DXR is a code search and navigation tool aimed at making sense of large projects. It supports full-text and regex searches as well as structural queries.

Mercurial (dc32c9061a0a)

VCS Links

Line Code
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#ifdef DEBUG
#  define ENABLE_STRING_STATS
#endif

#include "mozilla/Atomics.h"
#include "mozilla/MemoryReporting.h"

#ifdef ENABLE_STRING_STATS
#  include <stdio.h>
#endif

#include <stdlib.h>
#include "nsAString.h"
#include "nsString.h"
#include "nsStringBuffer.h"
#include "nsDependentString.h"
#include "nsPrintfCString.h"
#include "nsMemory.h"
#include "prprf.h"
#include "nsCOMPtr.h"

#include "mozilla/IntegerPrintfMacros.h"
#ifdef XP_WIN
#  include <windows.h>
#  include <process.h>
#  define getpid() _getpid()
#  define pthread_self() GetCurrentThreadId()
#else
#  include <pthread.h>
#  include <unistd.h>
#endif

#ifdef STRING_BUFFER_CANARY
#  define CHECK_STRING_BUFFER_CANARY(c)                      \
    do {                                                     \
      if ((c) != CANARY_OK) {                                \
        MOZ_CRASH_UNSAFE_PRINTF("Bad canary value 0x%x", c); \
      }                                                      \
    } while (0)
#else
#  define CHECK_STRING_BUFFER_CANARY(c) \
    do {                                \
    } while (0)
#endif

using mozilla::Atomic;

// ---------------------------------------------------------------------------

static const char16_t gNullChar = 0;

char* const nsCharTraits<char>::sEmptyBuffer =
    (char*)const_cast<char16_t*>(&gNullChar);
char16_t* const nsCharTraits<char16_t>::sEmptyBuffer =
    const_cast<char16_t*>(&gNullChar);

// ---------------------------------------------------------------------------

#ifdef ENABLE_STRING_STATS
class nsStringStats {
 public:
  nsStringStats()
      : mAllocCount(0), mReallocCount(0), mFreeCount(0), mShareCount(0) {}

  ~nsStringStats() {
    // this is a hack to suppress duplicate string stats printing
    // in seamonkey as a result of the string code being linked
    // into seamonkey and libxpcom! :-(
    if (!mAllocCount && !mAdoptCount) {
      return;
    }

    printf("nsStringStats\n");
    printf(" => mAllocCount:     % 10d\n", int(mAllocCount));
    printf(" => mReallocCount:   % 10d\n", int(mReallocCount));
    printf(" => mFreeCount:      % 10d", int(mFreeCount));
    if (mAllocCount > mFreeCount) {
      printf("  --  LEAKED %d !!!\n", mAllocCount - mFreeCount);
    } else {
      printf("\n");
    }
    printf(" => mShareCount:     % 10d\n", int(mShareCount));
    printf(" => mAdoptCount:     % 10d\n", int(mAdoptCount));
    printf(" => mAdoptFreeCount: % 10d", int(mAdoptFreeCount));
    if (mAdoptCount > mAdoptFreeCount) {
      printf("  --  LEAKED %d !!!\n", mAdoptCount - mAdoptFreeCount);
    } else {
      printf("\n");
    }
    printf(" => Process ID: %" PRIuPTR ", Thread ID: %" PRIuPTR "\n",
           uintptr_t(getpid()), uintptr_t(pthread_self()));
  }

  typedef Atomic<int32_t, mozilla::SequentiallyConsistent,
                 mozilla::recordreplay::Behavior::DontPreserve>
      AtomicInt;

  AtomicInt mAllocCount;
  AtomicInt mReallocCount;
  AtomicInt mFreeCount;
  AtomicInt mShareCount;
  AtomicInt mAdoptCount;
  AtomicInt mAdoptFreeCount;
};
static nsStringStats gStringStats;
#  define STRING_STAT_INCREMENT(_s) (gStringStats.m##_s##Count)++
#else
#  define STRING_STAT_INCREMENT(_s)
#endif

