values.h revision c407dc5cd9bdc5668497f21b26b09d988ab439de
1// Copyright (c) 2010 The Chromium Authors. All rights reserved. 2// Use of this source code is governed by a BSD-style license that can be 3// found in the LICENSE file. 4 5// This file specifies a recursive data storage class called Value 6// intended for storing setting and other persistable data. 7// It includes the ability to specify (recursive) lists and dictionaries, so 8// it's fairly expressive. However, the API is optimized for the common case, 9// namely storing a hierarchical tree of simple values. Given a 10// DictionaryValue root, you can easily do things like: 11// 12// root->SetString(L"global.pages.homepage", L"http://goateleporter.com"); 13// std::wstring homepage = L"http://google.com"; // default/fallback value 14// root->GetString(L"global.pages.homepage", &homepage); 15// 16// where "global" and "pages" are also DictionaryValues, and "homepage" 17// is a string setting. If some elements of the path didn't exist yet, 18// the SetString() method would create the missing elements and attach them 19// to root before attaching the homepage value. 20 21#ifndef BASE_VALUES_H_ 22#define BASE_VALUES_H_ 23 24#include <iterator> 25#include <map> 26#include <string> 27#include <vector> 28 29#include "base/basictypes.h" 30#include "base/string16.h" 31#include "build/build_config.h" 32 33class Value; 34class FundamentalValue; 35class StringValue; 36class BinaryValue; 37class DictionaryValue; 38class ListValue; 39 40typedef std::vector<Value*> ValueVector; 41typedef std::map<std::wstring, Value*> ValueMap; 42 43// The Value class is the base class for Values. A Value can be 44// instantiated via the Create*Value() factory methods, or by directly 45// creating instances of the subclasses. 46class Value { 47 public: 48 virtual ~Value(); 49 50 // Convenience methods for creating Value objects for various 51 // kinds of values without thinking about which class implements them. 52 // These can always be expected to return a valid Value*. 53 static Value* CreateNullValue(); 54 static Value* CreateBooleanValue(bool in_value); 55 static Value* CreateIntegerValue(int in_value); 56 static Value* CreateRealValue(double in_value); 57 static Value* CreateStringValue(const std::string& in_value); 58 static Value* CreateStringValue(const std::wstring& in_value); 59 static Value* CreateStringValueFromUTF16(const string16& in_value); 60 61 // This one can return NULL if the input isn't valid. If the return value 62 // is non-null, the new object has taken ownership of the buffer pointer. 63 static BinaryValue* CreateBinaryValue(char* buffer, size_t size); 64 65 typedef enum { 66 TYPE_NULL = 0, 67 TYPE_BOOLEAN, 68 TYPE_INTEGER, 69 TYPE_REAL, 70 TYPE_STRING, 71 TYPE_BINARY, 72 TYPE_DICTIONARY, 73 TYPE_LIST 74 } ValueType; 75 76 // Returns the type of the value stored by the current Value object. 77 // Each type will be implemented by only one subclass of Value, so it's 78 // safe to use the ValueType to determine whether you can cast from 79 // Value* to (Implementing Class)*. Also, a Value object never changes 80 // its type after construction. 81 ValueType GetType() const { return type_; } 82 83 // Returns true if the current object represents a given type. 84 bool IsType(ValueType type) const { return type == type_; } 85 86 // These methods allow the convenient retrieval of settings. 87 // If the current setting object can be converted into the given type, 88 // the value is returned through the |out_value| parameter and true is 89 // returned; otherwise, false is returned and |out_value| is unchanged. 90 virtual bool GetAsBoolean(bool* out_value) const; 91 virtual bool GetAsInteger(int* out_value) const; 92 virtual bool GetAsReal(double* out_value) const; 93 virtual bool GetAsString(std::string* out_value) const; 94 virtual bool GetAsString(std::wstring* out_value) const; 95 virtual bool GetAsUTF16(string16* out_value) const; 96 97 // This creates a deep copy of the entire Value tree, and returns a pointer 98 // to the copy. The caller gets ownership of the copy, of course. 99 virtual Value* DeepCopy() const; 100 101 // Compares if two Value objects have equal contents. 102 virtual bool Equals(const Value* other) const; 103 104 protected: 105 // This isn't safe for end-users (they should use the Create*Value() 106 // static methods above), but it's useful for subclasses. 107 explicit Value(ValueType type); 108 109 private: 110 Value(); 111 112 ValueType type_; 113 114 DISALLOW_COPY_AND_ASSIGN(Value); 115}; 116 117// FundamentalValue represents the simple fundamental types of values. 