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1 // Copyright (c) 2012 The Chromium Authors. All rights reserved. | 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 | 2 // Use of this source code is governed by a BSD-style license that can be |
3 // found in the LICENSE file. | 3 // found in the LICENSE file. |
4 | 4 |
5 #include "net/http/http_cache.h" | 5 #include "net/http/http_cache.h" |
6 | 6 |
7 #include <algorithm> | 7 #include <algorithm> |
8 #include <utility> | 8 #include <utility> |
9 | 9 |
10 #include "base/bind.h" | 10 #include "base/bind.h" |
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89 true, | 89 true, |
90 thread_, | 90 thread_, |
91 net_log, | 91 net_log, |
92 backend, | 92 backend, |
93 callback); | 93 callback); |
94 } | 94 } |
95 | 95 |
96 //----------------------------------------------------------------------------- | 96 //----------------------------------------------------------------------------- |
97 | 97 |
98 HttpCache::ActiveEntry::ActiveEntry(disk_cache::Entry* entry) | 98 HttpCache::ActiveEntry::ActiveEntry(disk_cache::Entry* entry) |
99 : disk_entry(entry), | 99 : disk_entry(entry) {} |
100 writer(NULL), | |
101 will_process_pending_queue(false), | |
102 doomed(false) { | |
103 } | |
104 | 100 |
105 HttpCache::ActiveEntry::~ActiveEntry() { | 101 HttpCache::ActiveEntry::~ActiveEntry() { |
106 if (disk_entry) { | 102 if (disk_entry) { |
107 disk_entry->Close(); | 103 disk_entry->Close(); |
108 disk_entry = NULL; | 104 disk_entry = nullptr; |
109 } | 105 } |
110 } | 106 } |
111 | 107 |
112 size_t HttpCache::ActiveEntry::EstimateMemoryUsage() const { | 108 size_t HttpCache::ActiveEntry::EstimateMemoryUsage() const { |
113 // Skip |disk_entry| which is tracked in simple_backend_impl; Skip |readers| | 109 // Skip |disk_entry| which is tracked in simple_backend_impl; Skip |readers| |
114 // and |pending_queue| because the Transactions are owned by their respective | 110 // and |add_to_entry_queue| because the Transactions are owned by their |
115 // URLRequestHttpJobs. | 111 // respective URLRequestHttpJobs. |
116 return 0; | 112 return 0; |
117 } | 113 } |
118 | 114 |
119 bool HttpCache::ActiveEntry::HasNoTransactions() { | 115 bool HttpCache::ActiveEntry::HasNoTransactions() { |
120 return !writer && readers.empty() && pending_queue.empty(); | 116 return !writer && readers.empty() && add_to_entry_queue.empty() && |
117 done_headers_queue.empty() && !headers_transaction; | |
118 } | |
119 | |
120 bool HttpCache::ActiveEntry::HasNoActiveTransactions() { | |
121 return !writer && readers.empty() && !headers_transaction; | |
121 } | 122 } |
122 | 123 |
123 //----------------------------------------------------------------------------- | 124 //----------------------------------------------------------------------------- |
124 | 125 |
125 // This structure keeps track of work items that are attempting to create or | 126 // This structure keeps track of work items that are attempting to create or |
126 // open cache entries or the backend itself. | 127 // open cache entries or the backend itself. |
127 struct HttpCache::PendingOp { | 128 struct HttpCache::PendingOp { |
128 PendingOp() : disk_entry(NULL) {} | 129 PendingOp() : disk_entry(NULL) {} |
129 ~PendingOp() {} | 130 ~PendingOp() {} |
130 | 131 |
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353 } | 354 } |
354 } | 355 } |
355 } | 356 } |
356 | 357 |
357 HttpCache::~HttpCache() { | 358 HttpCache::~HttpCache() { |
358 // Transactions should see an invalid cache after this point; otherwise they | 359 // Transactions should see an invalid cache after this point; otherwise they |
359 // could see an inconsistent object (half destroyed). | 360 // could see an inconsistent object (half destroyed). |
360 weak_factory_.InvalidateWeakPtrs(); | 361 weak_factory_.InvalidateWeakPtrs(); |
361 | 362 |
362 // If we have any active entries remaining, then we need to deactivate them. | 363 // If we have any active entries remaining, then we need to deactivate them. |
