Create ReadingListSuggestionsProvider

components/ntp_snippets/reading_list/reading_list_suggestions_provider.cc

+// Copyright 2017 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/reading_list/reading_list_suggestions_provider.h"
+
+#include <vector>
+
+#include "base/bind.h"
+#include "base/threading/thread_task_runner_handle.h"
+#include "components/ntp_snippets/category.h"
+#include "components/reading_list/core/reading_list_entry.h"
+#include "components/reading_list/core/reading_list_model.h"
+#include "components/strings/grit/components_strings.h"
+#include "ui/base/l10n/l10n_util.h"
+
+namespace ntp_snippets {
+
+ReadingListSuggestionsProvider::ReadingListSuggestionsProvider(
+    ContentSuggestionsProvider::Observer* observer,
+    ReadingListModel* reading_list_model)
+    : ContentSuggestionsProvider(observer),
+      category_status_(CategoryStatus::AVAILABLE_LOADING),
+      provided_category_(
+          Category::FromKnownCategory(KnownCategories::READING_LIST)),
+      reading_list_model_(reading_list_model) {
+  observer->OnCategoryStatusChanged(this, provided_category_, category_status_);
+  reading_list_model->AddObserver(this);
+  if (reading_list_model_->loaded()) {
+    FetchReadingListInternal();
+  }
+}
+
+ReadingListSuggestionsProvider::~ReadingListSuggestionsProvider() {
+  reading_list_model_->RemoveObserver(this);
+}
+
+CategoryStatus ReadingListSuggestionsProvider::GetCategoryStatus(
+    Category category) {
+  DCHECK_EQ(category, provided_category_);
+  return category_status_;
+}
+
+CategoryInfo ReadingListSuggestionsProvider::GetCategoryInfo(
+    Category category) {
+  DCHECK_EQ(category, provided_category_);
+
+  return CategoryInfo(l10n_util::GetStringUTF16(
+                          IDS_NTP_READING_LIST_SUGGESTIONS_SECTION_HEADER),
+                      ContentSuggestionsCardLayout::FULL_CARD,
+                      ContentSuggestionsAdditionalAction::VIEW_ALL,
+                      /*show_if_empty=*/false,
+                      l10n_util::GetStringUTF16(
+                          IDS_NTP_READING_LIST_SUGGESTIONS_SECTION_EMPTY));
+}
+
+void ReadingListSuggestionsProvider::DismissSuggestion(
+    const ContentSuggestion::ID& suggestion_id) {
+  // TODO(crbug.com/702241): Implement this method.
+}
+
+void ReadingListSuggestionsProvider::FetchSuggestionImage(
+    const ContentSuggestion::ID& suggestion_id,
+    const ImageFetchedCallback& callback) {
+  // TODO(crbug.com/702241): Implement this method.
+}
+
+void ReadingListSuggestionsProvider::Fetch(
+    const Category& category,
+    const std::set<std::string>& known_suggestion_ids,
+    const FetchDoneCallback& callback) {
+  LOG(DFATAL) << "ReadingListSuggestionsProvider has no |Fetch| functionality!";

[Bernhard Bauer, 2017/03/27 15:15:02]

DFATAL smells a bit like trying to handle a DCHECK failure, which is not
allowed, per
https://chromium.googlesource.com/chromium/src/+/master/styleguide/c++/c++.md....
If this method is genuinely not supposed to be called, just put NOTREACHED()
here and no production code.

[Marc Treib, 2017/03/27 15:19:29]

This is a pattern we have in all the providers - the intention was that we'd
notice if this ever happened, but we still don't crash prod binaries. The
"contract" that this is never called is quite far away, it essentially depends
on the UI doing the right thing.

All this clearly needs a redesign, but it's not a problem with this CL.

+  base::ThreadTaskRunnerHandle::Get()->PostTask(
+      FROM_HERE,
+      base::Bind(callback,
+                 Status(StatusCode::PERMANENT_ERROR,
+                        "ReadingListSuggestionsProvider has no |Fetch| "
+                        "functionality!"),
+                 base::Passed(std::vector<ContentSuggestion>())));
+}
+
+void ReadingListSuggestionsProvider::ClearHistory(
+    base::Time begin,
+    base::Time end,
+    const base::Callback<bool(const GURL& url)>& filter) {
+  // TODO(crbug.com/702241): Implement this method.
+}
+
+void ReadingListSuggestionsProvider::ClearCachedSuggestions(Category category) {
+  DCHECK_EQ(category, provided_category_);
+  // Ignored.
+}
+
+void ReadingListSuggestionsProvider::GetDismissedSuggestionsForDebugging(
+    Category category,
+    const DismissedSuggestionsCallback& callback) {
+  // TODO(crbug.com/702241): Implement this method.
+}
+void ReadingListSuggestionsProvider::ClearDismissedSuggestionsForDebugging(
+    Category category) {
+  // TODO(crbug.com/702241): Implement this method.
+}
+
+void ReadingListSuggestionsProvider::ReadingListModelLoaded(
+    const ReadingListModel* model) {
+  DCHECK(model == reading_list_model_);
+  FetchReadingListInternal();
+}
+
+void ReadingListSuggestionsProvider::FetchReadingListInternal() {
+  // TODO(crbug.com/702241): Implement this method.
+}
+
+}  // namespace ntp_snippets