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#include <string.h>
#ifndef _WIN32
#define MM_API __attribute__((visibility ("default")))
#else
#define MM_API __attribute__((dllexport))
#endif
#define BACKEND_NAME "core/be"
#include "midimonster.h"
#include "backend.h"
static struct {
size_t n;
backend* backends;
instance*** instances;
} registry = {
.n = 0
};
//the global channel store was converted from a naive list to a hashmap of lists for performance reasons
static struct {
//channelstore hash is set up for 256 buckets
size_t n[256];
channel** entry[256];
} channels = {
.n = {
0
}
};
static size_t channelstore_hash(instance* inst, uint64_t ident){
uint64_t repr = ((uint64_t) inst) ^ ident;
return (repr ^ (repr >> 8) ^ (repr >> 16) ^ (repr >> 24) ^ (repr >> 32)) & 0xFF;
}
int backends_handle(size_t nfds, managed_fd* fds){
size_t u, p, n;
int rv = 0;
managed_fd xchg;
for(u = 0; u < registry.n && !rv; u++){
n = 0;
for(p = 0; p < nfds; p++){
if(fds[p].backend == registry.backends + u){
xchg = fds[n];
fds[n] = fds[p];
fds[p] = xchg;
n++;
}
}
//handle if there is data ready or the backend has active instances for polling
if(n || registry.instances[u]){
DBGPF("Notifying backend %s of %" PRIsize_t " waiting FDs", registry.backends[u].name, n);
rv |= registry.backends[u].process(n, fds);
if(rv){
LOGPF("Backend %s failed to handle input", registry.backends[u].name);
}
}
}
return rv;
}
int backends_notify(size_t nev, channel** c, channel_value* v){
size_t u, p, n;
int rv = 0;
channel_value xval;
channel* xchnl = NULL;
for(u = 0; u < nev && !rv; u = n){
//sort for this instance
n = u + 1;
for(p = u + 1; p < nev; p++){
if(c[p]->instance == c[u]->instance){
xval = v[p];
xchnl = c[p];
v[p] = v[n];
c[p] = c[n];
v[n] = xval;
c[n] = xchnl;
n++;
}
}
//TODO eliminate duplicates
DBGPF("Calling handler for instance %s with %" PRIsize_t " events", c[u]->instance->name, n - u);
rv |= c[u]->instance->backend->handle(c[u]->instance, n - u, c + u, v + u);
}
return 0;
}
MM_API channel* mm_channel(instance* inst, uint64_t ident, uint8_t create){
size_t u, bucket = channelstore_hash(inst, ident);
DBGPF("\tSearching for inst %" PRIu64 " ident %" PRIu64, (uint64_t) inst, ident);
for(u = 0; u < channels.n[bucket]; u++){
DBGPF("\tBucket %" PRIsize_t " entry %" PRIsize_t " inst %" PRIu64 " ident %" PRIu64, bucket, u, (uint64_t) channels.entry[bucket][u]->instance, channels.entry[bucket][u]->ident);
if(channels.entry[bucket][u]->instance == inst
&& channels.entry[bucket][u]->ident == ident){
DBGPF("Requested channel %" PRIu64 " on instance %s already exists, reusing (bucket %" PRIsize_t ", %" PRIsize_t " search steps)", ident, inst->name, bucket, u);
return channels.entry[bucket][u];
}
}
if(!create){
DBGPF("Requested unknown channel %" PRIu64 " (bucket %" PRIsize_t ") on instance %s", ident, bucket, inst->name);
return NULL;
}
DBGPF("Creating previously unknown channel %" PRIu64 " on instance %s, bucket %" PRIsize_t, ident, inst->name, bucket);
channels.entry[bucket] = realloc(channels.entry[bucket], (channels.n[bucket] + 1) * sizeof(channel*));
if(!channels.entry[bucket]){
LOG("Failed to allocate memory");
channels.n[bucket] = 0;
return NULL;
}
channels.entry[bucket][channels.n[bucket]] = calloc(1, sizeof(channel));
if(!channels.entry[bucket][channels.n[bucket]]){
LOG("Failed to allocate memory");
return NULL;
}
