extensions/common/value_counter.cc

   1 // Copyright 2014 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 "extensions/common/value_counter.h"
   6
   7 #include <algorithm>
   8
   9 #include "base/values.h"
  10
  11 namespace extensions {
  12
  13 struct ValueCounter::Entry {
  14   explicit Entry(scoped_ptr<base::Value> value)
  15       : value(value.Pass()), count(1) {}
  16
  17   scoped_ptr<base::Value> value;
  18   int count;
  19 };
  20
  21 ValueCounter::ValueCounter() {
  22 }
  23
  24 ValueCounter::~ValueCounter() {
  25 }
  26
  27 bool ValueCounter::Add(const base::Value& value) {
  28   for (Entry* entry : entries_) {
  29     if (entry->value->Equals(&value)) {
  30       ++entry->count;
  31       return false;
  32     }
  33   }
  34   entries_.push_back(new Entry(value.CreateDeepCopy()));
  35   return true;
  36 }
  37
  38 bool ValueCounter::Remove(const base::Value& value) {
  39   for (ScopedVector<Entry>::iterator it = entries_.begin();
  40        it != entries_.end(); ++it) {
  41     if ((*it)->value->Equals(&value)) {
  42       if (--(*it)->count == 0) {
  43         std::swap(*it, entries_.back());
  44         entries_.pop_back();
  45         return true;  // Removed the last entry.
  46       }
  47       return false;  // Removed, but no the last entry.
  48     }
  49   }
  50   return false;  // Nothing to remove.
  51 }
  52
  53 }  // namespace extensions