process: refactor coverage setup during bootstrap

- Renamed `internal/process/write-coverage.js` to
  `internal/coverage-gen/with_instrumentation.js`,
  `internal/process/coverage.js` to
  `internal/coverage-gen/with_profiler.js` to distinguish
  the two better and added comments.
- Separate the coverage directory setup and the connection
  setup, moves the directory setup into `node.js` and
  closer to the exit hooks because that's where it's used.
- Moves the `process.reallyExit` overwrite and
  `process.on('exit')` hooks setup into bootstrap/node.js
  for clarity, and move them to a later stage of
  bootstrap since they do not have to happen that early.

PR-URL: https://github.com/nodejs/node/pull/25398
Reviewed-By: Ben Coe <bencoe@gmail.com>

1 files changed, 36 insertions, 0 deletions

diff --git a/lib/internal/coverage-gen/with_instrumentation.js b/lib/internal/coverage-gen/with_instrumentation.js
new file mode 100644
index 0000000000..711a3c3f12
--- /dev/null
+++ b/lib/internal/coverage-gen/with_instrumentation.js
@@ -0,0 +1,36 @@
+'use strict';
+
+// This file contains hooks for nyc instrumented lib/ files to collect
+// JS coverage for core.
+// See `make coverage-build`.
+function writeCoverage() {
+  if (!global.__coverage__) {
+    return;
+  }
+
+  const path = require('path');
+  const { mkdirSync, writeFileSync } = require('fs');
+
+  const dirname = path.join(path.dirname(process.execPath), '.coverage');
+  const filename = `coverage-${process.pid}-${Date.now()}.json`;
+  try {
+    mkdirSync(dirname);
+  } catch (err) {
+    if (err.code !== 'EEXIST') {
+      console.error(err);
+      return;
+    }
+  }
+
+  const target = path.join(dirname, filename);
+  const coverageInfo = JSON.stringify(global.__coverage__);
+  try {
+    writeFileSync(target, coverageInfo);
+  } catch (err) {
+    console.error(err);
+  }
+}
+
+module.exports = {
+  writeCoverage
+};