folly/io/test/IOBufTest.cpp

   1 /*
   2  * Copyright 2016 Facebook, Inc.
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the "License");
   5  * you may not use this file except in compliance with the License.
   6  * You may obtain a copy of the License at
   7  *
   8  *   http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  */
  16
  17 #include <folly/io/IOBuf.h>
  18 #include <folly/io/TypedIOBuf.h>
  19
  20 #include <cstddef>
  21
  22 #include <boost/random.hpp>
  23 #include <gtest/gtest.h>
  24
  25 #include <folly/Malloc.h>
  26 #include <folly/Range.h>
  27
  28 using folly::fbstring;
  29 using folly::fbvector;
  30 using folly::IOBuf;
  31 using folly::TypedIOBuf;
  32 using folly::StringPiece;
  33 using folly::ByteRange;
  34 using std::unique_ptr;
  35
  36 void append(std::unique_ptr<IOBuf>& buf, StringPiece str) {
  37   EXPECT_LE(str.size(), buf->tailroom());
  38   memcpy(buf->writableData(), str.data(), str.size());
  39   buf->append(str.size());
  40 }
  41
  42 void prepend(std::unique_ptr<IOBuf>& buf, StringPiece str) {
  43   EXPECT_LE(str.size(), buf->headroom());
  44   memcpy(buf->writableData() - str.size(), str.data(), str.size());
  45   buf->prepend(str.size());
  46 }
  47
  48 TEST(IOBuf, Simple) {
  49   unique_ptr<IOBuf> buf(IOBuf::create(100));
  50   uint32_t cap = buf->capacity();
  51   EXPECT_LE(100, cap);
  52   EXPECT_EQ(0, buf->headroom());
  53   EXPECT_EQ(0, buf->length());
  54   EXPECT_EQ(cap, buf->tailroom());
  55
  56   append(buf, "world");
  57   buf->advance(10);
  58   EXPECT_EQ(10, buf->headroom());
  59   EXPECT_EQ(5, buf->length());
  60   EXPECT_EQ(cap - 15, buf->tailroom());
  61
  62   prepend(buf, "hello ");
  63   EXPECT_EQ(4, buf->headroom());
  64   EXPECT_EQ(11, buf->length());
  65   EXPECT_EQ(cap - 15, buf->tailroom());
  66
  67   const char* p = reinterpret_cast<const char*>(buf->data());
  68   EXPECT_EQ("hello world", std::string(p, buf->length()));
  69
  70   buf->clear();
  71   EXPECT_EQ(0, buf->headroom());
  72   EXPECT_EQ(0, buf->length());
  73   EXPECT_EQ(cap, buf->tailroom());
  74 }
  75
  76
  77 void testAllocSize(uint32_t requestedCapacity) {
  78   unique_ptr<IOBuf> iobuf(IOBuf::create(requestedCapacity));
  79   EXPECT_GE(iobuf->capacity(), requestedCapacity);
  80 }
  81
  82 TEST(IOBuf, AllocSizes) {
  83   // Try with a small allocation size that should fit in the internal buffer
  84   testAllocSize(28);
  85
  86   // Try with a large allocation size that will require an external buffer.
  87   testAllocSize(9000);
  88
  89   // 220 bytes is currently the cutoff
  90   // (It would be nice to use the IOBuf::kMaxInternalDataSize constant,
  91   // but it's private and it doesn't seem worth making it public just for this
  92   // test code.)
  93   testAllocSize(220);
  94   testAllocSize(219);
  95   testAllocSize(221);
  96 }
  97
  98 void deleteArrayBuffer(void *buf, void* arg) {
  99   uint32_t* deleteCount = static_cast<uint32_t*>(arg);
 100   ++(*deleteCount);
 101   uint8_t* bufPtr = static_cast<uint8_t*>(buf);
 102   delete[] bufPtr;
 103 }
 104
 105 TEST(IOBuf, TakeOwnership) {
 106   uint32_t size1 = 99;
 107   uint8_t *buf1 = static_cast<uint8_t*>(malloc(size1));
 108   unique_ptr<IOBuf> iobuf1(IOBuf::takeOwnership(buf1, size1));
 109   EXPECT_EQ(buf1, iobuf1->data());
 110   EXPECT_EQ(size1, iobuf1->length());
 111   EXPECT_EQ(buf1, iobuf1->buffer());
 112   EXPECT_EQ(size1, iobuf1->capacity());
 113
 114   uint32_t deleteCount = 0;
 115   uint32_t size2 = 4321;
 116   uint8_t *buf2 = new uint8_t[size2];
 117   unique_ptr<IOBuf> iobuf2(IOBuf::takeOwnership(buf2, size2,
 118                                                 deleteArrayBuffer,
 119                                                 &deleteCount));
 120   EXPECT_EQ(buf2, iobuf2->data());
 121   EXPECT_EQ(size2, iobuf2->length());
 122   EXPECT_EQ(buf2, iobuf2->buffer());
 123   EXPECT_EQ(size2, iobuf2->capacity());
 124   EXPECT_EQ(0, deleteCount);
 125   iobuf2.reset();
 126   EXPECT_EQ(1, deleteCount);
 127
 128   deleteCount = 0;
 129   uint32_t size3 = 3456;
 130   uint8_t *buf3 = new uint8_t[size3];
 131   uint32_t length3 = 48;
 132   unique_ptr<IOBuf> iobuf3(IOBuf::takeOwnership(buf3, size3, length3,
 133                                                 deleteArrayBuffer,
 134                                                 &deleteCount));
 135   EXPECT_EQ(buf3, iobuf3->data());
 136   EXPECT_EQ(length3, iobuf3->length());
 137   EXPECT_EQ(buf3, iobuf3->buffer());
 138   EXPECT_EQ(size3, iobuf3->capacity());
 139   EXPECT_EQ(0, deleteCount);
 140   iobuf3.reset();
 141   EXPECT_EQ(1, deleteCount);
 142
 143   deleteCount = 0;
 144   {
 145     uint32_t size4 = 1234;
 146     uint8_t *buf4 = new uint8_t[size4];
 147     uint32_t length4 = 48;
 148     IOBuf iobuf4(IOBuf::TAKE_OWNERSHIP, buf4, size4, length4,
 149                  deleteArrayBuffer, &deleteCount);
 150     EXPECT_EQ(buf4, iobuf4.data());
 151     EXPECT_EQ(length4, iobuf4.length());
 152     EXPECT_EQ(buf4, iobuf4.buffer());
 153     EXPECT_EQ(size4, iobuf4.capacity());
 154
 155     IOBuf iobuf5 = std::move(iobuf4);
 156     EXPECT_EQ(buf4, iobuf5.data());
 157     EXPECT_EQ(length4, iobuf5.length());
 158     EXPECT_EQ(buf4, iobuf5.buffer());
 159     EXPECT_EQ(size4, iobuf5.capacity());
 160     EXPECT_EQ(0, deleteCount);
 161   }
 162   EXPECT_EQ(1, deleteCount);
 163 }
 164
 165 TEST(IOBuf, WrapBuffer) {
 166   const uint32_t size1 = 1234;
 167   uint8_t buf1[size1];
 168   unique_ptr<IOBuf> iobuf1(IOBuf::wrapBuffer(buf1, size1));
 169   EXPECT_EQ(buf1, iobuf1->data());
 170   EXPECT_EQ(size1, iobuf1->length());
 171   EXPECT_EQ(buf1, iobuf1->buffer());
 172   EXPECT_EQ(size1, iobuf1->capacity());
 173
 174   uint32_t size2 = 0x1234;
 175   unique_ptr<uint8_t[]> buf2(new uint8_t[size2]);
 176   unique_ptr<IOBuf> iobuf2(IOBuf::wrapBuffer(buf2.get(), size2));
 177   EXPECT_EQ(buf2.get(), iobuf2->data());
 178   EXPECT_EQ(size2, iobuf2->length());
 179   EXPECT_EQ(buf2.get(), iobuf2->buffer());
 180   EXPECT_EQ(size2, iobuf2->capacity());
 181
 182   uint32_t size3 = 4321;
 183   unique_ptr<uint8_t[]> buf3(new uint8_t[size3]);
 184   IOBuf iobuf3(IOBuf::WRAP_BUFFER, buf3.get(), size3);
 185   EXPECT_EQ(buf3.get(), iobuf3.data());
 186   EXPECT_EQ(size3, iobuf3.length());
 187   EXPECT_EQ(buf3.get(), iobuf3.buffer());
 188   EXPECT_EQ(size3, iobuf3.capacity());
 189 }
 190
 191 TEST(IOBuf, CreateCombined) {
 192   // Create a combined IOBuf, then destroy it.
