The Tor Browser: ipc/chromium/src/base/pickle.cc@6474c204b198 (annotated)

ipc/chromium/src/base/pickle.cc@6474c204b198 (annotated)

ipc/chromium/src/base/pickle.cc

Wed, 31 Dec 2014 06:09:35 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Wed, 31 Dec 2014 06:09:35 +0100
changeset 0: 6474c204b198
permissions: -rw-r--r--

Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.

 // Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 #include "base/pickle.h"
 #include "mozilla/Alignment.h"
 #include "mozilla/Endian.h"
 #include "mozilla/TypeTraits.h"
 #include <stdlib.h>
 #include <limits>
 #include <string>
 #include <algorithm>
 #include "nsDebug.h"
 //------------------------------------------------------------------------------
 static_assert(MOZ_ALIGNOF(Pickle::memberAlignmentType) >= MOZ_ALIGNOF(uint32_t),
               "Insufficient alignment");
 // static
 const int Pickle::kPayloadUnit = 64;
 // We mark a read only pickle with a special capacity_.
 static const uint32_t kCapacityReadOnly = (uint32_t) -1;
 static const char kBytePaddingMarker = char(0xbf);
 namespace {
 // We want to copy data to our payload as efficiently as possible.
 // memcpy fits the bill for copying, but not all compilers or
 // architectures support inlining memcpy from void*, which has unknown
 // static alignment.  However, we know that all the members of our
 // payload will be aligned on memberAlignmentType boundaries.  We
 // therefore use that knowledge to construct a copier that will copy
 // efficiently (via standard C++ assignment mechanisms) if the datatype
 // needs that alignment or less, and memcpy otherwise.  (The compiler
 // may still inline memcpy, of course.)
 template<typename T, size_t size, bool hasSufficientAlignment>
 struct Copier
 {
   static void Copy(T* dest, void** iter) {
     memcpy(dest, *iter, sizeof(T));
   }
 };
 // Copying 64-bit quantities happens often enough and can easily be made
 // worthwhile on 32-bit platforms, so handle it specially.  Only do it
 // if 64-bit types aren't sufficiently aligned; the alignment
 // requirements for them vary between 32-bit platforms.
 #ifndef HAVE_64BIT_OS
 template<typename T>
 struct Copier<T, sizeof(uint64_t), false>
 {
   static void Copy(T* dest, void** iter) {
 #if MOZ_LITTLE_ENDIAN
     static const int loIndex = 0, hiIndex = 1;
 #else
     static const int loIndex = 1, hiIndex = 0;
 #endif
     static_assert(MOZ_ALIGNOF(uint32_t*) == MOZ_ALIGNOF(void*),
                   "Pointers have different alignments");
     uint32_t* src = *reinterpret_cast<uint32_t**>(iter);
     uint32_t* uint32dest = reinterpret_cast<uint32_t*>(dest);
     uint32dest[loIndex] = src[loIndex];
     uint32dest[hiIndex] = src[hiIndex];
   }
 };
 #endif
 template<typename T, size_t size>
 struct Copier<T, size, true>
 {
   static void Copy(T* dest, void** iter) {
     // The reinterpret_cast is only safe if two conditions hold:
     // (1) If the alignment of T* is the same as void*;
     // (2) The alignment of the data in *iter is at least as
     //     big as MOZ_ALIGNOF(T).
     // Check the first condition, as the second condition is already
     // known to be true, or we wouldn't be here.
     static_assert(MOZ_ALIGNOF(T*) == MOZ_ALIGNOF(void*),
                   "Pointers have different alignments");
     *dest = *(*reinterpret_cast<T**>(iter));
   }
 };
 template<typename T>
 void CopyFromIter(T* dest, void** iter) {
   static_assert(mozilla::IsPod<T>::value, "Copied type must be a POD type");
   Copier<T, sizeof(T), (MOZ_ALIGNOF(T) <= sizeof(Pickle::memberAlignmentType))>::Copy(dest, iter);
 }
 } // anonymous namespace
 // Payload is sizeof(Pickle::memberAlignmentType) aligned.
