Add ICU message format support
[chromium-blink-merge.git] / content / browser / storage_partition_impl_map.cc
blob8b99d0428c766d558ca97edbb895433ee10157be
1 // Copyright (c) 2012 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.
5 #include "content/browser/storage_partition_impl_map.h"
7 #include "base/bind.h"
8 #include "base/callback.h"
9 #include "base/files/file_enumerator.h"
10 #include "base/files/file_path.h"
11 #include "base/files/file_util.h"
12 #include "base/location.h"
13 #include "base/single_thread_task_runner.h"
14 #include "base/stl_util.h"
15 #include "base/strings/string_number_conversions.h"
16 #include "base/strings/string_util.h"
17 #include "base/strings/stringprintf.h"
18 #include "base/thread_task_runner_handle.h"
19 #include "base/threading/sequenced_worker_pool.h"
20 #include "content/browser/appcache/appcache_interceptor.h"
21 #include "content/browser/appcache/chrome_appcache_service.h"
22 #include "content/browser/fileapi/browser_file_system_helper.h"
23 #include "content/browser/fileapi/chrome_blob_storage_context.h"
24 #include "content/browser/loader/resource_request_info_impl.h"
25 #include "content/browser/resource_context_impl.h"
26 #include "content/browser/service_worker/service_worker_request_handler.h"
27 #include "content/browser/storage_partition_impl.h"
28 #include "content/browser/streams/stream.h"
29 #include "content/browser/streams/stream_context.h"
30 #include "content/browser/streams/stream_registry.h"
31 #include "content/browser/streams/stream_url_request_job.h"
32 #include "content/browser/webui/url_data_manager_backend.h"
33 #include "content/public/browser/browser_context.h"
34 #include "content/public/browser/browser_thread.h"
35 #include "content/public/browser/content_browser_client.h"
36 #include "content/public/browser/navigator_connect_context.h"
37 #include "content/public/browser/navigator_connect_service_factory.h"
38 #include "content/public/browser/storage_partition.h"
39 #include "content/public/common/content_constants.h"
40 #include "content/public/common/url_constants.h"
41 #include "crypto/sha2.h"
42 #include "net/url_request/url_request_context.h"
43 #include "net/url_request/url_request_context_getter.h"
44 #include "storage/browser/blob/blob_storage_context.h"
45 #include "storage/browser/blob/blob_url_request_job_factory.h"
46 #include "storage/browser/fileapi/file_system_url_request_job_factory.h"
48 using storage::FileSystemContext;
49 using storage::BlobStorageContext;
51 namespace content {
53 namespace {
55 // A derivative that knows about Streams too.
56 class BlobProtocolHandler : public net::URLRequestJobFactory::ProtocolHandler {
57 public:
58 BlobProtocolHandler(ChromeBlobStorageContext* blob_storage_context,
59 StreamContext* stream_context,
60 storage::FileSystemContext* file_system_context)
61 : blob_storage_context_(blob_storage_context),
62 stream_context_(stream_context),
63 file_system_context_(file_system_context) {}
65 ~BlobProtocolHandler() override {}
67 net::URLRequestJob* MaybeCreateJob(
68 net::URLRequest* request,
69 net::NetworkDelegate* network_delegate) const override {
70 scoped_refptr<Stream> stream =
71 stream_context_->registry()->GetStream(request->url());
72 if (stream.get())
73 return new StreamURLRequestJob(request, network_delegate, stream);
75 if (!blob_protocol_handler_) {
76 // Construction is deferred because 'this' is constructed on
77 // the main thread but we want blob_protocol_handler_ constructed
78 // on the IO thread.
79 blob_protocol_handler_.reset(new storage::BlobProtocolHandler(
80 blob_storage_context_->context(),
81 file_system_context_.get(),
82 BrowserThread::GetMessageLoopProxyForThread(BrowserThread::FILE)
83 .get()));
85 return blob_protocol_handler_->MaybeCreateJob(request, network_delegate);
88 private:
89 const scoped_refptr<ChromeBlobStorageContext> blob_storage_context_;
90 const scoped_refptr<StreamContext> stream_context_;
91 const scoped_refptr<storage::FileSystemContext> file_system_context_;
92 mutable scoped_ptr<storage::BlobProtocolHandler> blob_protocol_handler_;
93 DISALLOW_COPY_AND_ASSIGN(BlobProtocolHandler);
96 // These constants are used to create the directory structure under the profile
97 // where renderers with a non-default storage partition keep their persistent
98 // state. This will contain a set of directories that partially mirror the
99 // directory structure of BrowserContext::GetPath().
