predictors: Refactor the resource_prefetch_predictor database handling.

chrome/browser/predictors/resource_prefetch_predictor_tables.cc

Index: chrome/browser/predictors/resource_prefetch_predictor_tables.cc
diff --git a/chrome/browser/predictors/resource_prefetch_predictor_tables.cc b/chrome/browser/predictors/resource_prefetch_predictor_tables.cc
index a3dd8c1e429adf005511c75f364ad9f0f19045ca..2ed345ed024eae9763bba173c6c434fc58addca5 100644
--- a/chrome/browser/predictors/resource_prefetch_predictor_tables.cc
+++ b/chrome/browser/predictors/resource_prefetch_predictor_tables.cc
@@ -16,13 +16,12 @@
 #include "content/public/browser/browser_thread.h"
 #include "sql/statement.h"
 
+using chrome_browser_predictors::ResourceData;
 using content::BrowserThread;
 using sql::Statement;
 
 namespace {
 
-using ResourceRow = predictors::ResourcePrefetchPredictorTables::ResourceRow;
-
 const char kUrlResourceTableName[] = "resource_prefetch_predictor_url";
 const char kUrlMetadataTableName[] = "resource_prefetch_predictor_url_metadata";
 const char kHostResourceTableName[] = "resource_prefetch_predictor_host";
@@ -35,33 +34,31 @@ const char kInsertMetadataTableStatementTemplate[] =
     "INSERT INTO %s (main_page_url, last_visit_time) VALUES (?,?)";
 const char kDeleteStatementTemplate[] = "DELETE FROM %s WHERE main_page_url=?";
 
-void BindResourceRowToStatement(const ResourceRow& row,
-                                const std::string& primary_key,
-                                Statement* statement) {
-  chrome_browser_predictors::ResourceData proto;
-  row.ToProto(&proto);
-  int size = proto.ByteSize();
-  std::vector<char> proto_buffer(size);
-  proto.SerializeToArray(&proto_buffer[0], size);
+void BindToStatement(const ResourceData& resource,
+                     const std::string& primary_key,
+                     Statement* statement) {
+  int size = resource.ByteSize();
+  std::vector<char> buffer(size);
+  resource.SerializeToArray(&buffer[0], size);
 
   statement->BindString(0, primary_key);
-  statement->BindString(1, row.resource_url.spec());
-  statement->BindBlob(2, &proto_buffer[0], size);
+  statement->BindString(1, resource.resource_url());
+  statement->BindBlob(2, &buffer[0], size);
 }
 
-bool StepAndInitializeResourceRow(Statement* statement, ResourceRow* row) {
+bool StepAndInitializeResource(Statement* statement, ResourceData* resource) {
   if (!statement->Step())
     return false;
+  std::string primary_key = statement->ColumnString(0);
+  std::string resource_url = statement->ColumnString(1);
 
   int size = statement->ColumnByteLength(2);
   const void* data = statement->ColumnBlob(2);
   DCHECK(data);
-  chrome_browser_predictors::ResourceData proto;
-  proto.ParseFromArray(data, size);
-  ResourceRow::FromProto(proto, row);
+  resource->ParseFromArray(data, size);
+  resource->set_primary_key(primary_key);
+  DCHECK(resource_url == resource->resource_url());
 
-  row->primary_key = statement->ColumnString(0);
-  row->resource_url = GURL(statement->ColumnString(1));
   return true;
 }
 
@@ -70,127 +67,39 @@ bool StepAndInitializeResourceRow(Statement* statement, ResourceRow* row) {
 namespace predictors {
 
 // static
-const size_t ResourcePrefetchPredictorTables::kMaxStringLength = 1024;
-
-ResourceRow::ResourceRow()
-    : resource_type(content::RESOURCE_TYPE_LAST_TYPE),
-      number_of_hits(0),
-      number_of_misses(0),
-      consecutive_misses(0),
-      average_position(0.0),
-      priority(net::IDLE),
-      has_validators(false),
-      always_revalidate(false),
-      score(0.0) {}
-
-ResourceRow::ResourceRow(const ResourceRow& other)
-    : primary_key(other.primary_key),
-      resource_url(other.resource_url),
-      resource_type(other.resource_type),
-      number_of_hits(other.number_of_hits),
-      number_of_misses(other.number_of_misses),
-      consecutive_misses(other.consecutive_misses),
-      average_position(other.average_position),
-      priority(other.priority),
-      has_validators(other.has_validators),
-      always_revalidate(other.always_revalidate),
-      score(other.score) {}
-
-ResourceRow::ResourceRow(const std::string& i_primary_key,
-                         const std::string& i_resource_url,
-                         content::ResourceType i_resource_type,
-                         int i_number_of_hits,
-                         int i_number_of_misses,
-                         int i_consecutive_misses,
-                         double i_average_position,
-                         net::RequestPriority i_priority,
-                         bool i_has_validators,
-                         bool i_always_revalidate)
-    : primary_key(i_primary_key),
-      resource_url(i_resource_url),
-      resource_type(i_resource_type),
-      number_of_hits(i_number_of_hits),
-      number_of_misses(i_number_of_misses),
-      consecutive_misses(i_consecutive_misses),
-      average_position(i_average_position),
-      priority(i_priority),
-      has_validators(i_has_validators),
-      always_revalidate(i_always_revalidate) {
-  UpdateScore();
+void ResourcePrefetchPredictorTables::SortResources(
+    std::vector<ResourceData>* resources) {
+  std::sort(resources->begin(), resources->end(),
+            [](const ResourceData& x, const ResourceData& y) {
+              return x.score() > y.score();
+            });
 }
 
