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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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621 // We keep track of doomed entries so that we can ensure that they are | 624 // We keep track of doomed entries so that we can ensure that they are |
622 // cleaned up properly when the cache is destroyed. | 625 // cleaned up properly when the cache is destroyed. |
623 ActiveEntry* entry_ptr = entry.get(); | 626 ActiveEntry* entry_ptr = entry.get(); |
624 DCHECK_EQ(0u, doomed_entries_.count(entry_ptr)); | 627 DCHECK_EQ(0u, doomed_entries_.count(entry_ptr)); |
625 doomed_entries_[entry_ptr] = std::move(entry); | 628 doomed_entries_[entry_ptr] = std::move(entry); |
626 | 629 |
627 entry_ptr->disk_entry->Doom(); | 630 entry_ptr->disk_entry->Doom(); |
628 entry_ptr->doomed = true; | 631 entry_ptr->doomed = true; |
629 | 632 |
630 DCHECK(entry_ptr->writer || !entry_ptr->readers.empty() || | 633 DCHECK(entry_ptr->writer || !entry_ptr->readers.empty() || |
631 entry_ptr->will_process_pending_queue); | 634 entry_ptr->headers_transaction || |
635 entry_ptr->will_process_queued_transactions); | |
632 return OK; | 636 return OK; |
633 } | 637 } |
634 | 638 |
635 int HttpCache::AsyncDoomEntry(const std::string& key, Transaction* trans) { | 639 int HttpCache::AsyncDoomEntry(const std::string& key, Transaction* trans) { |
636 std::unique_ptr<WorkItem> item = | 640 std::unique_ptr<WorkItem> item = |
637 base::MakeUnique<WorkItem>(WI_DOOM_ENTRY, trans, nullptr); | 641 base::MakeUnique<WorkItem>(WI_DOOM_ENTRY, trans, nullptr); |
638 PendingOp* pending_op = GetPendingOp(key); | 642 PendingOp* pending_op = GetPendingOp(key); |
639 if (pending_op->writer) { | 643 if (pending_op->writer) { |
640 pending_op->pending_queue.push_back(std::move(item)); | 644 pending_op->pending_queue.push_back(std::move(item)); |
641 return ERR_IO_PENDING; | 645 return ERR_IO_PENDING; |
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677 DCHECK(entry->doomed); | 681 DCHECK(entry->doomed); |
678 DCHECK(entry->HasNoTransactions()); | 682 DCHECK(entry->HasNoTransactions()); |
679 | 683 |
680 auto it = doomed_entries_.find(entry); | 684 auto it = doomed_entries_.find(entry); |
681 DCHECK(it != doomed_entries_.end()); | 685 DCHECK(it != doomed_entries_.end()); |
682 doomed_entries_.erase(it); | 686 doomed_entries_.erase(it); |
683 } | 687 } |
684 | 688 |
685 HttpCache::ActiveEntry* HttpCache::FindActiveEntry(const std::string& key) { | 689 HttpCache::ActiveEntry* HttpCache::FindActiveEntry(const std::string& key) { |
686 auto it = active_entries_.find(key); | 690 auto it = active_entries_.find(key); |
687 return it != active_entries_.end() ? it->second.get() : NULL; | 691 return it != active_entries_.end() ? it->second.get() : nullptr; |
688 } | 692 } |
689 | 693 |
690 HttpCache::ActiveEntry* HttpCache::ActivateEntry( | 694 HttpCache::ActiveEntry* HttpCache::ActivateEntry( |
691 disk_cache::Entry* disk_entry) { | 695 disk_cache::Entry* disk_entry) { |
692 DCHECK(!FindActiveEntry(disk_entry->GetKey())); | 696 DCHECK(!FindActiveEntry(disk_entry->GetKey())); |
693 ActiveEntry* entry = new ActiveEntry(disk_entry); | 697 ActiveEntry* entry = new ActiveEntry(disk_entry); |
694 active_entries_[disk_entry->GetKey()] = base::WrapUnique(entry); | 698 active_entries_[disk_entry->GetKey()] = base::WrapUnique(entry); |
695 return entry; | 699 return entry; |
