[Offline Pages] Updated clearing logic in storage manager.

components/offline_pages/offline_page_storage_manager.cc

 // 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/offline_pages/offline_page_storage_manager.h"
 
 #include <algorithm>
 
 #include "base/bind.h"
 #include "base/time/clock.h"
 #include "base/time/default_clock.h"
-#include "base/time/time.h"
 #include "components/offline_pages/client_policy_controller.h"
 #include "components/offline_pages/offline_page_client_policy.h"
 #include "components/offline_pages/offline_page_item.h"
-#include "components/offline_pages/offline_page_types.h"
 
 namespace offline_pages {
 
 OfflinePageStorageManager::OfflinePageStorageManager(
     Client* client,
-    ClientPolicyController* policy_controller)
+    ClientPolicyController* policy_controller,
+    ArchiveManager* archive_manager)
     : client_(client),
       policy_controller_(policy_controller),
+      archive_manager_(archive_manager),
       in_progress_(false),
       clock_(new base::DefaultClock()),
       weak_ptr_factory_(this) {}
 
 OfflinePageStorageManager::~OfflinePageStorageManager() {}
 
 void OfflinePageStorageManager::ClearPagesIfNeeded(
-    const ClearPageCallback& callback) {
-  if (!ShouldClearPages())
+    const ClearPagesCallback& callback) {
+  if (in_progress_)
     return;
   in_progress_ = true;
-  client_->GetAllPages(base::Bind(&OfflinePageStorageManager::ClearExpiredPages,
-                                  weak_ptr_factory_.GetWeakPtr(), callback));
-}
-
-void OfflinePageStorageManager::ClearExpiredPages(
-    const ClearPageCallback& callback,
-    const MultipleOfflinePageItemResult& pages) {
-  DCHECK(in_progress_);
-  std::vector<int64_t> offline_ids;
-  GetExpiredPageIds(pages, offline_ids);
-  client_->DeletePagesByOfflineId(
-      offline_ids,
-      base::Bind(&OfflinePageStorageManager::OnExpiredPagesDeleted,
-                 weak_ptr_factory_.GetWeakPtr(), callback, offline_ids.size()));
+  archive_manager_->GetStorageStats(
+      base::Bind(&OfflinePageStorageManager::OnGetStorageStatsDone,
+                 weak_ptr_factory_.GetWeakPtr(), callback));
 }
 
 void OfflinePageStorageManager::SetClockForTesting(
     std::unique_ptr<base::Clock> clock) {
   clock_ = std::move(clock);
 }
 
+void OfflinePageStorageManager::OnGetStorageStatsDone(
+    const ClearPagesCallback& callback,
+    const ArchiveManager::StorageStats& stats) {
+  DCHECK(in_progress_);
+  ClearMode mode = ShouldClearPages(stats);
+  if (mode == ClearMode::NOT_NEEDED) {
+    in_progress_ = false;
+    last_clear_time_ = clock_->Now();
+    callback.Run(0, ClearStorageResult::UNNECESSARY);
+    return;
+  }
+  client_->GetAllPages(base::Bind(&OfflinePageStorageManager::OnGetAllPagesDone,
+                                  weak_ptr_factory_.GetWeakPtr(), callback,
+                                  stats));
+}
+
+void OfflinePageStorageManager::OnGetAllPagesDone(
+    const ClearPagesCallback& callback,
+    const ArchiveManager::StorageStats& stats,
+    const MultipleOfflinePageItemResult& pages) {
+  std::vector<int64_t> offline_ids;
+  GetExpiredPageIds(pages, stats, offline_ids);
+  client_->DeletePagesByOfflineId(
+      offline_ids,
+      base::Bind(&OfflinePageStorageManager::OnExpiredPagesDeleted,
+                 weak_ptr_factory_.GetWeakPtr(), callback, offline_ids.size()));
+}
+
+void OfflinePageStorageManager::OnExpiredPagesDeleted(
+    const ClearPagesCallback& callback,
+    int pages_cleared,
+    DeletePageResult result) {
+  last_clear_time_ = clock_->Now();
+  ClearStorageResult clear_result = result == DeletePageResult::SUCCESS
+                                        ? ClearStorageResult::SUCCESS
+                                        : ClearStorageResult::DELETE_FAILURE;
+  in_progress_ = false;
+  callback.Run(pages_cleared, clear_result);
+}
+
 void OfflinePageStorageManager::GetExpiredPageIds(
     const MultipleOfflinePageItemResult& pages,
+    const ArchiveManager::StorageStats& stats,
     std::vector<int64_t>& offline_ids) {
   base::Time now = clock_->Now();
 
