Add ZipReader::ExtractCurrentEntry with a delegate interface.

This change gives consumers of ZipReader a way to have the current entry
streamed to them via a Delegate interface. It also:

- Reduces duplication in the ExtractCurrentEntry* functions.
- Uses the heap rather than the stack for intermediate buffers.
- Changes ExtractCurrentEntryToFd to ExtractCurrentEntryToFile, making
  it cross-platform in the process.

BUG=462584

Review URL: https://codereview.chromium.org/1014653002

Cr-Commit-Position: refs/heads/master@{#320948}

third_party/zlib/google/zip_reader.h

@@ -23,6 +23,21 @@
 
 namespace zip {
 
+// A delegate interface used to stream out an entry; see
+// ZipReader::ExtractCurrentEntry.
+class WriterDelegate {
+ public:
+  virtual ~WriterDelegate() {}
+
+  // Invoked once before any data is streamed out to pave the way (e.g., to open
+  // the output file). Return false on failure to cancel extraction.
+  virtual bool PrepareOutput() = 0;
+
+  // Invoked to write the next chunk of data. Return false on failure to cancel
+  // extraction.
+  virtual bool WriteBytes(const char* data, int num_bytes) = 0;
+};
+
 // This class is used for reading zip files. A typical use case of this
 // class is to scan entries in a zip file and extract them. The code will
 // look like:
@@ -141,6 +156,9 @@ class ZipReader {
   // success. On failure, current_entry_info() becomes NULL.
   bool LocateAndOpenEntry(const base::FilePath& path_in_zip);
 
+  // Extracts the current entry in chunks to |delegate|.
+  bool ExtractCurrentEntry(WriterDelegate* delegate) const;
+
   // Extracts the current entry to the given output file path. If the
   // current file is a directory, just creates a directory
   // instead. Returns true on success. OpenCurrentEntryInZip() must be
@@ -148,7 +166,8 @@ class ZipReader {
   //
   // This function preserves the timestamp of the original entry. If that
   // timestamp is not valid, the timestamp will be set to the current time.
-  bool ExtractCurrentEntryToFilePath(const base::FilePath& output_file_path);
+  bool ExtractCurrentEntryToFilePath(
+      const base::FilePath& output_file_path) const;
 
   // Asynchronously extracts the current entry to the given output file path.
   // If the current entry is a directory it just creates the directory
@@ -174,13 +193,11 @@ class ZipReader {
   // This function preserves the timestamp of the original entry. If that
   // timestamp is not valid, the timestamp will be set to the current time.
   bool ExtractCurrentEntryIntoDirectory(
-      const base::FilePath& output_directory_path);
+      const base::FilePath& output_directory_path) const;
 
-#if defined(OS_POSIX)
-  // Extracts the current entry by writing directly to a file descriptor.
-  // Does not close the file descriptor. Returns true on success.
-  bool ExtractCurrentEntryToFd(int fd);
-#endif
+  // Extracts the current entry by writing directly to a platform file.
+  // Does not close the file. Returns true on success.
+  bool ExtractCurrentEntryToFile(base::File* file) const;
 
   // Extracts the current entry into memory. If the current entry is a directory
   // the |output| parameter is set to the empty string. If the current entry is
@@ -232,6 +249,30 @@ class ZipReader {
   DISALLOW_COPY_AND_ASSIGN(ZipReader);
 };
 
+// A writer delegate that writes to a given File.
+class FileWriterDelegate : public WriterDelegate {
+ public:
+  explicit FileWriterDelegate(base::File* file);
+
+  // Truncates the file to the number of bytes written.
+  ~FileWriterDelegate() override;
+
+  // WriterDelegate methods:
+
+  // Seeks to the beginning of the file, returning false if the seek fails.
+  bool PrepareOutput() override;
+
+  // Writes |num_bytes| bytes of |data| to the file, returning false on error or
+  // if not all bytes could be written.
+  bool WriteBytes(const char* data, int num_bytes) override;
+
+ private:
+  base::File* file_;
+  int64_t file_length_;
+
+  DISALLOW_COPY_AND_ASSIGN(FileWriterDelegate);
+};
+
 }  // namespace zip
 
