Refactor config parsing files

This is a large refactor of the config parsing structure, attempting to
reduce the size of the file a bit by splitting it up into different
modules with more specific purposes.

This also fixes #2279.

1 files changed, 263 insertions, 154 deletions

diff --git a/alacritty/src/cli.rs b/alacritty/src/cli.rs
index 90906218..3ecea644 100644
--- a/alacritty/src/cli.rs
+++ b/alacritty/src/cli.rs
@@ -12,184 +12,293 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-use std::path::PathBuf;
+use std::borrow::Cow;
+use std::cmp::max;
+use std::path::{Path, PathBuf};
 
-use ::log;
 use clap::{crate_authors, crate_description, crate_name, crate_version, App, Arg};
+use log::{self, LevelFilter};
 
-use alacritty_terminal::config::{Options, Delta, Dimensions, Shell};
+use alacritty_terminal::config::{Config, Delta, Dimensions, Shell};
 use alacritty_terminal::index::{Column, Line};
 use alacritty_terminal::window::DEFAULT_NAME;
 
-/// Build `Options` from command line arguments.
-pub fn options() -> Options {
-    let mut options = Options::default();
-
-    let version_string = format!("{} ({})",
-                                 crate_version!(),
-                                 env!("GIT_HASH"));
-
-    let matches = App::new(crate_name!())
-        .version(version_string.as_str())
-        .author(crate_authors!("\n"))
-        .about(crate_description!())
-        .arg(Arg::with_name("ref-test").long("ref-test").help("Generates ref test"))
-        .arg(
-            Arg::with_name("live-config-reload")
-                .long("live-config-reload")
-                .help("Enable automatic config reloading"),
-        )
-        .arg(
-            Arg::with_name("no-live-config-reload")
-                .long("no-live-config-reload")
-                .help("Disable automatic config reloading")
-                .conflicts_with("live-config-reload"),
-        )
-        .arg(
-            Arg::with_name("print-events")
-                .long("print-events")
-                .help("Print all events to stdout"),
-        )
-        .arg(
-            Arg::with_name("persistent-logging")
-                .long("persistent-logging")
-                .help("Keep the log file after quitting Alacritty"),
-        )
-        .arg(
-            Arg::with_name("dimensions")
-                .long("dimensions")
-                .short("d")
-                .value_names(&["columns", "lines"])
-                .help(
-                    "Defines the window dimensions. Falls back to size specified by window \
-                     manager if set to 0x0 [default: 0x0]",
-                ),
-        )
-        .arg(
-            Arg::with_name("position")
-                .long("position")
-                .allow_hyphen_values(true)
-                .value_names(&["x-pos", "y-pos"])
-                .help(
-                    "Defines the window position. Falls back to position specified by window \
-                     manager if unset [default: unset]",
-                ),
-        )
-        .arg(
-            Arg::with_name("title")
-                .long("title")
-                .short("t")
-                .takes_value(true)
-                .help(&format!("Defines the window title [default: {}]", DEFAULT_NAME)),
-        )
-        .arg(
-            Arg::with_name("class")
-                .long("class")
-                .takes_value(true)
-                .help(&format!("Defines window class on Linux [default: {}]", DEFAULT_NAME)),
-        )
-        .arg(
-            Arg::with_name("q")
-                .short("q")
-                .multiple(true)
-                .conflicts_with("v")
-                .help("Reduces the level of verbosity (the min level is -qq)"),
-        )
-        .arg(
-            Arg::with_name("v")
-                .short("v")
-                .multiple(true)
-                .conflicts_with("q")
-                .help("Increases the level of verbosity (the max level is -vvv)"),
-        )
-        .arg(
-            Arg::with_name("working-directory")
-                .long("working-directory")
-                .takes_value(true)
-                .help("Start the shell in the specified working directory"),
-        )
-        .arg(Arg::with_name("config-file").long("config-file").takes_value(true).help(
-            "Specify alternative configuration file [default: \
-             $XDG_CONFIG_HOME/alacritty/alacritty.yml]",
-        ))
-        .arg(
-            Arg::with_name("command")
-                .long("command")
-                .short("e")
-                .multiple(true)
-                .takes_value(true)
-                .min_values(1)
-                .allow_hyphen_values(true)
-                .help("Command and args to execute (must be last argument)"),
-        )
-        .get_matches();
-
-    if matches.is_present("ref-test") {
-        options.ref_test = true;
-    }
+/// Options specified on the command line
+pub struct Options {
+    pub live_config_reload: Option<bool>,
+    pub print_events: bool,
+    pub ref_test: bool,
+    pub dimensions: Option<Dimensions>,
+    pub position: Option<Delta<i32>>,
+    pub title: Option<String>,
+    pub class: Option<String>,
+    pub log_level: LevelFilter,
+    pub command: Option<Shell<'static>>,
+    pub working_dir: Option<PathBuf>,
+    pub config: Option<PathBuf>,
+    pub persistent_logging: bool,
+}
 
