denoland-deno/cli/tools/coverage/mod.rs

// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.

use crate::args::CoverageFlags;
use crate::args::CoverageType;
use crate::args::FileFlags;
use crate::args::Flags;
use crate::cdp;
use crate::colors;
use crate::factory::CliFactory;
use crate::npm::CliNpmResolver;
use crate::tools::fmt::format_json;
use crate::tools::test::is_supported_test_path;
use crate::util::fs::FileCollector;
use crate::util::text_encoding::source_map_from_code;

use deno_ast::MediaType;
use deno_ast::ModuleSpecifier;
use deno_core::anyhow::anyhow;
use deno_core::anyhow::Context;
use deno_core::error::generic_error;
use deno_core::error::AnyError;
use deno_core::serde_json;
use deno_core::sourcemap::SourceMap;
use deno_core::url::Url;
use deno_core::LocalInspectorSession;
use deno_core::ModuleCode;
use regex::Regex;
use std::collections::HashMap;
use std::fs;
use std::fs::File;
use std::io::BufWriter;
use std::io::Error;
use std::io::Write;
use std::io::{self};
use std::path::Path;
use std::path::PathBuf;
use text_lines::TextLines;
use uuid::Uuid;

mod merge;
mod range_tree;
mod util;
use merge::ProcessCoverage;

pub struct CoverageCollector {
  pub dir: PathBuf,
  session: LocalInspectorSession,
}

impl CoverageCollector {
  pub fn new(dir: PathBuf, session: LocalInspectorSession) -> Self {
    Self { dir, session }
  }

  async fn enable_debugger(&mut self) -> Result<(), AnyError> {
    self
      .session
      .post_message::<()>("Debugger.enable", None)
      .await?;
    Ok(())
  }

  async fn enable_profiler(&mut self) -> Result<(), AnyError> {
    self
      .session
      .post_message::<()>("Profiler.enable", None)
      .await?;
    Ok(())
  }

  async fn disable_debugger(&mut self) -> Result<(), AnyError> {
    self
      .session
      .post_message::<()>("Debugger.disable", None)
      .await?;
    Ok(())
  }

  async fn disable_profiler(&mut self) -> Result<(), AnyError> {
    self
      .session
      .post_message::<()>("Profiler.disable", None)
      .await?;
    Ok(())
  }

  async fn start_precise_coverage(
    &mut self,
    parameters: cdp::StartPreciseCoverageArgs,
  ) -> Result<cdp::StartPreciseCoverageResponse, AnyError> {
    let return_value = self
      .session
      .post_message("Profiler.startPreciseCoverage", Some(parameters))
      .await?;

    let return_object = serde_json::from_value(return_value)?;

    Ok(return_object)
  }

  async fn take_precise_coverage(
    &mut self,
  ) -> Result<cdp::TakePreciseCoverageResponse, AnyError> {
    let return_value = self
      .session
      .post_message::<()>("Profiler.takePreciseCoverage", None)
      .await?;

    let return_object = serde_json::from_value(return_value)?;

    Ok(return_object)
  }

  pub async fn start_collecting(&mut self) -> Result<(), AnyError> {
    self.enable_debugger().await?;
    self.enable_profiler().await?;
    self
      .start_precise_coverage(cdp::StartPreciseCoverageArgs {
        call_count: true,
        detailed: true,
        allow_triggered_updates: false,
      })
      .await?;

    Ok(())
  }

  pub async fn stop_collecting(&mut self) -> Result<(), AnyError> {
    fs::create_dir_all(&self.dir)?;

    let script_coverages = self.take_precise_coverage().await?.result;
    for script_coverage in script_coverages {
      // Filter out internal JS files from being included in coverage reports
      if script_coverage.url.starts_with("ext:")
        || script_coverage.url.starts_with("[ext:")
      {
        continue;
      }

      let filename = format!("{}.json", Uuid::new_v4());
      let filepath = self.dir.join(filename);

      let mut out = BufWriter::new(File::create(&filepath)?);
      let coverage = serde_json::to_string(&script_coverage)?;
      let formatted_coverage =
        format_json(&filepath, &coverage, &Default::default())
          .ok()
          .flatten()
          .unwrap_or(coverage);

      out.write_all(formatted_coverage.as_bytes())?;
      out.flush()?;
    }

    self.disable_debugger().await?;
    self.disable_profiler().await?;