696 } | 700 } |
697 | 701 |
698 void HttpCache::DeactivateEntry(ActiveEntry* entry) { | 702 void HttpCache::DeactivateEntry(ActiveEntry* entry) { |
699 DCHECK(!entry->will_process_pending_queue); | 703 DCHECK(!entry->will_process_queued_transactions); |
700 DCHECK(!entry->doomed); | 704 DCHECK(!entry->doomed); |
701 DCHECK(entry->disk_entry); | 705 DCHECK(entry->disk_entry); |
702 DCHECK(entry->HasNoTransactions()); | 706 DCHECK(entry->HasNoTransactions()); |
703 | 707 |
704 std::string key = entry->disk_entry->GetKey(); | 708 std::string key = entry->disk_entry->GetKey(); |
705 if (key.empty()) | 709 if (key.empty()) |
706 return SlowDeactivateEntry(entry); | 710 return SlowDeactivateEntry(entry); |
707 | 711 |
708 auto it = active_entries_.find(key); | 712 auto it = active_entries_.find(key); |
709 DCHECK(it != active_entries_.end()); | 713 DCHECK(it != active_entries_.end()); |
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819 } | 823 } |
820 | 824 |
821 void HttpCache::DestroyEntry(ActiveEntry* entry) { | 825 void HttpCache::DestroyEntry(ActiveEntry* entry) { |
822 if (entry->doomed) { | 826 if (entry->doomed) { |
823 FinalizeDoomedEntry(entry); | 827 FinalizeDoomedEntry(entry); |
824 } else { | 828 } else { |
825 DeactivateEntry(entry); | 829 DeactivateEntry(entry); |
826 } | 830 } |
827 } | 831 } |
828 | 832 |
829 int HttpCache::AddTransactionToEntry(ActiveEntry* entry, Transaction* trans) { | 833 int HttpCache::AddTransactionToEntry(ActiveEntry* entry, |
834 Transaction* transaction) { | |
830 DCHECK(entry); | 835 DCHECK(entry); |
831 DCHECK(entry->disk_entry); | 836 DCHECK(entry->disk_entry); |
832 | 837 // Always add a new transaction to the queue to maintain FIFO order. |
833 // We implement a basic reader/writer lock for the disk cache entry. If | 838 entry->add_to_entry_queue.push_back(transaction); |
834 // there is already a writer, then everyone has to wait for the writer to | 839 ProcessQueuedTransactions(entry); |
835 // finish before they can access the cache entry. There can be multiple | 840 return ERR_IO_PENDING; |
836 // readers. | 841 } |
837 // | 842 |
838 // NOTE: If the transaction can only write, then the entry should not be in | 843 int HttpCache::DoneResponseHeaders(ActiveEntry* entry, |
839 // use (since any existing entry should have already been doomed). | 844 Transaction* transaction, |
840 | 845 bool is_match) { |
841 if (entry->writer || entry->will_process_pending_queue) { | 846 DCHECK_EQ(entry->headers_transaction, transaction); |
842 entry->pending_queue.push_back(trans); | 847 entry->headers_transaction = nullptr; |
843 return ERR_IO_PENDING; | 848 |
844 } | 849 if (!is_match) { |
845 | 850 // Doom or destroy this entry based on whether it has active consumers. |
846 if (trans->mode() & Transaction::WRITE) { | 851 ProcessEntryFailure(entry); |
847 // transaction needs exclusive access to the entry | 852 return OK; |
848 if (entry->readers.empty()) { | 853 } |
849 entry->writer = trans; | 854 |
855 entry->done_headers_queue.push_back(transaction); | |
856 ProcessQueuedTransactions(entry); | |
857 return ERR_IO_PENDING; | |
858 } | |
859 | |
860 void HttpCache::RemoveAllQueuedTransactions(ActiveEntry* entry, | |
861 TransactionList* list) { | |
862 // Process done_headers_queue before add_to_entry_queue to maintain FIFO | |
863 // order. | |
864 for (auto* transaction : entry->done_headers_queue) | |
