change dump_completions to a subcommand

justfile

@@ -256,11 +256,11 @@ build-dist:
 dist-supplemental:
 	mkdir -p dist
 	@# Generate completions and store them in dist/
-	{{_cargo}} run --release {{_build_flags}} -- --dump-completions bash > dist/{{ _pkgname }}.bash
-	{{_cargo}} run --release {{_build_flags}} -- --dump-completions zsh > dist/{{ _pkgname }}.zsh
-	{{_cargo}} run --release {{_build_flags}} -- --dump-completions fish > dist/{{ _pkgname }}.fish
-	{{_cargo}} run --release {{_build_flags}} -- --dump-completions elvish > dist/{{ _pkgname }}.elvish
-	{{_cargo}} run --release {{_build_flags}} -- --dump-completions powershell > dist/{{ _pkgname }}.powershell
+	{{_cargo}} run --release {{_build_flags}} -- dump-completions bash > dist/{{ _pkgname }}.bash
+	{{_cargo}} run --release {{_build_flags}} -- dump-completions zsh > dist/{{ _pkgname }}.zsh
+	{{_cargo}} run --release {{_build_flags}} -- dump-completions fish > dist/{{ _pkgname }}.fish
+	{{_cargo}} run --release {{_build_flags}} -- dump-completions elvish > dist/{{ _pkgname }}.elvish
+	{{_cargo}} run --release {{_build_flags}} -- dump-completions powershell > dist/{{ _pkgname }}.powershell
 	@# Generate manpage and store it gzipped in dist/
 	@# (This comes last so the earlier calls to `cargo run` will get the compiler warnings out)
 	help2man -N '{{_cargo}} run {{_build_flags}} --' \

src/app.rs

@@ -76,6 +76,8 @@ pub enum Command {
     },
     /// List all available templates that can be downloaded
     ListTemplates,
+    /// Write a completion definition for the specified shell to stdout (bash, zsh, etc.)
+    DumpCompletions { shell: Option<structopt::clap::Shell> },
 }
 
 /// Runs the command `add`
@@ -134,12 +136,26 @@ fn run_list_templates() -> Result<()> {
     Ok(())
 }
 
+/// Runs the command `dump-completion` to generate a shell completion script
+fn run_dump_completion(shell: Option<structopt::clap::Shell>) -> Result<()> {
+    let shell = shell.ok_or(ErrorKind::NoShellProvided)?;
+    debug!("Request to dump completion for {}", shell);
+    CliOpts::clap().gen_completions_to(
+        CliOpts::clap().get_bin_name().unwrap_or_else(|| structopt::clap::crate_name!()),
+        shell,
+        &mut ::std::io::stdout(),
+    );
+
+    Ok(())
+}
+
 /// The actual `main()`
 pub fn main(opts: CliOpts) -> Result<()> {
     match opts.cmd {
         Command::Add { glob } => run_add(&glob)?,
         Command::Get { lang } => run_get(&lang)?,
         Command::ListTemplates => run_list_templates()?,
+        Command::DumpCompletions { shell } => run_dump_completion(shell)?,
     };
 
     Ok(())

src/cache.rs

@@ -1,6 +1,5 @@
 //! Module to implement a simple cache
 use crate::errors::*;
-use crate::template::GithubTemplates;
 use core::time::Duration;
 use log::{debug, trace};
 use serde::Serialize;
@@ -9,6 +8,10 @@ use std::io::{BufReader, BufWriter};
 use std::path::PathBuf;
 use std::time::SystemTime;
 
+/// Trait for a simple cache
+///
+/// Each struct implementing this trais has to offer functions to `get`, `set` an object and check
+/// if an value `exists`.
 pub trait Cache<T>
 where T: Serialize + serde::de::DeserializeOwned {
     /// Stores the `data` under the given `key`

src/errors.rs

@@ -21,6 +21,9 @@ error_chain! {
         TemplateNoContent {
             description("template contains no content that could be used or written. try to `load_content` first.")
         }
+        NoShellProvided {
+            description("no shell provided"),
+        }
     }
 
 }

src/helpers.rs

@@ -12,8 +12,8 @@ use crate::errors::*;
 use crate::{helpers, template::GithubTemplates};
 
 use directories::ProjectDirs;
-use std::path::PathBuf;
-use structopt::{clap, StructOpt};
+use std::{env, path::PathBuf};
+use structopt::StructOpt;
 
 /// Modified version of Clap's default template for proper help2man compatibility
 ///
@@ -47,10 +47,6 @@ pub struct BoilerplateOpts {
     /// Display timestamps on log messages (sec, ms, ns, none)
     #[structopt(short, long, value_name = "resolution")]
     pub timestamp: Option<stderrlog::Timestamp>,
-
-    /// Write a completion definition for the specified shell to stdout (bash, zsh, etc.)
-    #[structopt(long, value_name = "shell")]
-    pub dump_completions: Option<clap::Shell>,
 }
 
 /// Checks if the given dir contains the root `.git` dir

src/main.rs

@@ -35,12 +35,11 @@ extern crate error_chain;
 
 // stdlib imports
 use std::convert::TryInto;
-use std::io;
 
 // 3rd-party imports
 mod errors;
-use log::{debug, trace};
-use structopt::{clap, StructOpt};
+use log::trace;
+use structopt::StructOpt;
 
 // Local imports
 mod app;
@@ -78,17 +77,6 @@ fn main() {
         .expect("initializing logging output");
     trace!("Initialized logging");
 
-    // If requested, generate shell completions and then exit with status of "success"
-    if let Some(shell) = opts.boilerplate.dump_completions {
-        debug!("Request to dump completion for {}", shell);
-        app::CliOpts::clap().gen_completions_to(
-            app::CliOpts::clap().get_bin_name().unwrap_or_else(|| clap::crate_name!()),
-            shell,
-            &mut io::stdout(),
-        );
-        std::process::exit(0);
-    };
-
     trace!("Starting with application");
     if let Err(ref e) = app::main(opts) {
         use std::io::prelude::*;