Filtering of component list by available, required, and installed

src/rustup-cli/common.rs

@@ -320,9 +320,25 @@ pub fn list_targets(toolchain: &Toolchain) -> Result<()> {
     Ok(())
 }
 
-pub fn list_components(toolchain: &Toolchain) -> Result<()> {
+pub enum ComponentFilter {
+    Required,
+    Available,
+    Installed,
+    None,
+}
+
+pub fn list_components(toolchain: &Toolchain, filter: &ComponentFilter) -> Result<()> {
     let mut t = term2::stdout();
-    for component in toolchain.list_components()? {
+    let components = toolchain
+        .list_components()?
+        .into_iter()
+        .filter(|c| match filter {
+            ComponentFilter::Required => c.required,
+            ComponentFilter::Available => c.available && !c.installed,
+            ComponentFilter::Installed => c.installed,
+            ComponentFilter::None => c.required || c.available || c.installed,
+        });
+    for component in components {
         let name = component.name;
         if component.required {
             let _ = t.attr(term2::Attr::Bold);

src/rustup-cli/help.rs

@@ -254,3 +254,6 @@ r"DISCUSSION:
 pub static TOOLCHAIN_ARG_HELP: &'static str = "Toolchain name, such as 'stable', 'nightly', \
                                                or '1.8.0'. For more information see `rustup \
                                                help toolchain`";
+
+pub static FILTER_ARG_HELP: &'static str =
+    "Component status: 'required', 'available', or 'installed'";

src/rustup-cli/rustup_mode.rs

@@ -296,6 +296,12 @@ pub fn cli() -> App<'static, 'static> {
                                 .help(TOOLCHAIN_ARG_HELP)
                                 .long("toolchain")
                                 .takes_value(true),
+                        )
+                        .arg(
+                            Arg::with_name("filter")
+                                .help(FILTER_ARG_HELP)
+                                .long("filter")
+                                .takes_value(true),
                         ),
                 )
                 .subcommand(
@@ -825,7 +831,13 @@ fn target_remove(cfg: &Cfg, m: &ArgMatches) -> Result<()> {
 fn component_list(cfg: &Cfg, m: &ArgMatches) -> Result<()> {
     let toolchain = explicit_or_dir_toolchain(cfg, m)?;
 
-    common::list_components(&toolchain)
+    let filter = match m.value_of("filter") {
+        Some("required") => common::ComponentFilter::Required,
+        Some("available") => common::ComponentFilter::Available,
+        Some("installed") => common::ComponentFilter::Installed,
+        _ => common::ComponentFilter::None,
+    };
+    common::list_components(&toolchain, &filter)
 }
 
 fn component_add(cfg: &Cfg, m: &ArgMatches) -> Result<()> {

tests/cli-rustup.rs

@@ -1093,6 +1093,80 @@ fn add_remove_multiple_components() {
     });
 }
 
+#[test]
+fn list_components_filter() {
+    setup(&|config| {
+        expect_err(
+            config,
+            &["rustup", "component", "list", "--filter", "required"],
+            "error: no default toolchain configured",
+        );
+        expect_ok(config, &["rustup", "default", "nightly"]);
+        expect_ok_ex(
+            config,
+            &["rustup", "component", "list", "--filter", "required"],
+            for_host!(
+                r"cargo-{0} (default)
+rust-docs-{0} (default)
+rust-std-{0} (default)
+rustc-{0} (default)
+"
+            ),
+            "",
+        );
+        expect_ok(
+            config,
+            &["rustup", "component", "list", "--filter", "available"],
+        );
+        expect_ok_ex(
+            config,
+            &["rustup", "component", "list", "--filter", "installed"],
+            for_host!(
+                "cargo-{0} (default)
+rust-docs-{0} (default)
+rust-std-{0} (default)
+rustc-{0} (default)
+"
+            ),
+            "",
+        );
+        expect_ok(config, &["rustup", "component", "add", "rls"]);
+        expect_ok_ex(
+            config,
+            &["rustup", "component", "list", "--filter", "installed"],
+            for_host!(
+                "cargo-{0} (default)
+rls-{0} (installed)
+rust-docs-{0} (default)
+rust-std-{0} (default)
+rustc-{0} (default)
+"
+            ),
+            "",
+        );
+        expect_err(
+            config,
+            &["rustup", "component", "list", "--filter"],
+            "error: The argument '--filter <filter>' requires a value but none was supplied",
+        );
+
+        // Don't show installed/default components in available filter
+        let mut cmd = clitools::cmd(
+            config,
+            "rustup",
+            &["component", "list", "--filter", "available"],
+        );
+        clitools::env(config, &mut cmd);
+        let out = cmd.output().unwrap();
+        assert!(!String::from_utf8(out.stdout.clone())
+            .unwrap()
+            .contains("(installed)"));
+        assert!(!String::from_utf8(out.stdout.clone())
+            .unwrap()
+            .contains("(default)"));
+    });
+}
+
 // Run without setting RUSTUP_HOME, with setting HOME and USERPROFILE
 fn run_no_home(config: &Config, args: &[&str], env: &[(&str, &str)]) -> process::Output {
     let home_dir_str = &format!("{}", config.homedir.display());