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abseil-cpp/absl/strings/cord_test.cc

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// Copyright 2020 The Abseil Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include "absl/strings/cord.h"
#include <algorithm>
#include <climits>
#include <cstdio>
#include <iterator>
#include <map>
#include <numeric>
#include <random>
#include <sstream>
#include <type_traits>
#include <utility>
#include <vector>
#include "gmock/gmock.h"
#include "gtest/gtest.h"
#include "absl/base/casts.h"
#include "absl/base/config.h"
#include "absl/base/internal/endian.h"
#include "absl/base/internal/raw_logging.h"
#include "absl/base/macros.h"
#include "absl/container/fixed_array.h"
#include "absl/hash/hash.h"
#include "absl/random/random.h"
#include "absl/strings/cord_test_helpers.h"
#include "absl/strings/cordz_test_helpers.h"
#include "absl/strings/match.h"
#include "absl/strings/str_cat.h"
#include "absl/strings/str_format.h"
#include "absl/strings/string_view.h"
// convenience local constants
static constexpr auto FLAT = absl::cord_internal::FLAT;
static constexpr auto MAX_FLAT_TAG = absl::cord_internal::MAX_FLAT_TAG;
typedef std::mt19937_64 RandomEngine;
using absl::cord_internal::CordRep;
using absl::cord_internal::CordRepBtree;
using absl::cord_internal::CordRepConcat;
using absl::cord_internal::CordRepCrc;
using absl::cord_internal::CordRepExternal;
using absl::cord_internal::CordRepFlat;
using absl::cord_internal::CordRepSubstring;
using absl::cord_internal::CordzUpdateTracker;
using absl::cord_internal::kFlatOverhead;
using absl::cord_internal::kMaxFlatLength;
static std::string RandomLowercaseString(RandomEngine* rng);
static std::string RandomLowercaseString(RandomEngine* rng, size_t length);
static int GetUniformRandomUpTo(RandomEngine* rng, int upper_bound) {
if (upper_bound > 0) {
std::uniform_int_distribution<int> uniform(0, upper_bound - 1);
return uniform(*rng);
} else {
return 0;
}
}
static size_t GetUniformRandomUpTo(RandomEngine* rng, size_t upper_bound) {
if (upper_bound > 0) {
std::uniform_int_distribution<size_t> uniform(0, upper_bound - 1);
return uniform(*rng);
} else {
return 0;
}
}
static int32_t GenerateSkewedRandom(RandomEngine* rng, int max_log) {
const uint32_t base = (*rng)() % (max_log + 1);
const uint32_t mask = ((base < 32) ? (1u << base) : 0u) - 1u;
return (*rng)() & mask;
}
static std::string RandomLowercaseString(RandomEngine* rng) {
int length;
std::bernoulli_distribution one_in_1k(0.001);
std::bernoulli_distribution one_in_10k(0.0001);
// With low probability, make a large fragment
if (one_in_10k(*rng)) {
length = GetUniformRandomUpTo(rng, 1048576);
} else if (one_in_1k(*rng)) {
length = GetUniformRandomUpTo(rng, 10000);
} else {
length = GenerateSkewedRandom(rng, 10);
}
return RandomLowercaseString(rng, length);
}
static std::string RandomLowercaseString(RandomEngine* rng, size_t length) {
std::string result(length, '\0');
std::uniform_int_distribution<int> chars('a', 'z');
std::generate(result.begin(), result.end(),
[&]() { return static_cast<char>(chars(*rng)); });
return result;
}
static void DoNothing(absl::string_view /* data */, void* /* arg */) {}
static void DeleteExternalString(absl::string_view data, void* arg) {
std::string* s = reinterpret_cast<std::string*>(arg);
EXPECT_EQ(data, *s);
delete s;
}
// Add "s" to *dst via `MakeCordFromExternal`
static void AddExternalMemory(absl::string_view s, absl::Cord* dst) {
std::string* str = new std::string(s.data(), s.size());
dst->Append(absl::MakeCordFromExternal(*str, [str](absl::string_view data) {
DeleteExternalString(data, str);
}));
}
static void DumpGrowth() {
absl::Cord str;
for (int i = 0; i < 1000; i++) {
char c = 'a' + i % 26;
str.Append(absl::string_view(&c, 1));
}
}
// Make a Cord with some number of fragments. Return the size (in bytes)
// of the smallest fragment.
static size_t AppendWithFragments(const std::string& s, RandomEngine* rng,
absl::Cord* cord) {
size_t j = 0;
const size_t max_size = s.size() / 5; // Make approx. 10 fragments
size_t min_size = max_size; // size of smallest fragment
while (j < s.size()) {
size_t N = 1 + GetUniformRandomUpTo(rng, max_size);
if (N > (s.size() - j)) {
N = s.size() - j;
}
if (N < min_size) {
min_size = N;
}
std::bernoulli_distribution coin_flip(0.5);
if (coin_flip(*rng)) {
// Grow by adding an external-memory.
AddExternalMemory(absl::string_view(s.data() + j, N), cord);
} else {
cord->Append(absl::string_view(s.data() + j, N));
}
j += N;
}
return min_size;
}
// Add an external memory that contains the specified std::string to cord
static void AddNewStringBlock(const std::string& str, absl::Cord* dst) {
char* data = new char[str.size()];
memcpy(data, str.data(), str.size());
dst->Append(absl::MakeCordFromExternal(
absl::string_view(data, str.size()),
[](absl::string_view s) { delete[] s.data(); }));
}
// Make a Cord out of many different types of nodes.
static absl::Cord MakeComposite() {
absl::Cord cord;
cord.Append("the");
AddExternalMemory(" quick brown", &cord);
AddExternalMemory(" fox jumped", &cord);
absl::Cord full(" over");
AddExternalMemory(" the lazy", &full);
AddNewStringBlock(" dog slept the whole day away", &full);
absl::Cord substring = full.Subcord(0, 18);
// Make substring long enough to defeat the copying fast path in Append.
substring.Append(std::string(1000, '.'));
cord.Append(substring);
cord = cord.Subcord(0, cord.size() - 998); // Remove most of extra junk
return cord;
}
namespace absl {
ABSL_NAMESPACE_BEGIN
class CordTestPeer {
public:
static void ForEachChunk(
const Cord& c, absl::FunctionRef<void(absl::string_view)> callback) {
c.ForEachChunk(callback);
}
static bool IsTree(const Cord& c) { return c.contents_.is_tree(); }
static CordRep* Tree(const Cord& c) { return c.contents_.tree(); }
static cord_internal::CordzInfo* GetCordzInfo(const Cord& c) {
return c.contents_.cordz_info();
}
static Cord MakeSubstring(Cord src, size_t offset, size_t length) {
ABSL_RAW_CHECK(src.contents_.is_tree(), "Can not be inlined");
ABSL_RAW_CHECK(src.ExpectedChecksum() == absl::nullopt,
"Can not be hardened");
Cord cord;
auto* tree = cord_internal::SkipCrcNode(src.contents_.tree());
auto* rep = CordRepSubstring::Create(CordRep::Ref(tree), offset, length);
cord.contents_.EmplaceTree(rep, CordzUpdateTracker::kSubCord);
return cord;
}
};
ABSL_NAMESPACE_END
} // namespace absl
// The CordTest fixture runs all tests with and without Cord Btree enabled,
// and with our without expected CRCs being set on the subject Cords.
class CordTest : public testing::TestWithParam<int> {
public:
// Returns true if test is running with btree enabled.
bool UseCrc() const { return GetParam() == 2 || GetParam() == 3; }
void MaybeHarden(absl::Cord& c) {
if (UseCrc()) {
c.SetExpectedChecksum(1);
}
}
absl::Cord MaybeHardened(absl::Cord c) {
MaybeHarden(c);
return c;
}
// Returns human readable string representation of the test parameter.
static std::string ToString(testing::TestParamInfo<int> param) {
switch (param.param) {
case 0:
return "Btree";
case 1:
return "BtreeHardened";
default:
assert(false);
return "???";
}
}
};
INSTANTIATE_TEST_SUITE_P(WithParam, CordTest, testing::Values(0, 1),
CordTest::ToString);
TEST(CordRepFlat, AllFlatCapacities) {
// Explicitly and redundantly assert built-in min/max limits
static_assert(absl::cord_internal::kFlatOverhead < 32, "");
static_assert(absl::cord_internal::kMinFlatSize == 32, "");
static_assert(absl::cord_internal::kMaxLargeFlatSize == 256 << 10, "");
EXPECT_EQ(absl::cord_internal::TagToAllocatedSize(FLAT), 32);
EXPECT_EQ(absl::cord_internal::TagToAllocatedSize(MAX_FLAT_TAG), 256 << 10);
// Verify all tags to map perfectly back and forth, and
// that sizes are monotonically increasing.
size_t last_size = 0;
for (int tag = FLAT; tag <= MAX_FLAT_TAG; ++tag) {
size_t size = absl::cord_internal::TagToAllocatedSize(tag);
ASSERT_GT(size, last_size);
ASSERT_EQ(absl::cord_internal::TagToAllocatedSize(tag), size);
last_size = size;
}
// All flat size from 32 - 512 are 8 byte granularity
for (size_t size = 32; size <= 512; size += 8) {
ASSERT_EQ(absl::cord_internal::RoundUpForTag(size), size);
uint8_t tag = absl::cord_internal::AllocatedSizeToTag(size);
ASSERT_EQ(absl::cord_internal::TagToAllocatedSize(tag), size);
}
// All flat sizes from 512 - 8192 are 64 byte granularity
for (size_t size = 512; size <= 8192; size += 64) {
ASSERT_EQ(absl::cord_internal::RoundUpForTag(size), size);
uint8_t tag = absl::cord_internal::AllocatedSizeToTag(size);
ASSERT_EQ(absl::cord_internal::TagToAllocatedSize(tag), size);
}
// All flat sizes from 8KB to 256KB are 4KB granularity
for (size_t size = 8192; size <= 256 * 1024; size += 4 * 1024) {
ASSERT_EQ(absl::cord_internal::RoundUpForTag(size), size);
uint8_t tag = absl::cord_internal::AllocatedSizeToTag(size);
ASSERT_EQ(absl::cord_internal::TagToAllocatedSize(tag), size);
}
}
TEST(CordRepFlat, MaxFlatSize) {
CordRepFlat* flat = CordRepFlat::New(kMaxFlatLength);
EXPECT_EQ(flat->Capacity(), kMaxFlatLength);
CordRep::Unref(flat);
flat = CordRepFlat::New(kMaxFlatLength * 4);
EXPECT_EQ(flat->Capacity(), kMaxFlatLength);
CordRep::Unref(flat);
}
TEST(CordRepFlat, MaxLargeFlatSize) {
const size_t size = 256 * 1024 - kFlatOverhead;
CordRepFlat* flat = CordRepFlat::New(CordRepFlat::Large(), size);
EXPECT_GE(flat->Capacity(), size);
CordRep::Unref(flat);
}
TEST(CordRepFlat, AllFlatSizes) {
const size_t kMaxSize = 256 * 1024;
for (size_t size = 32; size <= kMaxSize; size *=2) {
const size_t length = size - kFlatOverhead - 1;
CordRepFlat* flat = CordRepFlat::New(CordRepFlat::Large(), length);
EXPECT_GE(flat->Capacity(), length);
memset(flat->Data(), 0xCD, flat->Capacity());
CordRep::Unref(flat);
}
}
TEST_P(CordTest, AllFlatSizes) {
using absl::strings_internal::CordTestAccess;
for (size_t s = 0; s < CordTestAccess::MaxFlatLength(); s++) {
// Make a string of length s.
std::string src;
while (src.size() < s) {
src.push_back('a' + (src.size() % 26));
}
absl::Cord dst(src);
MaybeHarden(dst);
EXPECT_EQ(std::string(dst), src) << s;
}
}
// We create a Cord at least 128GB in size using the fact that Cords can
// internally reference-count; thus the Cord is enormous without actually
// consuming very much memory.
