path: root/net/base/sdch_filter_unitest.cc

// Copyright (c) 2006-2008 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 <algorithm>
#include <string>
#include <vector>

#include "base/logging.h"
#include "base/scoped_ptr.h"
#include "net/base/filter.h"
#include "net/base/sdch_filter.h"
#include "net/url_request/url_request_http_job.cc"
#include "testing/gtest/include/gtest/gtest.h"
#include "third_party/zlib/zlib.h"

// Provide sample data and compression results with a sample VCDIFF dictionary.
// Note an SDCH dictionary has extra meta-data before the VCDIFF text.
const char kTtestVcdiffDictionary[] = "DictionaryFor"
    "SdchCompression1SdchCompression2SdchCompression3SdchCompression\n";
// Pre-compression test data.
const char kTestData[] = "TestData "
    "SdchCompression1SdchCompression2SdchCompression3SdchCompression\n";
// Note SDCH compressed data will include a reference to the SDCH dictionary.
const char kCompressedTestData[] =
    "\326\303\304\0\0\001M\0\022I\0\t\003\001TestData \n\023\100\r";

namespace {

class SdchFilterTest : public testing::Test {
 protected:
  SdchFilterTest()
    : test_vcdiff_dictionary_(kTtestVcdiffDictionary,
                              sizeof(kTtestVcdiffDictionary) - 1),
      expanded_(kTestData, sizeof(kTestData) - 1),
      compressed_test_data_(kCompressedTestData,
                            sizeof(kCompressedTestData) - 1),
      sdch_manager_(new SdchManager) {
  }

  const std::string test_vcdiff_dictionary_;
  const std::string compressed_test_data_;
  const std::string expanded_;  // Desired final, decompressed data.

  scoped_ptr<SdchManager> sdch_manager_;  // A singleton database.
};


TEST_F(SdchFilterTest, Hashing) {
  std::string client_hash, server_hash;
  std::string dictionary("test contents");
  SdchManager::GenerateHash(dictionary, &client_hash, &server_hash);

  EXPECT_EQ(client_hash, "lMQBjS3P");
  EXPECT_EQ(server_hash, "MyciMVll");
}


//------------------------------------------------------------------------------
// Provide a generic helper function for trying to filter data.
// This function repeatedly calls the filter to process data, until the entire
// source is consumed.  The return value from the filter is appended to output.
// This allows us to vary input and output block sizes in order to test for edge
// effects (boundary effects?) during the filtering process.
// This function provides data to the filter in blocks of no-more-than the
// specified input_block_length.  It allows the filter to fill no more than
// output_buffer_length in any one call to proccess (a.k.a., Read) data, and
// concatenates all these little output blocks into the singular output string.
static bool FilterTestData(const std::string& source,
                           size_t input_block_length,
                           const size_t output_buffer_length,
                           Filter* filter, std::string* output) {
  CHECK(input_block_length > 0);
  Filter::FilterStatus status(Filter::FILTER_NEED_MORE_DATA);
  size_t source_index = 0;
  scoped_array<char> output_buffer(new char[output_buffer_length]);
  size_t input_amount = std::min(input_block_length,
      static_cast<size_t>(filter->stream_buffer_size()));

  do {
    int copy_amount = std::min(input_amount, source.size() - source_index);
    if (copy_amount > 0 && status == Filter::FILTER_NEED_MORE_DATA) {
      memcpy(filter->stream_buffer(), source.data() + source_index,
             copy_amount);
      filter->FlushStreamBuffer(copy_amount);
      source_index += copy_amount;
    }
    int buffer_length = output_buffer_length;
    status = filter->ReadData(output_buffer.get(), &buffer_length);
    output->append(output_buffer.get(), buffer_length);
    if (status == Filter::FILTER_ERROR)
      return false;
    if (copy_amount == 0 && buffer_length == 0)
      return true;
  } while (1);
}
//------------------------------------------------------------------------------


TEST_F(SdchFilterTest, BasicBadDicitonary) {
  SdchManager::enable_sdch_support("");

  std::vector<std::string> filters;
  filters.push_back("sdch");
  int kInputBufferSize(30);
  char output_buffer[20];
  size_t kOutputBufferSize(20);
  scoped_ptr<Filter> filter(Filter::Factory(filters, "missing-mime",
                                            kInputBufferSize));
  filter->SetURL(GURL("http://ignore.com"));


  // With no input data, try to read output.
  int output_bytes_or_buffer_size = sizeof(output_buffer);
  Filter::FilterStatus status = filter->ReadData(output_buffer,
                                                 &output_bytes_or_buffer_size);

