[Downloads] BaseFile shouldn't read past the expected EOF for a stub file.

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 499 matching lines @@
 
   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_.path().AppendASCII("existing");
-  ASSERT_TRUE(base::WriteFile(file_path, kTestData1, kTestDataLength1));
+  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>()));
   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_.path().AppendASCII("existing");
-  ASSERT_TRUE(base::WriteFile(file_path, kTestData1, kTestDataLength1));
+  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>()));
   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_.path().AppendASCII("existing");
-  ASSERT_TRUE(base::WriteFile(file_path, kTestData2, kTestDataLength2));
+  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>()));
   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_.path().AppendASCII("existing");
   std::string big_buffer(1024 * 200, 'a');
-  ASSERT_TRUE(base::WriteFile(file_path, big_buffer.data(), big_buffer.size()));
+  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>()));
   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_.path().AppendASCII("existing");
   std::string big_buffer(1024 * 200, 'a');
-  ASSERT_TRUE(base::WriteFile(file_path, big_buffer.data(), big_buffer.size()));
+  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>()));
   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_.path().AppendASCII("existing");
-  ASSERT_TRUE(base::WriteFile(file_path, kTestData1, kTestDataLength1));
+  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>()));
   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_.path().AppendASCII("existing");
   std::string contents;
   contents.append(kTestData1);
   contents.append("Something extra");
-  ASSERT_TRUE(base::WriteFile(file_path, contents.data(), contents.size()));
+  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>()));
   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_.path().AppendASCII("existing");
   std::string contents;
   contents.append(kTestData1);
   contents.append("Something extra");
-  ASSERT_TRUE(base::WriteFile(file_path, contents.data(), contents.size()));
+  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>()));
   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_.path().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>()));
+  // 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,
+  };
+  ExpectHashValue(kExpectedHash, base_file_->Finish());
+}
+
 // Test that a temporary file is created in the default download directory.
 TEST_F(BaseFileTest, CreatedInDefaultDirectory) {
   ASSERT_TRUE(base_file_->full_path().empty());
   ASSERT_TRUE(InitializeFile());
   EXPECT_FALSE(base_file_->full_path().empty());
 
   // On Windows, CreateTemporaryFileInDir() will cause a path with short names
   // to be expanded into a path with long names. Thus temp_dir.path() might not
   // be a string-wise match to base_file_->full_path().DirName() even though
   // they are in the same directory.
@@ skipping 16 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