Deprecate SDCH-related net::SourceStream types

- Deprecated three SDCH-related net::SourceStream types
- Modify URLRequestHttpJob::SetUpSourceStream() to not include default case

Bug: 764434, 764433, 762686
Change-Id: I93320bfee930484da76a0a29fab2224f2b886523
Reviewed-on: https://chromium-review.googlesource.com/667731
Commit-Queue: Helen Li <xunjieli@chromium.org>
Reviewed-by: Randy Smith <rdsmith@chromium.org>
Cr-Commit-Position: refs/heads/master@{#502337}

net/filter/filter_source_stream.cc

@@ -19,7 +19,6 @@ namespace {
 
 const char kDeflate[] = "deflate";
 const char kGZip[] = "gzip";
-const char kSdch[] = "sdch";
 const char kXGZip[] = "x-gzip";
 const char kBrotli[] = "br";
 
@@ -84,8 +83,6 @@ FilterSourceStream::SourceType FilterSourceStream::ParseEncodingType(
   } else if (base::LowerCaseEqualsASCII(encoding, kGZip) ||
              base::LowerCaseEqualsASCII(encoding, kXGZip)) {
     return TYPE_GZIP;
-  } else if (base::LowerCaseEqualsASCII(encoding, kSdch)) {
-    return TYPE_SDCH;
   } else {
     return TYPE_UNKNOWN;
   }

net/filter/gzip_source_stream.cc

@@ -20,7 +20,6 @@ namespace {
 
 const char kDeflate[] = "DEFLATE";
 const char kGzip[] = "GZIP";
-const char kGzipFallback[] = "GZIP_FALLBACK";
 
 // For deflate streams, if more than this many bytes have been received without
 // an error and without adding a Zlib header, assume the original stream had a
@@ -40,6 +39,7 @@ GzipSourceStream::~GzipSourceStream() {
 std::unique_ptr<GzipSourceStream> GzipSourceStream::Create(
     std::unique_ptr<SourceStream> upstream,
     SourceStream::SourceType type) {
+  DCHECK(type == TYPE_GZIP || type == TYPE_DEFLATE);
   std::unique_ptr<GzipSourceStream> source(
       new GzipSourceStream(std::move(upstream), type));
 
@@ -62,7 +62,7 @@ bool GzipSourceStream::Init() {
   memset(zlib_stream_.get(), 0, sizeof(z_stream));
 
   int ret;
-  if (type() == TYPE_GZIP || type() == TYPE_GZIP_FALLBACK) {
+  if (type() == TYPE_GZIP) {
     ret = inflateInit2(zlib_stream_.get(), -MAX_WBITS);
   } else {
     ret = inflateInit(zlib_stream_.get());
@@ -75,8 +75,6 @@ std::string GzipSourceStream::GetTypeAsString() const {
   switch (type()) {
     case TYPE_GZIP:
       return kGzip;
-    case TYPE_GZIP_FALLBACK:
-      return kGzipFallback;
     case TYPE_DEFLATE:
       return kDeflate;
     default:
@@ -104,14 +102,8 @@ int GzipSourceStream::FilterData(IOBuffer* output_buffer,
           input_state_ = STATE_SNIFFING_DEFLATE_HEADER;
           break;
         }
-        // If this stream is not really gzipped as detected by
-        // ShouldFallbackToPlain, pretend that the zlib stream has ended.
         DCHECK_LT(0, input_data_size);
-        if (ShouldFallbackToPlain(input_data[0])) {
-          input_state_ = STATE_UNCOMPRESSED_BODY;
-        } else {
-          input_state_ = STATE_GZIP_HEADER;
-        }
+        input_state_ = STATE_GZIP_HEADER;
         break;
       }
       case STATE_GZIP_HEADER: {
@@ -276,14 +268,4 @@ bool GzipSourceStream::InsertZlibHeader() {
   return ret == Z_OK;
 }
 