865 list->push_back(transaction); | |
866 entry->done_headers_queue.clear(); | |
867 | |
868 for (auto* transaction : entry->add_to_entry_queue) | |
869 list->push_back(transaction); | |
870 entry->add_to_entry_queue.clear(); | |
871 } | |
872 | |
873 void HttpCache::ProcessEntryFailure(ActiveEntry* entry) { | |
874 // Failure case is either writer failing to completely write the response to | |
875 // the cache or validating transaction received a non-304 response. | |
876 TransactionList list; | |
877 if (entry->HasNoActiveTransactions() && | |
878 !entry->will_process_queued_transactions) { | |
879 entry->disk_entry->Doom(); | |
880 RemoveAllQueuedTransactions(entry, &list); | |
881 DestroyEntry(entry); | |
882 } else { | |
883 DoomActiveEntry(entry->disk_entry->GetKey()); | |
884 RemoveAllQueuedTransactions(entry, &list); | |
885 } | |
886 // ERR_CACHE_RACE causes the transaction to restart the whole process. | |
887 for (auto* transaction : list) | |
888 transaction->io_callback().Run(net::ERR_CACHE_RACE); | |
889 } | |
890 | |
891 void HttpCache::ProcessQueuedTransactions(ActiveEntry* entry) { | |
892 // Multiple readers may finish with an entry at once, so we want to batch up | |
893 // calls to OnProcessQueuedTransactions. This flag also tells us that we | |
894 // should not delete the entry before OnProcessQueuedTransactions runs. | |
895 if (entry->will_process_queued_transactions) | |
896 return; | |
897 | |
898 entry->will_process_queued_transactions = true; | |
899 | |
900 // Post a task instead of invoking the io callback of another transaction here | |
901 // to avoid re-entrancy. | |
902 base::ThreadTaskRunnerHandle::Get()->PostTask( | |
903 FROM_HERE, | |
904 base::Bind(&HttpCache::OnProcessQueuedTransactions, GetWeakPtr(), entry)); | |
905 } | |
906 | |
907 void HttpCache::OnProcessQueuedTransactions(ActiveEntry* entry) { | |
908 entry->will_process_queued_transactions = false; | |
909 | |
910 // If no one is interested in this entry, then we can deactivate it. | |
911 if (entry->HasNoTransactions()) { | |
912 DestroyEntry(entry); | |
913 return; | |
914 } | |
915 | |
916 if (entry->done_headers_queue.empty() && entry->add_to_entry_queue.empty()) | |
917 return; | |
918 | |
919 // To maintain FIFO order of transactions, done_headers_queue should be | |
920 // processed first, and then add_to_entry_queue. | |
921 // If another transaction is writing the response, let validated transactions | |
922 // wait till the response is complete. If the response is not yet started, the | |
923 // done_headers_queue transaction should start writing it. | |
924 if (!entry->writer && !entry->done_headers_queue.empty()) { | |
925 ProcessDoneHeadersTransaction(entry); | |
926 return; | |
927 } | |
928 | |
929 if (!entry->add_to_entry_queue.empty()) | |
930 ProcessAddToEntryTransaction(entry); | |
931 } | |
932 | |
933 void HttpCache::ProcessAddToEntryTransaction(ActiveEntry* entry) { | |
934 if (entry->headers_transaction) { | |
935 // Note the entry may be new or may already have a response body written to | |
936 // it. In both cases, a transaction with write mode set, needs to wait | |
937 // because only one transaction is allowed to be validating at a time. | |
938 // If transaction is read-only and entry is not yet complete, then it | |
939 // needs to wait. If entry is complete, it needs to wait because its | |