 193   // The data buffer and IOBuf both become unused as part of the destruction
 194   {
 195     auto buf = IOBuf::createCombined(256);
 196     EXPECT_FALSE(buf->isShared());
 197   }
 198
 199   // Create a combined IOBuf, clone from it, and then destroy the original
 200   // IOBuf.  The data buffer cannot be deleted until the clone is also
 201   // destroyed.
 202   {
 203     auto bufA = IOBuf::createCombined(256);
 204     EXPECT_FALSE(bufA->isShared());
 205     auto bufB = bufA->clone();
 206     EXPECT_TRUE(bufA->isShared());
 207     EXPECT_TRUE(bufB->isShared());
 208     bufA.reset();
 209     EXPECT_FALSE(bufB->isShared());
 210   }
 211
 212   // Create a combined IOBuf, then call reserve() to get a larger buffer.
 213   // The IOBuf no longer points to the combined data buffer, but the
 214   // overall memory segment cannot be deleted until the IOBuf is also
 215   // destroyed.
 216   {
 217     auto buf = IOBuf::createCombined(256);
 218     buf->reserve(0, buf->capacity() + 100);
 219   }
 220
 221   // Create a combined IOBuf, clone from it, then call unshare() on the original
 222   // buffer.  This creates a situation where bufB is pointing at the combined
 223   // buffer associated with bufA, but bufA is now using a different buffer.
 224   auto testSwap = [](bool resetAFirst) {
 225     auto bufA = IOBuf::createCombined(256);
 226     EXPECT_FALSE(bufA->isShared());
 227     auto bufB = bufA->clone();
 228     EXPECT_TRUE(bufA->isShared());
 229     EXPECT_TRUE(bufB->isShared());
 230     bufA->unshare();
 231     EXPECT_FALSE(bufA->isShared());
 232     EXPECT_FALSE(bufB->isShared());
 233
 234     if (resetAFirst) {
 235       bufA.reset();
 236       bufB.reset();
 237     } else {
 238       bufB.reset();
 239       bufA.reset();
 240     }
 241   };
 242   testSwap(true);
 243   testSwap(false);
 244 }
 245
 246 void fillBuf(uint8_t* buf, uint32_t length, boost::mt19937& gen) {
 247   for (uint32_t n = 0; n < length; ++n) {
 248     buf[n] = static_cast<uint8_t>(gen() & 0xff);
 249   }
 250 }
 251
 252 void fillBuf(IOBuf* buf, boost::mt19937& gen) {
 253   buf->unshare();
 254   fillBuf(buf->writableData(), buf->length(), gen);
 255 }
 256
 257 void checkBuf(const uint8_t* buf, uint32_t length, boost::mt19937& gen) {
 258   // Rather than using EXPECT_EQ() to check each character,
 259   // count the number of differences and the first character that differs.
 260   // This way on error we'll report just that information, rather than tons of
 261   // failed checks for each byte in the buffer.
 262   uint32_t numDifferences = 0;
 263   uint32_t firstDiffIndex = 0;
 264   uint8_t firstDiffExpected = 0;
 265   for (uint32_t n = 0; n < length; ++n) {
 266     uint8_t expected = static_cast<uint8_t>(gen() & 0xff);
 267     if (buf[n] == expected) {
 268       continue;
 269     }
 270
 271     if (numDifferences == 0) {
 272       firstDiffIndex = n;
 273       firstDiffExpected = expected;
 274     }
 275     ++numDifferences;
 276   }
 277
 278   EXPECT_EQ(0, numDifferences);
 279   if (numDifferences > 0) {
 280     // Cast to int so it will be printed numerically
 281     // rather than as a char if the check fails
 282     EXPECT_EQ(static_cast<int>(buf[firstDiffIndex]),
 283               static_cast<int>(firstDiffExpected));
 284   }
 285 }
 286
 287 void checkBuf(IOBuf* buf, boost::mt19937& gen) {
 288   checkBuf(buf->data(), buf->length(), gen);
 289 }
 290
 291 void checkBuf(ByteRange buf, boost::mt19937& gen) {
 292   checkBuf(buf.data(), buf.size(), gen);
 293 }
 294
 295 void checkChain(IOBuf* buf, boost::mt19937& gen) {
 296   IOBuf *current = buf;
 297   do {
 298     checkBuf(current->data(), current->length(), gen);
 299     current = current->next();
 300   } while (current != buf);
 301 }
 302
 303 TEST(IOBuf, Chaining) {
 304   uint32_t fillSeed = 0x12345678;
 305   boost::mt19937 gen(fillSeed);
 306
 307   // An IOBuf with external storage
 308   uint32_t headroom = 123;
 309   unique_ptr<IOBuf> iob1(IOBuf::create(2048));
 310   iob1->advance(headroom);
 311   iob1->append(1500);
 312   fillBuf(iob1.get(), gen);
 313
 314   // An IOBuf with internal storage
 315   unique_ptr<IOBuf> iob2(IOBuf::create(20));
 316   iob2->append(20);
 317   fillBuf(iob2.get(), gen);
 318
 319   // An IOBuf around a buffer it doesn't own
 320   uint8_t localbuf[1234];
 321   fillBuf(localbuf, 1234, gen);
 322   unique_ptr<IOBuf> iob3(IOBuf::wrapBuffer(localbuf, sizeof(localbuf)));
 323
 324   // An IOBuf taking ownership of a user-supplied buffer
 325   uint32_t heapBufSize = 900;
 326   uint8_t* heapBuf = static_cast<uint8_t*>(malloc(heapBufSize));
 327   fillBuf(heapBuf, heapBufSize, gen);
 328   unique_ptr<IOBuf> iob4(IOBuf::takeOwnership(heapBuf, heapBufSize));
 329
 330   // An IOBuf taking ownership of a user-supplied buffer with
 331   // a custom free function
 332   uint32_t arrayBufSize = 321;
 333   uint8_t* arrayBuf = new uint8_t[arrayBufSize];
 334   fillBuf(arrayBuf, arrayBufSize, gen);
 335   uint32_t arrayBufFreeCount = 0;
 336   unique_ptr<IOBuf> iob5(IOBuf::takeOwnership(arrayBuf, arrayBufSize,
 337                                               deleteArrayBuffer,
 338                                               &arrayBufFreeCount));
 339
 340   EXPECT_FALSE(iob1->isChained());
 341   EXPECT_FALSE(iob2->isChained());
 342   EXPECT_FALSE(iob3->isChained());
 343   EXPECT_FALSE(iob4->isChained());
 344   EXPECT_FALSE(iob5->isChained());
 345
 346   EXPECT_FALSE(iob1->isSharedOne());
 347   EXPECT_FALSE(iob2->isSharedOne());
 348   EXPECT_TRUE(iob3->isSharedOne()); // since we own the buffer
 349   EXPECT_FALSE(iob4->isSharedOne());
 350   EXPECT_FALSE(iob5->isSharedOne());
 351
 352   // Chain the buffers all together
 353   // Since we are going to relinquish ownership of iob2-5 to the chain,
 354   // store raw pointers to them so we can reference them later.
