Return errors immediately on read-only roots.

If write-related functions are called on read-only roots, we can return
errors immediately instead of making mojo calls which always fail.

Bug: 956852
Test: Ran unit_tests
Change-Id: I81bbe3aea12f683ecf7dc89db698983d35202a67
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2346101Reviewed-by: Shuhei Takahashi <nya@chromium.org>
Commit-Queue: Naoki Fukino <fukino@chromium.org>
Cr-Commit-Position: refs/heads/master@{#796740}

chrome/browser/chromeos/arc/fileapi/arc_documents_provider_root.cc

@@ -141,6 +141,10 @@ void ArcDocumentsProviderRoot::ReadDirectory(const base::FilePath& path,
 void ArcDocumentsProviderRoot::DeleteFile(const base::FilePath& path,
                                           StatusCallback callback) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
+  if (read_only_) {
+    std::move(callback).Run(base::File::FILE_ERROR_ACCESS_DENIED);
+    return;
+  }
   ResolveToDocumentId(
       path,
       base::BindOnce(&ArcDocumentsProviderRoot::DeleteFileWithDocumentId,
@@ -150,6 +154,10 @@ void ArcDocumentsProviderRoot::DeleteFile(const base::FilePath& path,
 void ArcDocumentsProviderRoot::CreateFile(const base::FilePath& path,
                                           StatusCallback callback) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
+  if (read_only_) {
+    std::move(callback).Run(base::File::FILE_ERROR_ACCESS_DENIED);
+    return;
+  }
   ResolveToDocumentId(
       path, base::BindOnce(
                 &ArcDocumentsProviderRoot::CreateFileAfterConflictCheck,
@@ -159,6 +167,10 @@ void ArcDocumentsProviderRoot::CreateFile(const base::FilePath& path,
 void ArcDocumentsProviderRoot::CreateDirectory(const base::FilePath& path,
                                                StatusCallback callback) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
+  if (read_only_) {
+    std::move(callback).Run(base::File::FILE_ERROR_ACCESS_DENIED);
+    return;
+  }
   ResolveToDocumentId(
       path, base::BindOnce(
                 &ArcDocumentsProviderRoot::CreateDirectoryAfterConflictCheck,
@@ -169,6 +181,10 @@ void ArcDocumentsProviderRoot::CopyFileLocal(const base::FilePath& src_path,
                                              const base::FilePath& dest_path,
                                              StatusCallback callback) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
+  if (read_only_) {
+    std::move(callback).Run(base::File::FILE_ERROR_ACCESS_DENIED);
+    return;
+  }
   if (src_path == dest_path) {
     std::move(callback).Run(base::File::FILE_ERROR_INVALID_OPERATION);
     return;
@@ -184,6 +200,10 @@ void ArcDocumentsProviderRoot::MoveFileLocal(const base::FilePath& src_path,
                                              const base::FilePath& dest_path,
                                              StatusCallback callback) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
+  if (read_only_) {
+    std::move(callback).Run(base::File::FILE_ERROR_ACCESS_DENIED);
+    return;
+  }
   if (src_path.DirName() == dest_path.DirName()) {
     RenameFileInternal(src_path, dest_path.BaseName().value(),
                        std::move(callback));

chrome/browser/chromeos/arc/fileapi/arc_documents_provider_root.h

@@ -86,6 +86,9 @@ class ArcDocumentsProviderRoot : public ArcFileSystemOperationRunner::Observer {
                      ReadDirectoryCallback callback);
 
   // Deletes a file/directory at the given path.
+  //
+  // - File::FILE_ERROR_NOT_FOUND if |path| does not exist.
+  // - File::FILE_ERROR_ACCESS_DENIED if this root is read-only.
   void DeleteFile(const base::FilePath& path, StatusCallback callback);
 
