From 4c22f1cc89c0704ec705ef292583e17d9d9f5ed4 Mon Sep 17 00:00:00 2001
From: "Dr. Matthias Ratajczak" <m.ratajczak@hzdr.de>
Date: Thu, 5 Jan 2023 17:25:39 +0100
Subject: [PATCH] add cargo backend

---
 src/backend/mod.rs    | 13 +++++---
 src/backend/pacman.rs |  8 ++---
 src/backend/rust.rs   | 76 +++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 88 insertions(+), 9 deletions(-)
 create mode 100644 src/backend/rust.rs

diff --git a/src/backend/mod.rs b/src/backend/mod.rs
index cd31145..d4acaf8 100644
--- a/src/backend/mod.rs
+++ b/src/backend/mod.rs
@@ -1,4 +1,5 @@
 mod pacman;
+mod rust;
 
 use std::collections::HashSet;
 use std::os::unix::process::CommandExt;
@@ -7,16 +8,18 @@ use std::process::Command;
 use crate::Package;
 
 pub use pacman::Pacman;
+type Switches = &'static [&'static str];
+type Binary = &'static str;
 
 pub trait Backend {
     /// The binary that should be called to run the associated package manager.
-    const BINARY: &'static str;
+    const BINARY: Binary;
 
     /// The switches that signals the `BINARY` that the packages should be installed.
-    const SWITCH_INSTALL: &'static str;
+    const SWITCHES_INSTALL: Switches;
 
     /// The switches that signals the `BINARY` that the packages should be removed.
-    const SWITCH_REMOVE: &'static str;
+    const SWITCHES_REMOVE: Switches;
 
     /// Get all packages that are installed in the system.
     fn get_all_installed_packages() -> HashSet<Package>;
@@ -27,7 +30,7 @@ pub trait Backend {
     /// Install the specified packages.
     fn install_packages(packages: Vec<Package>) {
         let mut cmd = Command::new(Self::BINARY);
-        cmd.arg(Self::SWITCH_INSTALL);
+        cmd.args(Self::SWITCHES_INSTALL);
         for p in packages {
             cmd.arg(format!("{p}"));
         }
@@ -37,7 +40,7 @@ pub trait Backend {
     /// Remove the specified packages.
     fn remove_packages(packages: Vec<Package>) {
         let mut cmd = Command::new(Self::BINARY);
-        cmd.arg(Self::SWITCH_REMOVE);
+        cmd.args(Self::SWITCHES_REMOVE);
         for p in packages {
             cmd.arg(format!("{p}"));
         }
diff --git a/src/backend/pacman.rs b/src/backend/pacman.rs
index 0958fd4..1309159 100644
--- a/src/backend/pacman.rs
+++ b/src/backend/pacman.rs
@@ -3,15 +3,15 @@ use std::collections::HashSet;
 use alpm::Alpm;
 use alpm::PackageReason::Explicit;
 
-use super::Backend;
+use super::{Backend, Binary, Switches};
 use crate::Package;
 
 pub struct Pacman;
 
 impl Backend for Pacman {
-    const BINARY: &'static str = "paru";
-    const SWITCH_INSTALL: &'static str = "-S";
-    const SWITCH_REMOVE: &'static str = "-Rsn";
+    const BINARY: Binary = "paru";
+    const SWITCHES_INSTALL: Switches = &["-S"];
+    const SWITCHES_REMOVE: Switches = &["-Rsn"];
 
     fn get_all_installed_packages() -> HashSet<Package> {
         convert_to_pacdef_packages(get_all_installed_packages_from_alpm())
diff --git a/src/backend/rust.rs b/src/backend/rust.rs
new file mode 100644
index 0000000..3d9a501
--- /dev/null
+++ b/src/backend/rust.rs
@@ -0,0 +1,76 @@
+use std::{collections::HashSet, process::Command};
+
+use super::{Backend, Binary, Switches};
+use crate::Package;
+
+pub struct Rust;
+
+impl Backend for Rust {
+    const BINARY: Binary = "cargo";
+    const SWITCHES_INSTALL: Switches = &["install"];
+    const SWITCHES_REMOVE: Switches = &["uninstall"];
+
+    fn get_all_installed_packages() -> HashSet<Package> {
+        extract_packages_names(&run_cargo_install_list())
+            .map(Package::from)
+            .collect()
+    }
+
+    fn get_explicitly_installed_packages() -> HashSet<Package> {
+        Self::get_all_installed_packages()
+    }
+}
+
+fn run_cargo_install_list() -> String {
+    let stdout = Command::new("cargo")
+        .args(["install", "--list"])
+        .output()
+        .unwrap()
+        .stdout;
+    String::from_utf8(stdout).unwrap()
+}
+
+fn extract_packages_names(output: &str) -> impl Iterator<Item = String> + '_ {
+    output
+        .lines()
+        .filter(|line| !line.starts_with(char::is_whitespace))
+        .map(|line| line.split_whitespace().next().unwrap().to_owned())
+}
+
+#[cfg(test)]
+mod tests {
+    use super::extract_packages_names;
+
+    #[test]
+    fn test_extract_packages() {
+        const OUTPUT: &str = "cargo-audit v0.17.4:
+    cargo-audit
+cargo-cache v0.8.3:
+    cargo-cache
+cargo-criterion v1.1.0:
+    cargo-criterion
+cargo-update v11.1.1:
+    cargo-install-update
+    cargo-install-update-config
+flamegraph v0.6.2:
+    cargo-flamegraph
+    flamegraph
+topgrade v10.1.2 (/home/ratajc72/tmp/topgrade):
+    topgrade
+wthrr v0.6.1:
+    wthrr";
+        let extracted: Vec<String> = extract_packages_names(OUTPUT).collect();
+        assert_eq!(
+            &extracted,
+            &[
+                "cargo-audit",
+                "cargo-cache",
+                "cargo-criterion",
+                "cargo-update",
+                "flamegraph",
+                "topgrade",
+                "wthrr"
+            ]
+        );
+    }
+}