Add brotli content-encoding filter.

net/filter/brotli_filter_unittest.cc

+// Copyright 2015 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/files/file_util.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/path_service.h"
+#include "net/base/io_buffer.h"
+#include "net/filter/brotli_filter.h"
+#include "net/filter/mock_filter_context.h"
+#include "testing/gtest/include/gtest/gtest.h"
+#include "testing/platform_test.h"
+
+namespace {
+const int kDefaultBufferSize = 4096;
+const int kSmallBufferSize = 128;
+}  // namespace
+
+namespace net {
+
+// These tests use the path service, which uses autoreleased objects on the
+// Mac, so this needs to be a PlatformTest.
+class BrotliUnitTest : public PlatformTest {
+ protected:
+  void SetUp() override {
+    PlatformTest::SetUp();
+
+    // Get the path of data directory.
+    base::FilePath data_dir;
+    PathService::Get(base::DIR_SOURCE_ROOT, &data_dir);
+    data_dir = data_dir.AppendASCII("net");
+    data_dir = data_dir.AppendASCII("data");
+    data_dir = data_dir.AppendASCII("filter_unittests");
+
+    // Read data from the original file into buffer.
+    base::FilePath file_path;
+    file_path = data_dir.AppendASCII("google.txt");
+    ASSERT_TRUE(base::ReadFileToString(file_path, &source_buffer_));
+
+    // Read data from the encoded file into buffer.
+    base::FilePath encoded_file_path;
+    encoded_file_path = data_dir.AppendASCII("google.br");
+    ASSERT_TRUE(base::ReadFileToString(encoded_file_path, &encoded_buffer_));
+    ASSERT_GE(kDefaultBufferSize, static_cast<int>(encoded_buffer_.size()));
+  }
+
+  void TearDown() override { PlatformTest::TearDown(); }

[Randy Smith (Not in Mondays), 2015/12/07 22:27:28]

nit, suggestion: I don't personally feel like putting in an override just to
call the base class makes sense, but I could see this as a style thing (i.e. if
there's a SetUp(), there should be a TearDown()), so up to you.

[eustas, 2015/12/08 11:31:31]

Ooops, didn't notice this (copied from zip filter unittest).
You are right, doesn't make much sense to proxy the base class method.