   // Creates a file at the given path.
@@ -93,6 +96,7 @@ class ArcDocumentsProviderRoot : public ArcFileSystemOperationRunner::Observer {
   // This reports following error code via |callback|:
   // - File::FILE_ERROR_NOT_FOUND if |path|'s parent directory does not exist.
   // - File::FILE_ERROR_EXISTS if a file already exists at |path|.
+  // - File::FILE_ERROR_ACCESS_DENIED if this root is read-only.
   void CreateFile(const base::FilePath& path, StatusCallback callback);
 
   // Creates a directory at the given path.
@@ -100,6 +104,7 @@ class ArcDocumentsProviderRoot : public ArcFileSystemOperationRunner::Observer {
   // This reports following error code via |callback|:
   // - File::FILE_ERROR_NOT_FOUND if |path|'s parent directory does not exist.
   // - File::FILE_ERROR_EXISTS if a file already exists at |path|.
+  // - File::FILE_ERROR_ACCESS_DENIED if this root is read-only.
   void CreateDirectory(const base::FilePath& path, StatusCallback callback);
 
   // Copies a file from |src_path| to |dest_path| inside this root.
@@ -107,6 +112,7 @@ class ArcDocumentsProviderRoot : public ArcFileSystemOperationRunner::Observer {
   // This reports following error code via |callback|:
   // - File::FILE_ERROR_NOT_FOUND if |src_path| or the parent directory of
   //   |dest_path| does not exist.
+  // - File::FILE_ERROR_ACCESS_DENIED if this root is read-only.
   void CopyFileLocal(const base::FilePath& src_path,
                      const base::FilePath& dest_path,
                      StatusCallback callback);
@@ -116,6 +122,7 @@ class ArcDocumentsProviderRoot : public ArcFileSystemOperationRunner::Observer {
   // This reports following error code via |callback|:
   // - File::FILE_ERROR_NOT_FOUND if |src_path| or the parent directory of
   //   |dest_path| does not exist.
+  // - File::FILE_ERROR_ACCESS_DENIED if this root is read-only.
   void MoveFileLocal(const base::FilePath& src_path,
                      const base::FilePath& dest_path,
                      StatusCallback callback);

chrome/browser/chromeos/arc/fileapi/arc_documents_provider_root_unittest.cc

@@ -186,6 +186,10 @@ class ArcDocumentsProviderRootTest : public testing::Test {
         ArcFileSystemOperationRunner::GetForBrowserContext(profile_.get()),
         kAuthority, kRootSpec.document_id, "", false,
         std::vector<std::string>());
+    read_only_root_ = std::make_unique<ArcDocumentsProviderRoot>(
+        ArcFileSystemOperationRunner::GetForBrowserContext(profile_.get()),
+        kAuthority, kRootSpec.document_id, "read-only", true,
+        std::vector<std::string>());
   }
 
   void TearDown() override {
@@ -206,6 +210,7 @@ class ArcDocumentsProviderRootTest : public testing::Test {
   std::unique_ptr<ArcServiceManager> arc_service_manager_;
   std::unique_ptr<TestingProfile> profile_;
   std::unique_ptr<ArcDocumentsProviderRoot> root_;
+  std::unique_ptr<ArcDocumentsProviderRoot> read_only_root_;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(ArcDocumentsProviderRootTest);
@@ -639,6 +644,25 @@ TEST_F(ArcDocumentsProviderRootTest, DeleteDirectory) {
       base::FilePath(FILE_PATH_LITERAL("dir"))));
 }
 
+TEST_F(ArcDocumentsProviderRootTest, DeleteFileOnReadOnlyRoot) {
+  base::RunLoop run_loop;
+  read_only_root_->DeleteFile(
+      base::FilePath(FILE_PATH_LITERAL("dir/photo.jpg")),
+      base::BindOnce(
+          [](base::RunLoop* run_loop, base::File::Error error) {
+            run_loop->Quit();
+            // An attempt to delete a file on read-only root
+            // should return FILE_ERROR_ACCESS_DENIED error.
+            EXPECT_EQ(base::File::FILE_ERROR_ACCESS_DENIED, error);
+          },
+          &run_loop));
+  run_loop.Run();
+  // dir/photo.jpg should not have been removed.
+  EXPECT_TRUE(fake_file_system_.DocumentExists(
+      kAuthority, kRootSpec.document_id,
+      base::FilePath(FILE_PATH_LITERAL("dir/photo.jpg"))));
+}
+
 TEST_F(ArcDocumentsProviderRootTest, CreateFile) {
   // Make sure that dir/new.txt doesn't exist.
   ASSERT_FALSE(fake_file_system_.DocumentExists(
@@ -751,6 +775,25 @@ TEST_F(ArcDocumentsProviderRootTest, CreateFileInReadOnlyDirectory) {
       base::FilePath(FILE_PATH_LITERAL("dir3/photo.jpg"))));
 }
 