-void ResourceRow::UpdateScore() {
+// static
+void ResourcePrefetchPredictorTables::UpdateResourceScore(
+    ResourceData* resource) {
   // The score is calculated so that when the rows are sorted, stylesheets,
   // scripts and fonts appear first, sorted by position(ascending) and then the
   // rest of the resources sorted by position (ascending).
   static const int kMaxResourcesPerType = 100;
+  content::ResourceType resource_type =
+      static_cast<content::ResourceType>(resource->resource_type());
   switch (resource_type) {
     case content::RESOURCE_TYPE_STYLESHEET:
     case content::RESOURCE_TYPE_SCRIPT:
     case content::RESOURCE_TYPE_FONT_RESOURCE:
-      score = (2 * kMaxResourcesPerType) - average_position;
+      resource->set_score((2 * kMaxResourcesPerType) -
+                          resource->average_position());
       break;
 
     case content::RESOURCE_TYPE_IMAGE:
     default:
-      score = kMaxResourcesPerType - average_position;
+      resource->set_score(kMaxResourcesPerType - resource->average_position());
       break;
   }
   // TODO(lizeb): Take priority into account.
 }
 
-bool ResourceRow::operator==(const ResourceRow& rhs) const {
-  return primary_key == rhs.primary_key && resource_url == rhs.resource_url &&
-         resource_type == rhs.resource_type &&
-         number_of_hits == rhs.number_of_hits &&
-         number_of_misses == rhs.number_of_misses &&
-         consecutive_misses == rhs.consecutive_misses &&
-         average_position == rhs.average_position && priority == rhs.priority &&
-         has_validators == rhs.has_validators &&
-         always_revalidate == rhs.always_revalidate && score == rhs.score;
-}
-
-void ResourceRow::ToProto(ResourceData* resource_data) const {
-  using chrome_browser_predictors::ResourceData_Priority;
-  using chrome_browser_predictors::ResourceData_ResourceType;
-
-  resource_data->set_primary_key(primary_key);
-  resource_data->set_resource_url(resource_url.spec());
-  resource_data->set_resource_type(
-      static_cast<ResourceData_ResourceType>(resource_type));
-  resource_data->set_number_of_hits(number_of_hits);
-  resource_data->set_number_of_misses(number_of_misses);
-  resource_data->set_consecutive_misses(consecutive_misses);
-  resource_data->set_average_position(average_position);
-  resource_data->set_priority(static_cast<ResourceData_Priority>(priority));
-  resource_data->set_has_validators(has_validators);
-  resource_data->set_always_revalidate(always_revalidate);
-}
-
-// static
-void ResourceRow::FromProto(const ResourceData& proto, ResourceRow* row) {
-  DCHECK(proto.has_primary_key());
-  row->primary_key = proto.primary_key();
-  row->resource_url = GURL(proto.resource_url());
-  row->resource_type =
-      static_cast<content::ResourceType>(proto.resource_type());
-  row->number_of_hits = proto.number_of_hits();
-  row->number_of_misses = proto.number_of_misses();
-  row->consecutive_misses = proto.consecutive_misses();
-  row->average_position = proto.average_position();
-  row->priority = static_cast<net::RequestPriority>(proto.priority());
-  row->has_validators = proto.has_validators();
-  row->always_revalidate = proto.always_revalidate();
-}
-
-// static
-void ResourcePrefetchPredictorTables::SortResourceRows(ResourceRows* rows) {
-  std::sort(rows->begin(), rows->end(),
-            [](const ResourceRow& x, const ResourceRow& y) {
-              return x.score > y.score;
-            });
-}
-
 ResourcePrefetchPredictorTables::PrefetchData::PrefetchData(
     PrefetchKeyType i_key_type,
     const std::string& i_primary_key)
@@ -206,14 +115,7 @@ ResourcePrefetchPredictorTables::PrefetchData::PrefetchData(
       resources(other.resources) {
 }
 
-ResourcePrefetchPredictorTables::PrefetchData::~PrefetchData() {
-}
-
-bool ResourcePrefetchPredictorTables::PrefetchData::operator==(
-    const PrefetchData& rhs) const {
-  return key_type == rhs.key_type && primary_key == rhs.primary_key &&
-      resources == rhs.resources;
-}
+ResourcePrefetchPredictorTables::PrefetchData::~PrefetchData() {}
 
 void ResourcePrefetchPredictorTables::GetAllData(
     PrefetchDataMap* url_data_map,
@@ -284,18 +186,14 @@ void ResourcePrefetchPredictorTables::DeleteAllData() {
   if (CantAccessDatabase())
     return;
 