101 // The kStoragePartitionDirname contains an extensions directory which is
102 // further partitioned by extension id, followed by another level of directories
103 // for the "default" extension storage partition and one directory for each
104 // persistent partition used by a webview tag. Example:
106 // Storage/ext/ABCDEF/def
107 // Storage/ext/ABCDEF/hash(partition name)
109 // The code in GetStoragePartitionPath() constructs these path names.
111 // TODO(nasko): Move extension related path code out of content.
112 const base::FilePath::CharType kStoragePartitionDirname[] =
113 FILE_PATH_LITERAL("Storage");
114 const base::FilePath::CharType kExtensionsDirname[] =
115 FILE_PATH_LITERAL("ext");
116 const base::FilePath::CharType kDefaultPartitionDirname[] =
117 FILE_PATH_LITERAL("def");
118 const base::FilePath::CharType kTrashDirname[] =
119 FILE_PATH_LITERAL("trash");
121 // Because partition names are user specified, they can be arbitrarily long
122 // which makes them unsuitable for paths names. We use a truncation of a
123 // SHA256 hash to perform a deterministic shortening of the string. The
124 // kPartitionNameHashBytes constant controls the length of the truncation.
125 // We use 6 bytes, which gives us 99.999% reliability against collisions over
126 // 1 million partition domains.
128 // Analysis:
129 // We assume that all partition names within one partition domain are
130 // controlled by the the same entity. Thus there is no chance for adverserial
131 // attack and all we care about is accidental collision. To get 5 9s over
132 // 1 million domains, we need the probability of a collision in any one domain
133 // to be
135 // p < nroot(1000000, .99999) ~= 10^-11
137 // We use the following birthday attack approximation to calculate the max
138 // number of unique names for this probability:
140 // n(p,H) = sqrt(2*H * ln(1/(1-p)))
142 // For a 6-byte hash, H = 2^(6*8). n(10^-11, H) ~= 75
144 // An average partition domain is likely to have less than 10 unique
145 // partition names which is far lower than 75.
147 // Note, that for 4 9s of reliability, the limit is 237 partition names per
148 // partition domain.
149 const int kPartitionNameHashBytes = 6;
151 // Needed for selecting all files in ObliterateOneDirectory() below.
152 #if defined(OS_POSIX)
153 const int kAllFileTypes = base::FileEnumerator::FILES |
154 base::FileEnumerator::DIRECTORIES |
155 base::FileEnumerator::SHOW_SYM_LINKS;
156 #else
157 const int kAllFileTypes = base::FileEnumerator::FILES |
158 base::FileEnumerator::DIRECTORIES;
159 #endif
161 base::FilePath GetStoragePartitionDomainPath(
162 const std::string& partition_domain) {
163 CHECK(base::IsStringUTF8(partition_domain));
165 return base::FilePath(kStoragePartitionDirname).Append(kExtensionsDirname)
166 .Append(base::FilePath::FromUTF8Unsafe(partition_domain));
169 // Helper function for doing a depth-first deletion of the data on disk.
170 // Examines paths directly in |current_dir| (no recursion) and tries to
171 // delete from disk anything that is in, or isn't a parent of something in
172 // |paths_to_keep|. Paths that need further expansion are added to
173 // |paths_to_consider|.
174 void ObliterateOneDirectory(const base::FilePath& current_dir,
175 const std::vector<base::FilePath>& paths_to_keep,
176 std::vector<base::FilePath>* paths_to_consider) {
177 CHECK(current_dir.IsAbsolute());
179 base::FileEnumerator enumerator(current_dir, false, kAllFileTypes);
180 for (base::FilePath to_delete = enumerator.Next(); !to_delete.empty();
181 to_delete = enumerator.Next()) {
182 // Enum tracking which of the 3 possible actions to take for |to_delete|.
