Refactor BaseFile class to support sparse files

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 <stddef.h>
 #include <stdint.h>
 #include <utility>
 
@@ skipping 70 matching lines @@
     // Make sure the mock BrowserThread outlives the BaseFile to satisfy
     // thread checks inside it.
     base_file_.reset();
 
     EXPECT_EQ(expect_file_survives_, base::PathExists(full_path));
   }
 
   bool InitializeFile() {
     DownloadInterruptReason result = base_file_->Initialize(
         base::FilePath(), temp_dir_.GetPath(), base::File(), 0, std::string(),
-        std::unique_ptr<crypto::SecureHash>());
+        std::unique_ptr<crypto::SecureHash>(), BaseFile::EXCLUSIVE);
     EXPECT_EQ(expected_error_, result);
     return result == DOWNLOAD_INTERRUPT_REASON_NONE;
   }
 
   bool AppendDataToFile(const std::string& data) {
     EXPECT_EQ(expect_in_progress_, base_file_->in_progress());
     DownloadInterruptReason result =
         base_file_->AppendDataToFile(data.data(), data.size());
     if (result == DOWNLOAD_INTERRUPT_REASON_NONE)
       EXPECT_TRUE(expect_in_progress_) << " result = " << result;
@@ skipping 13 matching lines @@
 
   // Helper functions.
   // Create a file.  Returns the complete file path.
   base::FilePath CreateTestFile() {
     base::FilePath file_name;
     BaseFile file((net::NetLogWithSource()));
 
     EXPECT_EQ(
         DOWNLOAD_INTERRUPT_REASON_NONE,
         file.Initialize(base::FilePath(), temp_dir_.GetPath(), base::File(), 0,
-                        std::string(), std::unique_ptr<crypto::SecureHash>()));
+                        std::string(), std::unique_ptr<crypto::SecureHash>(),
+                        BaseFile::EXCLUSIVE));
     file_name = file.full_path();
     EXPECT_NE(base::FilePath::StringType(), file_name.value());
 
     EXPECT_EQ(DOWNLOAD_INTERRUPT_REASON_NONE,
               file.AppendDataToFile(kTestData4, kTestDataLength4));
 
     // Keep the file from getting deleted when existing_file_name is deleted.
     file.Detach();
 
     return file_name;
   }
 
   // Create a file with the specified file name.
   void CreateFileWithName(const base::FilePath& file_name) {
     EXPECT_NE(base::FilePath::StringType(), file_name.value());
     BaseFile duplicate_file((net::NetLogWithSource()));
     EXPECT_EQ(DOWNLOAD_INTERRUPT_REASON_NONE,
               duplicate_file.Initialize(file_name, temp_dir_.GetPath(),
                                         base::File(), 0, std::string(),
-                                        std::unique_ptr<crypto::SecureHash>()));
+                                        std::unique_ptr<crypto::SecureHash>(),
+                                        BaseFile::EXCLUSIVE));
     // Write something into it.
     duplicate_file.AppendDataToFile(kTestData4, kTestDataLength4);
     // Detach the file so it isn't deleted on destruction of |duplicate_file|.
     duplicate_file.Detach();
   }
 
   int64_t CurrentSpeedAtTime(base::TimeTicks current_time) {
     EXPECT_TRUE(base_file_.get());
     return base_file_->CurrentSpeedAtTime(current_time);
   }
@@ skipping 133 matching lines @@
   ASSERT_TRUE(base::CopyFile(base_file_->full_path(), new_file_path));
 
   // Create another file
   BaseFile second_file((net::NetLogWithSource()));
   ASSERT_EQ(DOWNLOAD_INTERRUPT_REASON_NONE,
             second_file.Initialize(new_file_path,
                                    base::FilePath(),
                                    base::File(),
                                    base_file_->bytes_so_far(),
                                    std::string(),
-                                   std::move(hash_state)));
+                                   std::move(hash_state),
+                                   BaseFile::EXCLUSIVE));
   std::string data(kTestData3);
   EXPECT_EQ(DOWNLOAD_INTERRUPT_REASON_NONE,
             second_file.AppendDataToFile(data.data(), data.size()));
   ExpectHashValue(kHashOfTestData1To3, second_file.Finish());
 }
 