363 // We may have some pending calls to OnProcessPendingQueue, but since those | 364 // We may have some pending tasks to process queued transactions ,but since |
364 // won't run (due to our destruction), we can simply ignore the corresponding | 365 // those won't run (due to our destruction), we can simply ignore the |
365 // will_process_pending_queue flag. | 366 // corresponding flags. |
366 while (!active_entries_.empty()) { | 367 while (!active_entries_.empty()) { |
367 ActiveEntry* entry = active_entries_.begin()->second.get(); | 368 ActiveEntry* entry = active_entries_.begin()->second.get(); |
368 entry->will_process_pending_queue = false; | 369 entry->will_process_queued_transactions = false; |
369 entry->pending_queue.clear(); | 370 entry->add_to_entry_queue.clear(); |
370 entry->readers.clear(); | 371 entry->readers.clear(); |
371 entry->writer = NULL; | 372 entry->done_headers_queue.clear(); |
373 entry->headers_transaction = nullptr; | |
374 entry->writer = nullptr; | |
372 DeactivateEntry(entry); | 375 DeactivateEntry(entry); |
373 } | 376 } |
374 | 377 |
375 doomed_entries_.clear(); | 378 doomed_entries_.clear(); |
376 | 379 |
377 // Before deleting pending_ops_, we have to make sure that the disk cache is | 380 // Before deleting pending_ops_, we have to make sure that the disk cache is |
378 // done with said operations, or it will attempt to use deleted data. | 381 // done with said operations, or it will attempt to use deleted data. |
379 disk_cache_.reset(); | 382 disk_cache_.reset(); |
380 | 383 |
381 for (auto pending_it = pending_ops_.begin(); pending_it != pending_ops_.end(); | 384 for (auto pending_it = pending_ops_.begin(); pending_it != pending_ops_.end(); |
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622 // We keep track of doomed entries so that we can ensure that they are | 625 // We keep track of doomed entries so that we can ensure that they are |
623 // cleaned up properly when the cache is destroyed. | 626 // cleaned up properly when the cache is destroyed. |
624 ActiveEntry* entry_ptr = entry.get(); | 627 ActiveEntry* entry_ptr = entry.get(); |
625 DCHECK_EQ(0u, doomed_entries_.count(entry_ptr)); | 628 DCHECK_EQ(0u, doomed_entries_.count(entry_ptr)); |
626 doomed_entries_[entry_ptr] = std::move(entry); | 629 doomed_entries_[entry_ptr] = std::move(entry); |
627 | 630 |
628 entry_ptr->disk_entry->Doom(); | 631 entry_ptr->disk_entry->Doom(); |
629 entry_ptr->doomed = true; | 632 entry_ptr->doomed = true; |
630 | 633 |
631 DCHECK(entry_ptr->writer || !entry_ptr->readers.empty() || | 634 DCHECK(entry_ptr->writer || !entry_ptr->readers.empty() || |
632 entry_ptr->will_process_pending_queue); | 635 entry_ptr->headers_transaction || |
636 entry_ptr->will_process_queued_transactions); | |
633 return OK; | 637 return OK; |
634 } | 638 } |
635 | 639 |
636 int HttpCache::AsyncDoomEntry(const std::string& key, Transaction* trans) { | 640 int HttpCache::AsyncDoomEntry(const std::string& key, Transaction* trans) { |
637 std::unique_ptr<WorkItem> item = | 641 std::unique_ptr<WorkItem> item = |
638 base::MakeUnique<WorkItem>(WI_DOOM_ENTRY, trans, nullptr); | 642 base::MakeUnique<WorkItem>(WI_DOOM_ENTRY, trans, nullptr); |
639 PendingOp* pending_op = GetPendingOp(key); | 643 PendingOp* pending_op = GetPendingOp(key); |
640 if (pending_op->writer) { | 644 if (pending_op->writer) { |
641 pending_op->pending_queue.push_back(std::move(item)); | 645 pending_op->pending_queue.push_back(std::move(item)); |
642 return ERR_IO_PENDING; | 646 return ERR_IO_PENDING; |
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678 DCHECK(entry->doomed); | 682 DCHECK(entry->doomed); |
679 DCHECK(entry->HasNoTransactions()); | 683 DCHECK(entry->HasNoTransactions()); |
680 | 684 |
681 auto it = doomed_entries_.find(entry); | 685 auto it = doomed_entries_.find(entry); |
