Serialize/Deserialize support in HistogramBase

base/metrics/histogram_base.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 "base/metrics/histogram_base.h"
 
 #include <climits>
 
 #include "base/logging.h"
 #include "base/json/json_string_value_serializer.h"
 #include "base/memory/scoped_ptr.h"
+#include "base/metrics/histogram.h"
+#include "base/metrics/histogram_samples.h"
+#include "base/metrics/sparse_histogram.h"
+#include "base/pickle.h"
 #include "base/values.h"
 
 namespace base {
 
 std::string HistogramTypeToString(HistogramType type) {
   switch(type) {
     case HISTOGRAM:
       return "HISTOGRAM";
     case LINEAR_HISTOGRAM:
       return "LINEAR_HISTOGRAM";
     case BOOLEAN_HISTOGRAM:
       return "BOOLEAN_HISTOGRAM";
     case CUSTOM_HISTOGRAM:
       return "CUSTOM_HISTOGRAM";
     case SPARSE_HISTOGRAM:
       return "SPARSE_HISTOGRAM";
     default:
       NOTREACHED();
   }
   return "UNKNOWN";
 }
 
+HistogramBase* DeserializeHistogramInfo(PickleIterator* iter) {
+  int type;
+  if (!iter->ReadInt(&type))
+    return NULL;
+
+  switch (type) {
+    case HISTOGRAM:
+      return Histogram::DeserializeInfoImpl(iter);
+    case LINEAR_HISTOGRAM:
+      return LinearHistogram::DeserializeInfoImpl(iter);
+    case BOOLEAN_HISTOGRAM:
+      return BooleanHistogram::DeserializeInfoImpl(iter);
+    case CUSTOM_HISTOGRAM:
+      return CustomHistogram::DeserializeInfoImpl(iter);
+    case SPARSE_HISTOGRAM:
+      return SparseHistogram::DeserializeInfoImpl(iter);
+    default:
+      return NULL;
+  }
+}
+
+bool DeserializeHistogramAndAddSamples(PickleIterator* iter) {
+  HistogramBase* histogram = DeserializeHistogramInfo(iter);
+
+  if (!histogram)
+    return false;
+
+  if (histogram->flags() & base::HistogramBase::kIPCSerializationSourceFlag) {
+    DVLOG(1) << "Single process mode, histogram observed and not copied: "
+             << histogram->histogram_name();
+    return true;
+  }
+
+  histogram->AddSamplesFromPickle(iter);
+  return true;
+}
+
+
 const HistogramBase::Sample HistogramBase::kSampleType_MAX = INT_MAX;
 
 HistogramBase::HistogramBase(const std::string& name)
     : histogram_name_(name),
       flags_(kNoFlags) {}
 
 HistogramBase::~HistogramBase() {}
 
 void HistogramBase::SetFlags(int32 flags) {
   flags_ |= flags;
 }
 
 void HistogramBase::ClearFlags(int32 flags) {
   flags_ &= ~flags;
 }
 
+bool HistogramBase::SerializeInfo(Pickle* pickle) const {
+  if (!pickle->WriteInt(GetHistogramType()))
+    return false;
+  return SerializeInfoImpl(pickle);
+}
+
 void HistogramBase::WriteJSON(std::string* output) const {
   Count count;
   scoped_ptr<ListValue> buckets(new ListValue());
   GetCountAndBucketData(&count, buckets.get());
   scoped_ptr<DictionaryValue> parameters(new DictionaryValue());
   GetParameters(parameters.get());
 
   JSONStringValueSerializer serializer(output);
   DictionaryValue root;
   root.SetString("name", histogram_name());
   root.SetInteger("count", count);
   root.SetInteger("flags", flags());
   root.Set("params", parameters.release());
   root.Set("buckets", buckets.release());
   serializer.Serialize(root);
 }
 
 }  // namespace base