Index: mojo/edk/system/channel_endpoint.h |
diff --git a/mojo/edk/system/channel_endpoint.h b/mojo/edk/system/channel_endpoint.h |
deleted file mode 100644 |
index 90ee86b758399f912c93baac0d54b643e4d39036..0000000000000000000000000000000000000000 |
--- a/mojo/edk/system/channel_endpoint.h |
+++ /dev/null |
@@ -1,210 +0,0 @@ |
-// Copyright 2014 The Chromium Authors. All rights reserved. |
-// Use of this source code is governed by a BSD-style license that can be |
-// found in the LICENSE file. |
- |
-#ifndef MOJO_EDK_SYSTEM_CHANNEL_ENDPOINT_H_ |
-#define MOJO_EDK_SYSTEM_CHANNEL_ENDPOINT_H_ |
- |
-#include "base/macros.h" |
-#include "base/memory/ref_counted.h" |
-#include "base/memory/scoped_ptr.h" |
-#include "base/synchronization/lock.h" |
-#include "mojo/edk/system/channel_endpoint_id.h" |
-#include "mojo/edk/system/message_in_transit_queue.h" |
-#include "mojo/edk/system/system_impl_export.h" |
- |
-namespace mojo { |
-namespace system { |
- |
-class Channel; |
-class ChannelEndpointClient; |
-class MessageInTransit; |
- |
-// TODO(vtl): The plan: |
-// - (Done.) Move |Channel::Endpoint| to |ChannelEndpoint|. Make it |
-// refcounted, and not copyable. Make |Channel| a friend. Make things work. |
-// - (Done.) Give |ChannelEndpoint| a lock. The lock order (in order of |
-// allowable acquisition) is: |MessagePipe|, |ChannelEndpoint|, |Channel|. |
-// - (Done) Stop having |Channel| as a friend. |
-// - (Done) Move logic from |ProxyMessagePipeEndpoint| into |ChannelEndpoint|. |
-// Right now, we have to go through lots of contortions to manipulate state |
-// owned by |ProxyMessagePipeEndpoint| (in particular, |Channel::Endpoint| |
-// doesn't know about the remote ID; the local ID is duplicated in two |
-// places). Hollow out |ProxyMessagePipeEndpoint|, and have it just own a |
-// reference to |ChannelEndpoint| (hence the refcounting). |
-// - In essence, |ChannelEndpoint| becomes the thing that knows about |
-// channel-specific aspects of an endpoint (notably local and remote IDs, |
-// and knowledge about handshaking), and mediates between the |Channel| and |
-// the |MessagePipe|. |
-// - In the end state, |Channel| should no longer need to know about |
-// |MessagePipe| and ports (but only |ChannelEndpoint|) and |
-// |ProxyMessagePipeEndpoint| should no longer need to know about |Channel| |
-// (ditto). |
-// |
-// Things as they are now, before I change everything (TODO(vtl): update this |
-// comment appropriately): |
-// |
-// Terminology: |
-// - "Message pipe endpoint": In the implementation, a |MessagePipe| owns |
-// two |MessagePipeEndpoint| objects, one for each port. The |
-// |MessagePipeEndpoint| objects are only accessed via the |MessagePipe| |
-// (which has the lock), with the additional information of the port |
-// number. So as far as the channel is concerned, a message pipe endpoint |
-// is a pointer to a |MessagePipe| together with the port number. |
-// - The value of |port| in |EndpointInfo| refers to the |
-// |ProxyMessagePipeEndpoint| (i.e., the endpoint that is logically on |
-// the other side). Messages received by a channel for a message pipe |
-// are thus written to the *peer* of this port. |
-// - "Attached"/"detached": A message pipe endpoint is attached to a channel |
-// if it has a pointer to it. It must be detached before the channel gives |
-// up its pointer to it in order to break a reference cycle. (This cycle |
-// is needed to allow a channel to be shut down cleanly, without shutting |
-// down everything else first.) |
-// - "Running" (message pipe endpoint): A message pipe endpoint is running |
-// if messages written to it (via some |MessagePipeDispatcher|, to which |
-// some |MojoHandle| is assigned) are being transmitted through the |
-// channel. |
-// - Before a message pipe endpoint is run, it will queue messages. |
-// - When a message pipe endpoint is detached from a channel, it is also |
-// taken out of the running state. After that point, messages should |
-// no longer be written to it. |
-// - "Normal" message pipe endpoint (state): The channel itself does not |
-// have knowledge of whether a message pipe endpoint has started running |
-// yet. It will *receive* messages for a message pipe in either state (but |
-// the message pipe endpoint won't *send* messages to the channel if it |
-// has not started running). |
-// - "Zombie" message pipe endpoint (state): A message pipe endpoint is a |
-// zombie if it is still in |local_id_to_endpoint_info_map_|, but the |
-// channel is no longer forwarding messages to it (even if it may still be |
-// receiving messages for it). |
-// - There are various types of zombies, depending on the reason the |
-// message pipe endpoint cannot yet be removed. |
-// - If the remote side is closed, it will send a "remove" control |
-// message. After the channel receives that message (to which it |
-// responds with a "remove ack" control message), it knows that it |
-// shouldn't receive any more messages for that message pipe endpoint |
-// (local ID), but it must wait for the endpoint to detach. (It can't |
-// do so without a race, since it can't call into the message pipe |
-// under |lock_|.) [TODO(vtl): When I add remotely-allocated IDs, |
-// we'll have to remove the |EndpointInfo| from |
-// |local_id_to_endpoint_info_map_| -- i.e., remove the local ID, |
-// since it's no longer valid and may be reused by the remote side -- |
-// and keep the |EndpointInfo| alive in some other way.] |
-// - If the local side is closed and the message pipe endpoint was |
