dom/indexedDB/Key.h

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #ifndef mozilla_dom_indexeddb_key_h__
   8 #define mozilla_dom_indexeddb_key_h__
   9
  10 #include "mozilla/dom/indexedDB/IndexedDatabase.h"
  11
  12 #include "mozIStorageStatement.h"
  13
  14 #include "js/Value.h"
  15
  16 namespace IPC {
  17 template <typename T> struct ParamTraits;
  18 } // namespace IPC
  19
  20 BEGIN_INDEXEDDB_NAMESPACE
  21
  22 class Key
  23 {
  24   friend struct IPC::ParamTraits<Key>;
  25
  26 public:
  27   Key()
  28   {
  29     Unset();
  30   }
  31
  32   Key& operator=(const nsAString& aString)
  33   {
  34     SetFromString(aString);
  35     return *this;
  36   }
  37
  38   Key& operator=(int64_t aInt)
  39   {
  40     SetFromInteger(aInt);
  41     return *this;
  42   }
  43
  44   bool operator==(const Key& aOther) const
  45   {
  46     NS_ASSERTION(!mBuffer.IsVoid() && !aOther.mBuffer.IsVoid(),
  47                  "Don't compare unset keys!");
  48
  49     return mBuffer.Equals(aOther.mBuffer);
  50   }
  51
  52   bool operator!=(const Key& aOther) const
  53   {
  54     NS_ASSERTION(!mBuffer.IsVoid() && !aOther.mBuffer.IsVoid(),
  55                  "Don't compare unset keys!");
  56
  57     return !mBuffer.Equals(aOther.mBuffer);
  58   }
  59
  60   bool operator<(const Key& aOther) const
  61   {
  62     NS_ASSERTION(!mBuffer.IsVoid() && !aOther.mBuffer.IsVoid(),
  63                  "Don't compare unset keys!");
  64
  65     return Compare(mBuffer, aOther.mBuffer) < 0;
  66   }
  67
  68   bool operator>(const Key& aOther) const
  69   {
  70     NS_ASSERTION(!mBuffer.IsVoid() && !aOther.mBuffer.IsVoid(),
  71                  "Don't compare unset keys!");
  72
  73     return Compare(mBuffer, aOther.mBuffer) > 0;
  74   }
  75
  76   bool operator<=(const Key& aOther) const
  77   {
  78     NS_ASSERTION(!mBuffer.IsVoid() && !aOther.mBuffer.IsVoid(),
  79                  "Don't compare unset keys!");
  80
  81     return Compare(mBuffer, aOther.mBuffer) <= 0;
  82   }
  83
  84   bool operator>=(const Key& aOther) const
  85   {
  86     NS_ASSERTION(!mBuffer.IsVoid() && !aOther.mBuffer.IsVoid(),
  87                  "Don't compare unset keys!");
  88
  89     return Compare(mBuffer, aOther.mBuffer) >= 0;
  90   }
  91
  92   void
  93   Unset()
  94   {
  95     mBuffer.SetIsVoid(true);
  96   }
  97
  98   bool IsUnset() const
  99   {
 100     return mBuffer.IsVoid();
 101   }
 102
 103   bool IsFloat() const
 104   {
 105     return !IsUnset() && mBuffer.First() == eFloat;
 106   }
 107
 108   bool IsDate() const
 109   {
 110     return !IsUnset() && mBuffer.First() == eDate;
 111   }
 112
 113   bool IsString() const
 114   {
 115     return !IsUnset() && mBuffer.First() == eString;
 116   }
 117
 118   bool IsArray() const
 119   {
 120     return !IsUnset() && mBuffer.First() >= eArray;
 121   }
 122
 123   double ToFloat() const
 124   {
 125     NS_ASSERTION(IsFloat(), "Why'd you call this?");
 126     const unsigned char* pos = BufferStart();
 127     double res = DecodeNumber(pos, BufferEnd());
 128     NS_ASSERTION(pos >= BufferEnd(), "Should consume whole buffer");
 129     return res;
 130   }
 131
 132   double ToDateMsec() const