TEST_P(CordTest, GigabyteCordFromExternal) {
const size_t one_gig = 1024U * 1024U * 1024U;
size_t max_size = 2 * one_gig;
if (sizeof(max_size) > 4) max_size = 128 * one_gig;
size_t length = 128 * 1024;
char* data = new char[length];
absl::Cord from = absl::MakeCordFromExternal(
absl::string_view(data, length),
[](absl::string_view sv) { delete[] sv.data(); });
// This loop may seem odd due to its combination of exponential doubling of
// size and incremental size increases. We do it incrementally to be sure the
// Cord will need rebalancing and will exercise code that, in the past, has
// caused crashes in production. We grow exponentially so that the code will
// execute in a reasonable amount of time.
absl::Cord c;
c.Append(from);
while (c.size() < max_size) {
c.Append(c);
c.Append(from);
c.Append(from);
c.Append(from);
c.Append(from);
MaybeHarden(c);
}
for (int i = 0; i < 1024; ++i) {
c.Append(from);
}
ABSL_RAW_LOG(INFO, "Made a Cord with %zu bytes!", c.size());
// Note: on a 32-bit build, this comes out to 2,818,048,000 bytes.
// Note: on a 64-bit build, this comes out to 171,932,385,280 bytes.
}
static absl::Cord MakeExternalCord(int size) {
char* buffer = new char[size];
memset(buffer, 'x', size);
absl::Cord cord;
cord.Append(absl::MakeCordFromExternal(
absl::string_view(buffer, size),
[](absl::string_view s) { delete[] s.data(); }));
return cord;
}
// Extern to fool clang that this is not constant. Needed to suppress
// a warning of unsafe code we want to test.
extern bool my_unique_true_boolean;
bool my_unique_true_boolean = true;
TEST_P(CordTest, Assignment) {
absl::Cord x(absl::string_view("hi there"));
absl::Cord y(x);
MaybeHarden(y);
ASSERT_EQ(x.ExpectedChecksum(), absl::nullopt);
ASSERT_EQ(std::string(x), "hi there");
ASSERT_EQ(std::string(y), "hi there");
ASSERT_TRUE(x == y);
ASSERT_TRUE(x <= y);
ASSERT_TRUE(y <= x);
x = absl::string_view("foo");
ASSERT_EQ(std::string(x), "foo");
ASSERT_EQ(std::string(y), "hi there");
ASSERT_TRUE(x < y);
ASSERT_TRUE(y > x);
ASSERT_TRUE(x != y);
ASSERT_TRUE(x <= y);
ASSERT_TRUE(y >= x);
x = "foo";
ASSERT_EQ(x, "foo");
// Test that going from inline rep to tree we don't leak memory.
std::vector<std::pair<absl::string_view, absl::string_view>>
test_string_pairs = {{"hi there", "foo"},
{"loooooong coooooord", "short cord"},
{"short cord", "loooooong coooooord"},
{"loooooong coooooord1", "loooooong coooooord2"}};
for (std::pair<absl::string_view, absl::string_view> test_strings :
test_string_pairs) {
absl::Cord tmp(test_strings.first);
absl::Cord z(std::move(tmp));
ASSERT_EQ(std::string(z), test_strings.first);
tmp = test_strings.second;
z = std::move(tmp);
ASSERT_EQ(std::string(z), test_strings.second);
}
{
// Test that self-move assignment doesn't crash/leak.
// Do not write such code!
absl::Cord my_small_cord("foo");
absl::Cord my_big_cord("loooooong coooooord");
// Bypass clang's warning on self move-assignment.
absl::Cord* my_small_alias =
my_unique_true_boolean ? &my_small_cord : &my_big_cord;
absl::Cord* my_big_alias =
!my_unique_true_boolean ? &my_small_cord : &my_big_cord;
*my_small_alias = std::move(my_small_cord);
*my_big_alias = std::move(my_big_cord);
// my_small_cord and my_big_cord are in an unspecified but valid
// state, and will be correctly destroyed here.
}
}
TEST_P(CordTest, StartsEndsWith) {
absl::Cord x(absl::string_view("abcde"));
MaybeHarden(x);
absl::Cord empty("");
ASSERT_TRUE(x.StartsWith(absl::Cord("abcde")));
ASSERT_TRUE(x.StartsWith(absl::Cord("abc")));
ASSERT_TRUE(x.StartsWith(absl::Cord("")));
ASSERT_TRUE(empty.StartsWith(absl::Cord("")));
ASSERT_TRUE(x.EndsWith(absl::Cord("abcde")));
ASSERT_TRUE(x.EndsWith(absl::Cord("cde")));
ASSERT_TRUE(x.EndsWith(absl::Cord("")));
ASSERT_TRUE(empty.EndsWith(absl::Cord("")));
ASSERT_TRUE(!x.StartsWith(absl::Cord("xyz")));
ASSERT_TRUE(!empty.StartsWith(absl::Cord("xyz")));
ASSERT_TRUE(!x.EndsWith(absl::Cord("xyz")));
ASSERT_TRUE(!empty.EndsWith(absl::Cord("xyz")));
ASSERT_TRUE(x.StartsWith("abcde"));
ASSERT_TRUE(x.StartsWith("abc"));
ASSERT_TRUE(x.StartsWith(""));
ASSERT_TRUE(empty.StartsWith(""));
ASSERT_TRUE(x.EndsWith("abcde"));
ASSERT_TRUE(x.EndsWith("cde"));
ASSERT_TRUE(x.EndsWith(""));
ASSERT_TRUE(empty.EndsWith(""));
ASSERT_TRUE(!x.StartsWith("xyz"));
ASSERT_TRUE(!empty.StartsWith("xyz"));
ASSERT_TRUE(!x.EndsWith("xyz"));
ASSERT_TRUE(!empty.EndsWith("xyz"));
}
TEST_P(CordTest, Subcord) {
RandomEngine rng(GTEST_FLAG_GET(random_seed));
const std::string s = RandomLowercaseString(&rng, 1024);
absl::Cord a;
AppendWithFragments(s, &rng, &a);
MaybeHarden(a);
ASSERT_EQ(s, std::string(a));
// Check subcords of a, from a variety of interesting points.
std::set<size_t> positions;
for (int i = 0; i <= 32; ++i) {
positions.insert(i);
positions.insert(i * 32 - 1);
positions.insert(i * 32);
positions.insert(i * 32 + 1);
positions.insert(a.size() - i);
}
positions.insert(237);
positions.insert(732);
for (size_t pos : positions) {
if (pos > a.size()) continue;
for (size_t end_pos : positions) {
if (end_pos < pos || end_pos > a.size()) continue;
absl::Cord sa = a.Subcord(pos, end_pos - pos);
ASSERT_EQ(absl::string_view(s).substr(pos, end_pos - pos),
std::string(sa))
<< a;
if (pos != 0 || end_pos != a.size()) {
ASSERT_EQ(sa.ExpectedChecksum(), absl::nullopt);
}
}
}
// Do the same thing for an inline cord.
const std::string sh = "short";
absl::Cord c(sh);
for (size_t pos = 0; pos <= sh.size(); ++pos) {
for (size_t n = 0; n <= sh.size() - pos; ++n) {
absl::Cord sc = c.Subcord(pos, n);
ASSERT_EQ(sh.substr(pos, n), std::string(sc)) << c;
}
}
// Check subcords of subcords.
absl::Cord sa = a.Subcord(0, a.size());
std::string ss = s.substr(0, s.size());
while (sa.size() > 1) {
sa = sa.Subcord(1, sa.size() - 2);
ss = ss.substr(1, ss.size() - 2);
ASSERT_EQ(ss, std::string(sa)) << a;
if (HasFailure()) break; // halt cascade
}
// It is OK to ask for too much.
sa = a.Subcord(0, a.size() + 1);
EXPECT_EQ(s, std::string(sa));
// It is OK to ask for something beyond the end.
sa = a.Subcord(a.size() + 1, 0);
EXPECT_TRUE(sa.empty());
sa = a.Subcord(a.size() + 1, 1);
EXPECT_TRUE(sa.empty());
}
TEST_P(CordTest, Swap) {
absl::string_view a("Dexter");
absl::string_view b("Mandark");
absl::Cord x(a);
absl::Cord y(b);
MaybeHarden(x);
swap(x, y);
if (UseCrc()) {
ASSERT_EQ(x.ExpectedChecksum(), absl::nullopt);
ASSERT_EQ(y.ExpectedChecksum(), 1);
}
ASSERT_EQ(x, absl::Cord(b));
ASSERT_EQ(y, absl::Cord(a));
x.swap(y);
if (UseCrc()) {
ASSERT_EQ(x.ExpectedChecksum(), 1);
ASSERT_EQ(y.ExpectedChecksum(), absl::nullopt);
}
ASSERT_EQ(x, absl::Cord(a));
ASSERT_EQ(y, absl::Cord(b));
}
static void VerifyCopyToString(const absl::Cord& cord) {
std::string initially_empty;
absl::CopyCordToString(cord, &initially_empty);
EXPECT_EQ(initially_empty, cord);
constexpr size_t kInitialLength = 1024;
std::string has_initial_contents(kInitialLength, 'x');
const char* address_before_copy = has_initial_contents.data();
absl::CopyCordToString(cord, &has_initial_contents);
EXPECT_EQ(has_initial_contents, cord);
if (cord.size() <= kInitialLength) {
EXPECT_EQ(has_initial_contents.data(), address_before_copy)
<< "CopyCordToString allocated new string storage; "
"has_initial_contents = \""
<< has_initial_contents << "\"";
}
}
TEST_P(CordTest, CopyToString) {
VerifyCopyToString(absl::Cord()); // empty cords cannot carry CRCs
VerifyCopyToString(MaybeHardened(absl::Cord("small cord")));
VerifyCopyToString(MaybeHardened(
absl::MakeFragmentedCord({"fragmented ", "cord ", "to ", "test ",
"copying ", "to ", "a ", "string."})));
}
TEST_P(CordTest, TryFlatEmpty) {
absl::Cord c;
EXPECT_EQ(c.TryFlat(), "");
}
TEST_P(CordTest, TryFlatFlat) {
absl::Cord c("hello");
MaybeHarden(c);
EXPECT_EQ(c.TryFlat(), "hello");
}
TEST_P(CordTest, TryFlatSubstrInlined) {
absl::Cord c("hello");
c.RemovePrefix(1);
MaybeHarden(c);
EXPECT_EQ(c.TryFlat(), "ello");
}
TEST_P(CordTest, TryFlatSubstrFlat) {
absl::Cord c("longer than 15 bytes");
absl::Cord sub = absl::CordTestPeer::MakeSubstring(c, 1, c.size() - 1);
MaybeHarden(sub);
EXPECT_EQ(sub.TryFlat(), "onger than 15 bytes");
}
TEST_P(CordTest, TryFlatConcat) {
absl::Cord c = absl::MakeFragmentedCord({"hel", "lo"});
MaybeHarden(c);
EXPECT_EQ(c.TryFlat(), absl::nullopt);
}
TEST_P(CordTest, TryFlatExternal) {
absl::Cord c = absl::MakeCordFromExternal("hell", [](absl::string_view) {});
MaybeHarden(c);
EXPECT_EQ(c.TryFlat(), "hell");
}
TEST_P(CordTest, TryFlatSubstrExternal) {
absl::Cord c = absl::MakeCordFromExternal("hell", [](absl::string_view) {});
absl::Cord sub = absl::CordTestPeer::MakeSubstring(c, 1, c.size() - 1);
MaybeHarden(sub);
EXPECT_EQ(sub.TryFlat(), "ell");
}
TEST_P(CordTest, TryFlatCommonlyAssumedInvariants) {
// The behavior tested below is not part of the API contract of Cord, but it's
// something we intend to be true in our current implementation. This test
// exists to detect and prevent accidental breakage of the implementation.
absl::string_view fragments[] = {"A fragmented test",
" cord",
" to test subcords",
" of ",
"a",
" cord for",
" each chunk "
"returned by the ",
"iterator"};
absl::Cord c = absl::MakeFragmentedCord(fragments);
MaybeHarden(c);
int fragment = 0;
int offset = 0;
absl::Cord::CharIterator itc = c.char_begin();
for (absl::string_view sv : c.Chunks()) {
absl::string_view expected = fragments[fragment];
absl::Cord subcord1 = c.Subcord(offset, sv.length());
absl::Cord subcord2 = absl::Cord::AdvanceAndRead(&itc, sv.size());
EXPECT_EQ(subcord1.TryFlat(), expected);
EXPECT_EQ(subcord2.TryFlat(), expected);
++fragment;
offset += sv.length();
}
}
static bool IsFlat(const absl::Cord& c) {
return c.chunk_begin() == c.chunk_end() || ++c.chunk_begin() == c.chunk_end();
}
static void VerifyFlatten(absl::Cord c) {
std::string old_contents(c);
absl::string_view old_flat;
bool already_flat_and_non_empty = IsFlat(c) && !c.empty();
if (already_flat_and_non_empty) {
old_flat = *c.chunk_begin();
}
absl::string_view new_flat = c.Flatten();
// Verify that the contents of the flattened Cord are correct.
