folly/io/test/IOBufTest.cpp

   1 /*
   2  * Copyright 2017 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
  24 #include <folly/Malloc.h>
  25 #include <folly/Range.h>
  26 #include <folly/portability/GTest.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   const uint32_t size4 = 2345;
 191   unique_ptr<uint8_t[]> buf4(new uint8_t[size4]);
 192   IOBuf iobuf4 = IOBuf::wrapBufferAsValue(buf4.get(), size4);
 193   EXPECT_EQ(buf4.get(), iobuf4.data());
 194   EXPECT_EQ(size4, iobuf4.length());
 195   EXPECT_EQ(buf4.get(), iobuf4.buffer());
 196   EXPECT_EQ(size4, iobuf4.capacity());
 197 }
 198
 199 TEST(IOBuf, CreateCombined) {
 200   // Create a combined IOBuf, then destroy it.
 201   // The data buffer and IOBuf both become unused as part of the destruction
 202   {
 203     auto buf = IOBuf::createCombined(256);
 204     EXPECT_FALSE(buf->isShared());
 205   }
 206
 207   // Create a combined IOBuf, clone from it, and then destroy the original
 208   // IOBuf.  The data buffer cannot be deleted until the clone is also
 209   // destroyed.
 210   {
 211     auto bufA = IOBuf::createCombined(256);
 212     EXPECT_FALSE(bufA->isShared());
 213     auto bufB = bufA->clone();
 214     EXPECT_TRUE(bufA->isShared());
 215     EXPECT_TRUE(bufB->isShared());
 216     bufA.reset();
 217     EXPECT_FALSE(bufB->isShared());
 218   }
 219
 220   // Create a combined IOBuf, then call reserve() to get a larger buffer.
 221   // The IOBuf no longer points to the combined data buffer, but the
 222   // overall memory segment cannot be deleted until the IOBuf is also
 223   // destroyed.
 224   {
 225     auto buf = IOBuf::createCombined(256);
 226     buf->reserve(0, buf->capacity() + 100);
 227   }
 228
 229   // Create a combined IOBuf, clone from it, then call unshare() on the original
 230   // buffer.  This creates a situation where bufB is pointing at the combined
 231   // buffer associated with bufA, but bufA is now using a different buffer.
 232   auto testSwap = [](bool resetAFirst) {
 233     auto bufA = IOBuf::createCombined(256);
 234     EXPECT_FALSE(bufA->isShared());
 235     auto bufB = bufA->clone();
 236     EXPECT_TRUE(bufA->isShared());
 237     EXPECT_TRUE(bufB->isShared());
 238     bufA->unshare();
 239     EXPECT_FALSE(bufA->isShared());
 240     EXPECT_FALSE(bufB->isShared());
 241
 242     if (resetAFirst) {
 243       bufA.reset();
 244       bufB.reset();
 245     } else {
 246       bufB.reset();
 247       bufA.reset();
 248     }
 249   };
 250   testSwap(true);
 251   testSwap(false);
 252 }
 253
 254 void fillBuf(uint8_t* buf, uint32_t length, boost::mt19937& gen) {
 255   for (uint32_t n = 0; n < length; ++n) {
 256     buf[n] = static_cast<uint8_t>(gen() & 0xff);
 257   }
 258 }
 259
 260 void fillBuf(IOBuf* buf, boost::mt19937& gen) {
 261   buf->unshare();
 262   fillBuf(buf->writableData(), buf->length(), gen);
 263 }
 264
 265 void checkBuf(const uint8_t* buf, uint32_t length, boost::mt19937& gen) {
 266   // Rather than using EXPECT_EQ() to check each character,
 267   // count the number of differences and the first character that differs.
 268   // This way on error we'll report just that information, rather than tons of
 269   // failed checks for each byte in the buffer.
 270   uint32_t numDifferences = 0;
 271   uint32_t firstDiffIndex = 0;
 272   uint8_t firstDiffExpected = 0;
 273   for (uint32_t n = 0; n < length; ++n) {
 274     uint8_t expected = static_cast<uint8_t>(gen() & 0xff);
 275     if (buf[n] == expected) {
 276       continue;
 277     }
 278
 279     if (numDifferences == 0) {
 280       firstDiffIndex = n;
 281       firstDiffExpected = expected;
 282     }
 283     ++numDifferences;
 284   }
 285
 286   EXPECT_EQ(0, numDifferences);
 287   if (numDifferences > 0) {
 288     // Cast to int so it will be printed numerically
 289     // rather than as a char if the check fails
 290     EXPECT_EQ(static_cast<int>(buf[firstDiffIndex]),
 291               static_cast<int>(firstDiffExpected));
 292   }
 293 }
 294
 295 void checkBuf(IOBuf* buf, boost::mt19937& gen) {
 296   checkBuf(buf->data(), buf->length(), gen);
 297 }
 298
 299 void checkBuf(ByteRange buf, boost::mt19937& gen) {
 300   checkBuf(buf.data(), buf.size(), gen);
 301 }
 302
 303 void checkChain(IOBuf* buf, boost::mt19937& gen) {
 304   IOBuf *current = buf;
 305   do {
 306     checkBuf(current->data(), current->length(), gen);
 307     current = current->next();
 308   } while (current != buf);
 309 }
 310
 311 TEST(IOBuf, Chaining) {
 312   uint32_t fillSeed = 0x12345678;
 313   boost::mt19937 gen(fillSeed);
 314
 315   // An IOBuf with external storage
 316   uint32_t headroom = 123;
 317   unique_ptr<IOBuf> iob1(IOBuf::create(2048));
 318   iob1->advance(headroom);
 319   iob1->append(1500);
 320   fillBuf(iob1.get(), gen);
 321
 322   // An IOBuf with internal storage
 323   unique_ptr<IOBuf> iob2(IOBuf::create(20));
 324   iob2->append(20);
 325   fillBuf(iob2.get(), gen);
 326
 327   // An IOBuf around a buffer it doesn't own
 328   uint8_t localbuf[1234];
 329   fillBuf(localbuf, 1234, gen);
 330   unique_ptr<IOBuf> iob3(IOBuf::wrapBuffer(localbuf, sizeof(localbuf)));
 331
 332   // An IOBuf taking ownership of a user-supplied buffer
 333   uint32_t heapBufSize = 900;
 334   uint8_t* heapBuf = static_cast<uint8_t*>(malloc(heapBufSize));
 335   fillBuf(heapBuf, heapBufSize, gen);
 336   unique_ptr<IOBuf> iob4(IOBuf::takeOwnership(heapBuf, heapBufSize));
 337
 338   // An IOBuf taking ownership of a user-supplied buffer with
 339   // a custom free function
 340   uint32_t arrayBufSize = 321;
 341   uint8_t* arrayBuf = new uint8_t[arrayBufSize];
 342   fillBuf(arrayBuf, arrayBufSize, gen);
 343   uint32_t arrayBufFreeCount = 0;
 344   unique_ptr<IOBuf> iob5(IOBuf::takeOwnership(arrayBuf, arrayBufSize,
 345                                               deleteArrayBuffer,
 346                                               &arrayBufFreeCount));
 347
 348   EXPECT_FALSE(iob1->isChained());
 349   EXPECT_FALSE(iob2->isChained());
 350   EXPECT_FALSE(iob3->isChained());
 351   EXPECT_FALSE(iob4->isChained());
 352   EXPECT_FALSE(iob5->isChained());
 353
 354   EXPECT_FALSE(iob1->isSharedOne());
 355   EXPECT_FALSE(iob2->isSharedOne());
 356   EXPECT_TRUE(iob3->isSharedOne()); // since we own the buffer
 357   EXPECT_FALSE(iob4->isSharedOne());
 358   EXPECT_FALSE(iob5->isSharedOne());
 359
 360   // Chain the buffers all together
 361   // Since we are going to relinquish ownership of iob2-5 to the chain,
 362   // store raw pointers to them so we can reference them later.