 // Rename the file after all writes to it.
 TEST_F(BaseFileTest, WriteThenRename) {
   ASSERT_TRUE(InitializeFile());
 
@@ skipping 101 matching lines @@
   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(net::NetLogWithSource()));
   EXPECT_EQ(DOWNLOAD_INTERRUPT_REASON_NONE,
             base_file_->Initialize(path, base::FilePath(), std::move(file), 0,
                                    std::string(),
-                                   std::unique_ptr<crypto::SecureHash>()));
+                                   std::unique_ptr<crypto::SecureHash>(),
+                                   BaseFile::EXCLUSIVE));
 #if defined(OS_WIN)
   set_expected_error(DOWNLOAD_INTERRUPT_REASON_FILE_ACCESS_DENIED);
 #elif defined (OS_POSIX)
   set_expected_error(DOWNLOAD_INTERRUPT_REASON_FILE_FAILED);
 #endif
   ASSERT_FALSE(AppendDataToFile(kTestData1));
   base_file_->Finish();
 }
 
 // Try to write to uninitialized file.
@@ skipping 21 matching lines @@
   // Create a new file.
   base::FilePath existing_file_name = CreateTestFile();
   set_expected_data(kTestData4);
 
   // Use the file we've just created.
   base_file_.reset(new BaseFile(net::NetLogWithSource()));
   ASSERT_EQ(
       DOWNLOAD_INTERRUPT_REASON_NONE,
       base_file_->Initialize(existing_file_name, base::FilePath(), base::File(),
                              kTestDataLength4, std::string(),
-                             std::unique_ptr<crypto::SecureHash>()));
+                             std::unique_ptr<crypto::SecureHash>(),
+                             BaseFile::EXCLUSIVE));
 
   const base::FilePath file_name = base_file_->full_path();
   EXPECT_NE(base::FilePath::StringType(), file_name.value());
 
   // Write into the file.
   EXPECT_TRUE(AppendDataToFile(kTestData1));
 
   base_file_->Finish();
   base_file_->Detach();
   expect_file_survives_ = true;
 }
 
 // Create a read-only file and attempt to write to it.
 TEST_F(BaseFileTest, ReadonlyBaseFile) {
   // Create a new file.
   base::FilePath readonly_file_name = CreateTestFile();
 
   // Restore permissions to the file when we are done with this test.
   base::FilePermissionRestorer restore_permissions(readonly_file_name);
 
   // Make it read-only.
   EXPECT_TRUE(base::MakeFileUnwritable(readonly_file_name));
 
   // Try to overwrite it.
   base_file_.reset(new BaseFile(net::NetLogWithSource()));
   EXPECT_EQ(DOWNLOAD_INTERRUPT_REASON_FILE_ACCESS_DENIED,
             base_file_->Initialize(readonly_file_name, base::FilePath(),
                                    base::File(), 0, std::string(),
-                                   std::unique_ptr<crypto::SecureHash>()));
+                                   std::unique_ptr<crypto::SecureHash>(),
+                                   BaseFile::EXCLUSIVE));
 
   expect_in_progress_ = false;
 
   const base::FilePath file_name = base_file_->full_path();
   EXPECT_NE(base::FilePath::StringType(), file_name.value());
 
   // Write into the file.
   set_expected_error(DOWNLOAD_INTERRUPT_REASON_FILE_FAILED);
   EXPECT_FALSE(AppendDataToFile(kTestData1));
 
   base_file_->Finish();
   base_file_->Detach();
   expect_file_survives_ = true;
 }
 
 // Open an existing file and continue writing to it. The hash of the partial
 // file is known and matches the existing contents.
 TEST_F(BaseFileTest, ExistingBaseFileKnownHash) {
   base::FilePath file_path = temp_dir_.GetPath().AppendASCII("existing");
   ASSERT_EQ(kTestDataLength1,
             base::WriteFile(file_path, kTestData1, kTestDataLength1));
 
   std::string hash_so_far(std::begin(kHashOfTestData1),
                           std::end(kHashOfTestData1));
   EXPECT_EQ(DOWNLOAD_INTERRUPT_REASON_NONE,
             base_file_->Initialize(file_path, base::FilePath(), base::File(),
                                    kTestDataLength1, hash_so_far,
-                                   std::unique_ptr<crypto::SecureHash>()));
+                                   std::unique_ptr<crypto::SecureHash>(),
+                                   BaseFile::EXCLUSIVE));
   set_expected_data(kTestData1);
   ASSERT_TRUE(AppendDataToFile(kTestData2));
   ASSERT_TRUE(AppendDataToFile(kTestData3));
   ExpectHashValue(kHashOfTestData1To3, base_file_->Finish());
 }
 