682 DCHECK(it != doomed_entries_.end()); | 686 DCHECK(it != doomed_entries_.end()); |
683 doomed_entries_.erase(it); | 687 doomed_entries_.erase(it); |
684 } | 688 } |
685 | 689 |
686 HttpCache::ActiveEntry* HttpCache::FindActiveEntry(const std::string& key) { | 690 HttpCache::ActiveEntry* HttpCache::FindActiveEntry(const std::string& key) { |
687 auto it = active_entries_.find(key); | 691 auto it = active_entries_.find(key); |
688 return it != active_entries_.end() ? it->second.get() : NULL; | 692 return it != active_entries_.end() ? it->second.get() : nullptr; |
689 } | 693 } |
690 | 694 |
691 HttpCache::ActiveEntry* HttpCache::ActivateEntry( | 695 HttpCache::ActiveEntry* HttpCache::ActivateEntry( |
692 disk_cache::Entry* disk_entry) { | 696 disk_cache::Entry* disk_entry) { |
693 DCHECK(!FindActiveEntry(disk_entry->GetKey())); | 697 DCHECK(!FindActiveEntry(disk_entry->GetKey())); |
694 ActiveEntry* entry = new ActiveEntry(disk_entry); | 698 ActiveEntry* entry = new ActiveEntry(disk_entry); |
695 active_entries_[disk_entry->GetKey()] = base::WrapUnique(entry); | 699 active_entries_[disk_entry->GetKey()] = base::WrapUnique(entry); |
696 return entry; | 700 return entry; |
697 } | 701 } |
698 | 702 |
699 void HttpCache::DeactivateEntry(ActiveEntry* entry) { | 703 void HttpCache::DeactivateEntry(ActiveEntry* entry) { |
700 DCHECK(!entry->will_process_pending_queue); | 704 DCHECK(!entry->will_process_queued_transactions); |
701 DCHECK(!entry->doomed); | 705 DCHECK(!entry->doomed); |
702 DCHECK(entry->disk_entry); | 706 DCHECK(entry->disk_entry); |
703 DCHECK(entry->HasNoTransactions()); | 707 DCHECK(entry->HasNoTransactions()); |
704 | 708 |
705 std::string key = entry->disk_entry->GetKey(); | 709 std::string key = entry->disk_entry->GetKey(); |
706 if (key.empty()) | 710 if (key.empty()) |
707 return SlowDeactivateEntry(entry); | 711 return SlowDeactivateEntry(entry); |
708 | 712 |
709 auto it = active_entries_.find(key); | 713 auto it = active_entries_.find(key); |
710 DCHECK(it != active_entries_.end()); | 714 DCHECK(it != active_entries_.end()); |
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820 } | 824 } |
821 | 825 |
822 void HttpCache::DestroyEntry(ActiveEntry* entry) { | 826 void HttpCache::DestroyEntry(ActiveEntry* entry) { |
823 if (entry->doomed) { | 827 if (entry->doomed) { |
824 FinalizeDoomedEntry(entry); | 828 FinalizeDoomedEntry(entry); |
825 } else { | 829 } else { |
826 DeactivateEntry(entry); | 830 DeactivateEntry(entry); |
827 } | 831 } |
828 } | 832 } |
829 | 833 |
830 int HttpCache::AddTransactionToEntry(ActiveEntry* entry, Transaction* trans) { | 834 int HttpCache::AddTransactionToEntry(ActiveEntry* entry, |
835 Transaction* transaction) { | |
831 DCHECK(entry); | 836 DCHECK(entry); |
832 DCHECK(entry->disk_entry); | 837 DCHECK(entry->disk_entry); |
833 | 838 // Always add a new transaction to the queue to maintain FIFO order. |
834 // We implement a basic reader/writer lock for the disk cache entry. If | 839 entry->add_to_entry_queue.push_back(transaction); |
835 // there is already a writer, then everyone has to wait for the writer to | 840 ProcessQueuedTransactions(entry); |
836 // finish before they can access the cache entry. There can be multiple | 841 return ERR_IO_PENDING; |
837 // readers. | 842 } |
838 // | 843 |
839 // NOTE: If the transaction can only write, then the entry should not be in | 844 int HttpCache::DoneWithResponseHeaders(ActiveEntry* entry, |
840 // use (since any existing entry should have already been doomed). | 845 Transaction* transaction) { |
841 | 846 // If |transaction| is the current writer, do nothing. This can happen for |
842 if (entry->writer || entry->will_process_pending_queue) { | 847 // range requests since they can go back to headers phase after starting to |
843 entry->pending_queue.push_back(trans); | 848 // write. |
844 return ERR_IO_PENDING; | 849 if (entry->writer == transaction) |
845 } | 850 return OK; |
846 | 851 |
