media/mtransport/transportflow.h@97036ab72558 (annotated)
media/mtransport/transportflow.h
Tue, 06 Jan 2015 21:39:09 +0100
- author
- Michael Schloh von Bennewitz <michael@schloh.com>
- date
- Tue, 06 Jan 2015 21:39:09 +0100
- branch
- TOR_BUG_9701
- changeset 8
- 97036ab72558
- permissions
- -rw-r--r--
Conditionally force memory storage according to privacy.thirdparty.isolate;
This solves Tor bug #9701, complying with disk avoidance documented in
https://www.torproject.org/projects/torbrowser/design/#disk-avoidance.
| michael@0 | 1 | /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ |
| michael@0 | 2 | /* vim: set ts=2 et sw=2 tw=80: */ |
| michael@0 | 3 | /* This Source Code Form is subject to the terms of the Mozilla Public |
| michael@0 | 4 | * License, v. 2.0. If a copy of the MPL was not distributed with this file, |
| michael@0 | 5 | * You can obtain one at http://mozilla.org/MPL/2.0/. */ |
| michael@0 | 6 | |
| michael@0 | 7 | // Original author: ekr@rtfm.com |
| michael@0 | 8 | |
| michael@0 | 9 | #ifndef transportflow_h__ |
| michael@0 | 10 | #define transportflow_h__ |
| michael@0 | 11 | |
| michael@0 | 12 | #include <deque> |
| michael@0 | 13 | #include <queue> |
| michael@0 | 14 | #include <string> |
| michael@0 | 15 | |
| michael@0 | 16 | #include "nscore.h" |
| michael@0 | 17 | #include "nsISupportsImpl.h" |
| michael@0 | 18 | #include "mozilla/Scoped.h" |
| michael@0 | 19 | #include "transportlayer.h" |
| michael@0 | 20 | #include "m_cpp_utils.h" |
| michael@0 | 21 | #include "nsAutoPtr.h" |
| michael@0 | 22 | |
| michael@0 | 23 | // A stack of transport layers acts as a flow. |
| michael@0 | 24 | // Generally, one reads and writes to the top layer. |
| michael@0 | 25 | |
| michael@0 | 26 | // This code has a confusing hybrid threading model which |
| michael@0 | 27 | // probably needs some eventual refactoring. |
| michael@0 | 28 | // TODO(ekr@rtfm.com): Bug 844891 |
| michael@0 | 29 | // |
| michael@0 | 30 | // TransportFlows are not inherently bound to a thread *but* |
| michael@0 | 31 | // TransportLayers can be. If any layer in a flow is bound |
| michael@0 | 32 | // to a given thread, then all layers in the flow MUST be |
| michael@0 | 33 | // bound to that thread and you can only manipulate the |
| michael@0 | 34 | // flow (push layers, write, etc.) on that thread. |
| michael@0 | 35 | // |
| michael@0 | 36 | // The sole official exception to this is that you are |
| michael@0 | 37 | // allowed to *destroy* a flow off the bound thread provided |
| michael@0 | 38 | // that there are no listeners on its signals. This exception |
| michael@0 | 39 | // is designed to allow idioms where you create the flow |
| michael@0 | 40 | // and then something goes wrong and you destroy it and |
| michael@0 | 41 | // you don't want to bother with a thread dispatch. |
| michael@0 | 42 | // |
| michael@0 | 43 | // Eventually we hope to relax the "no listeners" |
| michael@0 | 44 | // restriction by thread-locking the signals, but previous |
| michael@0 | 45 | // attempts have caused deadlocks. |
| michael@0 | 46 | // |
| michael@0 | 47 | // Most of these invariants are enforced by hard asserts |
| michael@0 | 48 | // (i.e., those which fire even in production builds). |
| michael@0 | 49 | |
| michael@0 | 50 | namespace mozilla { |
| michael@0 | 51 | |
| michael@0 | 52 | class TransportFlow : public nsISupports, |
| michael@0 | 53 | public sigslot::has_slots<> { |
| michael@0 | 54 | public: |
| michael@0 | 55 | TransportFlow() |
| michael@0 | 56 | : id_("(anonymous)"), |
| michael@0 | 57 | state_(TransportLayer::TS_NONE), |
| michael@0 | 58 | layers_(new std::deque<TransportLayer *>) {} |
| michael@0 | 59 | TransportFlow(const std::string id) |
| michael@0 | 60 | : id_(id), |
| michael@0 | 61 | state_(TransportLayer::TS_NONE), |
| michael@0 | 62 | layers_(new std::deque<TransportLayer *>) {} |
| michael@0 | 63 | |
| michael@0 | 64 | ~TransportFlow(); |
| michael@0 | 65 | |
