1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/ipc/chromium/src/base/pickle.h Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,287 @@
1.4 +// Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
1.5 +// Use of this source code is governed by a BSD-style license that can be
1.6 +// found in the LICENSE file.
1.7 +
1.8 +#ifndef BASE_PICKLE_H__
1.9 +#define BASE_PICKLE_H__
1.10 +
1.11 +#include <string>
1.12 +
1.13 +#include "base/basictypes.h"
1.14 +#include "base/logging.h"
1.15 +#include "base/string16.h"
1.16 +
1.17 +// This class provides facilities for basic binary value packing and unpacking.
1.18 +//
1.19 +// The Pickle class supports appending primitive values (ints, strings, etc.)
1.20 +// to a pickle instance. The Pickle instance grows its internal memory buffer
1.21 +// dynamically to hold the sequence of primitive values. The internal memory
1.22 +// buffer is exposed as the "data" of the Pickle. This "data" can be passed
1.23 +// to a Pickle object to initialize it for reading.
1.24 +//
1.25 +// When reading from a Pickle object, it is important for the consumer to know
1.26 +// what value types to read and in what order to read them as the Pickle does
1.27 +// not keep track of the type of data written to it.
1.28 +//
1.29 +// The Pickle's data has a header which contains the size of the Pickle's
1.30 +// payload. It can optionally support additional space in the header. That
1.31 +// space is controlled by the header_size parameter passed to the Pickle
1.32 +// constructor.
1.33 +//
1.34 +class Pickle {
1.35 + public:
1.36 + ~Pickle();
1.37 +
1.38 + // Initialize a Pickle object using the default header size.
1.39 + Pickle();
1.40 +
1.41 + // Initialize a Pickle object with the specified header size in bytes, which
1.42 + // must be greater-than-or-equal-to sizeof(Pickle::Header). The header size
1.43 + // will be rounded up to ensure that the header size is 32bit-aligned.
1.44 + explicit Pickle(int header_size);
1.45 +
1.46 + // Initializes a Pickle from a const block of data. The data is not copied;
1.47 + // instead the data is merely referenced by this Pickle. Only const methods
1.48 + // should be used on the Pickle when initialized this way. The header
1.49 + // padding size is deduced from the data length.
1.50 + Pickle(const char* data, int data_len);
1.51 +
1.52 + // Initializes a Pickle as a deep copy of another Pickle.
1.53 + Pickle(const Pickle& other);
1.54 +
1.55 + // Performs a deep copy.
1.56 + Pickle& operator=(const Pickle& other);
1.57 +
1.58 + // Returns the size of the Pickle's data.
1.59 + int size() const { return static_cast<int>(header_size_ +
1.60 + header_->payload_size); }
1.61 +
1.62 + // Returns the data for this Pickle.
1.63 + const void* data() const { return header_; }
1.64 +
1.65 + // Methods for reading the payload of the Pickle. To read from the start of
1.66 + // the Pickle, initialize *iter to NULL. If successful, these methods return
1.67 + // true. Otherwise, false is returned to indicate that the result could not
1.68 + // be extracted.
1.69 + bool ReadBool(void** iter, bool* result) const;
1.70 + bool ReadInt16(void** iter, int16_t* result) const;
1.71 + bool ReadUInt16(void** iter, uint16_t* result) const;
1.72 + bool ReadShort(void** iter, short* result) const;
1.73 + bool ReadInt(void** iter, int* result) const;
1.74 + bool ReadLong(void** iter, long* result) const;
1.75 + bool ReadULong(void** iter, unsigned long* result) const;
1.76 + bool ReadSize(void** iter, size_t* result) const;
1.77 + bool ReadInt32(void** iter, int32_t* result) const;
1.78 + bool ReadUInt32(void** iter, uint32_t* result) const;
1.79 + bool ReadInt64(void** iter, int64_t* result) const;
1.80 + bool ReadUInt64(void** iter, uint64_t* result) const;
1.81 + bool ReadDouble(void** iter, double* result) const;
1.82 + bool ReadIntPtr(void** iter, intptr_t* result) const;
1.83 + bool ReadUnsignedChar(void** iter, unsigned char* result) const;
1.84 + bool ReadString(void** iter, std::string* result) const;
1.85 + bool ReadWString(void** iter, std::wstring* result) const;
1.86 + bool ReadString16(void** iter, string16* result) const;
1.87 + bool ReadData(void** iter, const char** data, int* length) const;
1.88 + bool ReadBytes(void** iter, const char** data, int length,
1.89 + uint32_t alignment = sizeof(memberAlignmentType)) const;
1.90 +
1.91 + // Safer version of ReadInt() checks for the result not being negative.
