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Diffstat (limited to 'base/pickle.cc')
-rw-r--r-- | base/pickle.cc | 449 |
1 files changed, 449 insertions, 0 deletions
diff --git a/base/pickle.cc b/base/pickle.cc new file mode 100644 index 000000000000..f42f249bb274 --- /dev/null +++ b/base/pickle.cc @@ -0,0 +1,449 @@ +// Copyright (c) 2011 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 <stdlib.h> + +#include <algorithm> // for max() +#include <limits> + +//------------------------------------------------------------------------------ + +// static +const int Pickle::kPayloadUnit = 64; + +// We mark a read only pickle with a special capacity_. +static const size_t kCapacityReadOnly = std::numeric_limits<size_t>::max(); + +// Payload is uint32 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, sizeof(uint32))), + capacity_(0), + variable_buffer_offset_(0) { + DCHECK_GE(static_cast<size_t>(header_size), sizeof(Header)); + DCHECK_LE(header_size, kPayloadUnit); + Resize(kPayloadUnit); + header_->payload_size = 0; +} + +Pickle::Pickle(const char* data, int data_len) + : header_(reinterpret_cast<Header*>(const_cast<char*>(data))), + header_size_(0), + capacity_(kCapacityReadOnly), + variable_buffer_offset_(0) +{ + + if (data_len >= static_cast<int>(sizeof(Header))) + { + header_size_ = data_len - header_->payload_size; + } + + if (header_size_ > static_cast<unsigned int>(data_len)) + { + header_size_ = 0; + } + + + if (header_size_ != AlignInt(header_size_, sizeof(uint32))) + { + header_size_ = 0; + } + + + // If there is anything wrong with the data, we're not going to use it. + if (!header_size_) + header_ = NULL; +} + +Pickle::Pickle(const Pickle& other) + : header_(NULL), + header_size_(other.header_size_), + capacity_(0), + variable_buffer_offset_(other.variable_buffer_offset_) { + size_t payload_size = header_size_ + other.header_->payload_size; + bool resized = Resize(payload_size); + CHECK(resized); // Realloc failed. + memcpy(header_, other.header_, payload_size); +} + +Pickle::~Pickle() { + if (capacity_ != kCapacityReadOnly) + free(header_); +} + +Pickle& Pickle::operator=(const Pickle& other) { + if (this == &other) { + NOTREACHED(); + return *this; + } + if (capacity_ == kCapacityReadOnly) { + header_ = NULL; + capacity_ = 0; + } + if (header_size_ != other.header_size_) { + free(header_); + header_ = NULL; + header_size_ = other.header_size_; + } + bool resized = Resize(other.header_size_ + other.header_->payload_size); + CHECK(resized); // Realloc failed. + memcpy(header_, other.header_, + other.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::ReadInt(void** iter, int* result) const { + DCHECK(iter); + if (!*iter) + *iter = const_cast<char*>(payload()); + + if (!IteratorHasRoomFor(*iter, sizeof(*result))) + return false; + + // TODO(jar): http://crbug.com/13108 Pickle should be cleaned up, and not + // dependent on alignment. + // Next line is otherwise the same as: memcpy(result, *iter, sizeof(*result)); + *result = *reinterpret_cast<int*>(*iter); + + UpdateIter(iter, sizeof(*result)); + return true; +} + +bool Pickle::ReadLong(void** iter, long* result) const { + DCHECK(iter); + if (!*iter) + *iter = const_cast<char*>(payload()); + + if (!IteratorHasRoomFor(*iter, sizeof(*result))) + return false; + + // TODO(jar): http://crbug.com/13108 Pickle should be cleaned up, and not + // dependent on alignment. + memcpy(result, *iter, sizeof(*result)); + + UpdateIter(iter, sizeof(*result)); + return true; +} + +bool Pickle::ReadSize(void** iter, size_t* result) const { + DCHECK(iter); + if (!*iter) + *iter = const_cast<char*>(payload()); + + if (!IteratorHasRoomFor(*iter, sizeof(*result))) + return false; + + // TODO(jar): http://crbug.com/13108 Pickle should be cleaned up, and not + // dependent on alignment. + // Next line is otherwise the same as: memcpy(result, *iter, sizeof(*result)); + *result = *reinterpret_cast<size_t*>(*iter); + + UpdateIter(iter, sizeof(*result)); + return true; +} + +bool Pickle::ReadUInt16(void** iter, uint16* result) const { + DCHECK(iter); + if (!*iter) + *iter = const_cast<char*>(payload()); + + if (!IteratorHasRoomFor(*iter, sizeof(*result))) + return false; + + memcpy(result, *iter, sizeof(*result)); + + UpdateIter(iter, sizeof(*result)); + return true; +} + +bool Pickle::ReadUInt32(void** iter, uint32* result) const { + DCHECK(iter); + if (!