 363   IOBuf* iob2ptr = iob2.get();
 364   IOBuf* iob3ptr = iob3.get();
 365   IOBuf* iob4ptr = iob4.get();
 366   IOBuf* iob5ptr = iob5.get();
 367
 368   iob1->prependChain(std::move(iob2));
 369   iob1->prependChain(std::move(iob4));
 370   iob2ptr->appendChain(std::move(iob3));
 371   iob1->prependChain(std::move(iob5));
 372
 373   EXPECT_EQ(iob2ptr, iob1->next());
 374   EXPECT_EQ(iob3ptr, iob2ptr->next());
 375   EXPECT_EQ(iob4ptr, iob3ptr->next());
 376   EXPECT_EQ(iob5ptr, iob4ptr->next());
 377   EXPECT_EQ(iob1.get(), iob5ptr->next());
 378
 379   EXPECT_EQ(iob5ptr, iob1->prev());
 380   EXPECT_EQ(iob1.get(), iob2ptr->prev());
 381   EXPECT_EQ(iob2ptr, iob3ptr->prev());
 382   EXPECT_EQ(iob3ptr, iob4ptr->prev());
 383   EXPECT_EQ(iob4ptr, iob5ptr->prev());
 384
 385   EXPECT_TRUE(iob1->isChained());
 386   EXPECT_TRUE(iob2ptr->isChained());
 387   EXPECT_TRUE(iob3ptr->isChained());
 388   EXPECT_TRUE(iob4ptr->isChained());
 389   EXPECT_TRUE(iob5ptr->isChained());
 390
 391   uint64_t fullLength = (iob1->length() + iob2ptr->length() +
 392                          iob3ptr->length() + iob4ptr->length() +
 393                         iob5ptr->length());
 394   EXPECT_EQ(5, iob1->countChainElements());
 395   EXPECT_EQ(fullLength, iob1->computeChainDataLength());
 396
 397   // Since iob3 is shared, the entire buffer should report itself as shared
 398   EXPECT_TRUE(iob1->isShared());
 399   // Unshare just iob3
 400   iob3ptr->unshareOne();
 401   EXPECT_FALSE(iob3ptr->isSharedOne());
 402   // Now everything in the chain should be unshared.
 403   // Check on all members of the chain just for good measure
 404   EXPECT_FALSE(iob1->isShared());
 405   EXPECT_FALSE(iob2ptr->isShared());
 406   EXPECT_FALSE(iob3ptr->isShared());
 407   EXPECT_FALSE(iob4ptr->isShared());
 408   EXPECT_FALSE(iob5ptr->isShared());
 409
 410   // Check iteration
 411   gen.seed(fillSeed);
 412   size_t count = 0;
 413   for (auto buf : *iob1) {
 414     checkBuf(buf, gen);
 415     ++count;
 416   }
 417   EXPECT_EQ(5, count);
 418
 419   // Clone one of the IOBufs in the chain
 420   unique_ptr<IOBuf> iob4clone = iob4ptr->cloneOne();
 421   gen.seed(fillSeed);
 422   checkBuf(iob1.get(), gen);
 423   checkBuf(iob2ptr, gen);
 424   checkBuf(iob3ptr, gen);
 425   checkBuf(iob4clone.get(), gen);
 426   checkBuf(iob5ptr, gen);
 427
 428   EXPECT_TRUE(iob1->isShared());
 429   EXPECT_TRUE(iob2ptr->isShared());
 430   EXPECT_TRUE(iob3ptr->isShared());
 431   EXPECT_TRUE(iob4ptr->isShared());
 432   EXPECT_TRUE(iob5ptr->isShared());
 433
 434   EXPECT_FALSE(iob1->isSharedOne());
 435   EXPECT_FALSE(iob2ptr->isSharedOne());
 436   EXPECT_FALSE(iob3ptr->isSharedOne());
 437   EXPECT_TRUE(iob4ptr->isSharedOne());
 438   EXPECT_FALSE(iob5ptr->isSharedOne());
 439
 440   // Unshare that clone
 441   EXPECT_TRUE(iob4clone->isSharedOne());
 442   iob4clone->unshare();
 443   EXPECT_FALSE(iob4clone->isSharedOne());
 444   EXPECT_FALSE(iob4ptr->isSharedOne());
 445   EXPECT_FALSE(iob1->isShared());
 446   iob4clone.reset();
 447
 448
 449   // Create a clone of a different IOBuf
 450   EXPECT_FALSE(iob1->isShared());
 451   EXPECT_FALSE(iob3ptr->isSharedOne());
 452
 453   unique_ptr<IOBuf> iob3clone = iob3ptr->cloneOne();
 454   gen.seed(fillSeed);
 455   checkBuf(iob1.get(), gen);
 456   checkBuf(iob2ptr, gen);
 457   checkBuf(iob3clone.get(), gen);
 458   checkBuf(iob4ptr, gen);
 459   checkBuf(iob5ptr, gen);
 460
 461   EXPECT_TRUE(iob1->isShared());
 462   EXPECT_TRUE(iob3ptr->isSharedOne());
 463   EXPECT_FALSE(iob1->isSharedOne());
 464
 465   // Delete the clone and make sure the original is unshared
 466   iob3clone.reset();
 467   EXPECT_FALSE(iob1->isShared());
 468   EXPECT_FALSE(iob3ptr->isSharedOne());
 469
 470
 471   // Clone the entire chain
 472   unique_ptr<IOBuf> chainClone = iob1->clone();
 473   // Verify that the data is correct.
