Adding a new flag for cleaning up old resources (#90)

* Adding a new flag to topgrade called "cleanup"

If you are using applications like homebrew they may keep a history of
packages downloaded. Especially the bigger your number of installed
packages for homebrew grows the bigger those directories get. This can
quickly add up to a couple of GBs.

If this flag is set then the homebrew part also calls "brew cleanup" for
cleaning up old resources. Of course this can be add to other calls as
well if supported.

* Updating readme for new cleanup flag

README.md

@@ -87,6 +87,7 @@ Just run `topgrade`. It will run the following steps:
 ## Flags
 * `-t/--tmux` - Topgrade will launch itself in a new tmux session. This flag has no effect if
   Topgrade already runs inside tmux. This is useful when using topgrade on remote systems.
+* `-c/--cleanup` - Topgrade will instruct package managers to remove old or unused files
 * `-n/--dry-run` - Print what should be run.
 * `--no-system` - Skip the system upgrade phase.
 * `--no-git-repos` - Don't pull custom git repositories.

src/config.rs

@@ -51,6 +51,9 @@ pub struct Opt {
     #[structopt(short = "t", long = "tmux", help = "Run inside tmux")]
     pub run_in_tmux: bool,
 
+    #[structopt(short = "c", long = "cleanup", help = "Cleanup temporary or old files")]
+    pub cleanup: bool,
+
     #[structopt(long = "no-system", help = "Don't perform system upgrade")]
     pub no_system: bool,
 

src/main.rs

@@ -240,7 +240,7 @@ fn run() -> Result<(), Error> {
 
     #[cfg(unix)]
     report.push_result(execute(
-        |terminal| unix::run_homebrew(terminal, opt.dry_run),
+        |terminal| unix::run_homebrew(terminal, opt.cleanup, opt.dry_run),
         &mut execution_context,
     )?);
     #[cfg(target_os = "freebsd")]

src/unix.rs

@@ -52,13 +52,16 @@ pub fn run_fisher(base_dirs: &BaseDirs, terminal: &mut Terminal, dry_run: bool)
 }
 
 #[must_use]
-pub fn run_homebrew(terminal: &mut Terminal, dry_run: bool) -> Option<(&'static str, bool)> {
+pub fn run_homebrew(terminal: &mut Terminal, cleanup: bool, dry_run: bool) -> Option<(&'static str, bool)> {
     if let Some(brew) = which("brew") {
         terminal.print_separator("Brew");
 
         let inner = || -> Result<(), Error> {
             Executor::new(&brew, dry_run).arg("update").spawn()?.wait()?.check()?;
             Executor::new(&brew, dry_run).arg("upgrade").spawn()?.wait()?.check()?;
+            if cleanup {
+                Executor::new(&brew, dry_run).arg("cleanup").spawn()?.wait()?.check()?;
+            }
             Ok(())
         };