// Copyright 2014 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 "net/spdy/hpack_huffman_table.h"
#include <bitset>
#include <string>
#include "base/logging.h"
#include "net/spdy/hpack_constants.h"
#include "net/spdy/hpack_input_stream.h"
#include "net/spdy/hpack_output_stream.h"
#include "net/spdy/spdy_test_utils.h"
#include "testing/gmock/include/gmock/gmock.h"
#include "testing/gtest/include/gtest/gtest.h"
using base::StringPiece;
using net::test::a2b_hex;
using std::string;
using testing::ElementsAre;
using testing::ElementsAreArray;
using testing::Pointwise;
namespace net {
namespace test {
typedef HpackHuffmanTable::DecodeEntry DecodeEntry;
typedef HpackHuffmanTable::DecodeTable DecodeTable;
class HpackHuffmanTablePeer {
public:
explicit HpackHuffmanTablePeer(const HpackHuffmanTable& table)
: table_(table) { }
const std::vector<uint32>& code_by_id() const {
return table_.code_by_id_;
}
const std::vector<uint8>& length_by_id() const {
return table_.length_by_id_;
}
const std::vector<DecodeTable>& decode_tables() const {
return table_.decode_tables_;
}
char pad_bits() const {
// Cast to match signed-ness of bits8().
return static_cast<char>(table_.pad_bits_);
}
uint16 failed_symbol_id() const {
return table_.failed_symbol_id_;
}
std::vector<DecodeEntry> decode_entries(const DecodeTable& decode_table) {
std::vector<DecodeEntry>::const_iterator begin =
table_.decode_entries_.begin() + decode_table.entries_offset;
return std::vector<DecodeEntry>(begin, begin + decode_table.size());
}
void DumpDecodeTable(const DecodeTable& table) {
std::vector<DecodeEntry> entries = decode_entries(table);
LOG(INFO) << "Table size " << (1 << table.indexed_length)
<< " prefix " << unsigned(table.prefix_length)
<< " indexed " << unsigned(table.indexed_length);
size_t i = 0;
while (i != table.size()) {
const DecodeEntry& entry = entries[i];
LOG(INFO) << i << ":"
<< " next_table " << unsigned(entry.next_table_index)
<< " length " << unsigned(entry.length)
<< " symbol " << unsigned(entry.symbol_id);
size_t j = 1;
for (; (i + j) != table.size(); j++) {
const DecodeEntry& next = entries[i + j];
if (next.next_table_index != entry.next_table_index ||
next.length != entry.length ||
next.symbol_id != entry.symbol_id)
break;
}
if (j > 1) {
LOG(INFO) << " (repeats " << j << " times)";
}
i += j;
}
}
private:
const HpackHuffmanTable& table_;
};
namespace {
class HpackHuffmanTableTest : public ::testing::Test {
protected:
HpackHuffmanTableTest()
: table_(),
peer_(table_) {}
string EncodeString(StringPiece input) {
string result;
HpackOutputStream output_stream;
table_.EncodeString(input, &output_stream);
output_stream.TakeString(&result);
// Verify EncodedSize() agrees with EncodeString().
EXPECT_EQ(result.size(), table_.EncodedSize(input));
return result;
}
HpackHuffmanTable table_;
HpackHuffmanTablePeer peer_;
};
MATCHER(DecodeEntryEq, "") {
const DecodeEntry& lhs = std::tr1::get<0>(arg);
const DecodeEntry& rhs = std::tr1::get<1>(arg);
return lhs.next_table_index == rhs.next_table_index &&
lhs.length == rhs.length &&
lhs.symbol_id == rhs.symbol_id;
}
uint32 bits32(const string& bitstring) {
return std::bitset<32>(bitstring).to_ulong();
}
char bits8(const string& bitstring) {
return static_cast<char>(std::bitset<8>(bitstring).to_ulong());
}
TEST_F(HpackHuffmanTableTest, InitializeHpackCode) {
std::vector<HpackHuffmanSymbol> code = HpackHuffmanCode();
EXPECT_TRUE(table_.Initialize(&code[0], code.size()));
EXPECT_TRUE(table_.IsInitialized());
EXPECT_EQ(peer_.pad_bits(), bits8("11111111")); // First 8 bits of EOS.
}
TEST_F(HpackHuffmanTableTest, InitializeEdgeCases) {
{
// Verify eight symbols can be encoded with 3 bits per symbol.
