mukesh agrawal | 292dc0f | 2012-01-26 18:02:46 -0800 | [diff] [blame] | 1 | // Copyright (c) 2012 The Chromium OS Authors. All rights reserved. |
Chris Masone | 3bd3c8c | 2011-06-13 08:20:26 -0700 | [diff] [blame] | 2 | // Use of this source code is governed by a BSD-style license that can be |
| 3 | // found in the LICENSE file. |
| 4 | |
| 5 | #ifndef SHILL_PROPERTY_ACCESSOR_ |
| 6 | #define SHILL_PROPERTY_ACCESSOR_ |
| 7 | |
| 8 | #include <base/basictypes.h> |
Chris Masone | 27bf103 | 2011-06-28 17:02:01 -0700 | [diff] [blame] | 9 | #include <base/logging.h> |
Gaurav Shah | 1b7a616 | 2011-11-09 11:41:01 -0800 | [diff] [blame] | 10 | #include <gtest/gtest_prod.h> // for FRIEND_TEST. |
Chris Masone | 3bd3c8c | 2011-06-13 08:20:26 -0700 | [diff] [blame] | 11 | |
| 12 | #include "shill/accessor_interface.h" |
mukesh agrawal | ffa3d04 | 2011-10-06 15:26:10 -0700 | [diff] [blame] | 13 | #include "shill/error.h" |
Chris Masone | 3bd3c8c | 2011-06-13 08:20:26 -0700 | [diff] [blame] | 14 | |
| 15 | namespace shill { |
| 16 | |
| 17 | // Templated implementations of AccessorInterface<>. |
mukesh agrawal | 292dc0f | 2012-01-26 18:02:46 -0800 | [diff] [blame] | 18 | // |
| 19 | // PropertyAccessor<>, ConstPropertyAccessor<>, and |
| 20 | // WriteOnlyPropertyAccessor<> provide R/W, R/O, and W/O access |
| 21 | // (respectively) to the value pointed to by |property|. |
| 22 | // |
| 23 | // This allows a class to easily map strings to member variables, so that |
Chris Masone | 3bd3c8c | 2011-06-13 08:20:26 -0700 | [diff] [blame] | 24 | // pieces of state stored in the class can be queried or updated by name. |
| 25 | // |
| 26 | // bool foo = true; |
| 27 | // map<string, BoolAccessor> accessors; |
| 28 | // accessors["foo"] = BoolAccessor(new PropertyAccessor<bool>(&foo)); |
| 29 | // bool new_foo = accessors["foo"]->Get(); // new_foo == true |
| 30 | // accessors["foo"]->Set(false); // returns true, because setting is allowed. |
| 31 | // // foo == false, new_foo == true |
| 32 | // new_foo = accessors["foo"]->Get(); // new_foo == false |
mukesh agrawal | 292dc0f | 2012-01-26 18:02:46 -0800 | [diff] [blame] | 33 | // // Clear resets |foo| to its value when the PropertyAccessor was created. |
| 34 | // accessors["foo"]->Clear(); // foo == true |
Chris Masone | 3bd3c8c | 2011-06-13 08:20:26 -0700 | [diff] [blame] | 35 | template <class T> |
| 36 | class PropertyAccessor : public AccessorInterface<T> { |
| 37 | public: |
mukesh agrawal | 292dc0f | 2012-01-26 18:02:46 -0800 | [diff] [blame] | 38 | explicit PropertyAccessor(T *property) |
| 39 | : property_(property), default_value_(*property) { |
Chris Masone | 3bd3c8c | 2011-06-13 08:20:26 -0700 | [diff] [blame] | 40 | DCHECK(property); |
| 41 | } |
| 42 | virtual ~PropertyAccessor() {} |
| 43 | |
mukesh agrawal | 292dc0f | 2012-01-26 18:02:46 -0800 | [diff] [blame] | 44 | void Clear(Error *error) { Set(default_value_, error); } |
Gaurav Shah | 1b7a616 | 2011-11-09 11:41:01 -0800 | [diff] [blame] | 45 | T Get(Error */*error*/) { return *property_; } |
mukesh agrawal | ffa3d04 | 2011-10-06 15:26:10 -0700 | [diff] [blame] | 46 | void Set(const T &value, Error */*error*/) { |
Chris Masone | 3bd3c8c | 2011-06-13 08:20:26 -0700 | [diff] [blame] | 47 | *property_ = value; |
Chris Masone | 3bd3c8c | 2011-06-13 08:20:26 -0700 | [diff] [blame] | 48 | } |
| 49 | |
| 50 | private: |
| 51 | T * const property_; |
mukesh agrawal | 292dc0f | 2012-01-26 18:02:46 -0800 | [diff] [blame] | 52 | const T default_value_; |
