Fix crash caused by invalid preferences

PiperOrigin-RevId: 533179434

internal/platform/implementation/windows/preferences_manager.cc

@@ -194,6 +194,12 @@ bool PreferencesManager::Commit() {
 }
 
 bool PreferencesManager::SetValue(absl::string_view key, const json& value) {
+  if (!value_.is_object()) {
+    NEARBY_LOGS(ERROR) << "Preferences is no longer an object! value_="
+                       << value_.dump(4);
+    value_ = json::object();
+  }
+
   if (value_[absl::StrCat(key)] == value) {
     return false;
   }
@@ -205,6 +211,12 @@ bool PreferencesManager::SetValue(absl::string_view key, const json& value) {
 template <typename T>
 T PreferencesManager::GetValue(absl::string_view key,
                                const T& default_value) const {
+  if (!value_.is_object()) {
+    NEARBY_LOGS(ERROR) << "Preferences is no longer an object! value_="
+                       << value_.dump(4);
+    return default_value;
+  }
+
   auto it = value_.find(absl::StrCat(key));
   if (it == value_.end()) {
     return default_value;
@@ -215,6 +227,12 @@ T PreferencesManager::GetValue(absl::string_view key,
 template <typename T>
 bool PreferencesManager::SetArrayValue(absl::string_view key,
                                        absl::Span<const T> value) {
+  if (!value_.is_object()) {
+    NEARBY_LOGS(ERROR) << "Preferences is no longer an object! value_="
+                       << value_.dump(4);
+    value_ = json::object();
+  }
+
   json array_value = json::array();
   for (const T& item_value : value) {
     array_value.push_back(item_value);
@@ -233,6 +251,16 @@ std::vector<T> PreferencesManager::GetArrayValue(
     absl::string_view key, absl::Span<const T> default_value) const {
   std::vector<T> result;
 
+  if (!value_.is_object()) {
+    NEARBY_LOGS(ERROR) << "Preferences is no longer an object! value_="
+                       << value_.dump(4);
+
+    for (const T& value : default_value) {
+      result.push_back(value);
+    }
+    return result;
+  }
+
   auto array_value = value_.find(absl::StrCat(key));
   if (array_value == value_.end() || !array_value->is_array()) {
     for (const T& value : default_value) {

internal/platform/implementation/windows/preferences_manager_test.cc

@@ -16,8 +16,10 @@
 
 #include <stdint.h>
 
+#include <codecvt>
 #include <filesystem>  // NOLINT(build/c++17)
 #include <fstream>
+#include <locale>
 #include <ostream>
 #include <string>
 #include <vector>
@@ -29,6 +31,7 @@
 #include "absl/types/span.h"
 #include "nlohmann/json.hpp"
 #include "nlohmann/json_fwd.hpp"
+#include "internal/platform/logging.h"
 
 namespace nearby {
 namespace windows {
@@ -38,27 +41,27 @@ constexpr absl::Duration kTimeOut = absl::Milliseconds(200);
 constexpr char kPreferencesFilePath[] = "Google/Nearby/Sharing";
 }  // namespace
 
+
 TEST(PreferencesManager, CorruptedConfigFile) {
   std::filesystem::path settingsPath =
-      std::filesystem::temp_directory_path() / "settings.json";
-  std::ofstream output_stream{settingsPath};
-  output_stream << "{\"data\":8, \"names\": [\"In valid\"}" << std::endl;
-  output_stream.close();
+      std::filesystem::temp_directory_path();
+  std::ofstream output_stream{settingsPath / "preferences.json"};
+  output_stream << "CORRUPTED" << std::endl;
 
-  // Should use an empty setting for a corrupted configuration file.
-  EXPECT_EQ(PreferencesManager(kPreferencesFilePath).GetInteger("data", 100),
+  NEARBY_LOGS(INFO) << "Loading preferences from: " << settingsPath.string();
+  EXPECT_EQ(PreferencesManager(settingsPath.string()).GetInteger("data", 100),
             100);
 }
 
 TEST(PreferencesManager, ValidConfigFile) {
   std::filesystem::path settingsPath =
-      std::filesystem::temp_directory_path() / "settings.json";
-  std::ofstream output_stream{settingsPath};
+      std::filesystem::temp_directory_path();
+  std::ofstream output_stream{settingsPath / "preferences.json"};
   output_stream << "{\"data\":8, \"name\": \"Valid\"}" << std::endl;
   output_stream.close();
 
-  // Should use an empty setting for a corrupted configuration file.
-  EXPECT_EQ(PreferencesManager(kPreferencesFilePath).GetInteger("data", 100),
+  NEARBY_LOGS(INFO) << "Loading preferences from: " << settingsPath.string();
+  EXPECT_EQ(PreferencesManager(settingsPath.string()).GetInteger("data", 100),
             8);
 }
 

internal/platform/implementation/windows/preferences_repository.cc

@@ -37,6 +37,15 @@ json PreferencesRepository::LoadPreferences() {
   absl::MutexLock lock(&mutex_);
   std::optional<json> preferences = AttemptLoad();
   if (preferences.has_value()) {
+    // The top level root should be an object, if it's not then something went
+    // wrong or the file was corrupted.
+    if (!preferences.value().is_object()) {
+      NEARBY_LOGS(ERROR) << "Preferences loaded was not a valid object: "
+                         << preferences.value().dump(4);
+
+      return json::object();
+    }
+
     return preferences.value();
   }
 

internal/platform/implementation/windows/preferences_repository_test.cc

@@ -40,6 +40,25 @@ TEST(PreferencesRepository, LoadWithBadPath) {
   EXPECT_TRUE(result.empty());
 }
 
+TEST(PreferencesRepository, RecoverFromBadPreferences) {
+  std::optional<std::filesystem::path> app_data_path =
+      api::ImplementationPlatform::CreateDeviceInfo()->GetLocalAppDataPath();
+  ASSERT_TRUE(app_data_path.has_value());
+  std::filesystem::path full_path = *app_data_path / kPreferencesPath;
+  std::filesystem::path full_name = full_path / kPreferencesFileName;
+
+  if (std::filesystem::exists(full_name)) {
+    std::filesystem::remove(full_name);
+  }
+
+  std::ofstream pref_file(full_name.c_str());
+  pref_file << "\"Bad top level object\"";
+  pref_file.close();
+
+  PreferencesRepository preferences_repository{full_path.string()};
+  EXPECT_EQ(preferences_repository.LoadPreferences(), json::object());
+}
+
 TEST(PreferencesRepository, SaveAndLoadPreferences) {
   std::optional<std::filesystem::path> app_data_path =
       api::ImplementationPlatform::CreateDeviceInfo()->GetLocalAppDataPath();