+
+  // Use filter to decode compressed data, and compare the decoded result with
+  // the orginal data.
+  // Parameters: |source| and |source_len| are original data and its size.
+  // |encoded_source| and |encoded_source_len| are compressed data and its size.
+  // |output_buffer_size| specifies the size of buffer to read out data from
+  // filter.
+  void DecodeAndCompareWithFilter(Filter* filter,
+                                  const char* source,
+                                  int source_len,
+                                  const char* encoded_source,
+                                  int encoded_source_len,
+                                  int output_buffer_size) {
+    // Make sure we have enough space to hold the decoding output.
+    ASSERT_GE(kDefaultBufferSize, source_len);
+    ASSERT_GE(kDefaultBufferSize, output_buffer_size);
+
+    char decode_buffer[kDefaultBufferSize];
+    char* decode_next = decode_buffer;
+    int decode_avail_size = kDefaultBufferSize;
+
+    const char* encode_next = encoded_source;
+    int encode_avail_size = encoded_source_len;
+
+    int code = Filter::FILTER_OK;
+    while (code != Filter::FILTER_DONE) {
+      int encode_data_len =
+          std::min(encode_avail_size, filter->stream_buffer_size());
+      memcpy(filter->stream_buffer()->data(), encode_next, encode_data_len);
+      filter->FlushStreamBuffer(encode_data_len);
+      encode_next += encode_data_len;
+      encode_avail_size -= encode_data_len;
+
+      while (true) {
+        int decode_data_len = std::min(decode_avail_size, output_buffer_size);
+
+        code = filter->ReadData(decode_next, &decode_data_len);
+        decode_next += decode_data_len;
+        decode_avail_size -= decode_data_len;
+
+        ASSERT_NE(Filter::FILTER_ERROR, code);
+
+        if (code == Filter::FILTER_NEED_MORE_DATA ||
+            code == Filter::FILTER_DONE) {
+          break;
+        }
+      }
+    }
+
+    // Compare the decoding result with source data
+    int decode_total_data_len = kDefaultBufferSize - decode_avail_size;
+    EXPECT_EQ(source_len, decode_total_data_len);
+    EXPECT_EQ(memcmp(source, decode_buffer, source_len), 0);
+  }
+
+  // Unsafe function to use filter to decode compressed data.
+  // Parameters: |source| and |source_len| are compressed data and its size.
+  // |dest| is the buffer for decoding results. Upon entry, |*dest_len| is the
+  // size of the output buffer. Upon exit, |*dest_len| is the number of chars
+  // written into the buffer.
+  int DecodeAllWithFilter(Filter* filter,
+                          const char* source,
+                          int source_len,
+                          char* dest,
+                          int* dest_len) {
+    memcpy(filter->stream_buffer()->data(), source, source_len);
+    filter->FlushStreamBuffer(source_len);
+    return filter->ReadData(dest, dest_len);
+  }
+
+  void InitFilter() {
+    std::vector<Filter::FilterType> filter_types;
+    filter_types.push_back(Filter::FILTER_TYPE_BROTLI);
+    filter_.reset(Filter::Factory(filter_types, filter_context_));
+    ASSERT_TRUE(filter_.get());
+    ASSERT_LE(kDefaultBufferSize, filter_->stream_buffer_size());
+  }
+
+  void InitFilterWithBufferSize(int buffer_size) {
+    std::vector<Filter::FilterType> filter_types;
+    filter_types.push_back(Filter::FILTER_TYPE_BROTLI);
+    filter_.reset(
+        Filter::FactoryForTests(filter_types, filter_context_, buffer_size));
+    ASSERT_TRUE(filter_.get());
+  }
+
+  const char* source_buffer() const { return source_buffer_.data(); }
+  int source_len() const { return static_cast<int>(source_buffer_.size()); }
+
+  const char* encoded_buffer() const { return encoded_buffer_.data(); }
+  int encoded_len() const { return static_cast<int>(encoded_buffer_.size()); }
+
+  scoped_ptr<Filter> filter_;
+
+ private:
+  MockFilterContext filter_context_;
+  std::string source_buffer_;
+  std::string encoded_buffer_;
+};
+
+// Basic scenario: decoding gzip data with big enough buffer.

[Randy Smith (Not in Mondays), 2015/12/07 22:27:28]

nit: Shouldn't this be "decoding *brotli* data ..."?

[eustas, 2015/12/08 11:31:31]

Done.

+TEST_F(BrotliUnitTest, DecodeBrotli) {
+  InitFilter();
+  memcpy(filter_->stream_buffer()->data(), encoded_buffer(), encoded_len());
+  filter_->FlushStreamBuffer(encoded_len());
+
+  char decode_buffer[kDefaultBufferSize];

[Randy Smith (Not in Mondays), 2015/12/07 22:27:28]

Suggestion: Put a DCHECK or ASSERT here that kDefaultBufferSize > source_len().

[eustas, 2015/12/08 11:31:31]

Done.

+  int decode_size = kDefaultBufferSize;
+  filter_->ReadData(decode_buffer, &decode_size);
+
+  // Compare the decoding result with source data
+  EXPECT_EQ(source_len(), decode_size);
+  EXPECT_EQ(memcmp(source_buffer(), decode_buffer, source_len()), 0);
+}
+
+// Tests we can call filter repeatedly to get all the data decoded.
+// To do that, we create a filter with a small buffer that can not hold all
+// the input data.
+TEST_F(BrotliUnitTest, DecodeWithSmallBuffer) {
+  InitFilterWithBufferSize(kSmallBufferSize);
+  EXPECT_EQ(kSmallBufferSize, filter_->stream_buffer_size());
+  DecodeAndCompareWithFilter(filter_.get(), source_buffer(), source_len(),
+                             encoded_buffer(), encoded_len(),
+                             kDefaultBufferSize);
+}
+
+// Tests we can still decode with just 1 byte buffer in the filter.
+// The purpose of this test: sometimes the filter will consume input without
+// generating output. Verify filter can handle it correctly.
+TEST_F(BrotliUnitTest, DecodeWithOneByteBuffer) {
+  InitFilterWithBufferSize(1);
+  EXPECT_EQ(1, filter_->stream_buffer_size());
+  DecodeAndCompareWithFilter(filter_.get(), source_buffer(), source_len(),
+                             encoded_buffer(), encoded_len(),
+                             kDefaultBufferSize);
+}
+
+// Tests we can decode when caller has small buffer to read out from filter.