 355   IOBuf* iob2ptr = iob2.get();
 356   IOBuf* iob3ptr = iob3.get();
 357   IOBuf* iob4ptr = iob4.get();
 358   IOBuf* iob5ptr = iob5.get();
 359
 360   iob1->prependChain(std::move(iob2));
 361   iob1->prependChain(std::move(iob4));
 362   iob2ptr->appendChain(std::move(iob3));
 363   iob1->prependChain(std::move(iob5));
 364
 365   EXPECT_EQ(iob2ptr, iob1->next());
 366   EXPECT_EQ(iob3ptr, iob2ptr->next());
 367   EXPECT_EQ(iob4ptr, iob3ptr->next());
 368   EXPECT_EQ(iob5ptr, iob4ptr->next());
 369   EXPECT_EQ(iob1.get(), iob5ptr->next());
 370
 371   EXPECT_EQ(iob5ptr, iob1->prev());
 372   EXPECT_EQ(iob1.get(), iob2ptr->prev());
 373   EXPECT_EQ(iob2ptr, iob3ptr->prev());
 374   EXPECT_EQ(iob3ptr, iob4ptr->prev());
 375   EXPECT_EQ(iob4ptr, iob5ptr->prev());
 376
 377   EXPECT_TRUE(iob1->isChained());
 378   EXPECT_TRUE(iob2ptr->isChained());
 379   EXPECT_TRUE(iob3ptr->isChained());
 380   EXPECT_TRUE(iob4ptr->isChained());
 381   EXPECT_TRUE(iob5ptr->isChained());
 382
 383   uint64_t fullLength = (iob1->length() + iob2ptr->length() +
 384                          iob3ptr->length() + iob4ptr->length() +
 385                         iob5ptr->length());
 386   EXPECT_EQ(5, iob1->countChainElements());
 387   EXPECT_EQ(fullLength, iob1->computeChainDataLength());
 388
 389   // Since iob3 is shared, the entire buffer should report itself as shared
 390   EXPECT_TRUE(iob1->isShared());
 391   // Unshare just iob3
 392   iob3ptr->unshareOne();
 393   EXPECT_FALSE(iob3ptr->isSharedOne());
 394   // Now everything in the chain should be unshared.
 395   // Check on all members of the chain just for good measure
 396   EXPECT_FALSE(iob1->isShared());
 397   EXPECT_FALSE(iob2ptr->isShared());
 398   EXPECT_FALSE(iob3ptr->isShared());
 399   EXPECT_FALSE(iob4ptr->isShared());
 400   EXPECT_FALSE(iob5ptr->isShared());
 401
 402   // Check iteration
 403   gen.seed(fillSeed);
 404   size_t count = 0;
 405   for (auto buf : *iob1) {
 406     checkBuf(buf, gen);
 407     ++count;
 408   }
 409   EXPECT_EQ(5, count);
 410
 411   // Clone one of the IOBufs in the chain
 412   unique_ptr<IOBuf> iob4clone = iob4ptr->cloneOne();
 413   gen.seed(fillSeed);
 414   checkBuf(iob1.get(), gen);
 415   checkBuf(iob2ptr, gen);
 416   checkBuf(iob3ptr, gen);
 417   checkBuf(iob4clone.get(), gen);
 418   checkBuf(iob5ptr, gen);
 419
 420   EXPECT_TRUE(iob1->isShared());
 421   EXPECT_TRUE(iob2ptr->isShared());
 422   EXPECT_TRUE(iob3ptr->isShared());
 423   EXPECT_TRUE(iob4ptr->isShared());
 424   EXPECT_TRUE(iob5ptr->isShared());
 425
 426   EXPECT_FALSE(iob1->isSharedOne());
 427   EXPECT_FALSE(iob2ptr->isSharedOne());
 428   EXPECT_FALSE(iob3ptr->isSharedOne());
 429   EXPECT_TRUE(iob4ptr->isSharedOne());
 430   EXPECT_FALSE(iob5ptr->isSharedOne());
 431
 432   // Unshare that clone
 433   EXPECT_TRUE(iob4clone->isSharedOne());
 434   iob4clone->unshare();
 435   EXPECT_FALSE(iob4clone->isSharedOne());
 436   EXPECT_FALSE(iob4ptr->isSharedOne());
 437   EXPECT_FALSE(iob1->isShared());
 438   iob4clone.reset();
 439
 440
 441   // Create a clone of a different IOBuf
 442   EXPECT_FALSE(iob1->isShared());
 443   EXPECT_FALSE(iob3ptr->isSharedOne());
 444
 445   unique_ptr<IOBuf> iob3clone = iob3ptr->cloneOne();
 446   gen.seed(fillSeed);
 447   checkBuf(iob1.get(), gen);
 448   checkBuf(iob2ptr, gen);
 449   checkBuf(iob3clone.get(), gen);
 450   checkBuf(iob4ptr, gen);
 451   checkBuf(iob5ptr, gen);
 452
 453   EXPECT_TRUE(iob1->isShared());
 454   EXPECT_TRUE(iob3ptr->isSharedOne());
 455   EXPECT_FALSE(iob1->isSharedOne());
 456
 457   // Delete the clone and make sure the original is unshared
 458   iob3clone.reset();
 459   EXPECT_FALSE(iob1->isShared());
 460   EXPECT_FALSE(iob3ptr->isSharedOne());
 461
 462
 463   // Clone the entire chain
 464   unique_ptr<IOBuf> chainClone = iob1->clone();
 465   // Verify that the data is correct.