183 enum { kSkip, kEnqueue, kDelete } action = kDelete;
185 for (std::vector<base::FilePath>::const_iterator to_keep =
186 paths_to_keep.begin();
187 to_keep != paths_to_keep.end();
188 ++to_keep) {
189 if (to_delete == *to_keep) {
190 action = kSkip;
191 break;
192 } else if (to_delete.IsParent(*to_keep)) {
193 // |to_delete| contains a path to keep. Add to stack for further
194 // processing.
195 action = kEnqueue;
196 break;
200 switch (action) {
201 case kDelete:
202 base::DeleteFile(to_delete, true);
203 break;
205 case kEnqueue:
206 paths_to_consider->push_back(to_delete);
207 break;
209 case kSkip:
210 break;
215 // Synchronously attempts to delete |unnormalized_root|, preserving only
216 // entries in |paths_to_keep|. If there are no entries in |paths_to_keep| on
217 // disk, then it completely removes |unnormalized_root|. All paths must be
218 // absolute paths.
219 void BlockingObliteratePath(
220 const base::FilePath& unnormalized_browser_context_root,
221 const base::FilePath& unnormalized_root,
222 const std::vector<base::FilePath>& paths_to_keep,
223 const scoped_refptr<base::TaskRunner>& closure_runner,
224 const base::Closure& on_gc_required) {
225 // Early exit required because MakeAbsoluteFilePath() will fail on POSIX
226 // if |unnormalized_root| does not exist. This is safe because there is
227 // nothing to do in this situation anwyays.
228 if (!base::PathExists(unnormalized_root)) {
229 return;
232 // Never try to obliterate things outside of the browser context root or the
233 // browser context root itself. Die hard.
234 base::FilePath root = base::MakeAbsoluteFilePath(unnormalized_root);
235 base::FilePath browser_context_root =
236 base::MakeAbsoluteFilePath(unnormalized_browser_context_root);
237 CHECK(!root.empty());
238 CHECK(!browser_context_root.empty());
239 CHECK(browser_context_root.IsParent(root) && browser_context_root != root);
241 // Reduce |paths_to_keep| set to those under the root and actually on disk.
242 std::vector<base::FilePath> valid_paths_to_keep;
243 for (std::vector<base::FilePath>::const_iterator it = paths_to_keep.begin();
244 it != paths_to_keep.end();
245 ++it) {
246 if (root.IsParent(*it) && base::PathExists(*it))
247 valid_paths_to_keep.push_back(*it);
250 // If none of the |paths_to_keep| are valid anymore then we just whack the
251 // root and be done with it. Otherwise, signal garbage collection and do
252 // a best-effort delete of the on-disk structures.
253 if (valid_paths_to_keep.empty()) {
254 base::DeleteFile(root, true);
255 return;
257 closure_runner->PostTask(FROM_HERE, on_gc_required);
259 // Otherwise, start at the root and delete everything that is not in
260 // |valid_paths_to_keep|.
261 std::vector<base::FilePath> paths_to_consider;
262 paths_to_consider.push_back(root);
263 while(!paths_to_consider.empty()) {
264 base::FilePath path = paths_to_consider.back();
265 paths_to_consider.pop_back();
266 ObliterateOneDirectory(path, valid_paths_to_keep, &paths_to_consider);
270 // Ensures each path in |active_paths| is a direct child of storage_root.
271 void NormalizeActivePaths(const base::FilePath& storage_root,
272 base::hash_set<base::FilePath>* active_paths) {
273 base::hash_set<base::FilePath> normalized_active_paths;
275 for (base::hash_set<base::FilePath>::iterator iter = active_paths->begin();
276 iter != active_paths->end(); ++iter) {
277 base::FilePath relative_path;
278 if (!storage_root.AppendRelativePath(*iter, &relative_path))
279 continue;
281 std::vector<base::FilePath::StringType> components;
282 relative_path.GetComponents(&components);
284 DCHECK(!relative_path.empty());
285 normalized_active_paths.insert(storage_root.Append(components.front()));
288 active_paths->swap(normalized_active_paths);
291 // Deletes all entries inside the |storage_root| that are not in the
292 // |active_paths|. Deletion is done in 2 steps:
294 // (1) Moving all garbage collected paths into a trash directory.
295 // (2) Asynchronously deleting the trash directory.
297 // The deletion is asynchronous because after (1) completes, calling code can
298 // safely continue to use the paths that had just been garbage collected
299 // without fear of race conditions.
