feat(cli): implement --format checkstyle (#3044)

closes #2355

crates/oxc_cli/src/command/lint.rs

@@ -145,6 +145,7 @@ pub enum OutputFormat {
     Default,
     Json,
     Unix,
+    Checkstyle,
 }
 
 impl FromStr for OutputFormat {
@@ -154,6 +155,7 @@ impl FromStr for OutputFormat {
             "json" => Ok(Self::Json),
             "default" => Ok(Self::Default),
             "unix" => Ok(Self::Unix),
+            "checkstyle" => Ok(Self::Checkstyle),
             _ => Err(format!("'{s}' is not a known format")),
         }
     }

crates/oxc_cli/src/lint/mod.rs

@@ -164,8 +164,8 @@ impl LintRunner {
             OutputFormat::Default => {}
             OutputFormat::Json => diagnostic_service.set_json_reporter(),
             OutputFormat::Unix => diagnostic_service.set_unix_reporter(),
+            OutputFormat::Checkstyle => diagnostic_service.set_checkstyle_reporter(),
         }
-
         diagnostic_service
     }
 }

crates/oxc_diagnostics/src/reporter.rs

@@ -1,4 +1,8 @@
-use std::io::{BufWriter, Stdout, Write};
+use std::{
+    borrow::Cow,
+    collections::HashMap,
+    io::{BufWriter, Stdout, Write},
+};
 
 use crate::{
     miette::{Error, JSONReportHandler},
@@ -18,6 +22,7 @@ pub enum DiagnosticReporter {
     Graphical { handler: GraphicalReportHandler, writer: BufWriter<Stdout> },
     Json { diagnostics: Vec<Error> },
     Unix { total: usize, writer: BufWriter<Stdout> },
+    Checkstyle { diagnostics: Vec<Error> },
 }
 
 impl DiagnosticReporter {
@@ -33,6 +38,10 @@ impl DiagnosticReporter {
         Self::Unix { total: 0, writer: writer() }
     }
 
+    pub fn new_checkstyle() -> Self {
+        Self::Checkstyle { diagnostics: vec![] }
+    }
+
     pub fn finish(&mut self) {
         match self {
             Self::Graphical { writer, .. } => {
@@ -50,6 +59,9 @@ impl DiagnosticReporter {
                 }
                 writer.flush().unwrap();
             }
+            Self::Checkstyle { diagnostics } => {
+                format_checkstyle(diagnostics);
+            }
         }
     }
 
@@ -58,7 +70,7 @@ impl DiagnosticReporter {
             Self::Graphical { writer, .. } | Self::Unix { writer, .. } => {
                 writer.write_all(s).unwrap();
             }
-            Self::Json { .. } => {}
+            Self::Json { .. } | Self::Checkstyle { .. } => {}
         }
     }
 
@@ -69,7 +81,7 @@ impl DiagnosticReporter {
                 handler.render_report(&mut output, error.as_ref()).unwrap();
                 Some(output)
             }
-            Self::Json { diagnostics } => {
+            Self::Json { diagnostics } | Self::Checkstyle { diagnostics } => {
                 diagnostics.push(error);
                 None
             }
@@ -81,6 +93,49 @@ impl DiagnosticReporter {
     }
 }
 
+struct Info {
+    line: usize,
+    column: usize,
+    filename: String,
+    message: String,
+    severity: Severity,
+    rule_id: Option<String>,
+}
+
+impl Info {
+    fn new(diagnostic: &Error) -> Self {
+        let mut line = 0;
+        let mut column = 0;
+        let mut filename = String::new();
+        let mut message = String::new();
+        let mut severity = Severity::Warning;
+        let mut rule_id = None;
+        if let Some(mut labels) = diagnostic.labels() {
+            if let Some(source) = diagnostic.source_code() {
+                if let Some(label) = labels.next() {
+                    if let Ok(span_content) = source.read_span(label.inner(), 0, 0) {
+                        line = span_content.line() + 1;
+                        column = span_content.column() + 1;
+                        if let Some(name) = span_content.name() {
+                            filename = name.to_string();
+                        };
+                        if matches!(diagnostic.severity(), Some(Severity::Error)) {
+                            severity = Severity::Error;
+                        }
+                        let msg = diagnostic.to_string();
+                        // Our messages usually comes with `eslint(rule): message`
+                        (rule_id, message) = msg.split_once(':').map_or_else(
+                            || (None, msg.to_string()),
+                            |(id, msg)| (Some(id.to_string()), msg.trim().to_string()),
+                        );
+                    }
+                }
+            }
+        }
+        Self { line, column, filename, message, severity, rule_id }
+    }
+}
+
 /// <https://github.com/fregante/eslint-formatters/tree/main/packages/eslint-formatter-json>
 fn format_json(diagnostics: &mut Vec<Error>) {
     let handler = JSONReportHandler::new();
@@ -98,33 +153,92 @@ fn format_json(diagnostics: &mut Vec<Error>) {
 
