rust: replace most "operation" structs with functions
The hg-core crate has a partially-formed concept of "operation",
represented as structs with constructors and a `run` method.
Each struct’s contructor takes different parameters,
and each `run` has a different return type.
Constructors typically don’t do much more than store parameters
for `run` to access them.
There was a comment about adding an `Operation` trait
when the language supports expressing something so general,
but it’s hard to imagine how operations with such different APIs
could be used in a generic context.
This commit starts removing the concept of "operation",
since those are pretty much just functions.
Differential Revision: https://phab.mercurial-scm.org/D9595
use crate::commands::Command;
use crate::error::CommandError;
use crate::ui::Ui;
use hg::operations::find_root;
use hg::requirements;
pub const HELP_TEXT: &str = "
Print the current repo requirements.
";
pub struct DebugRequirementsCommand {}
impl DebugRequirementsCommand {
pub fn new() -> Self {
DebugRequirementsCommand {}
}
}
impl Command for DebugRequirementsCommand {
fn run(&self, ui: &Ui) -> Result<(), CommandError> {
let root = find_root()?;
let mut output = String::new();
for req in requirements::load(&root)? {
output.push_str(&req);
output.push('\n');
}
ui.write_stdout(output.as_bytes())?;
Ok(())
}
}