cargo dev crater: lay out the base plan

clippy_dev/src/crater.rs

@@ -0,0 +1,69 @@
+use std::path::PathBuf;
+use std::process::Command;
+
+// represents an archive we download from crates.io
+struct KrateSource {
+    version: String,
+    name: String,
+}
+
+// represents the extracted sourcecode of a crate
+struct Krate {
+    version: String,
+    name: String,
+}
+
+impl KrateSource {
+    fn new(version: &str, name: &str) -> Self {
+        KrateSource {
+            version: version.into(),
+            name: name.into(),
+        }
+    }
+    fn download_and_extract(self) -> Krate {
+        // download
+        // extract
+
+        Krate {
+            version: self.version,
+            name: self.name,
+        }
+    }
+}
+
+impl Krate {
+    fn run_clippy_lints(&self) -> String {
+        todo!();
+    }
+
+
+}
+
+fn build_clippy() {
+    Command::new("cargo")
+        .arg("build")
+        .output()
+        .expect("Failed to build clippy!");
+}
+
+// the main fn
+pub(crate) fn run() {
+    let cargo_clippy_path: PathBuf = PathBuf::from("target/debug/cargo-clippy");
+    let clippy_driver_path: PathBuf = PathBuf::from("target/debug/cargo-driver");
+
+    // crates we want to check:
+    let krates: Vec<KrateSource> = vec![KrateSource::new("cargo", "0.49.0"), KrateSource::new("regex", "1.4.2")];
+
+    build_clippy();
+    // assert that clippy is found
+    assert!(
+        cargo_clippy_path.is_file(),
+        "target/debug/cargo-clippy binary not found!"
+    );
+    assert!(
+        clippy_driver_path.is_file(),
+        "target/debug/clippy-driver binary not found!"
+    );
+
+  let clippy_lint_results: Vec<String> = krates.into_iter().map(|krate|  krate.download_and_extract()).map(|krate| krate.run_clippy_lints()).collect::<Vec<String>>();
+}

clippy_dev/src/lib.rs

@@ -11,6 +11,7 @@ use std::path::{Path, PathBuf};
 use walkdir::WalkDir;
 
 pub mod bless;
+pub mod crater;
 pub mod fmt;
 pub mod new_lint;
 pub mod ra_setup;