    Ok(())
  }
}

#[derive(Debug, Clone)]
struct BranchCoverageItem {
  line_index: usize,
  block_number: usize,
  branch_number: usize,
  taken: Option<i64>,
  is_hit: bool,
}

#[derive(Debug, Clone)]
struct FunctionCoverageItem {
  name: String,
  line_index: usize,
  execution_count: i64,
}

#[derive(Debug, Clone)]
struct CoverageReport {
  url: ModuleSpecifier,
  named_functions: Vec<FunctionCoverageItem>,
  branches: Vec<BranchCoverageItem>,
  /// (line_index, number_of_hits)
  found_lines: Vec<(usize, i64)>,
  output: Option<PathBuf>,
}

#[derive(Default)]
struct CoverageStats<'a> {
  pub line_hit: usize,
  pub line_miss: usize,
  pub branch_hit: usize,
  pub branch_miss: usize,
  pub parent: Option<String>,
  pub file_text: Option<String>,
  pub report: Option<&'a CoverageReport>,
}

type CoverageSummary<'a> = HashMap<String, CoverageStats<'a>>;

fn generate_coverage_report(
  script_coverage: &cdp::ScriptCoverage,
  script_source: String,
  maybe_source_map: &Option<Vec<u8>>,
  output: &Option<PathBuf>,
) -> CoverageReport {
  let maybe_source_map = maybe_source_map
    .as_ref()
    .map(|source_map| SourceMap::from_slice(source_map).unwrap());
  let text_lines = TextLines::new(&script_source);

  let comment_ranges = deno_ast::lex(&script_source, MediaType::JavaScript)
    .into_iter()
    .filter(|item| {
      matches!(item.inner, deno_ast::TokenOrComment::Comment { .. })
    })
    .map(|item| item.range)
    .collect::<Vec<_>>();

  let url = Url::parse(&script_coverage.url).unwrap();
  let mut coverage_report = CoverageReport {
    url,
    named_functions: Vec::with_capacity(
      script_coverage
        .functions
        .iter()
        .filter(|f| !f.function_name.is_empty())
        .count(),
    ),
    branches: Vec::new(),
    found_lines: Vec::new(),
    output: output.clone(),
  };

  for function in &script_coverage.functions {
    if function.function_name.is_empty() {
      continue;
    }

    let dest_line_index = text_lines.line_index(
      text_lines
        .byte_index_from_char_index(function.ranges[0].start_char_offset),
    );
    let line_index = if let Some(source_map) = maybe_source_map.as_ref() {
      source_map
        .tokens()
        .find(|token| token.get_dst_line() as usize == dest_line_index)
        .map(|token| token.get_src_line() as usize)
        .unwrap_or(0)
    } else {
      dest_line_index
    };

    coverage_report.named_functions.push(FunctionCoverageItem {
      name: function.function_name.clone(),
      line_index,
      execution_count: function.ranges[0].count,
    });
  }

  for (block_number, function) in script_coverage.functions.iter().enumerate() {
    let block_hits = function.ranges[0].count;
    for (branch_number, range) in function.ranges[1..].iter().enumerate() {
      let source_line_index = text_lines.line_index(
        text_lines.byte_index_from_char_index(range.start_char_offset),
      );
      let line_index = if let Some(source_map) = maybe_source_map.as_ref() {
        source_map
          .tokens()
          .find(|token| token.get_dst_line() as usize == source_line_index)
          .map(|token| token.get_src_line() as usize)
          .unwrap_or(0)
      } else {
        source_line_index
      };

      // From https://manpages.debian.org/unstable/lcov/geninfo.1.en.html:
      //
      // Block number and branch number are gcc internal IDs for the branch. Taken is either '-'
      // if the basic block containing the branch was never executed or a number indicating how
      // often that branch was taken.
      //
      // However with the data we get from v8 coverage profiles it seems we can't actually hit
      // this as appears it won't consider any nested branches it hasn't seen but its here for
      // the sake of accuracy.
      let taken = if block_hits > 0 {
        Some(range.count)
      } else {
        None
      };

      coverage_report.branches.push(BranchCoverageItem {
        line_index,
        block_number,
        branch_number,
        taken,
        is_hit: range.count > 0,
      })
    }
  }

