Create variations target that depends on base.

components/variations/variations_seed_processor.cc

Index: components/variations/variations_seed_processor.cc
===================================================================
--- components/variations/variations_seed_processor.cc	(revision 0)
+++ components/variations/variations_seed_processor.cc	(working copy)
@@ -0,0 +1,342 @@
+// Copyright 2013 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 "components/variations/variations_seed_processor.h"
+
+#include <map>
+#include <set>
+#include <vector>
+
+#include "base/command_line.h"
+#include "base/metrics/field_trial.h"
+#include "base/stl_util.h"
+#include "base/version.h"
+#include "components/variations/variations_associated_data.h"
+
+namespace chrome_variations {
+
+namespace {
+
+Study_Platform GetCurrentPlatform() {
+#if defined(OS_WIN)
+  return Study_Platform_PLATFORM_WINDOWS;
+#elif defined(OS_IOS)
+  return Study_Platform_PLATFORM_IOS;
+#elif defined(OS_MACOSX)
+  return Study_Platform_PLATFORM_MAC;
+#elif defined(OS_CHROMEOS)
+  return Study_Platform_PLATFORM_CHROMEOS;
+#elif defined(OS_ANDROID)
+  return Study_Platform_PLATFORM_ANDROID;
+#elif defined(OS_LINUX) || defined(OS_BSD) || defined(OS_SOLARIS)
+  // Default BSD and SOLARIS to Linux to not break those builds, although these
+  // platforms are not officially supported by Chrome.
+  return Study_Platform_PLATFORM_LINUX;
+#else
+#error Unknown platform
+#endif
+}
+
+// Converts |date_time| in Study date format to base::Time.
+base::Time ConvertStudyDateToBaseTime(int64 date_time) {
+  return base::Time::UnixEpoch() + base::TimeDelta::FromSeconds(date_time);
+}
+
+}  // namespace
+
+VariationsSeedProcessor::VariationsSeedProcessor() {
+}
+
+VariationsSeedProcessor::~VariationsSeedProcessor() {
+}
+
+void VariationsSeedProcessor::CreateTrialsFromSeed(
+    const TrialsSeed& seed,
+    const std::string& locale,
+    const base::Time& reference_date,
+    const base::Version& version,
+    Study_Channel channel) {
+  DCHECK(version.IsValid());
+
+  // Add expired studies (in a disabled state) only after all the non-expired
+  // studies have been added (and do not add an expired study if a corresponding
+  // non-expired study got added). This way, if there's both an expired and a
+  // non-expired study that applies, the non-expired study takes priority.
+  std::set<std::string> created_studies;
+  std::vector<const Study*> expired_studies;
+
+  for (int i = 0; i < seed.study_size(); ++i) {
+    const Study& study = seed.study(i);
+    if (!ShouldAddStudy(study, locale, reference_date, version, channel))
+      continue;
+
+    if (IsStudyExpired(study, reference_date)) {
+      expired_studies.push_back(&study);
+    } else {
+      CreateTrialFromStudy(study, false);
+      created_studies.insert(study.name());
+    }
+  }
+
+  for (size_t i = 0; i < expired_studies.size(); ++i) {
+    if (!ContainsKey(created_studies, expired_studies[i]->name()))
+      CreateTrialFromStudy(*expired_studies[i], true);
+  }
+}
+
+bool VariationsSeedProcessor::CheckStudyChannel(const Study_Filter& filter,
+                                                Study_Channel channel) {
+  // An empty channel list matches all channels.
+  if (filter.channel_size() == 0)
+    return true;
+
+  for (int i = 0; i < filter.channel_size(); ++i) {
+    if (filter.channel(i) == channel)
+      return true;
+  }
+  return false;
+}
+
+bool VariationsSeedProcessor::CheckStudyLocale(
+    const Study_Filter& filter,
+    const std::string& locale) {
+  // An empty locale list matches all locales.
+  if (filter.locale_size() == 0)
+    return true;
+
+  for (int i = 0; i < filter.locale_size(); ++i) {
+    if (filter.locale(i) == locale)
+      return true;
+  }
+  return false;
+}
+
+bool VariationsSeedProcessor::CheckStudyPlatform(
+    const Study_Filter& filter,
+    Study_Platform platform) {
+  // An empty platform list matches all platforms.