 474   EXPECT_EQ(fullLength, chainClone->computeChainDataLength());
 475   gen.seed(fillSeed);
 476   checkChain(chainClone.get(), gen);
 477
 478   // Check that the buffers report sharing correctly
 479   EXPECT_TRUE(chainClone->isShared());
 480   EXPECT_TRUE(iob1->isShared());
 481
 482   EXPECT_TRUE(iob1->isSharedOne());
 483   EXPECT_TRUE(iob2ptr->isSharedOne());
 484   EXPECT_TRUE(iob3ptr->isSharedOne());
 485   EXPECT_TRUE(iob4ptr->isSharedOne());
 486   EXPECT_TRUE(iob5ptr->isSharedOne());
 487
 488   // Unshare the cloned chain
 489   chainClone->unshare();
 490   EXPECT_FALSE(chainClone->isShared());
 491   EXPECT_FALSE(iob1->isShared());
 492
 493   // Make sure the unshared result still has the same data
 494   EXPECT_EQ(fullLength, chainClone->computeChainDataLength());
 495   gen.seed(fillSeed);
 496   checkChain(chainClone.get(), gen);
 497
 498   // Destroy this chain
 499   chainClone.reset();
 500
 501
 502   // Clone a new chain
 503   EXPECT_FALSE(iob1->isShared());
 504   chainClone = iob1->clone();
 505   EXPECT_TRUE(iob1->isShared());
 506   EXPECT_TRUE(chainClone->isShared());
 507
 508   // Delete the original chain
 509   iob1.reset();
 510   EXPECT_FALSE(chainClone->isShared());
 511
 512   // Coalesce the chain
 513   //
 514   // Coalescing this chain will create a new buffer and release the last
 515   // refcount on the original buffers we created.  Also make sure
 516   // that arrayBufFreeCount increases to one to indicate that arrayBuf was
 517   // freed.
 518   EXPECT_EQ(5, chainClone->countChainElements());
 519   EXPECT_EQ(0, arrayBufFreeCount);
 520
 521   // Buffer lengths: 1500 20 1234 900 321
 522   // Attempting to gather more data than available should fail
 523   EXPECT_THROW(chainClone->gather(4000), std::overflow_error);
 524   // Coalesce the first 3 buffers
 525   chainClone->gather(1521);
 526   EXPECT_EQ(3, chainClone->countChainElements());
 527   EXPECT_EQ(0, arrayBufFreeCount);
 528
 529   // Make sure the data is still the same after coalescing
 530   EXPECT_EQ(fullLength, chainClone->computeChainDataLength());
 531   gen.seed(fillSeed);
 532   checkChain(chainClone.get(), gen);
 533
 534   // Coalesce the entire chain
 535   chainClone->coalesce();
 536   EXPECT_EQ(1, chainClone->countChainElements());
 537   EXPECT_EQ(1, arrayBufFreeCount);
 538
 539   // Make sure the data is still the same after coalescing
 540   EXPECT_EQ(fullLength, chainClone->computeChainDataLength());
 541   gen.seed(fillSeed);
 542   checkChain(chainClone.get(), gen);
 543
 544   // Make a new chain to test the unlink and pop operations
 545   iob1 = IOBuf::create(1);
 546   iob1->append(1);
 547   IOBuf *iob1ptr = iob1.get();
 548   iob2 = IOBuf::create(3);
 549   iob2->append(3);
 550   iob2ptr = iob2.get();
 551   iob3 = IOBuf::create(5);
 552   iob3->append(5);
 553   iob3ptr = iob3.get();
 554   iob4 = IOBuf::create(7);
 555   iob4->append(7);
 556   iob4ptr = iob4.get();
 557   iob1->appendChain(std::move(iob2));
 558   iob1->prev()->appendChain(std::move(iob3));
 559   iob1->prev()->appendChain(std::move(iob4));
 560   EXPECT_EQ(4, iob1->countChainElements());
 561   EXPECT_EQ(16, iob1->computeChainDataLength());
 562
 563   // Unlink from the middle of the chain
 564   iob3 = iob3ptr->unlink();
 565   EXPECT_TRUE(iob3.get() == iob3ptr);
 566   EXPECT_EQ(3, iob1->countChainElements());
 567   EXPECT_EQ(11, iob1->computeChainDataLength());
 568
 569   // Unlink from the end of the chain
 570   iob4 = iob1->prev()->unlink();
 571   EXPECT_TRUE(iob4.get() == iob4ptr);
 572   EXPECT_EQ(2, iob1->countChainElements());
 573   EXPECT_TRUE(iob1->next() == iob2ptr);
 574   EXPECT_EQ(4, iob1->computeChainDataLength());
 575
 576   // Pop from the front of the chain
 577   iob2 = iob1->pop();
 578   EXPECT_TRUE(iob1.get() == iob1ptr);
 579   EXPECT_EQ(1, iob1->countChainElements());
 580   EXPECT_EQ(1, iob1->computeChainDataLength());
 581   EXPECT_TRUE(iob2.get() == iob2ptr);
 582   EXPECT_EQ(1, iob2->countChainElements());
 583   EXPECT_EQ(3, iob2->computeChainDataLength());
 584 }
 585
 586 void testFreeFn(void* buffer, void* ptr) {
 587   uint32_t* freeCount = static_cast<uint32_t*>(ptr);;
 588   delete[] static_cast<uint8_t*>(buffer);
 589   if (freeCount) {
 590     ++(*freeCount);
 591   }
 592 };
 593
 594 TEST(IOBuf, Reserve) {
 595   uint32_t fillSeed = 0x23456789;
 596   boost::mt19937 gen(fillSeed);
 597
 598   // Reserve does nothing if empty and doesn't have to grow the buffer
 599   {
 600     gen.seed(fillSeed);
 601     unique_ptr<IOBuf> iob(IOBuf::create(2000));
 602     EXPECT_EQ(0, iob->headroom());
 603     const void* p1 = iob->buffer();
 604     iob->reserve(5, 15);
 605     EXPECT_LE(5, iob->headroom());
 606     EXPECT_EQ(p1, iob->buffer());
 607   }
 608
 609   // Reserve doesn't reallocate if we have enough total room
 610   {
 611     gen.seed(fillSeed);
 612     unique_ptr<IOBuf> iob(IOBuf::create(2000));
 613     iob->append(100);
 614     fillBuf(iob.get(), gen);
 615     EXPECT_EQ(0, iob->headroom());
 616     EXPECT_EQ(100, iob->length());
 617     const void* p1 = iob->buffer();
 618     const uint8_t* d1 = iob->data();
 619     iob->reserve(100, 1800);
 620     EXPECT_LE(100, iob->headroom());
 621     EXPECT_EQ(p1, iob->buffer());
 622     EXPECT_EQ(d1 + 100, iob->data());
 623     gen.seed(fillSeed);
 624     checkBuf(iob.get(), gen);
 625   }
 626
 627   // Reserve reallocates if we don't have enough total room.
