1 files changed, 106 insertions, 0 deletions
diff --git a/toolkit/components/glean/bindings/private/MemoryDistribution.cpp b/toolkit/components/glean/bindings/private/MemoryDistribution.cpp
new file mode 100644
index 0000000000..f21cbd3880
--- /dev/null
+++ b/toolkit/components/glean/bindings/private/MemoryDistribution.cpp
@@ -0,0 +1,106 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 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 "mozilla/glean/bindings/MemoryDistribution.h"
+
+#include "mozilla/Components.h"
+#include "mozilla/Maybe.h"
+#include "mozilla/ResultVariant.h"
+#include "mozilla/glean/bindings/HistogramGIFFTMap.h"
+#include "mozilla/glean/fog_ffi_generated.h"
+#include "nsIClassInfoImpl.h"
+#include "nsJSUtils.h"
+#include "nsPrintfCString.h"
+#include "nsString.h"
+#include "js/PropertyAndElement.h"  // JS_DefineProperty
+
+namespace mozilla::glean {
+
+namespace impl {
+
+void MemoryDistributionMetric::Accumulate(size_t aSample) const {
+  auto hgramId = HistogramIdForMetric(mId);
+  if (hgramId) {
+    Telemetry::Accumulate(hgramId.extract(), aSample);
+  }
+  static_assert(sizeof(size_t) <= sizeof(uint64_t),
+                "Memory distribution samples might overflow.");
+  fog_memory_distribution_accumulate(mId, aSample);
+}
+
+Result<Maybe<DistributionData>, nsCString>
+MemoryDistributionMetric::TestGetValue(const nsACString& aPingName) const {
+  nsCString err;
+  if (fog_memory_distribution_test_get_error(mId, &err)) {
+    return Err(err);
+  }
+  if (!fog_memory_distribution_test_has_value(mId, &aPingName)) {
+    return Maybe<DistributionData>();
+  }
+  nsTArray<uint64_t> buckets;
+  nsTArray<uint64_t> counts;
+  uint64_t sum;
+  fog_memory_distribution_test_get_value(mId, &aPingName, &sum, &buckets,
+                                         &counts);
+  return Some(DistributionData(buckets, counts, sum));
+}
+
+}  // namespace impl
+
+NS_IMPL_CLASSINFO(GleanMemoryDistribution, nullptr, 0, {0})
+NS_IMPL_ISUPPORTS_CI(GleanMemoryDistribution, nsIGleanMemoryDistribution)
+
+NS_IMETHODIMP
+GleanMemoryDistribution::Accumulate(uint64_t aSample) {
+  mMemoryDist.Accumulate(aSample);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+GleanMemoryDistribution::TestGetValue(const nsACString& aPingName,
+                                      JSContext* aCx,
+                                      JS::MutableHandle<JS::Value> aResult) {
+  auto result = mMemoryDist.TestGetValue(aPingName);
+  if (result.isErr()) {
+    aResult.set(JS::UndefinedValue());
+    return NS_ERROR_LOSS_OF_SIGNIFICANT_DATA;
+  }
+  auto optresult = result.unwrap();
+  if (optresult.isNothing()) {
+    aResult.set(JS::UndefinedValue());
+  } else {
+    // Build return value of the form:
+    // { sum: #, values: {bucket1: count1, ...} }
+    JS::Rooted<JSObject*> root(aCx, JS_NewPlainObject(aCx));
+    if (!root) {
+      return NS_ERROR_FAILURE;
+    }
+    uint64_t sum = optresult.ref().sum;
+    if (!JS_DefineProperty(aCx, root, "sum", static_cast<double>(sum),
+                           JSPROP_ENUMERATE)) {
+      return NS_ERROR_FAILURE;
+    }
+    JS::Rooted<JSObject*> valuesObj(aCx, JS_NewPlainObject(aCx));
+    if (!valuesObj ||
+        !JS_DefineProperty(aCx, root, "values", valuesObj, JSPROP_ENUMERATE)) {
+      return NS_ERROR_FAILURE;
+    }
+    auto& data = optresult.ref().values;
+    for (const auto& entry : data) {
+      const uint64_t bucket = entry.GetKey();
+      const uint64_t count = entry.GetData();
+      if (!JS_DefineProperty(aCx, valuesObj,
+                             nsPrintfCString("%" PRIu64, bucket).get(),
+                             static_cast<double>(count), JSPROP_ENUMERATE)) {
+        return NS_ERROR_FAILURE;
+      }
+    }
+    aResult.setObject(*root);
+  }
+  return NS_OK;
+}
+
+}  // namespace mozilla::glean