 Pickle::Pickle()
     : header_(NULL),
       header_size_(sizeof(Header)),
       capacity_(0),
       variable_buffer_offset_(0) {
   Resize(kPayloadUnit);
   header_->payload_size = 0;
 }
 Pickle::Pickle(int header_size)
     : header_(NULL),
       header_size_(AlignInt(header_size)),
       capacity_(0),
       variable_buffer_offset_(0) {
   DCHECK(static_cast<memberAlignmentType>(header_size) >= sizeof(Header));
   DCHECK(header_size <= kPayloadUnit);
   Resize(kPayloadUnit);
   if (!header_) {
     NS_ABORT_OOM(kPayloadUnit);
   }
   header_->payload_size = 0;
 }
 Pickle::Pickle(const char* data, int data_len)
     : header_(reinterpret_cast<Header*>(const_cast<char*>(data))),
       header_size_(data_len - header_->payload_size),
       capacity_(kCapacityReadOnly),
       variable_buffer_offset_(0) {
   DCHECK(header_size_ >= sizeof(Header));
   DCHECK(header_size_ == AlignInt(header_size_));
 }
 Pickle::Pickle(const Pickle& other)
     : header_(NULL),
       header_size_(other.header_size_),
       capacity_(0),
       variable_buffer_offset_(other.variable_buffer_offset_) {
   uint32_t payload_size = header_size_ + other.header_->payload_size;
   bool resized = Resize(payload_size);
   if (!resized) {
     NS_ABORT_OOM(payload_size);
   }
   memcpy(header_, other.header_, payload_size);
 }
 Pickle::~Pickle() {
   if (capacity_ != kCapacityReadOnly)
     free(header_);
 }
 Pickle& Pickle::operator=(const Pickle& other) {
   if (header_size_ != other.header_size_ && capacity_ != kCapacityReadOnly) {
     free(header_);
     header_ = NULL;
     header_size_ = other.header_size_;
   }
   bool resized = Resize(other.header_size_ + other.header_->payload_size);
   if (!resized) {
     NS_ABORT_OOM(other.header_size_ + other.header_->payload_size);
   }
   memcpy(header_, other.header_, header_size_ + other.header_->payload_size);
   variable_buffer_offset_ = other.variable_buffer_offset_;
   return *this;
 }
 bool Pickle::ReadBool(void** iter, bool* result) const {
   DCHECK(iter);
   int tmp;
   if (!ReadInt(iter, &tmp))
     return false;
   DCHECK(0 == tmp || 1 == tmp);
   *result = tmp ? true : false;
   return true;
 }
 bool Pickle::ReadInt16(void** iter, int16_t* result) const {
   DCHECK(iter);
   if (!*iter)
     *iter = const_cast<char*>(payload());
   if (!IteratorHasRoomFor(*iter, sizeof(*result)))
     return false;
   CopyFromIter(result, iter);
   UpdateIter(iter, sizeof(*result));
   return true;
 }
 bool Pickle::ReadUInt16(void** iter, uint16_t* result) const {
   DCHECK(iter);
   if (!*iter)
     *iter = const_cast<char*>(payload());
   if (!IteratorHasRoomFor(*iter, sizeof(*result)))
     return false;
   CopyFromIter(result, iter);
   UpdateIter(iter, sizeof(*result));
   return true;
 }
 bool Pickle::ReadInt(void** iter, int* result) const {
   DCHECK(iter);
   if (!*iter)
     *iter = const_cast<char*>(payload());
   if (!IteratorHasRoomFor(*iter, sizeof(*result)))
     return false;
   CopyFromIter(result, iter);
   UpdateIter(iter, sizeof(*result));
   return true;
 }
 // Always written as a 64-bit value since the size for this type can
 // differ between architectures.
 bool Pickle::ReadLong(void** iter, long* result) const {
   DCHECK(iter);
   if (!*iter)
     *iter = const_cast<char*>(payload());
   int64_t bigResult = 0;
   if (!IteratorHasRoomFor(*iter, sizeof(bigResult)))
     return false;
   CopyFromIter(&bigResult, iter);
   DCHECK(bigResult <= LONG_MAX && bigResult >= LONG_MIN);
   *result = static_cast<long>(bigResult);
   UpdateIter(iter, sizeof(bigResult));
   return true;
 }
 // Always written as a 64-bit value since the size for this type can
 // differ between architectures.