EXPECT_EQ(new_flat, old_contents);
EXPECT_EQ(std::string(c), old_contents);
// If the Cord contained data and was already flat, verify that the data
// wasn't copied.
if (already_flat_and_non_empty) {
EXPECT_EQ(old_flat.data(), new_flat.data())
<< "Allocated new memory even though the Cord was already flat.";
}
// Verify that the flattened Cord is in fact flat.
EXPECT_TRUE(IsFlat(c));
}
TEST_P(CordTest, Flatten) {
VerifyFlatten(absl::Cord());
VerifyFlatten(MaybeHardened(absl::Cord("small cord")));
VerifyFlatten(
MaybeHardened(absl::Cord("larger than small buffer optimization")));
VerifyFlatten(MaybeHardened(
absl::MakeFragmentedCord({"small ", "fragmented ", "cord"})));
// Test with a cord that is longer than the largest flat buffer
RandomEngine rng(GTEST_FLAG_GET(random_seed));
VerifyFlatten(MaybeHardened(absl::Cord(RandomLowercaseString(&rng, 8192))));
}
// Test data
namespace {
class TestData {
private:
std::vector<std::string> data_;
// Return a std::string of the specified length.
static std::string MakeString(int length) {
std::string result;
char buf[30];
snprintf(buf, sizeof(buf), "(%d)", length);
while (result.size() < length) {
result += buf;
}
result.resize(length);
return result;
}
public:
TestData() {
// short strings increasing in length by one
for (int i = 0; i < 30; i++) {
data_.push_back(MakeString(i));
}
// strings around half kMaxFlatLength
static const int kMaxFlatLength = 4096 - 9;
static const int kHalf = kMaxFlatLength / 2;
for (int i = -10; i <= +10; i++) {
data_.push_back(MakeString(kHalf + i));
}
for (int i = -10; i <= +10; i++) {
data_.push_back(MakeString(kMaxFlatLength + i));
}
}
size_t size() const { return data_.size(); }
const std::string& data(size_t i) const { return data_[i]; }
};
} // namespace
TEST_P(CordTest, MultipleLengths) {
TestData d;
for (size_t i = 0; i < d.size(); i++) {
std::string a = d.data(i);
{ // Construct from Cord
absl::Cord tmp(a);
absl::Cord x(tmp);
MaybeHarden(x);
EXPECT_EQ(a, std::string(x)) << "'" << a << "'";
}
{ // Construct from absl::string_view
absl::Cord x(a);
MaybeHarden(x);
EXPECT_EQ(a, std::string(x)) << "'" << a << "'";
}
{ // Append cord to self
absl::Cord self(a);
MaybeHarden(self);
self.Append(self);
EXPECT_EQ(a + a, std::string(self)) << "'" << a << "' + '" << a << "'";
}
{ // Prepend cord to self
absl::Cord self(a);
MaybeHarden(self);
self.Prepend(self);
EXPECT_EQ(a + a, std::string(self)) << "'" << a << "' + '" << a << "'";
}
// Try to append/prepend others
for (size_t j = 0; j < d.size(); j++) {
std::string b = d.data(j);
{ // CopyFrom Cord
absl::Cord x(a);
absl::Cord y(b);
MaybeHarden(x);
x = y;
EXPECT_EQ(b, std::string(x)) << "'" << a << "' + '" << b << "'";
}
{ // CopyFrom absl::string_view
absl::Cord x(a);
MaybeHarden(x);
x = b;
EXPECT_EQ(b, std::string(x)) << "'" << a << "' + '" << b << "'";
}
{ // Cord::Append(Cord)
absl::Cord x(a);
absl::Cord y(b);
MaybeHarden(x);
x.Append(y);
EXPECT_EQ(a + b, std::string(x)) << "'" << a << "' + '" << b << "'";
}
{ // Cord::Append(absl::string_view)
absl::Cord x(a);
MaybeHarden(x);
x.Append(b);
EXPECT_EQ(a + b, std::string(x)) << "'" << a << "' + '" << b << "'";
}
{ // Cord::Prepend(Cord)
absl::Cord x(a);
absl::Cord y(b);
MaybeHarden(x);
x.Prepend(y);
EXPECT_EQ(b + a, std::string(x)) << "'" << b << "' + '" << a << "'";
}
{ // Cord::Prepend(absl::string_view)
absl::Cord x(a);
MaybeHarden(x);
x.Prepend(b);
EXPECT_EQ(b + a, std::string(x)) << "'" << b << "' + '" << a << "'";
}
}
}
}
namespace {
TEST_P(CordTest, RemoveSuffixWithExternalOrSubstring) {
absl::Cord cord = absl::MakeCordFromExternal(
"foo bar baz", [](absl::string_view s) { DoNothing(s, nullptr); });
EXPECT_EQ("foo bar baz", std::string(cord));
MaybeHarden(cord);
// This RemoveSuffix() will wrap the EXTERNAL node in a SUBSTRING node.
cord.RemoveSuffix(4);
EXPECT_EQ("foo bar", std::string(cord));
MaybeHarden(cord);
// This RemoveSuffix() will adjust the SUBSTRING node in-place.
cord.RemoveSuffix(4);
EXPECT_EQ("foo", std::string(cord));
}
TEST_P(CordTest, RemoveSuffixMakesZeroLengthNode) {
absl::Cord c;
c.Append(absl::Cord(std::string(100, 'x')));
absl::Cord other_ref = c; // Prevent inplace appends
MaybeHarden(c);
c.Append(absl::Cord(std::string(200, 'y')));
c.RemoveSuffix(200);
EXPECT_EQ(std::string(100, 'x'), std::string(c));
}
} // namespace
// CordSpliceTest contributed by hendrie.
namespace {
// Create a cord with an external memory block filled with 'z'
absl::Cord CordWithZedBlock(size_t size) {
char* data = new char[size];
if (size > 0) {
memset(data, 'z', size);
}
absl::Cord cord = absl::MakeCordFromExternal(
absl::string_view(data, size),
[](absl::string_view s) { delete[] s.data(); });
return cord;
}
// Establish that ZedBlock does what we think it does.
TEST_P(CordTest, CordSpliceTestZedBlock) {
absl::Cord blob = CordWithZedBlock(10);
MaybeHarden(blob);
EXPECT_EQ(10, blob.size());
std::string s;
absl::CopyCordToString(blob, &s);
EXPECT_EQ("zzzzzzzzzz", s);
}
TEST_P(CordTest, CordSpliceTestZedBlock0) {
absl::Cord blob = CordWithZedBlock(0);
MaybeHarden(blob);
EXPECT_EQ(0, blob.size());
std::string s;
absl::CopyCordToString(blob, &s);
EXPECT_EQ("", s);
}
TEST_P(CordTest, CordSpliceTestZedBlockSuffix1) {
absl::Cord blob = CordWithZedBlock(10);
MaybeHarden(blob);
EXPECT_EQ(10, blob.size());
absl::Cord suffix(blob);
suffix.RemovePrefix(9);
EXPECT_EQ(1, suffix.size());
std::string s;
absl::CopyCordToString(suffix, &s);
EXPECT_EQ("z", s);
}
// Remove all of a prefix block
TEST_P(CordTest, CordSpliceTestZedBlockSuffix0) {
absl::Cord blob = CordWithZedBlock(10);
MaybeHarden(blob);
EXPECT_EQ(10, blob.size());
absl::Cord suffix(blob);
suffix.RemovePrefix(10);
EXPECT_EQ(0, suffix.size());
std::string s;
absl::CopyCordToString(suffix, &s);
EXPECT_EQ("", s);
}
absl::Cord BigCord(size_t len, char v) {
std::string s(len, v);
return absl::Cord(s);
}
// Splice block into cord.
absl::Cord SpliceCord(const absl::Cord& blob, int64_t offset,
const absl::Cord& block) {
ABSL_RAW_CHECK(offset >= 0, "");
ABSL_RAW_CHECK(offset + block.size() <= blob.size(), "");
absl::Cord result(blob);
result.RemoveSuffix(blob.size() - offset);
result.Append(block);
absl::Cord suffix(blob);
suffix.RemovePrefix(offset + block.size());
result.Append(suffix);
ABSL_RAW_CHECK(blob.size() == result.size(), "");
return result;
}
// Taking an empty suffix of a block breaks appending.