  // TODO(caspervonb): collect uncovered ranges on the lines so that we can highlight specific
  // parts of a line in color (word diff style) instead of the entire line.
  let mut line_counts = Vec::with_capacity(text_lines.lines_count());
  for line_index in 0..text_lines.lines_count() {
    let line_start_byte_offset = text_lines.line_start(line_index);
    let line_start_char_offset = text_lines.char_index(line_start_byte_offset);
    let line_end_byte_offset = text_lines.line_end(line_index);
    let line_end_char_offset = text_lines.char_index(line_end_byte_offset);
    let ignore = comment_ranges.iter().any(|range| {
      range.start <= line_start_byte_offset && range.end >= line_end_byte_offset
    }) || script_source
      [line_start_byte_offset..line_end_byte_offset]
      .trim()
      .is_empty();
    let mut count = 0;

    if ignore {
      count = 1;
    } else {
      // Count the hits of ranges that include the entire line which will always be at-least one
      // as long as the code has been evaluated.
      for function in &script_coverage.functions {
        for range in &function.ranges {
          if range.start_char_offset <= line_start_char_offset
            && range.end_char_offset >= line_end_char_offset
          {
            count += range.count;
          }
        }
      }

      // We reset the count if any block with a zero count overlaps with the line range.
      for function in &script_coverage.functions {
        for range in &function.ranges {
          if range.count > 0 {
            continue;
          }

          let overlaps = range.start_char_offset < line_end_char_offset
            && range.end_char_offset > line_start_char_offset;
          if overlaps {
            count = 0;
          }
        }
      }
    }

    line_counts.push(count);
  }

  coverage_report.found_lines =
    if let Some(source_map) = maybe_source_map.as_ref() {
      let mut found_lines = line_counts
        .iter()
        .enumerate()
        .flat_map(|(index, count)| {
          // get all the mappings from this destination line to a different src line
          let mut results = source_map
            .tokens()
            .filter(move |token| token.get_dst_line() as usize == index)
            .map(move |token| (token.get_src_line() as usize, *count))
            .collect::<Vec<_>>();
          // only keep the results that point at different src lines
          results.sort_unstable_by_key(|(index, _)| *index);
          results.dedup_by_key(|(index, _)| *index);
          results.into_iter()
        })
        .collect::<Vec<(usize, i64)>>();

      found_lines.sort_unstable_by_key(|(index, _)| *index);
      // combine duplicated lines
      for i in (1..found_lines.len()).rev() {
        if found_lines[i].0 == found_lines[i - 1].0 {
          found_lines[i - 1].1 += found_lines[i].1;
          found_lines.remove(i);
        }
      }
      found_lines
    } else {
      line_counts
        .into_iter()
        .enumerate()
        .map(|(index, count)| (index, count))
        .collect::<Vec<(usize, i64)>>()
    };

  coverage_report
}

enum CoverageReporterKind {
  Pretty,
  Lcov,
  Html,
}

fn create_reporter(
  kind: CoverageReporterKind,
) -> Box<dyn CoverageReporter + Send> {
  match kind {
    CoverageReporterKind::Lcov => Box::new(LcovCoverageReporter::new()),
    CoverageReporterKind::Pretty => Box::new(PrettyCoverageReporter::new()),
    CoverageReporterKind::Html => Box::new(HtmlCoverageReporter::new()),
  }
}

trait CoverageReporter {
  fn report(
    &mut self,
    coverage_report: &CoverageReport,
    file_text: &str,
  ) -> Result<(), AnyError>;

  fn done(&mut self, _coverage_root: &Path) {}
}

struct LcovCoverageReporter {}

impl LcovCoverageReporter {
  pub fn new() -> LcovCoverageReporter {
    LcovCoverageReporter {}
  }
}

impl CoverageReporter for LcovCoverageReporter {
  fn report(
    &mut self,
    coverage_report: &CoverageReport,
    _file_text: &str,
  ) -> Result<(), AnyError> {
    // pipes output to stdout if no file is specified
    let out_mode: Result<Box<dyn Write>, Error> = match coverage_report.output {
      // only append to the file as the file should be created already
      Some(ref path) => File::options()
        .append(true)
        .open(path)
        .map(|f| Box::new(f) as Box<dyn Write>),
      None => Ok(Box::new(io::stdout())),
    };
    let mut out_writer = out_mode?;

