Use empty in place of size checks vs 0 (flutter#33151)

Author: cbracken

assets/asset_manager.cc

@@ -60,7 +60,7 @@ std::deque<std::unique_ptr<AssetResolver>> AssetManager::TakeResolvers() {
 // |AssetResolver|
 std::unique_ptr<fml::Mapping> AssetManager::GetAsMapping(
     const std::string& asset_name) const {
-  if (asset_name.size() == 0) {
+  if (asset_name.empty()) {
     return nullptr;
   }
   TRACE_EVENT1("flutter", "AssetManager::GetAsMapping", "name",
@@ -80,7 +80,7 @@ std::vector<std::unique_ptr<fml::Mapping>> AssetManager::GetAsMappings(
     const std::string& asset_pattern,
     const std::optional<std::string>& subdir) const {
   std::vector<std::unique_ptr<fml::Mapping>> mappings;
-  if (asset_pattern.size() == 0) {
+  if (asset_pattern.empty()) {
     return mappings;
   }
   TRACE_EVENT1("flutter", "AssetManager::GetAsMappings", "pattern",
@@ -96,7 +96,7 @@ std::vector<std::unique_ptr<fml::Mapping>> AssetManager::GetAsMappings(
 
 // |AssetResolver|
 bool AssetManager::IsValid() const {
-  return resolvers_.size() > 0;
+  return !resolvers_.empty();
 }
 
 // |AssetResolver|

common/graphics/persistent_cache.cc

@@ -332,7 +332,7 @@ sk_sp<SkData> PersistentCache::load(const SkData& key) {
     return nullptr;
   }
   auto file_name = SkKeyToFilePath(key);
-  if (file_name.size() == 0) {
+  if (file_name.empty()) {
     return nullptr;
   }
   auto result =
@@ -405,7 +405,7 @@ void PersistentCache::store(const SkData& key, const SkData& data) {
 
   auto file_name = SkKeyToFilePath(key);
 
-  if (file_name.size() == 0) {
+  if (file_name.empty()) {
     return;
   }
 

flow/skia_gpu_object.h

@@ -89,7 +89,7 @@ class UnrefQueue : public fml::RefCountedThreadSafe<UnrefQueue<T>> {
       skia_object->unref();
     }
 
-    if (context && skia_objects.size() > 0) {
+    if (context && !skia_objects.empty()) {
       context->performDeferredCleanup(std::chrono::milliseconds(0));
     }
   }

fml/concurrent_message_loop.cc

@@ -78,15 +78,15 @@ void ConcurrentMessageLoop::WorkerMain() {
   while (true) {
     std::unique_lock lock(tasks_mutex_);
     tasks_condition_.wait(lock, [&]() {
-      return tasks_.size() > 0 || shutdown_ || HasThreadTasksLocked();
+      return !tasks_.empty() || shutdown_ || HasThreadTasksLocked();
     });
 
     // Shutdown cannot be read with the task mutex unlocked.
     bool shutdown_now = shutdown_;
     fml::closure task;
     std::vector<fml::closure> thread_tasks;
 
-    if (tasks_.size() != 0) {
+    if (!tasks_.empty()) {
       task = tasks_.front();
       tasks_.pop();
     }

fml/file.cc

@@ -37,7 +37,7 @@ fml::UniqueFD CreateDirectory(const fml::UniqueFD& base_directory,
     return {};
   }
 
-  if (components.size() == 0) {
+  if (components.empty()) {
     return {};
   }
 

fml/mapping.cc

@@ -24,7 +24,7 @@ std::unique_ptr<FileMapping> FileMapping::CreateReadOnly(
 std::unique_ptr<FileMapping> FileMapping::CreateReadOnly(
     const fml::UniqueFD& base_fd,
     const std::string& sub_path) {
-  if (sub_path.size() != 0) {
+  if (!sub_path.empty()) {
     return CreateReadOnly(
         OpenFile(base_fd, sub_path.c_str(), false, FilePermission::kRead), "");
   }
@@ -48,7 +48,7 @@ std::unique_ptr<FileMapping> FileMapping::CreateReadExecute(
 std::unique_ptr<FileMapping> FileMapping::CreateReadExecute(
     const fml::UniqueFD& base_fd,
     const std::string& sub_path) {
-  if (sub_path.size() != 0) {
+  if (!sub_path.empty()) {
     return CreateReadExecute(
         OpenFile(base_fd, sub_path.c_str(), false, FilePermission::kRead), "");
   }

fml/platform/posix/paths_posix.cc

@@ -27,7 +27,7 @@ std::string GetCurrentDirectory() {
 }  // namespace
 
 std::string AbsolutePath(const std::string& path) {
-  if (path.size() > 0) {
+  if (!path.empty()) {
     if (path[0] == '/') {
       // Path is already absolute.
       return path;

fml/platform/win/file_win.cc

@@ -40,7 +40,7 @@ static bool IsAbsolutePath(const char* path) {
   }
 
   auto wpath = Utf8ToWideString({path});
-  if (wpath.size() == 0) {
+  if (wpath.empty()) {
     return false;
   }
 