// ---------------------------------------------------------------------------

void ReleaseData(void* aData, nsAString::DataFlags aFlags) {
  if (aFlags & nsAString::DataFlags::REFCOUNTED) {
    nsStringBuffer::FromData(aData)->Release();
  } else if (aFlags & nsAString::DataFlags::OWNED) {
    free(aData);
    STRING_STAT_INCREMENT(AdoptFree);
    // Treat this as destruction of a "StringAdopt" object for leak
    // tracking purposes.
    MOZ_LOG_DTOR(aData, "StringAdopt", 1);
  }
  // otherwise, nothing to do.
}

// ---------------------------------------------------------------------------

// XXX or we could make nsStringBuffer be a friend of nsTAString

class nsAStringAccessor : public nsAString {
 private:
  nsAStringAccessor();  // NOT IMPLEMENTED

 public:
  char_type* data() const { return mData; }
  size_type length() const { return mLength; }
  DataFlags flags() const { return mDataFlags; }

  void set(char_type* aData, size_type aLen, DataFlags aDataFlags) {
    ReleaseData(mData, mDataFlags);
    SetData(aData, aLen, aDataFlags);
  }
};

class nsACStringAccessor : public nsACString {
 private:
  nsACStringAccessor();  // NOT IMPLEMENTED

 public:
  char_type* data() const { return mData; }
  size_type length() const { return mLength; }
  DataFlags flags() const { return mDataFlags; }

  void set(char_type* aData, size_type aLen, DataFlags aDataFlags) {
    ReleaseData(mData, mDataFlags);
    SetData(aData, aLen, aDataFlags);
  }
};

// ---------------------------------------------------------------------------

void nsStringBuffer::AddRef() {
  // Memory synchronization is not required when incrementing a
  // reference count.  The first increment of a reference count on a
  // thread is not important, since the first use of the object on a
  // thread can happen before it.  What is important is the transfer
  // of the pointer to that thread, which may happen prior to the
  // first increment on that thread.  The necessary memory
  // synchronization is done by the mechanism that transfers the
  // pointer between threads.
#ifdef NS_BUILD_REFCNT_LOGGING
  uint32_t count =
#endif
      mRefCount.fetch_add(1, std::memory_order_relaxed)
#ifdef NS_BUILD_REFCNT_LOGGING
      + 1
#endif
      ;
  STRING_STAT_INCREMENT(Share);
  NS_LOG_ADDREF(this, count, "nsStringBuffer", sizeof(*this));
}

void nsStringBuffer::Release() {
  CHECK_STRING_BUFFER_CANARY(mCanary);

  // Since this may be the last release on this thread, we need
  // release semantics so that prior writes on this thread are visible
  // to the thread that destroys the object when it reads mValue with
  // acquire semantics.
  uint32_t count = mRefCount.fetch_sub(1, std::memory_order_release) - 1;
  NS_LOG_RELEASE(this, count, "nsStringBuffer");
  if (count == 0) {
    // We're going to destroy the object on this thread, so we need
    // acquire semantics to synchronize with the memory released by
    // the last release on other threads, that is, to ensure that
    // writes prior to that release are now visible on this thread.
    count = mRefCount.load(std::memory_order_acquire);
#ifdef STRING_BUFFER_CANARY
    mCanary = CANARY_POISON;
#endif

    STRING_STAT_INCREMENT(Free);
    free(this);  // we were allocated with |malloc|
  }
}

/**
 * Alloc returns a pointer to a new string header with set capacity.
 */
already_AddRefed<nsStringBuffer> nsStringBuffer::Alloc(size_t aSize) {
  NS_ASSERTION(aSize != 0, "zero capacity allocation not allowed");
  NS_ASSERTION(sizeof(nsStringBuffer) + aSize <= size_t(uint32_t(-1)) &&
                   sizeof(nsStringBuffer) + aSize > aSize,
               "mStorageSize will truncate");

  nsStringBuffer* hdr = (nsStringBuffer*)malloc(sizeof(nsStringBuffer) + aSize);
  if (hdr) {
    STRING_STAT_INCREMENT(Alloc);

    hdr->mRefCount = 1;
    hdr->mStorageSize = aSize;
#ifdef STRING_BUFFER_CANARY
    hdr->mCanary = CANARY_OK;
#endif
    NS_LOG_ADDREF(hdr, 1, "nsStringBuffer", sizeof(*hdr));
  }
  return dont_AddRef(hdr);
}

nsStringBuffer* nsStringBuffer::Realloc(nsStringBuffer* aHdr, size_t aSize) {
  STRING_STAT_INCREMENT(Realloc);