| michael@0 | 66 | const std::string& id() const { return id_; } |
| michael@0 | 67 | |
| michael@0 | 68 | // Layer management. Note PushLayer() is not thread protected, so |
| michael@0 | 69 | // either: |
| michael@0 | 70 | // (a) Do it in the thread handling the I/O |
| michael@0 | 71 | // (b) Do it before you activate the I/O system |
| michael@0 | 72 | // |
| michael@0 | 73 | // The flow takes ownership of the layers after a successful |
| michael@0 | 74 | // push. |
| michael@0 | 75 | nsresult PushLayer(TransportLayer *layer); |
| michael@0 | 76 | |
| michael@0 | 77 | // Convenience function to push multiple layers on. Layers |
| michael@0 | 78 | // are pushed on in the order that they are in the queue. |
| michael@0 | 79 | // Any failures cause the flow to become inoperable and |
| michael@0 | 80 | // destroys all the layers including those already pushed. |
| michael@0 | 81 | // TODO(ekr@rtfm.com): Change layers to be ref-counted. |
| michael@0 | 82 | nsresult PushLayers(nsAutoPtr<std::queue<TransportLayer *> > layers); |
| michael@0 | 83 | |
| michael@0 | 84 | TransportLayer *top() const; |
| michael@0 | 85 | TransportLayer *GetLayer(const std::string& id) const; |
| michael@0 | 86 | |
| michael@0 | 87 | // Wrappers for whatever TLayer happens to be the top layer |
| michael@0 | 88 | // at the time. This way you don't need to do top()->Foo(). |
| michael@0 | 89 | TransportLayer::State state(); // Current state |
| michael@0 | 90 | TransportResult SendPacket(const unsigned char *data, size_t len); |
| michael@0 | 91 | |
| michael@0 | 92 | // State has changed. Reflects the top flow. |
| michael@0 | 93 | sigslot::signal2<TransportFlow *, TransportLayer::State> |
| michael@0 | 94 | SignalStateChange; |
| michael@0 | 95 | |
| michael@0 | 96 | // Data received on the flow |
| michael@0 | 97 | sigslot::signal3<TransportFlow*, const unsigned char *, size_t> |
| michael@0 | 98 | SignalPacketReceived; |
| michael@0 | 99 | |
| michael@0 | 100 | bool Contains(TransportLayer *layer) const; |
| michael@0 | 101 | |
| michael@0 | 102 | NS_DECL_THREADSAFE_ISUPPORTS |
| michael@0 | 103 | |
| michael@0 | 104 | private: |
| michael@0 | 105 | DISALLOW_COPY_ASSIGN(TransportFlow); |
| michael@0 | 106 | |
| michael@0 | 107 | // Check if we are on the right thread |
| michael@0 | 108 | void CheckThread() const { |
| michael@0 | 109 | if (!CheckThreadInt()) |
| michael@0 | 110 | MOZ_CRASH(); |
| michael@0 | 111 | } |
| michael@0 | 112 | |
| michael@0 | 113 | bool CheckThreadInt() const { |
| michael@0 | 114 | bool on; |
| michael@0 | 115 | |
| michael@0 | 116 | if (!target_) // OK if no thread set. |
| michael@0 | 117 | return true; |
| michael@0 | 118 | if (NS_FAILED(target_->IsOnCurrentThread(&on))) |
| michael@0 | 119 | return false; |
| michael@0 | 120 | |
| michael@0 | 121 | return on; |
| michael@0 | 122 | } |
| michael@0 | 123 | |
| michael@0 | 124 | void EnsureSameThread(TransportLayer *layer); |
| michael@0 | 125 | |
| michael@0 | 126 | void StateChange(TransportLayer *layer, TransportLayer::State state); |
| michael@0 | 127 | void StateChangeInt(TransportLayer::State state); |
| michael@0 | 128 | void PacketReceived(TransportLayer* layer, const unsigned char *data, |
| michael@0 | 129 | size_t len); |
| michael@0 | 130 | static void DestroyFinal(nsAutoPtr<std::deque<TransportLayer *> > layers); |
| michael@0 | 131 | |
| michael@0 | 132 | // Overload needed because we use deque internally and queue externally. |
| michael@0 | 133 | static void ClearLayers(std::deque<TransportLayer *>* layers); |
| michael@0 | 134 | static void ClearLayers(std::queue<TransportLayer *>* layers); |
| michael@0 | 135 | |
| michael@0 | 136 | std::string id_; |
| michael@0 | 137 | TransportLayer::State state_; |
| michael@0 | 138 | ScopedDeletePtr<std::deque<TransportLayer *> > layers_; |
| michael@0 | 139 | nsCOMPtr<nsIEventTarget> target_; |
| michael@0 | 140 | }; |
| michael@0 | 141 | |
| michael@0 | 142 | } // close namespace |
| michael@0 | 143 | #endif |