 466   EXPECT_EQ(fullLength, chainClone->computeChainDataLength());
 467   gen.seed(fillSeed);
 468   checkChain(chainClone.get(), gen);
 469
 470   // Check that the buffers report sharing correctly
 471   EXPECT_TRUE(chainClone->isShared());
 472   EXPECT_TRUE(iob1->isShared());
 473
 474   EXPECT_TRUE(iob1->isSharedOne());
 475   EXPECT_TRUE(iob2ptr->isSharedOne());
 476   EXPECT_TRUE(iob3ptr->isSharedOne());
 477   EXPECT_TRUE(iob4ptr->isSharedOne());
 478   EXPECT_TRUE(iob5ptr->isSharedOne());
 479
 480   // Unshare the cloned chain
 481   chainClone->unshare();
 482   EXPECT_FALSE(chainClone->isShared());
 483   EXPECT_FALSE(iob1->isShared());
 484
 485   // Make sure the unshared result still has the same data
 486   EXPECT_EQ(fullLength, chainClone->computeChainDataLength());
 487   gen.seed(fillSeed);
 488   checkChain(chainClone.get(), gen);
 489
 490   // Destroy this chain
 491   chainClone.reset();
 492
 493
 494   // Clone a new chain
 495   EXPECT_FALSE(iob1->isShared());
 496   chainClone = iob1->clone();
 497   EXPECT_TRUE(iob1->isShared());
 498   EXPECT_TRUE(chainClone->isShared());
 499
 500   // Delete the original chain
 501   iob1.reset();
 502   EXPECT_FALSE(chainClone->isShared());
 503
 504   // Coalesce the chain
 505   //
 506   // Coalescing this chain will create a new buffer and release the last
 507   // refcount on the original buffers we created.  Also make sure
 508   // that arrayBufFreeCount increases to one to indicate that arrayBuf was
 509   // freed.
 510   EXPECT_EQ(5, chainClone->countChainElements());
 511   EXPECT_EQ(0, arrayBufFreeCount);
 512
 513   // Buffer lengths: 1500 20 1234 900 321
 514   // Attempting to gather more data than available should fail
 515   EXPECT_THROW(chainClone->gather(4000), std::overflow_error);
 516   // Coalesce the first 3 buffers
 517   chainClone->gather(1521);
 518   EXPECT_EQ(3, chainClone->countChainElements());
 519   EXPECT_EQ(0, arrayBufFreeCount);
 520
 521   // Make sure the data is still the same after coalescing
 522   EXPECT_EQ(fullLength, chainClone->computeChainDataLength());
 523   gen.seed(fillSeed);
 524   checkChain(chainClone.get(), gen);
 525
 526   // Coalesce the entire chain
 527   chainClone->coalesce();
 528   EXPECT_EQ(1, chainClone->countChainElements());
 529   EXPECT_EQ(1, arrayBufFreeCount);
 530
 531   // Make sure the data is still the same after coalescing
 532   EXPECT_EQ(fullLength, chainClone->computeChainDataLength());
 533   gen.seed(fillSeed);
 534   checkChain(chainClone.get(), gen);
 535
 536   // Make a new chain to test the unlink and pop operations
 537   iob1 = IOBuf::create(1);
 538   iob1->append(1);
 539   IOBuf *iob1ptr = iob1.get();
 540   iob2 = IOBuf::create(3);
 541   iob2->append(3);
 542   iob2ptr = iob2.get();
 543   iob3 = IOBuf::create(5);
 544   iob3->append(5);
 545   iob3ptr = iob3.get();
 546   iob4 = IOBuf::create(7);
 547   iob4->append(7);
 548   iob4ptr = iob4.get();
 549   iob1->appendChain(std::move(iob2));
 550   iob1->prev()->appendChain(std::move(iob3));
 551   iob1->prev()->appendChain(std::move(iob4));
 552   EXPECT_EQ(4, iob1->countChainElements());
 553   EXPECT_EQ(16, iob1->computeChainDataLength());
 554
 555   // Unlink from the middle of the chain
 556   iob3 = iob3ptr->unlink();
 557   EXPECT_TRUE(iob3.get() == iob3ptr);
 558   EXPECT_EQ(3, iob1->countChainElements());
 559   EXPECT_EQ(11, iob1->computeChainDataLength());
 560
 561   // Unlink from the end of the chain
 562   iob4 = iob1->prev()->unlink();
 563   EXPECT_TRUE(iob4.get() == iob4ptr);
 564   EXPECT_EQ(2, iob1->countChainElements());
 565   EXPECT_TRUE(iob1->next() == iob2ptr);
 566   EXPECT_EQ(4, iob1->computeChainDataLength());
 567
 568   // Pop from the front of the chain
 569   iob2 = iob1->pop();
 570   EXPECT_TRUE(iob1.get() == iob1ptr);
 571   EXPECT_EQ(1, iob1->countChainElements());
 572   EXPECT_EQ(1, iob1->computeChainDataLength());
 573   EXPECT_TRUE(iob2.get() == iob2ptr);
 574   EXPECT_EQ(1, iob2->countChainElements());
 575   EXPECT_EQ(3, iob2->computeChainDataLength());
 576 }
 577
 578 void testFreeFn(void* buffer, void* ptr) {
 579   uint32_t* freeCount = static_cast<uint32_t*>(ptr);;
 580   delete[] static_cast<uint8_t*>(buffer);
 581   if (freeCount) {
 582     ++(*freeCount);
 583   }
 584 };
 585
 586 TEST(IOBuf, Reserve) {
 587   uint32_t fillSeed = 0x23456789;
 588   boost::mt19937 gen(fillSeed);
 589
 590   // Reserve does nothing if empty and doesn't have to grow the buffer
 591   {
 592     gen.seed(fillSeed);
 593     unique_ptr<IOBuf> iob(IOBuf::create(2000));
 594     EXPECT_EQ(0, iob->headroom());
 595     const void* p1 = iob->buffer();
 596     iob->reserve(5, 15);
 597     EXPECT_LE(5, iob->headroom());
 598     EXPECT_EQ(p1, iob->buffer());
 599   }
 600
 601   // Reserve doesn't reallocate if we have enough total room
 602   {
 603     gen.seed(fillSeed);
 604     unique_ptr<IOBuf> iob(IOBuf::create(2000));
 605     iob->append(100);
 606     fillBuf(iob.get(), gen);
 607     EXPECT_EQ(0, iob->headroom());
 608     EXPECT_EQ(100, iob->length());
 609     const void* p1 = iob->buffer();
 610     const uint8_t* d1 = iob->data();
 611     iob->reserve(100, 1800);
 612     EXPECT_LE(100, iob->headroom());
 613     EXPECT_EQ(p1, iob->buffer());
 614     EXPECT_EQ(d1 + 100, iob->data());
 615     gen.seed(fillSeed);
 616     checkBuf(iob.get(), gen);
 617   }
 618
 619   // Reserve reallocates if we don't have enough total room.