    let file_path = coverage_report
      .url
      .to_file_path()
      .ok()
      .and_then(|p| p.to_str().map(|p| p.to_string()))
      .unwrap_or_else(|| coverage_report.url.to_string());
    writeln!(out_writer, "SF:{file_path}")?;

    for function in &coverage_report.named_functions {
      writeln!(
        out_writer,
        "FN:{},{}",
        function.line_index + 1,
        function.name
      )?;
    }

    for function in &coverage_report.named_functions {
      writeln!(
        out_writer,
        "FNDA:{},{}",
        function.execution_count, function.name
      )?;
    }

    let functions_found = coverage_report.named_functions.len();
    writeln!(out_writer, "FNF:{functions_found}")?;
    let functions_hit = coverage_report
      .named_functions
      .iter()
      .filter(|f| f.execution_count > 0)
      .count();
    writeln!(out_writer, "FNH:{functions_hit}")?;

    for branch in &coverage_report.branches {
      let taken = if let Some(taken) = &branch.taken {
        taken.to_string()
      } else {
        "-".to_string()
      };

      writeln!(
        out_writer,
        "BRDA:{},{},{},{}",
        branch.line_index + 1,
        branch.block_number,
        branch.branch_number,
        taken
      )?;
    }

    let branches_found = coverage_report.branches.len();
    writeln!(out_writer, "BRF:{branches_found}")?;
    let branches_hit =
      coverage_report.branches.iter().filter(|b| b.is_hit).count();
    writeln!(out_writer, "BRH:{branches_hit}")?;
    for (index, count) in &coverage_report.found_lines {
      writeln!(out_writer, "DA:{},{}", index + 1, count)?;
    }

    let lines_hit = coverage_report
      .found_lines
      .iter()
      .filter(|(_, count)| *count != 0)
      .count();
    writeln!(out_writer, "LH:{lines_hit}")?;

    let lines_found = coverage_report.found_lines.len();
    writeln!(out_writer, "LF:{lines_found}")?;

    writeln!(out_writer, "end_of_record")?;
    Ok(())
  }
}

struct PrettyCoverageReporter {}

impl PrettyCoverageReporter {
  pub fn new() -> PrettyCoverageReporter {
    PrettyCoverageReporter {}
  }
}

impl CoverageReporter for PrettyCoverageReporter {
  fn report(
    &mut self,
    coverage_report: &CoverageReport,
    file_text: &str,
  ) -> Result<(), AnyError> {
    let lines = file_text.split('\n').collect::<Vec<_>>();
    print!("cover {} ... ", coverage_report.url);

    let hit_lines = coverage_report
      .found_lines
      .iter()
      .filter(|(_, count)| *count > 0)
      .map(|(index, _)| *index);

    let missed_lines = coverage_report
      .found_lines
      .iter()
      .filter(|(_, count)| *count == 0)
      .map(|(index, _)| *index);

    let lines_found = coverage_report.found_lines.len();
    let lines_hit = hit_lines.count();
    let line_ratio = lines_hit as f32 / lines_found as f32;

    let line_coverage =
      format!("{:.3}% ({}/{})", line_ratio * 100.0, lines_hit, lines_found);

    if line_ratio >= 0.9 {
      println!("{}", colors::green(&line_coverage));
    } else if line_ratio >= 0.75 {
      println!("{}", colors::yellow(&line_coverage));
    } else {
      println!("{}", colors::red(&line_coverage));
    }

    let mut last_line = None;
    for line_index in missed_lines {
      const WIDTH: usize = 4;
      const SEPARATOR: &str = "|";

