[ON HOLD] Implement pull-based design for content decoding

net/filter/gzip_stream_source_unittest.cc

Index: net/filter/gzip_stream_source_unittest.cc
diff --git a/net/filter/gzip_stream_source_unittest.cc b/net/filter/gzip_stream_source_unittest.cc
new file mode 100644
index 0000000000000000000000000000000000000000..2a2c7761bd6a263a8779ca2c6a551f14bdc3cf0c
--- /dev/null
+++ b/net/filter/gzip_stream_source_unittest.cc
@@ -0,0 +1,313 @@
+// Copyright 2016 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 "base/bind.h"
+#include "base/bit_cast.h"
+#include "base/callback.h"
+#include "net/base/completion_callback.h"
+#include "net/base/io_buffer.h"
+#include "net/base/test_completion_callback.h"
+#include "net/filter/gzip_stream_source.h"
+#include "net/filter/mock_stream_source.h"
+#include "testing/gtest/include/gtest/gtest.h"
+#include "third_party/zlib/zlib.h"
+
+namespace net {
+
+namespace {
+
+const size_t kBufferSize = 4096;
+
+// How many bytes to leave unused at the end of |source_data_|. This margin is
+// present so that tests that need to append data after the zlib EOF do not run
+// out of room in the output buffer.
+const size_t kEOFMargin = 64;
+
+}  // namespace
+
+class GzipStreamSourceTest : public ::testing::Test {
+ protected:
+  void Init() { Init(false); }
+
+  // If |allow_gzip_fallback| is true, will use
+  // GZIP_STREAM_SOURCE_GZIP_WITH_FALLBACK when constructing |gzip_stream_|.
+  void Init(bool allow_gzip_fallback) {
+    source_data_len_ = kBufferSize - kEOFMargin;
+
+    for (size_t i = 0; i < source_data_len_; i++)
+      source_data_[i] = i % 256;
+
+    deflated_data_len_ = kBufferSize;
+
+    Compress(source_data_, source_data_len_, deflated_data_,
+             &deflated_data_len_, false);
+
+    gzipped_data_ = new char[kBufferSize];
+    gzipped_data_len_ = kBufferSize;
+
+    Compress(source_data_, source_data_len_, gzipped_data_, &gzipped_data_len_,
+             true);
+
+    output_buffer_ = new IOBuffer(kBufferSize);
+
+    std::unique_ptr<MockStreamSource> deflate_source(new MockStreamSource);
+    deflate_source_ = deflate_source.get();
+    deflate_stream_ =
+        GzipStreamSource::Create(std::move(deflate_source),
+                                 GzipStreamSource::GZIP_STREAM_SOURCE_DEFLATE);
+
+    std::unique_ptr<MockStreamSource> source(new MockStreamSource);
+    source_ = source.get();
+    if (allow_gzip_fallback) {
+      gzip_stream_ = GzipStreamSource::Create(
+          std::move(source),
+          GzipStreamSource::GZIP_STREAM_SOURCE_GZIP_WITH_FALLBACK);
+    } else {
+      gzip_stream_ = GzipStreamSource::Create(
+          std::move(source), GzipStreamSource::GZIP_STREAM_SOURCE_GZIP);
+    }
+  }
+
+  void Compress(char* source,
+                size_t source_len,
+                char* dest,
+                size_t* dest_len,
+                bool gzip_framing) {
+    size_t dest_left = *dest_len;
+    z_stream zlib_stream;
+    memset(&zlib_stream, 0, sizeof(zlib_stream));
+    int code;
+    if (gzip_framing) {
+      const int kMemLevel = 8;  // the default, see deflateInit2(3)
+      code = deflateInit2(&zlib_stream, Z_DEFAULT_COMPRESSION, Z_DEFLATED,
+                          -MAX_WBITS, kMemLevel, Z_DEFAULT_STRATEGY);
+    } else {
+      code = deflateInit(&zlib_stream, Z_DEFAULT_COMPRESSION);
+    }
+    DCHECK_EQ(Z_OK, code);
+
+    // If compressing with gzip framing, prepend a gzip header. See RFC 1952 2.2
+    // and 2.3 for more information.