TEST_P(CordTest, CordSpliceTestRemoveEntireBlock1) {
absl::Cord zero = CordWithZedBlock(10);
MaybeHarden(zero);
absl::Cord suffix(zero);
suffix.RemovePrefix(10);
absl::Cord result;
result.Append(suffix);
}
TEST_P(CordTest, CordSpliceTestRemoveEntireBlock2) {
absl::Cord zero = CordWithZedBlock(10);
MaybeHarden(zero);
absl::Cord prefix(zero);
prefix.RemoveSuffix(10);
absl::Cord suffix(zero);
suffix.RemovePrefix(10);
absl::Cord result(prefix);
result.Append(suffix);
}
TEST_P(CordTest, CordSpliceTestRemoveEntireBlock3) {
absl::Cord blob = CordWithZedBlock(10);
absl::Cord block = BigCord(10, 'b');
MaybeHarden(blob);
MaybeHarden(block);
blob = SpliceCord(blob, 0, block);
}
struct CordCompareTestCase {
template <typename LHS, typename RHS>
CordCompareTestCase(const LHS& lhs, const RHS& rhs, bool use_crc)
: lhs_cord(lhs), rhs_cord(rhs) {
if (use_crc) {
lhs_cord.SetExpectedChecksum(1);
}
}
absl::Cord lhs_cord;
absl::Cord rhs_cord;
};
const auto sign = [](int x) { return x == 0 ? 0 : (x > 0 ? 1 : -1); };
void VerifyComparison(const CordCompareTestCase& test_case) {
std::string lhs_string(test_case.lhs_cord);
std::string rhs_string(test_case.rhs_cord);
int expected = sign(lhs_string.compare(rhs_string));
EXPECT_EQ(expected, test_case.lhs_cord.Compare(test_case.rhs_cord))
<< "LHS=" << lhs_string << "; RHS=" << rhs_string;
EXPECT_EQ(expected, test_case.lhs_cord.Compare(rhs_string))
<< "LHS=" << lhs_string << "; RHS=" << rhs_string;
EXPECT_EQ(-expected, test_case.rhs_cord.Compare(test_case.lhs_cord))
<< "LHS=" << rhs_string << "; RHS=" << lhs_string;
EXPECT_EQ(-expected, test_case.rhs_cord.Compare(lhs_string))
<< "LHS=" << rhs_string << "; RHS=" << lhs_string;
}
TEST_P(CordTest, Compare) {
absl::Cord subcord("aaaaaBBBBBcccccDDDDD");
subcord = subcord.Subcord(3, 10);
absl::Cord tmp("aaaaaaaaaaaaaaaa");
tmp.Append("BBBBBBBBBBBBBBBB");
absl::Cord concat = absl::Cord("cccccccccccccccc");
concat.Append("DDDDDDDDDDDDDDDD");
concat.Prepend(tmp);
absl::Cord concat2("aaaaaaaaaaaaa");
concat2.Append("aaaBBBBBBBBBBBBBBBBccccc");
concat2.Append("cccccccccccDDDDDDDDDDDDDD");
concat2.Append("DD");
const bool use_crc = UseCrc();
std::vector<CordCompareTestCase> test_cases = {{
// Inline cords
{"abcdef", "abcdef", use_crc},
{"abcdef", "abcdee", use_crc},
{"abcdef", "abcdeg", use_crc},
{"bbcdef", "abcdef", use_crc},
{"bbcdef", "abcdeg", use_crc},
{"abcdefa", "abcdef", use_crc},
{"abcdef", "abcdefa", use_crc},
// Small flat cords
{"aaaaaBBBBBcccccDDDDD", "aaaaaBBBBBcccccDDDDD", use_crc},
{"aaaaaBBBBBcccccDDDDD", "aaaaaBBBBBxccccDDDDD", use_crc},
{"aaaaaBBBBBcxcccDDDDD", "aaaaaBBBBBcccccDDDDD", use_crc},
{"aaaaaBBBBBxccccDDDDD", "aaaaaBBBBBcccccDDDDX", use_crc},
{"aaaaaBBBBBcccccDDDDDa", "aaaaaBBBBBcccccDDDDD", use_crc},
{"aaaaaBBBBBcccccDDDDD", "aaaaaBBBBBcccccDDDDDa", use_crc},
// Subcords
{subcord, subcord, use_crc},
{subcord, "aaBBBBBccc", use_crc},
{subcord, "aaBBBBBccd", use_crc},
{subcord, "aaBBBBBccb", use_crc},
{subcord, "aaBBBBBxcb", use_crc},
{subcord, "aaBBBBBccca", use_crc},
{subcord, "aaBBBBBcc", use_crc},
// Concats
{concat, concat, use_crc},
{concat,
"aaaaaaaaaaaaaaaaBBBBBBBBBBBBBBBBccccccccccccccccDDDDDDDDDDDDDDDD",
use_crc},
{concat,
"aaaaaaaaaaaaaaaaBBBBBBBBBBBBBBBBcccccccccccccccxDDDDDDDDDDDDDDDD",
use_crc},
{concat,
"aaaaaaaaaaaaaaaaBBBBBBBBBBBBBBBBacccccccccccccccDDDDDDDDDDDDDDDD",
use_crc},
{concat,
"aaaaaaaaaaaaaaaaBBBBBBBBBBBBBBBBccccccccccccccccDDDDDDDDDDDDDDD",
use_crc},
{concat,
"aaaaaaaaaaaaaaaaBBBBBBBBBBBBBBBBccccccccccccccccDDDDDDDDDDDDDDDDe",
use_crc},
{concat, concat2, use_crc},
}};
for (const auto& tc : test_cases) {
VerifyComparison(tc);
}
}
TEST_P(CordTest, CompareAfterAssign) {
absl::Cord a("aaaaaa1111111");
absl::Cord b("aaaaaa2222222");
MaybeHarden(a);
a = "cccccc";
b = "cccccc";
EXPECT_EQ(a, b);
EXPECT_FALSE(a < b);
a = "aaaa";
b = "bbbbb";
a = "";
b = "";
EXPECT_EQ(a, b);
EXPECT_FALSE(a < b);
}
// Test CompareTo() and ComparePrefix() against string and substring
// comparison methods from basic_string.
static void TestCompare(const absl::Cord& c, const absl::Cord& d,
RandomEngine* rng) {
typedef std::basic_string<uint8_t> ustring;
ustring cs(reinterpret_cast<const uint8_t*>(std::string(c).data()), c.size());
ustring ds(reinterpret_cast<const uint8_t*>(std::string(d).data()), d.size());
// ustring comparison is ideal because we expect Cord comparisons to be
// based on unsigned byte comparisons regardless of whether char is signed.
int expected = sign(cs.compare(ds));
EXPECT_EQ(expected, sign(c.Compare(d))) << c << ", " << d;
}
TEST_P(CordTest, CompareComparisonIsUnsigned) {
RandomEngine rng(GTEST_FLAG_GET(random_seed));
std::uniform_int_distribution<uint32_t> uniform_uint8(0, 255);
char x = static_cast<char>(uniform_uint8(rng));
TestCompare(
absl::Cord(std::string(GetUniformRandomUpTo(&rng, 100), x)),
absl::Cord(std::string(GetUniformRandomUpTo(&rng, 100), x ^ 0x80)), &rng);
}
TEST_P(CordTest, CompareRandomComparisons) {
const int kIters = 5000;
RandomEngine rng(GTEST_FLAG_GET(random_seed));
int n = GetUniformRandomUpTo(&rng, 5000);
absl::Cord a[] = {MakeExternalCord(n),
absl::Cord("ant"),
absl::Cord("elephant"),
absl::Cord("giraffe"),
absl::Cord(std::string(GetUniformRandomUpTo(&rng, 100),
GetUniformRandomUpTo(&rng, 100))),
absl::Cord(""),
absl::Cord("x"),
absl::Cord("A"),
absl::Cord("B"),
absl::Cord("C")};
for (int i = 0; i < kIters; i++) {
absl::Cord c, d;
for (int j = 0; j < (i % 7) + 1; j++) {
c.Append(a[GetUniformRandomUpTo(&rng, ABSL_ARRAYSIZE(a))]);
d.Append(a[GetUniformRandomUpTo(&rng, ABSL_ARRAYSIZE(a))]);
}
std::bernoulli_distribution coin_flip(0.5);
MaybeHarden(c);
MaybeHarden(d);
TestCompare(coin_flip(rng) ? c : absl::Cord(std::string(c)),
coin_flip(rng) ? d : absl::Cord(std::string(d)), &rng);
}
}
template <typename T1, typename T2>
void CompareOperators() {
const T1 a("a");
const T2 b("b");
EXPECT_TRUE(a == a);
// For pointer type (i.e. `const char*`), operator== compares the address
// instead of the string, so `a == const char*("a")` isn't necessarily true.
EXPECT_TRUE(std::is_pointer<T1>::value || a == T1("a"));
EXPECT_TRUE(std::is_pointer<T2>::value || a == T2("a"));
EXPECT_FALSE(a == b);
EXPECT_TRUE(a != b);
EXPECT_FALSE(a != a);
EXPECT_TRUE(a < b);
EXPECT_FALSE(b < a);
EXPECT_TRUE(b > a);
EXPECT_FALSE(a > b);
EXPECT_TRUE(a >= a);
EXPECT_TRUE(b >= a);
EXPECT_FALSE(a >= b);
EXPECT_TRUE(a <= a);
EXPECT_TRUE(a <= b);
EXPECT_FALSE(b <= a);
}
TEST_P(CordTest, ComparisonOperators_Cord_Cord) {
CompareOperators<absl::Cord, absl::Cord>();
}
TEST_P(CordTest, ComparisonOperators_Cord_StringPiece) {
CompareOperators<absl::Cord, absl::string_view>();
}
TEST_P(CordTest, ComparisonOperators_StringPiece_Cord) {
CompareOperators<absl::string_view, absl::Cord>();
}
TEST_P(CordTest, ComparisonOperators_Cord_string) {
CompareOperators<absl::Cord, std::string>();
}
TEST_P(CordTest, ComparisonOperators_string_Cord) {
CompareOperators<std::string, absl::Cord>();
}
TEST_P(CordTest, ComparisonOperators_stdstring_Cord) {
CompareOperators<std::string, absl::Cord>();
}
TEST_P(CordTest, ComparisonOperators_Cord_stdstring) {
CompareOperators<absl::Cord, std::string>();
}
TEST_P(CordTest, ComparisonOperators_charstar_Cord) {
CompareOperators<const char*, absl::Cord>();
}
TEST_P(CordTest, ComparisonOperators_Cord_charstar) {
CompareOperators<absl::Cord, const char*>();
}
TEST_P(CordTest, ConstructFromExternalReleaserInvoked) {
// Empty external memory means the releaser should be called immediately.
{
bool invoked = false;
auto releaser = [&invoked](absl::string_view) { invoked = true; };
{
auto c = absl::MakeCordFromExternal("", releaser);
EXPECT_TRUE(invoked);
}
}
// If the size of the data is small enough, a future constructor
// implementation may copy the bytes and immediately invoke the releaser
// instead of creating an external node. We make a large dummy std::string to
// make this test independent of such an optimization.
std::string large_dummy(2048, 'c');
{
bool invoked = false;
auto releaser = [&invoked](absl::string_view) { invoked = true; };
{
auto c = absl::MakeCordFromExternal(large_dummy, releaser);
EXPECT_FALSE(invoked);
}
EXPECT_TRUE(invoked);
}
{
bool invoked = false;
auto releaser = [&invoked](absl::string_view) { invoked = true; };
{
absl::Cord copy;
{
auto c = absl::MakeCordFromExternal(large_dummy, releaser);
copy = c;
EXPECT_FALSE(invoked);
}
EXPECT_FALSE(invoked);
}
EXPECT_TRUE(invoked);
}
}
TEST_P(CordTest, ConstructFromExternalCompareContents) {
RandomEngine rng(GTEST_FLAG_GET(random_seed));
for (int length = 1; length <= 2048; length *= 2) {
std::string data = RandomLowercaseString(&rng, length);
auto* external = new std::string(data);
auto cord =
absl::MakeCordFromExternal(*external, [external](absl::string_view sv) {
EXPECT_EQ(external->data(), sv.data());
EXPECT_EQ(external->size(), sv.size());
delete external;
});
MaybeHarden(cord);
EXPECT_EQ(data, cord);
}
}
TEST_P(CordTest, ConstructFromExternalLargeReleaser) {
RandomEngine rng(GTEST_FLAG_GET(random_seed));
constexpr size_t kLength = 256;
std::string data = RandomLowercaseString(&rng, kLength);
std::array<char, kLength> data_array;
for (size_t i = 0; i < kLength; ++i) data_array[i] = data[i];
bool invoked = false;
auto releaser = [data_array, &invoked](absl::string_view data) {
EXPECT_EQ(data, absl::string_view(data_array.data(), data_array.size()));
invoked = true;
};
(void)MaybeHardened(absl::MakeCordFromExternal(data, releaser));
EXPECT_TRUE(invoked);
}
TEST_P(CordTest, ConstructFromExternalFunctionPointerReleaser) {
static absl::string_view data("hello world");
static bool invoked;
auto* releaser =
static_cast<void (*)(absl::string_view)>([](absl::string_view sv) {
EXPECT_EQ(data, sv);
invoked = true;
});
invoked = false;
(void)MaybeHardened(absl::MakeCordFromExternal(data, releaser));
EXPECT_TRUE(invoked);
invoked = false;
(void)MaybeHardened(absl::MakeCordFromExternal(data, *releaser));
EXPECT_TRUE(invoked);
}
TEST_P(CordTest, ConstructFromExternalMoveOnlyReleaser) {
struct Releaser {
explicit Releaser(bool* invoked) : invoked(invoked) {}
Releaser(Releaser&& other) noexcept : invoked(other.invoked) {}
void operator()(absl::string_view) const { *invoked = true; }
bool* invoked;
};
bool invoked = false;
(void)MaybeHardened(absl::MakeCordFromExternal("dummy", Releaser(&invoked)));
EXPECT_TRUE(invoked);
}
TEST_P(CordTest, ConstructFromExternalNoArgLambda) {
bool invoked = false;
(void)MaybeHardened(
absl::MakeCordFromExternal("dummy", [&invoked]() { invoked = true; }));
EXPECT_TRUE(invoked);
}
TEST_P(CordTest, ConstructFromExternalStringViewArgLambda) {
bool invoked = false;
(void)MaybeHardened(absl::MakeCordFromExternal(
"dummy", [&invoked](absl::string_view) { invoked = true; }));
EXPECT_TRUE(invoked);
}
TEST_P(CordTest, ConstructFromExternalNonTrivialReleaserDestructor) {
struct Releaser {
explicit Releaser(bool* destroyed) : destroyed(destroyed) {}
~Releaser() { *destroyed = true; }
void operator()(absl::string_view) const {}
bool* destroyed;
};
bool destroyed = false;
Releaser releaser(&destroyed);
(void)MaybeHardened(absl::MakeCordFromExternal("dummy", releaser));
EXPECT_TRUE(destroyed);
}
TEST_P(CordTest, ConstructFromExternalReferenceQualifierOverloads) {
enum InvokedAs { kMissing, kLValue, kRValue };
enum CopiedAs { kNone, kMove, kCopy };
struct Tracker {
CopiedAs copied_as = kNone;
InvokedAs invoked_as = kMissing;
void Record(InvokedAs rhs) {
ASSERT_EQ(invoked_as, kMissing);
invoked_as = rhs;
}
void Record(CopiedAs rhs) {
if (copied_as == kNone || rhs == kCopy) copied_as = rhs;
}
} tracker;
class Releaser {
public:
explicit Releaser(Tracker* tracker) : tr_(tracker) { *tracker = Tracker(); }
Releaser(Releaser&& rhs) : tr_(rhs.tr_) { tr_->Record(kMove); }
Releaser(const Releaser& rhs) : tr_(rhs.tr_) { tr_->Record(kCopy); }
void operator()(absl::string_view) & { tr_->Record(kLValue); }
void operator()(absl::string_view) && { tr_->Record(kRValue); }
private:
Tracker* tr_;
};
const Releaser releaser1(&tracker);
(void)MaybeHardened(absl::MakeCordFromExternal("", releaser1));
EXPECT_EQ(tracker.copied_as, kCopy);
EXPECT_EQ(tracker.invoked_as, kRValue);
const Releaser releaser2(&tracker);
(void)MaybeHardened(absl::MakeCordFromExternal("", releaser2));
EXPECT_EQ(tracker.copied_as, kCopy);
EXPECT_EQ(tracker.invoked_as, kRValue);
Releaser releaser3(&tracker);
(void)MaybeHardened(absl::MakeCordFromExternal("", std::move(releaser3)));
EXPECT_EQ(tracker.copied_as, kMove);
EXPECT_EQ(tracker.invoked_as, kRValue);
Releaser releaser4(&tracker);
(void)MaybeHardened(absl::MakeCordFromExternal("dummy", releaser4));
EXPECT_EQ(tracker.copied_as, kCopy);
EXPECT_EQ(tracker.invoked_as, kRValue);
const Releaser releaser5(&tracker);
(void)MaybeHardened(absl::MakeCordFromExternal("dummy", releaser5));
EXPECT_EQ(tracker.copied_as, kCopy);
EXPECT_EQ(tracker.invoked_as, kRValue);
Releaser releaser6(&tracker);
(void)MaybeHardened(absl::MakeCordFromExternal("foo", std::move(releaser6)));
EXPECT_EQ(tracker.copied_as, kMove);
EXPECT_EQ(tracker.invoked_as, kRValue);
}
TEST_P(CordTest, ExternalMemoryBasicUsage) {
static const char* strings[] = {"", "hello", "there"};
for (const char* str : strings) {
absl::Cord dst("(prefix)");
MaybeHarden(dst);
AddExternalMemory(str, &dst);
MaybeHarden(dst);
dst.Append("(suffix)");
EXPECT_EQ((std::string("(prefix)") + str + std::string("(suffix)")),
std::string(dst));
}
}
TEST_P(CordTest, ExternalMemoryRemovePrefixSuffix) {
// Exhaustively try all sub-strings.