 #endif  // THIRD_PARTY_ZLIB_GOOGLE_ZIP_READER_H_

third_party/zlib/google/zip_reader_unittest.cc

@@ -18,10 +18,14 @@
 #include "base/strings/stringprintf.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/time/time.h"
+#include "testing/gmock/include/gmock/gmock.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "testing/platform_test.h"
 #include "third_party/zlib/google/zip_internal.h"
 
+using ::testing::Return;
+using ::testing::_;
+
 namespace {
 
 const static std::string kQuuxExpectedMD5 = "d1ae4ac8a17a0e09317113ab284b57a6";
@@ -47,6 +51,8 @@ class FileWrapper {
 
   base::PlatformFile platform_file() { return file_.GetPlatformFile(); }
 
+  base::File* file() { return &file_; }
+
  private:
   base::File file_;
 };
@@ -93,6 +99,12 @@ class MockUnzipListener : public base::SupportsWeakPtr<MockUnzipListener> {
   int64 current_progress_;
 };
 
+class MockWriterDelegate : public zip::WriterDelegate {
+ public:
+  MOCK_METHOD0(PrepareOutput, bool());
+  MOCK_METHOD2(WriteBytes, bool(const char*, int));
+};
+
 }   // namespace
 
 namespace zip {
@@ -287,8 +299,7 @@ TEST_F(ZipReaderTest, PlatformFileExtractCurrentEntryToFilePath_RegularFile) {
   EXPECT_LT(static_cast<size_t>(internal::kZipBufSize), output.size());
 }
 
-#if defined(OS_POSIX)
-TEST_F(ZipReaderTest, PlatformFileExtractCurrentEntryToFd_RegularFile) {
+TEST_F(ZipReaderTest, PlatformFileExtractCurrentEntryToFile_RegularFile) {
   ZipReader reader;
   FileWrapper zip_fd_wrapper(test_zip_file_, FileWrapper::READ_ONLY);
   ASSERT_TRUE(reader.OpenFromPlatformFile(zip_fd_wrapper.platform_file()));
@@ -296,18 +307,16 @@ TEST_F(ZipReaderTest, PlatformFileExtractCurrentEntryToFd_RegularFile) {
   base::FilePath out_path = test_dir_.AppendASCII("quux.txt");
   FileWrapper out_fd_w(out_path, FileWrapper::READ_WRITE);
   ASSERT_TRUE(reader.LocateAndOpenEntry(target_path));
-  ASSERT_TRUE(reader.ExtractCurrentEntryToFd(out_fd_w.platform_file()));
+  ASSERT_TRUE(reader.ExtractCurrentEntryToFile(out_fd_w.file()));
   // Read the output file and compute the MD5.
   std::string output;
-  ASSERT_TRUE(base::ReadFileToString(test_dir_.AppendASCII("quux.txt"),
-                                     &output));
+  ASSERT_TRUE(base::ReadFileToString(out_path, &output));
   const std::string md5 = base::MD5String(output);
   EXPECT_EQ(kQuuxExpectedMD5, md5);
   // quux.txt should be larger than kZipBufSize so that we can exercise
   // the loop in ExtractCurrentEntry().
   EXPECT_LT(static_cast<size_t>(internal::kZipBufSize), output.size());
 }
-#endif
 
 TEST_F(ZipReaderTest, ExtractCurrentEntryToFilePath_Directory) {
   ZipReader reader;
@@ -582,4 +591,97 @@ TEST_F(ZipReaderTest, DISABLED_LeakDetectionTest) {
   }
 }
 