940 // possible that the headers_transaction dooms the entry if its not a match. | |
941 return; | |
942 } | |
943 | |
944 Transaction* transaction = entry->add_to_entry_queue.front(); | |
945 if (entry->writer) { | |
946 // A transaction either starts headers phase or waits. | |
947 if (transaction->mode() & Transaction::WRITE) { | |
948 entry->headers_transaction = transaction; | |
850 } else { | 949 } else { |
851 entry->pending_queue.push_back(trans); | 950 return; |
852 return ERR_IO_PENDING; | |
853 } | 951 } |
854 } else { | 952 } else { |
855 // transaction needs read access to the entry | 953 // This state may be reached either during the start of an entry or when the |
856 entry->readers.insert(trans); | 954 // response is written. |
857 } | 955 if (transaction->mode() & Transaction::WRITE) { |
858 | 956 entry->headers_transaction = transaction; |
859 // We do this before calling EntryAvailable to force any further calls to | 957 } else { |
860 // AddTransactionToEntry to add their transaction to the pending queue, which | 958 // A read-only transaction can start reading the response. |
861 // ensures FIFO ordering. | 959 // If a read transaction is here, then it has to be an already created |
862 if (!entry->writer && !entry->pending_queue.empty()) | 960 // entry as the other case is already handled in the Transaction state |
863 ProcessPendingQueue(entry); | 961 // machine. |
864 | 962 entry->readers.insert(transaction); |
865 return OK; | 963 |
866 } | 964 // More readers can join too. |
867 | 965 ProcessQueuedTransactions(entry); |
Randy Smith (Not in Mondays)
2017/03/30 19:18:05
Is it reasonable to avoid another thread hop here
shivanisha
2017/03/31 17:47:05
Looping here will mean that the control flow goes
Randy Smith (Not in Mondays)
2017/03/31 19:26:12
Why is that a useful invariant?
shivanisha
2017/04/03 20:16:48
As discussed f2f, I have preferred to keep the pos
| |
868 void HttpCache::DoneWithEntry(ActiveEntry* entry, Transaction* trans, | 966 } |
967 } | |
968 | |
969 entry->add_to_entry_queue.erase(entry->add_to_entry_queue.begin()); | |
Randy Smith (Not in Mondays)
2017/03/30 19:18:05
Would it be reasonable to rewrite the above so tha
shivanisha
2017/03/31 17:47:05
Done.
| |
970 transaction->io_callback().Run(OK); | |
971 } | |
972 | |
973 void HttpCache::ProcessDoneHeadersTransaction(ActiveEntry* entry) { | |
974 DCHECK(!entry->writer && !entry->done_headers_queue.empty()); | |
975 Transaction* transaction = entry->done_headers_queue.front(); | |
976 // If this transaction is responsible for writing the response body. | |
977 if (transaction->mode() & Transaction::WRITE) { | |
978 DCHECK_EQ(entry->done_headers_queue.size(), (size_t)1); | |
979 entry->writer = transaction; | |
980 } else { | |
981 // Response body is already written, convert to a reader. | |
Randy Smith (Not in Mondays)
2017/03/30 19:18:05
Isn't the response body about the state of the Act
shivanisha
2017/03/31 17:47:05
This comment here signifies that since we are in P
| |
982 auto return_val = entry->readers.insert(transaction); | |
983 DCHECK_EQ(return_val.second, true); | |
984 } | |
985 // Post another task to give a chance to more transactions to either join | |
986 // readers or another transaction to start parallel validation. | |
987 ProcessQueuedTransactions(entry); | |
Randy Smith (Not in Mondays)
2017/03/30 19:18:05
Given that we're already a PostTask away from the
shivanisha
