Split options parsing into several functions

Author: popzxc

src/libtest/cli.rs

@@ -40,7 +40,7 @@ impl TestOpts {
 /// Result of parsing the options.
 pub type OptRes = Result<TestOpts, String>;
 /// Result of parsing the option part.
-type OptPartRes<T> = Result<Option<T>, String>;
+type OptPartRes<T> = Result<T, String>;
 
 fn optgroups() -> getopts::Options {
     let mut opts = getopts::Options::new();
@@ -186,36 +186,111 @@ Test Attributes:
     );
 }
 
-// FIXME: Copied from libsyntax until linkage errors are resolved. Issue #47566
-fn is_nightly() -> bool {
-    // Whether this is a feature-staged build, i.e., on the beta or stable channel
-    let disable_unstable_features = option_env!("CFG_DISABLE_UNSTABLE_FEATURES").is_some();
-    // Whether we should enable unstable features for bootstrapping
-    let bootstrap = env::var("RUSTC_BOOTSTRAP").is_ok();
+/// Parses command line arguments into test options.
+/// Returns `None` if help was requested (since we only show help message and don't run tests),
+/// returns `Some(Err(..))` if provided arguments are incorrect,
+/// otherwise creates a `TestOpts` object and returns it.
+pub fn parse_opts(args: &[String]) -> Option<OptRes> {
+    // Parse matches.
+    let opts = optgroups();
+    let args = args.get(1..).unwrap_or(args);
+    let matches = match opts.parse(args) {
+        Ok(m) => m,
+        Err(f) => return Some(Err(f.to_string())),
+    };
 
-    bootstrap || !disable_unstable_features
+    // Check if help was requested.
+    if matches.opt_present("h") {
+        // Show help and do nothing more.
+        usage(&args[0], &opts);
+        return None;
+    }
+
+    // Actually parse the opts.
+    let opts_result = parse_opts_impl(matches);
+
+    Some(opts_result)
 }
 
 // Gets the option value and checks if unstable features are enabled.
 macro_rules! unstable_optflag {
     ($matches:ident, $allow_unstable:ident, $option_name:literal) => {{
         let opt = $matches.opt_present($option_name);
         if !$allow_unstable && opt {
-            return Some(Err(format!(
+            return Err(format!(
                 "The \"{}\" flag is only accepted on the nightly compiler",
                 $option_name
-            )));
+            ));
         }
 
         opt
     }};
 }
 
+// Implementation of `parse_opts` that doesn't care about help message
+// and returns a `Result`.
+fn parse_opts_impl(matches: getopts::Matches) -> OptRes {
+    let allow_unstable = get_allow_unstable(&matches)?;
+
+    // Unstable flags
+    let exclude_should_panic = unstable_optflag!(matches, allow_unstable, "exclude-should-panic");
+    let include_ignored = unstable_optflag!(matches, allow_unstable, "include-ignored");
+    let time_options = get_time_options(&matches, allow_unstable)?;
+
+    let quiet = matches.opt_present("quiet");
+    let exact = matches.opt_present("exact");
+    let list = matches.opt_present("list");
+    let skip = matches.opt_strs("skip");
+
+    let bench_benchmarks = matches.opt_present("bench");
+    let run_tests = !bench_benchmarks || matches.opt_present("test");
+
+    let logfile = get_log_file(&matches)?;
+    let run_ignored = get_run_ignored(&matches, include_ignored)?;
+    let filter = get_filter(&matches)?;
+    let nocapture = get_nocapture(&matches)?;
+    let test_threads = get_test_threads(&matches)?;
+    let color = get_color_config(&matches)?;
+    let format = get_format(&matches, quiet, allow_unstable)?;
+
+    let options = Options::new().display_output(matches.opt_present("show-output"));
+
+    let test_opts = TestOpts {
+        list,
+        filter,
+        filter_exact: exact,
+        exclude_should_panic,
+        run_ignored,
+        run_tests,
+        bench_benchmarks,
+        logfile,
+        nocapture,
+        color,
+        format,
+        test_threads,
+        skip,
+        time_options,
+        options,
+    };
+
+    Ok(test_opts)
+}
+
+// FIXME: Copied from libsyntax until linkage errors are resolved. Issue #47566
+fn is_nightly() -> bool {
+    // Whether this is a feature-staged build, i.e., on the beta or stable channel
+    let disable_unstable_features = option_env!("CFG_DISABLE_UNSTABLE_FEATURES").is_some();
+    // Whether we should enable unstable features for bootstrapping
+    let bootstrap = env::var("RUSTC_BOOTSTRAP").is_ok();
+
+    bootstrap || !disable_unstable_features
+}
+
 // Gets the CLI options assotiated with `report-time` feature.
 fn get_time_options(
     matches: &getopts::Matches,
     allow_unstable: bool)
--> Option<OptPartRes<TestTimeOptions>> {
+-> OptPartRes<Option<TestTimeOptions>> {
     let report_time = unstable_optflag!(matches, allow_unstable, "report-time");
     let colored_opt_str = matches.opt_str("report-time");
     let mut report_time_colored = report_time && colored_opt_str == Some("colored".into());
@@ -232,71 +307,73 @@ fn get_time_options(
         None
     };
 