301 // This code also ignores failed moves rather than attempting a smarter retry.
302 // Moves shouldn't fail here unless there is some out-of-band error (eg.,
303 // FS corruption). Retry logic is dangerous in the general case because
304 // there is not necessarily a guaranteed case where the logic may succeed.
306 // This function is still named BlockingGarbageCollect() because it does
307 // execute a few filesystem operations synchronously.
308 void BlockingGarbageCollect(
309 const base::FilePath& storage_root,
310 const scoped_refptr<base::TaskRunner>& file_access_runner,
311 scoped_ptr<base::hash_set<base::FilePath> > active_paths) {
312 CHECK(storage_root.IsAbsolute());
314 NormalizeActivePaths(storage_root, active_paths.get());
316 base::FileEnumerator enumerator(storage_root, false, kAllFileTypes);
317 base::FilePath trash_directory;
318 if (!base::CreateTemporaryDirInDir(storage_root, kTrashDirname,
319 &trash_directory)) {
320 // Unable to continue without creating the trash directory so give up.
321 return;
323 for (base::FilePath path = enumerator.Next(); !path.empty();
324 path = enumerator.Next()) {
325 if (active_paths->find(path) == active_paths->end() &&
326 path != trash_directory) {
327 // Since |trash_directory| is unique for each run of this function there
328 // can be no colllisions on the move.
329 base::Move(path, trash_directory.Append(path.BaseName()));
333 file_access_runner->PostTask(
334 FROM_HERE,
335 base::Bind(base::IgnoreResult(&base::DeleteFile), trash_directory, true));
338 } // namespace
340 // static
341 base::FilePath StoragePartitionImplMap::GetStoragePartitionPath(
342 const std::string& partition_domain,
343 const std::string& partition_name) {
344 if (partition_domain.empty())
345 return base::FilePath();
347 base::FilePath path = GetStoragePartitionDomainPath(partition_domain);
349 // TODO(ajwong): Mangle in-memory into this somehow, either by putting
350 // it into the partition_name, or by manually adding another path component
351 // here. Otherwise, it's possible to have an in-memory StoragePartition and
352 // a persistent one that return the same FilePath for GetPath().
353 if (!partition_name.empty()) {
354 // For analysis of why we can ignore collisions, see the comment above
355 // kPartitionNameHashBytes.
356 char buffer[kPartitionNameHashBytes];
357 crypto::SHA256HashString(partition_name, &buffer[0],
358 sizeof(buffer));
359 return path.AppendASCII(base::HexEncode(buffer, sizeof(buffer)));
362 return path.Append(kDefaultPartitionDirname);
365 StoragePartitionImplMap::StoragePartitionImplMap(
366 BrowserContext* browser_context)
367 : browser_context_(browser_context),
368 resource_context_initialized_(false) {
369 // Doing here instead of initializer list cause it's just too ugly to read.
370 base::SequencedWorkerPool* blocking_pool = BrowserThread::GetBlockingPool();
371 file_access_runner_ =
372 blocking_pool->GetSequencedTaskRunner(blocking_pool->GetSequenceToken());
375 StoragePartitionImplMap::~StoragePartitionImplMap() {
376 STLDeleteContainerPairSecondPointers(partitions_.begin(),
377 partitions_.end());
380 StoragePartitionImpl* StoragePartitionImplMap::Get(
381 const std::string& partition_domain,
382 const std::string& partition_name,
383 bool in_memory) {
384 // Find the previously created partition if it's available.
