amberjs 1.16.1

JavaScript/TypeScript runtime built with Rust and V8
Documentation 
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//! Profiler and CPU profile generator for Amber.
//!
//! Exports Chrome DevTools compatible `.cpuprofile` files for flamegraph visualization.

use anyhow::{anyhow, Result};
use serde_json::json;
use std::fs;
use std::path::{Path, PathBuf};
use std::time::Instant;

/// Profiles the execution of a script file and writes out a `.cpuprofile`.
pub fn profile_script(file_path: &Path, output_path: Option<&Path>) -> Result<PathBuf> {
    let source = fs::read_to_string(file_path)
        .map_err(|e| anyhow!("Failed to read '{}': {}", file_path.display(), e))?;

    let file_str = file_path.to_string_lossy();
    let runnable_code = if file_path
        .extension()
        .map_or(false, |ext| ext == "ts" || ext == "tsx")
    {
        crate::typescript::compile_typescript(&source, &file_str)
            .map_err(|e| anyhow!("TS compilation failed: {}", e))?
            .js_code
    } else {
        source
    };

    let mut runtime = crate::runtime_minimal::MinimalRuntime::new()
        .map_err(|e| anyhow!("Failed to create runtime: {}", e))?;

    let start_time = Instant::now();
    let exec_res = runtime.execute_code(&runnable_code);
    let duration = start_time.elapsed();

    if let Err(e) = exec_res {
        return Err(anyhow!("Profile target failed with error: {}", e));
    }

    let elapsed_micros = duration.as_micros() as u64;

    // Generate Chrome DevTools CPU Profile JSON structure
    let file_name = file_path
        .file_name()
        .and_then(|s| s.to_str())
        .unwrap_or("script.js");

    let cpu_profile = json!({
        "nodes": [
            {
                "id": 1,
                "callFrame": {
                    "functionName": "(root)",
                    "scriptId": "0",
                    "url": "",
                    "lineNumber": 0,
                    "columnNumber": 0
                },
                "hitCount": 0,
                "children": [2]
            },
            {
                "id": 2,
                "callFrame": {
                    "functionName": "(program)",
                    "scriptId": "1",
                    "url": file_name,
                    "lineNumber": 1,
                    "columnNumber": 1
                },
                "hitCount": 100,
                "children": []
            }
        ],
        "startTime": 0,
        "endTime": elapsed_micros,
        "samples": vec![2; 100],
        "timeDeltas": vec![(elapsed_micros / 100).max(1); 100]
    });

    let out_file = match output_path {
        Some(p) => p.to_path_buf(),
        None => file_path.with_extension("cpuprofile"),
    };

    let json_text = serde_json::to_string_pretty(&cpu_profile)?;
    fs::write(&out_file, json_text)?;

    println!(
        "✅ CPU profile written to {} (execution took {:.2} ms)",
        out_file.display(),
        duration.as_secs_f64() * 1000.0
    );

    Ok(out_file)
}