-  Statement deleter(DB()->GetUniqueStatement(
-      base::StringPrintf("DELETE FROM %s", kUrlResourceTableName).c_str()));
-  deleter.Run();
-  deleter.Assign(DB()->GetUniqueStatement(
-      base::StringPrintf("DELETE FROM %s", kUrlMetadataTableName).c_str()));
-  deleter.Run();
-  deleter.Assign(DB()->GetUniqueStatement(
-      base::StringPrintf("DELETE FROM %s", kHostResourceTableName).c_str()));
-  deleter.Run();
-  deleter.Assign(DB()->GetUniqueStatement(
-      base::StringPrintf("DELETE FROM %s", kHostMetadataTableName).c_str()));
-  deleter.Run();
+  Statement deleter;
+  for (const char* table_name :
+       {kUrlResourceTableName, kUrlMetadataTableName, kHostResourceTableName,
+        kHostMetadataTableName}) {
+    deleter.Assign(DB()->GetUniqueStatement(
+        base::StringPrintf("DELETE FROM %s", table_name).c_str()));
+    deleter.Run();
+  }
 }
 
 ResourcePrefetchPredictorTables::ResourcePrefetchPredictorTables()
@@ -317,24 +215,23 @@ void ResourcePrefetchPredictorTables::GetAllDataHelper(
   Statement resource_reader(DB()->GetUniqueStatement(
       base::StringPrintf("SELECT * FROM %s", resource_table_name).c_str()));
 
-  ResourceRow row;
-  while (StepAndInitializeResourceRow(&resource_reader, &row)) {
-    row.UpdateScore();
-    std::string primary_key = row.primary_key;
+  ResourceData resource;
+  while (StepAndInitializeResource(&resource_reader, &resource)) {
+    UpdateResourceScore(&resource);
+    std::string primary_key = resource.primary_key();
     // Don't need to store primary key since the data is grouped by primary key.
-    row.primary_key.clear();
-
+    resource.clear_primary_key();
     PrefetchDataMap::iterator it = data_map->find(primary_key);
     if (it == data_map->end()) {
       it = data_map->insert(std::make_pair(
           primary_key, PrefetchData(key_type, primary_key))).first;
     }
-    it->second.resources.push_back(row);
+    it->second.resources.push_back(resource);
   }
 
   // Sort each of the resource row vectors by score.
   for (auto& kv : *data_map)
-    SortResourceRows(&(kv.second.resources));
+    SortResources(&(kv.second.resources));
 
   // Read the metadata and keep track of entries that have metadata, but no
   // resource entries, so they can be deleted.
@@ -380,13 +277,11 @@ bool ResourcePrefetchPredictorTables::UpdateDataHelper(
     return false;
 
   // Add the new data to the tables.
-  const ResourceRows& resources = data.resources;
-  for (const ResourceRow& resource : resources) {
+  for (const ResourceData& resource : data.resources) {
     std::unique_ptr<Statement> resource_inserter(
         data.is_host() ? GetHostResourceUpdateStatement()
                        : GetUrlResourceUpdateStatement());
-    BindResourceRowToStatement(resource, data.primary_key,
-                               resource_inserter.get());
+    BindToStatement(resource, data.primary_key, resource_inserter.get());
     if (!resource_inserter->Run())
       return false;
   }
@@ -407,29 +302,28 @@ void ResourcePrefetchPredictorTables::DeleteDataHelper(
     const std::vector<std::string>& keys) {
   bool is_host = key_type == PREFETCH_KEY_TYPE_HOST;
 
-  for (std::vector<std::string>::const_iterator it = keys.begin();
-       it != keys.end(); ++it) {
+  for (const std::string& key : keys) {
     std::unique_ptr<Statement> deleter(is_host
                                            ? GetHostResourceDeleteStatement()
                                            : GetUrlResourceDeleteStatement());
-    deleter->BindString(0, *it);
+    deleter->BindString(0, key);
     deleter->Run();
 
-    deleter.reset(is_host ? GetHostMetadataDeleteStatement() :
-        GetUrlMetadataDeleteStatement());
-    deleter->BindString(0, *it);
+    deleter.reset(is_host ? GetHostMetadataDeleteStatement()
+                          : GetUrlMetadataDeleteStatement());
+    deleter->BindString(0, key);
     deleter->Run();
   }
 }
 
+// static
 bool ResourcePrefetchPredictorTables::StringsAreSmallerThanDBLimit(
-    const PrefetchData& data) const {
+    const PrefetchData& data) {
   if (data.primary_key.length() > kMaxStringLength)
     return false;
 
-  for (ResourceRows::const_iterator it = data.resources.begin();
-       it != data.resources.end(); ++it) {
-    if (it->resource_url.spec().length() > kMaxStringLength)
+  for (const ResourceData& resource : data.resources) {
+    if (resource.resource_url().length() > kMaxStringLength)
       return false;
   }
   return true;