 628   // NOTE that, with jemalloc, we know that this won't reallocate in place
 629   // as the size is less than jemallocMinInPlaceExpanadable
 630   {
 631     gen.seed(fillSeed);
 632     unique_ptr<IOBuf> iob(IOBuf::create(2000));
 633     iob->append(100);
 634     fillBuf(iob.get(), gen);
 635     EXPECT_EQ(0, iob->headroom());
 636     EXPECT_EQ(100, iob->length());
 637     const void* p1 = iob->buffer();
 638     iob->reserve(100, 2512);  // allocation sizes are multiples of 256
 639     EXPECT_LE(100, iob->headroom());
 640     if (folly::usingJEMalloc()) {
 641       EXPECT_NE(p1, iob->buffer());
 642     }
 643     gen.seed(fillSeed);
 644     checkBuf(iob.get(), gen);
 645   }
 646
 647   // Test reserve from internal buffer, this used to segfault
 648   {
 649     unique_ptr<IOBuf> iob(IOBuf::create(0));
 650     iob->reserve(0, 2000);
 651     EXPECT_EQ(0, iob->headroom());
 652     EXPECT_LE(2000, iob->tailroom());
 653   }
 654
 655   // Test reserving from a user-allocated buffer.
 656   {
 657     uint8_t* buf = static_cast<uint8_t*>(malloc(100));
 658     auto iob = IOBuf::takeOwnership(buf, 100);
 659     iob->reserve(0, 2000);
 660     EXPECT_EQ(0, iob->headroom());
 661     EXPECT_LE(2000, iob->tailroom());
 662   }
 663
 664   // Test reserving from a user-allocated with a custom free function.
 665   {
 666     uint32_t freeCount{0};
 667     uint8_t* buf = new uint8_t[100];
 668     auto iob = IOBuf::takeOwnership(buf, 100, testFreeFn, &freeCount);
 669     iob->reserve(0, 2000);
 670     EXPECT_EQ(0, iob->headroom());
 671     EXPECT_LE(2000, iob->tailroom());
 672     EXPECT_EQ(1, freeCount);
 673   }
 674 }
 675
 676 TEST(IOBuf, copyBuffer) {
 677   std::string s("hello");
 678   auto buf = IOBuf::copyBuffer(s.data(), s.size(), 1, 2);
 679   EXPECT_EQ(1, buf->headroom());
 680   EXPECT_EQ(s, std::string(reinterpret_cast<const char*>(buf->data()),
 681                            buf->length()));
 682   EXPECT_LE(2, buf->tailroom());
 683
 684   buf = IOBuf::copyBuffer(s, 5, 7);
 685   EXPECT_EQ(5, buf->headroom());
 686   EXPECT_EQ(s, std::string(reinterpret_cast<const char*>(buf->data()),
 687                            buf->length()));
 688   EXPECT_LE(7, buf->tailroom());
 689
 690   std::string empty;
 691   buf = IOBuf::copyBuffer(empty, 3, 6);
 692   EXPECT_EQ(3, buf->headroom());
 693   EXPECT_EQ(0, buf->length());
 694   EXPECT_LE(6, buf->tailroom());
 695
 696   // A stack-allocated version
 697   IOBuf stackBuf(IOBuf::COPY_BUFFER, s, 1, 2);
 698   EXPECT_EQ(1, stackBuf.headroom());
 699   EXPECT_EQ(s, std::string(reinterpret_cast<const char*>(stackBuf.data()),
 700                            stackBuf.length()));
 701   EXPECT_LE(2, stackBuf.tailroom());
 702 }
 703
 704 TEST(IOBuf, maybeCopyBuffer) {
 705   std::string s("this is a test");
 706   auto buf = IOBuf::maybeCopyBuffer(s, 1, 2);
 707   EXPECT_EQ(1, buf->headroom());
 708   EXPECT_EQ(s, std::string(reinterpret_cast<const char*>(buf->data()),
 709                            buf->length()));
 710   EXPECT_LE(2, buf->tailroom());
 711
 712   std::string empty;
 713   buf = IOBuf::maybeCopyBuffer("", 5, 7);
 714   EXPECT_EQ(nullptr, buf.get());
 715
 716   buf = IOBuf::maybeCopyBuffer("");
 717   EXPECT_EQ(nullptr, buf.get());
 718 }
 719
 720 TEST(IOBuf, copyEmptyBuffer) {
 721   auto buf = IOBuf::copyBuffer(nullptr, 0);
 722   EXPECT_EQ(buf->length(), 0);
 723 }
 724
 725 namespace {
 726
 727 int customDeleterCount = 0;
 728 int destructorCount = 0;
 729 struct OwnershipTestClass {
 730   explicit OwnershipTestClass(int v = 0) : val(v) { }
 731   ~OwnershipTestClass() {
 732     ++destructorCount;
 733   }
 734   int val;
 735 };
 736
 737 typedef std::function<void(OwnershipTestClass*)> CustomDeleter;
 738
 739 void customDelete(OwnershipTestClass* p) {
 740   ++customDeleterCount;
 741   delete p;
 742 }
 743
 744 void customDeleteArray(OwnershipTestClass* p) {
 745   ++customDeleterCount;
 746   delete[] p;
 747 }
 748
 749 }  // namespace
 750
 751 TEST(IOBuf, takeOwnershipUniquePtr) {
 752   destructorCount = 0;
 753   {
 754     std::unique_ptr<OwnershipTestClass> p(new OwnershipTestClass());
 755   }
 756   EXPECT_EQ(1, destructorCount);
 757
 758   destructorCount = 0;
 759   {
 760     std::unique_ptr<OwnershipTestClass[]> p(new OwnershipTestClass[2]);
 761   }
 762   EXPECT_EQ(2, destructorCount);
 763
 764   destructorCount = 0;
 765   {
 766     std::unique_ptr<OwnershipTestClass> p(new OwnershipTestClass());
 767     std::unique_ptr<IOBuf> buf(IOBuf::takeOwnership(std::move(p)));
 768     EXPECT_EQ(sizeof(OwnershipTestClass), buf->length());
 769     EXPECT_EQ(0, destructorCount);
 770   }
 771   EXPECT_EQ(1, destructorCount);
 772
 773   destructorCount = 0;
 774   {
 775     std::unique_ptr<OwnershipTestClass[]> p(new OwnershipTestClass[2]);
 776     std::unique_ptr<IOBuf> buf(IOBuf::takeOwnership(std::move(p), 2));
 777     EXPECT_EQ(2 * sizeof(OwnershipTestClass), buf->length());
 778     EXPECT_EQ(0, destructorCount);
 779   }
 780   EXPECT_EQ(2, destructorCount);
 781
 782   customDeleterCount = 0;
 783   destructorCount = 0;
 784   {
 785     std::unique_ptr<OwnershipTestClass, CustomDeleter>