  CHECK_STRING_BUFFER_CANARY(aHdr->mCanary);
  NS_ASSERTION(aSize != 0, "zero capacity allocation not allowed");
  NS_ASSERTION(sizeof(nsStringBuffer) + aSize <= size_t(uint32_t(-1)) &&
                   sizeof(nsStringBuffer) + aSize > aSize,
               "mStorageSize will truncate");

  // no point in trying to save ourselves if we hit this assertion
  NS_ASSERTION(!aHdr->IsReadonly(), "|Realloc| attempted on readonly string");

  // Treat this as a release and addref for refcounting purposes, since we
  // just asserted that the refcount is 1.  If we don't do that, refcount
  // logging will claim we've leaked all sorts of stuff.
  NS_LOG_RELEASE(aHdr, 0, "nsStringBuffer");

  aHdr = (nsStringBuffer*)realloc(aHdr, sizeof(nsStringBuffer) + aSize);
  if (aHdr) {
    NS_LOG_ADDREF(aHdr, 1, "nsStringBuffer", sizeof(*aHdr));
    aHdr->mStorageSize = aSize;
  }

  return aHdr;
}

nsStringBuffer* nsStringBuffer::FromString(const nsAString& aStr) {
  const nsAStringAccessor* accessor =
      static_cast<const nsAStringAccessor*>(&aStr);

  if (!(accessor->flags() & nsAString::DataFlags::REFCOUNTED)) {
    return nullptr;
  }

  return FromData(accessor->data());
}

nsStringBuffer* nsStringBuffer::FromString(const nsACString& aStr) {
  const nsACStringAccessor* accessor =
      static_cast<const nsACStringAccessor*>(&aStr);

  if (!(accessor->flags() & nsACString::DataFlags::REFCOUNTED)) {
    return nullptr;
  }

  return FromData(accessor->data());
}

void nsStringBuffer::ToString(uint32_t aLen, nsAString& aStr,
                              bool aMoveOwnership) {
  char16_t* data = static_cast<char16_t*>(Data());

  nsAStringAccessor* accessor = static_cast<nsAStringAccessor*>(&aStr);
  MOZ_DIAGNOSTIC_ASSERT(data[aLen] == char16_t(0),
                        "data should be null terminated");

  nsAString::DataFlags flags =
      nsAString::DataFlags::REFCOUNTED | nsAString::DataFlags::TERMINATED;

  if (!aMoveOwnership) {
    AddRef();
  }
  accessor->set(data, aLen, flags);
}

void nsStringBuffer::ToString(uint32_t aLen, nsACString& aStr,
                              bool aMoveOwnership) {
  char* data = static_cast<char*>(Data());

  nsACStringAccessor* accessor = static_cast<nsACStringAccessor*>(&aStr);
  MOZ_DIAGNOSTIC_ASSERT(data[aLen] == char(0),
                        "data should be null terminated");

  nsACString::DataFlags flags =
      nsACString::DataFlags::REFCOUNTED | nsACString::DataFlags::TERMINATED;

  if (!aMoveOwnership) {
    AddRef();
  }
  accessor->set(data, aLen, flags);
}

size_t nsStringBuffer::SizeOfIncludingThisIfUnshared(
    mozilla::MallocSizeOf aMallocSizeOf) const {
  return IsReadonly() ? 0 : aMallocSizeOf(this);
}

size_t nsStringBuffer::SizeOfIncludingThisEvenIfShared(
    mozilla::MallocSizeOf aMallocSizeOf) const {
  return aMallocSizeOf(this);
}

#ifdef STRING_BUFFER_CANARY
void nsStringBuffer::FromDataCanaryCheckFailed() const {
  MOZ_CRASH_UNSAFE_PRINTF("Bad canary value 0x%x in FromData", mCanary);
}
#endif

// ---------------------------------------------------------------------------

// define nsAString
#include "nsTSubstring.cpp"