HpackHuffmanSymbol code[] = {
{bits32("00000000000000000000000000000000"), 3, 0},
{bits32("00100000000000000000000000000000"), 3, 1},
{bits32("01000000000000000000000000000000"), 3, 2},
{bits32("01100000000000000000000000000000"), 3, 3},
{bits32("10000000000000000000000000000000"), 3, 4},
{bits32("10100000000000000000000000000000"), 3, 5},
{bits32("11000000000000000000000000000000"), 3, 6},
{bits32("11100000000000000000000000000000"), 8, 7}};
HpackHuffmanTable table;
EXPECT_TRUE(table.Initialize(code, arraysize(code)));
}
{
// But using 2 bits with one symbol overflows the code.
HpackHuffmanSymbol code[] = {
{bits32("01000000000000000000000000000000"), 3, 0},
{bits32("01100000000000000000000000000000"), 3, 1},
{bits32("00000000000000000000000000000000"), 2, 2},
{bits32("10000000000000000000000000000000"), 3, 3},
{bits32("10100000000000000000000000000000"), 3, 4},
{bits32("11000000000000000000000000000000"), 3, 5},
{bits32("11100000000000000000000000000000"), 3, 6},
{bits32("00000000000000000000000000000000"), 8, 7}}; // Overflow.
HpackHuffmanTable table;
EXPECT_FALSE(table.Initialize(code, arraysize(code)));
EXPECT_EQ(7, HpackHuffmanTablePeer(table).failed_symbol_id());
}
{
// Verify four symbols can be encoded with incremental bits per symbol.
HpackHuffmanSymbol code[] = {
{bits32("00000000000000000000000000000000"), 1, 0},
{bits32("10000000000000000000000000000000"), 2, 1},
{bits32("11000000000000000000000000000000"), 3, 2},
{bits32("11100000000000000000000000000000"), 8, 3}};
HpackHuffmanTable table;
EXPECT_TRUE(table.Initialize(code, arraysize(code)));
}
{
// But repeating a length overflows the code.
HpackHuffmanSymbol code[] = {
{bits32("00000000000000000000000000000000"), 1, 0},
{bits32("10000000000000000000000000000000"), 2, 1},
{bits32("11000000000000000000000000000000"), 2, 2},
{bits32("00000000000000000000000000000000"), 8, 3}}; // Overflow.
HpackHuffmanTable table;
EXPECT_FALSE(table.Initialize(code, arraysize(code)));
EXPECT_EQ(3, HpackHuffmanTablePeer(table).failed_symbol_id());
}
{
// Symbol IDs must be assigned sequentially with no gaps.
HpackHuffmanSymbol code[] = {
{bits32("00000000000000000000000000000000"), 1, 0},
{bits32("10000000000000000000000000000000"), 2, 1},
{bits32("11000000000000000000000000000000"), 3, 1}, // Repeat.
{bits32("11100000000000000000000000000000"), 8, 3}};
HpackHuffmanTable table;
EXPECT_FALSE(table.Initialize(code, arraysize(code)));
EXPECT_EQ(2, HpackHuffmanTablePeer(table).failed_symbol_id());
}
{
// Canonical codes must begin with zero.
HpackHuffmanSymbol code[] = {
{bits32("10000000000000000000000000000000"), 4, 0},
{bits32("10010000000000000000000000000000"), 4, 1},
{bits32("10100000000000000000000000000000"), 4, 2},
{bits32("10110000000000000000000000000000"), 8, 3}};
HpackHuffmanTable table;
EXPECT_FALSE(table.Initialize(code, arraysize(code)));
EXPECT_EQ(0, HpackHuffmanTablePeer(table).failed_symbol_id());
}
{
// Codes must match the expected canonical sequence.
HpackHuffmanSymbol code[] = {
{bits32("00000000000000000000000000000000"), 2, 0},
{bits32("01000000000000000000000000000000"), 2, 1},
{bits32("11000000000000000000000000000000"), 2, 2}, // Not canonical.
{bits32("10000000000000000000000000000000"), 8, 3}};
HpackHuffmanTable table;
EXPECT_FALSE(table.Initialize(code, arraysize(code)));
EXPECT_EQ(2, HpackHuffmanTablePeer(table).failed_symbol_id());
}
{
// At least one code must have a length of 8 bits (to ensure pad-ability).