 620   // NOTE that, with jemalloc, we know that this won't reallocate in place
 621   // as the size is less than jemallocMinInPlaceExpanadable
 622   {
 623     gen.seed(fillSeed);
 624     unique_ptr<IOBuf> iob(IOBuf::create(2000));
 625     iob->append(100);
 626     fillBuf(iob.get(), gen);
 627     EXPECT_EQ(0, iob->headroom());
 628     EXPECT_EQ(100, iob->length());
 629     const void* p1 = iob->buffer();
 630     iob->reserve(100, 2512);  // allocation sizes are multiples of 256
 631     EXPECT_LE(100, iob->headroom());
 632     if (folly::usingJEMalloc()) {
 633       EXPECT_NE(p1, iob->buffer());
 634     }
 635     gen.seed(fillSeed);
 636     checkBuf(iob.get(), gen);
 637   }
 638
 639   // Test reserve from internal buffer, this used to segfault
 640   {
 641     unique_ptr<IOBuf> iob(IOBuf::create(0));
 642     iob->reserve(0, 2000);
 643     EXPECT_EQ(0, iob->headroom());
 644     EXPECT_LE(2000, iob->tailroom());
 645   }
 646
 647   // Test reserving from a user-allocated buffer.
 648   {
 649     uint8_t* buf = static_cast<uint8_t*>(malloc(100));
 650     auto iob = IOBuf::takeOwnership(buf, 100);
 651     iob->reserve(0, 2000);
 652     EXPECT_EQ(0, iob->headroom());
 653     EXPECT_LE(2000, iob->tailroom());
 654   }
 655
 656   // Test reserving from a user-allocated with a custom free function.
 657   {
 658     uint32_t freeCount{0};
 659     uint8_t* buf = new uint8_t[100];
 660     auto iob = IOBuf::takeOwnership(buf, 100, testFreeFn, &freeCount);
 661     iob->reserve(0, 2000);
 662     EXPECT_EQ(0, iob->headroom());
 663     EXPECT_LE(2000, iob->tailroom());
 664     EXPECT_EQ(1, freeCount);
 665   }
 666 }
 667
 668 TEST(IOBuf, copyBuffer) {
 669   std::string s("hello");
 670   auto buf = IOBuf::copyBuffer(s.data(), s.size(), 1, 2);
 671   EXPECT_EQ(1, buf->headroom());
 672   EXPECT_EQ(s, std::string(reinterpret_cast<const char*>(buf->data()),
 673                            buf->length()));
 674   EXPECT_LE(2, buf->tailroom());
 675
 676   buf = IOBuf::copyBuffer(s, 5, 7);
 677   EXPECT_EQ(5, buf->headroom());
 678   EXPECT_EQ(s, std::string(reinterpret_cast<const char*>(buf->data()),
 679                            buf->length()));
 680   EXPECT_LE(7, buf->tailroom());
 681
 682   std::string empty;
 683   buf = IOBuf::copyBuffer(empty, 3, 6);
 684   EXPECT_EQ(3, buf->headroom());
 685   EXPECT_EQ(0, buf->length());
 686   EXPECT_LE(6, buf->tailroom());
 687
 688   // A stack-allocated version
 689   IOBuf stackBuf(IOBuf::COPY_BUFFER, s, 1, 2);
 690   EXPECT_EQ(1, stackBuf.headroom());
 691   EXPECT_EQ(s, std::string(reinterpret_cast<const char*>(stackBuf.data()),
 692                            stackBuf.length()));
 693   EXPECT_LE(2, stackBuf.tailroom());
 694 }
 695
 696 TEST(IOBuf, maybeCopyBuffer) {
 697   std::string s("this is a test");
 698   auto buf = IOBuf::maybeCopyBuffer(s, 1, 2);
 699   EXPECT_EQ(1, buf->headroom());
 700   EXPECT_EQ(s, std::string(reinterpret_cast<const char*>(buf->data()),
 701                            buf->length()));
 702   EXPECT_LE(2, buf->tailroom());
 703
 704   std::string empty;
 705   buf = IOBuf::maybeCopyBuffer("", 5, 7);
 706   EXPECT_EQ(nullptr, buf.get());
 707
 708   buf = IOBuf::maybeCopyBuffer("");
 709   EXPECT_EQ(nullptr, buf.get());
 710 }
 711
 712 namespace {
 713
 714 int customDeleterCount = 0;
 715 int destructorCount = 0;
 716 struct OwnershipTestClass {
 717   explicit OwnershipTestClass(int v = 0) : val(v) { }
 718   ~OwnershipTestClass() {
 719     ++destructorCount;
 720   }
 721   int val;
 722 };
 723
 724 typedef std::function<void(OwnershipTestClass*)> CustomDeleter;
 725
 726 void customDelete(OwnershipTestClass* p) {
 727   ++customDeleterCount;
 728   delete p;
 729 }
 730
 731 void customDeleteArray(OwnershipTestClass* p) {
 732   ++customDeleterCount;
 733   delete[] p;
 734 }
 735
 736 }  // namespace
 737
 738 TEST(IOBuf, takeOwnershipUniquePtr) {
 739   destructorCount = 0;
 740   {
 741     std::unique_ptr<OwnershipTestClass> p(new OwnershipTestClass());
 742   }
 743   EXPECT_EQ(1, destructorCount);
 744
 745   destructorCount = 0;
 746   {
 747     std::unique_ptr<OwnershipTestClass[]> p(new OwnershipTestClass[2]);
 748   }
 749   EXPECT_EQ(2, destructorCount);
 750
 751   destructorCount = 0;
 752   {
 753     std::unique_ptr<OwnershipTestClass> p(new OwnershipTestClass());
 754     std::unique_ptr<IOBuf> buf(IOBuf::takeOwnership(std::move(p)));
 755     EXPECT_EQ(sizeof(OwnershipTestClass), buf->length());
 756     EXPECT_EQ(0, destructorCount);
 757   }
 758   EXPECT_EQ(1, destructorCount);
 759
 760   destructorCount = 0;
 761   {
 762     std::unique_ptr<OwnershipTestClass[]> p(new OwnershipTestClass[2]);
 763     std::unique_ptr<IOBuf> buf(IOBuf::takeOwnership(std::move(p), 2));
 764     EXPECT_EQ(2 * sizeof(OwnershipTestClass), buf->length());
 765     EXPECT_EQ(0, destructorCount);
 766   }
 767   EXPECT_EQ(2, destructorCount);
 768
 769   customDeleterCount = 0;
 770   destructorCount = 0;
 771   {
 772     std::unique_ptr<OwnershipTestClass, CustomDeleter>
 773       p(new OwnershipTestClass(), customDelete);
 774     std::unique_ptr<IOBuf> buf(IOBuf::takeOwnership(std::move(p)));
 775     EXPECT_EQ(sizeof(OwnershipTestClass), buf->length());
 776     EXPECT_EQ(0, destructorCount);
 777   }
 778   EXPECT_EQ(1, destructorCount);
 779   EXPECT_EQ(1, customDeleterCount);
 780
 781   customDeleterCount = 0;
 782   destructorCount = 0;
 783   {
 784     std::unique_ptr<OwnershipTestClass[], CustomDeleter>
 785       p(new OwnershipTestClass[2], CustomDeleter(customDeleteArray));