118class FundamentalValue : public Value { 119 public: 120 explicit FundamentalValue(bool in_value); 121 explicit FundamentalValue(int in_value); 122 explicit FundamentalValue(double in_value); 123 ~FundamentalValue(); 124 125 // Subclassed methods 126 virtual bool GetAsBoolean(bool* out_value) const; 127 virtual bool GetAsInteger(int* out_value) const; 128 virtual bool GetAsReal(double* out_value) const; 129 virtual Value* DeepCopy() const; 130 virtual bool Equals(const Value* other) const; 131 132 private: 133 union { 134 bool boolean_value_; 135 int integer_value_; 136 double real_value_; 137 }; 138 139 DISALLOW_COPY_AND_ASSIGN(FundamentalValue); 140}; 141 142class StringValue : public Value { 143 public: 144 // Initializes a StringValue with a UTF-8 narrow character string. 145 explicit StringValue(const std::string& in_value); 146 147 // Initializes a StringValue with a wide character string. 148 explicit StringValue(const std::wstring& in_value); 149 150#if !defined(WCHAR_T_IS_UTF16) 151 // Initializes a StringValue with a string16. 152 explicit StringValue(const string16& in_value); 153#endif 154 155 ~StringValue(); 156 157 // Subclassed methods 158 bool GetAsString(std::string* out_value) const; 159 bool GetAsString(std::wstring* out_value) const; 160 bool GetAsUTF16(string16* out_value) const; 161 Value* DeepCopy() const; 162 virtual bool Equals(const Value* other) const; 163 164 private: 165 std::string value_; 166 167 DISALLOW_COPY_AND_ASSIGN(StringValue); 168}; 169 170class BinaryValue: public Value { 171 public: 172 // Creates a Value to represent a binary buffer. The new object takes 173 // ownership of the pointer passed in, if successful. 174 // Returns NULL if buffer is NULL. 175 static BinaryValue* Create(char* buffer, size_t size); 176 177 // For situations where you want to keep ownership of your buffer, this 178 // factory method creates a new BinaryValue by copying the contents of the 179 // buffer that's passed in. 180 // Returns NULL if buffer is NULL. 181 static BinaryValue* CreateWithCopiedBuffer(const char* buffer, size_t size); 182 183 ~BinaryValue(); 184 185 // Subclassed methods 186 Value* DeepCopy() const; 187 virtual bool Equals(const Value* other) const; 188 189 size_t GetSize() const { return size_; } 190 char* GetBuffer() { return buffer_; } 191 const char* GetBuffer() const { return buffer_; } 192 193 private: 194 // Constructor is private so that only objects with valid buffer pointers 195 // and size values can be created. 196 BinaryValue(char* buffer, size_t size); 197 198 char* buffer_; 199 size_t size_; 200 201 DISALLOW_COPY_AND_ASSIGN(BinaryValue); 202}; 203 204class DictionaryValue : public Value { 205 public: 206 DictionaryValue(); 207 ~DictionaryValue(); 208 209 // Subclassed methods 210 Value* DeepCopy() const; 211 virtual bool Equals(const Value* other) const; 212 213 // Returns true if the current dictionary has a value for the given key. 214 bool HasKeyASCII(const std::string& key) const; 215 // Deprecated version of the above. TODO: add a string16 version for Unicode. 216 // http://code.google.com/p/chromium/issues/detail?id=23581 217 bool HasKey(const std::wstring& key) const; 218 219 // Returns the number of Values in this dictionary. 220 size_t size() const { return dictionary_.size(); } 221 222 // Returns whether the dictionary is empty. 223 bool empty() const { return dictionary_.empty(); } 224 225 // Clears any current contents of this dictionary. 226 void Clear(); 227 228 // Sets the Value associated with the given path starting from this object. 229 // A path has the form "<key>" or "<key>.<key>.[...]", where "." indexes 230 // into the next DictionaryValue down. Obviously, "." can't be used 231 // within a key, but there are no other restrictions on keys. 232 // If the key at any step of the way doesn't exist, or exists but isn't 233 // a DictionaryValue, a new DictionaryValue will be created and attached 234 // to the path in that location. 235 // Note that the dictionary takes ownership of the value referenced by 236 // |in_value|, and therefore |in_value| must be non-NULL. 237 void Set(const std::wstring& path, Value* in_value); 238 239 // Convenience forms of Set(). These methods will replace any existing 240 // value at that path, even if it has a different type. 241 void SetBoolean(const std::wstring& path, bool in_value); 242 void SetInteger(const std::wstring& path, int in_value); 243 void SetReal(const std::wstring& path, double in_value); 244 void SetString(const std::wstring& path, const std::string& in_value); 245 void SetString(const std::wstring& path, const std::wstring& in_value); 246 void SetStringFromUTF16(const std::wstring& path, const string16& in_value); 247 248 // Like Set(), but without special treatment of '.'