-// already running (so there are no queued messages left to send), it |
-// will detach the endpoint, and send a "remove" control message. |
-// However, the channel may still receive messages for that endpoint |
-// until it receives a "remove ack" control message. |
-// - If the local side is closed but the message pipe endpoint was not |
-// yet running , the detaching is delayed until after it is run and |
-// all the queued messages are sent to the channel. On being detached, |
-// things proceed as in one of the above cases. The endpoint is *not* |
-// a zombie until it is detached (or a "remove" message is received). |
-// [TODO(vtl): Maybe we can get rid of this case? It'd only not yet be |
-// running since under the current scheme it wouldn't have a remote ID |
-// yet.] |
-// - Note that even if the local side is closed, it may still receive a |
-// "remove" message from the other side (if the other side is closed |
-// simultaneously, and both sides send "remove" messages). In that |
-// case, it must still remain alive until it receives the "remove |
-// ack" (and it must ack the "remove" message that it received). |
-class MOJO_SYSTEM_IMPL_EXPORT ChannelEndpoint |
- : public base::RefCountedThreadSafe<ChannelEndpoint> { |
- public: |
- // Constructor for a |ChannelEndpoint| with the given client (specified by |
- // |client| and |client_port|). Optionally takes messages from |
- // |*message_queue| if |message_queue| is non-null. |
- // |
- // |client| may be null if this endpoint will never need to receive messages, |
- // in which case |message_queue| should not be null. In that case, this |
- // endpoint will simply send queued messages upon being attached to a |
- // |Channel| and immediately detach itself. |
- ChannelEndpoint(ChannelEndpointClient* client, |
- unsigned client_port, |
- MessageInTransitQueue* message_queue = nullptr); |
- |
- // Methods called by |ChannelEndpointClient|: |
- |
- // Called to enqueue an outbound message. (If |AttachAndRun()| has not yet |
- // been called, the message will be enqueued and sent when |AttachAndRun()| is |
- // called.) |
- bool EnqueueMessage(scoped_ptr<MessageInTransit> message); |
- |
- // Called to *replace* current client with a new client (which must differ |
- // from the existing client). This must not be called after |
- // |DetachFromClient()| has been called. |
- // |
- // This returns true in the typical case, and false if this endpoint has been |
- // detached from the channel, in which case the caller should probably call |
- // its (new) client's |OnDetachFromChannel()|. |
- bool ReplaceClient(ChannelEndpointClient* client, unsigned client_port); |
- |
- // Called before the |ChannelEndpointClient| gives up its reference to this |
- // object. |
- void DetachFromClient(); |
- |
- // Methods called by |Channel|: |
- |
- // Called when the |Channel| takes a reference to this object. This will send |
- // all queue messages (in |channel_message_queue_|). |
- // TODO(vtl): Maybe rename this "OnAttach"? |
- void AttachAndRun(Channel* channel, |
- ChannelEndpointId local_id, |
- ChannelEndpointId remote_id); |
- |
- // Called when the |Channel| receives a message for the |ChannelEndpoint|. |
- void OnReadMessage(scoped_ptr<MessageInTransit> message); |
- |
- // Called before the |Channel| gives up its reference to this object. |
- void DetachFromChannel(); |
- |
- private: |
- friend class base::RefCountedThreadSafe<ChannelEndpoint>; |
- ~ChannelEndpoint(); |
- |
- // Must be called with |lock_| held. |
- bool WriteMessageNoLock(scoped_ptr<MessageInTransit> message); |
- |
- // Resets |channel_| to null (and sets |is_detached_from_channel_|). This may |
- // only be called if |channel_| is non-null. Must be called with |lock_| held. |
- void ResetChannelNoLock(); |
- |
- // Protects the members below. |
- base::Lock lock_; |
- |
- // |client_| must be valid whenever it is non-null. Before |*client_| gives up |
- // its reference to this object, it must call |DetachFromClient()|. |
- // NOTE: This is a |scoped_refptr<>|, rather than a raw pointer, since the |
- // |Channel| needs to keep the |MessagePipe| alive for the "proxy-proxy" case. |
- // Possibly we'll be able to eliminate that case when we have full |
- // multiprocess support. |
- // WARNING: |ChannelEndpointClient| methods must not be called under |lock_|. |
- // Thus to make such a call, a reference must first be taken under |lock_| and |
- // the lock released. |
- // WARNING: Beware of interactions with |ReplaceClient()|. By the time the |
- // call is made, the client may have changed. This must be detected and dealt |
- // with. |
- scoped_refptr<ChannelEndpointClient> client_; |
- unsigned client_port_; |
- |
- // |channel_| must be valid whenever it is non-null. Before |*channel_| gives |
- // up its reference to this object, it must call |DetachFromChannel()|. |
- // |local_id_| and |remote_id_| are valid if and only |channel_| is non-null. |
- Channel* channel_; |
- ChannelEndpointId local_id_; |
- ChannelEndpointId remote_id_; |
- // This distinguishes the two cases of |channel| being null: not yet attached |
- // versus detached. |
- bool is_detached_from_channel_; |
- |
- // This queue is used before we're running on a channel and ready to send |
- // messages to the channel. |
- MessageInTransitQueue channel_message_queue_; |
- |
- DISALLOW_COPY_AND_ASSIGN(ChannelEndpoint); |
-}; |
- |
-} // namespace system |
-} // namespace mojo |
- |
-#endif // MOJO_EDK_SYSTEM_CHANNEL_ENDPOINT_H_ |