 786       p(new OwnershipTestClass(), customDelete);
 787     std::unique_ptr<IOBuf> buf(IOBuf::takeOwnership(std::move(p)));
 788     EXPECT_EQ(sizeof(OwnershipTestClass), buf->length());
 789     EXPECT_EQ(0, destructorCount);
 790   }
 791   EXPECT_EQ(1, destructorCount);
 792   EXPECT_EQ(1, customDeleterCount);
 793
 794   customDeleterCount = 0;
 795   destructorCount = 0;
 796   {
 797     std::unique_ptr<OwnershipTestClass[], CustomDeleter>
 798       p(new OwnershipTestClass[2], CustomDeleter(customDeleteArray));
 799     std::unique_ptr<IOBuf> buf(IOBuf::takeOwnership(std::move(p), 2));
 800     EXPECT_EQ(2 * sizeof(OwnershipTestClass), buf->length());
 801     EXPECT_EQ(0, destructorCount);
 802   }
 803   EXPECT_EQ(2, destructorCount);
 804   EXPECT_EQ(1, customDeleterCount);
 805 }
 806
 807 TEST(IOBuf, Alignment) {
 808   size_t alignment = alignof(std::max_align_t);
 809
 810   std::vector<size_t> sizes {0, 1, 64, 256, 1024, 1 << 10};
 811   for (size_t size : sizes) {
 812     auto buf = IOBuf::create(size);
 813     uintptr_t p = reinterpret_cast<uintptr_t>(buf->data());
 814     EXPECT_EQ(0, p & (alignment - 1)) << "size=" << size;
 815   }
 816 }
 817
 818 TEST(TypedIOBuf, Simple) {
 819   auto buf = IOBuf::create(0);
 820   TypedIOBuf<uint64_t> typed(buf.get());
 821   const uint64_t n = 10000;
 822   typed.reserve(0, n);
 823   EXPECT_LE(n, typed.capacity());
 824   for (uint64_t i = 0; i < n; i++) {
 825     *typed.writableTail() = i;
 826     typed.append(1);
 827   }
 828   EXPECT_EQ(n, typed.length());
 829   for (uint64_t i = 0; i < n; i++) {
 830     EXPECT_EQ(i, typed.data()[i]);
 831   }
 832 }
 833 enum BufType {
 834   CREATE,
 835   TAKE_OWNERSHIP_MALLOC,
 836   TAKE_OWNERSHIP_CUSTOM,
 837   USER_OWNED,
 838 };
 839
 840 // chain element size, number of elements in chain, shared
 841 class MoveToFbStringTest
 842   : public ::testing::TestWithParam<std::tr1::tuple<int, int, bool, BufType>> {
 843  protected:
 844   void SetUp() override {
 845     elementSize_ = std::tr1::get<0>(GetParam());
 846     elementCount_ = std::tr1::get<1>(GetParam());
 847     shared_ = std::tr1::get<2>(GetParam());
 848     type_ = std::tr1::get<3>(GetParam());
 849
 850     buf_ = makeBuf();
 851     for (int i = 0; i < elementCount_ - 1; ++i) {
 852       buf_->prependChain(makeBuf());
 853     }
 854     EXPECT_EQ(elementCount_, buf_->countChainElements());
 855     EXPECT_EQ(elementCount_ * elementSize_, buf_->computeChainDataLength());
 856     if (shared_) {
 857       buf2_ = buf_->clone();
 858       EXPECT_EQ(elementCount_, buf2_->countChainElements());
 859       EXPECT_EQ(elementCount_ * elementSize_, buf2_->computeChainDataLength());
 860     }
 861   }
 862
 863   std::unique_ptr<IOBuf> makeBuf() {
 864     unique_ptr<IOBuf> buf;
 865     switch (type_) {
 866       case CREATE:
 867         buf = IOBuf::create(elementSize_);
 868         buf->append(elementSize_);
 869         break;
 870       case TAKE_OWNERSHIP_MALLOC: {
 871         void* data = malloc(elementSize_);
 872         if (!data) {
 873           throw std::bad_alloc();
 874         }
 875         buf = IOBuf::takeOwnership(data, elementSize_);
 876         break;
 877       }
 878       case TAKE_OWNERSHIP_CUSTOM: {
 879         uint8_t* data = new uint8_t[elementSize_];
 880         buf = IOBuf::takeOwnership(data, elementSize_, testFreeFn);
 881         break;
 882       }
 883       case USER_OWNED: {
 884         unique_ptr<uint8_t[]> data(new uint8_t[elementSize_]);
 885         buf = IOBuf::wrapBuffer(data.get(), elementSize_);
 886         ownedBuffers_.emplace_back(std::move(data));
 887         break;
 888       }
 889       default:
 890         throw std::invalid_argument("unexpected buffer type parameter");
 891     }
 892     memset(buf->writableData(), 'x', elementSize_);
 893     return buf;
 894   }
 895
 896   void check(std::unique_ptr<IOBuf>& buf) {
 897     fbstring str = buf->moveToFbString();
 898     EXPECT_EQ(elementCount_ * elementSize_, str.size());
 899     EXPECT_EQ(elementCount_ * elementSize_, strspn(str.c_str(), "x"));
 900     EXPECT_EQ(0, buf->length());
 901     EXPECT_EQ(1, buf->countChainElements());
 902     EXPECT_EQ(0, buf->computeChainDataLength());
 903     EXPECT_FALSE(buf->isChained());
 904   }
 905
 906   int elementSize_;
 907   int elementCount_;
 908   bool shared_;
 909   BufType type_;
 910   std::unique_ptr<IOBuf> buf_;
 911   std::unique_ptr<IOBuf> buf2_;
 912   std::vector<std::unique_ptr<uint8_t[]>> ownedBuffers_;
 913 };
 914
 915 TEST_P(MoveToFbStringTest, Simple) {
 916   check(buf_);
 917   if (shared_) {
 918     check(buf2_);
 919   }
 920 }
 921
 922 INSTANTIATE_TEST_CASE_P(
 923     MoveToFbString,
 924     MoveToFbStringTest,
 925     ::testing::Combine(
 926         ::testing::Values(0, 1, 24, 256, 1 << 10, 1 << 20),  // element size
 927         ::testing::Values(1, 2, 10),                         // element count
 928         ::testing::Bool(),                                   // shared
 929         ::testing::Values(CREATE, TAKE_OWNERSHIP_MALLOC,
 930                           TAKE_OWNERSHIP_CUSTOM, USER_OWNED)));
 931
