feat(inspector): serve source maps to DevTools via Network.loadNetwor… by edusperoni · Pull Request #1969 · NativeScript/android

…kResource

Chrome DevTools no longer fetches external source maps itself when
debugging remote targets: it issues Network.loadNetworkResource to the
target and reads the result back through IO.read/IO.close. None of these
embedder-side CDP domains are implemented by V8's inspector, so external
source maps failed and apps had to fall back to bloated
inline-source-map builds.

- Handle Network.loadNetworkResource natively: resolve the URL back to a
  file on disk and reply with a stream handle (success:false +
  net::ERR_FILE_NOT_FOUND when missing).
- Implement IO.read (1MB base64 chunks; eof only on a final empty read,
  since the frontend discards data accompanying eof) and IO.close.
- Reply with a JSON-RPC error for unsupported schemes (e.g. https) so
  DevTools keeps its existing fallback of fetching from the host.
- Rewrite sourceMapURL in outgoing Debugger.scriptParsed /
  Debugger.scriptFailedToParse events from relative/file:// URLs to a
  custom nsruntime:// scheme. DevTools hard-excludes file:, data: and
  devtools: URLs from loading through the target, so without the rewrite
  it would never send Network.loadNetworkResource and instead try (and
  fail) to read device files from the host machine. data: and http(s)
  URLs are left untouched, keeping inline source maps working.
- Allow opting out via nativescript.config.ts:
  android.disableSourceMapURLRewrite (or the same key at the top level).
- Serve these messages on the websocket read thread (new native
  handleMessageOnSocketThread), since the main-thread queue is
  unavailable exactly when DevTools needs source maps: the pause loop
  bypasses dispatchMessage and a busy isolate never drains the queue.
  The handler is V8-free and returns the response for Java to send on
  the receiving socket.
- Make Debugger.pause interrupt busy JS via Isolate::RequestInterrupt,
  skipped while already paused in the nested loop to avoid a spurious
  re-pause after resume.
- Vendor nlohmann/json v3.12.0 (third_party/json.hpp, header-only) for
  CDP message handling outside V8.

Ports NativeScript/ios#385 and NativeScript/ios#378 to Android.

Refs: nodejs/node#58077