[Downloads] Retry renames after transient failures.

content/browser/download/base_file_unittest.cc

 // Copyright (c) 2012 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 "content/browser/download/base_file.h"
 
 #include "base/file_util.h"
 #include "base/files/file.h"
 #include "base/files/scoped_temp_dir.h"
 #include "base/logging.h"
@@ skipping 458 matching lines @@
   {
     file_util::PermissionRestorer restore_permissions_for(test_dir);
     ASSERT_TRUE(file_util::MakeFileUnwritable(test_dir));
     EXPECT_EQ(DOWNLOAD_INTERRUPT_REASON_FILE_ACCESS_DENIED,
               base_file_->Rename(new_path));
   }
 
   base_file_->Finish();
 }
 
+// Test that if a rename fails for an in-progress BaseFile, it remains writeable
+// and renameable.
+TEST_F(BaseFileTest, RenameWithErrorInProgress) {
+  ASSERT_TRUE(InitializeFile());
+
+  base::FilePath test_dir(temp_dir_.path().AppendASCII("TestDir"));
+  ASSERT_TRUE(base::CreateDirectory(test_dir));
+
+  base::FilePath new_path(test_dir.AppendASCII("TestFile"));
+  EXPECT_FALSE(base::PathExists(new_path));
+
+  // Write some data to start with.
+  ASSERT_TRUE(AppendDataToFile(kTestData1));
+  ASSERT_TRUE(base_file_->in_progress());
+
+  base::FilePath old_path = base_file_->full_path();
+
+  {
+    file_util::PermissionRestorer restore_permissions_for(test_dir);
+    ASSERT_TRUE(file_util::MakeFileUnwritable(test_dir));
+    EXPECT_EQ(DOWNLOAD_INTERRUPT_REASON_FILE_ACCESS_DENIED,
+              base_file_->Rename(new_path));
+
+    // The file should still be open and we should be able to continue writing
+    // to it.
+    ASSERT_TRUE(base_file_->in_progress());
+    ASSERT_TRUE(AppendDataToFile(kTestData2));
+    ASSERT_EQ(old_path.value(), base_file_->full_path().value());
+
+    // Try to rename again, just for kicks. It should still fail with
+    // ACCESS_DENIED.
+    EXPECT_EQ(DOWNLOAD_INTERRUPT_REASON_FILE_ACCESS_DENIED,
+              base_file_->Rename(new_path));
+  }
+
+  // Now that TestDir is writeable again, we should be able to successfully
+  // rename the file.
+  EXPECT_EQ(DOWNLOAD_INTERRUPT_REASON_NONE, base_file_->Rename(new_path));
+  ASSERT_EQ(new_path.value(), base_file_->full_path().value());
+  ASSERT_TRUE(AppendDataToFile(kTestData3));
+
+  base_file_->Finish();
+
+  // The contents of the file should be intact.
+  std::string file_contents;
+  std::string expected_contents(kTestData1);
+  expected_contents += kTestData2;
+  expected_contents += kTestData3;
+  ASSERT_TRUE(base::ReadFileToString(new_path, &file_contents));
+  EXPECT_EQ(expected_contents, file_contents);
+}
+

[Randy Smith (Not in Mondays), 2014/06/12 22:10:30]

Should you also test the case where the rename succeed and the open failed? 
(Note: I don't offhand think of a way to do that, and if you can't either, don't
worry about it.)

[asanka, 2014/06/17 21:40:56]

I was thinking something along the lines of using dropbox ACLs (allow insert,
but not write, thus allowing a caller of create() to write() until close() but
then subsequent opens fail). But it's too file system dependent.

I think I'll let this one slide.

 // Test that a failed write reports an error.
 TEST_F(BaseFileTest, WriteWithError) {
   base::FilePath path;
   ASSERT_TRUE(base::CreateTemporaryFile(&path));
 
   // Pass a file handle which was opened without the WRITE flag.
   // This should result in an error when writing.
   base::File file(path, base::File::FLAG_OPEN_ALWAYS | base::File::FLAG_READ);
   base_file_.reset(new BaseFile(path,
                                 GURL(),
@@ skipping 141 matching lines @@
 
   const char kData[] = "hello";
   const int kDataLength = static_cast<int>(arraysize(kData) - 1);
   ASSERT_EQ(kDataLength, base::WriteFile(full_path, kData, kDataLength));
   // The file that we created here should stick around when the BaseFile is
   // destroyed during TearDown.
   expect_file_survives_ = true;
 }
 
 }  // namespace content