 786     std::unique_ptr<IOBuf> buf(IOBuf::takeOwnership(std::move(p), 2));
 787     EXPECT_EQ(2 * sizeof(OwnershipTestClass), buf->length());
 788     EXPECT_EQ(0, destructorCount);
 789   }
 790   EXPECT_EQ(2, destructorCount);
 791   EXPECT_EQ(1, customDeleterCount);
 792 }
 793
 794 TEST(IOBuf, Alignment) {
 795   size_t alignment = alignof(std::max_align_t);
 796
 797   std::vector<size_t> sizes {0, 1, 64, 256, 1024, 1 << 10};
 798   for (size_t size : sizes) {
 799     auto buf = IOBuf::create(size);
 800     uintptr_t p = reinterpret_cast<uintptr_t>(buf->data());
 801     EXPECT_EQ(0, p & (alignment - 1)) << "size=" << size;
 802   }
 803 }
 804
 805 TEST(TypedIOBuf, Simple) {
 806   auto buf = IOBuf::create(0);
 807   TypedIOBuf<uint64_t> typed(buf.get());
 808   const uint64_t n = 10000;
 809   typed.reserve(0, n);
 810   EXPECT_LE(n, typed.capacity());
 811   for (uint64_t i = 0; i < n; i++) {
 812     *typed.writableTail() = i;
 813     typed.append(1);
 814   }
 815   EXPECT_EQ(n, typed.length());
 816   for (uint64_t i = 0; i < n; i++) {
 817     EXPECT_EQ(i, typed.data()[i]);
 818   }
 819 }
 820 enum BufType {
 821   CREATE,
 822   TAKE_OWNERSHIP_MALLOC,
 823   TAKE_OWNERSHIP_CUSTOM,
 824   USER_OWNED,
 825 };
 826
 827 // chain element size, number of elements in chain, shared
 828 class MoveToFbStringTest
 829   : public ::testing::TestWithParam<std::tr1::tuple<int, int, bool, BufType>> {
 830  protected:
 831   void SetUp() override {
 832     elementSize_ = std::tr1::get<0>(GetParam());
 833     elementCount_ = std::tr1::get<1>(GetParam());
 834     shared_ = std::tr1::get<2>(GetParam());
 835     type_ = std::tr1::get<3>(GetParam());
 836
 837     buf_ = makeBuf();
 838     for (int i = 0; i < elementCount_ - 1; ++i) {
 839       buf_->prependChain(makeBuf());
 840     }
 841     EXPECT_EQ(elementCount_, buf_->countChainElements());
 842     EXPECT_EQ(elementCount_ * elementSize_, buf_->computeChainDataLength());
 843     if (shared_) {
 844       buf2_ = buf_->clone();
 845       EXPECT_EQ(elementCount_, buf2_->countChainElements());
 846       EXPECT_EQ(elementCount_ * elementSize_, buf2_->computeChainDataLength());
 847     }
 848   }
 849
 850   std::unique_ptr<IOBuf> makeBuf() {
 851     unique_ptr<IOBuf> buf;
 852     switch (type_) {
 853       case CREATE:
 854         buf = IOBuf::create(elementSize_);
 855         buf->append(elementSize_);
 856         break;
 857       case TAKE_OWNERSHIP_MALLOC: {
 858         void* data = malloc(elementSize_);
 859         if (!data) {
 860           throw std::bad_alloc();
 861         }
 862         buf = IOBuf::takeOwnership(data, elementSize_);
 863         break;
 864       }
 865       case TAKE_OWNERSHIP_CUSTOM: {
 866         uint8_t* data = new uint8_t[elementSize_];
 867         buf = IOBuf::takeOwnership(data, elementSize_, testFreeFn);
 868         break;
 869       }
 870       case USER_OWNED: {
 871         unique_ptr<uint8_t[]> data(new uint8_t[elementSize_]);
 872         buf = IOBuf::wrapBuffer(data.get(), elementSize_);
 873         ownedBuffers_.emplace_back(std::move(data));
 874         break;
 875       }
 876       default:
 877         throw std::invalid_argument("unexpected buffer type parameter");
 878         break;
 879     }
 880     memset(buf->writableData(), 'x', elementSize_);
 881     return buf;
 882   }
 883
 884   void check(std::unique_ptr<IOBuf>& buf) {
 885     fbstring str = buf->moveToFbString();
 886     EXPECT_EQ(elementCount_ * elementSize_, str.size());
 887     EXPECT_EQ(elementCount_ * elementSize_, strspn(str.c_str(), "x"));
 888     EXPECT_EQ(0, buf->length());
 889     EXPECT_EQ(1, buf->countChainElements());
 890     EXPECT_EQ(0, buf->computeChainDataLength());
 891     EXPECT_FALSE(buf->isChained());
 892   }
 893
 894   int elementSize_;
 895   int elementCount_;
 896   bool shared_;
 897   BufType type_;
 898   std::unique_ptr<IOBuf> buf_;
 899   std::unique_ptr<IOBuf> buf2_;
 900   std::vector<std::unique_ptr<uint8_t[]>> ownedBuffers_;
 901 };
 902
 903 TEST_P(MoveToFbStringTest, Simple) {
 904   check(buf_);
 905   if (shared_) {
 906     check(buf2_);
 907   }
 908 }
 909
 910 INSTANTIATE_TEST_CASE_P(
 911     MoveToFbString,
 912     MoveToFbStringTest,
 913     ::testing::Combine(
 914         ::testing::Values(0, 1, 24, 256, 1 << 10, 1 << 20),  // element size
 915         ::testing::Values(1, 2, 10),                         // element count
 916         ::testing::Bool(),                                   // shared
 917         ::testing::Values(CREATE, TAKE_OWNERSHIP_MALLOC,
 918                           TAKE_OWNERSHIP_CUSTOM, USER_OWNED)));
 919
 920 TEST(IOBuf, getIov) {
 921   uint32_t fillSeed = 0xdeadbeef;
 922   boost::mt19937 gen(fillSeed);
 923
 924   size_t len = 4096;
 925   size_t count = 32;
 926   auto buf = IOBuf::create(len + 1);
 927   buf->append(rand() % len + 1);
 928   fillBuf(buf.get(), gen);
 929
 930   for (size_t i = 0; i < count - 1; i++) {
 931     auto buf2 = IOBuf::create(len + 1);
 932     buf2->append(rand() % len + 1);
 933     fillBuf(buf2.get(), gen);
 934     buf->prependChain(std::move(buf2));
 935   }
 936   EXPECT_EQ(count, buf->countChainElements());
 937
 938   auto iov = buf->getIov();
 939   EXPECT_EQ(count, iov.size());
 940
 941   IOBuf const* p = buf.get();
 942   for (size_t i = 0; i < count; i++, p = p->next()) {
 943     EXPECT_EQ(p->data(), iov[i].iov_base);
 944     EXPECT_EQ(p->length(), iov[i].iov_len);
 945   }
 946
 947   // an empty buf should be skipped in the iov.
