content/common/indexed_db/indexed_db_key.cc

   1 // Copyright (c) 2012 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 #include "content/common/indexed_db/indexed_db_key.h"
   6
   7 #include <string>
   8 #include "base/logging.h"
   9
  10 namespace content {
  11
  12 using blink::WebIDBKey;
  13 using blink::WebIDBKeyType;
  14 using blink::WebIDBKeyTypeArray;
  15 using blink::WebIDBKeyTypeBinary;
  16 using blink::WebIDBKeyTypeDate;
  17 using blink::WebIDBKeyTypeInvalid;
  18 using blink::WebIDBKeyTypeMin;
  19 using blink::WebIDBKeyTypeNull;
  20 using blink::WebIDBKeyTypeNumber;
  21 using blink::WebIDBKeyTypeString;
  22
  23 namespace {
  24
  25 // Very rough estimate of minimum key size overhead.
  26 const size_t kOverheadSize = 16;
  27
  28 static size_t CalculateArraySize(const IndexedDBKey::KeyArray& keys) {
  29   size_t size(0);
  30   for (size_t i = 0; i < keys.size(); ++i)
  31     size += keys[i].size_estimate();
  32   return size;
  33 }
  34
  35 template<typename T>
  36 int Compare(const T& a, const T& b) {
  37   // Using '<' for both comparisons here is as generic as possible (for e.g.
  38   // objects which only define operator<() and not operator>() or operator==())
  39   // and also allows e.g. floating point NaNs to compare equal.
  40   if (a < b)
  41     return -1;
  42   return (b < a) ? 1 : 0;
  43 }
  44
  45 template <typename T>
  46 static IndexedDBKey::KeyArray CopyKeyArray(const T& array) {
  47   IndexedDBKey::KeyArray result;
  48   result.reserve(array.size());
  49   for (size_t i = 0; i < array.size(); ++i) {
  50     result.push_back(IndexedDBKey(array[i]));
  51   }
  52   return result;
  53 }
  54
  55 }  // namespace
  56
  57 IndexedDBKey::IndexedDBKey()
  58     : type_(WebIDBKeyTypeNull),
  59       date_(0),
  60       number_(0),
  61       size_estimate_(kOverheadSize) {}
  62
  63 IndexedDBKey::IndexedDBKey(WebIDBKeyType type)
  64     : type_(type), date_(0), number_(0), size_estimate_(kOverheadSize) {
  65   DCHECK(type == WebIDBKeyTypeNull || type == WebIDBKeyTypeInvalid);
  66 }
  67
  68 IndexedDBKey::IndexedDBKey(double number, WebIDBKeyType type)
  69     : type_(type),
  70       date_(number),
  71       number_(number),
  72       size_estimate_(kOverheadSize + sizeof(number)) {
  73   DCHECK(type == WebIDBKeyTypeNumber || type == WebIDBKeyTypeDate);
  74 }
  75
  76 IndexedDBKey::IndexedDBKey(const KeyArray& array)
  77     : type_(WebIDBKeyTypeArray),
  78       array_(CopyKeyArray(array)),
  79       date_(0),
  80       number_(0),
  81       size_estimate_(kOverheadSize + CalculateArraySize(array)) {}
  82
  83 IndexedDBKey::IndexedDBKey(const std::string& binary)
  84     : type_(WebIDBKeyTypeBinary),
  85       binary_(binary),
  86       size_estimate_(kOverheadSize +
  87                      (binary.length() * sizeof(std::string::value_type))) {}
  88
  89 IndexedDBKey::IndexedDBKey(const base::string16& string)
  90     : type_(WebIDBKeyTypeString),
  91       string_(string),
  92       size_estimate_(kOverheadSize +
  93                      (string.length() * sizeof(base::string16::value_type))) {}
  94
  95 IndexedDBKey::~IndexedDBKey() {}
  96
  97 bool IndexedDBKey::IsValid() const {
  98   if (type_ == WebIDBKeyTypeInvalid || type_ == WebIDBKeyTypeNull)
  99     return false;
 100
 101   if (type_ == WebIDBKeyTypeArray) {
 102     for (size_t i = 0; i < array_.size(); i++) {
 103       if (!array_[i].IsValid())
 104         return false;
 105     }
 106   }
 107
 108   return true;
 109 }
 110
 111 bool IndexedDBKey::IsLessThan(const IndexedDBKey& other) const {
 112   return CompareTo(other) < 0;
 113 }
 114
 115 bool IndexedDBKey::Equals(const IndexedDBKey& other) const {
 116   return !CompareTo(other);
 117 }
 118
 119 int IndexedDBKey::CompareTo(const IndexedDBKey& other) const {
 120   DCHECK(IsValid());
 121   DCHECK(other.IsValid());
 122   if (type_ != other.type_)
 123     return type_ > other.type_ ? -1 : 1;
 124
 125   switch (type_) {
 126     case WebIDBKeyTypeArray:
 127       for (size_t i = 0; i < array_.size() && i < other.array_.size(); ++i) {
 128         int result = array_[i].CompareTo(other.array_[i]);
 129         if (result != 0)
 130           return result;
 131       }
 132       return Compare(array_.size(), other.array_.size());
 133     case WebIDBKeyTypeBinary:
 134       return binary_.compare(other.binary_);
 135     case WebIDBKeyTypeString:
 136       return string_.compare(other.string_);
 137     case WebIDBKeyTypeDate:
 138       return Compare(date_, other.date_);
 139     case WebIDBKeyTypeNumber:
 140       return Compare(number_, other.number_);
 141     case WebIDBKeyTypeInvalid:
 142     case WebIDBKeyTypeNull:
 143     case WebIDBKeyTypeMin:
 144     default:
 145       NOTREACHED();
 146       return 0;
 147   }
 148 }
 149
 150 }  // namespace content