 bool Pickle::ReadULong(void** iter, unsigned long* result) const {
   DCHECK(iter);
   if (!*iter)
     *iter = const_cast<char*>(payload());
   uint64_t bigResult = 0;
   if (!IteratorHasRoomFor(*iter, sizeof(bigResult)))
     return false;
   CopyFromIter(&bigResult, iter);
   DCHECK(bigResult <= ULONG_MAX);
   *result = static_cast<unsigned long>(bigResult);
   UpdateIter(iter, sizeof(bigResult));
   return true;
 }
 bool Pickle::ReadLength(void** iter, int* result) const {
   if (!ReadInt(iter, result))
     return false;
   return ((*result) >= 0);
 }
 // Always written as a 64-bit value since the size for this type can
 // differ between architectures.
 bool Pickle::ReadSize(void** iter, size_t* result) const {
   DCHECK(iter);
   if (!*iter)
     *iter = const_cast<char*>(payload());
   uint64_t bigResult = 0;
   if (!IteratorHasRoomFor(*iter, sizeof(bigResult)))
     return false;
   CopyFromIter(&bigResult, iter);
   DCHECK(bigResult <= std::numeric_limits<size_t>::max());
   *result = static_cast<size_t>(bigResult);
   UpdateIter(iter, sizeof(bigResult));
   return true;
 }
 bool Pickle::ReadInt32(void** iter, int32_t* result) const {
   DCHECK(iter);
   if (!*iter)
     *iter = const_cast<char*>(payload());
   if (!IteratorHasRoomFor(*iter, sizeof(*result)))
     return false;
   CopyFromIter(result, iter);
   UpdateIter(iter, sizeof(*result));
   return true;
 }
 bool Pickle::ReadUInt32(void** iter, uint32_t* result) const {
   DCHECK(iter);
   if (!*iter)
     *iter = const_cast<char*>(payload());
   if (!IteratorHasRoomFor(*iter, sizeof(*result)))
     return false;
   CopyFromIter(result, iter);
   UpdateIter(iter, sizeof(*result));
   return true;
 }
 bool Pickle::ReadInt64(void** iter, int64_t* result) const {
   DCHECK(iter);
   if (!*iter)
     *iter = const_cast<char*>(payload());
   if (!IteratorHasRoomFor(*iter, sizeof(*result)))
     return false;
   CopyFromIter(result, iter);
   UpdateIter(iter, sizeof(*result));
   return true;
 }
 bool Pickle::ReadUInt64(void** iter, uint64_t* result) const {
   DCHECK(iter);
   if (!*iter)
     *iter = const_cast<char*>(payload());
   if (!IteratorHasRoomFor(*iter, sizeof(*result)))
     return false;
   CopyFromIter(result, iter);
   UpdateIter(iter, sizeof(*result));
   return true;
 }
 bool Pickle::ReadDouble(void** iter, double* result) const {
   DCHECK(iter);
   if (!*iter)
     *iter = const_cast<char*>(payload());
   if (!IteratorHasRoomFor(*iter, sizeof(*result)))
     return false;
   CopyFromIter(result, iter);
   UpdateIter(iter, sizeof(*result));
   return true;
 }
 // Always written as a 64-bit value since the size for this type can
 // differ between architectures.
