root/webkit/browser/appcache/mock_appcache_storage.cc

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DEFINITIONS

This source file includes following definitions.
  1. weak_factory_
  2. GetAllInfo
  3. LoadCache
  4. LoadOrCreateGroup
  5. StoreGroupAndNewestCache
  6. FindResponseForMainRequest
  7. FindResponseForSubRequest
  8. MarkEntryAsForeign
  9. MakeGroupObsolete
  10. CreateResponseReader
  11. CreateResponseWriter
  12. DoomResponses
  13. DeleteResponses
  14. ProcessGetAllInfo
  15. ProcessLoadCache
  16. ProcessLoadOrCreateGroup
  17. ProcessStoreGroupAndNewestCache
  18. MaybeTakeNewNamespaceEntry
  19. ProcessFindResponseForMainRequest
  20. ProcessMakeGroupObsolete
  21. ScheduleTask
  22. RunOnePendingTask
  23. AddStoredCache
  24. RemoveStoredCache
  25. RemoveStoredCaches
  26. AddStoredGroup
  27. RemoveStoredGroup
  28. ShouldGroupLoadAppearAsync
  29. ShouldCacheLoadAppearAsync

// Copyright (c) 2011 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 "webkit/browser/appcache/mock_appcache_storage.h"

#include "base/bind.h"
#include "base/logging.h"
#include "base/memory/ref_counted.h"
#include "base/message_loop/message_loop.h"
#include "base/stl_util.h"
#include "webkit/browser/appcache/appcache.h"
#include "webkit/browser/appcache/appcache_entry.h"
#include "webkit/browser/appcache/appcache_group.h"
#include "webkit/browser/appcache/appcache_response.h"
#include "webkit/browser/appcache/appcache_service.h"

// This is a quick and easy 'mock' implementation of the storage interface
// that doesn't put anything to disk.
//
// We simply add an extra reference to objects when they're put in storage,
// and remove the extra reference when they are removed from storage.
// Responses are never really removed from the in-memory disk cache.
// Delegate callbacks are made asyncly to appropiately mimic what will
// happen with a real disk-backed storage impl that involves IO on a
// background thread.

namespace appcache {

MockAppCacheStorage::MockAppCacheStorage(AppCacheService* service)
    : AppCacheStorage(service),
      simulate_make_group_obsolete_failure_(false),
      simulate_store_group_and_newest_cache_failure_(false),
      simulate_find_main_resource_(false),
      simulate_find_sub_resource_(false),
      simulated_found_cache_id_(kNoCacheId),
      simulated_found_group_id_(0),
      simulated_found_network_namespace_(false),
      weak_factory_(this) {
  last_cache_id_ = 0;
  last_group_id_ = 0;
  last_response_id_ = 0;
}

MockAppCacheStorage::~MockAppCacheStorage() {
}

void MockAppCacheStorage::GetAllInfo(Delegate* delegate) {
  ScheduleTask(
      base::Bind(&MockAppCacheStorage::ProcessGetAllInfo,
                 weak_factory_.GetWeakPtr(),
                 make_scoped_refptr(GetOrCreateDelegateReference(delegate))));
}

void MockAppCacheStorage::LoadCache(int64 id, Delegate* delegate) {
  DCHECK(delegate);
  AppCache* cache = working_set_.GetCache(id);
  if (ShouldCacheLoadAppearAsync(cache)) {
    ScheduleTask(
        base::Bind(&MockAppCacheStorage::ProcessLoadCache,
                   weak_factory_.GetWeakPtr(), id,
                   make_scoped_refptr(GetOrCreateDelegateReference(delegate))));
    return;
  }
  ProcessLoadCache(id, GetOrCreateDelegateReference(delegate));
}

void MockAppCacheStorage::LoadOrCreateGroup(
    const GURL& manifest_url, Delegate* delegate) {
  DCHECK(delegate);
  AppCacheGroup* group = working_set_.GetGroup(manifest_url);
  if (ShouldGroupLoadAppearAsync(group)) {
    ScheduleTask(
        base::Bind(&MockAppCacheStorage::ProcessLoadOrCreateGroup,
                   weak_factory_.GetWeakPtr(), manifest_url,
                   make_scoped_refptr(GetOrCreateDelegateReference(delegate))));
    return;
  }
  ProcessLoadOrCreateGroup(
      manifest_url, GetOrCreateDelegateReference(delegate));
}

void MockAppCacheStorage::StoreGroupAndNewestCache(
    AppCacheGroup* group, AppCache* newest_cache, Delegate* delegate) {
  DCHECK(group && delegate && newest_cache);

