Implement about:labs

chrome/browser/labs.cc

Index: chrome/browser/labs.cc
diff --git a/chrome/browser/labs.cc b/chrome/browser/labs.cc
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+// Copyright (c) 2010 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/labs.h"
+
+#include <algorithm>
+#include <iterator>
+#include <map>
+#include <set>
+
+#include "app/l10n_util.h"
+#include "base/command_line.h"
+#include "base/values.h"
+#include "chrome/browser/platform_util.h"
+#include "chrome/browser/prefs/pref_service.h"
+#include "chrome/browser/profile.h"
+#include "chrome/common/chrome_switches.h"
+#include "chrome/common/pref_names.h"
+#include "grit/generated_resources.h"
+
+namespace about_labs {
+
+enum { kOsMac = 1 << 0, kOsWin = 1 << 1, kOsLinux = 1 << 2 };
+
+struct Experiment {
+  // The internal name of the experiment. This is never shown to the user.
+  // It _is_ however stored in the prefs file, so you shouldn't change the
+  // name of existing labs.
+  const char* internal_name;
+
+  // String id of the message containing the experiment's name.
+  int visible_name_id;
+
+  // String id of the message containing the experiment's description.
+  int visible_description_id;
+
+  // The platforms the experiment is available on
+  // Needs to be more than a compile-time #ifdef because of profile sync.
+  unsigned supported_platforms;  // bitmask
+
+  // The commandline parameter that's added when this lab is active. This is
+  // different from |internal_name| so that the commandline flag can be
+  // renamed without breaking the prefs file.
+  const char* command_line;
+};
+
+const Experiment kExperiments[] = {
+  {
+    "expose-for-tabs",
+    IDS_LABS_TABPOSE_NAME,
+    IDS_LABS_TABPOSE_DESCRIPTION,
+    kOsMac,
+#if defined(OS_MACOSX)
+    // The switch exists only on OS X.
+    switches::kEnableExposeForTabs
+#else
+    ""
+#endif
+  },
+  {
+    "vertical-tabs",
+    IDS_LABS_LEFTTABS_NAME,
+    IDS_LABS_LEFTTABS_DESCRIPTION,
+    kOsWin,
+    switches::kEnableVerticalTabs
+  }
+};
+
+// Extracts the list of enabled lab experiments from a profile and stores them
+// in a set.
+void GetEnabledLabs(const PrefService* prefs, std::set<std::string>* result) {
+  const ListValue* enabled_experiments = prefs->GetList(
+      prefs::kEnabledLabsExperiments);
+  if (!enabled_experiments)
+    return;
+
+  for (ListValue::const_iterator it = enabled_experiments->begin();
+       it != enabled_experiments->end();
+       ++it) {
+    std::string experiment_name;
+    if (!(*it)->GetAsString(&experiment_name)) {
+      LOG(WARNING) << "Invalid entry in " << prefs::kEnabledLabsExperiments;
+      continue;
+    }
+    result->insert(experiment_name);
+  }
+}
+
+// Takes a set of enabled lab experiments
+void SetEnabledLabs(
+    PrefService* prefs, const std::set<std::string>& enabled_experiments) {
+  ListValue* experiments_list = prefs->GetMutableList(
+      prefs::kEnabledLabsExperiments);
+  if (!experiments_list)
+    return;
+
+  experiments_list->Clear();
+  for (std::set<std::string>::const_iterator it = enabled_experiments.begin();
+       it != enabled_experiments.end();
+       ++it) {
+    experiments_list->Append(new StringValue(*it));
+  }
+}
+
+// Removes all experiments from prefs::kEnabledLabsExperiments that are
+// unknown, to prevent this list to become very long as experiments are added
+// and removed.