*iter) + *iter = const_cast<char*>(payload()); + + if (!IteratorHasRoomFor(*iter, sizeof(*result))) + return false; + + memcpy(result, *iter, sizeof(*result)); + + UpdateIter(iter, sizeof(*result)); + return true; +} + +bool Pickle::ReadInt64(void** iter, int64* result) const { + DCHECK(iter); + if (!*iter) + *iter = const_cast<char*>(payload()); + + if (!IteratorHasRoomFor(*iter, sizeof(*result))) + return false; + + memcpy(result, *iter, sizeof(*result)); + + UpdateIter(iter, sizeof(*result)); + return true; +} + +bool Pickle::ReadUInt64(void** iter, uint64* result) const { + DCHECK(iter); + if (!*iter) + *iter = const_cast<char*>(payload()); + + if (!IteratorHasRoomFor(*iter, sizeof(*result))) + return false; + + memcpy(result, *iter, sizeof(*result)); + + UpdateIter(iter, sizeof(*result)); + return true; +} + + +bool Pickle::ReadString(void** iter, std::string* result) const { + DCHECK(iter); + + 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); + + int len; + if (!ReadLength(iter, &len)) + return false; + // Avoid integer overflow. + if (len > INT_MAX / static_cast<int>(sizeof(wchar_t))) + 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); + + int len; + if (!ReadLength(iter, &len)) + return false; + if (!IteratorHasRoomFor(*iter, len * sizeof(char16))) + return false; + + char16* chars = reinterpret_cast<char16*>(*iter); + result->assign(chars, len); + + UpdateIter(iter, len * sizeof(char16)); + return true; +} +*/ + +bool Pickle::ReadData(void** iter, const char** data, int* length) const { + DCHECK(iter); + DCHECK(data); + DCHECK(length); + *length = 0; + *data = 0; + + if (!ReadLength(iter, length)) + return false; + + return ReadBytes(iter, data, *length); +} + +bool Pickle::ReadBytes(void** iter, const char** data, int length) const { + DCHECK(iter); + DCHECK(data); + *data = 0; + if (!*iter) + *iter = const_cast<char*>(payload()); + + if (!IteratorHasRoomFor(*iter, length)) + return false; + + *data = reinterpret_cast<const char*>(*iter); + + UpdateIter(iter, length); + return true; +} + +bool Pickle::ReadLength(void** iter, int* result) const { + if (!ReadInt(iter, result)) + return false; + return ((*result) >= 0); +} + + +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 length >= 0 && WriteInt(length) && WriteBytes(data, length); +} + +bool Pickle::WriteBytes(const void* data, int data_len) { + DCHECK_NE(kCapacityReadOnly, capacity_) << "oops: pickle is readonly"; + + char* dest = BeginWrite(data_len); + if (!dest) + return false; + + memcpy(dest, data, data_len); + + EndWrite(dest, data_len); + return true; +} + +char* Pickle::BeginWriteData(int length) { + DCHECK_EQ(variable_buffer_offset_, 0U) << + "There can only be one variable buffer in a Pickle"; + + if (length < 0 || !WriteInt(length)) + return NULL; + + char *data_ptr = BeginWrite(length); + 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_NE(variable_buffer_offset_, 0U); + + // 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; +} + +char* Pickle::BeginWrite(size_t length) { + // write at a uint32-aligned offset from the beginning of the header + size_t offset = AlignInt(header_->payload_size, sizeof(uint32)); + + size_t new_size = offset + length; + size_t needed_size = header_size_ + new_size; + if (needed_size > capacity_ && !Resize(std::max(capacity_ * 2, needed_size))) + return NULL; + +#ifdef ARCH_CPU_64_BITS + DCHECK_LE(length, std::numeric_limits<uint32>::max()); +#endif + + header_->payload_size = static_cast<uint32>(new_size); + return payload() + offset; +} + +void Pickle::EndWrite(char* dest, int length) { + // Zero-pad to keep tools like purify from complaining about uninitialized + // memory. + if (length % sizeof(uint32)) + memset(dest + length, 0, sizeof(uint32) - (length % sizeof(uint32))); +} + +bool Pickle::Resize(size_t new_capacity) { + new_capacity = AlignInt(new_capacity, kPayloadUnit); + + CHECK_NE(capacity_, kCapacityReadOnly); + 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(size_t header_size, + const char* start, + const char* end) { + DCHECK_EQ(header_size, AlignInt(header_size, sizeof(uint32))); + DCHECK_LE(header_size, static_cast<size_t>(kPayloadUnit)); + + if (static_cast<size_t>(end - start) < sizeof(Header)) + return NULL; + + 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; +} |