 // Open an existing file and continue writing to it. The hash of the partial
 // file is unknown.
 TEST_F(BaseFileTest, ExistingBaseFileUnknownHash) {
   base::FilePath file_path = temp_dir_.GetPath().AppendASCII("existing");
   ASSERT_EQ(kTestDataLength1,
             base::WriteFile(file_path, kTestData1, kTestDataLength1));
 
   EXPECT_EQ(DOWNLOAD_INTERRUPT_REASON_NONE,
             base_file_->Initialize(file_path, base::FilePath(), base::File(),
                                    kTestDataLength1, std::string(),
-                                   std::unique_ptr<crypto::SecureHash>()));
+                                   std::unique_ptr<crypto::SecureHash>(),
+                                   BaseFile::EXCLUSIVE));
   set_expected_data(kTestData1);
   ASSERT_TRUE(AppendDataToFile(kTestData2));
   ASSERT_TRUE(AppendDataToFile(kTestData3));
   ExpectHashValue(kHashOfTestData1To3, base_file_->Finish());
 }
 
 // Open an existing file. The contentsof the file doesn't match the known hash.
 TEST_F(BaseFileTest, ExistingBaseFileIncorrectHash) {
   base::FilePath file_path = temp_dir_.GetPath().AppendASCII("existing");
   ASSERT_EQ(kTestDataLength2,
             base::WriteFile(file_path, kTestData2, kTestDataLength2));
 
   std::string hash_so_far(std::begin(kHashOfTestData1),
                           std::end(kHashOfTestData1));
   EXPECT_EQ(DOWNLOAD_INTERRUPT_REASON_FILE_HASH_MISMATCH,
             base_file_->Initialize(file_path, base::FilePath(), base::File(),
                                    kTestDataLength2, hash_so_far,
-                                   std::unique_ptr<crypto::SecureHash>()));
+                                   std::unique_ptr<crypto::SecureHash>(),
+                                   BaseFile::EXCLUSIVE));
   set_expected_error(DOWNLOAD_INTERRUPT_REASON_FILE_HASH_MISMATCH);
 }
 
 // Open a large existing file with a known hash and continue writing to it.
 TEST_F(BaseFileTest, ExistingBaseFileLargeSizeKnownHash) {
   base::FilePath file_path = temp_dir_.GetPath().AppendASCII("existing");
   std::string big_buffer(1024 * 200, 'a');
   ASSERT_EQ(static_cast<int>(big_buffer.size()),
             base::WriteFile(file_path, big_buffer.data(), big_buffer.size()));
 
   // Hash of partial file (1024*200 * 'a')
   const uint8_t kExpectedPartialHash[] = {
       0x4b, 0x4f, 0x0f, 0x46, 0xac, 0x02, 0xd1, 0x77, 0xde, 0xa0, 0xab,
       0x36, 0xa6, 0x6a, 0x65, 0x78, 0x40, 0xe2, 0xfb, 0x98, 0xb2, 0x0b,
       0xb2, 0x7a, 0x68, 0x8d, 0xb4, 0xd8, 0xea, 0x9c, 0xd2, 0x2c};
 
   // Hash of entire file (1024*400 * 'a')
   const uint8_t kExpectedFullHash[] = {
       0x0c, 0xe9, 0xf6, 0x78, 0x6b, 0x0f, 0x58, 0x49, 0x36, 0xe8, 0x83,
       0xc5, 0x09, 0x16, 0xbc, 0x5e, 0x2d, 0x07, 0x95, 0xb9, 0x42, 0x20,
       0x41, 0x7c, 0xb3, 0x38, 0xd3, 0xf4, 0xe0, 0x78, 0x89, 0x46};
 