-    Some(Ok(options))
+    Ok(options)
 }
 
-// Parses command line arguments into test options
-pub fn parse_opts(args: &[String]) -> Option<OptRes> {
-    let mut allow_unstable = false;
-    let opts = optgroups();
-    let args = args.get(1..).unwrap_or(args);
-    let matches = match opts.parse(args) {
-        Ok(m) => m,
-        Err(f) => return Some(Err(f.to_string())),
+fn get_test_threads(matches: &getopts::Matches) -> OptPartRes<Option<usize>> {
+    let test_threads = match matches.opt_str("test-threads") {
+        Some(n_str) => match n_str.parse::<usize>() {
+            Ok(0) => return Err("argument for --test-threads must not be 0".to_string()),
+            Ok(n) => Some(n),
+            Err(e) => {
+                return Err(format!(
+                    "argument for --test-threads must be a number > 0 \
+                     (error: {})",
+                    e
+                ));
+            }
+        },
+        None => None,
     };
 
-    if let Some(opt) = matches.opt_str("Z") {
-        if !is_nightly() {
-            return Some(Err(
-                "the option `Z` is only accepted on the nightly compiler".into(),
-            ));
-        }
+    Ok(test_threads)
+}
 
-        match &*opt {
-            "unstable-options" => {
-                allow_unstable = true;
-            }
-            _ => {
-                return Some(Err("Unrecognized option to `Z`".into()));
+fn get_format(matches: &getopts::Matches, quiet: bool, allow_unstable: bool) -> OptPartRes<OutputFormat> {
+    let format = match matches.opt_str("format").as_ref().map(|s| &**s) {
+        None if quiet => OutputFormat::Terse,
+        Some("pretty") | None => OutputFormat::Pretty,
+        Some("terse") => OutputFormat::Terse,
+        Some("json") => {
+            if !allow_unstable {
+                return Err(
+                    "The \"json\" format is only accepted on the nightly compiler".into(),
+                );
             }
+            OutputFormat::Json
         }
-    };
 
-    if matches.opt_present("h") {
-        usage(&args[0], &opts);
-        return None;
-    }
-
-    let filter = if !matches.free.is_empty() {
-        Some(matches.free[0].clone())
-    } else {
-        None
+        Some(v) => {
+            return Err(format!(
+                "argument for --format must be pretty, terse, or json (was \
+                 {})",
+                v
+            ));
+        }
     };
 
-    let exclude_should_panic = unstable_optflag!(matches, allow_unstable, "exclude-should-panic");
+    Ok(format)
+}
 
-    let include_ignored = unstable_optflag!(matches, allow_unstable, "include-ignored");
+fn get_color_config(matches: &getopts::Matches) -> OptPartRes<ColorConfig> {
+    let color = match matches.opt_str("color").as_ref().map(|s| &**s) {
+        Some("auto") | None => ColorConfig::AutoColor,
+        Some("always") => ColorConfig::AlwaysColor,
+        Some("never") => ColorConfig::NeverColor,
 
-    let run_ignored = match (include_ignored, matches.opt_present("ignored")) {
-        (true, true) => {
-            return Some(Err(
-                "the options --include-ignored and --ignored are mutually exclusive".into(),
+        Some(v) => {
+            return Err(format!(
+                "argument for --color must be auto, always, or never (was \
+                 {})",
+                v
             ));
         }
-        (true, false) => RunIgnored::Yes,
-        (false, true) => RunIgnored::Only,
-        (false, false) => RunIgnored::No,
     };
-    let quiet = matches.opt_present("quiet");
-    let exact = matches.opt_present("exact");
-    let list = matches.opt_present("list");
 