 bool Pickle::ReadIntPtr(void** iter, intptr_t* result) const {
   DCHECK(iter);
   if (!*iter)
     *iter = const_cast<char*>(payload());
   int64_t bigResult = 0;
   if (!IteratorHasRoomFor(*iter, sizeof(bigResult)))
     return false;
   CopyFromIter(&bigResult, iter);
   DCHECK(bigResult <= std::numeric_limits<intptr_t>::max() && bigResult >= std::numeric_limits<intptr_t>::min());
   *result = static_cast<intptr_t>(bigResult);
   UpdateIter(iter, sizeof(bigResult));
   return true;
 }
 bool Pickle::ReadUnsignedChar(void** iter, unsigned char* result) const {
   DCHECK(iter);
   if (!*iter)
     *iter = const_cast<char*>(payload());
   if (!IteratorHasRoomFor(*iter, sizeof(*result)))
     return false;
   CopyFromIter(result, iter);
   UpdateIter(iter, sizeof(*result));
   return true;
 }
 bool Pickle::ReadString(void** iter, std::string* result) const {
   DCHECK(iter);
   if (!*iter)
     *iter = const_cast<char*>(payload());
   int len;
   if (!ReadLength(iter, &len))
     return false;
   if (!IteratorHasRoomFor(*iter, len))
     return false;
   char* chars = reinterpret_cast<char*>(*iter);
   result->assign(chars, len);
   UpdateIter(iter, len);
   return true;
 }
 bool Pickle::ReadWString(void** iter, std::wstring* result) const {
   DCHECK(iter);
   if (!*iter)
     *iter = const_cast<char*>(payload());
   int len;
   if (!ReadLength(iter, &len))
     return false;
   if (!IteratorHasRoomFor(*iter, len * sizeof(wchar_t)))
     return false;
   wchar_t* chars = reinterpret_cast<wchar_t*>(*iter);
   result->assign(chars, len);
   UpdateIter(iter, len * sizeof(wchar_t));
   return true;
 }
 bool Pickle::ReadString16(void** iter, string16* result) const {
   DCHECK(iter);
   if (!*iter)
     *iter = const_cast<char*>(payload());
   int len;
   if (!ReadLength(iter, &len))
     return false;
   if (!IteratorHasRoomFor(*iter, len))
     return false;
   char16* chars = reinterpret_cast<char16*>(*iter);
   result->assign(chars, len);
   UpdateIter(iter, len * sizeof(char16));
   return true;
 }
 bool Pickle::ReadBytes(void** iter, const char** data, int length,
                        uint32_t alignment) const {
   DCHECK(iter);
   DCHECK(data);
   DCHECK(alignment == 4 || alignment == 8);
   DCHECK(intptr_t(header_) % alignment == 0);
   if (!*iter)
     *iter = const_cast<char*>(payload());
   uint32_t paddingLen = intptr_t(*iter) % alignment;
   if (paddingLen) {
 #ifdef DEBUG
     {
       const char* padding = static_cast<const char*>(*iter);
       for (uint32_t i = 0; i < paddingLen; i++) {
         DCHECK(*(padding + i) == kBytePaddingMarker);
       }
     }
 #endif
     length += paddingLen;
   }
   if (!IteratorHasRoomFor(*iter, length))
     return false;
   *data = static_cast<const char*>(*iter) + paddingLen;
   DCHECK(intptr_t(*data) % alignment == 0);
   UpdateIter(iter, length);
   return true;
 }
 bool Pickle::ReadData(void** iter, const char** data, int* length) const {
   DCHECK(iter);
   DCHECK(data);
   DCHECK(length);
   if (!*iter)
     *iter = const_cast<char*>(payload());
   if (!ReadLength(iter, length))
     return false;
   return ReadBytes(iter, data, *length);
 }
 char* Pickle::BeginWrite(uint32_t length, uint32_t alignment) {
   DCHECK(alignment % 4 == 0) << "Must be at least 32-bit aligned!";
   // write at an alignment-aligned offset from the beginning of the header
   uint32_t offset = AlignInt(header_->payload_size);
   uint32_t padding = (header_size_ + offset) %  alignment;
   uint32_t new_size = offset + padding + AlignInt(length);
   uint32_t needed_size = header_size_ + new_size;
   if (needed_size > capacity_ && !Resize(std::max(capacity_ * 2, needed_size)))
     return NULL;
   DCHECK(intptr_t(header_) % alignment == 0);
 #ifdef ARCH_CPU_64_BITS
   DCHECK_LE(length, std::numeric_limits<uint32_t>::max());
 #endif
   char* buffer = payload() + offset;
   if (padding) {
     memset(buffer, kBytePaddingMarker, padding);
     buffer += padding;
   }
   DCHECK(intptr_t(buffer) % alignment == 0);
   header_->payload_size = new_size;
 #ifdef MOZ_VALGRIND
   // pad the trailing end as well, so that valgrind
   // doesn't complain when we write the buffer
   padding = AlignInt(length) - length;
   if (padding) {
     memset(buffer + length, kBytePaddingMarker, padding);
   }
 #endif
   return buffer;
 }
 void Pickle::EndWrite(char* dest, int length) {
   // Zero-pad to keep tools like purify from complaining about uninitialized
   // memory.
