Add an artwork "stash" in cache.c so we avoid making redundant http artwork requests

src/artwork.c

@@ -684,13 +684,13 @@ artwork_get_player_image(struct evbuffer *evbuf, char *path)
   struct keyval *kv;
   const char *content_type;
   char *url;
+  int format;
   int id;
   int len;
-  int ret;
 
   DPRINTF(E_DBG, L_ART, "Trying internet stream artwork in %s\n", path);
 
-  ret = 0;
+  format = 0;
 
   id = db_file_id_bypath(path);
   if (!id)
@@ -704,6 +704,10 @@ artwork_get_player_image(struct evbuffer *evbuf, char *path)
   if ((len < 14) || (len > PATH_MAX)) // Can't be shorter than http://a/1.jpg
     goto out_url;
 
+  cache_artwork_read(evbuf, url, &format);
+  if (format > 0)
+    goto out_url;
+
   kv = keyval_alloc();
   if (!kv)
     goto out_url;
@@ -718,12 +722,16 @@ artwork_get_player_image(struct evbuffer *evbuf, char *path)
 
   content_type = keyval_get(kv, "Content-Type");
   if (content_type && (strcmp(content_type, "image/jpeg") == 0))
-    ret = ART_FMT_JPEG;
+    format = ART_FMT_JPEG;
   else if (content_type && (strcmp(content_type, "image/png") == 0))
-    ret = ART_FMT_PNG;
+    format = ART_FMT_PNG;
 
-  if (ret)
+  if (format)
-    DPRINTF(E_DBG, L_ART, "Found internet stream artwork in %s (%s)\n", url, content_type);
+    {
+      DPRINTF(E_DBG, L_ART, "Found internet stream artwork in %s (%s)\n", url, content_type);
+
+      cache_artwork_stash(evbuf, url, format);
+    }
 
  out_kv:
   keyval_clear(kv);
@@ -732,7 +740,7 @@ artwork_get_player_image(struct evbuffer *evbuf, char *path)
  out_url:
   free(url);
 
-  return ret;
+  return format;
 }
 
 #if LIBAVFORMAT_VERSION_MAJOR >= 55 || (LIBAVFORMAT_VERSION_MAJOR == 54 && LIBAVFORMAT_VERSION_MINOR >= 6)

src/cache.c

@@ -60,7 +60,7 @@ struct cache_command
 
     char *path;  // artwork path
     int type;    // individual or group artwork
-    int64_t peristentid;
+    int64_t persistentid;
     int max_w;
     int max_h;
     int format;
@@ -91,6 +91,15 @@ static int g_initialized;
 static sqlite3 *g_db_hdl;
 static char *g_db_path;
 
+// Global artwork stash
+struct stash
+{
+  char *path;
+  int format;
+  size_t size;
+  uint8_t *data;
+} g_stash;
+
 // After being triggered wait 60 seconds before rebuilding cache
 static struct timeval g_wait = { 60, 0 };
 
@@ -1067,7 +1076,7 @@ cache_artwork_add_impl(struct cache_command *cmd)
   data = EVBUFFER_DATA(cmd->arg.evbuf);
 #endif
 
-  sqlite3_bind_int64(stmt, 1, cmd->arg.peristentid);
+  sqlite3_bind_int64(stmt, 1, cmd->arg.persistentid);
   sqlite3_bind_int(stmt, 2, cmd->arg.max_w);
   sqlite3_bind_int(stmt, 3, cmd->arg.max_h);
   sqlite3_bind_int(stmt, 4, cmd->arg.format);
@@ -1118,7 +1127,7 @@ cache_artwork_get_impl(struct cache_command *cmd)
   int datalen;
   int ret;
 
-  query = sqlite3_mprintf(Q_TMPL, cmd->arg.type, cmd->arg.peristentid, cmd->arg.max_w, cmd->arg.max_h);
+  query = sqlite3_mprintf(Q_TMPL, cmd->arg.type, cmd->arg.persistentid, cmd->arg.max_w, cmd->arg.max_h);
   if (!query)
     {
       DPRINTF(E_LOG, L_CACHE, "Out of memory for query string\n");
@@ -1184,6 +1193,52 @@ cache_artwork_get_impl(struct cache_command *cmd)
 #undef Q_TMPL
 }
 
