The Tor Browser: xpcom/string/src/nsSubstring.cpp@b8a032363ba2

Incorporate requested changes from Mozilla in review:
https://bugzilla.mozilla.org/show_bug.cgi?id=1123480#c6

     1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */

     2 /* vim:set ts=2 sw=2 sts=2 et cindent: */

     3 /* This Source Code Form is subject to the terms of the Mozilla Public

     4  * License, v. 2.0. If a copy of the MPL was not distributed with this

     5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

     7 #ifdef DEBUG

     8 #define ENABLE_STRING_STATS

     9 #endif

    11 #include "mozilla/Atomics.h"

    12 #include "mozilla/MemoryReporting.h"

    14 #ifdef ENABLE_STRING_STATS

    15 #include <stdio.h>

    16 #endif

    18 #include <stdlib.h>

    19 #include "nsSubstring.h"

    20 #include "nsString.h"

    21 #include "nsStringBuffer.h"

    22 #include "nsDependentString.h"

    23 #include "nsMemory.h"

    24 #include "prprf.h"

    25 #include "nsStaticAtom.h"

    26 #include "nsCOMPtr.h"

    28 #include "mozilla/IntegerPrintfMacros.h"

    29 #ifdef XP_WIN

    30 #include <windows.h>

    31 #include <process.h>

    32 #define getpid() _getpid()

    33 #define pthread_self() GetCurrentThreadId()

    34 #else

    35 #include <pthread.h>

    36 #include <unistd.h>

    37 #endif

    39 using mozilla::Atomic;

    41 // ---------------------------------------------------------------------------

    43 static const char16_t gNullChar = 0;

    45 char* const nsCharTraits<char>::sEmptyBuffer =

    46   (char*) const_cast<char16_t*>(&gNullChar);

    47 char16_t* const nsCharTraits<char16_t>::sEmptyBuffer =

    48   const_cast<char16_t*>(&gNullChar);

    50 // ---------------------------------------------------------------------------

    52 #ifdef ENABLE_STRING_STATS

    53 class nsStringStats

    54   {

    55     public:

    56       nsStringStats()

    57         : mAllocCount(0), mReallocCount(0), mFreeCount(0), mShareCount(0) {}

    59       ~nsStringStats()

    60         {

    61           // this is a hack to suppress duplicate string stats printing

    62           // in seamonkey as a result of the string code being linked

    63           // into seamonkey and libxpcom! :-(

    64           if (!mAllocCount && !mAdoptCount)

    65             return;

    67           printf("nsStringStats\n");

    68           printf(" => mAllocCount:     % 10d\n", int(mAllocCount));

    69           printf(" => mReallocCount:   % 10d\n", int(mReallocCount));

    70           printf(" => mFreeCount:      % 10d", int(mFreeCount));

    71           if (mAllocCount > mFreeCount)

    72             printf("  --  LEAKED %d !!!\n", mAllocCount - mFreeCount);

    73           else

    74             printf("\n");

    75           printf(" => mShareCount:     % 10d\n", int(mShareCount));

    76           printf(" => mAdoptCount:     % 10d\n", int(mAdoptCount));

    77           printf(" => mAdoptFreeCount: % 10d", int(mAdoptFreeCount));

    78           if (mAdoptCount > mAdoptFreeCount)

    79             printf("  --  LEAKED %d !!!\n", mAdoptCount - mAdoptFreeCount);

    80           else

    81             printf("\n");

    82           printf(" => Process ID: %" PRIuPTR ", Thread ID: %" PRIuPTR "\n",

    83                  uintptr_t(getpid()), uintptr_t(pthread_self()));

    84         }

    86       Atomic<int32_t> mAllocCount;

    87       Atomic<int32_t> mReallocCount;

    88       Atomic<int32_t> mFreeCount;

    89       Atomic<int32_t> mShareCount;

    90       Atomic<int32_t> mAdoptCount;

    91       Atomic<int32_t> mAdoptFreeCount;

    92   };

    93 static nsStringStats gStringStats;

    94 #define STRING_STAT_INCREMENT(_s) (gStringStats.m ## _s ## Count)++

    95 #else

    96 #define STRING_STAT_INCREMENT(_s)

    97 #endif

    99 // ---------------------------------------------------------------------------

   101 inline void

   102 ReleaseData( void* data, uint32_t flags )

   103   {

   104     if (flags & nsSubstring::F_SHARED)

   105       {

   106         nsStringBuffer::FromData(data)->Release();

   107       }

   108     else if (flags & nsSubstring::F_OWNED)

   109       {

   110         nsMemory::Free(data);

   111         STRING_STAT_INCREMENT(AdoptFree);

   112 #ifdef NS_BUILD_REFCNT_LOGGING

   113         // Treat this as destruction of a "StringAdopt" object for leak

   114         // tracking purposes.