 /// <https://github.com/fregante/eslint-formatters/tree/main/packages/eslint-formatter-unix>
 fn format_unix(diagnostic: &Error) -> String {
-    let mut line = 0;
-    let mut column = 0;
-    let mut filename = String::new();
-    let mut message = String::new();
-    let mut severity = "Warning";
-    let mut rule_id = String::new();
-    if let Some(mut labels) = diagnostic.labels() {
-        if let Some(source) = diagnostic.source_code() {
-            if let Some(label) = labels.next() {
-                if let Ok(span_content) = source.read_span(label.inner(), 0, 0) {
-                    line = span_content.line() + 1;
-                    column = span_content.column() + 1;
-                    if let Some(name) = span_content.name() {
-                        filename = name.to_string();
-                    };
-                    if matches!(diagnostic.severity(), Some(Severity::Error)) {
-                        severity = "Warning";
-                    }
-                    let msg = diagnostic.to_string();
-                    // Our messages usually comes with `eslint(rule): message`
-                    (rule_id, message) = msg.split_once(':').map_or_else(
-                        || (String::new(), msg.to_string()),
-                        |(id, msg)| (id.to_string(), msg.trim().to_string()),
-                    );
-                }
-            }
+    let Info { line, column, filename, message, severity, rule_id } = Info::new(diagnostic);
+    let severity = match severity {
+        Severity::Error => "Error",
+        _ => "Warning",
+    };
+    let rule_id =
+        rule_id.map_or_else(|| Cow::Borrowed(""), |rule_id| Cow::Owned(format!("/{rule_id}")));
+    format!("{filename}:{line}:{column}: {message} [{severity}{rule_id}]\n")
+}
+
+fn format_checkstyle(diagnostics: &[Error]) {
+    let infos = diagnostics.iter().map(Info::new).collect::<Vec<_>>();
+    let mut grouped: HashMap<String, Vec<Info>> = HashMap::new();
+    for info in infos {
+        grouped.entry(info.filename.clone()).or_default().push(info);
+    }
+    let messages = grouped.into_values().map(|infos| {
+         let messages = infos
+             .iter()
+             .fold(String::new(), |mut acc, info| {
+                 let Info { line, column, message, severity, rule_id, .. } = info;
+                 let severity = match severity {
+                     Severity::Error => "error",
+                     _ => "warning",
+                 };
+                 let message = rule_id.as_ref().map_or_else(|| xml_escape(message), |rule_id| Cow::Owned(format!("{} ({rule_id})", xml_escape(message))));
+                 let source = rule_id.as_ref().map_or_else(|| Cow::Borrowed(""), |rule_id| Cow::Owned(format!("eslint.rules.{rule_id}")));
+                 let line = format!(r#"<error line="{line}" column="{column}" severity="{severity}" message="{message}" source="{source}" />"#);
+                 acc.push_str(&line);
+                 acc
+             });
+         let filename = &infos[0].filename;
+         format!(r#"<file name="{filename}">{messages}</file>"#)
+     }).collect::<Vec<_>>().join(" ");
+    println!(
+        r#"<?xml version="1.0" encoding="utf-8"?><checkstyle version="4.3">{messages}</checkstyle>"#
+    );
+}
+
+/// <https://github.com/tafia/quick-xml/blob/6e34a730853fe295d68dc28460153f08a5a12955/src/escapei.rs#L84-L86>
+fn xml_escape(raw: &str) -> Cow<str> {
+    xml_escape_impl(raw, |ch| matches!(ch, b'<' | b'>' | b'&' | b'\'' | b'\"'))
+}
+
+fn xml_escape_impl<F: Fn(u8) -> bool>(raw: &str, escape_chars: F) -> Cow<str> {
+    let bytes = raw.as_bytes();
+    let mut escaped = None;
+    let mut iter = bytes.iter();
+    let mut pos = 0;
+    while let Some(i) = iter.position(|&b| escape_chars(b)) {
+        if escaped.is_none() {
+            escaped = Some(Vec::with_capacity(raw.len()));
+        }
+        let escaped = escaped.as_mut().expect("initialized");
+        let new_pos = pos + i;
+        escaped.extend_from_slice(&bytes[pos..new_pos]);
+        match bytes[new_pos] {
+            b'<' => escaped.extend_from_slice(b"&lt;"),
+            b'>' => escaped.extend_from_slice(b"&gt;"),
+            b'\'' => escaped.extend_from_slice(b"&apos;"),
+            b'&' => escaped.extend_from_slice(b"&amp;"),
+            b'"' => escaped.extend_from_slice(b"&quot;"),
+
+            // This set of escapes handles characters that should be escaped
+            // in elements of xs:lists, because those characters works as
+            // delimiters of list elements
+            b'\t' => escaped.extend_from_slice(b"&#9;"),
+            b'\n' => escaped.extend_from_slice(b"&#10;"),
+            b'\r' => escaped.extend_from_slice(b"&#13;"),
+            b' ' => escaped.extend_from_slice(b"&#32;"),
+            _ => unreachable!(
+                "Only '<', '>','\', '&', '\"', '\\t', '\\r', '\\n', and ' ' are escaped"
+            ),
+        }
+        pos = new_pos + 1;
+    }
+
+    if let Some(mut escaped) = escaped {
+        if let Some(raw) = bytes.get(pos..) {
+            escaped.extend_from_slice(raw);
         }
+        #[allow(unsafe_code)]
+        // SAFETY: we operate on UTF-8 input and search for an one byte chars only,
+        // so all slices that was put to the `escaped` is a valid UTF-8 encoded strings
+        Cow::Owned(unsafe { String::from_utf8_unchecked(escaped) })
+    } else {
+        Cow::Borrowed(raw)
     }
-    format!("{filename}:{line}:{column}: {message} [{severity}/{rule_id}]\n")
 }

crates/oxc_diagnostics/src/service.rs

@@ -56,6 +56,10 @@ impl DiagnosticService {
         self.reporter = DiagnosticReporter::new_unix();
     }
 
+    pub fn set_checkstyle_reporter(&mut self) {
+        self.reporter = DiagnosticReporter::new_checkstyle();
+    }
+
     pub fn is_graphical_output(&self) -> bool {
         matches!(self.reporter, DiagnosticReporter::Graphical { .. })
     }