+TEST_F(ArcDocumentsProviderRootTest, CreateFileOnReadOnlyRoot) {
+  base::RunLoop run_loop;
+  read_only_root_->CreateFile(
+      base::FilePath(FILE_PATH_LITERAL("dir/new.txt")),
+      base::BindOnce(
+          [](base::RunLoop* run_loop, base::File::Error error) {
+            run_loop->Quit();
+            // An attempt to create a file on read-only root should return
+            // FILE_ERROR_ACCESS_DENIED error.
+            EXPECT_EQ(base::File::FILE_ERROR_ACCESS_DENIED, error);
+          },
+          &run_loop));
+  run_loop.Run();
+  // The dir/new.txt should not have been created.
+  EXPECT_FALSE(fake_file_system_.DocumentExists(
+      kAuthority, kRootSpec.document_id,
+      base::FilePath(FILE_PATH_LITERAL("dir/new.txt"))));
+}
+
 TEST_F(ArcDocumentsProviderRootTest, CreateDirectory) {
   // Make sure that directory "dir2" doesn't exist.
   ASSERT_FALSE(fake_file_system_.DocumentExists(
@@ -821,6 +864,25 @@ TEST_F(ArcDocumentsProviderRootTest, CreateDirectoryParentNotFound) {
       base::FilePath(FILE_PATH_LITERAL("dir3/new_dir"))));
 }
 
+TEST_F(ArcDocumentsProviderRootTest, CreateDirectoryOnReadOnlyRoot) {
+  base::RunLoop run_loop;
+  read_only_root_->CreateDirectory(
+      base::FilePath(FILE_PATH_LITERAL("dir2")),
+      base::BindOnce(
+          [](base::RunLoop* run_loop, base::File::Error error) {
+            run_loop->Quit();
+            // An attempt to create a directory on read-only root should return
+            // FILE_ERROR_ACCESS_DENIED error.
+            EXPECT_EQ(base::File::FILE_ERROR_ACCESS_DENIED, error);
+          },
+          &run_loop));
+  run_loop.Run();
+  // The dir2 should not have been created.
+  EXPECT_FALSE(fake_file_system_.DocumentExists(
+      kAuthority, kRootSpec.document_id,
+      base::FilePath(FILE_PATH_LITERAL("dir2"))));
+}
+
 TEST_F(ArcDocumentsProviderRootTest, CopyFile) {
   base::RunLoop run_loop;
   root_->CopyFileLocal(
@@ -893,6 +955,30 @@ TEST_F(ArcDocumentsProviderRootTest, CopyFileDestParentNotFound) {
   run_loop.Run();
 }
 