  // Always make this operation look async.
  ScheduleTask(
      base::Bind(&MockAppCacheStorage::ProcessStoreGroupAndNewestCache,
                 weak_factory_.GetWeakPtr(), make_scoped_refptr(group),
                 make_scoped_refptr(newest_cache),
                 make_scoped_refptr(GetOrCreateDelegateReference(delegate))));
}

void MockAppCacheStorage::FindResponseForMainRequest(
    const GURL& url, const GURL& preferred_manifest_url, Delegate* delegate) {
  DCHECK(delegate);

  // Note: MockAppCacheStorage does not respect the preferred_manifest_url.

  // Always make this operation look async.
  ScheduleTask(
      base::Bind(&MockAppCacheStorage::ProcessFindResponseForMainRequest,
                 weak_factory_.GetWeakPtr(), url,
                 make_scoped_refptr(GetOrCreateDelegateReference(delegate))));
}

void MockAppCacheStorage::FindResponseForSubRequest(
    AppCache* cache, const GURL& url,
    AppCacheEntry* found_entry, AppCacheEntry* found_fallback_entry,
    bool* found_network_namespace) {
  DCHECK(cache && cache->is_complete());

  // This layer of indirection is here to facilitate testing.
  if (simulate_find_sub_resource_) {
    *found_entry = simulated_found_entry_;
    *found_fallback_entry = simulated_found_fallback_entry_;
    *found_network_namespace = simulated_found_network_namespace_;
    simulate_find_sub_resource_ = false;
    return;
  }

  GURL fallback_namespace_not_used;
  GURL intercept_namespace_not_used;
  cache->FindResponseForRequest(
      url, found_entry, &intercept_namespace_not_used,
      found_fallback_entry,  &fallback_namespace_not_used,
      found_network_namespace);
}

void MockAppCacheStorage::MarkEntryAsForeign(
    const GURL& entry_url, int64 cache_id) {
  AppCache* cache = working_set_.GetCache(cache_id);
  if (cache) {
    AppCacheEntry* entry = cache->GetEntry(entry_url);
    DCHECK(entry);
    if (entry)
      entry->add_types(AppCacheEntry::FOREIGN);
  }
}

void MockAppCacheStorage::MakeGroupObsolete(AppCacheGroup* group,
                                            Delegate* delegate,
                                            int response_code) {
  DCHECK(group && delegate);

  // Always make this method look async.
  ScheduleTask(
      base::Bind(&MockAppCacheStorage::ProcessMakeGroupObsolete,
                 weak_factory_.GetWeakPtr(),
                 make_scoped_refptr(group),
                 make_scoped_refptr(GetOrCreateDelegateReference(delegate)),
                 response_code));
}

AppCacheResponseReader* MockAppCacheStorage::CreateResponseReader(
    const GURL& manifest_url, int64 group_id, int64 response_id) {
  if (simulated_reader_)
    return simulated_reader_.release();
  return new AppCacheResponseReader(response_id, group_id, disk_cache());
}

AppCacheResponseWriter* MockAppCacheStorage::CreateResponseWriter(
    const GURL& manifest_url, int64 group_id) {
  return new AppCacheResponseWriter(NewResponseId(),  group_id, disk_cache());
}

void MockAppCacheStorage::DoomResponses(
    const GURL& manifest_url, const std::vector<int64>& response_ids) {
  DeleteResponses(manifest_url, response_ids);
}

void MockAppCacheStorage::DeleteResponses(
    const GURL& manifest_url, const std::vector<int64>& response_ids) {
  // We don't bother with actually removing responses from the disk-cache,
  // just keep track of which ids have been doomed or deleted
  std::vector<int64>::const_iterator it = response_ids.begin();
  while (it != response_ids.end()) {
    doomed_response_ids_.insert(*it);
    ++it;
  }
}

void MockAppCacheStorage::ProcessGetAllInfo(
    scoped_refptr<DelegateReference> delegate_ref) {
  if (delegate_ref->delegate)
    delegate_ref->delegate->OnAllInfo(simulated_appcache_info_.get());
}

void MockAppCacheStorage::ProcessLoadCache(
    int64 id, scoped_refptr<DelegateReference> delegate_ref) {
  AppCache* cache = working_set_.GetCache(id);
  if (delegate_ref->delegate)
    delegate_ref->delegate->OnCacheLoaded(cache, id);
}

void MockAppCacheStorage::ProcessLoadOrCreateGroup(
    const GURL& manifest_url, scoped_refptr<DelegateReference> delegate_ref) {
  scoped_refptr<AppCacheGroup> group(working_set_.GetGroup(manifest_url));