847 if (trans->mode() & Transaction::WRITE) { | 852 DCHECK_EQ(entry->headers_transaction, transaction); |
848 // transaction needs exclusive access to the entry | 853 |
849 if (entry->readers.empty()) { | 854 entry->headers_transaction = nullptr; |
850 entry->writer = trans; | 855 |
851 } else { | 856 // If this is not the first transaction in done_headers_queue, it should be a |
852 entry->pending_queue.push_back(trans); | 857 // read-mode transaction. |
853 return ERR_IO_PENDING; | 858 if (!entry->done_headers_queue.empty()) |
854 } | 859 DCHECK(!(transaction->mode() & Transaction::WRITE)); |
jkarlin
2017/04/13 15:05:52
DCHECK(entry->done_headers_queue.empty() || !(tran
shivanisha
2017/04/13 16:54:53
done
| |
855 } else { | 860 |
856 // transaction needs read access to the entry | 861 entry->done_headers_queue.push_back(transaction); |
857 entry->readers.insert(trans); | 862 ProcessQueuedTransactions(entry); |
858 } | 863 return ERR_IO_PENDING; |
859 | 864 } |
860 // We do this before calling EntryAvailable to force any further calls to | 865 |
861 // AddTransactionToEntry to add their transaction to the pending queue, which | 866 void HttpCache::DoneWithEntry(ActiveEntry* entry, |
862 // ensures FIFO ordering. | 867 Transaction* transaction, |
863 if (!entry->writer && !entry->pending_queue.empty()) | |
864 ProcessPendingQueue(entry); | |
865 | |
866 return OK; | |
867 } | |
868 | |
869 void HttpCache::DoneWithEntry(ActiveEntry* entry, Transaction* trans, | |
870 bool cancel) { | 868 bool cancel) { |
871 // If we already posted a task to move on to the next transaction and this was | 869 // Transaction is waiting in the done_headers_queue. |
872 // the writer, there is nothing to cancel. | 870 auto it = std::find(entry->done_headers_queue.begin(), |
873 if (entry->will_process_pending_queue && entry->readers.empty()) | 871 entry->done_headers_queue.end(), transaction); |
874 return; | 872 if (it != entry->done_headers_queue.end()) { |
875 | 873 entry->done_headers_queue.erase(it); |
876 if (entry->writer) { | 874 if (cancel) |
877 DCHECK(trans == entry->writer); | 875 ProcessEntryFailure(entry); |
878 | 876 return; |
877 } | |
878 | |
879 // Transaction is removed in the headers phase. | |
880 if (transaction == entry->headers_transaction) { | |
881 // If the response is not written (cancel is true), consider it a failure. | |
882 DoneWritingToEntry(entry, !cancel, transaction); | |
883 return; | |
884 } | |
885 | |
886 // Transaction is removed in the writing phase. | |
887 if (transaction == entry->writer) { | |
879 // Assume there was a failure. | 888 // Assume there was a failure. |
880 bool success = false; | 889 bool success = false; |
881 if (cancel) { | 890 if (cancel) { |
882 DCHECK(entry->disk_entry); | 891 DCHECK(entry->disk_entry); |
883 // This is a successful operation in the sense that we want to keep the | 892 // This is a successful operation in the sense that we want to keep the |
884 // entry. | 893 // entry. |
885 success = trans->AddTruncatedFlag(); | 894 success = transaction->AddTruncatedFlag(); |
886 // The previous operation may have deleted the entry. | 895 // The previous operation may have deleted the entry. |
887 if (!trans->entry()) | 896 if (!transaction->entry()) |
888 return; | 897 return; |
889 } | 898 } |
890 DoneWritingToEntry(entry, success); | 899 DoneWritingToEntry(entry, success, transaction); |
900 return; | |
901 } | |
902 | |
903 // Transaction is reading from the entry. | |
904 DoneReadingFromEntry(entry, transaction); | |
905 } | |
906 | |
907 void HttpCache::DoneWritingToEntry(ActiveEntry* entry, | |
908 bool success, | |
909 Transaction* transaction) { | |
910 DCHECK(transaction == entry->writer || | |
911 transaction == entry->headers_transaction); | |
912 | |
913 if (transaction == entry->writer) | |
914 entry->writer = nullptr; | |
915 else | |
916 entry->headers_transaction = nullptr; | |
917 | |
918 // If writer fails, all transactions restart the headers_transaction. | |
