Platform-specific prune state storage.

chrome/browser/safe_browsing/incident_reporting/platform_state_store.cc

Index: chrome/browser/safe_browsing/incident_reporting/platform_state_store.cc
diff --git a/chrome/browser/safe_browsing/incident_reporting/platform_state_store.cc b/chrome/browser/safe_browsing/incident_reporting/platform_state_store.cc
new file mode 100644
index 0000000000000000000000000000000000000000..0c657c6587918a955a5a2fda6a55777df1d73bc4
--- /dev/null
+++ b/chrome/browser/safe_browsing/incident_reporting/platform_state_store.cc
@@ -0,0 +1,200 @@
+// Copyright 2015 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.
+
+// This file implements the platform-neutral Load() and Store() functions for a
+// profile's safebrowsing.incidents_sent preference dictionary. The preference
+// dict is converted to a protocol buffer message which is then serialized into
+// a byte array. This serialized data is written to or read from some
+// platform-specific storage via {Read,Write}StoreData implemented elsewhere.
+//
+// A pref dict like so:
+//   { "0": {"key1": "1235"}, {"key2": "6789"}}}
+// is converted to an identical protocol buffer message, where the top-level
+// mapping's keys are of type int, and the nested mappings' values are of type
+// uint32_t.
+
+#include "chrome/browser/safe_browsing/incident_reporting/platform_state_store.h"
+
+#include "base/values.h"
+
+#if defined(USE_PLATFORM_STATE_STORE)
+
+#include "base/metrics/histogram_macros.h"
+#include "base/strings/string_number_conversions.h"
+#include "chrome/browser/safe_browsing/incident_reporting/state_store_data.pb.h"
+#include "third_party/protobuf/src/google/protobuf/repeated_field.h"
+
+#endif  // USE_PLATFORM_STATE_STORE
+
+namespace safe_browsing {
+namespace platform_state_store {
+
+#if defined(USE_PLATFORM_STATE_STORE)
+
+namespace {
+
+using google::protobuf::RepeatedPtrField;
+
+// Copies the (key, digest) pairs from |keys_and_digests| (a dict of string
+// values) to the |key_digest_pairs| protobuf.
+void KeysAndDigestsToProtobuf(
+    const base::DictionaryValue& keys_and_digests,
+    RepeatedPtrField<StateStoreData::Incidents::KeyDigestMapFieldEntry>*
+        key_digest_pairs) {
+  for (base::DictionaryValue::Iterator iter(keys_and_digests); !iter.IsAtEnd();
+       iter.Advance()) {
+    const base::StringValue* digest_value = nullptr;
+    if (!iter.value().GetAsString(&digest_value)) {
+      NOTREACHED();
+      continue;
+    }
+    uint32_t digest = 0;
+    if (!base::StringToUint(digest_value->GetString(), &digest)) {
+      NOTREACHED();
+      continue;
+    }
+    StateStoreData::Incidents::KeyDigestMapFieldEntry* key_digest =
+        key_digest_pairs->Add();
+    key_digest->set_key(iter.key());
+    key_digest->set_digest(digest);
+  }
+}
+
+// Copies the (type, dict) pairs from |incidents_sent| (a dict of dict values)
+// to the |typed_incidents| protobuf.
+void IncidentsSentToProtobuf(
+    const base::DictionaryValue& incidents_sent,
+    RepeatedPtrField<StateStoreData::TypeIncidentsMapFieldEntry>*
+        type_incidents_pairs) {
+  for (base::DictionaryValue::Iterator iter(incidents_sent); !iter.IsAtEnd();
+       iter.Advance()) {
+    const base::DictionaryValue* keys_and_digests = nullptr;
+    if (!iter.value().GetAsDictionary(&keys_and_digests)) {
+      NOTREACHED();
+      continue;
+    }
+    if (keys_and_digests->empty())
+      continue;
+    int incident_type = 0;
+    if (!base::StringToInt(iter.key(), &incident_type)) {
+      NOTREACHED();
+      continue;
+    }
+    StateStoreData::TypeIncidentsMapFieldEntry* entry =
+        type_incidents_pairs->Add();
+    entry->set_type(incident_type);
+    KeysAndDigestsToProtobuf(
+        *keys_and_digests, entry->mutable_incidents()->mutable_key_to_digest());
+  }
+}
+
+// Copies the (key, digest) pairs for a specific incident type into |type_dict|
+// (a dict of string values).