 948   buf->next()->clear();
 949   iov = buf->getIov();
 950   EXPECT_EQ(count - 1, iov.size());
 951   EXPECT_EQ(buf->next()->next()->data(), iov[1].iov_base);
 952
 953   // same for the first one being empty
 954   buf->clear();
 955   iov = buf->getIov();
 956   EXPECT_EQ(count - 2, iov.size());
 957   EXPECT_EQ(buf->next()->next()->data(), iov[0].iov_base);
 958
 959   // and the last one
 960   buf->prev()->clear();
 961   iov = buf->getIov();
 962   EXPECT_EQ(count - 3, iov.size());
 963
 964   // test appending to an existing iovec array
 965   iov.clear();
 966   const char localBuf[] = "hello";
 967   iov.push_back({(void*)localBuf, sizeof(localBuf)});
 968   iov.push_back({(void*)localBuf, sizeof(localBuf)});
 969   buf->appendToIov(&iov);
 970   EXPECT_EQ(count - 1, iov.size());
 971   EXPECT_EQ(localBuf, iov[0].iov_base);
 972   EXPECT_EQ(localBuf, iov[1].iov_base);
 973   // The first two IOBufs were cleared, so the next iov entry
 974   // should be the third IOBuf in the chain.
 975   EXPECT_EQ(buf->next()->next()->data(), iov[2].iov_base);
 976 }
 977
 978 TEST(IOBuf, move) {
 979   // Default allocate an IOBuf on the stack
 980   IOBuf outerBuf;
 981   char data[] = "foobar";
 982   uint32_t length = sizeof(data);
 983   uint32_t actualCapacity{0};
 984   const void* ptr{nullptr};
 985
 986   {
 987     // Create a small IOBuf on the stack.
 988     // Note that IOBufs created on the stack always use an external buffer.
 989     IOBuf b1(IOBuf::CREATE, 10);
 990     actualCapacity = b1.capacity();
 991     EXPECT_GE(actualCapacity, 10);
 992     EXPECT_EQ(0, b1.length());
 993     EXPECT_FALSE(b1.isShared());
 994     ptr = b1.data();
 995     ASSERT_TRUE(ptr != nullptr);
 996     memcpy(b1.writableTail(), data, length);
 997     b1.append(length);
 998     EXPECT_EQ(length, b1.length());
 999
1000     // Use the move constructor
1001     IOBuf b2(std::move(b1));
1002     EXPECT_EQ(ptr, b2.data());
1003     EXPECT_EQ(length, b2.length());
1004     EXPECT_EQ(actualCapacity, b2.capacity());
1005     EXPECT_FALSE(b2.isShared());
1006
1007     // Use the move assignment operator
1008     outerBuf = std::move(b2);
1009     // Close scope, destroying b1 and b2
1010     // (which are both be invalid now anyway after moving out of them)
1011   }
1012
1013   EXPECT_EQ(ptr, outerBuf.data());
1014   EXPECT_EQ(length, outerBuf.length());
1015   EXPECT_EQ(actualCapacity, outerBuf.capacity());
1016   EXPECT_FALSE(outerBuf.isShared());
1017 }
1018
1019 namespace {
1020 std::unique_ptr<IOBuf> fromStr(StringPiece sp) {
1021   return IOBuf::copyBuffer(ByteRange(sp));
1022 }
1023 }  // namespace
1024
1025 TEST(IOBuf, HashAndEqual) {
1026   folly::IOBufEqual eq;
1027   folly::IOBufHash hash;
1028
1029   EXPECT_TRUE(eq(nullptr, nullptr));
1030   EXPECT_EQ(0, hash(nullptr));
1031
1032   auto empty = IOBuf::create(0);
1033
1034   EXPECT_TRUE(eq(*empty, *empty));
1035   EXPECT_TRUE(eq(empty, empty));
1036
1037   EXPECT_FALSE(eq(nullptr, empty));
1038   EXPECT_FALSE(eq(empty, nullptr));
1039
1040   EXPECT_EQ(hash(*empty), hash(empty));
1041   EXPECT_NE(0, hash(empty));
1042
1043   auto a = fromStr("hello");
1044
1045   EXPECT_TRUE(eq(*a, *a));
1046   EXPECT_TRUE(eq(a, a));
1047
1048   EXPECT_FALSE(eq(nullptr, a));
1049   EXPECT_FALSE(eq(a, nullptr));
1050
1051   EXPECT_EQ(hash(*a), hash(a));
1052   EXPECT_NE(0, hash(a));
1053
1054   auto b = fromStr("hello");
1055
1056   EXPECT_TRUE(eq(*a, *b));
1057   EXPECT_TRUE(eq(a, b));
1058
1059   EXPECT_EQ(hash(a), hash(b));
1060
1061   auto c = fromStr("hellow");
1062
1063   EXPECT_FALSE(eq(a, c));
1064   EXPECT_NE(hash(a), hash(c));
1065
1066   auto d = fromStr("world");
1067
1068   EXPECT_FALSE(eq(a, d));
1069   EXPECT_NE(hash(a), hash(d));
1070
1071   auto e = fromStr("helloworld");
1072   auto f = fromStr("hello");
1073   f->prependChain(fromStr("wo"));
1074   f->prependChain(fromStr("rld"));
1075
1076   EXPECT_TRUE(eq(e, f));
1077   EXPECT_EQ(hash(e), hash(f));
1078 }
1079
1080 // reserveSlow() had a bug when reallocating the buffer in place. It would
1081 // preserve old headroom if it's not too much (heuristically) but wouldn't
1082 // adjust the requested amount of memory to account for that; the end result
1083 // would be that reserve() would return with less tailroom than requested.
1084 TEST(IOBuf, ReserveWithHeadroom) {
1085   // This is assuming jemalloc, where we know that 4096 and 8192 bytes are
1086   // valid (and consecutive) allocation sizes. We're hoping that our
1087   // 4096-byte buffer can be expanded in place to 8192 (in practice, this
1088   // usually happens).
1089   const char data[] = "Lorem ipsum dolor sit amet, consectetur adipiscing elit";
1090   constexpr size_t reservedSize = 24;  // sizeof(SharedInfo)
1091   // chosen carefully so that the buffer is exactly 4096 bytes
1092   IOBuf buf(IOBuf::CREATE, 4096 - reservedSize);
1093   buf.advance(10);
1094   memcpy(buf.writableData(), data, sizeof(data));
1095   buf.append(sizeof(data));
1096   EXPECT_EQ(sizeof(data), buf.length());
1097
1098   // Grow the buffer (hopefully in place); this would incorrectly reserve
1099   // the 10 bytes of headroom, giving us 10 bytes less than requested.