 133   {
 134     NS_ASSERTION(IsDate(), "Why'd you call this?");
 135     const unsigned char* pos = BufferStart();
 136     double res = DecodeNumber(pos, BufferEnd());
 137     NS_ASSERTION(pos >= BufferEnd(), "Should consume whole buffer");
 138     return res;
 139   }
 140
 141   void ToString(nsString& aString) const
 142   {
 143     NS_ASSERTION(IsString(), "Why'd you call this?");
 144     const unsigned char* pos = BufferStart();
 145     DecodeString(pos, BufferEnd(), aString);
 146     NS_ASSERTION(pos >= BufferEnd(), "Should consume whole buffer");
 147   }
 148
 149   void SetFromString(const nsAString& aString)
 150   {
 151     mBuffer.Truncate();
 152     EncodeString(aString, 0);
 153     TrimBuffer();
 154   }
 155
 156   void SetFromInteger(int64_t aInt)
 157   {
 158     mBuffer.Truncate();
 159     EncodeNumber(double(aInt), eFloat);
 160     TrimBuffer();
 161   }
 162
 163   nsresult SetFromJSVal(JSContext* aCx,
 164                         JS::Handle<JS::Value> aVal)
 165   {
 166     mBuffer.Truncate();
 167
 168     if (aVal.isNull() || aVal.isUndefined()) {
 169       Unset();
 170       return NS_OK;
 171     }
 172
 173     nsresult rv = EncodeJSVal(aCx, aVal, 0);
 174     if (NS_FAILED(rv)) {
 175       Unset();
 176       return rv;
 177     }
 178     TrimBuffer();
 179
 180     return NS_OK;
 181   }
 182
 183   nsresult ToJSVal(JSContext* aCx,
 184                    JS::MutableHandle<JS::Value> aVal) const
 185   {
 186     if (IsUnset()) {
 187       aVal.setUndefined();
 188       return NS_OK;
 189     }
 190
 191     const unsigned char* pos = BufferStart();
 192     nsresult rv = DecodeJSVal(pos, BufferEnd(), aCx, 0, aVal);
 193     NS_ENSURE_SUCCESS(rv, rv);
 194
 195     NS_ASSERTION(pos >= BufferEnd(),
 196                  "Didn't consume whole buffer");
 197
 198     return NS_OK;
 199   }
 200
 201   nsresult ToJSVal(JSContext* aCx,
 202                    JS::Heap<JS::Value>& aVal) const
 203   {
 204     JS::Rooted<JS::Value> value(aCx);
 205     nsresult rv = ToJSVal(aCx, &value);
 206     if (NS_SUCCEEDED(rv)) {
 207       aVal = value;
 208     }
 209     return rv;
 210   }
 211
 212   nsresult AppendItem(JSContext* aCx,
 213                       bool aFirstOfArray,
 214                       JS::Handle<JS::Value> aVal)
 215   {
 216     nsresult rv = EncodeJSVal(aCx, aVal, aFirstOfArray ? eMaxType : 0);
 217     if (NS_FAILED(rv)) {
 218       Unset();
 219       return rv;
 220     }
 221
 222     return NS_OK;
 223   }
 224
 225   void FinishArray()
 226   {
 227     TrimBuffer();
 228   }
 229
 230   const nsCString& GetBuffer() const
 231   {
 232     return mBuffer;
 233   }
 234
 235   nsresult BindToStatement(mozIStorageStatement* aStatement,
 236                            const nsACString& aParamName) const
 237   {
 238     nsresult rv = aStatement->BindBlobByName(aParamName,
 239       reinterpret_cast<const uint8_t*>(mBuffer.get()), mBuffer.Length());
 240
 241     return NS_SUCCEEDED(rv) ? NS_OK : NS_ERROR_DOM_INDEXEDDB_UNKNOWN_ERR;
 242   }
 243
 244   nsresult SetFromStatement(mozIStorageStatement* aStatement,
 245                             uint32_t aIndex)
 246   {
 247     uint8_t* data;
 248     uint32_t dataLength = 0;