919 if (!success && entry->headers_transaction) { | |
920 entry->headers_transaction->SetValidatingCannotProceed(); | |
921 entry->headers_transaction = nullptr; | |
922 DCHECK(entry->HasNoActiveTransactions()); | |
923 } | |
924 if (!success) | |
925 ProcessEntryFailure(entry); | |
926 else | |
927 ProcessQueuedTransactions(entry); | |
928 } | |
929 | |
930 void HttpCache::DoneReadingFromEntry(ActiveEntry* entry, | |
931 Transaction* transaction) { | |
932 DCHECK(!entry->writer); | |
933 auto it = entry->readers.find(transaction); | |
934 DCHECK(it != entry->readers.end()); | |
935 entry->readers.erase(it); | |
936 | |
937 ProcessQueuedTransactions(entry); | |
938 } | |
939 | |
940 void HttpCache::RemoveAllQueuedTransactions(ActiveEntry* entry, | |
jkarlin
2017/04/13 15:05:52
Can be in anonymous namespace
shivanisha
2017/04/13 16:54:53
ActiveEntry is private to HttpCache, so cannot mov
| |
941 TransactionList* list) { | |
942 // Process done_headers_queue before add_to_entry_queue to maintain FIFO | |
943 // order. | |
944 for (auto* transaction : entry->done_headers_queue) | |
945 list->push_back(transaction); | |
946 entry->done_headers_queue.clear(); | |
947 | |
948 for (auto* transaction : entry->add_to_entry_queue) | |
949 list->push_back(transaction); | |
950 entry->add_to_entry_queue.clear(); | |
951 } | |
952 | |
953 void HttpCache::ProcessEntryFailure(ActiveEntry* entry) { | |
954 // Failure case is either writer failing to completely write the response to | |
955 // the cache or validating transaction received a non-304 response. | |
956 TransactionList list; | |
957 if (entry->HasNoActiveTransactions() && | |
958 !entry->will_process_queued_transactions) { | |
959 entry->disk_entry->Doom(); | |
960 RemoveAllQueuedTransactions(entry, &list); | |
961 DestroyEntry(entry); | |
891 } else { | 962 } else { |
892 DoneReadingFromEntry(entry, trans); | 963 DoomActiveEntry(entry->disk_entry->GetKey()); |
893 } | 964 RemoveAllQueuedTransactions(entry, &list); |
894 } | 965 } |
895 | 966 // ERR_CACHE_RACE causes the transaction to restart the whole process. |
896 void HttpCache::DoneWritingToEntry(ActiveEntry* entry, bool success) { | 967 for (auto* transaction : list) |
897 DCHECK(entry->readers.empty()); | 968 transaction->io_callback().Run(net::ERR_CACHE_RACE); |
898 | 969 } |
899 entry->writer = NULL; | 970 |
900 | 971 void HttpCache::ProcessQueuedTransactions(ActiveEntry* entry) { |
jkarlin
2017/04/13 15:05:52
This can be in the anonymous namespace. Doing so a
jkarlin
2017/04/13 15:09:20
Ah, to do that you'd need to pass a WeakPtr<HttpCa
| |
901 if (success) { | 972 // Multiple readers may finish with an entry at once, so we want to batch up |
902 ProcessPendingQueue(entry); | 973 // calls to OnProcessQueuedTransactions. This flag also tells us that we |
974 // should not delete the entry before OnProcessQueuedTransactions runs. | |
975 if (entry->will_process_queued_transactions) | |
976 return; | |
977 | |
978 entry->will_process_queued_transactions = true; | |
979 | |
980 // Post a task instead of invoking the io callback of another transaction here | |
981 // to avoid re-entrancy. | |
982 base::ThreadTaskRunnerHandle::Get()->PostTask( | |
983 FROM_HERE, | |
984 base::Bind(&HttpCache::OnProcessQueuedTransactions, GetWeakPtr(), entry)); | |
985 } | |
986 | |
987 void HttpCache::ProcessAddToEntryQueue(ActiveEntry* entry) { | |
988 DCHECK(!entry->add_to_entry_queue.empty()); | |
989 | |
990 // Note the entry may be new or may already have a response body written to | |
991 // it. In both cases, a transaction needs to wait since only one transaction | |
992 // can be in the headers phase at a time. | |
993 if (entry->headers_transaction) { | |
994 return; | |
995 } | |
996 Transaction* transaction = entry->add_to_entry_queue.front(); | |
997 entry->add_to_entry_queue.erase(entry->add_to_entry_queue.begin()); | |
998 entry->headers_transaction = transaction; | |