1100   size_t tailroom = 8192 - reservedSize - sizeof(data);
1101   buf.reserve(0, tailroom);
1102   EXPECT_LE(tailroom, buf.tailroom());
1103   EXPECT_EQ(sizeof(data), buf.length());
1104   EXPECT_EQ(0, memcmp(data, buf.data(), sizeof(data)));
1105 }
1106
1107 TEST(IOBuf, CopyConstructorAndAssignmentOperator) {
1108   auto buf = IOBuf::create(4096);
1109   append(buf, "hello world");
1110   auto buf2 = IOBuf::create(4096);
1111   append(buf2, " goodbye");
1112   buf->prependChain(std::move(buf2));
1113   EXPECT_FALSE(buf->isShared());
1114
1115   {
1116     auto copy = *buf;
1117     EXPECT_TRUE(buf->isShared());
1118     EXPECT_TRUE(copy.isShared());
1119     EXPECT_EQ((void*)buf->data(), (void*)copy.data());
1120     EXPECT_NE(buf->next(), copy.next());  // actually different buffers
1121
1122     auto copy2 = *buf;
1123     copy2.coalesce();
1124     EXPECT_TRUE(buf->isShared());
1125     EXPECT_TRUE(copy.isShared());
1126     EXPECT_FALSE(copy2.isShared());
1127
1128     auto p = reinterpret_cast<const char*>(copy2.data());
1129     EXPECT_EQ("hello world goodbye", std::string(p, copy2.length()));
1130   }
1131
1132   EXPECT_FALSE(buf->isShared());
1133
1134   {
1135     folly::IOBuf newBuf(folly::IOBuf::CREATE, 4096);
1136     EXPECT_FALSE(newBuf.isShared());
1137
1138     auto newBufCopy = newBuf;
1139     EXPECT_TRUE(newBuf.isShared());
1140     EXPECT_TRUE(newBufCopy.isShared());
1141
1142     newBufCopy = *buf;
1143     EXPECT_TRUE(buf->isShared());
1144     EXPECT_FALSE(newBuf.isShared());
1145     EXPECT_TRUE(newBufCopy.isShared());
1146   }
1147
1148   EXPECT_FALSE(buf->isShared());
1149 }
1150
1151 TEST(IOBuf, CloneAsValue) {
1152   auto buf = IOBuf::create(4096);
1153   append(buf, "hello world");
1154   {
1155     auto buf2 = IOBuf::create(4096);
1156     append(buf2, " goodbye");
1157     buf->prependChain(std::move(buf2));
1158     EXPECT_FALSE(buf->isShared());
1159   }
1160
1161   {
1162     auto copy = buf->cloneOneAsValue();
1163     EXPECT_TRUE(buf->isShared());
1164     EXPECT_TRUE(copy.isShared());
1165     EXPECT_EQ((void*)buf->data(), (void*)copy.data());
1166     EXPECT_TRUE(buf->isChained());
1167     EXPECT_FALSE(copy.isChained());
1168
1169     auto copy2 = buf->cloneAsValue();
1170     EXPECT_TRUE(buf->isShared());
1171     EXPECT_TRUE(copy.isShared());
1172     EXPECT_TRUE(copy2.isShared());
1173     EXPECT_TRUE(buf->isChained());
1174     EXPECT_TRUE(copy2.isChained());
1175
1176     copy.unshareOne();
1177     EXPECT_TRUE(buf->isShared());
1178     EXPECT_FALSE(copy.isShared());
1179     EXPECT_NE((void*)buf->data(), (void*)copy.data());
1180     EXPECT_TRUE(copy2.isShared());
1181
1182     auto p = reinterpret_cast<const char*>(copy.data());
1183     EXPECT_EQ("hello world", std::string(p, copy.length()));
1184
1185     copy2.coalesce();
1186     EXPECT_FALSE(buf->isShared());
1187     EXPECT_FALSE(copy.isShared());
1188     EXPECT_FALSE(copy2.isShared());
1189     EXPECT_FALSE(copy2.isChained());
1190
1191     auto p2 = reinterpret_cast<const char*>(copy2.data());
1192     EXPECT_EQ("hello world goodbye", std::string(p2, copy2.length()));
1193   }
1194
1195   EXPECT_FALSE(buf->isShared());
1196 }
1197
1198 namespace {
1199 // Use with string literals only
1200 std::unique_ptr<IOBuf> wrap(const char* str) {
1201   return IOBuf::wrapBuffer(str, strlen(str));
1202 }
1203
1204 std::unique_ptr<IOBuf> copy(const char* str) {
1205   // At least 1KiB of tailroom, to ensure an external buffer
1206   return IOBuf::copyBuffer(str, strlen(str), 0, 1024);
1207 }
1208
1209 std::string toString(const folly::IOBuf& buf) {
1210   std::string result;
1211   result.reserve(buf.computeChainDataLength());
1212   for (auto& b : buf) {
1213     result.append(reinterpret_cast<const char*>(b.data()), b.size());
1214   }
1215   return result;
1216 }
1217
1218 char* writableStr(folly::IOBuf& buf) {
1219   return reinterpret_cast<char*>(buf.writableData());
1220 }
1221
1222 }  // namespace
1223
1224 TEST(IOBuf, Managed) {
1225   auto hello = "hello";
1226   auto buf1UP = wrap(hello);
1227   auto buf1 = buf1UP.get();
1228   EXPECT_FALSE(buf1->isManagedOne());
1229   auto buf2UP = copy("world");
1230   auto buf2 = buf2UP.get();
1231   EXPECT_TRUE(buf2->isManagedOne());
1232   auto buf3UP = wrap(hello);
1233   auto buf3 = buf3UP.get();
1234   auto buf4UP = buf2->clone();
1235   auto buf4 = buf4UP.get();
1236
1237   // buf1 and buf3 share the same memory (but are unmanaged)
1238   EXPECT_FALSE(buf1->isManagedOne());
1239   EXPECT_FALSE(buf3->isManagedOne());
1240   EXPECT_TRUE(buf1->isSharedOne());
1241   EXPECT_TRUE(buf3->isSharedOne());
1242   EXPECT_EQ(buf1->data(), buf3->data());
1243
1244   // buf2 and buf4 share the same memory (but are managed)
1245   EXPECT_TRUE(buf2->isManagedOne());
1246   EXPECT_TRUE(buf4->isManagedOne());
1247   EXPECT_TRUE(buf2->isSharedOne());
1248   EXPECT_TRUE(buf4->isSharedOne());
1249   EXPECT_EQ(buf2->data(), buf4->data());
1250
1251   buf1->prependChain(std::move(buf2UP));
1252   buf1->prependChain(std::move(buf3UP));
1253   buf1->prependChain(std::move(buf4UP));
1254
1255   EXPECT_EQ("helloworldhelloworld", toString(*buf1));
1256   EXPECT_FALSE(buf1->isManaged());
1257
1258   buf1->makeManaged();
1259   EXPECT_TRUE(buf1->isManaged());
1260
1261   // buf1 and buf3 are now unshared (because they were unmanaged)
1262   EXPECT_TRUE(buf1->isManagedOne());
1263   EXPECT_TRUE(buf3->isManagedOne());
1264   EXPECT_FALSE(buf1->isSharedOne());
1265   EXPECT_FALSE(buf3->isSharedOne());
1266   EXPECT_NE(buf1->data(), buf3->data());
1267
1268   // buf2 and buf4 are still shared
1269   EXPECT_TRUE(buf2->isManagedOne());
1270   EXPECT_TRUE(buf4->isManagedOne());
1271   EXPECT_TRUE(buf2->isSharedOne());
1272   EXPECT_TRUE(buf4->isSharedOne());
1273   EXPECT_EQ(buf2->data(), buf4->data());
1274
1275   // And verify that the truth is what we expect: modify a byte in buf1 and
1276   // buf2, see that the change from buf1 is *not* reflected in buf3, but the
1277   // change from buf2 is reflected in buf4.
1278   writableStr(*buf1)[0] = 'j';
1279   writableStr(*buf2)[0] = 'x';
1280   EXPECT_EQ("jelloxorldhelloxorld", toString(*buf1));
1281 }