absl::Cord cord = MakeComposite();
std::string s = std::string(cord);
for (int offset = 0; offset <= s.size(); offset++) {
for (int length = 0; length <= s.size() - offset; length++) {
absl::Cord result(cord);
MaybeHarden(result);
result.RemovePrefix(offset);
MaybeHarden(result);
result.RemoveSuffix(result.size() - length);
EXPECT_EQ(s.substr(offset, length), std::string(result))
<< offset << " " << length;
}
}
}
TEST_P(CordTest, ExternalMemoryGet) {
absl::Cord cord("hello");
AddExternalMemory(" world!", &cord);
MaybeHarden(cord);
AddExternalMemory(" how are ", &cord);
cord.Append(" you?");
MaybeHarden(cord);
std::string s = std::string(cord);
for (int i = 0; i < s.size(); i++) {
EXPECT_EQ(s[i], cord[i]);
}
}
// CordMemoryUsage tests verify the correctness of the EstimatedMemoryUsage()
// We use whiteboxed expectations based on our knowledge of the layout and size
// of empty and inlined cords, and flat nodes.
constexpr auto kFairShare = absl::CordMemoryAccounting::kFairShare;
// Creates a cord of `n` `c` values, making sure no string stealing occurs.
absl::Cord MakeCord(size_t n, char c) {
const std::string s(n, c);
return absl::Cord(s);
}
TEST(CordTest, CordMemoryUsageEmpty) {
absl::Cord cord;
EXPECT_EQ(sizeof(absl::Cord), cord.EstimatedMemoryUsage());
EXPECT_EQ(sizeof(absl::Cord), cord.EstimatedMemoryUsage(kFairShare));
}
TEST(CordTest, CordMemoryUsageInlined) {
absl::Cord a("hello");
EXPECT_EQ(a.EstimatedMemoryUsage(), sizeof(absl::Cord));
EXPECT_EQ(a.EstimatedMemoryUsage(kFairShare), sizeof(absl::Cord));
}
TEST(CordTest, CordMemoryUsageExternalMemory) {
absl::Cord cord;
AddExternalMemory(std::string(1000, 'x'), &cord);
const size_t expected =
sizeof(absl::Cord) + 1000 + sizeof(CordRepExternal) + sizeof(intptr_t);
EXPECT_EQ(cord.EstimatedMemoryUsage(), expected);
EXPECT_EQ(cord.EstimatedMemoryUsage(kFairShare), expected);
}
TEST(CordTest, CordMemoryUsageFlat) {
absl::Cord cord = MakeCord(1000, 'a');
const size_t flat_size =
absl::CordTestPeer::Tree(cord)->flat()->AllocatedSize();
EXPECT_EQ(cord.EstimatedMemoryUsage(), sizeof(absl::Cord) + flat_size);
EXPECT_EQ(cord.EstimatedMemoryUsage(kFairShare),
sizeof(absl::Cord) + flat_size);
}
TEST(CordTest, CordMemoryUsageSubStringSharedFlat) {
absl::Cord flat = MakeCord(2000, 'a');
const size_t flat_size =
absl::CordTestPeer::Tree(flat)->flat()->AllocatedSize();
absl::Cord cord = flat.Subcord(500, 1000);
EXPECT_EQ(cord.EstimatedMemoryUsage(),
sizeof(absl::Cord) + sizeof(CordRepSubstring) + flat_size);
EXPECT_EQ(cord.EstimatedMemoryUsage(kFairShare),
sizeof(absl::Cord) + sizeof(CordRepSubstring) + flat_size / 2);
}
TEST(CordTest, CordMemoryUsageFlatShared) {
absl::Cord shared = MakeCord(1000, 'a');
absl::Cord cord(shared);
const size_t flat_size =
absl::CordTestPeer::Tree(cord)->flat()->AllocatedSize();
EXPECT_EQ(cord.EstimatedMemoryUsage(), sizeof(absl::Cord) + flat_size);
EXPECT_EQ(cord.EstimatedMemoryUsage(kFairShare),
sizeof(absl::Cord) + flat_size / 2);
}
TEST(CordTest, CordMemoryUsageFlatHardenedAndShared) {
absl::Cord shared = MakeCord(1000, 'a');
absl::Cord cord(shared);
const size_t flat_size =
absl::CordTestPeer::Tree(cord)->flat()->AllocatedSize();
cord.SetExpectedChecksum(1);
EXPECT_EQ(cord.EstimatedMemoryUsage(),
sizeof(absl::Cord) + sizeof(CordRepCrc) + flat_size);
EXPECT_EQ(cord.EstimatedMemoryUsage(kFairShare),
sizeof(absl::Cord) + sizeof(CordRepCrc) + flat_size / 2);
absl::Cord cord2(cord);
EXPECT_EQ(cord2.EstimatedMemoryUsage(),
sizeof(absl::Cord) + sizeof(CordRepCrc) + flat_size);
EXPECT_EQ(cord2.EstimatedMemoryUsage(kFairShare),
sizeof(absl::Cord) + (sizeof(CordRepCrc) + flat_size / 2) / 2);
}
TEST(CordTest, CordMemoryUsageBTree) {
absl::Cord cord1;
size_t flats1_size = 0;
absl::Cord flats1[4] = {MakeCord(1000, 'a'), MakeCord(1100, 'a'),
MakeCord(1200, 'a'), MakeCord(1300, 'a')};
for (absl::Cord flat : flats1) {
flats1_size += absl::CordTestPeer::Tree(flat)->flat()->AllocatedSize();
cord1.Append(std::move(flat));
}
// Make sure the created cord is a BTREE tree. Under some builds such as
// windows DLL, we may have ODR like effects on the flag, meaning the DLL
// code will run with the picked up default.
if (!absl::CordTestPeer::Tree(cord1)->IsBtree()) {
ABSL_RAW_LOG(WARNING, "Cord library code not respecting btree flag");
return;
}
size_t rep1_size = sizeof(CordRepBtree) + flats1_size;
size_t rep1_shared_size = sizeof(CordRepBtree) + flats1_size / 2;
EXPECT_EQ(cord1.EstimatedMemoryUsage(), sizeof(absl::Cord) + rep1_size);
EXPECT_EQ(cord1.EstimatedMemoryUsage(kFairShare),
sizeof(absl::Cord) + rep1_shared_size);
absl::Cord cord2;
size_t flats2_size = 0;
absl::Cord flats2[4] = {MakeCord(600, 'a'), MakeCord(700, 'a'),
MakeCord(800, 'a'), MakeCord(900, 'a')};
for (absl::Cord& flat : flats2) {
flats2_size += absl::CordTestPeer::Tree(flat)->flat()->AllocatedSize();
cord2.Append(std::move(flat));
}
size_t rep2_size = sizeof(CordRepBtree) + flats2_size;
EXPECT_EQ(cord2.EstimatedMemoryUsage(), sizeof(absl::Cord) + rep2_size);
EXPECT_EQ(cord2.EstimatedMemoryUsage(kFairShare),
sizeof(absl::Cord) + rep2_size);
absl::Cord cord(cord1);
cord.Append(std::move(cord2));
EXPECT_EQ(cord.EstimatedMemoryUsage(),
sizeof(absl::Cord) + sizeof(CordRepBtree) + rep1_size + rep2_size);
EXPECT_EQ(cord.EstimatedMemoryUsage(kFairShare),
sizeof(absl::Cord) + sizeof(CordRepBtree) + rep1_shared_size / 2 +
rep2_size);
}
// Regtest for a change that had to be rolled back because it expanded out
// of the InlineRep too soon, which was observable through MemoryUsage().
TEST_P(CordTest, CordMemoryUsageInlineRep) {
constexpr size_t kMaxInline = 15; // Cord::InlineRep::N
const std::string small_string(kMaxInline, 'x');
absl::Cord c1(small_string);
absl::Cord c2;
c2.Append(small_string);
EXPECT_EQ(c1, c2);
EXPECT_EQ(c1.EstimatedMemoryUsage(), c2.EstimatedMemoryUsage());
}
} // namespace
// Regtest for 7510292 (fix a bug introduced by 7465150)
TEST_P(CordTest, Concat_Append) {
// Create a rep of type CONCAT
absl::Cord s1("foobarbarbarbarbar");
MaybeHarden(s1);
s1.Append("abcdefgabcdefgabcdefgabcdefgabcdefgabcdefgabcdefg");
size_t size = s1.size();
// Create a copy of s1 and append to it.
absl::Cord s2 = s1;
MaybeHarden(s2);
s2.Append("x");
// 7465150 modifies s1 when it shouldn't.
EXPECT_EQ(s1.size(), size);
EXPECT_EQ(s2.size(), size + 1);
}
TEST_P(CordTest, DiabolicalGrowth) {
// This test exercises a diabolical Append(<one char>) on a cord, making the
// cord shared before each Append call resulting in a terribly fragmented
// resulting cord.
// TODO(b/183983616): Apply some minimum compaction when copying a shared
// source cord into a mutable copy for updates in CordRepRing.