999 | |
1000 transaction->io_callback().Run(OK); | |
1001 } | |
1002 | |
1003 void HttpCache::ProcessDoneHeadersQueue(ActiveEntry* entry) { | |
1004 DCHECK(!entry->writer); | |
1005 DCHECK(!entry->done_headers_queue.empty()); | |
1006 | |
1007 Transaction* transaction = entry->done_headers_queue.front(); | |
1008 | |
1009 // If this transaction is responsible for writing the response body. | |
1010 if (transaction->mode() & Transaction::WRITE) { | |
1011 entry->writer = transaction; | |
903 } else { | 1012 } else { |
904 DCHECK(!entry->will_process_pending_queue); | 1013 // If a transaction is in front of this queue with only read mode set and |
905 | 1014 // there is no writer, it implies response body is already written, convert |
906 // We failed to create this entry. | 1015 // to a reader. |
907 TransactionList pending_queue; | 1016 auto return_val = entry->readers.insert(transaction); |
908 pending_queue.swap(entry->pending_queue); | 1017 DCHECK_EQ(return_val.second, true); |
909 | 1018 } |
910 entry->disk_entry->Doom(); | 1019 |
911 DestroyEntry(entry); | 1020 // Post another task to give a chance to more transactions to either join |
912 | 1021 // readers or another transaction to start parallel validation. |
913 // We need to do something about these pending entries, which now need to | 1022 ProcessQueuedTransactions(entry); |
914 // be added to a new entry. | 1023 |
915 while (!pending_queue.empty()) { | 1024 entry->done_headers_queue.erase(entry->done_headers_queue.begin()); |
916 // ERR_CACHE_RACE causes the transaction to restart the whole process. | 1025 transaction->io_callback().Run(OK); |
917 pending_queue.front()->io_callback().Run(ERR_CACHE_RACE); | 1026 } |
918 pending_queue.pop_front(); | 1027 |
919 } | 1028 bool HttpCache::CanTransactionWriteResponseHeaders(ActiveEntry* entry, |
920 } | 1029 Transaction* transaction, |
921 } | 1030 int response_code) const { |
922 | 1031 if (transaction != entry->headers_transaction) |
923 void HttpCache::DoneReadingFromEntry(ActiveEntry* entry, Transaction* trans) { | 1032 return false; |
924 DCHECK(!entry->writer); | 1033 |
925 | 1034 if (!(transaction->mode() & Transaction::WRITE)) |
926 auto it = entry->readers.find(trans); | 1035 return false; |
927 DCHECK(it != entry->readers.end()); | 1036 |
928 | 1037 // If its not a match then check if it is the transaction responsible for |
929 entry->readers.erase(it); | 1038 // writing the response body. |
930 | 1039 if (response_code != 304) { |
931 ProcessPendingQueue(entry); | 1040 return !entry->writer && entry->done_headers_queue.empty() && |
932 } | 1041 entry->readers.empty(); |
933 | 1042 } |
934 void HttpCache::ConvertWriterToReader(ActiveEntry* entry) { | 1043 |
935 DCHECK(entry->writer); | 1044 return true; |
936 DCHECK(entry->writer->mode() == Transaction::READ_WRITE); | 1045 } |
937 DCHECK(entry->readers.empty()); | 1046 |
938 | 1047 bool HttpCache::IsTransactionWritingIncomplete( |
939 Transaction* trans = entry->writer; | 1048 ActiveEntry* entry, |
940 | 1049 Transaction* transaction, |
941 entry->writer = NULL; | 1050 const std::string& method) const { |
942 entry->readers.insert(trans); | 1051 if (transaction == entry->writer) |
943 | 1052 return true; |
944 ProcessPendingQueue(entry); | 1053 |
945 } | 1054 if (method == "HEAD" || method == "DELETE") |
946 | 1055 return false; |
1056 | |
1057 // Check if transaction is about to start writing to the cache. | |
1058 | |
1059 // Transaction's mode may have been set to NONE if StopCaching was invoked. | |
1060 if (!(transaction->mode() & Transaction::WRITE || | |
1061 transaction->mode() == Transaction::NONE)) { | |
1062 return false; | |
1063 } | |
1064 | |
1065 // If a transaction is completing headers or done with headers phase with | |
1066 // Write mode then it should be the future writer. Just checking the front of | |
jkarlin
2017/04/13 15:05:52
lowercase Write
shivanisha
2017/04/13 16:54:53
done
