Refactor logging for a DRYer, unified interface

src/main.rs

@@ -1,13 +1,12 @@
-//! `word-tally` tallies and outputs the count of words from a file or streamed input.
+//! `word-tally` tallies and outputs the count of words from a given input.
 
 pub(crate) mod args;
 
 use anyhow::{Context, Result};
 use args::Args;
 use clap::Parser;
-use clap_stdin::Source;
 use std::fs::File;
-use std::io::{self, ErrorKind::BrokenPipe, LineWriter, StderrLock, Write};
+use std::io::{self, ErrorKind::BrokenPipe, LineWriter, Write};
 use unescaper::unescape;
 use word_tally::{Minimums, WordTally};
 
@@ -43,73 +42,38 @@ fn log_details(
     args: &Args,
     delimiter: &str,
 ) -> Result<()> {
-    let mut stderr_lock = stderr.lock();
+    let mut w = Box::new(stderr.lock()) as Writer;
 
     if args.verbose {
-        log_verbose(
-            &mut stderr_lock,
-            word_tally.count(),
-            word_tally.uniq_count(),
-            word_tally.avg(),
-            &args.input.source,
+        log_detail(
+            &mut w,
+            "source",
             delimiter,
+            format!("{:?}", args.input.source),
         )?;
+        log_detail(&mut w, "total-words", delimiter, word_tally.count())?;
+        log_detail(&mut w, "unique-words", delimiter, word_tally.uniq_count())?;
+
+        if let Some(avg) = word_tally.avg() {
+            log_detail(&mut w, "average-word-count", delimiter, format!("{avg:.3}"))?;
+        }
     }
 
     if args.debug {
-        log_debug(&mut stderr_lock, args, delimiter)?;
+        log_detail(&mut w, "delimiter", delimiter, format!("{delimiter:?}"))?;
+        log_detail(&mut w, "case", delimiter, args.case)?;
+        log_detail(&mut w, "order", delimiter, args.sort)?;
+        log_detail(&mut w, "min-chars", delimiter, args.min_chars)?;
+        log_detail(&mut w, "min-count", delimiter, args.min_count)?;
+        log_detail(&mut w, "verbose", delimiter, args.verbose)?;
+        log_detail(&mut w, "debug", delimiter, args.debug)?;
     }
 
     if word_tally.count() > 0 {
-        piping(stderr_lock.write_all(b"\n"))?;
-    }
-
-    piping(stderr_lock.flush())?;
-
-    Ok(())
-}
-
-/// Log verbose details to stderr.
-fn log_verbose(
-    stderr: &mut StderrLock<'_>,
-    count: u64,
-    uniq_count: usize,
-    maybe_avg: Option<f64>,
-    source: &Source,
-    delimiter: &str,
-) -> Result<()> {
-    let details = [
-        format!("source{delimiter}{source:#?}\n"),
-        format!("total-words{delimiter}{count}\n"),
-        format!("unique-words{delimiter}{uniq_count}\n"),
-    ];
-
-    for detail in &details {
-        piping(stderr.write_all(detail.as_bytes()))?;
+        log(&mut w, "\n")?;
     }
 
-    if let Some(avg) = maybe_avg {
-        piping(stderr.write_all(format!("average-word-count{delimiter}{avg:.3}\n").as_bytes()))?;
-    }
-
-    Ok(())
-}
-
-/// Log debug details to stderr.
-fn log_debug(stderr: &mut StderrLock<'_>, args: &Args, delimiter: &str) -> Result<()> {
-    let details = [
-        format!("delimiter{delimiter}{delimiter:#?}\n"),
-        format!("case{delimiter}{}\n", args.case),
-        format!("order{delimiter}{}\n", args.sort),
-        format!("min-chars{delimiter}{}\n", args.min_chars),
-        format!("min-count{delimiter}{}\n", args.min_count),
-        format!("verbose{delimiter}{}\n", args.verbose),
-        format!("debug{delimiter}{}\n", args.debug),
-    ];
-
-    for detail in &details {
-        piping(stderr.write_all(detail.as_bytes()))?;
-    }
+    piping(w.flush())?;
 
     Ok(())
 }
@@ -121,23 +85,41 @@ fn write_tally(
     args: &Args,
     delimiter: &str,
 ) -> Result<()> {
-    let mut writer: Writer = match &args.output {
+    let mut w: Writer = match &args.output {
         Some(path) => Box::new(LineWriter::new(File::create(path)?)),
         None => Box::new(stdout.lock()),
     };
 
     for (word, count) in word_tally.tally() {
         let line = format!("{word}{delimiter}{count}\n");
-        piping(writer.write_all(line.as_bytes()))?;
+        log(&mut w, &line)?;
     }
 
-    piping(writer.flush())?;
+    piping(w.flush())?;
+
+    Ok(())
+}
+
+/// Log a formatted details line.
+fn log_detail<T: std::fmt::Display>(
+    w: &mut Writer,
+    label: &str,
+    delimiter: &str,
+    value: T,
+) -> Result<()> {
+    let line = format!("{label}{delimiter}{value}\n");
+
+    log(w, &line)
+}
+
+/// Log a line.
+fn log(w: &mut Writer, line: &str) -> Result<()> {
+    piping(w.write_all(line.as_bytes()))?;
 
     Ok(())
 }
 
-/// Processes the result of a write operation, handling `BrokenPipe` errors
-/// gracefully.
+/// Processes the result of a write, handling `BrokenPipe` errors gracefully.
 // This can be simplified once `-Zon-broken-pipe=kill` stabilizes and can be
 // used to kill the program if it tries to write to a closed pipe.
 fn piping(result: std::io::Result<()>) -> Result<()> {