Allow positional input to imdl torrent show

Input can now be passed to `imdl torrent show` without a flag:

  imdl torrent show foo.torrent

Passing input by flag continues to work.

type: changed
fixes:
- https://github.com/casey/intermodal/issues/375

CHANGELOG.md

@@ -4,7 +4,8 @@ Changelog
 
 UNRELEASED - 2020-04-22
 -----------------------
-- :bug: [`xxxxxxxxxxxx`](https://github.com/casey/intermodal/commits/master) Fix help strings - _Casey Rodarmor <casey@rodarmor.com>_
+- :zap: [`xxxxxxxxxxxx`](https://github.com/casey/intermodal/commits/master) Allow positional input to `imdl torrent show` - Fixes [#375](https://github.com/casey/intermodal/issues/375) - _Casey Rodarmor <casey@rodarmor.com>_
+- :bug: [`cecd2f66a5d6`](https://github.com/casey/intermodal/commit/cecd2f66a5d6a6b44f27f8ca499e359d82d29ab7) Fix help strings - _Casey Rodarmor <casey@rodarmor.com>_
 - :zap: [`ebec2d591a7a`](https://github.com/casey/intermodal/commit/ebec2d591a7a0e2a2c4cd55217db4ba46b5dd9ed) Allow positional shell to `imdl completions` - Fixes [#375](https://github.com/casey/intermodal/issues/375) - _Casey Rodarmor <casey@rodarmor.com>_
 - :art: [`134c241ae7f8`](https://github.com/casey/intermodal/commit/134c241ae7f8e374d8a9266e7eb0c4a9c3844c30) Use `lexiclean` crate for lexical path cleaning - _Casey Rodarmor <casey@rodarmor.com>_
 - :zap: [`323434d0aa21`](https://github.com/casey/intermodal/commit/323434d0aa21ebfda5be85ecd4a38a55ed3fec0a) Allow positional input to `imdl torrent verify` - Fixes [#375](https://github.com/casey/intermodal/issues/375) - _Casey Rodarmor <casey@rodarmor.com>_

src/subcommand/torrent/link.rs

@@ -68,7 +68,7 @@ impl Link {
       &self.input_positional,
     )?;
 
-    let input = env.read(input.clone())?;
+    let input = env.read(input)?;
 
     let infohash = Infohash::from_input(&input)?;
     let metainfo = Metainfo::from_input(&input)?;

src/subcommand/torrent/show.rs

@@ -1,5 +1,14 @@
 use crate::common::*;
 
+const INPUT_HELP: &str = "Show information about torrent at `INPUT`. If `INPUT` is `-`, read \
+                          torrent metainfo from standard input.";
+
+const INPUT_FLAG: &str = "input-flag";
+
+const INPUT_POSITIONAL: &str = "<INPUT>";
+
+const INPUT_VALUE: &str = "INPUT";
+
 #[derive(StructOpt)]
 #[structopt(
   help_message(consts::HELP_MESSAGE),
@@ -8,20 +17,37 @@ use crate::common::*;
 )]
 pub(crate) struct Show {
   #[structopt(
+    name = INPUT_FLAG,
     long = "input",
     short = "i",
-    value_name = "PATH",
+    value_name = INPUT_VALUE,
     empty_values(false),
     parse(try_from_os_str = InputTarget::try_from_os_str),
-    help = "Show information about torrent at `PATH`. If `Path` is `-`, read torrent metainfo \
-            from standard input.",
+    help = INPUT_HELP,
   )]
-  input: InputTarget,
+  input_flag: Option<InputTarget>,
+  #[structopt(
+    name = INPUT_POSITIONAL,
+    value_name = INPUT_VALUE,
+    empty_values(false),
+    parse(try_from_os_str = InputTarget::try_from_os_str),
+    required_unless = INPUT_FLAG,
+    conflicts_with = INPUT_FLAG,
+    help = INPUT_HELP,
+  )]
+  input_positional: Option<InputTarget>,
 }
 
 impl Show {
   pub(crate) fn run(self, env: &mut Env) -> Result<(), Error> {
-    let input = env.read(self.input)?;
+    let target = xor_args(
+      "input_flag",
+      &self.input_flag,
+      "input_positional",
+      &self.input_positional,
+    )?;
+
+    let input = env.read(target)?;
     let summary = TorrentSummary::from_input(&input)?;
     summary.write(env)?;
     Ok(())
@@ -34,6 +60,55 @@ mod tests {
 
   use pretty_assertions::assert_eq;
 
+  #[test]
+  fn input_required() {
+    test_env! {
+      args: [
+        "torrent",
+        "show",
+      ],
+      tree: {
+      },
+      matches: Err(Error::Clap { .. }),
+    };
+
+    test_env! {
+      args: [
+        "torrent",
+        "show",
+        "--input",
+        "foo",
+      ],
+      tree: {
+      },
+      matches: Err(Error::Filesystem { .. }),
+    };
+
+    test_env! {
+      args: [
+        "torrent",
+        "show",
+        "foo",
+      ],
+      tree: {
+      },
+      matches: Err(Error::Filesystem { .. }),
+    };
+
+    test_env! {
+      args: [
+        "torrent",
+        "show",
+        "--input",
+        "foo",
+        "foo",
+      ],
+      tree: {
+      },
+      matches: Err(Error::Clap { .. }),
+    };
+  }
+
   #[test]
   fn output() -> Result<()> {
     let metainfo = Metainfo {
@@ -99,6 +174,44 @@ Announce List  Tier 1: announce
       assert_eq!(have, want);
     }
 
+    {
+      let mut env = TestEnvBuilder::new()
+        .arg_slice(&["imdl", "torrent", "show", "foo.torrent"])
+        .out_is_term()
+        .build();
+
+      let path = env.resolve("foo.torrent")?;
+
+      metainfo.dump(path).unwrap();
+
+      env.assert_ok();
+
+      let have = env.out();
+      let want = "         Name  foo
+      Comment  comment
+Creation Date  1970-01-01 00:00:01 UTC
+   Created By  created by
+       Source  source
+    Info Hash  e12253978dc6d50db11d05747abcea1ad03b51c5
+ Torrent Size  339 bytes
+ Content Size  20 bytes
+      Private  yes
+      Tracker  announce
+Announce List  Tier 1: announce
+                       b
+               Tier 2: c
+    DHT Nodes  x:12
+               1.1.1.1:16
+               [2001:db8:85a3::8a2e:370]:7334
+   Piece Size  16 KiB
+  Piece Count  2
+   File Count  1
+        Files  foo
+";
+
+      assert_eq!(have, want);
+    }
+
     {
       let mut env = TestEnvBuilder::new()
         .arg_slice(&["imdl", "torrent", "show", "--input", "foo.torrent"])