   // Creating a map from namespace to a vector of page items.
   // Sort each vector based on last accessed time and all pages after index
   // min{size(), page_limit} should be expired. And then start iterating
   // backwards to expire pages.
   std::map<std::string, std::vector<OfflinePageItem>> pages_map;
+  std::vector<OfflinePageItem> kept_pages;
+  int64_t kept_pages_size = 0;
 
   for (const auto& page : pages)
     pages_map[page.client_id.name_space].push_back(page);
 
   for (auto& iter : pages_map) {
     std::string name_space = iter.first;
     std::vector<OfflinePageItem>& page_list = iter.second;
 
     LifetimePolicy policy =
         policy_controller_->GetPolicy(name_space).lifetime_policy;
 
     std::sort(page_list.begin(), page_list.end(),
               [](const OfflinePageItem& a, const OfflinePageItem& b) -> bool {
                 return a.last_access_time > b.last_access_time;
               });
 
     int page_list_size = page_list.size();
     int pos = 0;
     while (pos < page_list_size &&
            (policy.page_limit == kUnlimitedPages || pos < policy.page_limit) &&
            !ShouldBeExpired(now, page_list.at(pos))) {
+      kept_pages_size += page_list.at(pos).file_size;
+      kept_pages.push_back(page_list.at(pos));
       pos++;
     }
 
-    for (int i = pos; i < page_list_size; i++)
-      offline_ids.push_back(page_list.at(i).offline_id);
+    for (; pos < page_list_size; pos++)
+      offline_ids.push_back(page_list.at(pos).offline_id);
+  }
+
+  // If we're still over the clear threshold, we're going to clear remaining
+  // pages from oldest last access time.
+  int64_t free_space = stats.free_disk_space;
+  int64_t total_size = stats.total_archives_size;
+  int64_t space_to_release =
+      kept_pages_size -
+      (total_size + free_space) * kOfflinePageStorageClearThreshold;
+  if (space_to_release > 0) {
+    // Here we're sorting the |kept_pages| with oldest first.
+    std::sort(kept_pages.begin(), kept_pages.end(),
+              [](const OfflinePageItem& a, const OfflinePageItem& b) -> bool {
+                return a.last_access_time < b.last_access_time;
+              });
+    int kept_pages_size = kept_pages.size();
+    int pos = 0;
+    while (pos < kept_pages_size && space_to_release > 0) {
+      space_to_release -= kept_pages.at(pos).file_size;
+      offline_ids.push_back(kept_pages.at(pos).offline_id);
+      pos++;
+    }
   }
 }
 
-void OfflinePageStorageManager::OnExpiredPagesDeleted(
-    const ClearPageCallback& callback,
-    int pages_cleared,
-    DeletePageResult result) {
-  in_progress_ = false;
-  callback.Run(pages_cleared, result);
-}
+OfflinePageStorageManager::ClearMode
+OfflinePageStorageManager::ShouldClearPages(
+    const ArchiveManager::StorageStats& storage_stats) {
+  int64_t total_size = storage_stats.total_archives_size;
+  int64_t free_space = storage_stats.free_disk_space;
+  if (total_size == 0)
+    return ClearMode::NOT_NEEDED;
 
-bool OfflinePageStorageManager::ShouldClearPages() {
-  return !in_progress_;
+  // If the size of all offline pages is more than limit, or it's larger than a
+  // specified percentage of all available storage space on the disk we'll clear
+  // all offline pages.
+  if (total_size >= (total_size + free_space) * kOfflinePageStorageLimit)
+    return ClearMode::DEFAULT;
+  // If it's been more than the pre-defined interval since the last time we
+  // clear the storage, we should clear pages.
+  if (last_clear_time_ == base::Time() ||
+      clock_->Now() - last_clear_time_ >= kClearStorageInterval) {
+    return ClearMode::DEFAULT;
+  }
+
+  // Otherwise there's no need to clear storage right now.
+  return ClearMode::NOT_NEEDED;
 }
 
 bool OfflinePageStorageManager::ShouldBeExpired(const base::Time& now,
                                                 const OfflinePageItem& page) {
   const LifetimePolicy& policy =
       policy_controller_->GetPolicy(page.client_id.name_space).lifetime_policy;
-  return now - page.last_access_time > policy.expiration_period;
+  return now - page.last_access_time >= policy.expiration_period;
 }
 
 }  // namespace offline_pages