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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/edk/system/local_message_pipe_endpoint.h"
#include <string.h>
#include "base/logging.h"
#include "mojo/edk/system/dispatcher.h"
#include "mojo/edk/system/message_in_transit.h"
namespace mojo {
namespace system {
LocalMessagePipeEndpoint::LocalMessagePipeEndpoint(
MessageInTransitQueue* message_queue)
: is_open_(true), is_peer_open_(true) {
if (message_queue)
message_queue_.Swap(message_queue);
}
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_);
HandleSignalsState old_state = GetHandleSignalsState();
is_peer_open_ = false;
HandleSignalsState new_state = GetHandleSignalsState();
if (!new_state.equals(old_state))
awakable_list_.AwakeForStateChange(new_state);
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)
awakable_list_.AwakeForStateChange(GetHandleSignalsState());
}
void LocalMessagePipeEndpoint::Close() {
DCHECK(is_open_);
is_open_ = false;
message_queue_.Clear();
}
void LocalMessagePipeEndpoint::CancelAllAwakables() {
DCHECK(is_open_);
awakable_list_.CancelAll();
}
MojoResult LocalMessagePipeEndpoint::ReadMessage(
UserPointer<void> bytes,
UserPointer<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.IsNull() ? 0 : num_bytes.Get();
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.IsNull())
num_bytes.Put(message->num_bytes());
if (message->num_bytes() <= max_bytes)
bytes.PutArray(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 = nullptr;
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.
awakable_list_.AwakeForStateChange(GetHandleSignalsState());
}
}
if (!enough_space)
return MOJO_RESULT_RESOURCE_EXHAUSTED;
return MOJO_RESULT_OK;
}
HandleSignalsState LocalMessagePipeEndpoint::GetHandleSignalsState() const {
HandleSignalsState rv;
if (!message_queue_.IsEmpty()) {
rv.satisfied_signals |= MOJO_HANDLE_SIGNAL_READABLE;
rv.satisfiable_signals |= MOJO_HANDLE_SIGNAL_READABLE;
}
if (is_peer_open_) {
rv.satisfied_signals |= MOJO_HANDLE_SIGNAL_WRITABLE;
rv.satisfiable_signals |=
MOJO_HANDLE_SIGNAL_READABLE | MOJO_HANDLE_SIGNAL_WRITABLE;
} else {
rv.satisfied_signals |= MOJO_HANDLE_SIGNAL_PEER_CLOSED;
}
rv.satisfiable_signals |= MOJO_HANDLE_SIGNAL_PEER_CLOSED;
return rv;
}
MojoResult LocalMessagePipeEndpoint::AddAwakable(
Awakable* awakable,
MojoHandleSignals signals,
uint32_t context,
HandleSignalsState* signals_state) {
DCHECK(is_open_);
HandleSignalsState state = GetHandleSignalsState();
if (state.satisfies(signals)) {
if (signals_state)
*signals_state = state;
return MOJO_RESULT_ALREADY_EXISTS;
}
if (!state.can_satisfy(signals)) {
if (signals_state)
*signals_state = state;
return MOJO_RESULT_FAILED_PRECONDITION;
}
awakable_list_.Add(awakable, signals, context);
return MOJO_RESULT_OK;
}
void LocalMessagePipeEndpoint::RemoveAwakable(
Awakable* awakable,
HandleSignalsState* signals_state) {
DCHECK(is_open_);
awakable_list_.Remove(awakable);
if (signals_state)
*signals_state = GetHandleSignalsState();
}
} // namespace system
} // namespace mojo
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