channels.entry[bucket][channels.n[bucket]]->instance = inst;
channels.entry[bucket][channels.n[bucket]]->ident = ident;
return channels.entry[bucket][(channels.n[bucket]++)];
}
MM_API void mm_channel_update(channel* chan, uint64_t ident){
size_t bucket = channelstore_hash(chan->instance, chan->ident), new_bucket = channelstore_hash(chan->instance, ident);
size_t u;
DBGPF("Updating identifier for inst %" PRIu64 " ident %" PRIu64 " (bucket %" PRIsize_t " to %" PRIsize_t ") to %" PRIu64, (uint64_t) chan->instance, chan->ident, bucket, new_bucket, ident);
if(bucket == new_bucket){
chan->ident = ident;
return;
}
for(u = 0; u < channels.n[bucket]; u++){
if(channels.entry[bucket][u]->instance == chan->instance
&& channels.entry[bucket][u]->ident == chan->ident){
break;
}
}
if(u == channels.n[bucket]){
DBGPF("Failed to find channel to update in bucket %" PRIsize_t, bucket);
return;
}
DBGPF("Removing channel from slot %" PRIsize_t " of %" PRIsize_t " of bucket %" PRIsize_t, u, channels.n[bucket], bucket);
//remove channel from old bucket
for(; u < channels.n[bucket] - 1; u++){
channels.entry[bucket][u] = channels.entry[bucket][u + 1];
}
//add to new bucket
channels.entry[new_bucket] = realloc(channels.entry[new_bucket], (channels.n[new_bucket] + 1) * sizeof(channel*));
if(!channels.entry[new_bucket]){
LOG("Failed to allocate memory");
channels.n[new_bucket] = 0;
return;
}
channels.entry[new_bucket][channels.n[new_bucket]] = chan;
chan->ident = ident;
channels.n[bucket]--;
channels.n[new_bucket]++;
}
instance* mm_instance(backend* b){
size_t u = 0, n = 0;
for(u = 0; u < registry.n; u++){
if(registry.backends + u == b){
//count existing instances
for(n = 0; registry.instances[u] && registry.instances[u][n]; n++){
}
//extend
registry.instances[u] = realloc(registry.instances[u], (n + 2) * sizeof(instance*));
if(!registry.instances[u]){
LOG("Failed to allocate memory");
return NULL;
}
//sentinel
registry.instances[u][n + 1] = NULL;
registry.instances[u][n] = calloc(1, sizeof(instance));
if(!registry.instances[u][n]){
LOG("Failed to allocate memory");
}
registry.instances[u][n]->backend = b;
return registry.instances[u][n];
}
}
//this should never happen
return NULL;
}
MM_API instance* mm_instance_find(char* name, uint64_t ident){
size_t b = 0;
instance** iter = NULL;
for(b = 0; b < registry.n; b++){
if(!strcmp(registry.backends[b].name, name)){
for(iter = registry.instances[b]; iter && *iter; iter++){
if((*iter)->ident == ident){
return *iter;
}
}
}
}
return NULL;
}
MM_API int mm_backend_instances(char* name, size_t* ninst, instance*** inst){
size_t b = 0, i = 0;
if(!ninst || !inst){
return 1;
}
for(b = 0; b < registry.n; b++){
if(!strcmp(registry.backends[b].name, name)){
//count instances
for(i = 0; registry.instances[b] && registry.instances[b][i]; i++){
}
*ninst = i;
if(!i){
*inst = NULL;
return 0;
}
*inst = calloc(i, sizeof(instance*));
if(!*inst){
LOG("Failed to allocate memory");
return 1;
}
memcpy(*inst, registry.instances[b], i * sizeof(instance*));
return 0;
}
}
return 1;
}
backend* backend_match(char* name){
size_t u;
for(u = 0; u < registry.n; u++){
if(!strcmp(registry.backends[u].name, name)){
return registry.backends + u;
}
}
return NULL;
}
instance* instance_match(char* name){
size_t u;
instance** iter = NULL;
for(u = 0; u < registry.n; u++){
for(iter = registry.instances[u]; iter && *iter; iter++){
