Add ContentSuggestionsCategoryFactory; Store categories as ints

components/ntp_snippets/content_suggestions_category_factory.cc

Index: components/ntp_snippets/content_suggestions_category_factory.cc
diff --git a/components/ntp_snippets/content_suggestions_category_factory.cc b/components/ntp_snippets/content_suggestions_category_factory.cc
new file mode 100644
index 0000000000000000000000000000000000000000..6410607af3c7e3fd8f551a532b4e3964fc88a3f9
--- /dev/null
+++ b/components/ntp_snippets/content_suggestions_category_factory.cc
@@ -0,0 +1,85 @@
+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "components/ntp_snippets/content_suggestions_category_factory.h"
+
+#include <algorithm>
+
+#include "base/logging.h"
+
+namespace ntp_snippets {
+
+ContentSuggestionsCategoryFactory::ContentSuggestionsCategoryFactory() {
+  // Add all local categories in a fixed order.
+  AddKnownCategory(KnownSuggestionsCategories::OFFLINE_PAGES);
+}
+
+ContentSuggestionsCategoryFactory::~ContentSuggestionsCategoryFactory() {}
+
+ContentSuggestionsCategory ContentSuggestionsCategoryFactory::FromKnownCategory(
+    KnownSuggestionsCategories known_category) {
+  if (known_category < KnownSuggestionsCategories::LOCAL_CATEGORIES_COUNT) {
+    // Local categories should have been added already.
+    DCHECK(CategoryExists(static_cast<int>(known_category)));
+  } else {
+    DCHECK_GT(known_category,
+              KnownSuggestionsCategories::REMOTE_CATEGORIES_OFFSET);
+  }
+  return InternalFromID(static_cast<int>(known_category));
+}
+
+ContentSuggestionsCategory
+ContentSuggestionsCategoryFactory::FromRemoteCategory(int remote_category) {
+  DCHECK_GT(remote_category, 0);
+  return InternalFromID(
+      static_cast<int>(KnownSuggestionsCategories::REMOTE_CATEGORIES_OFFSET) +
+      remote_category);
+}
+
+ContentSuggestionsCategory ContentSuggestionsCategoryFactory::FromIDValue(
+    int id) {
+  DCHECK_GE(id, 0);
+  DCHECK(id < static_cast<int>(
+                  KnownSuggestionsCategories::LOCAL_CATEGORIES_COUNT) ||
+         id > static_cast<int>(
+                  KnownSuggestionsCategories::REMOTE_CATEGORIES_OFFSET));
+  return InternalFromID(id);
+}
+
+bool ContentSuggestionsCategoryFactory::CompareCategories(
+    const ContentSuggestionsCategory& left,
+    const ContentSuggestionsCategory& right) const {
+  if (left == right)
+    return false;
+  return std::find(ordered_categories_.begin(), ordered_categories_.end(),
+                   left) < std::find(ordered_categories_.begin(),
+                                     ordered_categories_.end(), right);
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// Private methods
+
+bool ContentSuggestionsCategoryFactory::CategoryExists(int id) {
+  return std::find(ordered_categories_.begin(), ordered_categories_.end(),
+                   ContentSuggestionsCategory(id)) != ordered_categories_.end();
+}
+
+void ContentSuggestionsCategoryFactory::AddKnownCategory(
+    KnownSuggestionsCategories known_category) {
+  InternalFromID(static_cast<int>(known_category));
+}
+
+ContentSuggestionsCategory ContentSuggestionsCategoryFactory::InternalFromID(
+    int id) {
+  auto it = std::find(ordered_categories_.begin(), ordered_categories_.end(),
+                      ContentSuggestionsCategory(id));
+  if (it != ordered_categories_.end())
+    return *it;
+
+  ContentSuggestionsCategory category(id);
+  ordered_categories_.push_back(category);
+  return category;
+}
+
+}  // namespace ntp_snippets