1 files changed, 87 insertions, 0 deletions
diff --git a/dom/media/eme/DetailedPromise.cpp b/dom/media/eme/DetailedPromise.cpp
new file mode 100644
index 0000000000..0692a1dd07
--- /dev/null
+++ b/dom/media/eme/DetailedPromise.cpp
@@ -0,0 +1,87 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=2 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "DetailedPromise.h"
+
+#include "VideoUtils.h"
+#include "mozilla/dom/DOMException.h"
+#include "nsPrintfCString.h"
+
+namespace mozilla::dom {
+
+DetailedPromise::DetailedPromise(nsIGlobalObject* aGlobal,
+                                 const nsACString& aName)
+    : Promise(aGlobal),
+      mName(aName),
+      mResponded(false),
+      mStartTime(TimeStamp::Now()) {}
+
+DetailedPromise::DetailedPromise(nsIGlobalObject* aGlobal,
+                                 const nsACString& aName,
+                                 Telemetry::HistogramID aSuccessLatencyProbe,
+                                 Telemetry::HistogramID aFailureLatencyProbe)
+    : DetailedPromise(aGlobal, aName) {
+  mSuccessLatencyProbe.Construct(aSuccessLatencyProbe);
+  mFailureLatencyProbe.Construct(aFailureLatencyProbe);
+}
+
+DetailedPromise::~DetailedPromise() {
+  // It would be nice to assert that mResponded is identical to
+  // GetPromiseState() == PromiseState::Rejected.  But by now we've been
+  // unlinked, so don't have a reference to our actual JS Promise object
+  // anymore.
+  MaybeReportTelemetry(kFailed);
+}
+
+void DetailedPromise::LogRejectionReason(uint32_t aErrorCode,
+                                         const nsACString& aReason) {
+  nsPrintfCString msg("%s promise rejected 0x%" PRIx32 " '%s'", mName.get(),
+                      aErrorCode, PromiseFlatCString(aReason).get());
+  EME_LOG("%s", msg.get());
+
+  MaybeReportTelemetry(kFailed);
+
+  LogToBrowserConsole(NS_ConvertUTF8toUTF16(msg));
+}
+
+void DetailedPromise::MaybeReject(nsresult aArg, const nsACString& aReason) {
+  LogRejectionReason(static_cast<uint32_t>(aArg), aReason);
+
+  Promise::MaybeRejectWithDOMException(aArg, aReason);
+}
+
+void DetailedPromise::MaybeReject(ErrorResult&& aArg,
+                                  const nsACString& aReason) {
+  LogRejectionReason(aArg.ErrorCodeAsInt(), aReason);
+  Promise::MaybeReject(std::move(aArg));
+}
+
+/* static */
+already_AddRefed<DetailedPromise> DetailedPromise::Create(
+    nsIGlobalObject* aGlobal, ErrorResult& aRv, const nsACString& aName) {
+  RefPtr<DetailedPromise> promise = new DetailedPromise(aGlobal, aName);
+  promise->CreateWrapper(aRv);
+  return aRv.Failed() ? nullptr : promise.forget();
+}
+
+void DetailedPromise::MaybeReportTelemetry(eStatus aStatus) {
+  if (mResponded) {
+    return;
+  }
+  mResponded = true;
+  if (!mSuccessLatencyProbe.WasPassed() || !mFailureLatencyProbe.WasPassed()) {
+    return;
+  }
+  uint32_t latency = (TimeStamp::Now() - mStartTime).ToMilliseconds();
+  EME_LOG("%s %s latency %ums reported via telemetry", mName.get(),
+          ((aStatus == kSucceeded) ? "succcess" : "failure"), latency);
+  Telemetry::HistogramID tid = (aStatus == kSucceeded)
+                                   ? mSuccessLatencyProbe.Value()
+                                   : mFailureLatencyProbe.Value();
+  Telemetry::Accumulate(tid, latency);
+}
+
+}  // namespace mozilla::dom