-    if matches.is_present("print-events") {
-        options.print_events = true;
+impl Default for Options {
+    fn default() -> Options {
+        Options {
+            live_config_reload: None,
+            print_events: false,
+            ref_test: false,
+            dimensions: None,
+            position: None,
+            title: None,
+            class: None,
+            log_level: LevelFilter::Warn,
+            command: None,
+            working_dir: None,
+            config: None,
+            persistent_logging: false,
+        }
     }
+}
 
-    if matches.is_present("live-config-reload") {
-        options.live_config_reload = Some(true);
-    } else if matches.is_present("no-live-config-reload") {
-        options.live_config_reload = Some(false);
-    }
+impl Options {
+    /// Build `Options` from command line arguments.
+    pub fn new() -> Self {
+        let mut options = Options::default();
 
-    if matches.is_present("persistent-logging") {
-        options.persistent_logging = true;
-    }
+        let version_string = format!("{} ({})", crate_version!(), env!("GIT_HASH"));
 
-    if let Some(mut dimensions) = matches.values_of("dimensions") {
-        let width = dimensions.next().map(|w| w.parse().map(Column));
-        let height = dimensions.next().map(|h| h.parse().map(Line));
-        if let (Some(Ok(width)), Some(Ok(height))) = (width, height) {
-            options.dimensions = Some(Dimensions::new(width, height));
+        let matches = App::new(crate_name!())
+            .version(version_string.as_str())
+            .author(crate_authors!("\n"))
+            .about(crate_description!())
+            .arg(Arg::with_name("ref-test").long("ref-test").help("Generates ref test"))
+            .arg(
+                Arg::with_name("live-config-reload")
+                    .long("live-config-reload")
+                    .help("Enable automatic config reloading"),
+            )
+            .arg(
+                Arg::with_name("no-live-config-reload")
+                    .long("no-live-config-reload")
+                    .help("Disable automatic config reloading")
+                    .conflicts_with("live-config-reload"),
+            )
+            .arg(
+                Arg::with_name("print-events")
+                    .long("print-events")
+                    .help("Print all events to stdout"),
+            )
+            .arg(
+                Arg::with_name("persistent-logging")
+                    .long("persistent-logging")
+                    .help("Keep the log file after quitting Alacritty"),
+            )
+            .arg(
+                Arg::with_name("dimensions")
+                    .long("dimensions")
+                    .short("d")
+                    .value_names(&["columns", "lines"])
+                    .help(
+                        "Defines the window dimensions. Falls back to size specified by window \
+                         manager if set to 0x0 [default: 0x0]",
+                    ),
+            )
+            .arg(
+                Arg::with_name("position")
+                    .long("position")
+                    .allow_hyphen_values(true)
+                    .value_names(&["x-pos", "y-pos"])
+                    .help(
+                        "Defines the window position. Falls back to position specified by window \
+                         manager if unset [default: unset]",
+                    ),
+            )
+            .arg(
+                Arg::with_name("title")
+                    .long("title")
+                    .short("t")
+                    .takes_value(true)
+                    .help(&format!("Defines the window title [default: {}]", DEFAULT_NAME)),
+            )
+            .arg(
+                Arg::with_name("class")
+                    .long("class")
+                    .takes_value(true)
+                    .help(&format!("Defines window class on Linux [default: {}]", DEFAULT_NAME)),
+            )
+            .arg(
+                Arg::with_name("q")
+                    .short("q")
+                    .multiple(true)
+                    .conflicts_with("v")
+                    .help("Reduces the level of verbosity (the min level is -qq)"),
+            )
+            .arg(
+                Arg::with_name("v")
+                    .short("v")
+                    .multiple(true)
+                    .conflicts_with("q")
+                    .help("Increases the level of verbosity (the max level is -vvv)"),
+            )
+            .arg(
+                Arg::with_name("working-directory")
+                    .long("working-directory")
+                    .takes_value(true)
+                    .help("Start the shell in the specified working directory"),
+            )
+            .arg(Arg::with_name("config-file").long("config-file").takes_value(true).help(
+                "Specify alternative configuration file [default: \
+                 $XDG_CONFIG_HOME/alacritty/alacritty.yml]",
+            ))
+            .arg(
+                Arg::with_name("command")
+                    .long("command")
+                    .short("e")
+                    .multiple(true)
+                    .takes_value(true)
+                    .min_values(1)
+                    .allow_hyphen_values(true)
+                    .help("Command and args to execute (must be last argument)"),
+            )
+            .get_matches();
+
+        if matches.is_present("ref-test") {
+            options.ref_test = true;
         }
-    }
 
