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// Copyright 2013 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.
#include "mojo/system/local_message_pipe_endpoint.h"
#include <string.h>
#include "base/logging.h"
#include "mojo/system/dispatcher.h"
#include "mojo/system/message_in_transit.h"
namespace mojo {
namespace system {
LocalMessagePipeEndpoint::LocalMessagePipeEndpoint()
: is_open_(true),
is_peer_open_(true) {
}
LocalMessagePipeEndpoint::~LocalMessagePipeEndpoint() {
DCHECK(!is_open_);
DCHECK(message_queue_.IsEmpty()); // Should be implied by not being open.
}
MessagePipeEndpoint::Type LocalMessagePipeEndpoint::GetType() const {
return kTypeLocal;
}
bool LocalMessagePipeEndpoint::OnPeerClose() {
DCHECK(is_open_);
DCHECK(is_peer_open_);
MojoWaitFlags old_satisfied_flags = SatisfiedFlags();
MojoWaitFlags old_satisfiable_flags = SatisfiableFlags();
is_peer_open_ = false;
MojoWaitFlags new_satisfied_flags = SatisfiedFlags();
MojoWaitFlags new_satisfiable_flags = SatisfiableFlags();
if (new_satisfied_flags != old_satisfied_flags ||
new_satisfiable_flags != old_satisfiable_flags) {
waiter_list_.AwakeWaitersForStateChange(new_satisfied_flags,
new_satisfiable_flags);
}
return true;
}
void LocalMessagePipeEndpoint::EnqueueMessage(
scoped_ptr<MessageInTransit> message) {
DCHECK(is_open_);
DCHECK(is_peer_open_);
bool was_empty = message_queue_.IsEmpty();
message_queue_.AddMessage(message.Pass());
if (was_empty) {
waiter_list_.AwakeWaitersForStateChange(SatisfiedFlags(),
SatisfiableFlags());
}
}
void LocalMessagePipeEndpoint::Close() {
DCHECK(is_open_);
is_open_ = false;
message_queue_.Clear();
}
void LocalMessagePipeEndpoint::CancelAllWaiters() {
DCHECK(is_open_);
waiter_list_.CancelAllWaiters();
}
MojoResult LocalMessagePipeEndpoint::ReadMessage(void* bytes,
uint32_t* num_bytes,
DispatcherVector* dispatchers,
uint32_t* num_dispatchers,
MojoReadMessageFlags flags) {
DCHECK(is_open_);
DCHECK(!dispatchers || dispatchers->empty());
const uint32_t max_bytes = num_bytes ? *num_bytes : 0;
const uint32_t max_num_dispatchers = num_dispatchers ? *num_dispatchers : 0;
if (message_queue_.IsEmpty()) {
return is_peer_open_ ? MOJO_RESULT_SHOULD_WAIT :
MOJO_RESULT_FAILED_PRECONDITION;
}
// TODO(vtl): If |flags & MOJO_READ_MESSAGE_FLAG_MAY_DISCARD|, we could pop
// and release the lock immediately.
bool enough_space = true;
MessageInTransit* message = message_queue_.PeekMessage();
if (num_bytes)
*num_bytes = message->num_bytes();
if (message->num_bytes() <= max_bytes)
memcpy(bytes, message->bytes(), message->num_bytes());
else
enough_space = false;
if (DispatcherVector* queued_dispatchers = message->dispatchers()) {
if (num_dispatchers)
*num_dispatchers = static_cast<uint32_t>(queued_dispatchers->size());
if (enough_space) {
if (queued_dispatchers->empty()) {
// Nothing to do.
} else if (queued_dispatchers->size() <= max_num_dispatchers) {
DCHECK(dispatchers);
dispatchers->swap(*queued_dispatchers);
} else {
enough_space = false;
}
}
} else {
if (num_dispatchers)
*num_dispatchers = 0;
}
message = NULL;
if (enough_space || (flags & MOJO_READ_MESSAGE_FLAG_MAY_DISCARD)) {
message_queue_.DiscardMessage();
// Now it's empty, thus no longer readable.
if (message_queue_.IsEmpty()) {
// It's currently not possible to wait for non-readability, but we should
// do the state change anyway.
waiter_list_.AwakeWaitersForStateChange(SatisfiedFlags(),
SatisfiableFlags());
}
}
if (!enough_space)
return MOJO_RESULT_RESOURCE_EXHAUSTED;
return MOJO_RESULT_OK;
}
MojoResult LocalMessagePipeEndpoint::AddWaiter(Waiter* waiter,
MojoWaitFlags flags,
MojoResult wake_result) {
DCHECK(is_open_);
if ((flags & SatisfiedFlags()))
return MOJO_RESULT_ALREADY_EXISTS;
if (!(flags & SatisfiableFlags()))
return MOJO_RESULT_FAILED_PRECONDITION;
waiter_list_.AddWaiter(waiter, flags, wake_result);
return MOJO_RESULT_OK;
}
void LocalMessagePipeEndpoint::RemoveWaiter(Waiter* waiter) {
DCHECK(is_open_);
waiter_list_.RemoveWaiter(waiter);
}
MojoWaitFlags LocalMessagePipeEndpoint::SatisfiedFlags() {
MojoWaitFlags satisfied_flags = 0;
if (!message_queue_.IsEmpty())
satisfied_flags |= MOJO_WAIT_FLAG_READABLE;
if (is_peer_open_)
satisfied_flags |= MOJO_WAIT_FLAG_WRITABLE;
return satisfied_flags;
}
MojoWaitFlags LocalMessagePipeEndpoint::SatisfiableFlags() {
MojoWaitFlags satisfiable_flags = 0;
if (!message_queue_.IsEmpty() || is_peer_open_)
satisfiable_flags |= MOJO_WAIT_FLAG_READABLE;
if (is_peer_open_)
satisfiable_flags |= MOJO_WAIT_FLAG_WRITABLE;
return satisfiable_flags;
}
} // namespace system
} // namespace mojo
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