   ASSERT_EQ(DOWNLOAD_INTERRUPT_REASON_NONE,
             base_file_->Initialize(file_path, base::FilePath(), base::File(),
                                    big_buffer.size(),
                                    std::string(std::begin(kExpectedPartialHash),
                                                std::end(kExpectedPartialHash)),
-                                   std::unique_ptr<crypto::SecureHash>()));
+                                   std::unique_ptr<crypto::SecureHash>(),
+                                   BaseFile::EXCLUSIVE));
   set_expected_data(big_buffer);  // Contents of the file on Open.
   ASSERT_TRUE(AppendDataToFile(big_buffer));
   ExpectHashValue(kExpectedFullHash, base_file_->Finish());
 }
 
 // Open a large existing file. The contents doesn't match the known hash.
 TEST_F(BaseFileTest, ExistingBaseFileLargeSizeIncorrectHash) {
   base::FilePath file_path = temp_dir_.GetPath().AppendASCII("existing");
   std::string big_buffer(1024 * 200, 'a');
   ASSERT_EQ(static_cast<int>(big_buffer.size()),
             base::WriteFile(file_path, big_buffer.data(), big_buffer.size()));
 
   // Incorrect hash of partial file (1024*200 * 'a')
   const uint8_t kExpectedPartialHash[] = {
       0xc2, 0xa9, 0x08, 0xd9, 0x8f, 0x5d, 0xf9, 0x87, 0xad, 0xe4, 0x1b,
       0x5f, 0xce, 0x21, 0x30, 0x67, 0xef, 0x6c, 0xc2, 0x1e, 0xf2, 0x24,
       0x02, 0x12, 0xa4, 0x1e, 0x54, 0xb5, 0xe7, 0xc2, 0x8a, 0xe5};
 
   EXPECT_EQ(DOWNLOAD_INTERRUPT_REASON_FILE_HASH_MISMATCH,
             base_file_->Initialize(file_path, base::FilePath(), base::File(),
                                    big_buffer.size(),
                                    std::string(std::begin(kExpectedPartialHash),
                                                std::end(kExpectedPartialHash)),
-                                   std::unique_ptr<crypto::SecureHash>()));
+                                   std::unique_ptr<crypto::SecureHash>(),
+                                   BaseFile::EXCLUSIVE));
   set_expected_error(DOWNLOAD_INTERRUPT_REASON_FILE_HASH_MISMATCH);
 }
 
 // Open an existing file. The size of the file is too short.
 TEST_F(BaseFileTest, ExistingBaseFileTooShort) {
   base::FilePath file_path = temp_dir_.GetPath().AppendASCII("existing");
   ASSERT_EQ(kTestDataLength1,
             base::WriteFile(file_path, kTestData1, kTestDataLength1));
 
   EXPECT_EQ(DOWNLOAD_INTERRUPT_REASON_FILE_TOO_SHORT,
             base_file_->Initialize(file_path, base::FilePath(), base::File(),
                                    kTestDataLength1 + 1, std::string(),
-                                   std::unique_ptr<crypto::SecureHash>()));
+                                   std::unique_ptr<crypto::SecureHash>(),
+                                   BaseFile::EXCLUSIVE));
   set_expected_error(DOWNLOAD_INTERRUPT_REASON_FILE_TOO_SHORT);
 }
 
 // Open an existing file. The size is larger than expected.
 TEST_F(BaseFileTest, ExistingBaseFileKnownHashTooLong) {
   base::FilePath file_path = temp_dir_.GetPath().AppendASCII("existing");
   std::string contents;
   contents.append(kTestData1);
   contents.append("Something extra");
   ASSERT_EQ(static_cast<int>(contents.size()),
             base::WriteFile(file_path, contents.data(), contents.size()));
 
   std::string hash_so_far(std::begin(kHashOfTestData1),
                           std::end(kHashOfTestData1));
   EXPECT_EQ(DOWNLOAD_INTERRUPT_REASON_NONE,
             base_file_->Initialize(file_path, base::FilePath(), base::File(),
                                    kTestDataLength1, hash_so_far,
-                                   std::unique_ptr<crypto::SecureHash>()));
+                                   std::unique_ptr<crypto::SecureHash>(),
+                                   BaseFile::EXCLUSIVE));
   set_expected_data(kTestData1);  // Our starting position.
   ASSERT_TRUE(AppendDataToFile(kTestData2));
   ASSERT_TRUE(AppendDataToFile(kTestData3));
   ExpectHashValue(kHashOfTestData1To3, base_file_->Finish());
 }
 