2017/03/31 17:47:05
Looping here will mean that the control flow goes
| |
988 entry->done_headers_queue.erase(entry->done_headers_queue.begin()); | |
989 transaction->io_callback().Run(OK); | |
990 } | |
991 | |
992 bool HttpCache::IsCancelResponseBody(ActiveEntry* entry, | |
jkarlin
2017/03/30 14:58:14
The name IsCancelResponseBody doesn't make sense t
shivanisha
2017/03/31 17:47:05
Actually, what this function needs to return is th
| |
993 Transaction* transaction, | |
994 const std::string& method) { | |
995 bool cancel = (method != "HEAD"); | |
jkarlin
2017/03/30 14:58:14
The cancel variable is unnecessary and adds confus
shivanisha
2017/04/03 20:16:48
done
| |
996 | |
997 if (!cancel) | |
998 return false; | |
999 | |
jkarlin
2017/03/30 14:58:14
It seems like this function shouldn't be necessary
shivanisha
2017/03/31 17:47:05
Let's see... a transaction can tell above 1) and 2
| |
1000 if (transaction == entry->writer) | |
1001 return cancel; | |
1002 | |
1003 // Transaction's mode may have been set to NONE if StopCaching was invoked. | |
1004 // Check if transaction was about to start writing to the cache. | |
1005 cancel &= (transaction->mode() & Transaction::WRITE || | |
1006 transaction->mode() == Transaction::NONE); | |
1007 | |
1008 if (!cancel) | |
1009 return false; | |
1010 | |
1011 if (transaction == entry->headers_transaction) { | |
1012 cancel &= (!entry->writer); | |
1013 return cancel; | |
1014 } | |
1015 | |
1016 if (!entry->done_headers_queue.empty()) { | |
1017 auto i = std::find(entry->done_headers_queue.begin(), | |
1018 entry->done_headers_queue.end(), transaction); | |
1019 if (i != entry->done_headers_queue.end()) { | |
1020 cancel &= (!entry->writer); | |
1021 return cancel; | |
1022 } | |
1023 } | |
1024 | |
1025 return false; | |
1026 } | |
1027 | |
1028 void HttpCache::DoneWithEntry(ActiveEntry* entry, | |
1029 Transaction* transaction, | |
869 bool cancel) { | 1030 bool cancel) { |
870 // If we already posted a task to move on to the next transaction and this was | 1031 // Transaction is waiting in the done_headers_queue. |
871 // the writer, there is nothing to cancel. | 1032 if (!entry->done_headers_queue.empty()) { |
Randy Smith (Not in Mondays)
2017/03/30 19:18:05
I think you can leave the outer conditional off wi
shivanisha
2017/03/31 17:47:05
Removed.
| |
872 if (entry->will_process_pending_queue && entry->readers.empty()) | 1033 auto i = std::find(entry->done_headers_queue.begin(), |
873 return; | 1034 entry->done_headers_queue.end(), transaction); |
874 | 1035 if (i != entry->done_headers_queue.end()) { |
875 if (entry->writer) { | 1036 entry->done_headers_queue.erase(i); |
876 DCHECK(trans == entry->writer); | 1037 if (cancel) |
877 | 1038 ProcessEntryFailure(entry); |
1039 return; | |
1040 } | |
1041 } | |
1042 | |
1043 // Transaction is removed in the headers phase. | |
1044 if (transaction == entry->headers_transaction) { | |
1045 // If the response is not written (cancel is true), consider it a failure. | |
1046 DoneWritingToEntry(entry, !cancel, transaction); | |
1047 return; | |
1048 } | |
1049 | |
1050 // Transaction is removed in the writing phase. | |
1051 if (transaction == entry->writer) { | |
878 // Assume there was a failure. | 1052 // Assume there was a failure. |
879 bool success = false; | 1053 bool success = false; |
880 if (cancel) { | 1054 if (cancel) { |
881 DCHECK(entry->disk_entry); | 1055 DCHECK(entry->disk_entry); |