// Provide rust bindings to the nsA[C]String types
extern "C" {

// This is a no-op on release, so we ifdef it out such that using it in release
// results in a linker error.
#ifdef DEBUG
void Gecko_IncrementStringAdoptCount(void* aData) {
  MOZ_LOG_CTOR(aData, "StringAdopt", 1);
}
#elif defined(MOZ_DEBUG_RUST)
void Gecko_IncrementStringAdoptCount(void* aData) {}
#endif

void Gecko_FinalizeCString(nsACString* aThis) { aThis->~nsACString(); }

void Gecko_AssignCString(nsACString* aThis, const nsACString* aOther) {
  aThis->Assign(*aOther);
}

void Gecko_TakeFromCString(nsACString* aThis, nsACString* aOther) {
  aThis->Assign(std::move(*aOther));
}

void Gecko_AppendCString(nsACString* aThis, const nsACString* aOther) {
  aThis->Append(*aOther);
}

void Gecko_SetLengthCString(nsACString* aThis, uint32_t aLength) {
  aThis->SetLength(aLength);
}

bool Gecko_FallibleAssignCString(nsACString* aThis, const nsACString* aOther) {
  return aThis->Assign(*aOther, mozilla::fallible);
}

bool Gecko_FallibleTakeFromCString(nsACString* aThis, nsACString* aOther) {
  return aThis->Assign(std::move(*aOther), mozilla::fallible);
}

bool Gecko_FallibleAppendCString(nsACString* aThis, const nsACString* aOther) {
  return aThis->Append(*aOther, mozilla::fallible);
}

bool Gecko_FallibleSetLengthCString(nsACString* aThis, uint32_t aLength) {
  return aThis->SetLength(aLength, mozilla::fallible);
}

char* Gecko_BeginWritingCString(nsACString* aThis) {
  return aThis->BeginWriting();
}

char* Gecko_FallibleBeginWritingCString(nsACString* aThis) {
  return aThis->BeginWriting(mozilla::fallible);
}

uint32_t Gecko_StartBulkWriteCString(nsACString* aThis, uint32_t aCapacity,
                                     uint32_t aUnitsToPreserve,
                                     bool aAllowShrinking) {
  return aThis->StartBulkWriteImpl(aCapacity, aUnitsToPreserve, aAllowShrinking)
      .unwrapOr(UINT32_MAX);
}

void Gecko_FinalizeString(nsAString* aThis) { aThis->~nsAString(); }

void Gecko_AssignString(nsAString* aThis, const nsAString* aOther) {
  aThis->Assign(*aOther);
}

void Gecko_TakeFromString(nsAString* aThis, nsAString* aOther) {
  aThis->Assign(std::move(*aOther));
}

void Gecko_AppendString(nsAString* aThis, const nsAString* aOther) {
  aThis->Append(*aOther);
}

void Gecko_SetLengthString(nsAString* aThis, uint32_t aLength) {
  aThis->SetLength(aLength);
}

bool Gecko_FallibleAssignString(nsAString* aThis, const nsAString* aOther) {
  return aThis->Assign(*aOther, mozilla::fallible);
}

bool Gecko_FallibleTakeFromString(nsAString* aThis, nsAString* aOther) {
  return aThis->Assign(std::move(*aOther), mozilla::fallible);
}

bool Gecko_FallibleAppendString(nsAString* aThis, const nsAString* aOther) {
  return aThis->Append(*aOther, mozilla::fallible);
}

bool Gecko_FallibleSetLengthString(nsAString* aThis, uint32_t aLength) {
  return aThis->SetLength(aLength, mozilla::fallible);
}

char16_t* Gecko_BeginWritingString(nsAString* aThis) {
  return aThis->BeginWriting();
}

char16_t* Gecko_FallibleBeginWritingString(nsAString* aThis) {
  return aThis->BeginWriting(mozilla::fallible);
}

uint32_t Gecko_StartBulkWriteString(nsAString* aThis, uint32_t aCapacity,
                                    uint32_t aUnitsToPreserve,
                                    bool aAllowShrinking) {
  return aThis->StartBulkWriteImpl(aCapacity, aUnitsToPreserve, aAllowShrinking)
      .unwrapOr(UINT32_MAX);
}

}  // extern "C"