  EXPECT_EQ(0, output_bytes_or_buffer_size);
  EXPECT_EQ(Filter::FILTER_NEED_MORE_DATA, status);

  // Supply bogus data (which doesnt't yet specify a full dictionary hash).
  // Dictionary hash is 8 characters followed by a null.
  std::string dictionary_hash_prefix("123");

  char* input_buffer = filter->stream_buffer();
  int input_buffer_size = filter->stream_buffer_size();
  EXPECT_EQ(kInputBufferSize, input_buffer_size);

  EXPECT_LT(static_cast<int>(dictionary_hash_prefix.size()),
            input_buffer_size);
  memcpy(input_buffer, dictionary_hash_prefix.data(),
         dictionary_hash_prefix.size());
  filter->FlushStreamBuffer(dictionary_hash_prefix.size());

  // With less than a dictionary specifier, try to read output.
  output_bytes_or_buffer_size = sizeof(output_buffer);
  status = filter->ReadData(output_buffer, &output_bytes_or_buffer_size);

  EXPECT_EQ(0, output_bytes_or_buffer_size);
  EXPECT_EQ(Filter::FILTER_NEED_MORE_DATA, status);

  // Provide enough data to complete *a* hash, but it is bogus, and not in our
  // list of dictionaries, so the filter should error out immediately.
  std::string dictionary_hash_postfix("4abcd\0", 6);

  CHECK(dictionary_hash_postfix.size() <
        static_cast<size_t>(input_buffer_size));
  memcpy(input_buffer, dictionary_hash_postfix.data(),
         dictionary_hash_postfix.size());
  filter->FlushStreamBuffer(dictionary_hash_postfix.size());

  // With a non-existant dictionary specifier, try to read output.
  output_bytes_or_buffer_size = sizeof(output_buffer);
  status = filter->ReadData(output_buffer, &output_bytes_or_buffer_size);

  EXPECT_EQ(0, output_bytes_or_buffer_size);
  EXPECT_EQ(Filter::FILTER_ERROR, status);
}


TEST_F(SdchFilterTest, BasicDictionary) {
  SdchManager::enable_sdch_support("");

  const std::string kSampleDomain = "sdchtest.com";

  // Construct a valid SDCH dictionary from a VCDIFF dictionary.
  std::string dictionary("Domain: ");
  dictionary.append(kSampleDomain);
  dictionary.append("\n\n");
  dictionary.append(test_vcdiff_dictionary_);
  std::string client_hash;
  std::string server_hash;
  SdchManager::GenerateHash(dictionary, &client_hash, &server_hash);
  std::string url_string = "http://" + kSampleDomain;

  GURL url(url_string);
  bool status = sdch_manager_->AddSdchDictionary(dictionary, url);
  EXPECT_TRUE(status);

  // Check we can't add it twice.
  status = sdch_manager_->AddSdchDictionary(dictionary, url);
  EXPECT_FALSE(status);  // Already loaded.

  // Build compressed data that refers to our dictionary.
  std::string compressed(server_hash);
  compressed.append("\0", 1);
  compressed.append(compressed_test_data_);

  std::vector<std::string> filters;
  filters.push_back("sdch");

  // First try with a large buffer (larger than test input, or compressed data).
  int kInputBufferSize(100);
  scoped_ptr<Filter> filter(Filter::Factory(filters, "missing-mime",
                                            kInputBufferSize));
  filter->SetURL(url);

  size_t feed_block_size = 100;
  size_t output_block_size = 100;
  std::string output;
  status = FilterTestData(compressed, feed_block_size, output_block_size,
                          filter.get(), &output);
  EXPECT_TRUE(status);
  EXPECT_TRUE(output == expanded_);

  // Now try with really small buffers (size 1) to check for edge effects.
  filter.reset((Filter::Factory(filters, "missing-mime", kInputBufferSize)));
  filter->SetURL(url);

  feed_block_size = 1;
  output_block_size = 1;
  output.clear();
  status = FilterTestData(compressed, feed_block_size, output_block_size,
                          filter.get(), &output);
  EXPECT_TRUE(status);
  EXPECT_TRUE(output == expanded_);

  // Now try with content arriving from the "wrong" domain.
  // This tests CanSet() in the sdch_manager_->
  filter.reset((Filter::Factory(filters, "missing-mime", kInputBufferSize)));
  filter->SetURL(GURL("http://www.wrongdomain.com"));

  feed_block_size = 100;
  output_block_size = 100;
  output.clear();
  status = FilterTestData(compressed, feed_block_size, output_block_size,
                          filter.get(), &output);
  EXPECT_FALSE(status);  // Couldn't decode.
  EXPECT_TRUE(output == "");  // No output written.


