Add guards to metric values; erase bad events/metrics from db

chrome/browser/performance_monitor/metric.cc

 // Copyright (c) 2012 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 "chrome/browser/performance_monitor/metric.h"
 
+#include "base/basictypes.h"
 #include "base/logging.h"
 #include "base/string_number_conversions.h"
 
 namespace performance_monitor {
 
+namespace {
+
+// These constants are designed to keep metrics reasonable. However, due to the
+// variety of system configurations which can run chrome, these values may not
+// catch *all* erroneous values. For instance, on a one-CPU machine, any CPU
+// usage > 100 is erroneous, but on a 16-CPU machine, it's perfectly normal.
+// These are "best-guesses" in order to weed out obviously-false values.
+const double kMinUndefined = 0.0;
+const double kMaxUndefined = 0.0;  // No undefined metric is valid.
+const double kMinCpuUsage = 0.0;
+const double kMaxCpuUsage = 100000.0;  // 100% on a 1000-CPU machine.
+const double kMinPrivateMemoryUsage = 0.0;
+const double kMaxPrivateMemoryUsage =
+    1024.0 * 1024.0 * 1024.0 * 1024.0;  // 1 TB
+const double kMinSharedMemoryUsage = 0.0;
+const double kMaxSharedMemoryUsage = 1024.0 * 1024.0 * 1024.0 * 1024.0;  // 1 TB
+const double kMinStartupTime = 0.0;
+const double kMaxStartupTime = 1000000 * 60 * 15;  // 15 minutes
+const double kMinTestStartupTime = 0.0;
+const double kMaxTestStartupTime = 1000000 * 60 * 15;  // 15 minutes
+const double kMinSessionRestoreTime = 0.0;
+const double kMaxSessionRestoreTime = 1000000 * 60 * 15;  // 15 minutes
+const double kMinPageLoadTime = 0.0;
+const double kMaxPageLoadTime = 1000000 * 60 * 15;  // 15 minutes
+const double kMinNetworkBytesRead = 0.0;
+// There really isn't a feasible "max" for network bytes read (even numbers in
+// high TB are potentially possible).
+const double kMaxNetworkBytesRead = static_cast<double>(kint64max);
+
+struct MetricBound {
+  double min;
+  double max;
+};
+
+const MetricBound kMetricBounds[] = {
+ { kMinUndefined, kMaxUndefined },
+ { kMinCpuUsage, kMaxCpuUsage },
+ { kMinPrivateMemoryUsage, kMaxPrivateMemoryUsage },
+ { kMinSharedMemoryUsage, kMaxSharedMemoryUsage },
+ { kMinStartupTime, kMaxStartupTime },
+ { kMinTestStartupTime, kMaxTestStartupTime },
+ { kMinSessionRestoreTime, kMaxSessionRestoreTime },
+ { kMinPageLoadTime, kMaxPageLoadTime },
+ { kMinNetworkBytesRead, kMaxNetworkBytesRead },
+};
+
+COMPILE_ASSERT(ARRAYSIZE_UNSAFE(kMetricBounds) == METRIC_NUMBER_OF_METRICS,
+               metric_bounds_size_doesnt_match_metric_count);
+
+}  // namespace
+
 Metric::Metric() {
   value = 0.0;
 }
 
-Metric::Metric(const base::Time& metric_time, const double metric_value)
-    : time(metric_time), value(metric_value) {
+Metric::Metric(MetricType metric_type,
+               const base::Time& metric_time,
+               const double metric_value)
+    : type(metric_type), time(metric_time), value(metric_value) {
 }
 
-Metric::Metric(const std::string& metric_time,
-               const std::string& metric_value) {
+Metric::Metric(MetricType metric_type,
+               const std::string& metric_time,
+               const std::string& metric_value) : type(metric_type) {
   int64 conversion = 0;
   base::StringToInt64(metric_time, &conversion);
   time = base::Time::FromInternalValue(conversion);
   CHECK(base::StringToDouble(metric_value, &value));
 }
 
 Metric::~Metric() {
 }
 
+bool Metric::Validate() const {

[eaugusti, 2012/09/07 23:10:55]

Should this validate the type too?

[Devlin, 2012/09/10 17:49:14]

Done (it'll already return false on Undefined metrics, but now it will return
false if it's METRIC_NUMBER_OF_METRICS, too).

+  return value < kMetricBounds[type].max && value > kMetricBounds[type].min;
+}
+
+std::string Metric::ValueAsString() const {
+  return base::DoubleToString(value);
+}
+
 }  // namespace performance_monitor