| |
1067 // done_headers_queue since the rest should anyways be READ mode transactions | |
1068 // as they would be a result of validation match. | |
1069 if (transaction == entry->headers_transaction || | |
1070 transaction == entry->done_headers_queue.front()) { | |
1071 return true; | |
1072 } | |
1073 | |
1074 return false; | |
1075 } | |
947 LoadState HttpCache::GetLoadStateForPendingTransaction( | 1076 LoadState HttpCache::GetLoadStateForPendingTransaction( |
948 const Transaction* trans) { | 1077 const Transaction* trans) { |
949 auto i = active_entries_.find(trans->key()); | 1078 auto i = active_entries_.find(trans->key()); |
950 if (i == active_entries_.end()) { | 1079 if (i == active_entries_.end()) { |
951 // If this is really a pending transaction, and it is not part of | 1080 // If this is really a pending transaction, and it is not part of |
952 // active_entries_, we should be creating the backend or the entry. | 1081 // active_entries_, we should be creating the backend or the entry. |
953 return LOAD_STATE_WAITING_FOR_CACHE; | 1082 return LOAD_STATE_WAITING_FOR_CACHE; |
954 } | 1083 } |
955 | 1084 |
956 Transaction* writer = i->second->writer; | 1085 Transaction* writer = i->second->writer; |
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984 | 1113 |
985 for (auto k = doomed_entries_.begin(); k != doomed_entries_.end() && !found; | 1114 for (auto k = doomed_entries_.begin(); k != doomed_entries_.end() && !found; |
986 ++k) { | 1115 ++k) { |
987 found = RemovePendingTransactionFromEntry(k->first, trans); | 1116 found = RemovePendingTransactionFromEntry(k->first, trans); |
988 } | 1117 } |
989 | 1118 |
990 DCHECK(found) << "Pending transaction not found"; | 1119 DCHECK(found) << "Pending transaction not found"; |
991 } | 1120 } |
992 | 1121 |
993 bool HttpCache::RemovePendingTransactionFromEntry(ActiveEntry* entry, | 1122 bool HttpCache::RemovePendingTransactionFromEntry(ActiveEntry* entry, |
994 Transaction* trans) { | 1123 Transaction* transaction) { |
995 TransactionList& pending_queue = entry->pending_queue; | 1124 TransactionList& add_to_entry_queue = entry->add_to_entry_queue; |
996 | 1125 |
997 auto j = find(pending_queue.begin(), pending_queue.end(), trans); | 1126 auto j = |
998 if (j == pending_queue.end()) | 1127 find(add_to_entry_queue.begin(), add_to_entry_queue.end(), transaction); |
1128 if (j == add_to_entry_queue.end()) | |
999 return false; | 1129 return false; |
1000 | 1130 |
1001 pending_queue.erase(j); | 1131 add_to_entry_queue.erase(j); |
1002 return true; | 1132 return true; |
1003 } | 1133 } |
1004 | 1134 |
1005 bool HttpCache::RemovePendingTransactionFromPendingOp(PendingOp* pending_op, | 1135 bool HttpCache::RemovePendingTransactionFromPendingOp(PendingOp* pending_op, |
1006 Transaction* trans) { | 1136 Transaction* trans) { |
1007 if (pending_op->writer->Matches(trans)) { | 1137 if (pending_op->writer->Matches(trans)) { |
1008 pending_op->writer->ClearTransaction(); | 1138 pending_op->writer->ClearTransaction(); |
1009 pending_op->writer->ClearEntry(); | 1139 pending_op->writer->ClearEntry(); |
1010 return true; | 1140 return true; |
1011 } | 1141 } |
1012 WorkItemList& pending_queue = pending_op->pending_queue; | 1142 WorkItemList& pending_queue = pending_op->pending_queue; |
1013 | 1143 |
1014 for (auto it = pending_queue.begin(); it != pending_queue.end(); ++it) { | 1144 for (auto it = pending_queue.begin(); it != pending_queue.end(); ++it) { |
1015 if ((*it)->Matches(trans)) { | 1145 if ((*it)->Matches(trans)) { |
1016 pending_queue.erase(it); | 1146 pending_queue.erase(it); |
1017 return true; | 1147 return true; |
1018 } | 1148 } |
1019 } | 1149 } |
1020 return false; | 1150 return false; |
1021 } | 1151 } |
1022 | 1152 |
1023 void HttpCache::ProcessPendingQueue(ActiveEntry* entry) { | 1153 void HttpCache::OnProcessQueuedTransactions(ActiveEntry* entry) { |