      // Put a horizontal separator between disjoint runs of lines
      if let Some(last_line) = last_line {
        if last_line + 1 != line_index {
          let dash = colors::gray("-".repeat(WIDTH + 1));
          println!("{}{}{}", dash, colors::gray(SEPARATOR), dash);
        }
      }

      println!(
        "{:width$} {} {}",
        line_index + 1,
        colors::gray(SEPARATOR),
        colors::red(&lines[line_index]),
        width = WIDTH
      );

      last_line = Some(line_index);
    }
    Ok(())
  }
}

struct HtmlCoverageReporter {
  file_reports: Vec<(CoverageReport, String)>,
}

impl HtmlCoverageReporter {
  pub fn new() -> HtmlCoverageReporter {
    HtmlCoverageReporter {
      file_reports: Vec::new(),
    }
  }
}

impl CoverageReporter for HtmlCoverageReporter {
  fn report(
    &mut self,
    report: &CoverageReport,
    text: &str,
  ) -> Result<(), AnyError> {
    self.file_reports.push((report.clone(), text.to_string()));
    Ok(())
  }

  fn done(&mut self, coverage_root: &Path) {
    let summary = self.collect_summary();
    let now = crate::util::time::utc_now().to_rfc2822();

    for (node, stats) in &summary {
      let report_path =
        self.get_report_path(coverage_root, node, stats.file_text.is_none());
      let main_content = if let Some(file_text) = &stats.file_text {
        self.create_html_code_table(file_text, stats.report.unwrap())
      } else {
        self.create_html_summary_table(node, &summary)
      };
      let is_dir = stats.file_text.is_none();
      let html = self.create_html(node, is_dir, stats, &now, &main_content);
      fs::create_dir_all(report_path.parent().unwrap()).unwrap();
      fs::write(report_path, html).unwrap();
    }

    let root_report = Url::from_file_path(
      coverage_root
        .join("html")
        .join("index.html")
        .canonicalize()
        .unwrap(),
    )
    .unwrap();

    println!("HTML coverage report has been generated at {}", root_report);
  }
}

impl HtmlCoverageReporter {
  /// Collects the coverage summary of each file or directory.
  pub fn collect_summary(&self) -> CoverageSummary {
    let urls = self.file_reports.iter().map(|rep| &rep.0.url).collect();
    let root = util::find_root(urls).unwrap().to_file_path().unwrap();
    // summary by file or directory
    // tuple of (line hit, line miss, branch hit, branch miss, parent)
    let mut summary = HashMap::new();
    summary.insert("".to_string(), CoverageStats::default()); // root entry
    for (report, file_text) in &self.file_reports {
      let path = report.url.to_file_path().unwrap();
      let relative_path = path.strip_prefix(&root).unwrap();
      let mut file_text = Some(file_text.to_string());

      let mut summary_path = Some(relative_path);
      // From leaf to root, adds up the coverage stats
      while let Some(path) = summary_path {
        let path_str = path.to_str().unwrap().to_string();
        let parent = path
          .parent()
          .and_then(|p| p.to_str())
          .map(|p| p.to_string());
        let stats = summary.entry(path_str).or_insert(CoverageStats {
          parent,
          file_text,
          report: Some(report),
          ..CoverageStats::default()
        });

        stats.line_hit += report
          .found_lines
          .iter()
          .filter(|(_, count)| *count > 0)
          .count();
        stats.line_miss += report
          .found_lines
          .iter()
          .filter(|(_, count)| *count == 0)
          .count();
        stats.branch_hit += report.branches.iter().filter(|b| b.is_hit).count();
        stats.branch_miss +=
          report.branches.iter().filter(|b| !b.is_hit).count();

        file_text = None;
        summary_path = path.parent();
      }
    }

    summary
  }

  /// Gets the report path for a single file
  pub fn get_report_path(
    &self,
    coverage_root: &Path,
    node: &str,
    is_dir: bool,
  ) -> PathBuf {
    if is_dir {
      // e.g. /path/to/coverage/html/src/index.html
      coverage_root.join("html").join(node).join("index.html")
    } else {
      // e.g. /path/to/coverage/html/src/main.ts.html
      Path::new(&format!(
        "{}.html",
        coverage_root.join("html").join(node).to_str().unwrap()
      ))
      .to_path_buf()
    }
  }