+void RestoreOfTypeFromProtobuf(
+    const RepeatedPtrField<StateStoreData::Incidents::KeyDigestMapFieldEntry>&
+        key_digest_pairs,
+    base::DictionaryValue* type_dict) {
+  for (const auto& key_digest : key_digest_pairs) {
+    if (!key_digest.has_key() || !key_digest.has_digest())
+      continue;
+    type_dict->SetStringWithoutPathExpansion(
+        key_digest.key(), base::UintToString(key_digest.digest()));
+  }
+}
+
+// Copies the (type, dict) pairs into |value_dict| (a dict of dict values).
+void RestoreFromProtobuf(
+    const RepeatedPtrField<StateStoreData::TypeIncidentsMapFieldEntry>&
+        type_incidents_pairs,
+    base::DictionaryValue* value_dict) {
+  for (const auto& type_incidents : type_incidents_pairs) {
+    if (!type_incidents.has_type() || !type_incidents.has_incidents() ||
+        type_incidents.incidents().key_to_digest_size() == 0) {
+      continue;
+    }
+    std::string type_string(base::IntToString(type_incidents.type()));
+    base::DictionaryValue* type_dict = nullptr;
+    if (!value_dict->GetDictionaryWithoutPathExpansion(type_string,
+                                                       &type_dict)) {
+      type_dict = new base::DictionaryValue();
+      value_dict->SetWithoutPathExpansion(type_string, type_dict);
+    }
+    RestoreOfTypeFromProtobuf(type_incidents.incidents().key_to_digest(),
+                              type_dict);
+  }
+}
+
+}  // namespace
+
+#endif  // USE_PLATFORM_STATE_STORE
+
+scoped_ptr<base::DictionaryValue> Load(Profile* profile) {
+#if defined(USE_PLATFORM_STATE_STORE)
+  scoped_ptr<base::DictionaryValue> value_dict(new base::DictionaryValue());
+  std::string data;
+  PlatformStateStoreLoadResult result = ReadStoreData(profile, &data);
+  if (result == PlatformStateStoreLoadResult::SUCCESS)
+    result = DeserializeIncidentsSent(data, value_dict.get());
+  switch (result) {
+    case PlatformStateStoreLoadResult::SUCCESS:
+    case PlatformStateStoreLoadResult::CLEARED_DATA:
+    case PlatformStateStoreLoadResult::CLEARED_NO_DATA:
+      // Return a (possibly empty) dictionary for the success cases.
+      break;
+    case PlatformStateStoreLoadResult::DATA_CLEAR_FAILED:
+    case PlatformStateStoreLoadResult::OPEN_FAILED:
+    case PlatformStateStoreLoadResult::READ_FAILED:
+    case PlatformStateStoreLoadResult::PARSE_ERROR:
+      // Return null for all error cases.
+      value_dict.reset();
+      break;
+  }
+  UMA_HISTOGRAM_ENUMERATION(
+      "SBIRS.PSSLoadResult", static_cast<uint32_t>(result),
+      static_cast<uint32_t>(PlatformStateStoreLoadResult::NUM_RESULTS));
+  return value_dict.Pass();
+#else
+  return scoped_ptr<base::DictionaryValue>();
+#endif
+}
+
+void Store(Profile* profile, const base::DictionaryValue* incidents_sent) {
+#if defined(USE_PLATFORM_STATE_STORE)
+  std::string data;
+  SerializeIncidentsSent(incidents_sent, &data);
+  UMA_HISTOGRAM_COUNTS("SBIRS.PSSDataStoreSize", data.size());
+  WriteStoreData(profile, data);
+#endif
+}
+
+#if defined(USE_PLATFORM_STATE_STORE)
+
+void SerializeIncidentsSent(const base::DictionaryValue* incidents_sent,
+                            std::string* data) {
+  StateStoreData store_data;
+
+  IncidentsSentToProtobuf(*incidents_sent,
+                          store_data.mutable_type_to_incidents());
+  store_data.SerializeToString(data);
+}
+
+PlatformStateStoreLoadResult DeserializeIncidentsSent(
+    const std::string& data,
+    base::DictionaryValue* value_dict) {
+  StateStoreData store_data;
+  if (data.empty()) {
+    value_dict->Clear();
+    return PlatformStateStoreLoadResult::SUCCESS;
+  }
+  if (!store_data.ParseFromString(data))
+    return PlatformStateStoreLoadResult::PARSE_ERROR;
+  value_dict->Clear();
+  RestoreFromProtobuf(store_data.type_to_incidents(), value_dict);
+  return PlatformStateStoreLoadResult::SUCCESS;
+}
+
+#endif  // USE_PLATFORM_STATE_STORE
+
+}  // namespace platform_state_store
+}  // namespace safe_browsing