-    if let Some(mut position) = matches.values_of("position") {
-        let x = position.next().map(str::parse);
-        let y = position.next().map(str::parse);
-        if let (Some(Ok(x)), Some(Ok(y))) = (x, y) {
-            options.position = Some(Delta { x, y });
+        if matches.is_present("print-events") {
+            options.print_events = true;
+        }
+
+        if matches.is_present("live-config-reload") {
+            options.live_config_reload = Some(true);
+        } else if matches.is_present("no-live-config-reload") {
+            options.live_config_reload = Some(false);
         }
-    }
 
-    options.class = matches.value_of("class").map(ToOwned::to_owned);
-    options.title = matches.value_of("title").map(ToOwned::to_owned);
+        if matches.is_present("persistent-logging") {
+            options.persistent_logging = true;
+        }
+
+        if let Some(mut dimensions) = matches.values_of("dimensions") {
+            let width = dimensions.next().map(|w| w.parse().map(Column));
+            let height = dimensions.next().map(|h| h.parse().map(Line));
+            if let (Some(Ok(width)), Some(Ok(height))) = (width, height) {
+                options.dimensions = Some(Dimensions::new(width, height));
+            }
+        }
+
+        if let Some(mut position) = matches.values_of("position") {
+            let x = position.next().map(str::parse);
+            let y = position.next().map(str::parse);
+            if let (Some(Ok(x)), Some(Ok(y))) = (x, y) {
+                options.position = Some(Delta { x, y });
+            }
+        }
+
+        options.class = matches.value_of("class").map(ToOwned::to_owned);
+        options.title = matches.value_of("title").map(ToOwned::to_owned);
 
-    match matches.occurrences_of("q") {
-        0 => {},
-        1 => options.log_level = log::LevelFilter::Error,
-        2 | _ => options.log_level = log::LevelFilter::Off,
+        match matches.occurrences_of("q") {
+            0 => {},
+            1 => options.log_level = LevelFilter::Error,
+            2 | _ => options.log_level = LevelFilter::Off,
+        }
+
+        match matches.occurrences_of("v") {
+            0 if !options.print_events => options.log_level = LevelFilter::Warn,
+            0 | 1 => options.log_level = LevelFilter::Info,
+            2 => options.log_level = LevelFilter::Debug,
+            3 | _ => options.log_level = LevelFilter::Trace,
+        }
+
+        if let Some(dir) = matches.value_of("working-directory") {
+            options.working_dir = Some(PathBuf::from(dir.to_string()));
+        }
+
+        if let Some(path) = matches.value_of("config-file") {
+            options.config = Some(PathBuf::from(path.to_string()));
+        }
+
+        if let Some(mut args) = matches.values_of("command") {
+            // The following unwrap is guaranteed to succeed.
+            // If 'command' exists it must also have a first item since
+            // Arg::min_values(1) is set.
+            let command = String::from(args.next().unwrap());
+            let args = args.map(String::from).collect();
+            options.command = Some(Shell::new_with_args(command, args));
+        }
+
+        options
     }
 