  /// Creates single page of html report.
  pub fn create_html(
    &self,
    node: &str,
    is_dir: bool,
    stats: &CoverageStats,
    timestamp: &str,
    main_content: &str,
  ) -> String {
    let title = if node.is_empty() {
      "Coverage report for all files".to_string()
    } else {
      let node = if is_dir {
        format!("{}/", node)
      } else {
        node.to_string()
      };
      format!("Coverage report for {node}")
    };
    let title = title.replace(std::path::MAIN_SEPARATOR, "/");
    let head = self.create_html_head(&title);
    let header = self.create_html_header(&title, stats);
    let footer = self.create_html_footer(timestamp);
    format!(
      "<!doctype html>
      <html>
        {head}
        <body>
          <div class='wrapper'>
            {header}
            <div class='pad1'>
              {main_content}
            </div>
            <div class='push'></div>
          </div>
          {footer}
        </body>
      </html>"
    )
  }

  /// Creates <head> tag for html report.
  pub fn create_html_head(&self, title: &str) -> String {
    let style_css = include_str!("style.css");
    format!(
      "
      <head>
        <meta charset='utf-8'>
        <title>{title}</title>
        <style>{style_css}</style>
        <meta name='viewport' content='width=device-width, initial-scale=1' />
      </head>"
    )
  }

  /// Creates header part of the contents for html report.
  pub fn create_html_header(
    &self,
    title: &str,
    stats: &CoverageStats,
  ) -> String {
    let CoverageStats {
      line_hit,
      line_miss,
      branch_hit,
      branch_miss,
      ..
    } = stats;
    let (line_total, line_percent, line_class) =
      util::calc_coverage_display_info(*line_hit, *line_miss);
    let (branch_total, branch_percent, _) =
      util::calc_coverage_display_info(*branch_hit, *branch_miss);

    format!(
      "
      <div class='pad1'>
        <h1>{title}</h1>
        <div class='clearfix'>
          <div class='fl pad1y space-right2'>
            <span class='strong'>{branch_percent:.2}%</span>
            <span class='quiet'>Branches</span>
            <span class='fraction'>{branch_hit}/{branch_total}</span>
          </div>
          <div class='fl pad1y space-right2'>
            <span class='strong'>{line_percent:.2}%</span>
            <span class='quiet'>Lines</span>
            <span class='fraction'>{line_hit}/{line_total}</span>
          </div>
        </div>
      </div>
      <div class='status-line {line_class}'></div>"
    )
  }

  /// Creates footer part of the contents for html report.
  pub fn create_html_footer(&self, now: &str) -> String {
    let version = env!("CARGO_PKG_VERSION");
    format!(
      "
      <div class='footer quiet pad2 space-top1 center small'>
        Code coverage generated by
        <a href='https://deno.com/' target='_blank'>Deno v{version}</a>
        at {now}
      </div>"
    )
  }

  /// Creates <table> of summary for html report.
  pub fn create_html_summary_table(
    &self,
    node: &String,
    summary: &CoverageSummary,
  ) -> String {
    let mut children = summary
      .iter()
      .filter(|(_, stats)| stats.parent.as_ref() == Some(node))
      .map(|(k, stats)| (stats.file_text.is_some(), k.clone()))
      .collect::<Vec<_>>();
    // Sort directories first, then files
    children.sort();

    let table_rows: Vec<String> = children.iter().map(|(is_file, c)| {
    let CoverageStats { line_hit, line_miss, branch_hit, branch_miss, .. } =
      summary.get(c).unwrap();

    let (line_total, line_percent, line_class) =
      util::calc_coverage_display_info(*line_hit, *line_miss);
    let (branch_total, branch_percent, branch_class) =
      util::calc_coverage_display_info(*branch_hit, *branch_miss);

    let path = Path::new(c.strip_prefix(&format!("{node}{}", std::path::MAIN_SEPARATOR)).unwrap_or(c)).to_str().unwrap();
    let path = path.replace(std::path::MAIN_SEPARATOR, "/");
    let path_label = if *is_file { path.to_string() } else { format!("{}/", path) };
    let path_link = if *is_file { format!("{}.html", path) } else { format!("{}index.html", path_label) };

    format!("
      <tr>
        <td class='file {line_class}'><a href='{path_link}'>{path_label}</a></td>
        <td class='pic {line_class}'>
          <div class='chart'>
            <div class='cover-fill' style='width: {line_percent:.1}%'></div><div class='cover-empty' style='width: calc(100% - {line_percent:.1}%)'></div>
          </div>
        </td>
        <td class='pct {branch_class}'>{branch_percent:.2}%</td>
        <td class='abs {branch_class}'>{branch_hit}/{branch_total}</td>
        <td class='pct {line_class}'>{line_percent:.2}%</td>
        <td class='abs {line_class}'>{line_hit}/{line_total}</td>
      </tr>")}).collect();
    let table_rows = table_rows.join("\n");

    format!(
      "
      <table class='coverage-summary'>
        <thead>
          <tr>
            <th class='file'>File</th>
            <th class='pic'></th>
            <th class='pct'>Branches</th>
            <th class='abs'></th>
            <th class='pct'>Lines</th>
            <th class='abs'></th>
          </tr>
        </thead>
        <tbody>
          {table_rows}
        </tbody>
      </table>"
    )
  }

