Avoid cache regeneration triggering during db_query_run (in case the query is long running, like db_files_update_songalbumid might be)

src/cache.c

@@ -103,6 +103,7 @@ struct stash
 
 // After being triggered wait 60 seconds before rebuilding cache
 static struct timeval g_wait = { 60, 0 };
+static int g_suspended;
 
 // The user may configure a threshold (in msec), and queries slower than
 // that will have their reply cached
@@ -936,6 +937,30 @@ cache_daap_update_timer(struct cache_command *cmd)
   return 0;
 }
 
+static int
+cache_daap_suspend_timer(struct cache_command *cmd)
+{
+  if (!g_cacheev)
+    return -1;
+
+  g_suspended = evtimer_pending(g_cacheev, NULL);
+  if (g_suspended)
+    evtimer_del(g_cacheev);
+
+  return 0;
+}
+
+static int
+cache_daap_resume_timer(struct cache_command *cmd)
+{
+  if (!g_cacheev)
+    return -1;
+
+  if (g_suspended)
+    evtimer_add(g_cacheev, &g_wait);
+
+  return 0;
+}
 
 /*
  * Updates cached timestamps to current time for all cache entries for the given path, if the file was not modfied
@@ -1404,6 +1429,54 @@ cache_daap_trigger(void)
   nonblock_command(cmd);
 }
 
+void
+cache_daap_suspend(void)
+{
+  struct cache_command *cmd;
+
+  if (!g_initialized)
+    return;
+
+  cmd = (struct cache_command *)malloc(sizeof(struct cache_command));
+  if (!cmd)
+    {
+      DPRINTF(E_LOG, L_CACHE, "Could not allocate cache_command\n");
+      return;
+    }
+
+  memset(cmd, 0, sizeof(struct cache_command));
+
+  cmd->nonblock = 1;
+
+  cmd->func = cache_daap_suspend_timer;
+
+  nonblock_command(cmd);
+}
+
+void
+cache_daap_resume(void)
+{
+  struct cache_command *cmd;
+
+  if (!g_initialized)
+    return;
+
+  cmd = (struct cache_command *)malloc(sizeof(struct cache_command));
+  if (!cmd)
+    {
+      DPRINTF(E_LOG, L_CACHE, "Could not allocate cache_command\n");
+      return;
+    }
+
+  memset(cmd, 0, sizeof(struct cache_command));
+
+  cmd->nonblock = 1;
+
+  cmd->func = cache_daap_resume_timer;
+
+  nonblock_command(cmd);
+}
+
 int
 cache_daap_get(const char *query, struct evbuffer *evbuf)
 {

src/cache.h

@@ -15,6 +15,12 @@
 void
 cache_daap_trigger(void);
 
+void
+cache_daap_suspend(void);
+
+void
+cache_daap_resume(void);
+
 int
 cache_daap_get(const char *query, struct evbuffer *evbuf);
 

src/db.c

@@ -1589,6 +1589,9 @@ db_query_run(char *query, int free, int cache_update)
 
   DPRINTF(E_DBG, L_DB, "Running query '%s'\n", query);
 
+  /* If the query will be long running we don't want the cache to start regenerating */
+  cache_daap_suspend();
+
   ret = db_exec(query, &errmsg);
   if (ret != SQLITE_OK)
     DPRINTF(E_LOG, L_DB, "Error '%s' while runnning '%s'\n", errmsg, query);
@@ -1600,6 +1603,8 @@ db_query_run(char *query, int free, int cache_update)
 
   if (cache_update)
     cache_daap_trigger();
+  else
+    cache_daap_resume();
 
   return ((ret != SQLITE_OK) ? -1 : 0);
 }