+void SanitizeList(PrefService* prefs) {
+  std::set<std::string> known_experiments;
+  for (size_t i = 0; i < arraysize(kExperiments); ++i)
+    known_experiments.insert(kExperiments[i].internal_name);
+
+  std::set<std::string> enabled_experiments;
+  GetEnabledLabs(prefs, &enabled_experiments);
+
+  std::set<std::string> new_enabled_experiments;
+  std::set_intersection(
+      known_experiments.begin(), known_experiments.end(),
+      enabled_experiments.begin(), enabled_experiments.end(),
+      std::inserter(new_enabled_experiments, new_enabled_experiments.begin()));
+
+  SetEnabledLabs(prefs, new_enabled_experiments);
+}
+
+void GetSanitizedEnabledLabs(
+    PrefService* prefs, std::set<std::string>* result) {
+  SanitizeList(prefs);
+  GetEnabledLabs(prefs, result);
+}
+
+int GetCurrentPlatform() {
+#if defined(OS_MACOSX)
+  return kOsMac;
+#elif defined(OS_WIN)
+  return kOsWin;
+#elif defined(OS_LINUX)
+  return kOsLinux;
+#else
+#error Unknown platform
+#endif
+}
+
+bool IsEnabled() {
+#if defined(OS_CHROMEOS)
+  // ChromeOS uses a different mechanism for about:labs; integrated with their
+  // dom ui options.
+  return false;
+#elif defined(GOOGLE_CHROME_BUILD)
+  // Don't enable this on the stable channel.
+  return platform_util::GetVersionStringModifier() != string16();
+#else
+  return true;
+#endif
+}
+
+void ConvertLabsToSwitches(Profile* profile, CommandLine* command_line) {
+  // Do not activate labs features on the stable channel.
+  if (!IsEnabled())
+    return;
+
+  std::set<std::string> enabled_experiments;
+  GetSanitizedEnabledLabs(profile->GetPrefs(), &enabled_experiments);
+
+  std::map<std::string, const Experiment*> experiments;
+  for (size_t i = 0; i < arraysize(kExperiments); ++i)
+    experiments[kExperiments[i].internal_name] = &kExperiments[i];
+
+  for (std::set<std::string>::iterator it = enabled_experiments.begin();
+       it != enabled_experiments.end();
+       ++it) {
+    const std::string& experiment_name = *it;
+    std::map<std::string, const Experiment*>::iterator experiment =
+        experiments.find(experiment_name);
+    DCHECK(experiment != experiments.end());
+    if (experiment == experiments.end())
+      continue;
+
+    command_line->AppendSwitch(experiment->second->command_line);
+  }
+}
+
+ListValue* GetLabsExperimentsData(Profile* profile) {
+  std::set<std::string> enabled_experiments;
+  GetSanitizedEnabledLabs(profile->GetPrefs(), &enabled_experiments);
+
+  int current_platform = GetCurrentPlatform();
+
+  ListValue* experiments_data = new ListValue();
+  for (size_t i = 0; i < arraysize(kExperiments); ++i) {
+    const Experiment& experiment = kExperiments[i];
+    if (!(experiment.supported_platforms & current_platform))
+      continue;
+
+    DictionaryValue* data = new DictionaryValue();
+    data->SetString("internal_name", experiment.internal_name);
+    data->SetString("name",
+                    l10n_util::GetStringUTF16(experiment.visible_name_id));
+    data->SetString("description",
+                    l10n_util::GetStringUTF16(
+                        experiment.visible_description_id));
+    data->SetBoolean("enabled",
+                      enabled_experiments.count(experiment.internal_name) > 0);
+
+    experiments_data->Append(data);
+  }
+  return experiments_data;
+}
+
+static bool needs_restart_ = false;
+
+bool IsRestartNeededToCommitChanges() {
+  return needs_restart_;
+}
+
+void SetExperimentEnabled(
+    Profile* profile, const std::string& internal_name, bool enable) {
+  needs_restart_ = true;
+
+  std::set<std::string> enabled_experiments;
+  GetSanitizedEnabledLabs(profile->GetPrefs(), &enabled_experiments);
+
+  if (enable)
+    enabled_experiments.insert(internal_name);
+  else
+    enabled_experiments.erase(internal_name);
+
+  SetEnabledLabs(profile->GetPrefs(), enabled_experiments);
+}
+
+}  // namespace Labs