HpackHuffmanSymbol code[] = {
{bits32("00000000000000000000000000000000"), 1, 0},
{bits32("10000000000000000000000000000000"), 2, 1},
{bits32("11000000000000000000000000000000"), 3, 2},
{bits32("11100000000000000000000000000000"), 7, 3}};
HpackHuffmanTable table;
EXPECT_FALSE(table.Initialize(code, arraysize(code)));
}
}
TEST_F(HpackHuffmanTableTest, ValidateInternalsWithSmallCode) {
HpackHuffmanSymbol code[] = {
{bits32("01100000000000000000000000000000"), 4, 0}, // 3rd.
{bits32("01110000000000000000000000000000"), 4, 1}, // 4th.
{bits32("00000000000000000000000000000000"), 2, 2}, // 1st assigned code.
{bits32("01000000000000000000000000000000"), 3, 3}, // 2nd.
{bits32("10000000000000000000000000000000"), 5, 4}, // 5th.
{bits32("10001000000000000000000000000000"), 5, 5}, // 6th.
{bits32("10011000000000000000000000000000"), 8, 6}, // 8th.
{bits32("10010000000000000000000000000000"), 5, 7}}; // 7th.
EXPECT_TRUE(table_.Initialize(code, arraysize(code)));
EXPECT_THAT(peer_.code_by_id(), ElementsAre(
bits32("01100000000000000000000000000000"),
bits32("01110000000000000000000000000000"),
bits32("00000000000000000000000000000000"),
bits32("01000000000000000000000000000000"),
bits32("10000000000000000000000000000000"),
bits32("10001000000000000000000000000000"),
bits32("10011000000000000000000000000000"),
bits32("10010000000000000000000000000000")));
EXPECT_THAT(peer_.length_by_id(), ElementsAre(
4, 4, 2, 3, 5, 5, 8, 5));
EXPECT_EQ(1u, peer_.decode_tables().size());
{
std::vector<DecodeEntry> expected;
expected.resize(128, DecodeEntry(0, 2, 2)); // Fills 128.
expected.resize(192, DecodeEntry(0, 3, 3)); // Fills 64.
expected.resize(224, DecodeEntry(0, 4, 0)); // Fills 32.
expected.resize(256, DecodeEntry(0, 4, 1)); // Fills 32.
expected.resize(272, DecodeEntry(0, 5, 4)); // Fills 16.
expected.resize(288, DecodeEntry(0, 5, 5)); // Fills 16.
expected.resize(304, DecodeEntry(0, 5, 7)); // Fills 16.
expected.resize(306, DecodeEntry(0, 8, 6)); // Fills 2.
expected.resize(512, DecodeEntry()); // Remainder is empty.
EXPECT_THAT(peer_.decode_entries(peer_.decode_tables()[0]),
Pointwise(DecodeEntryEq(), expected));
}
EXPECT_EQ(bits8("10011000"), peer_.pad_bits());
char input_storage[] = {2, 3, 2, 7, 4};
StringPiece input(input_storage, arraysize(input_storage));
// By symbol: (2) 00 (3) 010 (2) 00 (7) 10010 (4) 10000 (6 as pad) 1001100.
char expect_storage[] = {
bits8("00010001"),
bits8("00101000"),
bits8("01001100")};
StringPiece expect(expect_storage, arraysize(expect_storage));
string buffer_in = EncodeString(input);
EXPECT_EQ(expect, buffer_in);
string buffer_out;
HpackInputStream input_stream(kuint32max, buffer_in);
EXPECT_TRUE(table_.DecodeString(&input_stream, input.size(), &buffer_out));
EXPECT_EQ(buffer_out, input);
}
TEST_F(HpackHuffmanTableTest, ValidateMultiLevelDecodeTables) {
HpackHuffmanSymbol code[] = {
{bits32("00000000000000000000000000000000"), 6, 0},
{bits32("00000100000000000000000000000000"), 6, 1},
{bits32("00001000000000000000000000000000"), 11, 2},
{bits32("00001000001000000000000000000000"), 11, 3},
{bits32("00001000010000000000000000000000"), 12, 4},
};
EXPECT_TRUE(table_.Initialize(code, arraysize(code)));
EXPECT_EQ(2u, peer_.decode_tables().size());
{
std::vector<DecodeEntry> expected;
expected.resize(8, DecodeEntry(0, 6, 0)); // Fills 8.
expected.resize(16, DecodeEntry(0, 6, 1)); // Fills 8.
expected.resize(17, DecodeEntry(1, 12, 0)); // Pointer. Fills 1.
expected.resize(512, DecodeEntry()); // Remainder is empty.
