1934531 - Refactor BounceTrackingProtection logging to use FMT

Status: NEW

(Core :: Privacy: Anti-Tracking, task, P3)

Description

[Emma Zühlcke [:emz]]

Now that we have MOZ_LOG_FMT we can make logging much nicer.
https://firefox-source-docs.mozilla.org/xpcom/fmt-in-gecko.html

We should replace our MOZ_LOG uses in BTP with MOZ_LOG_FMT and also make use of custom formatters so we'll no longer need Describe methods like here: https://searchfox.org/mozilla-central/rev/6597dd03bad82c891d084eed25cafd0c85fb333e/toolkit/components/antitracking/bouncetrackingprotection/BounceTrackingRecord.cpp#75

Comment 1

[Emma Zühlcke [:emz]]

For logging the service mode field I tried something like this:

namespace fmt {

template <>
struct formatter<::nsIBounceTrackingProtection::Modes> {
  constexpr auto parse(format_parse_context& ctx) {
    return ctx.begin();
  }

  template <typename FormatContext>
  auto format(const ::nsIBounceTrackingProtection::Modes& mode, FormatContext& ctx) const {
    switch (mode) {
      case ::nsIBounceTrackingProtection::MODE_DISABLED:
        return format_to(ctx.out(), FMT_STRING("MODE_DISABLED"));
      case ::nsIBounceTrackingProtection::MODE_ENABLED:
        return format_to(ctx.out(), FMT_STRING("MODE_ENABLED"));
      case ::nsIBounceTrackingProtection::MODE_ENABLED_STANDBY:
        return format_to(ctx.out(), FMT_STRING("MODE_ENABLED_STANDBY"));
      case ::nsIBounceTrackingProtection::MODE_ENABLED_DRY_RUN:
        return format_to(ctx.out(), FMT_STRING("MODE_ENABLED_DRY_RUN"));
      default:
        return format_to(ctx.out(), FMT_STRING("UNKNOWN_MODE"));
    }
  }
};

}  // namespace fmt

though there might be more concise ways to do this. Normally you'd define the formatter as part of the class, but I couldn't get that to work for an xpcom generated type.