1.92 + // Use it for reading the object sizes.
1.93 + bool ReadLength(void** iter, int* result) const;
1.94 +
1.95 + // Methods for adding to the payload of the Pickle. These values are
1.96 + // appended to the end of the Pickle's payload. When reading values from a
1.97 + // Pickle, it is important to read them in the order in which they were added
1.98 + // to the Pickle.
1.99 + bool WriteBool(bool value) {
1.100 + return WriteInt(value ? 1 : 0);
1.101 + }
1.102 + bool WriteInt16(int16_t value) {
1.103 + return WriteBytes(&value, sizeof(value));
1.104 + }
1.105 + bool WriteUInt16(uint16_t value) {
1.106 + return WriteBytes(&value, sizeof(value));
1.107 + }
1.108 + bool WriteInt(int value) {
1.109 + return WriteBytes(&value, sizeof(value));
1.110 + }
1.111 + bool WriteLong(long value) {
1.112 + // Always written as a 64-bit value since the size for this type can
1.113 + // differ between architectures.
1.114 + return WriteInt64(int64_t(value));
1.115 + }
1.116 + bool WriteULong(unsigned long value) {
1.117 + // Always written as a 64-bit value since the size for this type can
1.118 + // differ between architectures.
1.119 + return WriteUInt64(uint64_t(value));
1.120 + }
1.121 + bool WriteSize(size_t value) {
1.122 + // Always written as a 64-bit value since the size for this type can
1.123 + // differ between architectures.
1.124 + return WriteUInt64(uint64_t(value));
1.125 + }
1.126 + bool WriteInt32(int32_t value) {
1.127 + return WriteBytes(&value, sizeof(value));
1.128 + }
1.129 + bool WriteUInt32(uint32_t value) {
1.130 + return WriteBytes(&value, sizeof(value));
1.131 + }
1.132 + bool WriteInt64(int64_t value) {
1.133 + return WriteBytes(&value, sizeof(value));
1.134 + }
1.135 + bool WriteUInt64(uint64_t value) {
1.136 + return WriteBytes(&value, sizeof(value));
1.137 + }
1.138 + bool WriteDouble(double value) {
1.139 + return WriteBytes(&value, sizeof(value));
1.140 + }
1.141 + bool WriteIntPtr(intptr_t value) {
1.142 + // Always written as a 64-bit value since the size for this type can
1.143 + // differ between architectures.
1.144 + return WriteInt64(int64_t(value));
1.145 + }
1.146 + bool WriteUnsignedChar(unsigned char value) {
1.147 + return WriteBytes(&value, sizeof(value));
1.148 + }
1.149 + bool WriteString(const std::string& value);
1.150 + bool WriteWString(const std::wstring& value);
1.151 + bool WriteString16(const string16& value);
1.152 + bool WriteData(const char* data, int length);
1.153 + bool WriteBytes(const void* data, int data_len,
1.154 + uint32_t alignment = sizeof(memberAlignmentType));
1.155 +
1.156 + // Same as WriteData, but allows the caller to write directly into the
1.157 + // Pickle. This saves a copy in cases where the data is not already
1.158 + // available in a buffer. The caller should take care to not write more
1.159 + // than the length it declares it will. Use ReadData to get the data.
1.160 + // Returns NULL on failure.
1.161 + //
1.162 + // The returned pointer will only be valid until the next write operation
1.163 + // on this Pickle.
1.164 + char* BeginWriteData(int length);
1.165 +
1.166 + // For Pickles which contain variable length buffers (e.g. those created
1.167 + // with BeginWriteData), the Pickle can
1.168 + // be 'trimmed' if the amount of data required is less than originally
1.169 + // requested. For example, you may have created a buffer with 10K of data,
1.170 + // but decided to only fill 10 bytes of that data. Use this function
1.171 + // to trim the buffer so that we don't send 9990 bytes of unused data.
1.172 + // You cannot increase the size of the variable buffer; only shrink it.
1.173 + // This function assumes that the length of the variable buffer has
1.174 + // not been changed.
1.175 + void TrimWriteData(int length);
1.176 +
1.177 + void EndRead(void* iter) const {
1.178 + DCHECK(iter == end_of_payload());
1.179 + }
1.180 +
1.181 + // Payload follows after allocation of Header (header size is customizable).
1.182 + struct Header {
1.183 + uint32_t payload_size; // Specifies the size of the payload.
1.184 + };
1.185 +
1.186 + // Returns the header, cast to a user-specified type T. The type T must be a
1.187 + // subclass of Header and its size must correspond to the header_size passed
1.188 + // to the Pickle constructor.