Chris Masone | 3bd3c8c | 2011-06-13 08:20:26 -0700 | [diff] [blame] | 53 | DISALLOW_COPY_AND_ASSIGN(PropertyAccessor); |
| 54 | }; |
| 55 | |
| 56 | template <class T> |
| 57 | class ConstPropertyAccessor : public AccessorInterface<T> { |
| 58 | public: |
| 59 | explicit ConstPropertyAccessor(const T *property) : property_(property) { |
| 60 | DCHECK(property); |
| 61 | } |
| 62 | virtual ~ConstPropertyAccessor() {} |
| 63 | |
mukesh agrawal | 292dc0f | 2012-01-26 18:02:46 -0800 | [diff] [blame] | 64 | void Clear(Error *error) { |
| 65 | // TODO(quiche): check if this is the right error. |
| 66 | // (maybe Error::kInvalidProperty instead?) |
| 67 | error->Populate(Error::kInvalidArguments, "Property is read-only"); |
| 68 | } |
Gaurav Shah | 1b7a616 | 2011-11-09 11:41:01 -0800 | [diff] [blame] | 69 | T Get(Error */*error*/) { return *property_; } |
mukesh agrawal | ffa3d04 | 2011-10-06 15:26:10 -0700 | [diff] [blame] | 70 | void Set(const T &/*value*/, Error *error) { |
| 71 | // TODO(quiche): check if this is the right error. |
| 72 | // (maybe Error::kPermissionDenied instead?) |
| 73 | error->Populate(Error::kInvalidArguments, "Property is read-only"); |
| 74 | } |
Chris Masone | 3bd3c8c | 2011-06-13 08:20:26 -0700 | [diff] [blame] | 75 | |
| 76 | private: |
| 77 | const T * const property_; |
| 78 | DISALLOW_COPY_AND_ASSIGN(ConstPropertyAccessor); |
| 79 | }; |
| 80 | |
Gaurav Shah | 1b7a616 | 2011-11-09 11:41:01 -0800 | [diff] [blame] | 81 | template <class T> |
| 82 | class WriteOnlyPropertyAccessor : public AccessorInterface<T> { |
| 83 | public: |
mukesh agrawal | 292dc0f | 2012-01-26 18:02:46 -0800 | [diff] [blame] | 84 | explicit WriteOnlyPropertyAccessor(T *property) |
| 85 | : property_(property), default_value_(*property) { |
Gaurav Shah | 1b7a616 | 2011-11-09 11:41:01 -0800 | [diff] [blame] | 86 | DCHECK(property); |
| 87 | } |
| 88 | virtual ~WriteOnlyPropertyAccessor() {} |
| 89 | |
mukesh agrawal | 292dc0f | 2012-01-26 18:02:46 -0800 | [diff] [blame] | 90 | void Clear(Error *error) { Set(default_value_, error); } |
Gaurav Shah | 1b7a616 | 2011-11-09 11:41:01 -0800 | [diff] [blame] | 91 | T Get(Error *error) { |
| 92 | error->Populate(Error::kPermissionDenied, "Property is write-only"); |
| 93 | return T(); |
| 94 | } |
| 95 | void Set(const T &value, Error */*error*/) { |
| 96 | *property_ = value; |
| 97 | } |
| 98 | |
| 99 | private: |
| 100 | FRIEND_TEST(PropertyAccessorTest, SignedIntCorrectness); |
| 101 | FRIEND_TEST(PropertyAccessorTest, UnsignedIntCorrectness); |
| 102 | FRIEND_TEST(PropertyAccessorTest, StringCorrectness); |
| 103 | |
| 104 | T * const property_; |
mukesh agrawal | 292dc0f | 2012-01-26 18:02:46 -0800 | [diff] [blame] | 105 | const T default_value_; |
Gaurav Shah | 1b7a616 | 2011-11-09 11:41:01 -0800 | [diff] [blame] | 106 | DISALLOW_COPY_AND_ASSIGN(WriteOnlyPropertyAccessor); |
| 107 | }; |
| 108 | |
Chris Masone | 3bd3c8c | 2011-06-13 08:20:26 -0700 | [diff] [blame] | 109 | // CustomAccessor<> allows custom getter and setter methods to be provided. |
mukesh agrawal | 292dc0f | 2012-01-26 18:02:46 -0800 | [diff] [blame] | 110 | // Thus, if the state to be returned is to be derived on-demand, or if |
| 111 | // setting the property requires validation, we can still fit it into the |
| 112 | // AccessorInterface<> framework. |
| 113 | // |
| 114 | // If the property is write-only, use CustomWriteOnlyAccessor instead. |
Chris Masone | 3bd3c8c | 2011-06-13 08:20:26 -0700 | [diff] [blame] | 115 | template<class C, class T> |
| 116 | class CustomAccessor : public AccessorInterface<T> { |
| 117 | public: |