  // Now check that path restrictions on dictionary are being enforced.

  // Create a dictionary with a path restriction, by prefixing old dictionary.
  const std::string path("/special_path/bin");
  std::string dictionary_with_path("Path: " + path + "\n");
  dictionary_with_path.append(dictionary);
  std::string pathed_client_hash;
  std::string pathed_server_hash;
  SdchManager::GenerateHash(dictionary_with_path,
                            &pathed_client_hash, &pathed_server_hash);
  status = sdch_manager_->AddSdchDictionary(dictionary_with_path, url);
  EXPECT_TRUE(status);

  // Build compressed data that refers to our dictionary
  std::string compressed_for_path(pathed_server_hash);
  compressed_for_path.append("\0", 1);
  compressed_for_path.append(compressed_test_data_);

  // Test decode the path data, arriving from a valid path.
  filter.reset((Filter::Factory(filters, "missing-mime", kInputBufferSize)));
  filter->SetURL(GURL(url_string + path));

  feed_block_size = 100;
  output_block_size = 100;
  output.clear();
  status = FilterTestData(compressed_for_path, feed_block_size,
                          output_block_size, filter.get(), &output);
  EXPECT_TRUE(status);
  EXPECT_TRUE(output == expanded_);

  // Test decode the path data, arriving from a invalid path.
  filter.reset((Filter::Factory(filters, "missing-mime", kInputBufferSize)));
  filter->SetURL(GURL(url_string));

  feed_block_size = 100;
  output_block_size = 100;
  output.clear();
  status = FilterTestData(compressed_for_path, feed_block_size,
                          output_block_size, filter.get(), &output);
  EXPECT_FALSE(status);  // Couldn't decode.
  EXPECT_TRUE(output == "");  // No output written.


  // Create a dictionary with a port restriction, by prefixing old dictionary.
  const std::string port("502");
  std::string dictionary_with_port("Port: " + port + "\n");
  dictionary_with_port.append("Port: 80\n");  // Add default port.
  dictionary_with_port.append(dictionary);
  std::string ported_client_hash;
  std::string ported_server_hash;
  SdchManager::GenerateHash(dictionary_with_port,
                            &ported_client_hash, &ported_server_hash);
  status = sdch_manager_->AddSdchDictionary(dictionary_with_port,
                                            GURL(url_string + ":" + port));
  EXPECT_TRUE(status);

  // Build compressed data that refers to our dictionary
  std::string compressed_for_port(ported_server_hash);
  compressed_for_port.append("\0", 1);
  compressed_for_port.append(compressed_test_data_);

  // Test decode the port data, arriving from a valid port.
  filter.reset((Filter::Factory(filters, "missing-mime", kInputBufferSize)));
  filter->SetURL(GURL(url_string + ":" + port));

  feed_block_size = 100;
  output_block_size = 100;
  output.clear();
  status = FilterTestData(compressed_for_port, feed_block_size,
                          output_block_size, filter.get(), &output);
  EXPECT_TRUE(status);
  EXPECT_TRUE(output == expanded_);

  // Test decode the port data, arriving from a valid (default) port.
  filter.reset((Filter::Factory(filters, "missing-mime", kInputBufferSize)));
  filter->SetURL(GURL(url_string));  // Default port.

  feed_block_size = 100;
  output_block_size = 100;
  output.clear();
  status = FilterTestData(compressed_for_port, feed_block_size,
                          output_block_size, filter.get(), &output);
  EXPECT_TRUE(status);
  EXPECT_TRUE(output == expanded_);

  // Test decode the port data, arriving from a invalid port.
  filter.reset((Filter::Factory(filters, "missing-mime", kInputBufferSize)));
  filter->SetURL(GURL(url_string + ":" + port + "1"));

  feed_block_size = 100;
  output_block_size = 100;
  output.clear();
  status = FilterTestData(compressed_for_port, feed_block_size,
                          output_block_size, filter.get(), &output);
  EXPECT_FALSE(status);  // Couldn't decode.
  EXPECT_TRUE(output == "");  // No output written.
}


// Test that filters can be cascaded (chained) so that the output of one filter
// is processed by the next one.  This is most critical for SDCH, which is
// routinely followed by gzip (during encoding).  The filter we'll test for will
// do the gzip decoding first, and then decode the SDCH content.
TEST_F(SdchFilterTest, FilterChaining) {
  const std::string kSampleDomain = "sdchtest.com";