882 // This is a successful operation in the sense that we want to keep the | 1056 // This is a successful operation in the sense that we want to keep the |
883 // entry. | 1057 // entry. |
884 success = trans->AddTruncatedFlag(); | 1058 success = transaction->AddTruncatedFlag(); |
885 // The previous operation may have deleted the entry. | 1059 // The previous operation may have deleted the entry. |
886 if (!trans->entry()) | 1060 if (!transaction->entry()) |
887 return; | 1061 return; |
888 } | 1062 } |
889 DoneWritingToEntry(entry, success); | 1063 DoneWritingToEntry(entry, success, transaction); |
890 } else { | 1064 return; |
891 DoneReadingFromEntry(entry, trans); | 1065 } |
892 } | 1066 |
893 } | 1067 // Transaction is reading from the entry. |
894 | 1068 DoneReadingFromEntry(entry, transaction); |
895 void HttpCache::DoneWritingToEntry(ActiveEntry* entry, bool success) { | 1069 } |
896 DCHECK(entry->readers.empty()); | 1070 |
897 | 1071 void HttpCache::DoneWritingToEntry(ActiveEntry* entry, |
898 entry->writer = NULL; | 1072 bool success, |
899 | 1073 Transaction* transaction) { |
900 if (success) { | 1074 DCHECK(transaction == entry->writer || |
901 ProcessPendingQueue(entry); | 1075 transaction == entry->headers_transaction); |
902 } else { | 1076 |
903 DCHECK(!entry->will_process_pending_queue); | 1077 // Transaction is done writing to entry in the response body phase. |
904 | 1078 if (transaction == entry->writer) |
905 // We failed to create this entry. | 1079 entry->writer = nullptr; |
906 TransactionList pending_queue; | 1080 else |
907 pending_queue.swap(entry->pending_queue); | 1081 entry->headers_transaction = nullptr; |
908 | 1082 |
909 entry->disk_entry->Doom(); | 1083 // If writer fails, all transactions should fail. |
Randy Smith (Not in Mondays)
2017/03/30 19:18:05
All transactions? This is just failing the header
shivanisha
2017/03/31 17:47:05
Changed the comment to : "... all transactions sho
Randy Smith (Not in Mondays)
2017/03/31 19:26:12
Still confused, though maybe it's just about place
shivanisha
2017/04/03 20:16:48
Ah I see, changed the comment to just mention head
| |
910 DestroyEntry(entry); | 1084 if (!success && entry->headers_transaction) { |
911 | 1085 entry->headers_transaction->SetValidatingCannotProceed(); |
912 // We need to do something about these pending entries, which now need to | 1086 entry->headers_transaction = nullptr; |
913 // be added to a new entry. | 1087 DCHECK(entry->HasNoActiveTransactions()); |
914 while (!pending_queue.empty()) { | 1088 } |
915 // ERR_CACHE_RACE causes the transaction to restart the whole process. | 1089 if (!success) |
916 pending_queue.front()->io_callback().Run(ERR_CACHE_RACE); | 1090 ProcessEntryFailure(entry); |
917 pending_queue.pop_front(); | 1091 else |
918 } | 1092 ProcessQueuedTransactions(entry); |
919 } | 1093 } |
920 } | 1094 |
921 | 1095 void HttpCache::DoneReadingFromEntry(ActiveEntry* entry, |
922 void HttpCache::DoneReadingFromEntry(ActiveEntry* entry, Transaction* trans) { | 1096 Transaction* transaction) { |
923 DCHECK(!entry->writer); | 1097 DCHECK(!entry->writer); |
924 | 1098 auto it = entry->readers.find(transaction); |
925 auto it = entry->readers.find(trans); | |
926 DCHECK(it != entry->readers.end()); | 1099 DCHECK(it != entry->readers.end()); |
927 | |
928 entry->readers.erase(it); | 1100 entry->readers.erase(it); |
929 | 1101 |
