Add --dot flag to parse subcommand, for printing tree as DOT graph

cli/src/util.rs

@@ -3,7 +3,7 @@ use std::io;
 use std::sync::atomic::{AtomicUsize, Ordering};
 use std::sync::Arc;
 use std::thread;
-use tree_sitter::Parser;
+use tree_sitter::{Parser, Tree};
 
 #[cfg(unix)]
 use anyhow::{anyhow, Context};
@@ -29,39 +29,61 @@ pub fn cancel_on_stdin() -> Arc<AtomicUsize> {
     }
     result
 }
+
 #[cfg(windows)]
-pub struct LogSession();
+pub struct LogSession;
 
 #[cfg(unix)]
-pub struct LogSession(PathBuf, Option<Child>, Option<ChildStdin>);
+pub struct LogSession {
+    path: PathBuf,
+    dot_process: Option<Child>,
+    dot_process_stdin: Option<ChildStdin>,
+}
+
+pub fn print_tree_graph(tree: &Tree, path: &str) -> Result<()> {
+    let session = LogSession::new(path)?;
+    tree.print_dot_graph(session.dot_process_stdin.as_ref().unwrap());
+    Ok(())
+}
+
+pub fn log_graphs(parser: &mut Parser, path: &str) -> Result<LogSession> {
+    let session = LogSession::new(path)?;
+    parser.print_dot_graphs(session.dot_process_stdin.as_ref().unwrap());
+    Ok(session)
+}
 
 #[cfg(windows)]
-pub fn log_graphs(_parser: &mut Parser, _path: &str) -> Result<LogSession> {
-    Ok(LogSession())
+impl LogSession {
+    fn new(path: &str) -> Result<Self> {
+        Ok(Self)
+    }
 }
 
 #[cfg(unix)]
-pub fn log_graphs(parser: &mut Parser, path: &str) -> Result<LogSession> {
-    use std::io::Write;
+impl LogSession {
+    fn new(path: &str) -> Result<Self> {
+        use std::io::Write;
 
-    let mut dot_file = std::fs::File::create(path)?;
-    dot_file.write(HTML_HEADER)?;
-    let mut dot_process = Command::new("dot")
-        .arg("-Tsvg")
-        .stdin(Stdio::piped())
-        .stdout(dot_file)
-        .spawn()
-        .with_context(|| "Failed to run the `dot` command. Check that graphviz is installed.")?;
-    let dot_stdin = dot_process
-        .stdin
-        .take()
-        .ok_or_else(|| anyhow!("Failed to open stdin for `dot` process."))?;
-    parser.print_dot_graphs(&dot_stdin);
-    Ok(LogSession(
-        PathBuf::from(path),
-        Some(dot_process),
-        Some(dot_stdin),
-    ))
+        let mut dot_file = std::fs::File::create(path)?;
+        dot_file.write(HTML_HEADER)?;
+        let mut dot_process = Command::new("dot")
+            .arg("-Tsvg")
+            .stdin(Stdio::piped())
+            .stdout(dot_file)
+            .spawn()
+            .with_context(|| {
+                "Failed to run the `dot` command. Check that graphviz is installed."
+            })?;
+        let dot_stdin = dot_process
+            .stdin
+            .take()
+            .ok_or_else(|| anyhow!("Failed to open stdin for `dot` process."))?;
+        Ok(Self {
+            path: PathBuf::from(path),
+            dot_process: Some(dot_process),
+            dot_process_stdin: Some(dot_stdin),
+        })
+    }
 }
 
 #[cfg(unix)]
@@ -69,13 +91,13 @@ impl Drop for LogSession {
     fn drop(&mut self) {
         use std::fs;
 
-        drop(self.2.take().unwrap());
-        let output = self.1.take().unwrap().wait_with_output().unwrap();
+        drop(self.dot_process_stdin.take().unwrap());
+        let output = self.dot_process.take().unwrap().wait_with_output().unwrap();
         if output.status.success() {
             if cfg!(target_os = "macos")
-                && fs::metadata(&self.0).unwrap().len() > HTML_HEADER.len() as u64
+                && fs::metadata(&self.path).unwrap().len() > HTML_HEADER.len() as u64
             {
-                Command::new("open").arg(&self.0).output().unwrap();
+                Command::new("open").arg(&self.path).output().unwrap();
             }
         } else {
             eprintln!(