 932 TEST(IOBuf, getIov) {
 933   uint32_t fillSeed = 0xdeadbeef;
 934   boost::mt19937 gen(fillSeed);
 935
 936   size_t len = 4096;
 937   size_t count = 32;
 938   auto buf = IOBuf::create(len + 1);
 939   buf->append(rand() % len + 1);
 940   fillBuf(buf.get(), gen);
 941
 942   for (size_t i = 0; i < count - 1; i++) {
 943     auto buf2 = IOBuf::create(len + 1);
 944     buf2->append(rand() % len + 1);
 945     fillBuf(buf2.get(), gen);
 946     buf->prependChain(std::move(buf2));
 947   }
 948   EXPECT_EQ(count, buf->countChainElements());
 949
 950   auto iov = buf->getIov();
 951   EXPECT_EQ(count, iov.size());
 952
 953   IOBuf const* p = buf.get();
 954   for (size_t i = 0; i < count; i++, p = p->next()) {
 955     EXPECT_EQ(p->data(), iov[i].iov_base);
 956     EXPECT_EQ(p->length(), iov[i].iov_len);
 957   }
 958
 959   // an empty buf should be skipped in the iov.
 960   buf->next()->clear();
 961   iov = buf->getIov();
 962   EXPECT_EQ(count - 1, iov.size());
 963   EXPECT_EQ(buf->next()->next()->data(), iov[1].iov_base);
 964
 965   // same for the first one being empty
 966   buf->clear();
 967   iov = buf->getIov();
 968   EXPECT_EQ(count - 2, iov.size());
 969   EXPECT_EQ(buf->next()->next()->data(), iov[0].iov_base);
 970
 971   // and the last one
 972   buf->prev()->clear();
 973   iov = buf->getIov();
 974   EXPECT_EQ(count - 3, iov.size());
 975
 976   // test appending to an existing iovec array
 977   iov.clear();
 978   const char localBuf[] = "hello";
 979   iov.push_back({(void*)localBuf, sizeof(localBuf)});
 980   iov.push_back({(void*)localBuf, sizeof(localBuf)});
 981   buf->appendToIov(&iov);
 982   EXPECT_EQ(count - 1, iov.size());
 983   EXPECT_EQ(localBuf, iov[0].iov_base);
 984   EXPECT_EQ(localBuf, iov[1].iov_base);
 985   // The first two IOBufs were cleared, so the next iov entry
 986   // should be the third IOBuf in the chain.
 987   EXPECT_EQ(buf->next()->next()->data(), iov[2].iov_base);
 988 }
 989
 990 TEST(IOBuf, move) {
 991   // Default allocate an IOBuf on the stack
 992   IOBuf outerBuf;
 993   char data[] = "foobar";
 994   uint32_t length = sizeof(data);
 995   uint32_t actualCapacity{0};
 996   const void* ptr{nullptr};
 997
 998   {
 999     // Create a small IOBuf on the stack.
1000     // Note that IOBufs created on the stack always use an external buffer.
1001     IOBuf b1(IOBuf::CREATE, 10);
1002     actualCapacity = b1.capacity();
1003     EXPECT_GE(actualCapacity, 10);
1004     EXPECT_EQ(0, b1.length());
1005     EXPECT_FALSE(b1.isShared());
1006     ptr = b1.data();
1007     ASSERT_TRUE(ptr != nullptr);
1008     memcpy(b1.writableTail(), data, length);
1009     b1.append(length);
1010     EXPECT_EQ(length, b1.length());
1011
1012     // Use the move constructor
1013     IOBuf b2(std::move(b1));
1014     EXPECT_EQ(ptr, b2.data());
1015     EXPECT_EQ(length, b2.length());
1016     EXPECT_EQ(actualCapacity, b2.capacity());
1017     EXPECT_FALSE(b2.isShared());
1018
1019     // Use the move assignment operator
1020     outerBuf = std::move(b2);
1021     // Close scope, destroying b1 and b2
1022     // (which are both be invalid now anyway after moving out of them)
1023   }
1024
1025   EXPECT_EQ(ptr, outerBuf.data());
1026   EXPECT_EQ(length, outerBuf.length());
1027   EXPECT_EQ(actualCapacity, outerBuf.capacity());
1028   EXPECT_FALSE(outerBuf.isShared());
1029 }
1030
1031 namespace {
1032 std::unique_ptr<IOBuf> fromStr(StringPiece sp) {
1033   return IOBuf::copyBuffer(ByteRange(sp));
1034 }
1035 }  // namespace
1036
1037 TEST(IOBuf, HashAndEqual) {
1038   folly::IOBufEqual eq;
1039   folly::IOBufHash hash;
1040
1041   EXPECT_TRUE(eq(nullptr, nullptr));
1042   EXPECT_EQ(0, hash(nullptr));
1043
1044   auto empty = IOBuf::create(0);
1045
1046   EXPECT_TRUE(eq(*empty, *empty));
1047   EXPECT_TRUE(eq(empty, empty));
1048
1049   EXPECT_FALSE(eq(nullptr, empty));
1050   EXPECT_FALSE(eq(empty, nullptr));
1051
1052   EXPECT_EQ(hash(*empty), hash(empty));
1053   EXPECT_NE(0, hash(empty));
1054
1055   auto a = fromStr("hello");
1056
1057   EXPECT_TRUE(eq(*a, *a));
1058   EXPECT_TRUE(eq(a, a));
1059
1060   EXPECT_FALSE(eq(nullptr, a));
1061   EXPECT_FALSE(eq(a, nullptr));
1062
1063   EXPECT_EQ(hash(*a), hash(a));
1064   EXPECT_NE(0, hash(a));
1065
1066   auto b = fromStr("hello");
1067
1068   EXPECT_TRUE(eq(*a, *b));
1069   EXPECT_TRUE(eq(a, b));
1070
1071   EXPECT_EQ(hash(a), hash(b));
1072
1073   auto c = fromStr("hellow");
1074
1075   EXPECT_FALSE(eq(a, c));
1076   EXPECT_NE(hash(a), hash(c));
1077
1078   auto d = fromStr("world");
1079
1080   EXPECT_FALSE(eq(a, d));
1081   EXPECT_NE(hash(a), hash(d));
1082
1083   auto e = fromStr("helloworld");
1084   auto f = fromStr("hello");
1085   f->prependChain(fromStr("wo"));
1086   f->prependChain(fromStr("rld"));
1087
1088   EXPECT_TRUE(eq(e, f));
1089   EXPECT_EQ(hash(e), hash(f));
1090 }
1091
1092 // reserveSlow() had a bug when reallocating the buffer in place. It would
1093 // preserve old headroom if it's not too much (heuristically) but wouldn't
1094 // adjust the requested amount of memory to account for that; the end result
1095 // would be that reserve() would return with less tailroom than requested.