+    if (gzip_framing) {
+      const unsigned char gzip_header[] = {
+          0x1f,
+          0x8b,  // magic number
+          0x08,  // CM 0x08 == "deflate"
+          0x00,  // FLG 0x00 == nothing
+          0x00, 0x00, 0x00,
+          0x00,  // MTIME 0x00000000 == no mtime
+          0x00,  // XFL 0x00 == nothing
+          0xff,  // OS 0xff == unknown
+      };
+      DCHECK_GE(dest_left, sizeof(gzip_header));
+      memcpy(dest, gzip_header, sizeof(gzip_header));
+      dest += sizeof(gzip_header);
+      dest_left -= sizeof(gzip_header);
+    }
+
+    zlib_stream.next_in = bit_cast<Bytef*>(source);
+    zlib_stream.avail_in = source_len;
+    zlib_stream.next_out = bit_cast<Bytef*>(dest);
+    zlib_stream.avail_out = dest_left;
+
+    code = deflate(&zlib_stream, Z_FINISH);
+    DCHECK_EQ(Z_STREAM_END, code);
+    dest_left = zlib_stream.avail_out;
+
+    deflateEnd(&zlib_stream);
+    *dest_len -= dest_left;
+  }
+
+  char* source_data() { return source_data_; }
+  size_t source_data_len() { return source_data_len_; }
+
+  char* deflated_data() { return deflated_data_; }
+  size_t deflated_data_len() { return deflated_data_len_; }
+
+  char* gzipped_data() { return gzipped_data_; }
+  size_t gzipped_data_len() { return gzipped_data_len_; }
+
+  IOBuffer* output_buffer() { return output_buffer_.get(); }
+  char* output_data() { return output_buffer_->data(); }
+  size_t output_buffer_size() { return kBufferSize; }
+
+  MockStreamSource* deflate_source() { return deflate_source_; }
+  MockStreamSource* source() { return source_; }
+  GzipStreamSource* gzip_stream() { return gzip_stream_.get(); }
+
+  void AddTrailingDeflatedData(const char* data, size_t data_len) {
+    DCHECK_LE(data_len, kBufferSize - deflated_data_len_);
+    memcpy(deflated_data_ + deflated_data_len_, data, data_len);
+    deflated_data_len_ += data_len;
+  }
+
+  int ReadStream(GzipStreamSource* stream, const CompletionCallback& callback) {
+    return stream->Read(output_buffer(), output_buffer_size(), callback);
+  }
+
+  int ReadDeflateStream(const CompletionCallback& callback) {
+    return ReadStream(deflate_stream_.get(), callback);
+  }
+
+  int ReadGzipStream(const CompletionCallback& callback) {
+    return ReadStream(gzip_stream_.get(), callback);
+  }
+
+ private:
+  char source_data_[kBufferSize];
+  size_t source_data_len_;
+
+  char deflated_data_[kBufferSize];
+  size_t deflated_data_len_;
+
+  char* gzipped_data_;
+  size_t gzipped_data_len_;
+
+  scoped_refptr<IOBuffer> output_buffer_;
+
+  MockStreamSource* deflate_source_;
+  std::unique_ptr<GzipStreamSource> deflate_stream_;
+  MockStreamSource* source_;
+  std::unique_ptr<GzipStreamSource> gzip_stream_;
+};
+
+TEST_F(GzipStreamSourceTest, EmptyStream) {
+  Init();
+  deflate_source()->AddReadResult("", 0, OK, true);
+  TestCompletionCallback callback;
+  int result = ReadDeflateStream(callback.callback());
+  EXPECT_EQ(OK, result);
+  EXPECT_EQ("GZIP", gzip_stream()->OrderedTypeStringList());
+}
+
+TEST_F(GzipStreamSourceTest, DeflateOneBlockSync) {
+  Init();
+  deflate_source()->AddReadResult(deflated_data(), deflated_data_len(), OK,
+                                  true);
+  TestCompletionCallback callback;
+  int result = ReadDeflateStream(callback.callback());
+  EXPECT_EQ(static_cast<int>(source_data_len()), result);
+  EXPECT_EQ(0, memcmp(output_data(), source_data(), source_data_len()));
+  EXPECT_EQ("GZIP", gzip_stream()->OrderedTypeStringList());
+}
+
+TEST_F(GzipStreamSourceTest, GzipOneBlockSync) {
+  Init();
+  source()->AddReadResult(gzipped_data(), gzipped_data_len(), OK, true);
+  TestCompletionCallback callback;
+  int result = ReadGzipStream(callback.callback());
+  EXPECT_EQ(static_cast<int>(source_data_len()), result);
+  EXPECT_EQ(0, memcmp(output_data(), source_data(), source_data_len()));
+  EXPECT_EQ("GZIP", gzip_stream()->OrderedTypeStringList());
+}
+
+TEST_F(GzipStreamSourceTest, DeflateTwoBlocksSync) {
+  Init();
+  deflate_source()->AddReadResult(deflated_data(), 10, OK, true);
+  deflate_source()->AddReadResult(deflated_data() + 10,
+                                  deflated_data_len() - 10, OK, true);
+  TestCompletionCallback callback;
+  char buffer[kBufferSize];
+  int first_bytes_read = ReadDeflateStream(callback.callback());
+  EXPECT_LE(OK, first_bytes_read);
+  memcpy(buffer, output_data(), first_bytes_read);
+  int second_bytes_read = ReadDeflateStream(callback.callback());
+  EXPECT_LE(OK, second_bytes_read);
+  EXPECT_EQ(static_cast<int>(source_data_len()),
+            first_bytes_read + second_bytes_read);
+  memcpy(buffer + first_bytes_read, output_data(), second_bytes_read);
+  memcpy(output_data(), buffer, first_bytes_read + second_bytes_read);
+  EXPECT_EQ(0, memcmp(output_data(), source_data(), source_data_len()));
+  EXPECT_EQ("GZIP", gzip_stream()->OrderedTypeStringList());
+}
+
+TEST_F(GzipStreamSourceTest, DeflateOneBlockAsync) {
+  Init();
+  deflate_source()->AddReadResult(deflated_data(), deflated_data_len(), OK,
+                                  false);
+  TestCompletionCallback callback;
+  EXPECT_EQ(ERR_IO_PENDING, ReadDeflateStream(callback.callback()));
+  deflate_source()->CompleteNextRead();
+  EXPECT_EQ(static_cast<int>(source_data_len()), callback.WaitForResult());
+  EXPECT_EQ(0, memcmp(output_data(), source_data(), source_data_len()));
+  EXPECT_EQ("GZIP", gzip_stream()->OrderedTypeStringList());
+}
+
+TEST_F(GzipStreamSourceTest, PassThroughAfterEOF) {
+  Init();
+  char test_data[] = "Hello, World!";
+  AddTrailingDeflatedData(test_data, sizeof(test_data));
+  deflate_source()->AddReadResult(deflated_data(), deflated_data_len(), OK,
+                                  true);
+  // Compressed and uncompressed data get returned as separate Read() results,
+  // so this test has to call Read twice.