930 ProcessPendingQueue(entry); | 1102 ProcessQueuedTransactions(entry); |
931 } | |
932 | |
933 void HttpCache::ConvertWriterToReader(ActiveEntry* entry) { | |
934 DCHECK(entry->writer); | |
935 DCHECK(entry->writer->mode() == Transaction::READ_WRITE); | |
936 DCHECK(entry->readers.empty()); | |
937 | |
938 Transaction* trans = entry->writer; | |
939 | |
940 entry->writer = NULL; | |
941 entry->readers.insert(trans); | |
942 | |
943 ProcessPendingQueue(entry); | |
944 } | 1103 } |
945 | 1104 |
946 LoadState HttpCache::GetLoadStateForPendingTransaction( | 1105 LoadState HttpCache::GetLoadStateForPendingTransaction( |
947 const Transaction* trans) { | 1106 const Transaction* trans) { |
948 auto i = active_entries_.find(trans->key()); | 1107 auto i = active_entries_.find(trans->key()); |
949 if (i == active_entries_.end()) { | 1108 if (i == active_entries_.end()) { |
950 // If this is really a pending transaction, and it is not part of | 1109 // If this is really a pending transaction, and it is not part of |
951 // active_entries_, we should be creating the backend or the entry. | 1110 // active_entries_, we should be creating the backend or the entry. |
952 return LOAD_STATE_WAITING_FOR_CACHE; | 1111 return LOAD_STATE_WAITING_FOR_CACHE; |
953 } | 1112 } |
(...skipping 29 matching lines...) Expand all Loading... | |
983 | 1142 |
984 for (auto k = doomed_entries_.begin(); k != doomed_entries_.end() && !found; | 1143 for (auto k = doomed_entries_.begin(); k != doomed_entries_.end() && !found; |
985 ++k) { | 1144 ++k) { |
986 found = RemovePendingTransactionFromEntry(k->first, trans); | 1145 found = RemovePendingTransactionFromEntry(k->first, trans); |
987 } | 1146 } |
988 | 1147 |
989 DCHECK(found) << "Pending transaction not found"; | 1148 DCHECK(found) << "Pending transaction not found"; |
990 } | 1149 } |
991 | 1150 |
992 bool HttpCache::RemovePendingTransactionFromEntry(ActiveEntry* entry, | 1151 bool HttpCache::RemovePendingTransactionFromEntry(ActiveEntry* entry, |
993 Transaction* trans) { | 1152 Transaction* transaction) { |
994 TransactionList& pending_queue = entry->pending_queue; | 1153 TransactionList& add_to_entry_queue = entry->add_to_entry_queue; |
995 | 1154 |
996 auto j = find(pending_queue.begin(), pending_queue.end(), trans); | 1155 auto j = |
997 if (j == pending_queue.end()) | 1156 find(add_to_entry_queue.begin(), add_to_entry_queue.end(), transaction); |
1157 if (j == add_to_entry_queue.end()) | |
998 return false; | 1158 return false; |
999 | 1159 |
1000 pending_queue.erase(j); | 1160 add_to_entry_queue.erase(j); |
1001 return true; | 1161 return true; |
1002 } | 1162 } |
1003 | 1163 |
1004 bool HttpCache::RemovePendingTransactionFromPendingOp(PendingOp* pending_op, | 1164 bool HttpCache::RemovePendingTransactionFromPendingOp(PendingOp* pending_op, |
1005 Transaction* trans) { | 1165 Transaction* trans) { |
1006 if (pending_op->writer->Matches(trans)) { | 1166 if (pending_op->writer->Matches(trans)) { |
1007 pending_op->writer->ClearTransaction(); | 1167 pending_op->writer->ClearTransaction(); |
1008 pending_op->writer->ClearEntry(); | 1168 pending_op->writer->ClearEntry(); |
1009 return true; | 1169 return true; |
1010 } | 1170 } |
1011 WorkItemList& pending_queue = pending_op->pending_queue; | 1171 WorkItemList& pending_queue = pending_op->pending_queue; |
1012 | 1172 |