. This allows e.g. URLs to 249 // be used as paths. 250 void SetWithoutPathExpansion(const std::wstring& key, Value* in_value); 251 252 // Gets the Value associated with the given path starting from this object. 253 // A path has the form "<key>" or "<key>.<key>.[...]", where "." indexes 254 // into the next DictionaryValue down. If the path can be resolved 255 // successfully, the value for the last key in the path will be returned 256 // through the |out_value| parameter, and the function will return true. 257 // Otherwise, it will return false and |out_value| will be untouched. 258 // Note that the dictionary always owns the value that's returned. 259 bool Get(const std::wstring& path, Value** out_value) const; 260 261 // These are convenience forms of Get(). The value will be retrieved 262 // and the return value will be true if the path is valid and the value at 263 // the end of the path can be returned in the form specified. 264 bool GetBoolean(const std::wstring& path, bool* out_value) const; 265 bool GetInteger(const std::wstring& path, int* out_value) const; 266 bool GetReal(const std::wstring& path, double* out_value) const; 267 bool GetString(const std::string& path, string16* out_value) const; 268 bool GetStringASCII(const std::string& path, std::string* out_value) const; 269 // TODO: deprecate wstring accessors. 270 // http://code.google.com/p/chromium/issues/detail?id=23581 271 bool GetString(const std::wstring& path, std::string* out_value) const; 272 bool GetString(const std::wstring& path, std::wstring* out_value) const; 273 bool GetStringAsUTF16(const std::wstring& path, string16* out_value) const; 274 bool GetBinary(const std::wstring& path, BinaryValue** out_value) const; 275 bool GetDictionary(const std::wstring& path, 276 DictionaryValue** out_value) const; 277 bool GetList(const std::wstring& path, ListValue** out_value) const; 278 279 // Like Get(), but without special treatment of '.'. This allows e.g. URLs to 280 // be used as paths. 281 bool GetWithoutPathExpansion(const std::wstring& key, 282 Value** out_value) const; 283 bool GetIntegerWithoutPathExpansion(const std::wstring& path, 284 int* out_value) const; 285 bool GetStringWithoutPathExpansion(const std::wstring& path, 286 std::string* out_value) const; 287 bool GetStringWithoutPathExpansion(const std::wstring& path, 288 std::wstring* out_value) const; 289 bool GetStringAsUTF16WithoutPathExpansion(const std::wstring& path, 290 string16* out_value) const; 291 bool GetDictionaryWithoutPathExpansion(const std::wstring& path, 292 DictionaryValue** out_value) const; 293 bool GetListWithoutPathExpansion(const std::wstring& path, 294 ListValue** out_value) const; 295 296 // Removes the Value with the specified path from this dictionary (or one 297 // of its child dictionaries, if the path is more than just a local key). 298 // If |out_value| is non-NULL, the removed Value AND ITS OWNERSHIP will be 299 // passed out via out_value. If |out_value| is NULL, the removed value will 300 // be deleted. This method returns true if |path| is a valid path; otherwise 301 // it will return false and the DictionaryValue object will be unchanged. 302 bool Remove(const std::wstring& path, Value** out_value); 303 304 // Like Remove(), but without special treatment of '.'. This allows e.g. URLs 305 // to be used as paths. 306 bool RemoveWithoutPathExpansion(const std::wstring& key, Value** out_value); 307 308 // Makes a copy of |this| but doesn't include empty dictionaries and lists in 309 // the copy. This never returns NULL, even if |this| itself is empty. 310 DictionaryValue* DeepCopyWithoutEmptyChildren(); 311 312 // Merge a given dictionary into this dictionary. This is done recursively, 313 // i.e. any subdictionaries will be merged as well. In case of key collisions, 314 // the passed in dictionary takes precedence and data already present will be 315 // replaced. 316 void MergeDictionary(const DictionaryValue* dictionary); 317 318 // This class provides an iterator for the keys in the dictionary. 319 // It can't be used to modify the dictionary. 320 // 321 // YOU SHOULD ALWAYS USE THE XXXWithoutPathExpansion() APIs WITH THESE, NOT 322 // THE NORMAL XXX() APIs. This makes sure things will work correctly if any 323 // keys have '.'s in them. 324 class key_iterator 325 : private std::iterator<std::input_iterator_tag, const std::wstring> { 326 public: 327 explicit key_iterator(ValueMap::const_iterator itr) { itr_ = itr; } 328 key_iterator operator++() { 329 ++itr_; 330 return *this; 331 } 332 const std::wstring& operator*() { return itr_->first; } 333 bool operator!