1024 // Multiple readers may finish with an entry at once, so we want to batch up | 1154 entry->will_process_queued_transactions = false; |
1025 // calls to OnProcessPendingQueue. This flag also tells us that we should | |
1026 // not delete the entry before OnProcessPendingQueue runs. | |
1027 if (entry->will_process_pending_queue) | |
1028 return; | |
1029 entry->will_process_pending_queue = true; | |
1030 | 1155 |
1031 base::ThreadTaskRunnerHandle::Get()->PostTask( | 1156 // Note that this function should only invoke one transaction's IO callback |
1032 FROM_HERE, | 1157 // since its possible for IO callbacks' consumers to destroy the cache/entry. |
1033 base::Bind(&HttpCache::OnProcessPendingQueue, GetWeakPtr(), entry)); | |
1034 } | |
1035 | |
1036 void HttpCache::OnProcessPendingQueue(ActiveEntry* entry) { | |
1037 entry->will_process_pending_queue = false; | |
1038 DCHECK(!entry->writer); | |
1039 | 1158 |
1040 // If no one is interested in this entry, then we can deactivate it. | 1159 // If no one is interested in this entry, then we can deactivate it. |
1041 if (entry->HasNoTransactions()) { | 1160 if (entry->HasNoTransactions()) { |
1042 DestroyEntry(entry); | 1161 DestroyEntry(entry); |
1043 return; | 1162 return; |
1044 } | 1163 } |
1045 | 1164 |
1046 if (entry->pending_queue.empty()) | 1165 if (entry->done_headers_queue.empty() && entry->add_to_entry_queue.empty()) |
1047 return; | 1166 return; |
1048 | 1167 |
1049 // Promote next transaction from the pending queue. | 1168 // To maintain FIFO order of transactions, done_headers_queue should be |
1050 Transaction* next = entry->pending_queue.front(); | 1169 // checked for processing before add_to_entry_queue. |
1051 if ((next->mode() & Transaction::WRITE) && !entry->readers.empty()) | |
1052 return; // Have to wait. | |
1053 | 1170 |
1054 entry->pending_queue.erase(entry->pending_queue.begin()); | 1171 // If another transaction is writing the response, let validated transactions |
1172 // wait till the response is complete. If the response is not yet started, the | |
1173 // done_headers_queue transaction should start writing it. | |
1174 if (!entry->writer && !entry->done_headers_queue.empty()) { | |
1175 ProcessDoneHeadersQueue(entry); | |
1176 return; | |
1177 } | |
1055 | 1178 |
1056 int rv = AddTransactionToEntry(entry, next); | 1179 if (!entry->add_to_entry_queue.empty()) |
1057 if (rv != ERR_IO_PENDING) { | 1180 ProcessAddToEntryQueue(entry); |
1058 next->io_callback().Run(rv); | |
1059 } | |
1060 } | 1181 } |
1061 | 1182 |
1062 void HttpCache::OnIOComplete(int result, PendingOp* pending_op) { | 1183 void HttpCache::OnIOComplete(int result, PendingOp* pending_op) { |
1063 WorkItemOperation op = pending_op->writer->operation(); | 1184 WorkItemOperation op = pending_op->writer->operation(); |
1064 | 1185 |
1065 // Completing the creation of the backend is simpler than the other cases. | 1186 // Completing the creation of the backend is simpler than the other cases. |
1066 if (op == WI_CREATE_BACKEND) | 1187 if (op == WI_CREATE_BACKEND) |
1067 return OnBackendCreated(result, pending_op); | 1188 return OnBackendCreated(result, pending_op); |
1068 | 1189 |
1069 std::unique_ptr<WorkItem> item = std::move(pending_op->writer); | 1190 std::unique_ptr<WorkItem> item = std::move(pending_op->writer); |
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1196 building_backend_ = false; | 1317 building_backend_ = false; |
1197 DeletePendingOp(pending_op); | 1318 DeletePendingOp(pending_op); |
1198 } | 1319 } |
1199 | 1320 |
1200 // The cache may be gone when we return from the callback. | 1321 // The cache may be gone when we return from the callback. |
1201 if (!item->DoCallback(result, disk_cache_.get())) | 1322 if (!item->DoCallback(result, disk_cache_.get())) |
1202 item->NotifyTransaction(result, NULL); | 1323 item->NotifyTransaction(result, NULL); |
1203 } | 1324 } |
1204 | 1325 |
1205 } // namespace net | 1326 } // namespace net |
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