  // Construct a valid SDCH dictionary from a VCDIFF dictionary.
  std::string dictionary("Domain: ");
  dictionary.append(kSampleDomain);
  dictionary.append("\n\n");
  dictionary.append(test_vcdiff_dictionary_);
  std::string client_hash;
  std::string server_hash;
  SdchManager::GenerateHash(dictionary, &client_hash, &server_hash);
  std::string url_string = "http://" + kSampleDomain;

  GURL url(url_string);
  bool status = sdch_manager_->AddSdchDictionary(dictionary, url);
  EXPECT_TRUE(status);

  // Check we can't add it twice.
  status = sdch_manager_->AddSdchDictionary(dictionary, url);
  EXPECT_FALSE(status);  // Already loaded.

  // Build compressed sdch encoded data that refers to our dictionary.
  std::string sdch_compressed(server_hash);
  sdch_compressed.append("\0", 1);
  sdch_compressed.append(compressed_test_data_);

  // Use Gzip to compress the sdch sdch_compressed data.
  z_stream zlib_stream;
  memset(&zlib_stream, 0, sizeof(zlib_stream));
  int code;

  // Initialize zlib
  code = deflateInit2(&zlib_stream, Z_DEFAULT_COMPRESSION, Z_DEFLATED,
                      -MAX_WBITS,
                      8,  // DEF_MEM_LEVEL
                      Z_DEFAULT_STRATEGY);

  CHECK(code == Z_OK);

  // Fill in zlib control block
  zlib_stream.next_in = bit_cast<Bytef*>(sdch_compressed.data());
  zlib_stream.avail_in = sdch_compressed.size();

  // Assume we can compress into similar buffer (add 100 bytes to be sure).
  size_t gzip_compressed_length = zlib_stream.avail_in + 100;
  scoped_array<char> gzip_compressed(new char[gzip_compressed_length]);
  zlib_stream.next_out = bit_cast<Bytef*>(gzip_compressed.get());
  zlib_stream.avail_out = gzip_compressed_length;

  // The GZIP header (see RFC 1952):
  //   +---+---+---+---+---+---+---+---+---+---+
  //   |ID1|ID2|CM |FLG|     MTIME     |XFL|OS |
  //   +---+---+---+---+---+---+---+---+---+---+
  //     ID1     \037
  //     ID2     \213
  //     CM      \010 (compression method == DEFLATE)
  //     FLG     \000 (special flags that we do not support)
  //     MTIME   Unix format modification time (0 means not available)
  //     XFL     2-4? DEFLATE flags
  //     OS      ???? Operating system indicator (255 means unknown)
  //
  // Header value we generate:
  const char kGZipHeader[] = { '\037', '\213', '\010', '\000', '\000',
                               '\000', '\000', '\000', '\002', '\377' };
  CHECK(zlib_stream.avail_out > sizeof(kGZipHeader));
  memcpy(zlib_stream.next_out, kGZipHeader, sizeof(kGZipHeader));
  zlib_stream.next_out += sizeof(kGZipHeader);
  zlib_stream.avail_out -= sizeof(kGZipHeader);

  // Do deflate
  code = MOZ_Z_deflate(&zlib_stream, Z_FINISH);
  gzip_compressed_length -= zlib_stream.avail_out;
  std::string compressed(gzip_compressed.get(), gzip_compressed_length);

  // Construct a chained filter.
  std::vector<std::string> filters;
  filters.push_back("sdch");
  filters.push_back("gzip");

  // First try with a large buffer (larger than test input, or compressed data).
  int kInputBufferSize(100);
  scoped_ptr<Filter> filter(Filter::Factory(filters, "missing-mime",
                                            kInputBufferSize));
  filter->SetURL(url);

  size_t feed_block_size = 100;
  size_t output_block_size = 100;
  std::string output;
  status = FilterTestData(compressed, feed_block_size, output_block_size,
                          filter.get(), &output);
  EXPECT_TRUE(status);
  EXPECT_TRUE(output == expanded_);

  // Next try with a tiny buffer to cover edge effects.
  filter.reset(Filter::Factory(filters, "missing-mime", kInputBufferSize));
  filter->SetURL(url);

  feed_block_size = 1;
  output_block_size = 1;
  output.clear();
  status = FilterTestData(compressed, feed_block_size, output_block_size,
                          filter.get(), &output);
  EXPECT_TRUE(status);
  EXPECT_TRUE(output == expanded_);
}

};  // namespace anonymous