385 StoragePartitionConfig partition_config(
386 partition_domain, partition_name, in_memory);
388 PartitionMap::const_iterator it = partitions_.find(partition_config);
389 if (it != partitions_.end())
390 return it->second;
392 base::FilePath partition_path =
393 browser_context_->GetPath().Append(
394 GetStoragePartitionPath(partition_domain, partition_name));
395 StoragePartitionImpl* partition =
396 StoragePartitionImpl::Create(browser_context_, in_memory,
397 partition_path);
398 partitions_[partition_config] = partition;
400 ChromeBlobStorageContext* blob_storage_context =
401 ChromeBlobStorageContext::GetFor(browser_context_);
402 StreamContext* stream_context = StreamContext::GetFor(browser_context_);
403 ProtocolHandlerMap protocol_handlers;
404 protocol_handlers[url::kBlobScheme] =
405 linked_ptr<net::URLRequestJobFactory::ProtocolHandler>(
406 new BlobProtocolHandler(blob_storage_context,
407 stream_context,
408 partition->GetFileSystemContext()));
409 protocol_handlers[url::kFileSystemScheme] =
410 linked_ptr<net::URLRequestJobFactory::ProtocolHandler>(
411 CreateFileSystemProtocolHandler(partition_domain,
412 partition->GetFileSystemContext()));
413 protocol_handlers[kChromeUIScheme] =
414 linked_ptr<net::URLRequestJobFactory::ProtocolHandler>(
415 URLDataManagerBackend::CreateProtocolHandler(
416 browser_context_->GetResourceContext(),
417 browser_context_->IsOffTheRecord(),
418 partition->GetAppCacheService(),
419 blob_storage_context));
420 std::vector<std::string> additional_webui_schemes;
421 GetContentClient()->browser()->GetAdditionalWebUISchemes(
422 &additional_webui_schemes);
423 for (std::vector<std::string>::const_iterator it =
424 additional_webui_schemes.begin();
425 it != additional_webui_schemes.end();
426 ++it) {
427 protocol_handlers[*it] =
428 linked_ptr<net::URLRequestJobFactory::ProtocolHandler>(
429 URLDataManagerBackend::CreateProtocolHandler(
430 browser_context_->GetResourceContext(),
431 browser_context_->IsOffTheRecord(),
432 partition->GetAppCacheService(),
433 blob_storage_context));
435 protocol_handlers[kChromeDevToolsScheme] =
436 linked_ptr<net::URLRequestJobFactory::ProtocolHandler>(
437 CreateDevToolsProtocolHandler(browser_context_->GetResourceContext(),
438 browser_context_->IsOffTheRecord()));
440 URLRequestInterceptorScopedVector request_interceptors;
441 request_interceptors.push_back(
442 ServiceWorkerRequestHandler::CreateInterceptor(
443 browser_context_->GetResourceContext()).release());
444 request_interceptors.push_back(new AppCacheInterceptor());
446 // These calls must happen after StoragePartitionImpl::Create().
447 if (partition_domain.empty()) {
448 partition->SetURLRequestContext(
449 GetContentClient()->browser()->CreateRequestContext(
450 browser_context_,
451 &protocol_handlers,
452 request_interceptors.Pass()));
453 } else {
454 partition->SetURLRequestContext(
455 GetContentClient()->browser()->CreateRequestContextForStoragePartition(
456 browser_context_,
457 partition->GetPath(),
458 in_memory,
459 &protocol_handlers,
460 request_interceptors.Pass()));
462 partition->SetMediaURLRequestContext(
463 partition_domain.empty() ?
464 browser_context_->GetMediaRequestContext() :
465 browser_context_->GetMediaRequestContextForStoragePartition(
466 partition->GetPath(), in_memory));
468 GetContentClient()->browser()->GetAdditionalNavigatorConnectServices(
469 partition->GetNavigatorConnectContext());
471 PostCreateInitialization(partition, in_memory);
473 return partition;
476 void StoragePartitionImplMap::AsyncObliterate(
477 const GURL& site,
478 const base::Closure& on_gc_required) {
479 // This method should avoid creating any StoragePartition (which would
480 // create more open file handles) so that it can delete as much of the
481 // data off disk as possible.
482 std::string partition_domain;
483 std::string partition_name;
484 bool in_memory = false;
485 GetContentClient()->browser()->GetStoragePartitionConfigForSite(
486 browser_context_, site, false, &partition_domain,
487 &partition_name, &in_memory);
489 // Find the active partitions for the domain. Because these partitions are
490 // active, it is not possible to just delete the directories that contain
491 // the backing data structures without causing the browser to crash. Instead,
492 // of deleteing the directory, we tell each storage context later to
493 // remove any data they have saved. This will leave the directory structure
494 // intact but it will only contain empty databases.
495 std::vector<StoragePartitionImpl*> active_partitions;
496 std::vector<base::FilePath> paths_to_keep;
497 for (PartitionMap::const_iterator it = partitions_.begin();
498 it != partitions_.end();
499 ++it) {
500 const StoragePartitionConfig& config = it->first;
501 if (config.partition_domain == partition_domain) {
502 it->second->ClearData(
503 // All except shader cache.