1013 for (auto it = pending_queue.begin(); it != pending_queue.end(); ++it) { | 1173 for (auto it = pending_queue.begin(); it != pending_queue.end(); ++it) { |
1014 if ((*it)->Matches(trans)) { | 1174 if ((*it)->Matches(trans)) { |
1015 pending_queue.erase(it); | 1175 pending_queue.erase(it); |
1016 return true; | 1176 return true; |
1017 } | 1177 } |
1018 } | 1178 } |
1019 return false; | 1179 return false; |
1020 } | 1180 } |
1021 | 1181 |
1022 void HttpCache::ProcessPendingQueue(ActiveEntry* entry) { | |
1023 // Multiple readers may finish with an entry at once, so we want to batch up | |
1024 // calls to OnProcessPendingQueue. This flag also tells us that we should | |
1025 // not delete the entry before OnProcessPendingQueue runs. | |
1026 if (entry->will_process_pending_queue) | |
1027 return; | |
1028 entry->will_process_pending_queue = true; | |
1029 | |
1030 base::ThreadTaskRunnerHandle::Get()->PostTask( | |
1031 FROM_HERE, | |
1032 base::Bind(&HttpCache::OnProcessPendingQueue, GetWeakPtr(), entry)); | |
1033 } | |
1034 | |
1035 void HttpCache::OnProcessPendingQueue(ActiveEntry* entry) { | |
1036 entry->will_process_pending_queue = false; | |
1037 DCHECK(!entry->writer); | |
1038 | |
1039 // If no one is interested in this entry, then we can deactivate it. | |
1040 if (entry->HasNoTransactions()) { | |
1041 DestroyEntry(entry); | |
1042 return; | |
1043 } | |
1044 | |
1045 if (entry->pending_queue.empty()) | |
1046 return; | |
1047 | |
1048 // Promote next transaction from the pending queue. | |
1049 Transaction* next = entry->pending_queue.front(); | |
1050 if ((next->mode() & Transaction::WRITE) && !entry->readers.empty()) | |
1051 return; // Have to wait. | |
1052 | |
1053 entry->pending_queue.erase(entry->pending_queue.begin()); | |
1054 | |
1055 int rv = AddTransactionToEntry(entry, next); | |
1056 if (rv != ERR_IO_PENDING) { | |
1057 next->io_callback().Run(rv); | |
1058 } | |
1059 } | |
1060 | |
1061 void HttpCache::OnIOComplete(int result, PendingOp* pending_op) { | 1182 void HttpCache::OnIOComplete(int result, PendingOp* pending_op) { |
1062 WorkItemOperation op = pending_op->writer->operation(); | 1183 WorkItemOperation op = pending_op->writer->operation(); |
1063 | 1184 |
1064 // Completing the creation of the backend is simpler than the other cases. | 1185 // Completing the creation of the backend is simpler than the other cases. |
1065 if (op == WI_CREATE_BACKEND) | 1186 if (op == WI_CREATE_BACKEND) |
1066 return OnBackendCreated(result, pending_op); | 1187 return OnBackendCreated(result, pending_op); |
1067 | 1188 |
1068 std::unique_ptr<WorkItem> item = std::move(pending_op->writer); | 1189 std::unique_ptr<WorkItem> item = std::move(pending_op->writer); |
1069 bool fail_requests = false; | 1190 bool fail_requests = false; |
1070 | 1191 |
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1195 building_backend_ = false; | 1316 building_backend_ = false; |
1196 DeletePendingOp(pending_op); | 1317 DeletePendingOp(pending_op); |
1197 } | 1318 } |
1198 | 1319 |
1199 // The cache may be gone when we return from the callback. | 1320 // The cache may be gone when we return from the callback. |
1200 if (!item->DoCallback(result, disk_cache_.get())) | 1321 if (!item->DoCallback(result, disk_cache_.get())) |
1201 item->NotifyTransaction(result, NULL); | 1322 item->NotifyTransaction(result, NULL); |
1202 } | 1323 } |
1203 | 1324 |
1204 } // namespace net | 1325 } // namespace net |
OLD | NEW |