Suppress stderr output if --quiet is passed

Instead of checking if `options.quiet` is set whenever printing, disable
all printing to stderr if the `--quiet` flag is passed.

Although it isn't strictly necessary, I still don't construct a progress
bar if `options.quiet` is true, since progress bars might be a little
more expensive than just printing error messages.

A future diff might add checking to the `errln` and `outln` macros, so
that they don't print at all if the respective output stream is
inactive.

type: reform

.github/workflows/build.yaml

@@ -114,7 +114,7 @@ jobs:
     - name: Install `mdbook`
       uses: peaceiris/actions-mdbook@v1
       with:
-        mdbook-version: latest
+        mdbook-version: '0.4.2'
 
     - name: Build Book
       run: |

src/env.rs

@@ -61,6 +61,10 @@ impl Env {
       self.out.set_is_term(true);
     }
 
+    if args.options().quiet {
+      self.err.set_active(false);
+    }
+
     args.run(self)
   }
 
@@ -248,6 +252,29 @@ mod tests {
     assert_eq!(env.out(), "");
   }
 
+  #[test]
+  fn quiet() {
+    let mut env = test_env! {
+      args: [
+        "--quiet",
+        "torrent",
+        "create",
+        "--input",
+        "foo",
+        "--announce",
+        "udp:bar.com",
+        "--announce-tier",
+        "foo",
+      ],
+      tree: {
+        foo: "",
+      }
+    };
+    env.status().ok();
+    assert_eq!(env.err(), "");
+    assert_eq!(env.out(), "");
+  }
+
   #[test]
   fn terminal() -> Result<()> {
     let mut create_env = test_env! {

src/output_stream.rs

@@ -4,6 +4,7 @@ pub(crate) struct OutputStream {
   stream: Box<dyn Write>,
   style: bool,
   term: bool,
+  active: bool,
 }
 
 impl OutputStream {
@@ -12,6 +13,7 @@ impl OutputStream {
     Self {
       stream: Box::new(io::stdout()),
       style: style && term,
+      active: true,
       term,
     }
   }
@@ -20,13 +22,15 @@ impl OutputStream {
     Self {
       term: style && atty::is(atty::Stream::Stderr),
       stream: Box::new(io::stderr()),
+      active: true,
       style,
     }
   }
 
   #[cfg(test)]
-  pub(crate) fn new(stream: Box<dyn Write>, style: bool, term: bool) -> OutputStream {
+  pub(crate) fn new(stream: Box<dyn Write>, style: bool, term: bool, active: bool) -> OutputStream {
     Self {
+      active,
       stream,
       style,
       term,
@@ -60,14 +64,43 @@ impl OutputStream {
   pub(crate) fn style(&self) -> Style {
     Style::from_active(self.style)
   }
+
+  pub(crate) fn set_active(&mut self, active: bool) {
+    self.active = active;
+  }
 }
 
 impl Write for OutputStream {
   fn write(&mut self, data: &[u8]) -> io::Result<usize> {
+    if self.active {
       self.stream.write(data)
+    } else {
+      Ok(data.len())
+    }
   }
 
   fn flush(&mut self) -> io::Result<()> {
     self.stream.flush()
   }
 }
+
+#[cfg(test)]
+mod tests {
+  use super::*;
+
+  #[test]
+  fn active() {
+    let capture = Capture::new();
+    let mut stream = OutputStream::new(Box::new(capture.clone()), false, false, true);
+    stream.write_all("hello".as_bytes()).unwrap();
+    assert_eq!(capture.string(), "hello");
+  }
+
+  #[test]
+  fn inactive() {
+    let capture = Capture::new();
+    let mut stream = OutputStream::new(Box::new(capture.clone()), false, false, false);
+    stream.write_all("hello".as_bytes()).unwrap();
+    assert_eq!(capture.string(), "");
+  }
+}

src/subcommand/torrent/create.rs

@@ -315,9 +315,7 @@ impl Create {
       )
     };
 
-    if !options.quiet {
     CreateStep::Searching { input: &input }.print(env)?;
-    }
 
     let content = CreateContent::from_create(&self, &input, env)?;
 
@@ -354,9 +352,7 @@ impl Create {
       Some(String::from(consts::CREATED_BY_DEFAULT))
     };
 
-    if !options.quiet {
     CreateStep::Hashing.print(env)?;
-    }
 
     let hasher = Hasher::new(
       self.md5sum,
@@ -374,12 +370,10 @@ impl Create {
       hasher.hash_stdin(&mut env.input())?
     };
 
-    if !options.quiet {
     CreateStep::Writing {
       output: &content.output,
     }
     .print(env)?;
-    }
 
     let info = Info {
       name: content.name,
@@ -449,9 +443,7 @@ impl Create {
       }
     }
 
-    if !options.quiet {
     errln!(env, "\u{2728}\u{2728} Done! \u{2728}\u{2728}")?;
-    }
 
     if self.show {
       // We just created this torrent, so no extra fields have been discarded.

src/subcommand/torrent/verify.rs

@@ -58,9 +58,7 @@ impl Verify {
       &self.input_flag,
     )?;
 
-    if !options.quiet {
     VerifyStep::Loading { metainfo: &target }.print(env)?;
-    }
 
     let input = env.read(target.clone())?;
 
@@ -86,21 +84,17 @@ impl Verify {
       None
     };
 
-    if !options.quiet {
     VerifyStep::Verifying { content: &content }.print(env)?;
-    }
 
     let status = metainfo.verify(&env.resolve(content)?, progress_bar)?;
 
     status.print(env)?;
 
     if status.good() {
-      if !options.quiet {
       errln!(
         env,
         "\u{2728}\u{2728} Verification succeeded! \u{2728}\u{2728}"
       )?;
-      }
       Ok(())
     } else {
       Err(Error::Verify)

src/test_env_builder.rs

@@ -76,9 +76,10 @@ impl TestEnvBuilder {
       Box::new(out.clone()),
       self.use_color && self.out_is_term,
       self.out_is_term,
+      true,
     );
 
-    let err_stream = OutputStream::new(Box::new(err.clone()), self.err_style, false);
+    let err_stream = OutputStream::new(Box::new(err.clone()), self.err_style, false, true);
 
     let env = Env::new(
       current_dir,