Verify custom save path is an absolute path.

PiperOrigin-RevId: 952971544

internal/base/files.cc

@@ -142,4 +142,8 @@ std::optional<size_t> Files::GetAvailableDiskSpaceInBytes(
   return std::nullopt;
 }
 
+bool Files::IsAbsolutePath(const FilePath& path) {
+  return path.path_.is_absolute();
+}
+
 }  // namespace nearby

internal/base/files.h

@@ -75,6 +75,11 @@ class Files {
   // determined.
   static std::optional<size_t> GetAvailableDiskSpaceInBytes(
       const FilePath& path);
+
+  // Returns true if the path is an absolute path.
+  // On Posix systems, this is a path that starts with a `/`.
+  // On Windows, this is a path that starts with a drive letter or a UNC path.
+  static bool IsAbsolutePath(const FilePath& path);
 };
 
 }  // namespace nearby

internal/base/files_test.cc

@@ -46,5 +46,21 @@ TEST(FilesTest, CreateHardLinkSuccess) {
   Files::RemoveFile(target);
 }
 
+#if defined(_WIN32)
+TEST(FilesTest, IsAbsolutePathWindows) {
+  EXPECT_TRUE(Files::IsAbsolutePath(FilePath("C:\\Users\\test\\file.txt")));
+  EXPECT_TRUE(Files::IsAbsolutePath(FilePath("\\\\server\\share\\file.txt")));
+  EXPECT_FALSE(Files::IsAbsolutePath(FilePath("file.txt")));
+  EXPECT_FALSE(Files::IsAbsolutePath(FilePath("C:Users\\test\\file.txt")));
+}
+#endif
+
+#if defined(__linux__) || defined(__APPLE__)
+TEST(FilesTest, IsAbsolutePathPosix) {
+  EXPECT_TRUE(Files::IsAbsolutePath(FilePath("/Users/test/file.txt")));
+  EXPECT_FALSE(Files::IsAbsolutePath(FilePath("file.txt")));
+}
+#endif
+
 }  // namespace
 }  // namespace nearby

sharing/BUILD

@@ -393,6 +393,7 @@ cc_library(
         "//connections/implementation/analytics:analytics_recorder_impl",
         "//internal/base",
         "//internal/base:file_path",
+        "//internal/base:files",
         "//internal/flags:nearby_flags",
         "//internal/network:url",
         "//internal/platform:base",

sharing/nearby_sharing_service_impl_test.cc

@@ -5231,7 +5231,9 @@ TEST_F(NearbySharingServiceImplTest, InitiatePairingSuccess) {
   EXPECT_EQ(frame->v1().bindings().binding_request().type(),
             service::proto::BindingRequest::FILESYNC);
 
-  preference_manager_.SetString(PrefNames::kCustomSavePath, "Downloads");
+  FilePath custom_save_path = Files::GetTemporaryDirectory();
+  preference_manager_.SetString(PrefNames::kCustomSavePath,
+                                custom_save_path.ToString());
   Frame binding_response_frame;
   binding_response_frame.set_version(Frame::V1);
   binding_response_frame.mutable_v1()->set_type(
@@ -5261,7 +5263,7 @@ TEST_F(NearbySharingServiceImplTest, InitiatePairingSuccess) {
   expected_binding.set_binding_id(kBindingId);
   expected_binding.set_source_name(kDeviceName);
   expected_binding.set_destination_directory(
-      FilePath("Downloads").append(FilePath(kDeviceName)).ToString());
+      FilePath(custom_save_path).append(FilePath(kDeviceName)).ToString());
   expected_binding.set_source_device_type(
       sync::SyncBinding::SOURCE_DEVICE_TYPE_PHONE);
   EXPECT_THAT(binding->sync_bindings(0), EqualsProto(expected_binding));
@@ -5336,7 +5338,9 @@ TEST_F(NearbySharingServiceImplTest,
   EXPECT_EQ(frame->v1().bindings().binding_request().type(),
             service::proto::BindingRequest::FILESYNC);
 
-  preference_manager_.SetString(PrefNames::kCustomSavePath, "Downloads");
+  FilePath custom_save_path = Files::GetTemporaryDirectory();
+  preference_manager_.SetString(PrefNames::kCustomSavePath,
+                                custom_save_path.ToString());
   Frame binding_response_frame;
   binding_response_frame.set_version(Frame::V1);
   binding_response_frame.mutable_v1()->set_type(
@@ -5363,7 +5367,7 @@ TEST_F(NearbySharingServiceImplTest,
   expected_binding.set_binding_id(kBindingId);
   expected_binding.set_source_name(kDeviceName);
   expected_binding.set_destination_directory(
-      FilePath("Downloads").append(FilePath(kDeviceName)).ToString());
+      FilePath(custom_save_path).append(FilePath(kDeviceName)).ToString());
   expected_binding.set_source_device_type(
       sync::SyncBinding::SOURCE_DEVICE_TYPE_PHONE);
   EXPECT_THAT(binding->sync_bindings(0), EqualsProto(expected_binding));

sharing/nearby_sharing_settings.cc

@@ -26,6 +26,8 @@
 #include "absl/strings/string_view.h"
 #include "absl/synchronization/mutex.h"
 #include "absl/time/time.h"
+#include "internal/base/file_path.h"
+#include "internal/base/files.h"
 #include "internal/platform/clock.h"
 #include "internal/platform/implementation/device_info.h"
 #include "internal/platform/task_runner.h"
@@ -184,8 +186,12 @@ void NearbyShareSettings::RestoreFallbackVisibility() {
 }
 
 std::string NearbyShareSettings::GetCustomSavePath() const {
-  return preference_manager_.GetString(
+  std::string custom_save_path = preference_manager_.GetString(
       PrefNames::kCustomSavePath, device_info_.GetDownloadPath().ToString());
+  if (Files::IsAbsolutePath(FilePath(custom_save_path))) {
+    return custom_save_path;
+  }
+  return device_info_.GetDownloadPath().ToString();
 }
 
 SyncBindingPrefs NearbyShareSettings::GetSyncBindingPrefs() const {
@@ -347,6 +353,10 @@ void NearbyShareSettings::SetFallbackVisibility(DeviceVisibility visibility) {
 
 void NearbyShareSettings::SetCustomSavePathAsync(
     absl::string_view save_path, const std::function<void()>& callback) {
+  if (!Files::IsAbsolutePath(FilePath(save_path))) {
+    callback();
+    return;
+  }
   absl::MutexLock lock(mutex_);
   preference_manager_.SetString(PrefNames::kCustomSavePath, save_path);
   callback();