feat(backend): add fedora / dnf

This series of commits provides support for Fedora Linux and its dnf
package manager.

Implemented in #56. Closes #54.

crates/pacdef_core/src/backend/actual/fedora.rs

@@ -0,0 +1,141 @@
+use std::collections::HashSet;
+use std::process::Command;
+
+use anyhow::Result;
+
+use crate::backend::backend_trait::{Backend, Switches, Text};
+use crate::backend::macros::impl_backend_constants;
+use crate::cmd::run_external_command;
+use crate::{Group, Package};
+
+#[derive(Debug, Clone)]
+pub struct Fedora {
+    pub(crate) packages: HashSet<Package>,
+}
+
+const BINARY: Text = "dnf";
+const SECTION: Text = "fedora";
+
+const SWITCHES_INFO: Switches = &["info"];
+const SWITCHES_INSTALL: Switches = &["install"];
+const SWITCHES_MAKE_DEPENDENCY: Switches = &[];
+const SWITCHES_NOCONFIRM: Switches = &["--assumeyes"];
+const SWITCHES_REMOVE: Switches = &["remove"];
+
+const SUPPORTS_AS_DEPENDENCY: bool = false;
+
+/// These switches are responsible for
+/// getting the packages explicitly installed by the user
+const SWITCHES_FETCH_USER: Switches = &[
+    "repoquery",
+    "--userinstalled",
+    "--queryformat",
+    "%{from_repo}/%{name}",
+];
+
+/// These switches are responsible for
+/// getting all the packages installed on the system
+const SWITCHES_FETCH_GLOBAL: Switches = &[
+    "repoquery",
+    "--installed",
+    "--queryformat",
+    "%{from_repo}/%{name}",
+];
+
+/// These repositories are ignored when storing the packages
+/// as these are present by default on any sane fedora system
+const DEFAULT_REPOS: [&str; 5] = ["koji", "fedora", "updates", "anaconda", "@"];
+
+impl Backend for Fedora {
+    impl_backend_constants!();
+
+    fn get_all_installed_packages(&self) -> Result<HashSet<Package>> {
+        let mut cmd = Command::new(self.get_binary());
+        cmd.args(SWITCHES_FETCH_GLOBAL);
+
+        let output = String::from_utf8(cmd.output()?.stdout)?;
+        let packages = output.lines().map(create_package).collect();
+
+        Ok(packages)
+    }
+
+    fn get_explicitly_installed_packages(&self) -> Result<HashSet<Package>> {
+        let mut cmd = Command::new(self.get_binary());
+        cmd.args(SWITCHES_FETCH_USER);
+
+        let output = String::from_utf8(cmd.output()?.stdout)?;
+        let packages = output.lines().map(create_package).collect();
+
+        Ok(packages)
+    }
+
+    /// Install the specified packages.
+    fn install_packages(&self, packages: &[Package], noconfirm: bool) -> Result<()> {
+        let mut cmd = Command::new("sudo");
+        cmd.arg(self.get_binary());
+        cmd.args(self.get_switches_install());
+
+        if noconfirm {
+            cmd.args(self.get_switches_noconfirm());
+        }
+
+        for p in packages {
+            cmd.arg(&p.name);
+            if let Some(repo) = p.repo.as_ref() {
+                cmd.args(["--repo", repo]);
+            }
+        }
+
+        // add these two repositories as these are needed for many dependencies
+        cmd.args(["--repo", "updates"]);
+        cmd.args(["--repo", "fedora"]);
+
+        run_external_command(cmd)
+    }
+
+    /// Show information from package manager for package.
+    fn remove_packages(&self, packages: &[Package], noconfirm: bool) -> Result<()> {
+        let mut cmd = Command::new("sudo");
+        cmd.arg(self.get_binary());
+        cmd.args(self.get_switches_remove());
+
+        if noconfirm {
+            cmd.args(self.get_switches_noconfirm());
+        }
+
+        for p in packages {
+            cmd.arg(&p.name);
+        }
+
+        run_external_command(cmd)
+    }
+
+    fn show_package_info(&self, package: &Package) -> Result<()> {
+        let mut cmd = Command::new(self.get_binary());
+        cmd.args(self.get_switches_info());
+        cmd.arg(&package.name);
+
+        run_external_command(cmd)
+    }
+
+    fn make_dependency(&self, _: &[Package]) -> Result<()> {
+        panic!("Not supported by the package manager!")
+    }
+}
+
+impl Fedora {
+    pub fn new() -> Self {
+        Self {
+            packages: HashSet::new(),
+        }
+    }
+}
+
+fn create_package(package: &str) -> Package {
+    if DEFAULT_REPOS.iter().any(|repo| package.contains(repo)) && !package.contains("copr") {
+        let package = package.split('/').nth(1).expect("Cannot be empty!");
+        package.into()
+    } else {
+        package.into()
+    }
+}

crates/pacdef_core/src/backend/actual/mod.rs

@@ -2,6 +2,7 @@
 pub mod arch;
 #[cfg(feature = "debian")]
 pub mod debian;
+pub mod fedora;
 pub mod flatpak;
 pub mod python;
 pub mod rust;

crates/pacdef_core/src/backend/mod.rs

@@ -18,6 +18,7 @@ pub enum Backends {
     #[cfg(feature = "debian")]
     Debian,
     Flatpak,
+    Fedora,
     Python,
     Rust,
     Rustup,