+  if (filter.platform_size() == 0)
+    return true;
+
+  for (int i = 0; i < filter.platform_size(); ++i) {
+    if (filter.platform(i) == platform)
+      return true;
+  }
+  return false;
+}
+
+bool VariationsSeedProcessor::CheckStudyStartDate(
+    const Study_Filter& filter,
+    const base::Time& date_time) {
+  if (filter.has_start_date()) {
+    const base::Time start_date =
+        ConvertStudyDateToBaseTime(filter.start_date());
+    return date_time >= start_date;
+  }
+
+  return true;
+}
+
+bool VariationsSeedProcessor::CheckStudyVersion(
+    const Study_Filter& filter,
+    const base::Version& version) {
+  if (filter.has_min_version()) {
+    if (version.CompareToWildcardString(filter.min_version()) < 0)
+      return false;
+  }
+
+  if (filter.has_max_version()) {
+    if (version.CompareToWildcardString(filter.max_version()) > 0)
+      return false;
+  }
+
+  return true;
+}
+
+void VariationsSeedProcessor::CreateTrialFromStudy(const Study& study,
+                                                   bool is_expired) {
+  base::FieldTrial::Probability total_probability = 0;
+  if (!ValidateStudyAndComputeTotalProbability(study, &total_probability))
+    return;
+
+  // Check if any experiments need to be forced due to a command line
+  // flag. Force the first experiment with an existing flag.
+  CommandLine* command_line = CommandLine::ForCurrentProcess();
+  for (int i = 0; i < study.experiment_size(); ++i) {
+    const Study_Experiment& experiment = study.experiment(i);
+    if (experiment.has_forcing_flag() &&
+        command_line->HasSwitch(experiment.forcing_flag())) {
+      base::FieldTrialList::CreateFieldTrial(study.name(), experiment.name());
+      DVLOG(1) << "Trial " << study.name() << " forced by flag: "
+               << experiment.forcing_flag();
+      return;
+    }
+  }
+
+  uint32 randomization_seed = 0;
+  base::FieldTrial::RandomizationType randomization_type =
+      base::FieldTrial::SESSION_RANDOMIZED;
+  if (study.has_consistency() &&
+      study.consistency() == Study_Consistency_PERMANENT) {
+    randomization_type = base::FieldTrial::ONE_TIME_RANDOMIZED;
+    if (study.has_randomization_seed())
+      randomization_seed = study.randomization_seed();
+  }
+
+  // The trial is created without specifying an expiration date because the
+  // expiration check in field_trial.cc is based on the build date. Instead,
+  // the expiration check using |reference_date| is done explicitly below.
+  scoped_refptr<base::FieldTrial> trial(
+      base::FieldTrialList::FactoryGetFieldTrialWithRandomizationSeed(
+          study.name(), total_probability, study.default_experiment_name(),
+          base::FieldTrialList::kNoExpirationYear, 1, 1, randomization_type,
+          randomization_seed, NULL));
+
+  for (int i = 0; i < study.experiment_size(); ++i) {
+    const Study_Experiment& experiment = study.experiment(i);
+
+    std::map<std::string, std::string> params;
+    for (int j = 0; j < experiment.param_size(); j++) {
+      if (experiment.param(j).has_name() && experiment.param(j).has_value())
+        params[experiment.param(j).name()] = experiment.param(j).value();
+    }
+    if (!params.empty())
+      AssociateVariationParams(study.name(), experiment.name(), params);
+
+    // Groups with flags can't be selected randomly, so we don't add them to
+    // the field trial.