  /// Creates <table> of single file code coverage.
  pub fn create_html_code_table(
    &self,
    file_text: &String,
    report: &CoverageReport,
  ) -> String {
    let line_num = file_text.lines().count();
    let line_count = (1..line_num + 1)
      .map(|i| format!("<a name='L{i}'></a><a href='#{i}'>{i}</a>"))
      .collect::<Vec<_>>()
      .join("\n");
    let line_coverage = (0..line_num)
      .map(|i| {
        if let Some((_, count)) =
          report.found_lines.iter().find(|(line, _)| i == *line)
        {
          if *count == 0 {
            "<span class='cline-any cline-no'>&nbsp</span>".to_string()
          } else {
            format!("<span class='cline-any cline-yes'>x{count}</span>")
          }
        } else {
          "<span class='cline-any cline-neutral'>&nbsp</span>".to_string()
        }
      })
      .collect::<Vec<_>>()
      .join("\n");
    let branch_coverage = (0..line_num)
      .map(|i| {
        let branch_is_missed = report.branches.iter().any(|b| b.line_index == i && !b.is_hit);
        if branch_is_missed {
          "<span class='missing-if-branch' title='branch condition is missed in this line'>I</span>".to_string()
        } else {
          "".to_string()
        }
      })
      .collect::<Vec<_>>()
      .join("\n");

    // TODO(kt3k): Add syntax highlight to source code
    format!(
      "<table class='coverage'>
        <tr>
          <td class='line-count quiet'><pre>{line_count}</pre></td>
          <td class='line-coverage quiet'><pre>{line_coverage}</pre></td>
          <td class='branch-coverage quiet'><pre>{branch_coverage}</pre></td>
          <td class='text'><pre class='prettyprint'>{file_text}</pre></td>
        </tr>
      </table>"
    )
  }
}

fn collect_coverages(
  files: FileFlags,
) -> Result<Vec<cdp::ScriptCoverage>, AnyError> {
  let mut coverages: Vec<cdp::ScriptCoverage> = Vec::new();
  let file_paths = FileCollector::new(|file_path| {
    file_path
      .extension()
      .map(|ext| ext == "json")
      .unwrap_or(false)
  })
  .ignore_git_folder()
  .ignore_node_modules()
  .ignore_vendor_folder()
  .add_ignore_paths(&files.ignore)
  .collect_files(if files.include.is_empty() {
    None
  } else {
    Some(&files.include)
  })?;

  for file_path in file_paths {
    let json = fs::read_to_string(file_path.as_path())?;
    let new_coverage: cdp::ScriptCoverage = serde_json::from_str(&json)?;
    coverages.push(new_coverage);
  }

  coverages.sort_by_key(|k| k.url.clone());

  Ok(coverages)
}

fn filter_coverages(
  coverages: Vec<cdp::ScriptCoverage>,
  include: Vec<String>,
  exclude: Vec<String>,
  npm_resolver: &dyn CliNpmResolver,
) -> Vec<cdp::ScriptCoverage> {
  let include: Vec<Regex> =
    include.iter().map(|e| Regex::new(e).unwrap()).collect();

  let exclude: Vec<Regex> =
    exclude.iter().map(|e| Regex::new(e).unwrap()).collect();

  coverages
    .into_iter()
    .filter(|e| {
      let is_internal = e.url.starts_with("ext:")
        || e.url.ends_with("__anonymous__")
        || e.url.ends_with("$deno$test.js")
        || e.url.ends_with(".snap")
        || is_supported_test_path(Path::new(e.url.as_str()))
        || Url::parse(&e.url)
          .ok()
          .map(|url| npm_resolver.in_npm_package(&url))
          .unwrap_or(false);

      let is_included = include.iter().any(|p| p.is_match(&e.url));
      let is_excluded = exclude.iter().any(|p| p.is_match(&e.url));