-// Dumb heuristic. Gzip files always start with a two-byte magic value per RFC
-// 1952 2.3.1, so if the first byte isn't the first byte of the gzip magic, and
-// this filter is checking whether it should fallback, then fallback.
-bool GzipSourceStream::ShouldFallbackToPlain(char first_byte) {
-  if (type() != TYPE_GZIP_FALLBACK)
-    return false;
-  static const char kGzipFirstByte = 0x1f;
-  return first_byte != kGzipFirstByte;
-}
-
 }  // namespace net

net/filter/gzip_source_stream.h

@@ -82,11 +82,6 @@ class NET_EXPORT_PRIVATE GzipSourceStream : public FilterSourceStream {
   // success.
   bool InsertZlibHeader();
 
-  // Returns whether this stream looks like it could be plain text (ie, not
-  // actually gzipped). Right now this uses an extremely simple heuristic; see
-  // the source for details. This method checks the first byte of the stream.
-  bool ShouldFallbackToPlain(char first_byte);
-
   // The control block of zlib which actually does the decoding.
   // This data structure is initialized by Init and updated only by
   // FilterData(), with InsertZlibHeader() being the exception as a workaround.

net/filter/gzip_source_stream_fuzzer.cc

@@ -21,8 +21,7 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
       new net::FuzzedSourceStream(&data_provider));
 
   const net::SourceStream::SourceType kGzipTypes[] = {
-      net::SourceStream::TYPE_GZIP, net::SourceStream::TYPE_DEFLATE,
-      net::SourceStream::TYPE_GZIP_FALLBACK};
+      net::SourceStream::TYPE_GZIP, net::SourceStream::TYPE_DEFLATE};
   net::SourceStream::SourceType type =
       data_provider.PickValueInArray(kGzipTypes);
   std::unique_ptr<net::GzipSourceStream> gzip_stream =

net/filter/gzip_source_stream_unittest.cc

@@ -60,11 +60,10 @@ class GzipSourceStreamTest : public ::testing::TestWithParam<GzipTestParam> {
   GzipSourceStreamTest() : output_buffer_size_(GetParam().buffer_size) {}
 
   // Helpful function to initialize the test fixture.|type| specifies which type
-  // of GzipSourceStream to create. It must be one of TYPE_GZIP,
-  // TYPE_GZIP_FALLBACK and TYPE_DEFLATE.
+  // of GzipSourceStream to create. It must be one of TYPE_GZIP and
+  // TYPE_DEFLATE.
   void Init(SourceStream::SourceType type) {
     EXPECT_TRUE(SourceStream::TYPE_GZIP == type ||
-                SourceStream::TYPE_GZIP_FALLBACK == type ||
                 SourceStream::TYPE_DEFLATE == type);
     source_data_len_ = kBigBufferSize - kEOFMargin;
 
@@ -272,19 +271,6 @@ TEST_P(GzipSourceStreamTest, CorruptGzipHeader) {
   EXPECT_EQ("GZIP", stream()->Description());
 }
 
-TEST_P(GzipSourceStreamTest, GzipFallback) {
-  Init(SourceStream::TYPE_GZIP_FALLBACK);
-  source()->AddReadResult(source_data(), source_data_len(), OK,
-                          GetParam().mode);
-  source()->AddReadResult(nullptr, 0, OK, GetParam().mode);
-
-  std::string actual_output;
-  int rv = ReadStream(&actual_output);
-  EXPECT_EQ(static_cast<int>(source_data_len()), rv);
-  EXPECT_EQ(std::string(source_data(), source_data_len()), actual_output);
-  EXPECT_EQ("GZIP_FALLBACK", stream()->Description());
-}
-
 // This test checks that the gzip stream source works correctly on 'golden' data
 // as produced by gzip(1).
 TEST_P(GzipSourceStreamTest, GzipCorrectness) {

net/filter/source_stream_type_list.h

@@ -7,9 +7,9 @@
 SOURCE_STREAM_TYPE(BROTLI)
 SOURCE_STREAM_TYPE(DEFLATE)
 SOURCE_STREAM_TYPE(GZIP)
-SOURCE_STREAM_TYPE(GZIP_FALLBACK)
-SOURCE_STREAM_TYPE(SDCH)
-SOURCE_STREAM_TYPE(SDCH_POSSIBLE)
+SOURCE_STREAM_TYPE(GZIP_FALLBACK_DEPRECATED)
+SOURCE_STREAM_TYPE(SDCH_DEPRECATED)
+SOURCE_STREAM_TYPE(SDCH_POSSIBLE_DEPRECATED)
 SOURCE_STREAM_TYPE(INVALID)
 SOURCE_STREAM_TYPE(NONE)
 SOURCE_STREAM_TYPE(REJECTED)