if(!strcmp(name, (*iter)->name)){
return *iter;
}
}
}
return NULL;
}
struct timeval backend_timeout(){
size_t u;
uint32_t res, secs = 1, msecs = 0;
for(u = 0; u < registry.n; u++){
//only call interval if backend has instances
if(registry.instances[u] && registry.backends[u].interval){
res = registry.backends[u].interval();
if(res && (res / 1000) < secs){
DBGPF("Updating interval to %" PRIu32 " msecs by request from %s", res, registry.backends[u].name);
secs = res / 1000;
msecs = res % 1000;
}
else if(res && res / 1000 == secs && (res % 1000) < msecs){
DBGPF("Updating interval to %" PRIu32 " msecs by request from %s", res, registry.backends[u].name);
msecs = res % 1000;
}
}
}
struct timeval tv = {
secs,
msecs * 1000
};
return tv;
}
MM_API int mm_backend_register(backend b){
if(!backend_match(b.name)){
registry.backends = realloc(registry.backends, (registry.n + 1) * sizeof(backend));
registry.instances = realloc(registry.instances, (registry.n + 1) * sizeof(instance**));
if(!registry.backends || !registry.instances){
LOG("Failed to allocate memory");
registry.n = 0;
return 1;
}
registry.backends[registry.n] = b;
registry.instances[registry.n] = NULL;
registry.n++;
LOGPF("Registered backend %s", b.name);
return 0;
}
return 1;
}
int backends_start(){
int rv = 0, current;
instance** inst = NULL;
size_t n, u;
for(u = 0; u < registry.n; u++){
//skip backends without instances
if(!registry.instances[u]){
continue;
}
//fetch list of instances
if(mm_backend_instances(registry.backends[u].name, &n, &inst)){
LOGPF("Failed to fetch instance list for initialization of backend %s", registry.backends[u].name);
return 1;
}
//start the backend
current = registry.backends[u].start(n, inst);
if(current){
LOGPF("Failed to start backend %s", registry.backends[u].name);
}
//clean up
free(inst);
inst = NULL;
rv |= current;
}
return rv;
}
static void channels_free(){
size_t u, p;
for(u = 0; u < sizeof(channels.n) / sizeof(channels.n[0]); u++){
DBGPF("Cleaning up channel registry bucket %" PRIsize_t " with %" PRIsize_t " channels", u, channels.n[u]);
for(p = 0; p < channels.n[u]; p++){
DBGPF("Destroying channel %" PRIu64 " on instance %s", channels.entry[u][p]->ident, channels.entry[u][p]->instance->name);
//call the channel_free function if the backend supports it
if(channels.entry[u][p]->impl && channels.entry[u][p]->instance->backend->channel_free){
channels.entry[u][p]->instance->backend->channel_free(channels.entry[u][p]);
}
free(channels.entry[u][p]);
}
free(channels.entry[u]);
channels.entry[u] = NULL;
channels.n[u] = 0;
}
}
int backends_stop(){
size_t u, n;
instance** inst = NULL;
//channels before instances to support proper shutdown procedures
channels_free();
//shut down the registry
for(u = 0; u < registry.n; u++){
//fetch list of instances
if(mm_backend_instances(registry.backends[u].name, &n, &inst)){
LOGPF("Failed to fetch instance list for shutdown of backend %s", registry.backends[u].name);
inst = NULL;
n = 0;
}
registry.backends[u].shutdown(n, inst);
free(inst);
inst = NULL;
//free instances
for(inst = registry.instances[u]; inst && *inst; inst++){
free((*inst)->name);
(*inst)->name = NULL;
(*inst)->backend = NULL;
free(*inst);
}
free(registry.instances[u]);
registry.instances[u] = NULL;
}
free(registry.backends);
free(registry.instances);
registry.n = 0;
return 0;
}
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