1096 TEST(IOBuf, ReserveWithHeadroom) {
1097   // This is assuming jemalloc, where we know that 4096 and 8192 bytes are
1098   // valid (and consecutive) allocation sizes. We're hoping that our
1099   // 4096-byte buffer can be expanded in place to 8192 (in practice, this
1100   // usually happens).
1101   const char data[] = "Lorem ipsum dolor sit amet, consectetur adipiscing elit";
1102   constexpr size_t reservedSize = 24;  // sizeof(SharedInfo)
1103   // chosen carefully so that the buffer is exactly 4096 bytes
1104   IOBuf buf(IOBuf::CREATE, 4096 - reservedSize);
1105   buf.advance(10);
1106   memcpy(buf.writableData(), data, sizeof(data));
1107   buf.append(sizeof(data));
1108   EXPECT_EQ(sizeof(data), buf.length());
1109
1110   // Grow the buffer (hopefully in place); this would incorrectly reserve
1111   // the 10 bytes of headroom, giving us 10 bytes less than requested.
1112   size_t tailroom = 8192 - reservedSize - sizeof(data);
1113   buf.reserve(0, tailroom);
1114   EXPECT_LE(tailroom, buf.tailroom());
1115   EXPECT_EQ(sizeof(data), buf.length());
1116   EXPECT_EQ(0, memcmp(data, buf.data(), sizeof(data)));
1117 }
1118
1119 TEST(IOBuf, CopyConstructorAndAssignmentOperator) {
1120   auto buf = IOBuf::create(4096);
1121   append(buf, "hello world");
1122   auto buf2 = IOBuf::create(4096);
1123   append(buf2, " goodbye");
1124   buf->prependChain(std::move(buf2));
1125   EXPECT_FALSE(buf->isShared());
1126
1127   {
1128     auto copy = *buf;
1129     EXPECT_TRUE(buf->isShared());
1130     EXPECT_TRUE(copy.isShared());
1131     EXPECT_EQ((void*)buf->data(), (void*)copy.data());
1132     EXPECT_NE(buf->next(), copy.next());  // actually different buffers
1133
1134     auto copy2 = *buf;
1135     copy2.coalesce();
1136     EXPECT_TRUE(buf->isShared());
1137     EXPECT_TRUE(copy.isShared());
1138     EXPECT_FALSE(copy2.isShared());
1139
1140     auto p = reinterpret_cast<const char*>(copy2.data());
1141     EXPECT_EQ("hello world goodbye", std::string(p, copy2.length()));
1142   }
1143
1144   EXPECT_FALSE(buf->isShared());
1145
1146   {
1147     folly::IOBuf newBuf(folly::IOBuf::CREATE, 4096);
1148     EXPECT_FALSE(newBuf.isShared());
1149
1150     auto newBufCopy = newBuf;
1151     EXPECT_TRUE(newBuf.isShared());
1152     EXPECT_TRUE(newBufCopy.isShared());
1153
1154     newBufCopy = *buf;
1155     EXPECT_TRUE(buf->isShared());
1156     EXPECT_FALSE(newBuf.isShared());
1157     EXPECT_TRUE(newBufCopy.isShared());
1158   }
1159
1160   EXPECT_FALSE(buf->isShared());
1161 }
1162
1163 TEST(IOBuf, CloneAsValue) {
1164   auto buf = IOBuf::create(4096);
1165   append(buf, "hello world");
1166   {
1167     auto buf2 = IOBuf::create(4096);
1168     append(buf2, " goodbye");
1169     buf->prependChain(std::move(buf2));
1170     EXPECT_FALSE(buf->isShared());
1171   }
1172
1173   {
1174     auto copy = buf->cloneOneAsValue();
1175     EXPECT_TRUE(buf->isShared());
1176     EXPECT_TRUE(copy.isShared());
1177     EXPECT_EQ((void*)buf->data(), (void*)copy.data());
1178     EXPECT_TRUE(buf->isChained());
1179     EXPECT_FALSE(copy.isChained());
1180
1181     auto copy2 = buf->cloneAsValue();
1182     EXPECT_TRUE(buf->isShared());
1183     EXPECT_TRUE(copy.isShared());
1184     EXPECT_TRUE(copy2.isShared());
1185     EXPECT_TRUE(buf->isChained());
1186     EXPECT_TRUE(copy2.isChained());
1187
1188     copy.unshareOne();
1189     EXPECT_TRUE(buf->isShared());
1190     EXPECT_FALSE(copy.isShared());
1191     EXPECT_NE((void*)buf->data(), (void*)copy.data());
1192     EXPECT_TRUE(copy2.isShared());
1193
1194     auto p = reinterpret_cast<const char*>(copy.data());
1195     EXPECT_EQ("hello world", std::string(p, copy.length()));
1196
1197     copy2.coalesce();
1198     EXPECT_FALSE(buf->isShared());
1199     EXPECT_FALSE(copy.isShared());
1200     EXPECT_FALSE(copy2.isShared());
1201     EXPECT_FALSE(copy2.isChained());
1202
1203     auto p2 = reinterpret_cast<const char*>(copy2.data());
1204     EXPECT_EQ("hello world goodbye", std::string(p2, copy2.length()));
1205   }
1206
1207   EXPECT_FALSE(buf->isShared());
1208 }
1209
1210 namespace {
1211 // Use with string literals only
1212 std::unique_ptr<IOBuf> wrap(const char* str) {
1213   return IOBuf::wrapBuffer(str, strlen(str));
1214 }
1215
1216 std::unique_ptr<IOBuf> copy(const char* str) {
