channel: Simplify resource management

- Remove unused rpc_call_level field
- Add `returned` field to ChannelCallFrame. This is set when the call returns
  and is the only condition checked by `channel_send_call`.
- Add job_exit callback for properly closing channels created from job(the
  job_exit callback is only called after all read callbacks, so it's the only
  safe place to free the channel).
This commit is contained in:
Thiago de Arruda
2014-10-20 07:46:19 -03:00
parent b280308ac6
commit cf6f60ce4d

View File

@@ -31,14 +31,14 @@
typedef struct {
uint64_t request_id;
bool errored;
bool returned, errored;
Object result;
} ChannelCallFrame;
typedef struct {
uint64_t id;
PMap(cstr_t) *subscribed_events;
bool is_job, enabled;
bool is_job, closed;
msgpack_unpacker *unpacker;
union {
Job *job;
@@ -50,7 +50,6 @@ typedef struct {
} data;
uint64_t next_request_id;
kvec_t(ChannelCallFrame *) call_stack;
size_t rpc_call_level;
} Channel;
static uint64_t next_id = 1;
@@ -103,12 +102,12 @@ uint64_t channel_from_job(char **argv)
channel,
job_out,
job_err,
NULL,
job_exit,
0,
&status);
if (status <= 0) {
close_channel(channel);
free_channel(channel);
return 0;
}
@@ -141,7 +140,7 @@ bool channel_exists(uint64_t id)
{
Channel *channel;
return (channel = pmap_get(uint64_t)(channels, id)) != NULL
&& channel->enabled;
&& !channel->closed;
}
/// Sends event/arguments to channel
@@ -156,7 +155,7 @@ bool channel_send_event(uint64_t id, char *name, Array args)
Channel *channel = NULL;
if (id > 0) {
if (!(channel = pmap_get(uint64_t)(channels, id)) || !channel->enabled) {
if (!(channel = pmap_get(uint64_t)(channels, id)) || channel->closed) {
api_free_array(args);
return false;
}
@@ -182,7 +181,7 @@ Object channel_send_call(uint64_t id,
{
Channel *channel = NULL;
if (!(channel = pmap_get(uint64_t)(channels, id)) || !channel->enabled) {
if (!(channel = pmap_get(uint64_t)(channels, id)) || channel->closed) {
api_set_error(err, Exception, _("Invalid channel \"%" PRIu64 "\""), id);
api_free_array(args);
return NIL;
@@ -208,16 +207,14 @@ Object channel_send_call(uint64_t id,
EventSource sources[] = {channel_source, NULL};
// Push the frame
ChannelCallFrame frame = {request_id, false, NIL};
ChannelCallFrame frame = {request_id, false, false, NIL};
kv_push(ChannelCallFrame *, channel->call_stack, &frame);
size_t size = kv_size(channel->call_stack);
do {
event_poll(-1, sources);
} while (
// Continue running if ...
channel->enabled && // the channel is still enabled
kv_size(channel->call_stack) >= size); // the call didn't return
} while (!frame.returned);
(void)kv_pop(channel->call_stack);
if (frame.errored) {
api_set_error(err, Exception, "%s", frame.result.data.string.data);
@@ -235,7 +232,7 @@ void channel_subscribe(uint64_t id, char *event)
{
Channel *channel;
if (!(channel = pmap_get(uint64_t)(channels, id)) || !channel->enabled) {
if (!(channel = pmap_get(uint64_t)(channels, id)) || channel->closed) {
abort();
}
@@ -257,7 +254,7 @@ void channel_unsubscribe(uint64_t id, char *event)
{
Channel *channel;
if (!(channel = pmap_get(uint64_t)(channels, id)) || !channel->enabled) {
if (!(channel = pmap_get(uint64_t)(channels, id)) || channel->closed) {
abort();
}
@@ -272,12 +269,11 @@ bool channel_close(uint64_t id)
{
Channel *channel;
if (!(channel = pmap_get(uint64_t)(channels, id)) || !channel->enabled) {
if (!(channel = pmap_get(uint64_t)(channels, id)) || channel->closed) {
return false;
}
channel_kill(channel);
channel->enabled = false;
close_channel(channel);
return true;
}
@@ -319,19 +315,16 @@ static void job_err(RStream *rstream, void *data, bool eof)
}
}
static void job_exit(Job *job, void *data)
{
free_channel((Channel *)data);
}
static void parse_msgpack(RStream *rstream, void *data, bool eof)