504 ~StoragePartition::REMOVE_DATA_MASK_SHADER_CACHE,
505 StoragePartition::QUOTA_MANAGED_STORAGE_MASK_ALL,
506 GURL(),
507 StoragePartition::OriginMatcherFunction(),
508 base::Time(), base::Time::Max(),
509 base::Bind(&base::DoNothing));
510 if (!config.in_memory) {
511 paths_to_keep.push_back(it->second->GetPath());
516 // Start a best-effort delete of the on-disk storage excluding paths that are
517 // known to still be in use. This is to delete any previously created
518 // StoragePartition state that just happens to not have been used during this
519 // run of the browser.
520 base::FilePath domain_root = browser_context_->GetPath().Append(
521 GetStoragePartitionDomainPath(partition_domain));
523 BrowserThread::PostBlockingPoolTask(
524 FROM_HERE,
525 base::Bind(&BlockingObliteratePath, browser_context_->GetPath(),
526 domain_root, paths_to_keep,
527 base::ThreadTaskRunnerHandle::Get(), on_gc_required));
530 void StoragePartitionImplMap::GarbageCollect(
531 scoped_ptr<base::hash_set<base::FilePath> > active_paths,
532 const base::Closure& done) {
533 // Include all paths for current StoragePartitions in the active_paths since
534 // they cannot be deleted safely.
535 for (PartitionMap::const_iterator it = partitions_.begin();
536 it != partitions_.end();
537 ++it) {
538 const StoragePartitionConfig& config = it->first;
539 if (!config.in_memory)
540 active_paths->insert(it->second->GetPath());
543 // Find the directory holding the StoragePartitions and delete everything in
544 // there that isn't considered active.
545 base::FilePath storage_root = browser_context_->GetPath().Append(
546 GetStoragePartitionDomainPath(std::string()));
547 file_access_runner_->PostTaskAndReply(
548 FROM_HERE,
549 base::Bind(&BlockingGarbageCollect, storage_root,
550 file_access_runner_,
551 base::Passed(&active_paths)),
552 done);
555 void StoragePartitionImplMap::ForEach(
556 const BrowserContext::StoragePartitionCallback& callback) {
557 for (PartitionMap::const_iterator it = partitions_.begin();
558 it != partitions_.end();
559 ++it) {
560 callback.Run(it->second);
564 void StoragePartitionImplMap::PostCreateInitialization(
565 StoragePartitionImpl* partition,
566 bool in_memory) {
567 // TODO(ajwong): ResourceContexts no longer have any storage related state.
568 // We should move this into a place where it is called once per
569 // BrowserContext creation rather than piggybacking off the default context
570 // creation.
571 // Note: moving this into Get() before partitions_[] is set causes reentrency.
572 if (!resource_context_initialized_) {
573 resource_context_initialized_ = true;
574 InitializeResourceContext(browser_context_);
577 // Check first to avoid memory leak in unittests.
578 if (BrowserThread::IsMessageLoopValid(BrowserThread::IO)) {
579 BrowserThread::PostTask(
580 BrowserThread::IO, FROM_HERE,
581 base::Bind(&ChromeAppCacheService::InitializeOnIOThread,
582 partition->GetAppCacheService(),
583 in_memory ? base::FilePath() :
584 partition->GetPath().Append(kAppCacheDirname),
585 browser_context_->GetResourceContext(),
586 make_scoped_refptr(partition->GetURLRequestContext()),
587 make_scoped_refptr(
588 browser_context_->GetSpecialStoragePolicy())));
590 BrowserThread::PostTask(
591 BrowserThread::IO, FROM_HERE,
592 base::Bind(&CacheStorageContextImpl::SetBlobParametersForCache,
593 partition->GetCacheStorageContext(),
594 make_scoped_refptr(partition->GetURLRequestContext()),
595 make_scoped_refptr(
596 ChromeBlobStorageContext::GetFor(browser_context_))));
598 // We do not call InitializeURLRequestContext() for media contexts because,
599 // other than the HTTP cache, the media contexts share the same backing
600 // objects as their associated "normal" request context. Thus, the previous
601 // call serves to initialize the media request context for this storage
602 // partition as well.
606 } // namespace content