@@ -107,7 +107,7 @@ static DWORD GetFileAttributesForUtf8Path(const fml::UniqueFD& base_directory,
 std::string CreateTemporaryDirectory() {
   // Get the system temporary directory.
   auto temp_dir_container = GetTemporaryDirectoryPath();
-  if (temp_dir_container.size() == 0) {
+  if (temp_dir_container.empty()) {
     FML_DLOG(ERROR) << "Could not get system temporary directory.";
     return {};
   }
@@ -164,7 +164,7 @@ fml::UniqueFD OpenFile(const char* path,
 
   auto file_name = Utf8ToWideString({path});
 
-  if (file_name.size() == 0) {
+  if (file_name.empty()) {
     return {};
   }
 
@@ -207,7 +207,7 @@ fml::UniqueFD OpenDirectory(const char* path,
 
   auto file_name = Utf8ToWideString({path});
 
-  if (file_name.size() == 0) {
+  if (file_name.empty()) {
     return {};
   }
 

fml/platform/win/paths_win.cc

@@ -19,7 +19,7 @@ constexpr char kFileURLPrefix[] = "file:///";
 constexpr size_t kFileURLPrefixLength = sizeof(kFileURLPrefix) - 1;
 
 size_t RootLength(const std::string& path) {
-  if (path.size() == 0)
+  if (path.empty())
     return 0;
   if (path[0] == '/')
     return 1;

lib/ui/dart_runtime_hooks.cc

@@ -187,7 +187,7 @@ void Logger_PrintString(Dart_NativeArguments args) {
 
   if (dart::bin::ShouldCaptureStdout()) {
     std::stringstream stream;
-    if (tag.size() > 0) {
+    if (!tag.empty()) {
       stream << tag << ": ";
     }
     stream << message;

lib/ui/ui_dart_state.cc

@@ -197,14 +197,14 @@ void UIDartState::LogMessage(const std::string& tag,
                         (int)message.size(), message.c_str());
 #elif defined(FML_OS_IOS)
     std::stringstream stream;
-    if (tag.size() > 0) {
+    if (!tag.empty()) {
       stream << tag << ": ";
     }
     stream << message;
     std::string log = stream.str();
     syslog(1 /* LOG_ALERT */, "%.*s", (int)log.size(), log.c_str());
 #else
-    if (tag.size() > 0) {
+    if (!tag.empty()) {
       std::cout << tag << ": ";
     }
     std::cout << message << std::endl;

runtime/dart_lifecycle_unittests.cc

@@ -48,7 +48,7 @@ static std::shared_ptr<DartIsolate> CreateAndRunRootIsolate(
     const DartVMData& vm,
     fml::RefPtr<fml::TaskRunner> task_runner,
     std::string entrypoint) {
-  FML_CHECK(entrypoint.size() > 0);
+  FML_CHECK(!entrypoint.empty());
   TaskRunners runners("io.flutter.test", task_runner, task_runner, task_runner,
                       task_runner);
 

runtime/dart_snapshot.cc

@@ -63,7 +63,7 @@ static std::shared_ptr<const fml::Mapping> SearchMapping(
   }
 
   // Attempt to open file at path specified.
-  if (file_path.size() > 0) {
+  if (!file_path.empty()) {
     if (auto file_mapping = GetFileMapping(file_path, is_executable)) {
       return file_mapping;
     }

runtime/service_protocol.cc

@@ -193,7 +193,7 @@ bool ServiceProtocol::HandleMessage(std::string_view method,
 
   fml::SharedLock lock(*handlers_mutex_);
 
-  if (handlers_.size() == 0) {
+  if (handlers_.empty()) {
     WriteServerErrorResponse(response,
                              "There are no running service protocol handlers.");
     return false;

shell/common/shell.cc

@@ -107,7 +107,7 @@ void PerformInitializationTasks(Settings& settings) {
     }
 
     if (settings.icu_initialization_required) {
-      if (settings.icu_data_path.size() != 0) {
+      if (!settings.icu_data_path.empty()) {
         fml::icu::InitializeICU(settings.icu_data_path);
       } else if (settings.icu_mapper) {
         fml::icu::InitializeICUFromMapping(settings.icu_mapper());