[Randy Smith (Not in Mondays), 2015/12/07 22:27:28]

DecodeWithSmallBuffer tests small filter buffer + large output buffer.  This
test tests default filter buffer and small output buffer.  Most other tests, I
believe, test with default filter buffer and large output buffer.  How about a
test that tests with small filter buffer + small output buffer?  It's probably
fine (the single element buffer for both filter and output seems like it should
cover the same case) but it is an unexplored test option as best I can see.

[eustas, 2015/12/08 11:31:31]

The more tests the better. Added small/small test.

+TEST_F(BrotliUnitTest, DecodeWithSmallOutputBuffer) {
+  InitFilter();
+  DecodeAndCompareWithFilter(filter_.get(), source_buffer(), source_len(),
+                             encoded_buffer(), encoded_len(), kSmallBufferSize);
+}
+
+// Tests we can still decode with just 1 byte buffer in the filter and just 1
+// byte buffer in the caller.
+TEST_F(BrotliUnitTest, DecodeWithOneByteInputAndOutputBuffer) {
+  InitFilterWithBufferSize(1);
+  EXPECT_EQ(1, filter_->stream_buffer_size());
+  DecodeAndCompareWithFilter(filter_.get(), source_buffer(), source_len(),
+                             encoded_buffer(), encoded_len(), 1);
+}
+
+// Decoding deflate stream with corrupted data.
+TEST_F(BrotliUnitTest, DecodeCorruptedData) {
+  char corrupt_data[kDefaultBufferSize];
+  int corrupt_data_len = encoded_len();
+  memcpy(corrupt_data, encoded_buffer(), encoded_len());
+
+  int pos = corrupt_data_len / 2;
+  corrupt_data[pos] = !corrupt_data[pos];
+
+  // Decode the corrupted data with filter
+  InitFilter();
+  char corrupt_decode_buffer[kDefaultBufferSize];
+  int corrupt_decode_size = kDefaultBufferSize;
+
+  int code = DecodeAllWithFilter(filter_.get(), corrupt_data, corrupt_data_len,
+                                 corrupt_decode_buffer, &corrupt_decode_size);
+
+  // Expect failures
+  EXPECT_EQ(Filter::FILTER_ERROR, code);
+}
+
+// Decoding deflate stream with missing data.
+TEST_F(BrotliUnitTest, DecodeMissingData) {
+  char corrupt_data[kDefaultBufferSize];
+  int corrupt_data_len = encoded_len();
+  memcpy(corrupt_data, encoded_buffer(), encoded_len());
+
+  int pos = corrupt_data_len / 2;
+  int len = corrupt_data_len - pos - 1;
+  memmove(&corrupt_data[pos], &corrupt_data[pos + 1], len);
+  --corrupt_data_len;
+
+  // Decode the corrupted data with filter
+  InitFilter();
+  char corrupt_decode_buffer[kDefaultBufferSize];
+  int corrupt_decode_size = kDefaultBufferSize;
+
+  int code = DecodeAllWithFilter(filter_.get(), corrupt_data, corrupt_data_len,
+                                 corrupt_decode_buffer, &corrupt_decode_size);
+
+  // Expect failures
+  EXPECT_EQ(Filter::FILTER_ERROR, code);
+}
+
+}  // namespace net