   115         NS_LogDtor(data, "StringAdopt", 1);

   116 #endif // NS_BUILD_REFCNT_LOGGING

   117       }

   118     // otherwise, nothing to do.

   119   }

   121 // ---------------------------------------------------------------------------

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

   125 class nsAStringAccessor : public nsAString

   126   {

   127     private:

   128       nsAStringAccessor(); // NOT IMPLEMENTED

   130     public:

   131       char_type  *data() const   { return mData; }

   132       size_type   length() const { return mLength; }

   133       uint32_t    flags() const  { return mFlags; }

   135       void set(char_type *data, size_type len, uint32_t flags)

   136         {

   137           ReleaseData(mData, mFlags);

   138           mData = data;

   139           mLength = len;

   140           mFlags = flags;

   141         }

   142   };

   144 class nsACStringAccessor : public nsACString

   145   {

   146     private:

   147       nsACStringAccessor(); // NOT IMPLEMENTED

   149     public:

   150       char_type  *data() const   { return mData; }

   151       size_type   length() const { return mLength; }

   152       uint32_t    flags() const  { return mFlags; }

   154       void set(char_type *data, size_type len, uint32_t flags)

   155         {

   156           ReleaseData(mData, mFlags);

   157           mData = data;

   158           mLength = len;

   159           mFlags = flags;

   160         }

   161   };

   163 // ---------------------------------------------------------------------------

   165 void

   166 nsStringBuffer::AddRef()

   167   {

   168     ++mRefCount;

   169     STRING_STAT_INCREMENT(Share);

   170     NS_LOG_ADDREF(this, mRefCount, "nsStringBuffer", sizeof(*this));

   171   }

   173 void

   174 nsStringBuffer::Release()

   175   {

   176     int32_t count = --mRefCount;

   177     NS_LOG_RELEASE(this, count, "nsStringBuffer");

   178     if (count == 0)

   179       {

   180         STRING_STAT_INCREMENT(Free);

   181         free(this); // we were allocated with |malloc|

   182       }

   183   }

   185   /**

   186    * Alloc returns a pointer to a new string header with set capacity.

   187    */

   188 already_AddRefed<nsStringBuffer>

   189 nsStringBuffer::Alloc(size_t size)

   190   {

   191     NS_ASSERTION(size != 0, "zero capacity allocation not allowed");

   192     NS_ASSERTION(sizeof(nsStringBuffer) + size <= size_t(uint32_t(-1)) &&

   193                  sizeof(nsStringBuffer) + size > size,

   194                  "mStorageSize will truncate");

   196     nsStringBuffer *hdr =

   197         (nsStringBuffer *) malloc(sizeof(nsStringBuffer) + size);

   198     if (hdr)

   199       {

   200         STRING_STAT_INCREMENT(Alloc);

   202         hdr->mRefCount = 1;

   203         hdr->mStorageSize = size;

   204         NS_LOG_ADDREF(hdr, 1, "nsStringBuffer", sizeof(*hdr));

   205       }

   206     return dont_AddRef(hdr);

   207   }

   209 nsStringBuffer*

   210 nsStringBuffer::Realloc(nsStringBuffer* hdr, size_t size)

   211   {

   212     STRING_STAT_INCREMENT(Realloc);

   214     NS_ASSERTION(size != 0, "zero capacity allocation not allowed");

   215     NS_ASSERTION(sizeof(nsStringBuffer) + size <= size_t(uint32_t(-1)) &&

   216                  sizeof(nsStringBuffer) + size > size,

   217                  "mStorageSize will truncate");

   219     // no point in trying to save ourselves if we hit this assertion

   220     NS_ASSERTION(!hdr->IsReadonly(), "|Realloc| attempted on readonly string");

   222     // Treat this as a release and addref for refcounting purposes, since we

   223     // just asserted that the refcount is 1.  If we don't do that, refcount

   224     // logging will claim we've leaked all sorts of stuff.

