Add UMA private PPAPI interface for UMA logging from NaCl plugin

webkit/plugins/ppapi/ppb_uma_private_impl.cc

+// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "webkit/plugins/ppapi/ppb_uma_private_impl.h"
+
+#include "base/metrics/histogram.h"
+#include "ppapi/c/pp_var.h"
+#include "ppapi/c/private/ppb_uma_private.h"
+#include "webkit/glue/webkit_glue.h"
+#include "webkit/plugins/ppapi/var.h"
+
+namespace webkit {
+namespace ppapi {
+
+namespace {
+
+#define RETURN_IF_BAD_ARGS(_name, _sample, _min, _max, _bucket_count) \
+  do { \
+    if (_name.type != PP_VARTYPE_STRING || _name.value.as_id == 0) \
+      return; \
+    if (_min >= _max) \
+      return; \
+    if (_bucket_count <= 1) \
+      return; \
+  } while (0)
+
+void HistogramCustomTimes(PP_Var name,
+                          int64_t sample,
+                          int64_t min, int64_t max,
+                          uint32_t bucket_count) {
+  RETURN_IF_BAD_ARGS(name, sample, min, max, bucket_count);
+
+  scoped_refptr<StringVar> name_string(StringVar::FromPPVar(name));
+  base::Histogram* counter =
+      base::Histogram::FactoryTimeGet(
+          name_string->value(),
+          base::TimeDelta::FromMilliseconds(min),
+          base::TimeDelta::FromMilliseconds(max),
+          bucket_count,
+          base::Histogram::kUmaTargetedHistogramFlag);
+  counter->AddTime(base::TimeDelta::FromMilliseconds(sample));
+}
+
+void HistogramCustomCounts(PP_Var name,
+                           int32_t sample,
+                           int32_t min, int32_t max,
+                           uint32_t bucket_count) {
+  RETURN_IF_BAD_ARGS(name, sample, min, max, bucket_count);
+
+  scoped_refptr<StringVar> name_string(StringVar::FromPPVar(name));
+  base::Histogram* counter =
+      base::Histogram::FactoryGet(
+          name_string->value(),
+          min,
+          max,
+          bucket_count,
+          base::Histogram::kUmaTargetedHistogramFlag);
+  counter->Add(sample);
+}
+
+void HistogramEnumeration(PP_Var name,
+                          int32_t sample,
+                          int32_t boundary_value) {
+  RETURN_IF_BAD_ARGS(name, sample, 1, boundary_value, boundary_value + 1);
+
+  scoped_refptr<StringVar> name_string(StringVar::FromPPVar(name));

[brettw, 2011/04/29 22:11:06]

You still need to check this pointer for NULL. The caller could be corrupt or
malicious and put a random ID into the Var for the string ID. This will return
NULL.

[elijahtaylor (use chromium), 2011/04/29 22:27:04]

Done.

+  base::Histogram* counter =
+      base::LinearHistogram::FactoryGet(
+          name_string->value(),
+          1,
+          boundary_value,
+          boundary_value + 1,
+          base::Histogram::kUmaTargetedHistogramFlag);
+  counter->Add(sample);
+}
+
+}  // namespace
+
+const PPB_UMA_Private ppb_uma = {
+  &HistogramCustomTimes,
+  &HistogramCustomCounts,
+  &HistogramEnumeration,
+};
+
+// static
+const PPB_UMA_Private* PPB_UMA_Private_Impl::GetInterface() {
+  return &ppb_uma;
+}
+
+}  // namespace ppapi
+}  // namespace webkit