1217   // At least 1KiB of tailroom, to ensure an external buffer
1218   return IOBuf::copyBuffer(str, strlen(str), 0, 1024);
1219 }
1220
1221 std::string toString(const folly::IOBuf& buf) {
1222   std::string result;
1223   result.reserve(buf.computeChainDataLength());
1224   for (auto& b : buf) {
1225     result.append(reinterpret_cast<const char*>(b.data()), b.size());
1226   }
1227   return result;
1228 }
1229
1230 char* writableStr(folly::IOBuf& buf) {
1231   return reinterpret_cast<char*>(buf.writableData());
1232 }
1233
1234 }  // namespace
1235
1236 TEST(IOBuf, ExternallyShared) {
1237   struct Item {
1238     Item(const char* src, size_t len) : size(len) {
1239       CHECK_LE(len, sizeof(buffer));
1240       memcpy(buffer, src, len);
1241     }
1242     uint32_t refcount{0};
1243     uint8_t size;
1244     char buffer[256];
1245   };
1246
1247   auto hello = "hello";
1248   struct Item it(hello, strlen(hello));
1249
1250   {
1251     auto freeFn = [](void* /* unused */, void* userData) {
1252       auto it = static_cast<struct Item*>(userData);
1253       it->refcount--;
1254     };
1255     it.refcount++;
1256     auto buf1 = IOBuf::takeOwnership(it.buffer, it.size, freeFn, &it);
1257     EXPECT_TRUE(buf1->isManagedOne());
1258     EXPECT_FALSE(buf1->isSharedOne());
1259
1260     buf1->markExternallyShared();
1261     EXPECT_TRUE(buf1->isSharedOne());
1262
1263     {
1264       auto buf2 = buf1->clone();
1265       EXPECT_TRUE(buf2->isManagedOne());
1266       EXPECT_TRUE(buf2->isSharedOne());
1267       EXPECT_EQ(buf1->data(), buf2->data());
1268       EXPECT_EQ(it.refcount, 1);
1269     }
1270     EXPECT_EQ(it.refcount, 1);
1271   }
1272   EXPECT_EQ(it.refcount, 0);
1273 }
1274
1275 TEST(IOBuf, Managed) {
1276   auto hello = "hello";
1277   auto buf1UP = wrap(hello);
1278   auto buf1 = buf1UP.get();
1279   EXPECT_FALSE(buf1->isManagedOne());
1280   auto buf2UP = copy("world");
1281   auto buf2 = buf2UP.get();
1282   EXPECT_TRUE(buf2->isManagedOne());
1283   auto buf3UP = wrap(hello);
1284   auto buf3 = buf3UP.get();
1285   auto buf4UP = buf2->clone();
1286   auto buf4 = buf4UP.get();
1287
1288   // buf1 and buf3 share the same memory (but are unmanaged)
1289   EXPECT_FALSE(buf1->isManagedOne());
1290   EXPECT_FALSE(buf3->isManagedOne());
1291   EXPECT_TRUE(buf1->isSharedOne());
1292   EXPECT_TRUE(buf3->isSharedOne());
1293   EXPECT_EQ(buf1->data(), buf3->data());
1294
1295   // buf2 and buf4 share the same memory (but are managed)
1296   EXPECT_TRUE(buf2->isManagedOne());
1297   EXPECT_TRUE(buf4->isManagedOne());
1298   EXPECT_TRUE(buf2->isSharedOne());
1299   EXPECT_TRUE(buf4->isSharedOne());
1300   EXPECT_EQ(buf2->data(), buf4->data());
1301
1302   buf1->prependChain(std::move(buf2UP));
1303   buf1->prependChain(std::move(buf3UP));
1304   buf1->prependChain(std::move(buf4UP));
1305
1306   EXPECT_EQ("helloworldhelloworld", toString(*buf1));
1307   EXPECT_FALSE(buf1->isManaged());
1308
1309   buf1->makeManaged();
1310   EXPECT_TRUE(buf1->isManaged());
1311
1312   // buf1 and buf3 are now unshared (because they were unmanaged)
1313   EXPECT_TRUE(buf1->isManagedOne());
1314   EXPECT_TRUE(buf3->isManagedOne());
1315   EXPECT_FALSE(buf1->isSharedOne());
1316   EXPECT_FALSE(buf3->isSharedOne());
1317   EXPECT_NE(buf1->data(), buf3->data());
1318
1319   // buf2 and buf4 are still shared
1320   EXPECT_TRUE(buf2->isManagedOne());
1321   EXPECT_TRUE(buf4->isManagedOne());
1322   EXPECT_TRUE(buf2->isSharedOne());
1323   EXPECT_TRUE(buf4->isSharedOne());
1324   EXPECT_EQ(buf2->data(), buf4->data());
1325
1326   // And verify that the truth is what we expect: modify a byte in buf1 and
1327   // buf2, see that the change from buf1 is *not* reflected in buf3, but the
1328   // change from buf2 is reflected in buf4.
1329   writableStr(*buf1)[0] = 'j';
1330   writableStr(*buf2)[0] = 'x';
1331   EXPECT_EQ("jelloxorldhelloxorld", toString(*buf1));
1332 }
1333
1334 TEST(IOBuf, CoalesceEmptyBuffers) {
1335   auto b1 = IOBuf::takeOwnership(nullptr, 0);
1336   auto b2 = fromStr("hello");
1337   auto b3 = IOBuf::takeOwnership(nullptr, 0);
1338
1339   b2->appendChain(std::move(b3));
1340   b1->appendChain(std::move(b2));
1341
1342   auto br = b1->coalesce();
1343
1344   EXPECT_TRUE(ByteRange(StringPiece("hello")) == br);
1345 }