at construction time.

pub fn generated_offsets(&self) -> (usize, usize)

Returns the start and end offsets of the part of the file treated as generated.

pub fn generated_contents(&self) -> &str

Returns the part of the file that is treated as generated.

This part of the file will be replaced on write.

pub fn is_changed(&self, toml: &str) -> bool

Returns true if the contents on disk are different from the provided TOML output.

pub fn diff_toml<'a>(&'a self, toml: &'a str) -> Patch<'a, str>

Computes the diff between the contents on disk and the provided TOML output.

This returns a diffy::Patch, which can be formatted through methods provided by diffy. diffy is re-exported at the top level of this crate.

Examples

TODO

pub fn write_to_file(self, toml: &str) -> Result<bool, CargoTomlError>

Writes out the provided TOML to the generated section of the file. The rest of the file is left unmodified.

self is consumed because the contents of the file are now assumed to be invalid.

Returns true if the contents were different and the file was written out, false if the contents were the same and the file was not written out, and an error if there was an issue while writing the file out.

pub fn write(&self, toml: &str, out: impl Write) -> Result<()>

Writes out the full contents, including the provided TOML, to the given writer.

pub fn write_to_fmt(&self, toml: &str, out: impl Write) -> Result

Writes out the full contents, including the provided TOML, to the given fmt::Write instance.

std::io::Write expects bytes to be written to it, so using it with a &mut String is inconvenient. This alternative is more convenient, and also works for fmt::Formatter instances.

Trait Implementations

impl Clone for HakariCargoToml

fn clone(&self) -> HakariCargoToml

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for HakariCargoToml

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

Formats the value using the given formatter.