  // Newly created groups are not put in the stored_groups collection
  // until StoreGroupAndNewestCache is called.
  if (!group.get())
    group = new AppCacheGroup(service_->storage(), manifest_url, NewGroupId());

  if (delegate_ref->delegate)
    delegate_ref->delegate->OnGroupLoaded(group.get(), manifest_url);
}

void MockAppCacheStorage::ProcessStoreGroupAndNewestCache(
    scoped_refptr<AppCacheGroup> group,
    scoped_refptr<AppCache> newest_cache,
    scoped_refptr<DelegateReference> delegate_ref) {
  Delegate* delegate = delegate_ref->delegate;
  if (simulate_store_group_and_newest_cache_failure_) {
    if (delegate)
      delegate->OnGroupAndNewestCacheStored(
          group.get(), newest_cache.get(), false, false);
    return;
  }

  AddStoredGroup(group.get());
  if (newest_cache.get() != group->newest_complete_cache()) {
    newest_cache->set_complete(true);
    group->AddCache(newest_cache.get());
    AddStoredCache(newest_cache.get());

    // Copy the collection prior to removal, on final release
    // of a cache the group's collection will change.
    AppCacheGroup::Caches copy = group->old_caches();
    RemoveStoredCaches(copy);
  }

  if (delegate)
    delegate->OnGroupAndNewestCacheStored(
        group.get(), newest_cache.get(), true, false);
}

namespace {

struct FoundCandidate {
  GURL namespace_entry_url;
  AppCacheEntry entry;
  int64 cache_id;
  int64 group_id;
  GURL manifest_url;
  bool is_cache_in_use;

  FoundCandidate()
      : cache_id(kNoCacheId), group_id(0), is_cache_in_use(false) {}
};

void MaybeTakeNewNamespaceEntry(
    NamespaceType namespace_type,
    const AppCacheEntry &entry,
    const GURL& namespace_url,
    bool cache_is_in_use,
    FoundCandidate* best_candidate,
    GURL* best_candidate_namespace,
    AppCache* cache,
    AppCacheGroup* group) {
  DCHECK(entry.has_response_id());

  bool take_new_entry = true;

  // Does the new candidate entry trump our current best candidate?
  if (best_candidate->entry.has_response_id()) {
    // Longer namespace prefix matches win.
    size_t candidate_length =
        namespace_url.spec().length();
    size_t best_length =
        best_candidate_namespace->spec().length();

    if (candidate_length > best_length) {
      take_new_entry = true;
    } else if (candidate_length == best_length &&
               cache_is_in_use && !best_candidate->is_cache_in_use) {
      take_new_entry = true;
    } else {
      take_new_entry = false;
    }
  }

  if (take_new_entry) {
    if (namespace_type == FALLBACK_NAMESPACE) {
      best_candidate->namespace_entry_url =
          cache->GetFallbackEntryUrl(namespace_url);
    } else {
      best_candidate->namespace_entry_url =
          cache->GetInterceptEntryUrl(namespace_url);
    }
    best_candidate->entry = entry;
    best_candidate->cache_id = cache->cache_id();
    best_candidate->group_id = group->group_id();
    best_candidate->manifest_url = group->manifest_url();
    best_candidate->is_cache_in_use = cache_is_in_use;
    *best_candidate_namespace = namespace_url;
  }
}
}  // namespace

void MockAppCacheStorage::ProcessFindResponseForMainRequest(
    const GURL& url, scoped_refptr<DelegateReference> delegate_ref) {
  if (simulate_find_main_resource_) {
    simulate_find_main_resource_ = false;
    if (delegate_ref->delegate) {
      delegate_ref->delegate->OnMainResponseFound(
          url, simulated_found_entry_,
          simulated_found_fallback_url_, simulated_found_fallback_entry_,
          simulated_found_cache_id_, simulated_found_group_id_,
          simulated_found_manifest_url_);
    }
    return;
  }