-    let logfile = matches.opt_str("logfile");
-    let logfile = logfile.map(|s| PathBuf::from(&s));
-
-    let bench_benchmarks = matches.opt_present("bench");
-    let run_tests = !bench_benchmarks || matches.opt_present("test");
+    Ok(color)
+}
 
+fn get_nocapture(matches: &getopts::Matches) -> OptPartRes<bool> {
     let mut nocapture = matches.opt_present("nocapture");
     if !nocapture {
         nocapture = match env::var("RUST_TEST_NOCAPTURE") {
@@ -305,80 +382,59 @@ pub fn parse_opts(args: &[String]) -> Option<OptRes> {
         };
     }
 
-    let time_options = match get_time_options(&matches, allow_unstable) {
-        Some(Ok(val)) => val,
-        Some(Err(e)) => return Some(Err(e)),
-        None => panic!("Unexpected output from `get_time_options`"),
-    };
+    Ok(nocapture)
+}
 
-    let test_threads = match matches.opt_str("test-threads") {
-        Some(n_str) => match n_str.parse::<usize>() {
-            Ok(0) => return Some(Err("argument for --test-threads must not be 0".to_string())),
-            Ok(n) => Some(n),
-            Err(e) => {
-                return Some(Err(format!(
-                    "argument for --test-threads must be a number > 0 \
-                     (error: {})",
-                    e
-                )));
-            }
-        },
-        None => None,
+fn get_run_ignored(matches: &getopts::Matches, include_ignored: bool) -> OptPartRes<RunIgnored> {
+    let run_ignored = match (include_ignored, matches.opt_present("ignored")) {
+        (true, true) => {
+            return Err(
+                "the options --include-ignored and --ignored are mutually exclusive".into(),
+            );
+        }
+        (true, false) => RunIgnored::Yes,
+        (false, true) => RunIgnored::Only,
+        (false, false) => RunIgnored::No,
     };
 
-    let color = match matches.opt_str("color").as_ref().map(|s| &**s) {
-        Some("auto") | None => ColorConfig::AutoColor,
-        Some("always") => ColorConfig::AlwaysColor,
-        Some("never") => ColorConfig::NeverColor,
+    Ok(run_ignored)
+}
 
-        Some(v) => {
-            return Some(Err(format!(
-                "argument for --color must be auto, always, or never (was \
-                 {})",
-                v
-            )));
-        }
+fn get_filter(matches: &getopts::Matches) -> OptPartRes<Option<String>> {
+    let filter = if !matches.free.is_empty() {
+        Some(matches.free[0].clone())
+    } else {
+        None
     };
 
-    let format = match matches.opt_str("format").as_ref().map(|s| &**s) {
-        None if quiet => OutputFormat::Terse,
-        Some("pretty") | None => OutputFormat::Pretty,
-        Some("terse") => OutputFormat::Terse,
-        Some("json") => {
-            if !allow_unstable {
-                return Some(Err(
-                    "The \"json\" format is only accepted on the nightly compiler".into(),
-                ));
-            }
-            OutputFormat::Json
+    Ok(filter)
+}
+
+fn get_allow_unstable(matches: &getopts::Matches) -> OptPartRes<bool> {
+    let mut allow_unstable = false;
+
+    if let Some(opt) = matches.opt_str("Z") {
+        if !is_nightly() {
+            return Err(
+                "the option `Z` is only accepted on the nightly compiler".into(),
+            );
         }
 
-        Some(v) => {
-            return Some(Err(format!(
-                "argument for --format must be pretty, terse, or json (was \
-                 {})",
-                v
-            )));
+        match &*opt {
+            "unstable-options" => {
+                allow_unstable = true;
+            }
+            _ => {
+                return Err("Unrecognized option to `Z`".into());
+            }
         }
     };
 
-    let test_opts = TestOpts {
-        list,
-        filter,
-        filter_exact: exact,
-        exclude_should_panic,
-        run_ignored,
-        run_tests,
-        bench_benchmarks,
-        logfile,
-        nocapture,
-        color,
-        format,
-        test_threads,
-        skip: matches.opt_strs("skip"),
-        time_options,
-        options: Options::new().display_output(matches.opt_present("show-output")),
-    };
+    Ok(allow_unstable)
+}
+
+fn get_log_file(matches: &getopts::Matches) -> OptPartRes<Option<PathBuf>> {
+    let logfile = matches.opt_str("logfile").map(|s| PathBuf::from(&s));
 
-    Some(Ok(test_opts))
+    Ok(logfile)
 }