net/url_request/url_request_http_job.cc

@@ -1013,15 +1013,21 @@ std::unique_ptr<SourceStream> URLRequestHttpJob::SetUpSourceStream() {
       case SourceStream::TYPE_NONE:
         // Identity encoding type. Pass through raw response body.
         return upstream;
-      case SourceStream::TYPE_SDCH:
-      // Pass through raw sdch response.
-      default:
+      case SourceStream::TYPE_UNKNOWN:
         // Unknown encoding type. Pass through raw response body.
         // Despite of reporting to UMA, request will not be canceled; though
         // it is expected that user will see malformed / garbage response.
         FilterSourceStream::ReportContentDecodingFailed(
             FilterSourceStream::TYPE_UNKNOWN);
         return upstream;
+      case SourceStream::TYPE_GZIP_FALLBACK_DEPRECATED:
+      case SourceStream::TYPE_SDCH_DEPRECATED:
+      case SourceStream::TYPE_SDCH_POSSIBLE_DEPRECATED:
+      case SourceStream::TYPE_REJECTED:
+      case SourceStream::TYPE_INVALID:
+      case SourceStream::TYPE_MAX:
+        NOTREACHED();
+        return nullptr;
     }
   }
 
@@ -1036,11 +1042,11 @@ std::unique_ptr<SourceStream> URLRequestHttpJob::SetUpSourceStream() {
         break;
       case SourceStream::TYPE_GZIP:
       case SourceStream::TYPE_DEFLATE:
-      case SourceStream::TYPE_GZIP_FALLBACK:
         downstream = GzipSourceStream::Create(std::move(upstream), type);
         break;
-      case SourceStream::TYPE_SDCH:
-      case SourceStream::TYPE_SDCH_POSSIBLE:
+      case SourceStream::TYPE_GZIP_FALLBACK_DEPRECATED:
+      case SourceStream::TYPE_SDCH_DEPRECATED:
+      case SourceStream::TYPE_SDCH_POSSIBLE_DEPRECATED:
       case SourceStream::TYPE_NONE:
       case SourceStream::TYPE_INVALID:
       case SourceStream::TYPE_REJECTED:

net/url_request/url_request_http_job_unittest.cc

@@ -178,29 +178,6 @@ TEST_F(URLRequestHttpJobSetUpSourceTest, UnknownEncoding) {
   EXPECT_EQ("Test Content", delegate_.data_received());
 }
 
-// Received a SDCH encoded response when Sdch is not advertised.
-TEST_F(URLRequestHttpJobSetUpSourceTest, SdchNotAdvertisedGotSdchResponse) {
-  MockWrite writes[] = {MockWrite(kSimpleGetMockWrite)};
-  MockRead reads[] = {MockRead("HTTP/1.1 200 OK\r\n"
-                               "Content-Encoding: sdch\r\n"
-                               "Content-Length: 12\r\n\r\n"),
-                      MockRead("Test Content")};
-
-  StaticSocketDataProvider socket_data(reads, arraysize(reads), writes,
-                                       arraysize(writes));
-  socket_factory_.AddSocketDataProvider(&socket_data);
-
-  std::unique_ptr<URLRequest> request =
-      context_.CreateRequest(GURL("http://www.example.com"), DEFAULT_PRIORITY,
-                             &delegate_, TRAFFIC_ANNOTATION_FOR_TESTS);
-  auto job = std::make_unique<TestURLRequestHttpJob>(request.get());
-  test_job_interceptor_->set_main_intercept_job(std::move(job));
-  request->Start();
-
-  base::RunLoop().Run();
-  EXPECT_EQ(ERR_CONTENT_DECODING_FAILED, delegate_.request_status());
-}
-
 class URLRequestHttpJobTest : public ::testing::Test {
  protected:
   URLRequestHttpJobTest() : context_(true) {