-    match matches.occurrences_of("v") {
-        0 if !options.print_events => {},
-        0 | 1 => options.log_level = log::LevelFilter::Info,
-        2 => options.log_level = log::LevelFilter::Debug,
-        3 | _ => options.log_level = log::LevelFilter::Trace,
+    pub fn config_path(&self) -> Option<Cow<'_, Path>> {
+        self.config.as_ref().map(|p| Cow::Borrowed(p.as_path()))
     }
 
-    if let Some(dir) = matches.value_of("working-directory") {
-        options.working_dir = Some(PathBuf::from(dir.to_string()));
+    pub fn into_config(self, mut config: Config) -> Config {
+        config.set_live_config_reload(
+            self.live_config_reload.unwrap_or_else(|| config.live_config_reload()),
+        );
+        config.set_working_directory(
+            self.working_dir.or_else(|| config.working_directory().to_owned()),
+        );
+        config.shell = self.command.or(config.shell);
+
+        config.window.dimensions = self.dimensions.unwrap_or(config.window.dimensions);
+        config.window.position = self.position.or(config.window.position);
+        config.window.title = self.title.or(config.window.title);
+        config.window.class = self.class.or(config.window.class);
+
+        config.set_dynamic_title(config.dynamic_title() && config.window.title.is_none());
+
+        config.debug.print_events = self.print_events || config.debug.print_events;
+        config.debug.log_level = max(config.debug.log_level, self.log_level);
+        config.debug.ref_test = self.ref_test || config.debug.ref_test;
+
+        if config.debug.print_events {
+            config.debug.log_level = max(config.debug.log_level, LevelFilter::Info);
+        }
+
+        config
     }
+}
+
+#[cfg(test)]
+mod test {
+    use alacritty_terminal::config::{Config, DEFAULT_ALACRITTY_CONFIG};
+
+    use crate::cli::Options;
+
+    #[test]
+    fn dynamic_title_ignoring_options_by_default() {
+        let config: Config =
+            ::serde_yaml::from_str(DEFAULT_ALACRITTY_CONFIG).expect("deserialize config");
+        let old_dynamic_title = config.dynamic_title();
+
+        let config = Options::default().into_config(config);
 
-    if let Some(path) = matches.value_of("config-file") {
-        options.config = Some(PathBuf::from(path.to_string()));
+        assert_eq!(old_dynamic_title, config.dynamic_title());
     }
 
-    if let Some(mut args) = matches.values_of("command") {
-        // The following unwrap is guaranteed to succeed.
-        // If 'command' exists it must also have a first item since
-        // Arg::min_values(1) is set.
-        let command = String::from(args.next().unwrap());
-        let args = args.map(String::from).collect();
-        options.command = Some(Shell::new_with_args(command, args));
+    #[test]
+    fn dynamic_title_overridden_by_options() {
+        let config: Config =
+            ::serde_yaml::from_str(DEFAULT_ALACRITTY_CONFIG).expect("deserialize config");
+
+        let mut options = Options::default();
+        options.title = Some("foo".to_owned());
+        let config = options.into_config(config);
+
+        assert!(!config.dynamic_title());
     }
 
-    options
+    #[test]
+    fn dynamic_title_overridden_by_config() {
+        let mut config: Config =
+            ::serde_yaml::from_str(DEFAULT_ALACRITTY_CONFIG).expect("deserialize config");
+
+        config.window.title = Some("foo".to_owned());
+        let config = Options::default().into_config(config);
+
+        assert!(!config.dynamic_title());
+    }
 }