| Index: mojo/edk/system/channel_endpoint.h
|
| diff --git a/mojo/edk/system/channel_endpoint.h b/mojo/edk/system/channel_endpoint.h
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| deleted file mode 100644
|
| index 90ee86b758399f912c93baac0d54b643e4d39036..0000000000000000000000000000000000000000
|
| --- a/mojo/edk/system/channel_endpoint.h
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| +++ /dev/null
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| @@ -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
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| -// 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.
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| -// - When a message pipe endpoint is detached from a channel, it is also
|
| -// taken out of the running state. After that point, messages should
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| -// 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
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| -// 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
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| -// 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).
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| -// - 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
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| -// under |lock_|.) [TODO(vtl): When I add remotely-allocated IDs,
|
| -// we'll have to remove the |EndpointInfo| from
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| -// |local_id_to_endpoint_info_map_| -- i.e., remove the local ID,
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| -// since it's no longer valid and may be reused by the remote side --
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| -// 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
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| -// will detach the endpoint, and send a "remove" control message.
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| -// However, the channel may still receive messages for that endpoint
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| -// until it receives a "remove ack" control message.
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| -// - If the local side is closed but the message pipe endpoint was not
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| -// yet running , the detaching is delayed until after it is run and
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| -// 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.
|
| - //
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| - // 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_
|
|
|