  // This call has no persistent side effects, if the delegate has gone
  // away, we can just bail out early.
  if (!delegate_ref->delegate)
    return;

  // TODO(michaeln): The heuristics around choosing amoungst
  // multiple candidates is under specified, and just plain
  // not fully understood. Refine these over time. In particular,
  // * prefer candidates from newer caches
  // * take into account the cache associated with the document
  //   that initiated the navigation
  // * take into account the cache associated with the document
  //   currently residing in the frame being navigated
  FoundCandidate found_candidate;
  GURL found_intercept_candidate_namespace;
  FoundCandidate found_fallback_candidate;
  GURL found_fallback_candidate_namespace;

  for (StoredGroupMap::const_iterator it = stored_groups_.begin();
       it != stored_groups_.end(); ++it) {
    AppCacheGroup* group = it->second.get();
    AppCache* cache = group->newest_complete_cache();
    if (group->is_obsolete() || !cache ||
        (url.GetOrigin() != group->manifest_url().GetOrigin())) {
      continue;
    }

    AppCacheEntry found_entry;
    AppCacheEntry found_fallback_entry;
    GURL found_intercept_namespace;
    GURL found_fallback_namespace;
    bool ignore_found_network_namespace = false;
    bool found = cache->FindResponseForRequest(
                            url, &found_entry, &found_intercept_namespace,
                            &found_fallback_entry, &found_fallback_namespace,
                            &ignore_found_network_namespace);

    // 6.11.1 Navigating across documents, Step 10.
    // Network namespacing doesn't apply to main resource loads,
    // and foreign entries are excluded.
    if (!found || ignore_found_network_namespace ||
        (found_entry.has_response_id() && found_entry.IsForeign()) ||
        (found_fallback_entry.has_response_id() &&
         found_fallback_entry.IsForeign())) {
      continue;
    }

    // We have a bias for hits from caches that are in use.
    bool is_in_use = IsCacheStored(cache) && !cache->HasOneRef();

    if (found_entry.has_response_id() &&
        found_intercept_namespace.is_empty()) {
      found_candidate.namespace_entry_url = GURL();
      found_candidate.entry = found_entry;
      found_candidate.cache_id = cache->cache_id();
      found_candidate.group_id = group->group_id();
      found_candidate.manifest_url = group->manifest_url();
      found_candidate.is_cache_in_use = is_in_use;
      if (is_in_use)
        break;  // We break out of the loop with this direct hit.
    } else if (found_entry.has_response_id() &&
               !found_intercept_namespace.is_empty()) {
      MaybeTakeNewNamespaceEntry(
          INTERCEPT_NAMESPACE,
          found_entry, found_intercept_namespace, is_in_use,
          &found_candidate, &found_intercept_candidate_namespace,
          cache, group);
    } else {
      DCHECK(found_fallback_entry.has_response_id());
      MaybeTakeNewNamespaceEntry(
          FALLBACK_NAMESPACE,
          found_fallback_entry, found_fallback_namespace, is_in_use,
          &found_fallback_candidate, &found_fallback_candidate_namespace,
          cache, group);
    }
  }

  // Found a direct hit or an intercept namespace hit.
  if (found_candidate.entry.has_response_id()) {
    delegate_ref->delegate->OnMainResponseFound(
        url, found_candidate.entry, found_candidate.namespace_entry_url,
        AppCacheEntry(),  found_candidate.cache_id, found_candidate.group_id,
        found_candidate.manifest_url);
    return;
  }

  // Found a fallback namespace.
  if (found_fallback_candidate.entry.has_response_id()) {
    delegate_ref->delegate->OnMainResponseFound(
        url, AppCacheEntry(),
        found_fallback_candidate.namespace_entry_url,
        found_fallback_candidate.entry,
        found_fallback_candidate.cache_id,
        found_fallback_candidate.group_id,
        found_fallback_candidate.manifest_url);
    return;
  }