const DecodeTable& decode_table = peer_.decode_tables()[0];
EXPECT_EQ(decode_table.prefix_length, 0);
EXPECT_EQ(decode_table.indexed_length, 9);
EXPECT_THAT(peer_.decode_entries(decode_table),
Pointwise(DecodeEntryEq(), expected));
}
{
std::vector<DecodeEntry> expected;
expected.resize(2, DecodeEntry(1, 11, 2)); // Fills 2.
expected.resize(4, DecodeEntry(1, 11, 3)); // Fills 2.
expected.resize(5, DecodeEntry(1, 12, 4)); // Fills 1.
expected.resize(8, DecodeEntry()); // Remainder is empty.
const DecodeTable& decode_table = peer_.decode_tables()[1];
EXPECT_EQ(decode_table.prefix_length, 9);
EXPECT_EQ(decode_table.indexed_length, 3);
EXPECT_THAT(peer_.decode_entries(decode_table),
Pointwise(DecodeEntryEq(), expected));
}
EXPECT_EQ(bits8("00001000"), peer_.pad_bits());
}
TEST_F(HpackHuffmanTableTest, DecodeWithBadInput) {
HpackHuffmanSymbol code[] = {
{bits32("01100000000000000000000000000000"), 4, 0},
{bits32("01110000000000000000000000000000"), 4, 1},
{bits32("00000000000000000000000000000000"), 2, 2},
{bits32("01000000000000000000000000000000"), 3, 3},
{bits32("10000000000000000000000000000000"), 5, 4},
{bits32("10001000000000000000000000000000"), 5, 5},
{bits32("10011000000000000000000000000000"), 6, 6},
{bits32("10010000000000000000000000000000"), 5, 7},
{bits32("10011100000000000000000000000000"), 16, 8}};
EXPECT_TRUE(table_.Initialize(code, arraysize(code)));
string buffer;
const size_t capacity = 4;
{
// This example works: (2) 00 (3) 010 (2) 00 (6) 100110 (pad) 100.
char input_storage[] = {bits8("00010001"), bits8("00110100")};
StringPiece input(input_storage, arraysize(input_storage));
HpackInputStream input_stream(kuint32max, input);
EXPECT_TRUE(table_.DecodeString(&input_stream, capacity, &buffer));
EXPECT_EQ(buffer, "\x02\x03\x02\x06");
}
{
// Expect to fail on an invalid code prefix.
// (2) 00 (3) 010 (2) 00 (too-large) 101000 (pad) 100.
char input_storage[] = {bits8("00010001"), bits8("01000111")};
StringPiece input(input_storage, arraysize(input_storage));
HpackInputStream input_stream(kuint32max, input);
EXPECT_FALSE(table_.DecodeString(&input_stream, capacity, &buffer));
EXPECT_EQ(buffer, "\x02\x03\x02");
}
{
// Repeat the shortest 0b00 code to overflow |buffer|. Expect to fail.
std::vector<char> input_storage(1 + capacity / 4, '\0');
StringPiece input(&input_storage[0], input_storage.size());
HpackInputStream input_stream(kuint32max, input);
EXPECT_FALSE(table_.DecodeString(&input_stream, capacity, &buffer));
std::vector<char> expected(capacity, '\x02');
EXPECT_THAT(buffer, ElementsAreArray(expected));
EXPECT_EQ(capacity, buffer.size());
}
{
// Expect to fail if more than a byte of unconsumed input remains.
// (6) 100110 (8 truncated) 1001110000
char input_storage[] = {bits8("10011010"), bits8("01110000")};
StringPiece input(input_storage, arraysize(input_storage));
HpackInputStream input_stream(kuint32max, input);
EXPECT_FALSE(table_.DecodeString(&input_stream, capacity, &buffer));
EXPECT_EQ(buffer, "\x06");
}
}
TEST_F(HpackHuffmanTableTest, SpecRequestExamples) {
std::vector<HpackHuffmanSymbol> code = HpackHuffmanCode();
EXPECT_TRUE(table_.Initialize(&code[0], code.size()));
string buffer;
string test_table[] = {
a2b_hex("f1e3c2e5f23a6ba0ab90f4ff"),
"www.example.com",
a2b_hex("a8eb10649cbf"),
"no-cache",
a2b_hex("25a849e95ba97d7f"),
"custom-key",
a2b_hex("25a849e95bb8e8b4bf"),
"custom-value",
};
// Round-trip each test example.