| 118 | // |target| is the object on which to call the methods |getter| and |setter| |
| 119 | // |setter| is allowed to be NULL, in which case we will simply reject |
| 120 | // attempts to set via the accessor. |
| 121 | // It is an error to pass NULL for either of the other two arguments. |
mukesh agrawal | ffa3d04 | 2011-10-06 15:26:10 -0700 | [diff] [blame] | 122 | CustomAccessor(C *target, |
Hristo Stefanov | ed2c28c | 2011-11-29 15:37:30 -0800 | [diff] [blame] | 123 | T(C::*getter)(Error *error), |
| 124 | void(C::*setter)(const T &value, Error *error)) |
Chris Masone | 3bd3c8c | 2011-06-13 08:20:26 -0700 | [diff] [blame] | 125 | : target_(target), |
mukesh agrawal | 292dc0f | 2012-01-26 18:02:46 -0800 | [diff] [blame] | 126 | default_value_(), |
Chris Masone | 3bd3c8c | 2011-06-13 08:20:26 -0700 | [diff] [blame] | 127 | getter_(getter), |
| 128 | setter_(setter) { |
| 129 | DCHECK(target); |
mukesh agrawal | 292dc0f | 2012-01-26 18:02:46 -0800 | [diff] [blame] | 130 | DCHECK(getter); // otherwise, use CustomWriteOnlyAccessor |
| 131 | if (setter_) { |
| 132 | Error e; |
| 133 | default_value_ = Get(&e); |
| 134 | } |
Chris Masone | 3bd3c8c | 2011-06-13 08:20:26 -0700 | [diff] [blame] | 135 | } |
| 136 | virtual ~CustomAccessor() {} |
| 137 | |
mukesh agrawal | 292dc0f | 2012-01-26 18:02:46 -0800 | [diff] [blame] | 138 | void Clear(Error *error) { Set(default_value_, error); } |
Gaurav Shah | 1b7a616 | 2011-11-09 11:41:01 -0800 | [diff] [blame] | 139 | T Get(Error *error) { |
mukesh agrawal | 292dc0f | 2012-01-26 18:02:46 -0800 | [diff] [blame] | 140 | return (target_->*getter_)(error); |
Gaurav Shah | 1b7a616 | 2011-11-09 11:41:01 -0800 | [diff] [blame] | 141 | } |
mukesh agrawal | ffa3d04 | 2011-10-06 15:26:10 -0700 | [diff] [blame] | 142 | void Set(const T &value, Error *error) { |
| 143 | if (setter_) { |
| 144 | (target_->*setter_)(value, error); |
| 145 | } else { |
| 146 | error->Populate(Error::kInvalidArguments, "Property is read-only"); |
| 147 | } |
| 148 | } |
Chris Masone | 3bd3c8c | 2011-06-13 08:20:26 -0700 | [diff] [blame] | 149 | |
| 150 | private: |
mukesh agrawal | 292dc0f | 2012-01-26 18:02:46 -0800 | [diff] [blame] | 151 | C *const target_; |
| 152 | // |default_value_| is non-const because it can't be initialized in |
| 153 | // the initializer list. |
| 154 | T default_value_; |
| 155 | T(C::*const getter_)(Error *error); |
| 156 | void(C::*const setter_)(const T &value, Error *error); |
Chris Masone | 3bd3c8c | 2011-06-13 08:20:26 -0700 | [diff] [blame] | 157 | DISALLOW_COPY_AND_ASSIGN(CustomAccessor); |
| 158 | }; |
| 159 | |
mukesh agrawal | 292dc0f | 2012-01-26 18:02:46 -0800 | [diff] [blame] | 160 | // CustomWriteOnlyAccessor<> allows a custom writer method to be provided. |
| 161 | // Get returns an error automatically. Clear resets the value to a |
| 162 | // default value. |
| 163 | template<class C, class T> |
| 164 | class CustomWriteOnlyAccessor : public AccessorInterface<T> { |
| 165 | public: |
| 166 | // |target| is the object on which to call |setter| and |clearer|. |
| 167 | // |
| 168 | // |target| and |setter| must be non-NULL. |
| 169 | // |
| 170 | // Either |clearer| or |default_value|, but not both, must be non-NULL. |
| 171 | // Whichever is non-NULL is used to clear the property. |
| 172 | CustomWriteOnlyAccessor(C *target, |
| 173 | void(C::*setter)(const T &value, Error *error), |
| 174 | void(C::*clearer)(Error *error), |
| 175 | const T *default_value) |
| 176 | : target_(target), |
| 177 | setter_(setter), |
| 178 | clearer_(clearer), |