RandomEngine rng(GTEST_FLAG_GET(random_seed));
const std::string expected = RandomLowercaseString(&rng, 5000);
absl::Cord cord;
for (char c : expected) {
absl::Cord shared(cord);
cord.Append(absl::string_view(&c, 1));
MaybeHarden(cord);
}
std::string value;
absl::CopyCordToString(cord, &value);
EXPECT_EQ(value, expected);
ABSL_RAW_LOG(INFO, "Diabolical size allocated = %zu",
cord.EstimatedMemoryUsage());
}
// The following tests check support for >4GB cords in 64-bit binaries, and
// 2GB-4GB cords in 32-bit binaries. This function returns the large cord size
// that's appropriate for the binary.
// Construct a huge cord with the specified valid prefix.
static absl::Cord MakeHuge(absl::string_view prefix) {
absl::Cord cord;
if (sizeof(size_t) > 4) {
// In 64-bit binaries, test 64-bit Cord support.
const size_t size =
static_cast<size_t>(std::numeric_limits<uint32_t>::max()) + 314;
cord.Append(absl::MakeCordFromExternal(
absl::string_view(prefix.data(), size),
[](absl::string_view s) { DoNothing(s, nullptr); }));
} else {
// Cords are limited to 32-bit lengths in 32-bit binaries. The following
// tests check for use of "signed int" to represent Cord length/offset.
// However absl::string_view does not allow lengths >= (1u<<31), so we need
// to append in two parts;
const size_t s1 = (1u << 31) - 1;
// For shorter cord, `Append` copies the data rather than allocating a new
// node. The threshold is currently set to 511, so `s2` needs to be bigger
// to not trigger the copy.
const size_t s2 = 600;
cord.Append(absl::MakeCordFromExternal(
absl::string_view(prefix.data(), s1),
[](absl::string_view s) { DoNothing(s, nullptr); }));
cord.Append(absl::MakeCordFromExternal(
absl::string_view("", s2),
[](absl::string_view s) { DoNothing(s, nullptr); }));
}
return cord;
}
TEST_P(CordTest, HugeCord) {
absl::Cord cord = MakeHuge("huge cord");
MaybeHarden(cord);
const size_t acceptable_delta =
100 + (UseCrc() ? sizeof(absl::cord_internal::CordRepCrc) : 0);
EXPECT_LE(cord.size(), cord.EstimatedMemoryUsage());
EXPECT_GE(cord.size() + acceptable_delta, cord.EstimatedMemoryUsage());
}
// Tests that Append() works ok when handed a self reference
TEST_P(CordTest, AppendSelf) {
// We run the test until data is ~16K
// This guarantees it covers small, medium and large data.
std::string control_data = "Abc";
absl::Cord data(control_data);
while (control_data.length() < 0x4000) {
MaybeHarden(data);
data.Append(data);
control_data.append(control_data);
ASSERT_EQ(control_data, data);
}
}
TEST_P(CordTest, MakeFragmentedCordFromInitializerList) {
absl::Cord fragmented =
absl::MakeFragmentedCord({"A ", "fragmented ", "Cord"});
MaybeHarden(fragmented);
EXPECT_EQ("A fragmented Cord", fragmented);
auto chunk_it = fragmented.chunk_begin();
ASSERT_TRUE(chunk_it != fragmented.chunk_end());
EXPECT_EQ("A ", *chunk_it);
ASSERT_TRUE(++chunk_it != fragmented.chunk_end());
EXPECT_EQ("fragmented ", *chunk_it);
ASSERT_TRUE(++chunk_it != fragmented.chunk_end());
EXPECT_EQ("Cord", *chunk_it);
ASSERT_TRUE(++chunk_it == fragmented.chunk_end());
}
TEST_P(CordTest, MakeFragmentedCordFromVector) {
std::vector<absl::string_view> chunks = {"A ", "fragmented ", "Cord"};
absl::Cord fragmented = absl::MakeFragmentedCord(chunks);
MaybeHarden(fragmented);
EXPECT_EQ("A fragmented Cord", fragmented);
auto chunk_it = fragmented.chunk_begin();
ASSERT_TRUE(chunk_it != fragmented.chunk_end());
EXPECT_EQ("A ", *chunk_it);
ASSERT_TRUE(++chunk_it != fragmented.chunk_end());
EXPECT_EQ("fragmented ", *chunk_it);
ASSERT_TRUE(++chunk_it != fragmented.chunk_end());
EXPECT_EQ("Cord", *chunk_it);
ASSERT_TRUE(++chunk_it == fragmented.chunk_end());
}
TEST_P(CordTest, CordChunkIteratorTraits) {
static_assert(std::is_copy_constructible<absl::Cord::ChunkIterator>::value,
"");
static_assert(std::is_copy_assignable<absl::Cord::ChunkIterator>::value, "");
// Move semantics to satisfy swappable via std::swap
static_assert(std::is_move_constructible<absl::Cord::ChunkIterator>::value,
"");
static_assert(std::is_move_assignable<absl::Cord::ChunkIterator>::value, "");
static_assert(
std::is_same<
std::iterator_traits<absl::Cord::ChunkIterator>::iterator_category,
std::input_iterator_tag>::value,
"");
static_assert(
std::is_same<std::iterator_traits<absl::Cord::ChunkIterator>::value_type,
absl::string_view>::value,
"");
static_assert(
std::is_same<
std::iterator_traits<absl::Cord::ChunkIterator>::difference_type,
ptrdiff_t>::value,
"");
static_assert(
std::is_same<std::iterator_traits<absl::Cord::ChunkIterator>::pointer,
const absl::string_view*>::value,
"");
static_assert(
std::is_same<std::iterator_traits<absl::Cord::ChunkIterator>::reference,
absl::string_view>::value,
"");
}
static void VerifyChunkIterator(const absl::Cord& cord,
size_t expected_chunks) {
EXPECT_EQ(cord.chunk_begin() == cord.chunk_end(), cord.empty()) << cord;
EXPECT_EQ(cord.chunk_begin() != cord.chunk_end(), !cord.empty());
absl::Cord::ChunkRange range = cord.Chunks();
EXPECT_EQ(range.begin() == range.end(), cord.empty());
EXPECT_EQ(range.begin() != range.end(), !cord.empty());
std::string content(cord);
size_t pos = 0;
auto pre_iter = cord.chunk_begin(), post_iter = cord.chunk_begin();
size_t n_chunks = 0;
while (pre_iter != cord.chunk_end() && post_iter != cord.chunk_end()) {
EXPECT_FALSE(pre_iter == cord.chunk_end()); // NOLINT: explicitly test ==
EXPECT_FALSE(post_iter == cord.chunk_end()); // NOLINT
EXPECT_EQ(pre_iter, post_iter);
EXPECT_EQ(*pre_iter, *post_iter);
EXPECT_EQ(pre_iter->data(), (*pre_iter).data());
EXPECT_EQ(pre_iter->size(), (*pre_iter).size());
absl::string_view chunk = *pre_iter;
EXPECT_FALSE(chunk.empty());
EXPECT_LE(pos + chunk.size(), content.size());
EXPECT_EQ(absl::string_view(content.c_str() + pos, chunk.size()), chunk);
int n_equal_iterators = 0;
for (absl::Cord::ChunkIterator it = range.begin(); it != range.end();
++it) {
n_equal_iterators += static_cast<int>(it == pre_iter);
}
EXPECT_EQ(n_equal_iterators, 1);
++pre_iter;
EXPECT_EQ(*post_iter++, chunk);
pos += chunk.size();
++n_chunks;
}
EXPECT_EQ(expected_chunks, n_chunks);
EXPECT_EQ(pos, content.size());
EXPECT_TRUE(pre_iter == cord.chunk_end()); // NOLINT: explicitly test ==
EXPECT_TRUE(post_iter == cord.chunk_end()); // NOLINT
}
TEST_P(CordTest, CordChunkIteratorOperations) {
absl::Cord empty_cord;
VerifyChunkIterator(empty_cord, 0);
absl::Cord small_buffer_cord("small cord");
MaybeHarden(small_buffer_cord);
VerifyChunkIterator(small_buffer_cord, 1);
absl::Cord flat_node_cord("larger than small buffer optimization");
MaybeHarden(flat_node_cord);
VerifyChunkIterator(flat_node_cord, 1);
VerifyChunkIterator(MaybeHardened(absl::MakeFragmentedCord(
{"a ", "small ", "fragmented ", "cord ", "for ",
"testing ", "chunk ", "iterations."})),
8);
absl::Cord reused_nodes_cord(std::string(40, 'c'));
reused_nodes_cord.Prepend(absl::Cord(std::string(40, 'b')));
MaybeHarden(reused_nodes_cord);
reused_nodes_cord.Prepend(absl::Cord(std::string(40, 'a')));
size_t expected_chunks = 3;
for (int i = 0; i < 8; ++i) {
reused_nodes_cord.Prepend(reused_nodes_cord);
MaybeHarden(reused_nodes_cord);
expected_chunks *= 2;
VerifyChunkIterator(reused_nodes_cord, expected_chunks);
}
RandomEngine rng(GTEST_FLAG_GET(random_seed));
absl::Cord flat_cord(RandomLowercaseString(&rng, 256));
absl::Cord subcords;
for (int i = 0; i < 128; ++i) subcords.Prepend(flat_cord.Subcord(i, 128));
VerifyChunkIterator(subcords, 128);
}
TEST_P(CordTest, AdvanceAndReadOnDataEdge) {
RandomEngine rng(GTEST_FLAG_GET(random_seed));
const std::string data = RandomLowercaseString(&rng, 2000);
for (bool as_flat : {true, false}) {
SCOPED_TRACE(as_flat ? "Flat" : "External");
absl::Cord cord =
as_flat ? absl::Cord(data)
: absl::MakeCordFromExternal(data, [](absl::string_view) {});
auto it = cord.Chars().begin();
#if !defined(NDEBUG) || ABSL_OPTION_HARDENED
EXPECT_DEATH_IF_SUPPORTED(cord.AdvanceAndRead(&it, 2001), ".*");
#endif
it = cord.Chars().begin();
absl::Cord frag = cord.AdvanceAndRead(&it, 2000);
EXPECT_EQ(frag, data);
EXPECT_TRUE(it == cord.Chars().end());
it = cord.Chars().begin();
frag = cord.AdvanceAndRead(&it, 200);
EXPECT_EQ(frag, data.substr(0, 200));
EXPECT_FALSE(it == cord.Chars().end());
frag = cord.AdvanceAndRead(&it, 1500);
EXPECT_EQ(frag, data.substr(200, 1500));
EXPECT_FALSE(it == cord.Chars().end());
frag = cord.AdvanceAndRead(&it, 300);
EXPECT_EQ(frag, data.substr(1700, 300));
EXPECT_TRUE(it == cord.Chars().end());
}
}
TEST_P(CordTest, AdvanceAndReadOnSubstringDataEdge) {
RandomEngine rng(GTEST_FLAG_GET(random_seed));
const std::string data = RandomLowercaseString(&rng, 2500);
for (bool as_flat : {true, false}) {
SCOPED_TRACE(as_flat ? "Flat" : "External");
absl::Cord cord =
as_flat ? absl::Cord(data)
: absl::MakeCordFromExternal(data, [](absl::string_view) {});
cord = cord.Subcord(200, 2000);
const std::string substr = data.substr(200, 2000);
auto it = cord.Chars().begin();
#if !defined(NDEBUG) || ABSL_OPTION_HARDENED
EXPECT_DEATH_IF_SUPPORTED(cord.AdvanceAndRead(&it, 2001), ".*");
#endif
it = cord.Chars().begin();
absl::Cord frag = cord.AdvanceAndRead(&it, 2000);
EXPECT_EQ(frag, substr);
EXPECT_TRUE(it == cord.Chars().end());
it = cord.Chars().begin();
frag = cord.AdvanceAndRead(&it, 200);
EXPECT_EQ(frag, substr.substr(0, 200));
EXPECT_FALSE(it == cord.Chars().end());
frag = cord.AdvanceAndRead(&it, 1500);
EXPECT_EQ(frag, substr.substr(200, 1500));
EXPECT_FALSE(it == cord.Chars().end());
frag = cord.AdvanceAndRead(&it, 300);
EXPECT_EQ(frag, substr.substr(1700, 300));
EXPECT_TRUE(it == cord.Chars().end());
}
}
TEST_P(CordTest, CharIteratorTraits) {
static_assert(std::is_copy_constructible<absl::Cord::CharIterator>::value,
"");