1.189 + template <class T>
1.190 + T* headerT() {
1.191 + DCHECK(sizeof(T) == header_size_);
1.192 + return static_cast<T*>(header_);
1.193 + }
1.194 + template <class T>
1.195 + const T* headerT() const {
1.196 + DCHECK(sizeof(T) == header_size_);
1.197 + return static_cast<const T*>(header_);
1.198 + }
1.199 +
1.200 + // Returns true if the given iterator could point to data with the given
1.201 + // length. If there is no room for the given data before the end of the
1.202 + // payload, returns false.
1.203 + bool IteratorHasRoomFor(const void* iter, int len) const {
1.204 + if ((len < 0) || (iter < header_) || iter > end_of_payload())
1.205 + return false;
1.206 + const char* end_of_region = reinterpret_cast<const char*>(iter) + len;
1.207 + // Watch out for overflow in pointer calculation, which wraps.
1.208 + return (iter <= end_of_region) && (end_of_region <= end_of_payload());
1.209 + }
1.210 +
1.211 + typedef uint32_t memberAlignmentType;
1.212 +
1.213 + protected:
1.214 + uint32_t payload_size() const { return header_->payload_size; }
1.215 +
1.216 + char* payload() {
1.217 + return reinterpret_cast<char*>(header_) + header_size_;
1.218 + }
1.219 + const char* payload() const {
1.220 + return reinterpret_cast<const char*>(header_) + header_size_;
1.221 + }
1.222 +
1.223 + // Returns the address of the byte immediately following the currently valid
1.224 + // header + payload.
1.225 + char* end_of_payload() {
1.226 + return payload() + payload_size();
1.227 + }
1.228 + const char* end_of_payload() const {
1.229 + return payload() + payload_size();
1.230 + }
1.231 +
1.232 + uint32_t capacity() const {
1.233 + return capacity_;
1.234 + }
1.235 +
1.236 + // Resizes the buffer for use when writing the specified amount of data. The
1.237 + // location that the data should be written at is returned, or NULL if there
1.238 + // was an error. Call EndWrite with the returned offset and the given length
1.239 + // to pad out for the next write.
1.240 + char* BeginWrite(uint32_t length, uint32_t alignment);
1.241 +
1.242 + // Completes the write operation by padding the data with NULL bytes until it
1.243 + // is padded. Should be paired with BeginWrite, but it does not necessarily
1.244 + // have to be called after the data is written.
1.245 + void EndWrite(char* dest, int length);
1.246 +
1.247 + // Resize the capacity, note that the input value should include the size of
1.248 + // the header: new_capacity = sizeof(Header) + desired_payload_capacity.
1.249 + // A realloc() failure will cause a Resize failure... and caller should check
1.250 + // the return result for true (i.e., successful resizing).
1.251 + bool Resize(uint32_t new_capacity);
1.252 +
1.253 + // Round 'bytes' up to the next multiple of 'alignment'. 'alignment' must be
1.254 + // a power of 2.
1.255 + template<uint32_t alignment> struct ConstantAligner {
1.256 + static uint32_t align(int bytes) {
1.257 + static_assert((alignment & (alignment - 1)) == 0,
1.258 + "alignment must be a power of two");
1.259 + return (bytes + (alignment - 1)) & ~static_cast<uint32_t>(alignment - 1);
1.260 + }
1.261 + };
1.262 +
1.263 + static uint32_t AlignInt(int bytes) {
1.264 + return ConstantAligner<sizeof(memberAlignmentType)>::align(bytes);
1.265 + }
1.266 +
1.267 + // Moves the iterator by the given number of bytes, making sure it is aligned.
1.268 + // Pointer (iterator) is NOT aligned, but the change in the pointer
1.269 + // is guaranteed to be a multiple of sizeof(memberAlignmentType).
1.270 + static void UpdateIter(void** iter, int bytes) {
1.271 + *iter = static_cast<char*>(*iter) + AlignInt(bytes);
1.272 + }
1.273 +
1.274 + // Find the end of the pickled data that starts at range_start. Returns NULL
1.275 + // if the entire Pickle is not found in the given data range.
1.276 + static const char* FindNext(uint32_t header_size,
1.277 + const char* range_start,
1.278 + const char* range_end);
1.279 +
1.280 + // The allocation granularity of the payload.
1.281 + static const int kPayloadUnit;
1.282 +
1.283 + private:
1.284 + Header* header_;
1.285 + uint32_t header_size_;
1.286 + uint32_t capacity_;
1.287 + uint32_t variable_buffer_offset_;
1.288 +};
1.289 +
1.290 +#endif // BASE_PICKLE_H__
