[fsp] Do not allow write operations on read only file systems.

chrome/browser/chromeos/file_system_provider/operations/open_file_unittest.cc

 // Copyright 2014 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/chromeos/file_system_provider/operations/open_file.h"
 
 #include <string>
 #include <vector>
 
 #include "base/files/file.h"
@@ skipping 129 matching lines @@
                      ProvidedFileSystemInterface::OPEN_FILE_MODE_READ,
                      base::Bind(&CallbackLogger::OnOpenFile,
                                 base::Unretained(&callback_logger)));
   open_file.SetDispatchEventImplForTesting(
       base::Bind(&util::LoggingDispatchEventImpl::OnDispatchEventImpl,
                  base::Unretained(&dispatcher)));
 
   EXPECT_FALSE(open_file.Execute(kRequestId));
 }
 
+TEST_F(FileSystemProviderOperationsOpenFileTest, Execute_ReadOnly) {
+  util::LoggingDispatchEventImpl dispatcher(true /* dispatch_reply */);
+  CallbackLogger callback_logger;
+
+  const ProvidedFileSystemInfo read_only_file_system_info(
+      kExtensionId,
+      kFileSystemId,
+      "" /* file_system_name */,
+      false /* writable */,
+      base::FilePath() /* mount_path */);
+
+  // Opening for read on a read-only file system is allowed.
+  {
+    OpenFile open_file(NULL,
+                       read_only_file_system_info,
+                       base::FilePath::FromUTF8Unsafe(kFilePath),
+                       ProvidedFileSystemInterface::OPEN_FILE_MODE_READ,
+                       base::Bind(&CallbackLogger::OnOpenFile,
+                                  base::Unretained(&callback_logger)));
+    open_file.SetDispatchEventImplForTesting(
+        base::Bind(&util::LoggingDispatchEventImpl::OnDispatchEventImpl,
+                   base::Unretained(&dispatcher)));
+
+    EXPECT_TRUE(open_file.Execute(kRequestId));
+  }
+
+  // Opening for write on a read-only file system is forbidden and must fail.
+  {
+    OpenFile open_file(NULL,
+                       read_only_file_system_info,
+                       base::FilePath::FromUTF8Unsafe(kFilePath),
+                       ProvidedFileSystemInterface::OPEN_FILE_MODE_WRITE,
+                       base::Bind(&CallbackLogger::OnOpenFile,
+                                  base::Unretained(&callback_logger)));
+    open_file.SetDispatchEventImplForTesting(
+        base::Bind(&util::LoggingDispatchEventImpl::OnDispatchEventImpl,
+                   base::Unretained(&dispatcher)));
+
+    EXPECT_FALSE(open_file.Execute(kRequestId));
+  }
+}
+
 TEST_F(FileSystemProviderOperationsOpenFileTest, OnSuccess) {
   util::LoggingDispatchEventImpl dispatcher(true /* dispatch_reply */);
   CallbackLogger callback_logger;
 
   OpenFile open_file(NULL,
                      file_system_info_,
                      base::FilePath::FromUTF8Unsafe(kFilePath),
                      ProvidedFileSystemInterface::OPEN_FILE_MODE_READ,
                      base::Bind(&CallbackLogger::OnOpenFile,
                                 base::Unretained(&callback_logger)));
@@ skipping 33 matching lines @@
                     base::File::FILE_ERROR_TOO_MANY_OPENED);
   ASSERT_EQ(1u, callback_logger.events().size());
   CallbackLogger::Event* event = callback_logger.events()[0];
   EXPECT_EQ(base::File::FILE_ERROR_TOO_MANY_OPENED, event->result());
   ASSERT_EQ(0, event->file_handle());
 }
 
 }  // namespace operations
 }  // namespace file_system_provider
 }  // namespace chromeos