 249
 250     nsresult rv = aStatement->GetBlob(aIndex, &dataLength, &data);
 251     NS_ENSURE_SUCCESS(rv, NS_ERROR_DOM_INDEXEDDB_UNKNOWN_ERR);
 252
 253     mBuffer.Adopt(
 254       reinterpret_cast<char*>(const_cast<uint8_t*>(data)), dataLength);
 255
 256     return NS_OK;
 257   }
 258
 259   static
 260   int16_t CompareKeys(Key& aFirst, Key& aSecond)
 261   {
 262     int32_t result = Compare(aFirst.mBuffer, aSecond.mBuffer);
 263
 264     if (result < 0) {
 265       return -1;
 266     }
 267
 268     if (result > 0) {
 269       return 1;
 270     }
 271
 272     return 0;
 273   }
 274
 275 private:
 276   const unsigned char* BufferStart() const
 277   {
 278     return reinterpret_cast<const unsigned char*>(mBuffer.BeginReading());
 279   }
 280
 281   const unsigned char* BufferEnd() const
 282   {
 283     return reinterpret_cast<const unsigned char*>(mBuffer.EndReading());
 284   }
 285
 286   enum {
 287     eTerminator = 0,
 288     eFloat = 1,
 289     eDate = 2,
 290     eString = 3,
 291     eArray = 4,
 292     eMaxType = eArray
 293   };
 294
 295   // Encoding helper. Trims trailing zeros off of mBuffer as a post-processing
 296   // step.
 297   void TrimBuffer()
 298   {
 299     const char* end = mBuffer.EndReading() - 1;
 300     while (!*end) {
 301       --end;
 302     }
 303
 304     mBuffer.Truncate(end + 1 - mBuffer.BeginReading());
 305   }
 306
 307   // Encoding functions. These append the encoded value to the end of mBuffer
 308   inline nsresult EncodeJSVal(JSContext* aCx, JS::Handle<JS::Value> aVal,
 309                               uint8_t aTypeOffset)
 310   {
 311     return EncodeJSValInternal(aCx, aVal, aTypeOffset, 0);
 312   }
 313   void EncodeString(const nsAString& aString, uint8_t aTypeOffset);
 314   void EncodeNumber(double aFloat, uint8_t aType);
 315
 316   // Decoding functions. aPos points into mBuffer and is adjusted to point
 317   // past the consumed value.
 318   static inline nsresult DecodeJSVal(const unsigned char*& aPos,
 319                                      const unsigned char* aEnd, JSContext* aCx,
 320                                      uint8_t aTypeOffset, JS::MutableHandle<JS::Value> aVal)
 321   {
 322     return DecodeJSValInternal(aPos, aEnd, aCx, aTypeOffset, aVal, 0);
 323   }
 324
 325   static void DecodeString(const unsigned char*& aPos,
 326                            const unsigned char* aEnd,
 327                            nsString& aString);
 328   static double DecodeNumber(const unsigned char*& aPos,
 329                              const unsigned char* aEnd);
 330
 331   nsCString mBuffer;
 332
 333 private:
 334   nsresult EncodeJSValInternal(JSContext* aCx, JS::Handle<JS::Value> aVal,
 335                                uint8_t aTypeOffset, uint16_t aRecursionDepth);
 336
 337   static nsresult DecodeJSValInternal(const unsigned char*& aPos,
 338                                       const unsigned char* aEnd,
 339                                       JSContext* aCx, uint8_t aTypeOffset,
 340                                       JS::MutableHandle<JS::Value> aVal, uint16_t aRecursionDepth);
 341 };
 342
 343 END_INDEXEDDB_NAMESPACE
 344
 345 #endif /* mozilla_dom_indexeddb_key_h__ */