for (size_t i = 0; i != arraysize(test_table); i += 2) {
const string& encodedFixture(test_table[i]);
const string& decodedFixture(test_table[i+1]);
HpackInputStream input_stream(kuint32max, encodedFixture);
EXPECT_TRUE(table_.DecodeString(&input_stream, decodedFixture.size(),
&buffer));
EXPECT_EQ(decodedFixture, buffer);
buffer = EncodeString(decodedFixture);
EXPECT_EQ(encodedFixture, buffer);
}
}
TEST_F(HpackHuffmanTableTest, SpecResponseExamples) {
std::vector<HpackHuffmanSymbol> code = HpackHuffmanCode();
EXPECT_TRUE(table_.Initialize(&code[0], code.size()));
string buffer;
string test_table[] = {
a2b_hex("6402"),
"302",
a2b_hex("aec3771a4b"),
"private",
a2b_hex("d07abe941054d444a8200595040b8166"
"e082a62d1bff"),
"Mon, 21 Oct 2013 20:13:21 GMT",
a2b_hex("9d29ad171863c78f0b97c8e9ae82ae43"
"d3"),
"https://www.example.com",
a2b_hex("94e7821dd7f2e6c7b335dfdfcd5b3960"
"d5af27087f3672c1ab270fb5291f9587"
"316065c003ed4ee5b1063d5007"),
"foo=ASDJKHQKBZXOQWEOPIUAXQWEOIU; max-age=3600; version=1",
};
// Round-trip each test example.
for (size_t i = 0; i != arraysize(test_table); i += 2) {
const string& encodedFixture(test_table[i]);
const string& decodedFixture(test_table[i+1]);
HpackInputStream input_stream(kuint32max, encodedFixture);
EXPECT_TRUE(table_.DecodeString(&input_stream, decodedFixture.size(),
&buffer));
EXPECT_EQ(decodedFixture, buffer);
buffer = EncodeString(decodedFixture);
EXPECT_EQ(encodedFixture, buffer);
}
}
TEST_F(HpackHuffmanTableTest, RoundTripIndvidualSymbols) {
std::vector<HpackHuffmanSymbol> code = HpackHuffmanCode();
EXPECT_TRUE(table_.Initialize(&code[0], code.size()));
for (size_t i = 0; i != 256; i++) {
char c = static_cast<char>(i);
char storage[3] = {c, c, c};
StringPiece input(storage, arraysize(storage));
string buffer_in = EncodeString(input);
string buffer_out;
HpackInputStream input_stream(kuint32max, buffer_in);
EXPECT_TRUE(table_.DecodeString(&input_stream, input.size(), &buffer_out));
EXPECT_EQ(input, buffer_out);
}
}
TEST_F(HpackHuffmanTableTest, RoundTripSymbolSequence) {
std::vector<HpackHuffmanSymbol> code = HpackHuffmanCode();
EXPECT_TRUE(table_.Initialize(&code[0], code.size()));
char storage[512];
for (size_t i = 0; i != 256; i++) {
storage[i] = static_cast<char>(i);
storage[511 - i] = static_cast<char>(i);
}
StringPiece input(storage, arraysize(storage));
string buffer_in = EncodeString(input);
string buffer_out;
HpackInputStream input_stream(kuint32max, buffer_in);
EXPECT_TRUE(table_.DecodeString(&input_stream, input.size(), &buffer_out));
EXPECT_EQ(input, buffer_out);
}
TEST_F(HpackHuffmanTableTest, EncodedSizeAgreesWithEncodeString) {
std::vector<HpackHuffmanSymbol> code = HpackHuffmanCode();
EXPECT_TRUE(table_.Initialize(&code[0], code.size()));
string test_table[] = {
"",
"Mon, 21 Oct 2013 20:13:21 GMT",
"https://www.example.com",
"foo=ASDJKHQKBZXOQWEOPIUAXQWEOIU; max-age=3600; version=1",
string(1, '\0'),
string("foo\0bar", 7),
string(256, '\0'),
};
for (size_t i = 0; i != 256; ++i) {
// Expand last |test_table| entry to cover all codes.
test_table[arraysize(test_table)-1][i] = static_cast<char>(i);
}
HpackOutputStream output_stream;
string encoding;
for (size_t i = 0; i != arraysize(test_table); ++i) {
table_.EncodeString(test_table[i], &output_stream);
output_stream.TakeString(&encoding);
EXPECT_EQ(encoding.size(), table_.EncodedSize(test_table[i]));
}
}
} // namespace
} // namespace test
} // namespace net