shell/common/shell_unittests.cc

@@ -237,7 +237,7 @@ static void ValidateDestroyPlatformView(Shell* shell) {
 }
 
 static std::string CreateFlagsString(std::vector<const char*>& flags) {
-  if (flags.size() == 0) {
+  if (flags.empty()) {
     return "";
   }
   std::string flags_string = flags[0];
@@ -649,7 +649,7 @@ TEST_F(ShellTest, ReportTimingsIsCalled) {
   DestroyShell(std::move(shell));
 
   fml::TimePoint finish = fml::TimePoint::Now();
-  ASSERT_TRUE(timestamps.size() > 0);
+  ASSERT_TRUE(!timestamps.empty());
   ASSERT_TRUE(timestamps.size() % FrameTiming::kCount == 0);
   std::vector<FrameTiming> timings(timestamps.size() / FrameTiming::kCount);
 

shell/common/switches.cc

@@ -377,11 +377,11 @@ Settings SettingsFromCommandLine(const fml::CommandLine& command_line) {
       FlagForSwitch(Switch::IsolateSnapshotInstructions),
       &isolate_snapshot_instr_filename);
 
-  if (aot_shared_library_name.size() > 0) {
+  if (!aot_shared_library_name.empty()) {
     for (std::string_view name : aot_shared_library_name) {
       settings.application_library_path.emplace_back(name);
     }
-  } else if (snapshot_asset_path.size() > 0) {
+  } else if (!snapshot_asset_path.empty()) {
     settings.vm_snapshot_data_path =
         fml::paths::JoinPaths({snapshot_asset_path, vm_snapshot_data_filename});
     settings.vm_snapshot_instr_path = fml::paths::JoinPaths(

shell/platform/android/android_shell_holder.cc

@@ -337,13 +337,13 @@ std::optional<RunConfiguration> AndroidShellHolder::BuildRunConfiguration(
                           std::move(asset_manager));
 
   {
-    if ((entrypoint.size() > 0) && (libraryUrl.size() > 0)) {
+    if (!entrypoint.empty() && !libraryUrl.empty()) {
       config.SetEntrypointAndLibrary(std::move(entrypoint),
                                      std::move(libraryUrl));
-    } else if (entrypoint.size() > 0) {
+    } else if (!entrypoint.empty()) {
       config.SetEntrypoint(std::move(entrypoint));
     }
-    if (entrypoint_args.size() > 0) {
+    if (!entrypoint_args.empty()) {
       config.SetEntrypointArgs(std::move(entrypoint_args));
     }
   }

shell/platform/android/external_view_embedder/external_view_embedder.cc

@@ -242,7 +242,7 @@ PostPrerollResult AndroidExternalViewEmbedder::PostPrerollAction(
 }
 
 bool AndroidExternalViewEmbedder::FrameHasPlatformLayers() {
-  return composition_order_.size() > 0;
+  return !composition_order_.empty();
 }
 
 // |ExternalViewEmbedder|

shell/platform/android/external_view_embedder/surface_pool.cc

@@ -80,7 +80,7 @@ void SurfacePool::RecycleLayers() {
 
 bool SurfacePool::HasLayers() {
   std::lock_guard lock(mutex_);
-  return layers_.size() > 0;
+  return !layers_.empty();
 }
 
 void SurfacePool::DestroyLayers(
@@ -91,7 +91,7 @@ void SurfacePool::DestroyLayers(
 
 void SurfacePool::DestroyLayersLocked(
     std::shared_ptr<PlatformViewAndroidJNI> jni_facade) {
-  if (layers_.size() == 0) {
+  if (layers_.empty()) {
     return;
   }
   jni_facade->FlutterViewDestroyOverlaySurfaces();

shell/platform/android/platform_view_android_delegate/platform_view_android_delegate.cc

@@ -209,12 +209,12 @@ void PlatformViewAndroidDelegate::UpdateSemantics(
 
     // Calling NewDirectByteBuffer in API level 22 and below with a size of zero
     // will cause a JNI crash.
-    if (actions_buffer.size() > 0) {
+    if (!actions_buffer.empty()) {
       jni_facade_->FlutterViewUpdateCustomAccessibilityActions(actions_buffer,
                                                                action_strings);
     }
 
-    if (buffer.size() > 0) {
+    if (!buffer.empty()) {
       jni_facade_->FlutterViewUpdateSemantics(buffer, strings,
                                               string_attribute_args);
     }