+static int
+cache_artwork_stash_impl(struct cache_command *cmd)
+{
+  /* Clear current stash */
+  if (g_stash.path)
+    {
+      free(g_stash.path);
+      free(g_stash.data);
+      memset(&g_stash, 0, sizeof(struct stash));
+    }
+
+  g_stash.size = evbuffer_get_length(cmd->arg.evbuf);
+  g_stash.data = malloc(g_stash.size);
+  if (!g_stash.data)
+    {
+      DPRINTF(E_LOG, L_CACHE, "Out of memory for artwork stash data\n");
+      return -1;
+    }
+
+  g_stash.path = strdup(cmd->arg.path);
+  if (!g_stash.path)
+    {
+      DPRINTF(E_LOG, L_CACHE, "Out of memory for artwork stash path\n");
+      free(g_stash.data);
+      return -1;
+    }
+
+  g_stash.format = cmd->arg.format;
+
+  return evbuffer_copyout(cmd->arg.evbuf, g_stash.data, g_stash.size);
+}
+
+static int
+cache_artwork_read_impl(struct cache_command *cmd)
+{
+  cmd->arg.format = 0;
+
+  if (!g_stash.path || !g_stash.data || (strcmp(g_stash.path, cmd->arg.path) != 0))
+    return -1;
+
+  cmd->arg.format = g_stash.format;
+
+  DPRINTF(E_DBG, L_CACHE, "Stash hit (format %d, size %d): %s\n", g_stash.format, g_stash.size, g_stash.path);  
+
+  return evbuffer_add(cmd->arg.evbuf, g_stash.data, g_stash.size);
+}
 
 static void *
 cache(void *arg)
@@ -1482,7 +1537,7 @@ cache_artwork_add(int type, int64_t persistentid, int max_w, int max_h, int form
 
   cmd.func = cache_artwork_add_impl;
   cmd.arg.type = type;
-  cmd.arg.peristentid = persistentid;
+  cmd.arg.persistentid = persistentid;
   cmd.arg.max_w = max_w;
   cmd.arg.max_h = max_h;
   cmd.arg.format = format;
@@ -1523,7 +1578,7 @@ cache_artwork_get(int type, int64_t persistentid, int max_w, int max_h, int *cac
 
   cmd.func = cache_artwork_get_impl;
   cmd.arg.type = type;
-  cmd.arg.peristentid = persistentid;
+  cmd.arg.persistentid = persistentid;
   cmd.arg.max_w = max_w;
   cmd.arg.max_h = max_h;
   cmd.arg.evbuf = evbuf;
@@ -1538,6 +1593,68 @@ cache_artwork_get(int type, int64_t persistentid, int max_w, int max_h, int *cac
   return ret;
 }
 
+/*
+ * Put an artwork image in the in-memory stash (the previous will be deleted)
+ *
+ * @param evbuf event buffer with the cached image to cache
+ * @param path the source (url) of the image to stash
+ * @param format the format of the image
+ * @return 0 if successful, -1 if an error occurred
+ */
+int
+cache_artwork_stash(struct evbuffer *evbuf, char *path, int format)
+{
+  struct cache_command cmd;
+  int ret;
+
+  if (!g_initialized)
+    return -1;
+
+  command_init(&cmd);
+
+  cmd.func = cache_artwork_stash_impl;
+  cmd.arg.evbuf = evbuf;
+  cmd.arg.path = path;
+  cmd.arg.format = format;
+
+  ret = sync_command(&cmd);
+
+  command_deinit(&cmd);
+
+  return ret;
+}
+
+/*
+ * Read the cached artwork image in the in-memory stash into evbuffer
+ *
+ * @param evbuf event buffer filled by this function with the cached image
+ * @param path this function will check that the path matches the cached image's path
+ * @param format set by this function to the format of the image
+ * @return 0 if successful, -1 if an error occurred
+ */
+int
+cache_artwork_read(struct evbuffer *evbuf, char *path, int *format)
+{
+  struct cache_command cmd;
+  int ret;
+
+  if (!g_initialized)
+    return -1;
+
+  command_init(&cmd);
+
+  cmd.func = cache_artwork_read_impl;
+  cmd.arg.evbuf = evbuf;
+  cmd.arg.path = path;
+
+  ret = sync_command(&cmd);
+
+  *format = cmd.arg.format;
+
+  command_deinit(&cmd);
+
+  return ret;
+}
 
 
 /* -------------------------- Cache general API --------------------------- */

src/cache.h

@@ -45,6 +45,11 @@ cache_artwork_add(int type, int64_t persistentid, int max_w, int max_h, int form
 int
 cache_artwork_get(int type, int64_t persistentid, int max_w, int max_h, int *cached, int *format, struct evbuffer *evbuf);
 
+int
+cache_artwork_stash(struct evbuffer *evbuf, char *path, int format);
+
+int
+cache_artwork_read(struct evbuffer *evbuf, char *path, int *format);
 
 /* ---------------------------- Cache API  --------------------------- */