add a dry-run mode to install

1 files changed, 20 insertions, 3 deletions

diff --git a/src/main.rs b/src/main.rs
index 5df16a2..bff0fe0 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -44,6 +44,12 @@ fn main() -> Result<()> {
                         .short("t")
                         .long("target-dir")
                         .default_value("."),
+                )
+                .arg(
+                    Arg::with_name("dry-run")
+                        .short("n")
+                        .long("dry-run")
+                        .required(false),
                 ),
         )
         .get_matches();
@@ -68,8 +74,7 @@ fn main() -> Result<()> {
 
     if let Some(install) = matches.subcommand_matches("install") {
         let mods = install.values_of("mod").unwrap().collect::<Vec<_>>();
-        let target_dir = install.value_of("target").unwrap();
-        install_mods(&mut stdout, &snapshot, &world, &mods, Path::new(target_dir))?;
+        install_mods(&mut stdout, &snapshot, &world, &mods, install)?;
     }
 
     Ok(())
@@ -183,8 +188,11 @@ fn install_mods(
     snapshot: &Snapshot,
     world: &World,
     mods: &[&str],
-    target_dir: &Path,
+    matches: &ArgMatches,
 ) -> Result<()> {
+    let target_dir = &Path::new(matches.value_of("target").unwrap());
+    let dry_run = matches.is_present("dry-run");
+
     let content_db = ContentDb::new();
     let downloader = Downloader::new()?;
     let mut wanted = mods
@@ -266,6 +274,15 @@ fn install_mods(
 
     ask_continue(output)?;
 
+    if dry_run {
+        for m in to_install {
+            let mod_id = m.mod_id()?;
+            let mod_dir = target_dir.join(&mod_id);
+            writeln!(output, "Installing {} to {:?}", mod_id, mod_dir)?;
+        }
+        return Ok(());
+    }
+
     for m in to_install {
         let mod_id = m.mod_id()?;
         writeln!(output, "Installing {}", mod_id)?;