+  TestCompletionCallback callback;
+  int bytes_read = ReadDeflateStream(callback.callback());
+  EXPECT_EQ(static_cast<int>(source_data_len() + sizeof(test_data)),
+            bytes_read);
+  EXPECT_EQ(0, memcmp(output_data(), source_data(), source_data_len()));
+  EXPECT_EQ(0, memcmp(output_data() + source_data_len(), test_data,
+                      sizeof(test_data)));
+  EXPECT_EQ("GZIP", gzip_stream()->OrderedTypeStringList());
+}
+
+TEST_F(GzipStreamSourceTest, MissingZlibHeader) {
+  Init();
+  const size_t kZlibHeaderLen = 2;
+  deflate_source()->AddReadResult(deflated_data() + kZlibHeaderLen,
+                                  deflated_data_len() - kZlibHeaderLen, OK,
+                                  true);
+  TestCompletionCallback callback;
+  int bytes_read = ReadDeflateStream(callback.callback());
+  EXPECT_EQ(static_cast<int>(source_data_len()), bytes_read);
+  EXPECT_EQ(0, memcmp(output_data(), source_data(), source_data_len()));
+  EXPECT_EQ("GZIP", gzip_stream()->OrderedTypeStringList());
+}
+
+// A slight wrinkle: since the test GZip stream runs with gzip_fallback set to
+// true, corrupting the first byte instead of the second byte will cause the
+// gzip stream to falsely accept the corrupt data and pass it through untouched.
+TEST_F(GzipStreamSourceTest, CorruptGzipHeader) {
+  Init();
+  gzipped_data()[1] = 0;
+  source()->AddReadResult(gzipped_data(), gzipped_data_len(), OK, true);
+  TestCompletionCallback callback;
+  int bytes_read = ReadGzipStream(callback.callback());
+  EXPECT_EQ(ERR_CONTENT_DECODING_FAILED, bytes_read);
+  EXPECT_EQ("GZIP", gzip_stream()->OrderedTypeStringList());
+}
+
+TEST_F(GzipStreamSourceTest, GzipFallback) {
+  Init(/*allow_gzip_fallback=*/true);
+  source()->AddReadResult(source_data(), source_data_len(), OK, true);
+  TestCompletionCallback callback;
+  int bytes_read = ReadGzipStream(callback.callback());
+  EXPECT_EQ(static_cast<int>(source_data_len()), bytes_read);
+  EXPECT_EQ(0, memcmp(output_data(), source_data(), source_data_len()));
+  EXPECT_EQ("GZIP", gzip_stream()->OrderedTypeStringList());
+}
+
+// This test checks that the gzip stream source works correctly on 'golden' data
+// as produced by gzip(1).
+TEST_F(GzipStreamSourceTest, GzipCorrectness) {
+  Init();
+  char plain_data[] = "Hello, World!";
+  unsigned char gzip_data[] = {
+      // From:
+      //   echo -n 'Hello, World!' | gzip | xxd -i | sed -e 's/^/  /'
+      0x1f, 0x8b, 0x08, 0x00, 0x2b, 0x02, 0x84, 0x55, 0x00, 0x03, 0xf3,
+      0x48, 0xcd, 0xc9, 0xc9, 0xd7, 0x51, 0x08, 0xcf, 0x2f, 0xca, 0x49,
+      0x51, 0x04, 0x00, 0xd0, 0xc3, 0x4a, 0xec, 0x0d, 0x00, 0x00, 0x00};
+  source()->AddReadResult(reinterpret_cast<char*>(gzip_data), sizeof(gzip_data),
+                          OK, true);
+  TestCompletionCallback callback;
+  int bytes_read = ReadGzipStream(callback.callback());
+  // Using strlen(3) here because echo doesn't leave the null terminator on the
+  // string.
+  EXPECT_EQ(static_cast<int>(strlen(plain_data)), bytes_read);
+  EXPECT_EQ(0, memcmp(output_data(), plain_data, strlen(plain_data)));
+  EXPECT_EQ("GZIP", gzip_stream()->OrderedTypeStringList());
+}
+
+}  // namespace