static_assert(std::is_copy_assignable<absl::Cord::CharIterator>::value, "");
// Move semantics to satisfy swappable via std::swap
static_assert(std::is_move_constructible<absl::Cord::CharIterator>::value,
"");
static_assert(std::is_move_assignable<absl::Cord::CharIterator>::value, "");
static_assert(
std::is_same<
std::iterator_traits<absl::Cord::CharIterator>::iterator_category,
std::input_iterator_tag>::value,
"");
static_assert(
std::is_same<std::iterator_traits<absl::Cord::CharIterator>::value_type,
char>::value,
"");
static_assert(
std::is_same<
std::iterator_traits<absl::Cord::CharIterator>::difference_type,
ptrdiff_t>::value,
"");
static_assert(
std::is_same<std::iterator_traits<absl::Cord::CharIterator>::pointer,
const char*>::value,
"");
static_assert(
std::is_same<std::iterator_traits<absl::Cord::CharIterator>::reference,
const char&>::value,
"");
}
static void VerifyCharIterator(const absl::Cord& cord) {
EXPECT_EQ(cord.char_begin() == cord.char_end(), cord.empty());
EXPECT_EQ(cord.char_begin() != cord.char_end(), !cord.empty());
absl::Cord::CharRange range = cord.Chars();
EXPECT_EQ(range.begin() == range.end(), cord.empty());
EXPECT_EQ(range.begin() != range.end(), !cord.empty());
size_t i = 0;
absl::Cord::CharIterator pre_iter = cord.char_begin();
absl::Cord::CharIterator post_iter = cord.char_begin();
std::string content(cord);
while (pre_iter != cord.char_end() && post_iter != cord.char_end()) {
EXPECT_FALSE(pre_iter == cord.char_end()); // NOLINT: explicitly test ==
EXPECT_FALSE(post_iter == cord.char_end()); // NOLINT
EXPECT_LT(i, cord.size());
EXPECT_EQ(content[i], *pre_iter);
EXPECT_EQ(pre_iter, post_iter);
EXPECT_EQ(*pre_iter, *post_iter);
EXPECT_EQ(&*pre_iter, &*post_iter);
EXPECT_EQ(&*pre_iter, pre_iter.operator->());
const char* character_address = &*pre_iter;
absl::Cord::CharIterator copy = pre_iter;
++copy;
EXPECT_EQ(character_address, &*pre_iter);
int n_equal_iterators = 0;
for (absl::Cord::CharIterator it = range.begin(); it != range.end(); ++it) {
n_equal_iterators += static_cast<int>(it == pre_iter);
}
EXPECT_EQ(n_equal_iterators, 1);
absl::Cord::CharIterator advance_iter = range.begin();
absl::Cord::Advance(&advance_iter, i);
EXPECT_EQ(pre_iter, advance_iter);
advance_iter = range.begin();
EXPECT_EQ(absl::Cord::AdvanceAndRead(&advance_iter, i), cord.Subcord(0, i));
EXPECT_EQ(pre_iter, advance_iter);
advance_iter = pre_iter;
absl::Cord::Advance(&advance_iter, cord.size() - i);
EXPECT_EQ(range.end(), advance_iter);
advance_iter = pre_iter;
EXPECT_EQ(absl::Cord::AdvanceAndRead(&advance_iter, cord.size() - i),
cord.Subcord(i, cord.size() - i));
EXPECT_EQ(range.end(), advance_iter);
++i;
++pre_iter;
post_iter++;
}
EXPECT_EQ(i, cord.size());
EXPECT_TRUE(pre_iter == cord.char_end()); // NOLINT: explicitly test ==
EXPECT_TRUE(post_iter == cord.char_end()); // NOLINT
absl::Cord::CharIterator zero_advanced_end = cord.char_end();
absl::Cord::Advance(&zero_advanced_end, 0);
EXPECT_EQ(zero_advanced_end, cord.char_end());
absl::Cord::CharIterator it = cord.char_begin();
for (absl::string_view chunk : cord.Chunks()) {
while (!chunk.empty()) {
EXPECT_EQ(absl::Cord::ChunkRemaining(it), chunk);
chunk.remove_prefix(1);
++it;
}
}
}
TEST_P(CordTest, CharIteratorOperations) {
absl::Cord empty_cord;
VerifyCharIterator(empty_cord);
absl::Cord small_buffer_cord("small cord");
MaybeHarden(small_buffer_cord);
VerifyCharIterator(small_buffer_cord);
absl::Cord flat_node_cord("larger than small buffer optimization");
MaybeHarden(flat_node_cord);
VerifyCharIterator(flat_node_cord);
VerifyCharIterator(MaybeHardened(
absl::MakeFragmentedCord({"a ", "small ", "fragmented ", "cord ", "for ",
"testing ", "character ", "iteration."})));
absl::Cord reused_nodes_cord("ghi");
reused_nodes_cord.Prepend(absl::Cord("def"));
reused_nodes_cord.Prepend(absl::Cord("abc"));
for (int i = 0; i < 4; ++i) {
reused_nodes_cord.Prepend(reused_nodes_cord);
MaybeHarden(reused_nodes_cord);
VerifyCharIterator(reused_nodes_cord);
}
RandomEngine rng(GTEST_FLAG_GET(random_seed));
absl::Cord flat_cord(RandomLowercaseString(&rng, 256));
absl::Cord subcords;
for (int i = 0; i < 4; ++i) {
subcords.Prepend(flat_cord.Subcord(16 * i, 128));
MaybeHarden(subcords);
}
VerifyCharIterator(subcords);
}
TEST_P(CordTest, CharIteratorAdvanceAndRead) {
// Create a Cord holding 6 flats of 2500 bytes each, and then iterate over it
// reading 150, 1500, 2500 and 3000 bytes. This will result in all possible
// partial, full and straddled read combinations including reads below
// kMaxBytesToCopy. b/197776822 surfaced a bug for a specific partial, small
// read 'at end' on Cord which caused a failure on attempting to read past the
// end in CordRepBtreeReader which was not covered by any existing test.
constexpr int kBlocks = 6;
constexpr size_t kBlockSize = 2500;
constexpr size_t kChunkSize1 = 1500;
constexpr size_t kChunkSize2 = 2500;
constexpr size_t kChunkSize3 = 3000;
constexpr size_t kChunkSize4 = 150;
RandomEngine rng;
std::string data = RandomLowercaseString(&rng, kBlocks * kBlockSize);
absl::Cord cord;
for (int i = 0; i < kBlocks; ++i) {
const std::string block = data.substr(i * kBlockSize, kBlockSize);
cord.Append(absl::Cord(block));
}
MaybeHarden(cord);
for (size_t chunk_size :
{kChunkSize1, kChunkSize2, kChunkSize3, kChunkSize4}) {
absl::Cord::CharIterator it = cord.char_begin();
size_t offset = 0;
while (offset < data.length()) {
const size_t n = std::min<size_t>(data.length() - offset, chunk_size);
absl::Cord chunk = cord.AdvanceAndRead(&it, n);
ASSERT_EQ(chunk.size(), n);
ASSERT_EQ(chunk.Compare(data.substr(offset, n)), 0);
offset += n;
}
}
}
TEST_P(CordTest, StreamingOutput) {
absl::Cord c =
absl::MakeFragmentedCord({"A ", "small ", "fragmented ", "Cord", "."});
MaybeHarden(c);
std::stringstream output;
output << c;
EXPECT_EQ("A small fragmented Cord.", output.str());
}
TEST_P(CordTest, ForEachChunk) {
for (int num_elements : {1, 10, 200}) {
SCOPED_TRACE(num_elements);
std::vector<std::string> cord_chunks;
for (int i = 0; i < num_elements; ++i) {
cord_chunks.push_back(absl::StrCat("[", i, "]"));
}
absl::Cord c = absl::MakeFragmentedCord(cord_chunks);
MaybeHarden(c);
std::vector<std::string> iterated_chunks;
absl::CordTestPeer::ForEachChunk(c,
[&iterated_chunks](absl::string_view sv) {
iterated_chunks.emplace_back(sv);
});
EXPECT_EQ(iterated_chunks, cord_chunks);
}
}
TEST_P(CordTest, SmallBufferAssignFromOwnData) {
constexpr size_t kMaxInline = 15;
std::string contents = "small buff cord";
EXPECT_EQ(contents.size(), kMaxInline);
for (size_t pos = 0; pos < contents.size(); ++pos) {
for (size_t count = contents.size() - pos; count > 0; --count) {
absl::Cord c(contents);
MaybeHarden(c);
absl::string_view flat = c.Flatten();
c = flat.substr(pos, count);
EXPECT_EQ(c, contents.substr(pos, count))
<< "pos = " << pos << "; count = " << count;
}
}
}
TEST_P(CordTest, Format) {
absl::Cord c;
absl::Format(&c, "There were %04d little %s.", 3, "pigs");
EXPECT_EQ(c, "There were 0003 little pigs.");
MaybeHarden(c);
absl::Format(&c, "And %-3llx bad wolf!", 1);
MaybeHarden(c);
EXPECT_EQ(c, "There were 0003 little pigs.And 1 bad wolf!");
}
TEST_P(CordTest, Hardening) {
absl::Cord cord("hello");
MaybeHarden(cord);
// These statement should abort the program in all builds modes.
EXPECT_DEATH_IF_SUPPORTED(cord.RemovePrefix(6), "");
EXPECT_DEATH_IF_SUPPORTED(cord.RemoveSuffix(6), "");
bool test_hardening = false;
ABSL_HARDENING_ASSERT([&]() {
// This only runs when ABSL_HARDENING_ASSERT is active.
test_hardening = true;
return true;
}());
if (!test_hardening) return;
EXPECT_DEATH_IF_SUPPORTED(cord[5], "");
EXPECT_DEATH_IF_SUPPORTED(*cord.chunk_end(), "");
EXPECT_DEATH_IF_SUPPORTED(static_cast<void>(cord.chunk_end()->empty()), "");
EXPECT_DEATH_IF_SUPPORTED(++cord.chunk_end(), "");
}
// This test mimics a specific (and rare) application repeatedly splitting a
// cord, inserting (overwriting) a string value, and composing a new cord from
// the three pieces. This is hostile towards a Btree implementation: A split of
// a node at any level is likely to have the right-most edge of the left split,
// and the left-most edge of the right split shared. For example, splitting a
// leaf node with 6 edges will result likely in a 1-6, 2-5, 3-4, etc. split,
// sharing the 'split node'. When recomposing such nodes, we 'injected' an edge
// in that node. As this happens with some probability on each level of the
// tree, this will quickly grow the tree until it reaches maximum height.
TEST_P(CordTest, BtreeHostileSplitInsertJoin) {
absl::BitGen bitgen;
// Start with about 1GB of data
std::string data(1 << 10, 'x');
absl::Cord buffer(data);
absl::Cord cord;
for (int i = 0; i < 1000000; ++i) {
cord.Append(buffer);
}
for (int j = 0; j < 1000; ++j) {
MaybeHarden(cord);
size_t offset = absl::Uniform(bitgen, 0u, cord.size());
size_t length = absl::Uniform(bitgen, 100u, data.size());
if (cord.size() == offset) {
cord.Append(absl::string_view(data.data(), length));
} else {
absl::Cord suffix;
if (offset + length < cord.size()) {
suffix = cord;
suffix.RemovePrefix(offset + length);
}
if (cord.size() > offset) {
cord.RemoveSuffix(cord.size() - offset);
}
cord.Append(absl::string_view(data.data(), length));
if (!suffix.empty()) {
cord.Append(suffix);
}
}
}
}
class AfterExitCordTester {
public:
bool Set(absl::Cord* cord, absl::string_view expected) {
cord_ = cord;
expected_ = expected;
return true;
}
~AfterExitCordTester() {
EXPECT_EQ(*cord_, expected_);
}
private:
absl::Cord* cord_;
absl::string_view expected_;
};
// Deliberately prevents the destructor for an absl::Cord from running. The cord
// is accessible via the cord member during the lifetime of the CordLeaker.