| 179 | default_value_() { |
| 180 | DCHECK(target); |
| 181 | DCHECK(setter); |
| 182 | DCHECK(clearer || default_value); |
| 183 | DCHECK(!clearer || !default_value); |
| 184 | if (default_value) { |
| 185 | default_value_ = *default_value; |
| 186 | } |
| 187 | } |
| 188 | virtual ~CustomWriteOnlyAccessor() {} |
| 189 | |
| 190 | void Clear(Error *error) { |
| 191 | if (clearer_) { |
| 192 | (target_->*clearer_)(error); |
| 193 | } else { |
| 194 | Set(default_value_, error); |
| 195 | } |
| 196 | } |
| 197 | T Get(Error *error) { |
| 198 | error->Populate(Error::kPermissionDenied, "Property is write-only"); |
| 199 | return T(); |
| 200 | } |
| 201 | void Set(const T &value, Error *error) { |
| 202 | (target_->*setter_)(value, error); |
| 203 | } |
| 204 | |
| 205 | private: |
| 206 | C *const target_; |
| 207 | void(C::*const setter_)(const T &value, Error *error); |
| 208 | void(C::*const clearer_)(Error *error); |
| 209 | // |default_value_| is non-const because it can't be initialized in |
| 210 | // the initializer list. |
| 211 | T default_value_; |
| 212 | DISALLOW_COPY_AND_ASSIGN(CustomWriteOnlyAccessor); |
| 213 | }; |
| 214 | |
Paul Stewart | a61593e | 2012-03-23 13:06:21 -0700 | [diff] [blame] | 215 | // CustomMappedAccessor<> passes an argument to the getter and setter |
| 216 | // so that a generic method can be used, for example one that accesses the |
| 217 | // property in a map. |
| 218 | template<class C, class T, class A> |
| 219 | class CustomMappedAccessor : public AccessorInterface<T> { |
| 220 | public: |
| 221 | // |target| is the object on which to call the methods |getter| and |setter|. |
| 222 | // |setter| is allowed to be NULL, in which case we will simply reject |
| 223 | // attempts to set via the accessor. |
| 224 | // |argument| is passed to the getter and setter methods to disambiguate |
| 225 | // between different properties in |target|. |
| 226 | // It is an error to pass NULL for any of |target|, |clearer| or |getter|. |
| 227 | CustomMappedAccessor(C *target, |
| 228 | void(C::*clearer)(const A &argument, Error *error), |
| 229 | T(C::*getter)(const A &argument, Error *error), |
| 230 | void(C::*setter)(const T &value, const A &argument, |
| 231 | Error *error), |
| 232 | const A &argument) |
| 233 | : target_(target), |
| 234 | clearer_(clearer), |
| 235 | getter_(getter), |
| 236 | setter_(setter), |
| 237 | argument_(argument) { |
| 238 | DCHECK(clearer); |
| 239 | DCHECK(target); |
| 240 | DCHECK(getter); |
| 241 | } |
| 242 | virtual ~CustomMappedAccessor() {} |
| 243 | |
| 244 | void Clear(Error *error) { |
| 245 | (target_->*clearer_)(argument_, error); |
| 246 | } |
| 247 | T Get(Error *error) { |
| 248 | return (target_->*getter_)(argument_, error); |
| 249 | } |
| 250 | void Set(const T &value, Error *error) { |
| 251 | if (setter_) { |
| 252 | (target_->*setter_)(value, argument_, error); |
| 253 | } else { |
| 254 | error->Populate(Error::kInvalidArguments, "Property is read-only"); |
| 255 | } |
| 256 | } |
| 257 | |
| 258 | private: |
| 259 | C *const target_; |
| 260 | void(C::*const clearer_)(const A &argument, Error *error); |
| 261 | T(C::*const getter_)(const A &argument, Error *error); |
| 262 | void(C::*const setter_)(const T &value, const A &argument, Error *error); |
| 263 | A argument_; |
| 264 | DISALLOW_COPY_AND_ASSIGN(CustomMappedAccessor); |
| 265 | }; |
| 266 | |
Chris Masone | 3bd3c8c | 2011-06-13 08:20:26 -0700 | [diff] [blame] | 267 | } // namespace shill |
| 268 | |
| 269 | #endif // SHILL_PROPERTY_ACCESSOR_ |