+// Test that when WriterDelegate::PrepareMock returns false, no other methods on
+// the delegate are called and the extraction fails.
+TEST_F(ZipReaderTest, ExtractCurrentEntryPrepareFailure) {
+  testing::StrictMock<MockWriterDelegate> mock_writer;
+
+  EXPECT_CALL(mock_writer, PrepareOutput())
+      .WillOnce(Return(false));
+
+  base::FilePath target_path(FILE_PATH_LITERAL("foo/bar/quux.txt"));
+  ZipReader reader;
+
+  ASSERT_TRUE(reader.Open(test_zip_file_));
+  ASSERT_TRUE(reader.LocateAndOpenEntry(target_path));
+  ASSERT_FALSE(reader.ExtractCurrentEntry(&mock_writer));
+}
+
+// Test that when WriterDelegate::WriteBytes returns false, no other methods on
+// the delegate are called and the extraction fails.
+TEST_F(ZipReaderTest, ExtractCurrentEntryWriteBytesFailure) {
+  testing::StrictMock<MockWriterDelegate> mock_writer;
+
+  EXPECT_CALL(mock_writer, PrepareOutput())
+      .WillOnce(Return(true));
+  EXPECT_CALL(mock_writer, WriteBytes(_, _))
+      .WillOnce(Return(false));
+
+  base::FilePath target_path(FILE_PATH_LITERAL("foo/bar/quux.txt"));
+  ZipReader reader;
+
+  ASSERT_TRUE(reader.Open(test_zip_file_));
+  ASSERT_TRUE(reader.LocateAndOpenEntry(target_path));
+  ASSERT_FALSE(reader.ExtractCurrentEntry(&mock_writer));
+}
+
+// Test that extraction succeeds when the writer delegate reports all is well.
+TEST_F(ZipReaderTest, ExtractCurrentEntrySuccess) {
+  testing::StrictMock<MockWriterDelegate> mock_writer;
+
+  EXPECT_CALL(mock_writer, PrepareOutput())
+      .WillOnce(Return(true));
+  EXPECT_CALL(mock_writer, WriteBytes(_, _))
+      .WillRepeatedly(Return(true));
+
+  base::FilePath target_path(FILE_PATH_LITERAL("foo/bar/quux.txt"));
+  ZipReader reader;
+
+  ASSERT_TRUE(reader.Open(test_zip_file_));
+  ASSERT_TRUE(reader.LocateAndOpenEntry(target_path));
+  ASSERT_TRUE(reader.ExtractCurrentEntry(&mock_writer));
+}
+
+class FileWriterDelegateTest : public ::testing::Test {
+ protected:
+  void SetUp() override {
+    ASSERT_TRUE(base::CreateTemporaryFile(&temp_file_path_));
+    file_.Initialize(temp_file_path_, (base::File::FLAG_CREATE_ALWAYS |
+                                       base::File::FLAG_READ |
+                                       base::File::FLAG_WRITE |
+                                       base::File::FLAG_TEMPORARY |
+                                       base::File::FLAG_DELETE_ON_CLOSE));
+    ASSERT_TRUE(file_.IsValid());
+  }
+
+  // Writes data to the file, leaving the current position at the end of the
+  // write.
+  void PopulateFile() {
+    static const char kSomeData[] = "this sure is some data.";
+    static const size_t kSomeDataLen = sizeof(kSomeData) - 1;
+    ASSERT_NE(-1LL, file_.Write(0LL, kSomeData, kSomeDataLen));
+  }
+
+  base::FilePath temp_file_path_;
+  base::File file_;
+};
+
+TEST_F(FileWriterDelegateTest, WriteToStartAndTruncate) {
+  // Write stuff and advance.
+  PopulateFile();
+
+  // This should rewind, write, then truncate.
+  static const char kSomeData[] = "short";
+  static const int kSomeDataLen = sizeof(kSomeData) - 1;
+  {
+    FileWriterDelegate writer(&file_);
+    ASSERT_TRUE(writer.PrepareOutput());
+    ASSERT_TRUE(writer.WriteBytes(kSomeData, kSomeDataLen));
+  }
+  ASSERT_EQ(kSomeDataLen, file_.GetLength());
+  char buf[kSomeDataLen] = {};
+  ASSERT_EQ(kSomeDataLen, file_.Read(0LL, buf, kSomeDataLen));
+  ASSERT_EQ(std::string(kSomeData), std::string(buf, kSomeDataLen));
+}
+
 }  // namespace zip