// After the CordLeaker is destroyed, pointers to the cord will remain valid
// until the CordLeaker's memory is deallocated.
struct CordLeaker {
union {
absl::Cord cord;
};
template <typename Str>
constexpr explicit CordLeaker(const Str& str) : cord(str) {}
~CordLeaker() {
// Don't do anything, including running cord's destructor. (cord's
// destructor won't run automatically because cord is hidden inside a
// union.)
}
};
template <typename Str>
void TestConstinitConstructor(Str) {
const auto expected = Str::value;
// Defined before `cord` to be destroyed after it.
static AfterExitCordTester exit_tester; // NOLINT
ABSL_CONST_INIT static CordLeaker cord_leaker(Str{}); // NOLINT
// cord_leaker is static, so this reference will remain valid through the end
// of program execution.
static absl::Cord& cord = cord_leaker.cord;
static bool init_exit_tester = exit_tester.Set(&cord, expected);
(void)init_exit_tester;
EXPECT_EQ(cord, expected);
// Copy the object and test the copy, and the original.
{
absl::Cord copy = cord;
EXPECT_EQ(copy, expected);
}
// The original still works
EXPECT_EQ(cord, expected);
// Try making adding more structure to the tree.
{
absl::Cord copy = cord;
std::string expected_copy(expected);
for (int i = 0; i < 10; ++i) {
copy.Append(cord);
absl::StrAppend(&expected_copy, expected);
EXPECT_EQ(copy, expected_copy);
}
}
// Make sure we are using the right branch during constant evaluation.
EXPECT_EQ(absl::CordTestPeer::IsTree(cord), cord.size() >= 16);
for (int i = 0; i < 10; ++i) {
// Make a few more Cords from the same global rep.
// This tests what happens when the refcount for it gets below 1.
EXPECT_EQ(expected, absl::Cord(Str{}));
}
}
constexpr int SimpleStrlen(const char* p) {
return *p ? 1 + SimpleStrlen(p + 1) : 0;
}
struct ShortView {
constexpr absl::string_view operator()() const {
return absl::string_view("SSO string", SimpleStrlen("SSO string"));
}
};
struct LongView {
constexpr absl::string_view operator()() const {
return absl::string_view("String that does not fit SSO.",
SimpleStrlen("String that does not fit SSO."));
}
};
TEST_P(CordTest, ConstinitConstructor) {
TestConstinitConstructor(
absl::strings_internal::MakeStringConstant(ShortView{}));
TestConstinitConstructor(
absl::strings_internal::MakeStringConstant(LongView{}));
}
namespace {
// Test helper that generates a populated cord for future manipulation.
//
// By test convention, all generated cords begin with the characters "abcde" at
// the start of the first chunk.
class PopulatedCordFactory {
public:
constexpr PopulatedCordFactory(absl::string_view name,
absl::Cord (*generator)())
: name_(name), generator_(generator) {}
absl::string_view Name() const { return name_; }
absl::Cord Generate() const { return generator_(); }
private:
absl::string_view name_;
absl::Cord (*generator_)();
};
// clang-format off
// This array is constant-initialized in conformant compilers.
PopulatedCordFactory cord_factories[] = {
{"sso", [] { return absl::Cord("abcde"); }},
{"flat", [] {
// Too large to live in SSO space, but small enough to be a simple FLAT.
absl::Cord flat(absl::StrCat("abcde", std::string(1000, 'x')));
flat.Flatten();
return flat;
}},
{"external", [] {
// A cheat: we are using a string literal as the external storage, so a
// no-op releaser is correct here.
return absl::MakeCordFromExternal("abcde External!", []{});
}},
{"external substring", [] {
// A cheat: we are using a string literal as the external storage, so a
// no-op releaser is correct here.
absl::Cord ext = absl::MakeCordFromExternal("-abcde External!", []{});
return absl::CordTestPeer::MakeSubstring(ext, 1, ext.size() - 1);
}},
{"substring", [] {
absl::Cord flat(absl::StrCat("-abcde", std::string(1000, 'x')));
flat.Flatten();
return flat.Subcord(1, 998);
}},
{"fragmented", [] {
std::string fragment = absl::StrCat("abcde", std::string(195, 'x'));
std::vector<std::string> fragments(200, fragment);
absl::Cord cord = absl::MakeFragmentedCord(fragments);
assert(cord.size() == 40000);
return cord;
}},
};
// clang-format on
// Test helper that can mutate a cord, and possibly undo the mutation, for
// testing.
class CordMutator {
public:
constexpr CordMutator(absl::string_view name, void (*mutate)(absl::Cord&),
void (*undo)(absl::Cord&) = nullptr)
: name_(name), mutate_(mutate), undo_(undo) {}
absl::string_view Name() const { return name_; }
void Mutate(absl::Cord& cord) const { mutate_(cord); }
bool CanUndo() const { return undo_ != nullptr; }
void Undo(absl::Cord& cord) const { undo_(cord); }
private:
absl::string_view name_;
void (*mutate_)(absl::Cord&);
void (*undo_)(absl::Cord&);
};
// clang-format off
// This array is constant-initialized in conformant compilers.
CordMutator cord_mutators[] ={
{"clear", [](absl::Cord& c) { c.Clear(); }},
{"overwrite", [](absl::Cord& c) { c = "overwritten"; }},
{
"append string",
[](absl::Cord& c) { c.Append("0123456789"); },
[](absl::Cord& c) { c.RemoveSuffix(10); }
},
{
"append cord",
[](absl::Cord& c) {
c.Append(absl::MakeFragmentedCord({"12345", "67890"}));
},
[](absl::Cord& c) { c.RemoveSuffix(10); }
},
{
"append checksummed cord",
[](absl::Cord& c) {
absl::Cord to_append = absl::MakeFragmentedCord({"12345", "67890"});
to_append.SetExpectedChecksum(999);
c.Append(to_append);
},
[](absl::Cord& c) { c.RemoveSuffix(10); }
},
{
"append self",
[](absl::Cord& c) { c.Append(c); },
[](absl::Cord& c) { c.RemoveSuffix(c.size() / 2); }
},
{
"prepend string",
[](absl::Cord& c) { c.Prepend("9876543210"); },
[](absl::Cord& c) { c.RemovePrefix(10); }
},
{
"prepend cord",
[](absl::Cord& c) {
c.Prepend(absl::MakeFragmentedCord({"98765", "43210"}));
},
[](absl::Cord& c) { c.RemovePrefix(10); }
},
{
"prepend checksummed cord",
[](absl::Cord& c) {
absl::Cord to_prepend = absl::MakeFragmentedCord({"98765", "43210"});
to_prepend.SetExpectedChecksum(999);
c.Prepend(to_prepend);
},
[](absl::Cord& c) { c.RemovePrefix(10); }
},
{
"prepend self",
[](absl::Cord& c) { c.Prepend(c); },
[](absl::Cord& c) { c.RemovePrefix(c.size() / 2); }
},
{"remove prefix", [](absl::Cord& c) { c.RemovePrefix(2); }},
{"remove suffix", [](absl::Cord& c) { c.RemoveSuffix(2); }},
{"subcord", [](absl::Cord& c) { c = c.Subcord(1, c.size() - 2); }},
{
"swap inline",
[](absl::Cord& c) {
absl::Cord other("swap");
c.swap(other);
}
},
{
"swap tree",
[](absl::Cord& c) {
absl::Cord other(std::string(10000, 'x'));
c.swap(other);
}
},
};
// clang-format on
} // namespace
TEST_P(CordTest, ExpectedChecksum) {
for (const PopulatedCordFactory& factory : cord_factories) {
SCOPED_TRACE(factory.Name());
for (bool shared : {false, true}) {
SCOPED_TRACE(shared);
absl::Cord shared_cord_source = factory.Generate();
auto make_instance = [=] {
return shared ? shared_cord_source : factory.Generate();
};
const absl::Cord base_value = factory.Generate();
const std::string base_value_as_string(factory.Generate().Flatten());
absl::Cord c1 = make_instance();
EXPECT_FALSE(c1.ExpectedChecksum().has_value());
// Setting an expected checksum works, and retains the cord's bytes
c1.SetExpectedChecksum(12345);
EXPECT_EQ(c1.ExpectedChecksum().value_or(0), 12345);
EXPECT_EQ(c1, base_value);
// CRC persists through copies, assignments, and moves:
absl::Cord c1_copy_construct = c1;
EXPECT_EQ(c1_copy_construct.ExpectedChecksum().value_or(0), 12345);
absl::Cord c1_copy_assign;
c1_copy_assign = c1;
EXPECT_EQ(c1_copy_assign.ExpectedChecksum().value_or(0), 12345);
absl::Cord c1_move(std::move(c1_copy_assign));
EXPECT_EQ(c1_move.ExpectedChecksum().value_or(0), 12345);
EXPECT_EQ(c1.ExpectedChecksum().value_or(0), 12345);
// A CRC Cord compares equal to its non-CRC value.
EXPECT_EQ(c1, make_instance());
for (const CordMutator& mutator : cord_mutators) {
SCOPED_TRACE(mutator.Name());
// Test that mutating a cord removes its stored checksum
absl::Cord c2 = make_instance();
c2.SetExpectedChecksum(24680);
mutator.Mutate(c2);
EXPECT_EQ(c2.ExpectedChecksum(), absl::nullopt);
if (mutator.CanUndo()) {
// Undoing an operation should not restore the checksum
mutator.Undo(c2);
EXPECT_EQ(c2, base_value);
EXPECT_EQ(c2.ExpectedChecksum(), absl::nullopt);
}
}
absl::Cord c3 = make_instance();
c3.SetExpectedChecksum(999);
const absl::Cord& cc3 = c3;
// Test that all cord reading operations function in the face of an
// expected checksum.
// Test data precondition
ASSERT_TRUE(cc3.StartsWith("abcde"));
EXPECT_EQ(cc3.size(), base_value_as_string.size());
EXPECT_FALSE(cc3.empty());
EXPECT_EQ(cc3.Compare(base_value), 0);
EXPECT_EQ(cc3.Compare(base_value_as_string), 0);
EXPECT_EQ(cc3.Compare("wxyz"), -1);
EXPECT_EQ(cc3.Compare(absl::Cord("wxyz")), -1);
EXPECT_EQ(cc3.Compare("aaaa"), 1);
EXPECT_EQ(cc3.Compare(absl::Cord("aaaa")), 1);
EXPECT_EQ(absl::Cord("wxyz").Compare(cc3), 1);
EXPECT_EQ(absl::Cord("aaaa").Compare(cc3), -1);
EXPECT_TRUE(cc3.StartsWith("abcd"));
EXPECT_EQ(std::string(cc3), base_value_as_string);
std::string dest;
absl::CopyCordToString(cc3, &dest);
EXPECT_EQ(dest, base_value_as_string);
bool first_pass = true;
for (absl::string_view chunk : cc3.Chunks()) {
if (first_pass) {
EXPECT_TRUE(absl::StartsWith(chunk, "abcde"));
}
first_pass = false;
}
first_pass = true;
for (char ch : cc3.Chars()) {
if (first_pass) {
EXPECT_EQ(ch, 'a');
}
first_pass = false;
}
EXPECT_TRUE(absl::StartsWith(*cc3.chunk_begin(), "abcde"));
EXPECT_EQ(*cc3.char_begin(), 'a');
auto char_it = cc3.char_begin();
absl::Cord::Advance(&char_it, 2);
EXPECT_EQ(absl::Cord::AdvanceAndRead(&char_it, 2), "cd");
EXPECT_EQ(*char_it, 'e');
char_it = cc3.char_begin();
absl::Cord::Advance(&char_it, 2);
EXPECT_TRUE(absl::StartsWith(absl::Cord::ChunkRemaining(char_it), "cde"));
EXPECT_EQ(cc3[0], 'a');
EXPECT_EQ(cc3[4], 'e');
EXPECT_EQ(absl::HashOf(cc3), absl::HashOf(base_value));
EXPECT_EQ(absl::HashOf(cc3), absl::HashOf(base_value_as_string));
}
}
}