{
Channel *channel = data;
channel->rpc_call_level++;
if (eof) {
char buf[256];
snprintf(buf,
sizeof(buf),
"Before returning from a RPC call, channel %" PRIu64 " was "
"closed by the client",
channel->id);
call_set_error(channel, buf);
goto end;
}
@@ -354,7 +347,7 @@ static void parse_msgpack(RStream *rstream, void *data, bool eof)
MSGPACK_UNPACK_SUCCESS) {
if (kv_size(channel->call_stack) && is_rpc_response(&unpacked.data)) {
if (is_valid_rpc_response(&unpacked.data, channel)) {
call_stack_pop(&unpacked.data, channel);
complete_call(&unpacked.data, channel);
} else {
char buf[256];
snprintf(buf,
@@ -397,10 +390,11 @@ static void parse_msgpack(RStream *rstream, void *data, bool eof)
}
end:
channel->rpc_call_level--;
if (!channel->enabled && !kv_size(channel->call_stack)) {
// Now it's safe to destroy the channel
close_channel(channel);
if (eof && !channel->is_job && !kv_size(channel->call_stack)) {
// The free_channel call is deferred for jobs because it's possible that
// job_stderr will called after this. For non-job channels, this is the
// last callback so it must be freed now.
free_channel(channel);
}
}
@@ -500,26 +494,11 @@ static void unsubscribe(Channel *channel, char *event)
free(event_string);
}
/// Close the channel streams/job. The channel resources will be freed by
/// free_channel later.
static void close_channel(Channel *channel)
{
pmap_del(uint64_t)(channels, channel->id);
msgpack_unpacker_free(channel->unpacker);
// Unsubscribe from all events
char *event_string;
map_foreach_value(channel->subscribed_events, event_string, {
unsubscribe(channel, event_string);
});
pmap_free(cstr_t)(channel->subscribed_events);
kv_destroy(channel->call_stack);
channel_kill(channel);
free(channel);
}
static void channel_kill(Channel *channel)
{
channel->closed = true;
if (channel->is_job) {
if (channel->data.job) {
job_stop(channel->data.job);
@@ -536,6 +515,22 @@ static void channel_kill(Channel *channel)
}
}
static void free_channel(Channel *channel)
{
pmap_del(uint64_t)(channels, channel->id);
msgpack_unpacker_free(channel->unpacker);
// Unsubscribe from all events
char *event_string;
map_foreach_value(channel->subscribed_events, event_string, {
unsubscribe(channel, event_string);
});
pmap_free(cstr_t)(channel->subscribed_events);
kv_destroy(channel->call_stack);
free(channel);
}
static void close_cb(uv_handle_t *handle)
{
free(handle->data);
@@ -545,8 +540,7 @@ static void close_cb(uv_handle_t *handle)
static Channel *register_channel(void)
{
Channel *rv = xmalloc(sizeof(Channel));
rv->enabled = true;
rv->rpc_call_level = 0;
rv->closed = false;
rv->unpacker = msgpack_unpacker_new(MSGPACK_UNPACKER_INIT_BUFFER_SIZE);
rv->id = next_id++;
rv->subscribed_events = pmap_new(cstr_t)();
@@ -573,9 +567,11 @@ static bool is_valid_rpc_response(msgpack_object *obj, Channel *channel)
kv_size(channel->call_stack) - 1)->request_id;
}
static void call_stack_pop(msgpack_object *obj, Channel *channel)
static void complete_call(msgpack_object *obj, Channel *channel)
{
ChannelCallFrame *frame = kv_pop(channel->call_stack);
ChannelCallFrame *frame = kv_A(channel->call_stack,
kv_size(channel->call_stack) - 1);
frame->returned = true;
frame->errored = obj->via.array.ptr[2].type != MSGPACK_OBJECT_NIL;
if (frame->errored) {
@@ -588,10 +584,11 @@ static void call_stack_pop(msgpack_object *obj, Channel *channel)
static void call_set_error(Channel *channel, char *msg)
{
for (size_t i = 0; i < kv_size(channel->call_stack); i++) {
ChannelCallFrame *frame = kv_pop(channel->call_stack);
ChannelCallFrame *frame = kv_A(channel->call_stack, i);
frame->returned = true;
frame->errored = true;
frame->result = STRING_OBJ(cstr_to_string(msg));
}
channel->enabled = false;
close_channel(channel);
}