  // Didn't find anything.
  delegate_ref->delegate->OnMainResponseFound(
      url, AppCacheEntry(), GURL(), AppCacheEntry(), kNoCacheId, 0, GURL());
}

void MockAppCacheStorage::ProcessMakeGroupObsolete(
    scoped_refptr<AppCacheGroup> group,
    scoped_refptr<DelegateReference> delegate_ref,
    int response_code) {
  if (simulate_make_group_obsolete_failure_) {
    if (delegate_ref->delegate)
      delegate_ref->delegate->OnGroupMadeObsolete(
          group.get(), false, response_code);
    return;
  }

  RemoveStoredGroup(group.get());
  if (group->newest_complete_cache())
    RemoveStoredCache(group->newest_complete_cache());

  // Copy the collection prior to removal, on final release
  // of a cache the group's collection will change.
  AppCacheGroup::Caches copy = group->old_caches();
  RemoveStoredCaches(copy);

  group->set_obsolete(true);

  // Also remove from the working set, caches for an 'obsolete' group
  // may linger in use, but the group itself cannot be looked up by
  // 'manifest_url' in the working set any longer.
  working_set()->RemoveGroup(group.get());

  if (delegate_ref->delegate)
    delegate_ref->delegate->OnGroupMadeObsolete(
        group.get(), true, response_code);
}

void MockAppCacheStorage::ScheduleTask(const base::Closure& task) {
  pending_tasks_.push_back(task);
  base::MessageLoop::current()->PostTask(
      FROM_HERE,
      base::Bind(&MockAppCacheStorage::RunOnePendingTask,
                 weak_factory_.GetWeakPtr()));
}

void MockAppCacheStorage::RunOnePendingTask() {
  DCHECK(!pending_tasks_.empty());
  base::Closure task = pending_tasks_.front();
  pending_tasks_.pop_front();
  task.Run();
}

void MockAppCacheStorage::AddStoredCache(AppCache* cache) {
  int64 cache_id = cache->cache_id();
  if (stored_caches_.find(cache_id) == stored_caches_.end()) {
    stored_caches_.insert(
        StoredCacheMap::value_type(cache_id, make_scoped_refptr(cache)));
  }
}

void MockAppCacheStorage::RemoveStoredCache(AppCache* cache) {
  // Do not remove from the working set, active caches are still usable
  // and may be looked up by id until they fall out of use.
  stored_caches_.erase(cache->cache_id());
}

void MockAppCacheStorage::RemoveStoredCaches(
    const AppCacheGroup::Caches& caches) {
  AppCacheGroup::Caches::const_iterator it = caches.begin();
  while (it != caches.end()) {
    RemoveStoredCache(*it);
    ++it;
  }
}

void MockAppCacheStorage::AddStoredGroup(AppCacheGroup* group) {
  const GURL& url = group->manifest_url();
  if (stored_groups_.find(url) == stored_groups_.end()) {
    stored_groups_.insert(
        StoredGroupMap::value_type(url, make_scoped_refptr(group)));
  }
}

void MockAppCacheStorage::RemoveStoredGroup(AppCacheGroup* group) {
  stored_groups_.erase(group->manifest_url());
}

bool MockAppCacheStorage::ShouldGroupLoadAppearAsync(
    const AppCacheGroup* group) {
  // We'll have to query the database to see if a group for the
  // manifest_url exists on disk. So return true for async.
  if (!group)
    return true;

  // Groups without a newest cache can't have been put to disk yet, so
  // we can synchronously return a reference we have in the working set.
  if (!group->newest_complete_cache())
    return false;

  // The LoadGroup interface implies also loading the newest cache, so
  // if loading the newest cache should appear async, so too must the
  // loading of this group.
  if (!ShouldCacheLoadAppearAsync(group->newest_complete_cache()))
    return false;


  // If any of the old caches are "in use", then the group must also
  // be memory resident and not require async loading.
  const AppCacheGroup::Caches& old_caches = group->old_caches();
  AppCacheGroup::Caches::const_iterator it = old_caches.begin();
  while (it != old_caches.end()) {
    // "in use" caches don't require async loading
    if (!ShouldCacheLoadAppearAsync(*it))
      return false;
    ++it;
  }

  return true;
}

bool MockAppCacheStorage::ShouldCacheLoadAppearAsync(const AppCache* cache) {
  if (!cache)
    return true;

  // If the 'stored' ref is the only ref, real storage will have to load from
  // the database.
  return IsCacheStored(cache) && cache->HasOneRef();
}

}  // namespace appcache

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