 // Open an existing file. The size is large than expected and the hash is
 // unknown.
 TEST_F(BaseFileTest, ExistingBaseFileUnknownHashTooLong) {
   base::FilePath file_path = temp_dir_.GetPath().AppendASCII("existing");
   std::string contents;
   contents.append(kTestData1);
   contents.append("Something extra");
   ASSERT_EQ(static_cast<int>(contents.size()),
             base::WriteFile(file_path, contents.data(), contents.size()));
 
   EXPECT_EQ(DOWNLOAD_INTERRUPT_REASON_NONE,
             base_file_->Initialize(file_path, base::FilePath(), base::File(),
                                    kTestDataLength1, std::string(),
-                                   std::unique_ptr<crypto::SecureHash>()));
+                                   std::unique_ptr<crypto::SecureHash>(),
+                                   BaseFile::EXCLUSIVE));
   set_expected_data(kTestData1);
   ASSERT_TRUE(AppendDataToFile(kTestData2));
   ASSERT_TRUE(AppendDataToFile(kTestData3));
   ExpectHashValue(kHashOfTestData1To3, base_file_->Finish());
 }
 
 // Similar to ExistingBaseFileKnownHashTooLong test, but with a file large
 // enough to requre multiple Read()s to complete. This provides additional code
 // coverage for the CalculatePartialHash() logic.
 TEST_F(BaseFileTest, ExistingBaseFileUnknownHashTooLongForLargeFile) {
   base::FilePath file_path = temp_dir_.GetPath().AppendASCII("existing");
   const size_t kFileSize = 1024 * 1024;
   const size_t kIntermediateSize = kFileSize / 2 + 111;
   // |contents| is 100 bytes longer than kIntermediateSize. The latter is the
   // expected size.
   std::string contents(kIntermediateSize + 100, 'a');
   ASSERT_EQ(static_cast<int>(contents.size()),
             base::WriteFile(file_path, contents.data(), contents.size()));
 
   EXPECT_EQ(DOWNLOAD_INTERRUPT_REASON_NONE,
             base_file_->Initialize(file_path, base::FilePath(), base::File(),
                                    kIntermediateSize, std::string(),
-                                   std::unique_ptr<crypto::SecureHash>()));
+                                   std::unique_ptr<crypto::SecureHash>(),
+                                   BaseFile::EXCLUSIVE));
   // The extra bytes should be stripped during Initialize().
   contents.resize(kIntermediateSize, 'a');
   set_expected_data(contents);
   std::string new_data(kFileSize - kIntermediateSize, 'a');
   ASSERT_TRUE(AppendDataToFile(new_data));
   const uint8_t kExpectedHash[] = {
       0x9b, 0xc1, 0xb2, 0xa2, 0x88, 0xb2, 0x6a, 0xf7, 0x25, 0x7a, 0x36,
       0x27, 0x7a, 0xe3, 0x81, 0x6a, 0x7d, 0x4f, 0x16, 0xe8, 0x9c, 0x1e,
       0x7e, 0x77, 0xd0, 0xa5, 0xc4, 0x8b, 0xad, 0x62, 0xb3, 0x60,
   };
@@ skipping 29 matching lines @@
   ASSERT_FALSE(base::PathExists(full_path));
 
   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;
 }
 
+// Test that writing data to a particular offset works.
+TEST_F(BaseFileTest, WriteDataAtOffset) {
+  base::FilePath file_path = temp_dir_.GetPath().AppendASCII("existing");
+  std::string contents = kTestData1;
+  ASSERT_EQ(static_cast<int>(contents.size()),
+            base::WriteFile(file_path, contents.data(), contents.size()));
+
+  base_file_->Initialize(file_path, base::FilePath(), base::File(),
+                         kTestDataLength1,
+                         std::string(),
+                         std::unique_ptr<crypto::SecureHash>(),
+                         BaseFile::SHARED);
+  // This will create a hole in the file.
+  base_file_->WriteDataToFile(kTestDataLength1 + kTestDataLength2,
+                              kTestData4,
+                              kTestDataLength4);
+  // This should fill the hole.
+  base_file_->WriteDataToFile(kTestDataLength1,
+                              kTestData2,
+                              kTestDataLength2);
+  set_expected_data(contents + kTestData2 + kTestData4);
+  base_file_->Finish();
+}
+
 }  // namespace content