      (include.is_empty() || is_included) && !is_excluded && !is_internal
    })
    .collect::<Vec<cdp::ScriptCoverage>>()
}

pub async fn cover_files(
  flags: Flags,
  coverage_flags: CoverageFlags,
) -> Result<(), AnyError> {
  if coverage_flags.files.include.is_empty() {
    return Err(generic_error("No matching coverage profiles found"));
  }

  let factory = CliFactory::from_flags(flags).await?;
  let npm_resolver = factory.npm_resolver().await?;
  let file_fetcher = factory.file_fetcher()?;
  let cli_options = factory.cli_options();
  let emitter = factory.emitter()?;

  assert!(!coverage_flags.files.include.is_empty());

  // Use the first include path as the default output path.
  let coverage_root = coverage_flags.files.include[0].clone();

  let script_coverages = collect_coverages(coverage_flags.files)?;
  let script_coverages = filter_coverages(
    script_coverages,
    coverage_flags.include,
    coverage_flags.exclude,
    npm_resolver.as_ref(),
  );

  let proc_coverages: Vec<_> = script_coverages
    .into_iter()
    .map(|cov| ProcessCoverage { result: vec![cov] })
    .collect();

  let script_coverages = if let Some(c) = merge::merge_processes(proc_coverages)
  {
    c.result
  } else {
    vec![]
  };

  let reporter_kind = match coverage_flags.r#type {
    CoverageType::Pretty => CoverageReporterKind::Pretty,
    CoverageType::Lcov => CoverageReporterKind::Lcov,
    CoverageType::Html => CoverageReporterKind::Html,
  };

  let mut reporter = create_reporter(reporter_kind);

  let out_mode = match coverage_flags.output {
    Some(ref path) => match File::create(path) {
      Ok(_) => Some(PathBuf::from(path)),
      Err(e) => {
        return Err(anyhow!("Failed to create output file: {}", e));
      }
    },
    None => None,
  };

  for script_coverage in script_coverages {
    let module_specifier = deno_core::resolve_url_or_path(
      &script_coverage.url,
      cli_options.initial_cwd(),
    )?;

    let maybe_file = if module_specifier.scheme() == "file" {
      file_fetcher.get_source(&module_specifier)
    } else {
      file_fetcher
        .fetch_cached(&module_specifier, 10)
        .with_context(|| {
          format!("Failed to fetch \"{module_specifier}\" from cache.")
        })?
    };
    let file = maybe_file.ok_or_else(|| {
      anyhow!("Failed to fetch \"{}\" from cache.
          Before generating coverage report, run `deno test --coverage` to ensure consistent state.",
          module_specifier
        )
    })?;

    // Check if file was transpiled
    let original_source = file.source.clone();
    let transpiled_code: ModuleCode = match file.media_type {
      MediaType::JavaScript
      | MediaType::Unknown
      | MediaType::Cjs
      | MediaType::Mjs
      | MediaType::Json => file.source.clone().into(),
      MediaType::Dts | MediaType::Dmts | MediaType::Dcts => Default::default(),
      MediaType::TypeScript
      | MediaType::Jsx
      | MediaType::Mts
      | MediaType::Cts
      | MediaType::Tsx => {
        match emitter.maybe_cached_emit(&file.specifier, &file.source) {
          Some(code) => code.into(),
          None => {
            return Err(anyhow!(
              "Missing transpiled source code for: \"{}\".
              Before generating coverage report, run `deno test --coverage` to ensure consistent state.",
              file.specifier,
            ))
          }
        }
      }
      MediaType::Wasm | MediaType::TsBuildInfo | MediaType::SourceMap => {
        unreachable!()
      }
    };

    let source_map = source_map_from_code(&transpiled_code);
    let coverage_report = generate_coverage_report(
      &script_coverage,
      transpiled_code.as_str().to_owned(),
      &source_map,
      &out_mode,
    );

    if !coverage_report.found_lines.is_empty() {
      reporter.report(&coverage_report, &original_source)?;
    }
  }

  reporter.done(&coverage_root);

  Ok(())
}