+    if (experiment.has_forcing_flag())
+      continue;
+
+    if (experiment.name() != study.default_experiment_name())
+      trial->AppendGroup(experiment.name(), experiment.probability_weight());
+
+    if (experiment.has_google_web_experiment_id()) {
+      const VariationID variation_id =
+          static_cast<VariationID>(experiment.google_web_experiment_id());
+      AssociateGoogleVariationIDForce(GOOGLE_WEB_PROPERTIES,
+                                      study.name(),
+                                      experiment.name(),
+                                      variation_id);
+    }
+    if (experiment.has_google_update_experiment_id()) {
+      const VariationID variation_id =
+          static_cast<VariationID>(experiment.google_update_experiment_id());
+      AssociateGoogleVariationIDForce(GOOGLE_UPDATE_SERVICE,
+                                      study.name(),
+                                      experiment.name(),
+                                      variation_id);
+    }
+  }
+
+  trial->SetForced();
+  if (is_expired)
+    trial->Disable();
+}
+
+bool VariationsSeedProcessor::IsStudyExpired(const Study& study,
+                                       const base::Time& date_time) {
+  if (study.has_expiry_date()) {
+    const base::Time expiry_date =
+        ConvertStudyDateToBaseTime(study.expiry_date());
+    return date_time >= expiry_date;
+  }
+
+  return false;
+}
+
+bool VariationsSeedProcessor::ShouldAddStudy(
+    const Study& study,
+    const std::string& locale,
+    const base::Time& reference_date,
+    const base::Version& version,
+    Study_Channel channel) {
+  if (study.has_filter()) {
+    if (!CheckStudyChannel(study.filter(), channel)) {
+      DVLOG(1) << "Filtered out study " << study.name() << " due to channel.";
+      return false;
+    }
+
+    if (!CheckStudyLocale(study.filter(), locale)) {
+      DVLOG(1) << "Filtered out study " << study.name() << " due to locale.";
+      return false;
+    }
+
+    if (!CheckStudyPlatform(study.filter(), GetCurrentPlatform())) {
+      DVLOG(1) << "Filtered out study " << study.name() << " due to platform.";
+      return false;
+    }
+
+    if (!CheckStudyVersion(study.filter(), version)) {
+      DVLOG(1) << "Filtered out study " << study.name() << " due to version.";
+      return false;
+    }
+
+    if (!CheckStudyStartDate(study.filter(), reference_date)) {
+      DVLOG(1) << "Filtered out study " << study.name() <<
+                  " due to start date.";
+      return false;
+    }
+  }
+
+  DVLOG(1) << "Kept study " << study.name() << ".";
+  return true;
+}
+
+bool VariationsSeedProcessor::ValidateStudyAndComputeTotalProbability(
+    const Study& study,
+    base::FieldTrial::Probability* total_probability) {
+  // At the moment, a missing default_experiment_name makes the study invalid.
+  if (study.default_experiment_name().empty()) {
+    DVLOG(1) << study.name() << " has no default experiment defined.";
+    return false;
+  }
+  if (study.filter().has_min_version() &&
+      !Version::IsValidWildcardString(study.filter().min_version())) {
+    DVLOG(1) << study.name() << " has invalid min version: "
+             << study.filter().min_version();
+    return false;
+  }
+  if (study.filter().has_max_version() &&
+      !Version::IsValidWildcardString(study.filter().max_version())) {
+    DVLOG(1) << study.name() << " has invalid max version: "
+             << study.filter().max_version();
+    return false;
+  }
+
+  const std::string& default_group_name = study.default_experiment_name();
+  base::FieldTrial::Probability divisor = 0;
+
+  bool found_default_group = false;
+  std::set<std::string> experiment_names;
+  for (int i = 0; i < study.experiment_size(); ++i) {
+    if (study.experiment(i).name().empty()) {
+      DVLOG(1) << study.name() << " is missing experiment " << i << " name";
+      return false;
+    }
+    if (!experiment_names.insert(study.experiment(i).name()).second) {
+      DVLOG(1) << study.name() << " has a repeated experiment name "
+               << study.experiment(i).name();
+      return false;
+    }
+
+    if (!study.experiment(i).has_forcing_flag())
+      divisor += study.experiment(i).probability_weight();
+    if (study.experiment(i).name() == default_group_name)
+      found_default_group = true;
+  }
+
+  if (!found_default_group) {
+    DVLOG(1) << study.name() << " is missing default experiment in its "
+             << "experiment list";
+    // The default group was not found in the list of groups. This study is not
+    // valid.
+    return false;
+  }
+
+  *total_probability = divisor;
+  return true;
+}
+
+}  // namespace chrome_variations