=(const key_iterator& other) { return itr_ != other.itr_; } 334 bool operator==(const key_iterator& other) { return itr_ == other.itr_; } 335 336 private: 337 ValueMap::const_iterator itr_; 338 }; 339 340 key_iterator begin_keys() const { return key_iterator(dictionary_.begin()); } 341 key_iterator end_keys() const { return key_iterator(dictionary_.end()); } 342 343 private: 344 ValueMap dictionary_; 345 346 DISALLOW_COPY_AND_ASSIGN(DictionaryValue); 347}; 348 349// This type of Value represents a list of other Value values. 350class ListValue : public Value { 351 public: 352 ListValue(); 353 ~ListValue(); 354 355 // Subclassed methods 356 Value* DeepCopy() const; 357 virtual bool Equals(const Value* other) const; 358 359 // Clears the contents of this ListValue 360 void Clear(); 361 362 // Returns the number of Values in this list. 363 size_t GetSize() const { return list_.size(); } 364 365 // Returns whether the list is empty. 366 bool empty() const { return list_.empty(); } 367 368 // Sets the list item at the given index to be the Value specified by 369 // the value given. If the index beyond the current end of the list, null 370 // Values will be used to pad out the list. 371 // Returns true if successful, or false if the index was negative or 372 // the value is a null pointer. 373 bool Set(size_t index, Value* in_value); 374 375 // Gets the Value at the given index. Modifies |out_value| (and returns true) 376 // only if the index falls within the current list range. 377 // Note that the list always owns the Value passed out via |out_value|. 378 bool Get(size_t index, Value** out_value) const; 379 380 // Convenience forms of Get(). Modifies |out_value| (and returns true) 381 // only if the index is valid and the Value at that index can be returned 382 // in the specified form. 383 bool GetBoolean(size_t index, bool* out_value) const; 384 bool GetInteger(size_t index, int* out_value) const; 385 bool GetReal(size_t index, double* out_value) const; 386 bool GetString(size_t index, std::string* out_value) const; 387 bool GetString(size_t index, std::wstring* out_value) const; 388 bool GetStringAsUTF16(size_t index, string16* out_value) const; 389 bool GetBinary(size_t index, BinaryValue** out_value) const; 390 bool GetDictionary(size_t index, DictionaryValue** out_value) const; 391 bool GetList(size_t index, ListValue** out_value) const; 392 393 // Removes the Value with the specified index from this list. 394 // If |out_value| is non-NULL, the removed Value AND ITS OWNERSHIP will be 395 // passed out via |out_value|. If |out_value| is NULL, the removed value will 396 // be deleted. This method returns true if |index| is valid; otherwise 397 // it will return false and the ListValue object will be unchanged. 398 bool Remove(size_t index, Value** out_value); 399 400 // Removes the first instance of |value| found in the list, if any, and 401 // deletes it. Returns the index that it was located at (-1 for not present). 402 int Remove(const Value& value); 403 404 // Appends a Value to the end of the list. 405 void Append(Value* in_value); 406 407 // Appends a Value if it's not already present. 408 // Returns true if successful, or false if the value was already present. 409 bool AppendIfNotPresent(Value* in_value); 410 411 // Insert a Value at index. 412 // Returns true if successful, or false if the index was out of range. 413 bool Insert(size_t index, Value* in_value); 414 415 // Iteration 416 typedef ValueVector::iterator iterator; 417 typedef ValueVector::const_iterator const_iterator; 418 419 ListValue::iterator begin() { return list_.begin(); } 420 ListValue::iterator end() { return list_.end(); } 421 422 ListValue::const_iterator begin() const { return list_.begin(); } 423 ListValue::const_iterator end() const { return list_.end(); } 424 425 private: 426 ValueVector list_; 427 428 DISALLOW_COPY_AND_ASSIGN(ListValue); 429}; 430 431// This interface is implemented by classes that know how to serialize and 432// deserialize Value objects. 433class ValueSerializer { 434 public: 435 virtual ~ValueSerializer(); 436 437 virtual bool Serialize(const Value& root) = 0; 438 439 // This method deserializes the subclass-specific format into a Value object. 440 // If the return value is non-NULL, the caller takes ownership of returned 441 // Value. If the return value is NULL, and if error_code is non-NULL, 442 // error_code will be set with the underlying error. 443 // If |error_message| is non-null, it will be filled in with a formatted 444 // error message including the location of the error if appropriate. 445 virtual Value* Deserialize(int* error_code, std::string* error_str) = 0; 446}; 447 448#endif // BASE_VALUES_H_ 449