+TEST_F(ArcDocumentsProviderRootTest, CopyFileOnReadOnlyRoot) {
+  base::RunLoop run_loop;
+  read_only_root_->CopyFileLocal(
+      base::FilePath(FILE_PATH_LITERAL("dir/photo.jpg")),
+      base::FilePath(FILE_PATH_LITERAL("dir/photo2.jpg")),
+      base::BindOnce(
+          [](base::RunLoop* run_loop, base::File::Error error) {
+            run_loop->Quit();
+            // An attempt to copy a directory on read-only root should return
+            // FILE_ERROR_ACCESS_DENIED error.
+            EXPECT_EQ(base::File::FILE_ERROR_ACCESS_DENIED, error);
+          },
+          &run_loop));
+  run_loop.Run();
+  // dir/photo2.jpg should not be created by the copy.
+  EXPECT_FALSE(fake_file_system_.DocumentExists(
+      kAuthority, kRootSpec.document_id,
+      base::FilePath(FILE_PATH_LITERAL("dir/photo2.jpg"))));
+  // The source file should still be there.
+  EXPECT_TRUE(fake_file_system_.DocumentExists(
+      kAuthority, kRootSpec.document_id,
+      base::FilePath(FILE_PATH_LITERAL("dir/photo.jpg"))));
+}
+
 TEST_F(ArcDocumentsProviderRootTest, RenameFile) {
   base::RunLoop run_loop;
   root_->MoveFileLocal(
@@ -948,6 +1034,30 @@ TEST_F(ArcDocumentsProviderRootTest, RenameFileNotRenamable) {
       base::FilePath(FILE_PATH_LITERAL("dir/no-rename2.jpg"))));
 }
 
+TEST_F(ArcDocumentsProviderRootTest, RenameFileOnReadOnlyRoot) {
+  base::RunLoop run_loop;
+  read_only_root_->MoveFileLocal(
+      base::FilePath(FILE_PATH_LITERAL("dir/photo.jpg")),
+      base::FilePath(FILE_PATH_LITERAL("dir/photo2.jpg")),
+      base::BindOnce(
+          [](base::RunLoop* run_loop, base::File::Error error) {
+            run_loop->Quit();
+            // An attempt to rename a file on read-only root should return
+            // FILE_ERROR_ACCESS_DENIED error.
+            EXPECT_EQ(base::File::FILE_ERROR_ACCESS_DENIED, error);
+          },
+          &run_loop));
+  run_loop.Run();
+  // dir/no-rename.jpg should still be there.
+  EXPECT_TRUE(fake_file_system_.DocumentExists(
+      kAuthority, kRootSpec.document_id,
+      base::FilePath(FILE_PATH_LITERAL("dir/no-rename.jpg"))));
+  // dir/no-rename2.jpg shouldn't be there".
+  EXPECT_FALSE(fake_file_system_.DocumentExists(
+      kAuthority, kRootSpec.document_id,
+      base::FilePath(FILE_PATH_LITERAL("dir/no-rename2.jpg"))));
+}
+
 TEST_F(ArcDocumentsProviderRootTest, MoveFile) {
   base::RunLoop run_loop;
   root_->MoveFileLocal(
@@ -1032,6 +1142,30 @@ TEST_F(ArcDocumentsProviderRootTest, MoveFileDestParentNotFound) {
   run_loop.Run();
 }
 
+TEST_F(ArcDocumentsProviderRootTest, MoveFileOnReadOnlyRoot) {
+  base::RunLoop run_loop;
+  read_only_root_->MoveFileLocal(
+      base::FilePath(FILE_PATH_LITERAL("dir/photo.jpg")),
+      base::FilePath(FILE_PATH_LITERAL("photo.jpg")),
+      base::BindOnce(
+          [](base::RunLoop* run_loop, base::File::Error error) {
+            run_loop->Quit();
+            // An attempt to move a file on read-only root should return
+            // FILE_ERROR_ACCESS_DENIED error.
+            EXPECT_EQ(base::File::FILE_ERROR_ACCESS_DENIED, error);
+          },
+          &run_loop));
+  run_loop.Run();
+  // The destination file should not be created.
+  EXPECT_FALSE(fake_file_system_.DocumentExists(
+      kAuthority, kRootSpec.document_id,
+      base::FilePath(FILE_PATH_LITERAL("photo.jpg"))));
+  // The source file should not be gone by move.
+  EXPECT_TRUE(fake_file_system_.DocumentExists(
+      kAuthority, kRootSpec.document_id,
+      base::FilePath(FILE_PATH_LITERAL("dir/photo.jpg"))));
+}
+
 TEST_F(ArcDocumentsProviderRootTest, WatchChanged) {
   int num_called = 0;
   auto watcher_callback = base::Bind(