   if (length % sizeof(memberAlignmentType))
     memset(dest + length, 0,
 	   sizeof(memberAlignmentType) - (length % sizeof(memberAlignmentType)));
 }
 bool Pickle::WriteBytes(const void* data, int data_len, uint32_t alignment) {
   DCHECK(capacity_ != kCapacityReadOnly) << "oops: pickle is readonly";
   DCHECK(alignment == 4 || alignment == 8);
   DCHECK(intptr_t(header_) % alignment == 0);
   char* dest = BeginWrite(data_len, alignment);
   if (!dest)
     return false;
   memcpy(dest, data, data_len);
   EndWrite(dest, data_len);
   return true;
 }
 bool Pickle::WriteString(const std::string& value) {
   if (!WriteInt(static_cast<int>(value.size())))
     return false;
   return WriteBytes(value.data(), static_cast<int>(value.size()));
 }
 bool Pickle::WriteWString(const std::wstring& value) {
   if (!WriteInt(static_cast<int>(value.size())))
     return false;
   return WriteBytes(value.data(),
                     static_cast<int>(value.size() * sizeof(wchar_t)));
 }
 bool Pickle::WriteString16(const string16& value) {
   if (!WriteInt(static_cast<int>(value.size())))
     return false;
   return WriteBytes(value.data(),
                     static_cast<int>(value.size()) * sizeof(char16));
 }
 bool Pickle::WriteData(const char* data, int length) {
   return WriteInt(length) && WriteBytes(data, length);
 }
 char* Pickle::BeginWriteData(int length) {
   DCHECK_EQ(variable_buffer_offset_, 0U) <<
     "There can only be one variable buffer in a Pickle";
   if (!WriteInt(length))
     return NULL;
   char *data_ptr = BeginWrite(length, sizeof(memberAlignmentType));
   if (!data_ptr)
     return NULL;
   variable_buffer_offset_ =
       data_ptr - reinterpret_cast<char*>(header_) - sizeof(int);
   // EndWrite doesn't necessarily have to be called after the write operation,
   // so we call it here to pad out what the caller will eventually write.
   EndWrite(data_ptr, length);
   return data_ptr;
 }
 void Pickle::TrimWriteData(int new_length) {
   DCHECK(variable_buffer_offset_ != 0);
   // Fetch the the variable buffer size
   int* cur_length = reinterpret_cast<int*>(
       reinterpret_cast<char*>(header_) + variable_buffer_offset_);
   if (new_length < 0 || new_length > *cur_length) {
     NOTREACHED() << "Invalid length in TrimWriteData.";
     return;
   }
   // Update the payload size and variable buffer size
   header_->payload_size -= (*cur_length - new_length);
   *cur_length = new_length;
 }
 bool Pickle::Resize(uint32_t new_capacity) {
   new_capacity = ConstantAligner<kPayloadUnit>::align(new_capacity);
   void* p = realloc(header_, new_capacity);
   if (!p)
     return false;
   header_ = reinterpret_cast<Header*>(p);
   capacity_ = new_capacity;
   return true;
 }
 // static
 const char* Pickle::FindNext(uint32_t header_size,
                              const char* start,
                              const char* end) {
   DCHECK(header_size == AlignInt(header_size));
   DCHECK(header_size <= static_cast<memberAlignmentType>(kPayloadUnit));
   const Header* hdr = reinterpret_cast<const Header*>(start);
   const char* payload_base = start + header_size;
   const char* payload_end = payload_base + hdr->payload_size;
   if (payload_end < payload_base)
     return NULL;
   return (payload_end > end) ? NULL : payload_end;
 }

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ipc/chromium/src/base/pickle.cc@6474c204b198 (annotated)

ipc/chromium/src/base/pickle.cc