WIP: Tryouts on a fix command.

cargo-scout-lib/src/error.rs

@@ -18,4 +18,6 @@ pub enum Error {
     Io(#[from] std::io::Error),
     #[error("Git error: {0}")]
     Git(#[from] git2::Error),
+    #[error("The provided command is invalid.")]
+    InvalidCommand,
 }

cargo-scout-lib/src/healer/mod.rs

@@ -0,0 +1,5 @@
+use crate::linter::Lint;
+
+pub trait Healer {
+    fn heal(&self, lints: Vec<Lint>) -> Result<(), crate::error::Error>;
+}

cargo-scout-lib/src/lib.rs

@@ -1,5 +1,6 @@
 pub mod config;
 pub mod error;
+pub mod healer;
 pub mod linter;
 pub mod scout;
 pub mod vcs;

cargo-scout-lib/src/linter/mod.rs

@@ -1,3 +1,4 @@
+use serde::Serialize;
 use std::path::PathBuf;
 
 pub mod clippy;
@@ -21,7 +22,7 @@ pub struct Lint {
 }
 
 /// A `Location` has a file name, a start and an end line
-#[derive(PartialEq, Clone, Debug)]
+#[derive(Serialize, PartialEq, Clone, Debug)]
 pub struct Location {
     pub path: String,
     pub lines: [u32; 2],

cargo-scout-lib/src/linter/rustfmt.rs

@@ -1,4 +1,5 @@
 use crate::error::Error;
+use crate::healer::Healer;
 use crate::linter::{Lint, Linter, Location};
 use crate::utils::get_absolute_file_path;
 use serde::Deserialize;
@@ -21,6 +22,24 @@ impl Linter for RustFmt {
     }
 }
 
+impl Healer for RustFmt {
+    fn heal(&self, lints: Vec<Lint>) -> Result<(), crate::error::Error> {
+        Command::new("rustfmt").args(&[
+            "--unstable-features",
+            "--file-lines",
+            &lints_as_json(&lints)?,
+            "--skip-children",
+            "--edition=2018",
+        ]);
+        Ok(())
+    }
+}
+
+fn lints_as_json(lints: &[Lint]) -> Result<String, crate::error::Error> {
+    let locations: Vec<Location> = lints.iter().map(|l| l.location.clone()).collect();
+    Ok(serde_json::to_string(&locations)?)
+}
+
 impl RustFmt {
     fn command_parameters() -> Vec<&'static str> {
         vec!["+nightly", "fmt", "--", "--emit", "json"]

cargo-scout-lib/src/scout/mod.rs

@@ -1,4 +1,5 @@
 use crate::config::*;
+use crate::healer::Healer;
 use crate::linter::{Lint, Linter};
 use crate::vcs::*;
 use std::path::PathBuf;
@@ -47,6 +48,26 @@ where
     }
 }
 
+pub struct Fixer<H>
+where
+    H: Healer,
+{
+    medic: H,
+}
+
+impl<H> Fixer<H>
+where
+    H: Healer,
+{
+    pub fn new(medic: H) -> Self {
+        Self { medic }
+    }
+    pub fn run(&self, lints: Vec<Lint>) -> Result<(), crate::error::Error> {
+        println!("[Scout] - applying fixes");
+        self.medic.heal(lints)
+    }
+}
+
 fn diff_in_member(member: &PathBuf, sections: &[Section]) -> bool {
     if let Some(m) = member.to_str() {
         for s in sections {

cargo-scout/src/main.rs

@@ -1,4 +1,5 @@
 use cargo_scout_lib::config::rust::CargoConfig;
+use cargo_scout_lib::fixer::Fixer;
 use cargo_scout_lib::linter::clippy::Clippy;
 use cargo_scout_lib::linter::rustfmt::RustFmt;
 use cargo_scout_lib::linter::Lint;
@@ -15,6 +16,12 @@ use structopt::StructOpt;
 )]
 enum Command {
     Fmt(FmtOptions),
+    Fix(FixCommand),
+    Lint(LintOptions),
+}
+
+#[derive(StructOpt)]
+enum FixCommand {
     Lint(LintOptions),
 }
 
@@ -74,11 +81,29 @@ struct LintOptions {
 #[cfg_attr(tarpaulin, skip)]
 fn main() -> Result<(), Error> {
     match Command::from_args() {
+        Command::Fix(opts) => run_fix(opts),
         Command::Fmt(opts) => run_fmt(opts),
         Command::Lint(opts) => run_lint(opts),
     }
 }
 
+#[cfg_attr(tarpaulin, skip)]
+#[allow(irrefutable_let_patterns)]
+fn run_fix(fix_command: FixCommand) -> Result<(), Error> {
+    if let FixCommand::Lint(opts) = fix_command {
+        let vcs = Git::with_target(opts.branch);
+        let config = CargoConfig::from_manifest_path(opts.cargo_toml)?;
+        let linter = RustFmt::default();
+
+        let scout = Scout::new(vcs, config, linter); // TODO: do not consume?
+        let relevant_lints = scout.run()?;
+        let fixer = RustFmt::default();
+        fixer.fix(relevant_lints)?
+    }
+
+    Err(Error::InvalidCommand)
+}
+
 #[cfg_attr(tarpaulin, skip)]
 fn run_lint(opts: LintOptions) -> Result<(), Error> {
     let fail_if_errors = opts.without_error;