shell/platform/common/accessibility_bridge.cc

@@ -263,7 +263,7 @@ void AccessibilityBridge::SetRoleFromFlutterUpdate(ui::AXNodeData& node_data,
   }
   // If the state cannot be derived from the flutter flags, we fallback to group
   // or static text.
-  if (node.children_in_traversal_order.size() == 0) {
+  if (node.children_in_traversal_order.empty()) {
     node_data.role = ax::mojom::Role::kStaticText;
   } else {
     node_data.role = ax::mojom::Role::kGroup;
@@ -346,7 +346,7 @@ void AccessibilityBridge::SetBooleanAttributesFromFlutterUpdate(
       actions & FlutterSemanticsAction::kFlutterSemanticsActionTap);
   // TODO(chunhtai): figure out if there is a node that does not clip overflow.
   node_data.AddBoolAttribute(ax::mojom::BoolAttribute::kClipsChildren,
-                             node.children_in_traversal_order.size() != 0);
+                             !node.children_in_traversal_order.empty());
   node_data.AddBoolAttribute(
       ax::mojom::BoolAttribute::kSelected,
       flags & FlutterSemanticsFlag::kFlutterSemanticsFlagIsSelected);

shell/platform/darwin/ios/framework/Source/FlutterDartProject.mm

@@ -66,7 +66,7 @@
     // TODO(cbracken): replace this with os_log-based approach.
     // https://github.com/flutter/flutter/issues/44030
     std::stringstream stream;
-    if (tag.size() > 0) {
+    if (!tag.empty()) {
       stream << tag << ": ";
     }
     stream << message;
@@ -78,7 +78,7 @@
   // defaults.
 
   // Flutter ships the ICU data file in the bundle of the engine. Look for it there.
-  if (settings.icu_data_path.size() == 0) {
+  if (settings.icu_data_path.empty()) {
     NSString* icuDataPath = [engineBundle pathForResource:@"icudtl" ofType:@"dat"];
     if (icuDataPath.length > 0) {
       settings.icu_data_path = icuDataPath.UTF8String;
@@ -94,7 +94,7 @@
     }
 
     // No application bundle specified.  Try a known location from the main bundle's Info.plist.
-    if (settings.application_library_path.size() == 0) {
+    if (settings.application_library_path.empty()) {
       NSString* libraryName = [mainBundle objectForInfoDictionaryKey:@"FLTLibraryPath"];
       NSString* libraryPath = [mainBundle pathForResource:libraryName ofType:@""];
       if (libraryPath.length > 0) {
@@ -107,7 +107,7 @@
 
     // In case the application bundle is still not specified, look for the App.framework in the
     // Frameworks directory.
-    if (settings.application_library_path.size() == 0) {
+    if (settings.application_library_path.empty()) {
       NSString* applicationFrameworkPath = [mainBundle pathForResource:@"Frameworks/App.framework"
                                                                 ofType:@""];
       if (applicationFrameworkPath.length > 0) {
@@ -121,7 +121,7 @@
   }
 
   // Checks to see if the flutter assets directory is already present.
-  if (settings.assets_path.size() == 0) {
+  if (settings.assets_path.empty()) {
     NSString* assetsName = [FlutterDartProject flutterAssetsName:bundle];
     NSString* assetsPath = [bundle pathForResource:assetsName ofType:@""];
 

shell/platform/darwin/ios/framework/Source/FlutterPlatformViews.mm

@@ -255,7 +255,7 @@
 // Make this method check if there are pending view operations instead.
 // Also rename it to `HasPendingViewOperations`.
 bool FlutterPlatformViewsController::HasPlatformViewThisOrNextFrame() {
-  return composition_order_.size() > 0 || active_composition_order_.size() > 0;
+  return !composition_order_.empty() || !active_composition_order_.empty();
 }
 
 const int FlutterPlatformViewsController::kDefaultMergedLeaseDuration;

shell/platform/darwin/ios/framework/Source/accessibility_bridge.mm

@@ -104,7 +104,7 @@ void PostAccessibilityNotification(UIAccessibilityNotifications notification,
       [newChildren addObject:child];
     }
     object.children = newChildren;
-    if (node.customAccessibilityActions.size() > 0) {
+    if (!node.customAccessibilityActions.empty()) {
       NSMutableArray<FlutterCustomAccessibilityAction*>* accessibilityCustomActions =
           [[[NSMutableArray alloc] init] autorelease];
       for (int32_t action_id : node.customAccessibilityActions) {

shell/platform/darwin/macos/framework/Source/FlutterEngine.mm

@@ -282,7 +282,7 @@ - (BOOL)runWithEntrypoint:(NSString*)entrypoint {
   flutterArguments.assets_path = _project.assetsPath.UTF8String;
   flutterArguments.icu_data_path = _project.ICUDataPath.UTF8String;
   flutterArguments.command_line_argc = static_cast<int>(argv.size());
-  flutterArguments.command_line_argv = argv.size() > 0 ? argv.data() : nullptr;
+  flutterArguments.command_line_argv = argv.empty() ? nullptr : argv.data();
   flutterArguments.platform_message_callback = (FlutterPlatformMessageCallback)OnPlatformMessage;
   flutterArguments.update_semantics_node_callback = [](const FlutterSemanticsNode* node,
                                                        void* user_data) {