Fix Channel memory leak;

Channels need to be removed from the global array/map when destroyed.

Note that this exposes an infinite loop in map_remove, which will
be fixed later.

Note also that Channel's are retained if they have any messages in
them, to prevent releasing a channel while it has pending messages.

src/api/l_thread_module.c

@@ -80,6 +80,7 @@ static int l_lovrThreadGetChannel(lua_State* L) {
   const char* name = luaL_checkstring(L, 1);
   Channel* channel = lovrThreadGetChannel(name);
   luax_pushtype(L, Channel, channel);
+  lovrRelease(Channel, channel);
   return 1;
 }
 

src/modules/thread/channel.c

@@ -15,18 +15,22 @@ struct Channel {
   size_t head;
   uint64_t sent;
   uint64_t received;
+  uint64_t hash;
 };
 
-Channel* lovrChannelCreate(void) {
+Channel* lovrChannelCreate(uint64_t hash) {
   Channel* channel = lovrAlloc(Channel);
   arr_init(&channel->messages);
   mtx_init(&channel->lock, mtx_plain | mtx_timed);
   cnd_init(&channel->cond);
+  channel->hash = hash;
   return channel;
 }
 
+extern void lovrThreadRemoveChannel(uint64_t hash);
 void lovrChannelDestroy(void* ref) {
   Channel* channel = ref;
+  lovrThreadRemoveChannel(channel->hash);
   lovrChannelClear(channel);
   arr_free(&channel->messages);
   mtx_destroy(&channel->lock);

src/modules/thread/channel.h

@@ -6,7 +6,7 @@
 struct Variant;
 
 typedef struct Channel Channel;
-Channel* lovrChannelCreate(void);
+Channel* lovrChannelCreate(uint64_t hash);
 void lovrChannelDestroy(void* ref);
 bool lovrChannelPush(Channel* channel, struct Variant* variant, double timeout, uint64_t* id);
 bool lovrChannelPop(Channel* channel, struct Variant* variant, double timeout);

src/modules/thread/thread.c

@@ -38,12 +38,23 @@ Channel* lovrThreadGetChannel(const char* name) {
   if (index == MAP_NIL) {
     index = state.channels.length;
     map_set(&state.channelMap, hash, index);
-    arr_push(&state.channels, lovrChannelCreate());
+    arr_push(&state.channels, lovrChannelCreate(hash));
   }
 
   return state.channels.data[index];
 }
 
+void lovrThreadRemoveChannel(uint64_t hash) {
+  uint64_t index = map_get(&state.channelMap, hash);
+
+  if (index == MAP_NIL) {
+    return;
+  }
+
+  map_remove(&state.channelMap, hash);
+  arr_splice(&state.channels, index, 1);
+}
+
 Thread* lovrThreadInit(Thread* thread, int (*runner)(void*), Blob* body) {
   lovrRetain(body);
   thread->runner = runner;

src/modules/thread/thread.h

@@ -1,6 +1,7 @@
 #include "data/blob.h"
 #include "lib/tinycthread/tinycthread.h"
 #include <stdbool.h>
+#include <stdint.h>
 
 #pragma once
 
@@ -18,6 +19,7 @@ typedef struct Thread {
 bool lovrThreadModuleInit(void);
 void lovrThreadModuleDestroy(void);
 struct Channel* lovrThreadGetChannel(const char* name);
+void lovrThreadRemoveChannel(uint64_t hash);
 
 Thread* lovrThreadInit(Thread* thread, int (*runner)(void*), Blob* body);
 #define lovrThreadCreate(...) lovrThreadInit(lovrAlloc(Thread), __VA_ARGS__)