   225     NS_LOG_RELEASE(hdr, 0, "nsStringBuffer");

   227     hdr = (nsStringBuffer*) realloc(hdr, sizeof(nsStringBuffer) + size);

   228     if (hdr) {

   229       NS_LOG_ADDREF(hdr, 1, "nsStringBuffer", sizeof(*hdr));

   230       hdr->mStorageSize = size;

   231     }

   233     return hdr;

   234   }

   236 nsStringBuffer*

   237 nsStringBuffer::FromString(const nsAString& str)

   238   {

   239     const nsAStringAccessor* accessor =

   240         static_cast<const nsAStringAccessor*>(&str);

   242     if (!(accessor->flags() & nsSubstring::F_SHARED))

   243       return nullptr;

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

   246   }

   248 nsStringBuffer*

   249 nsStringBuffer::FromString(const nsACString& str)

   250   {

   251     const nsACStringAccessor* accessor =

   252         static_cast<const nsACStringAccessor*>(&str);

   254     if (!(accessor->flags() & nsCSubstring::F_SHARED))

   255       return nullptr;

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

   258   }

   260 void

   261 nsStringBuffer::ToString(uint32_t len, nsAString &str,

   262                          bool aMoveOwnership)

   263   {

   264     char16_t* data = static_cast<char16_t*>(Data());

   266     nsAStringAccessor* accessor = static_cast<nsAStringAccessor*>(&str);

   267     NS_ASSERTION(data[len] == char16_t(0), "data should be null terminated");

   269     // preserve class flags

   270     uint32_t flags = accessor->flags();

   271     flags = (flags & 0xFFFF0000) | nsSubstring::F_SHARED | nsSubstring::F_TERMINATED;

   273     if (!aMoveOwnership) {

   274       AddRef();

   275     }

   276     accessor->set(data, len, flags);

   277   }

   279 void

   280 nsStringBuffer::ToString(uint32_t len, nsACString &str,

   281                          bool aMoveOwnership)

   282   {

   283     char* data = static_cast<char*>(Data());

   285     nsACStringAccessor* accessor = static_cast<nsACStringAccessor*>(&str);

   286     NS_ASSERTION(data[len] == char(0), "data should be null terminated");

   288     // preserve class flags

   289     uint32_t flags = accessor->flags();

   290     flags = (flags & 0xFFFF0000) | nsCSubstring::F_SHARED | nsCSubstring::F_TERMINATED;

   292     if (!aMoveOwnership) {

   293       AddRef();

   294     }

   295     accessor->set(data, len, flags);

   296   }

   298 size_t

   299 nsStringBuffer::SizeOfIncludingThisMustBeUnshared(mozilla::MallocSizeOf aMallocSizeOf) const

   300   {

   301     NS_ASSERTION(!IsReadonly(),

   302                  "shared StringBuffer in SizeOfIncludingThisMustBeUnshared");

   303     return aMallocSizeOf(this);

   304   }

   306 size_t

   307 nsStringBuffer::SizeOfIncludingThisIfUnshared(mozilla::MallocSizeOf aMallocSizeOf) const

   308   {

   309     if (!IsReadonly())

   310       {

   311         return SizeOfIncludingThisMustBeUnshared(aMallocSizeOf);

   312       }

   313     return 0;

   314   }

   316 size_t

   317 nsStringBuffer::SizeOfIncludingThisEvenIfShared(mozilla::MallocSizeOf aMallocSizeOf) const

   318   {

   319     return aMallocSizeOf(this);

   320   }

   322 // ---------------------------------------------------------------------------

   325   // define nsSubstring

   326 #include "string-template-def-unichar.h"

   327 #include "nsTSubstring.cpp"

   328 #include "string-template-undef.h"

   330   // define nsCSubstring

   331 #include "string-template-def-char.h"

   332 #include "nsTSubstring.cpp"

   333 #include "string-template-undef.h"

   335 // Check that internal and external strings have the same size.

   336 // See https://bugzilla.mozilla.org/show_bug.cgi?id=430581

   338 #include "prlog.h"

   339 #include "nsXPCOMStrings.h"

   341 static_assert(sizeof(nsStringContainer_base) == sizeof(nsSubstring),

   342               "internal and external strings must have the same size");

The Tor Browser / file revision

xpcom/string/src/nsSubstring.cpp@b8a032363ba2

xpcom/string/src/nsSubstring.cpp