update: don't export updateDirectory()

If the user requests database update during startup, call
directory_update_init().  This should be changed to fully asynchronous
update later.

For this to work, main_notify has to be initialized before db_init().

src/database.c

@@ -29,6 +29,7 @@
 #include "utils.h"
 #include "dbUtils.h"
 #include "update.h"
+#include "main_notify.h"
 
 #include <assert.h>
 #include <string.h>
@@ -40,8 +41,19 @@ static time_t directory_dbModTime;
 void
 db_init(void)
 {
+	int ret;
+
 	music_root = directory_new("", NULL);
-	updateDirectory(music_root);
+
+	ret = directory_update_init(NULL);
+	if (ret < 0)
+		FATAL("directory update failed\n");
+
+	do {
+		wait_main_task();
+		reap_update_task();
+	} while (isUpdatingDB());
+
 	stats.numberOfSongs = countSongsIn(NULL);
 	stats.dbPlayTime = sumSongTimesIn(NULL);
 }

src/main.c

@@ -412,6 +412,8 @@ int main(int argc, char *argv[])
 	initPlaylist();
 	decoder_plugin_init_all();
 
+	init_main_notify();
+
 	openDB(&options, argv[0]);
 
 	initCommands();
@@ -429,7 +431,6 @@ int main(int argc, char *argv[])
 
 	daemonize(&options);
 
-	init_main_notify();
 	setup_log_output(options.stdOutput);
 
 	initSigHandlers();

src/update.c

@@ -30,6 +30,12 @@
 #include "condition.h"
 #include "update.h"
 
+enum update_return {
+	UPDATE_RETURN_ERROR = -1,
+	UPDATE_RETURN_NOUPDATE = 0,
+	UPDATE_RETURN_UPDATED = 1
+};
+
 enum update_progress {
 	UPDATE_PROGRESS_IDLE = 0,
 	UPDATE_PROGRESS_RUNNING = 1,
@@ -203,6 +209,9 @@ inodeFoundInParent(struct directory *parent, ino_t inode, dev_t device)
 	return 0;
 }
 
+static enum update_return
+updateDirectory(struct directory *directory);
+
 static enum update_return
 addSubDirectoryToDirectory(struct directory *directory,
 			   const char *name, const struct stat *st)
@@ -280,7 +289,7 @@ static int skip_path(const char *path)
 	return (path[0] == '.' || strchr(path, '\n')) ? 1 : 0;
 }
 
-enum update_return
+static enum update_return
 updateDirectory(struct directory *directory)
 {
 	bool was_empty = directory_is_empty(directory);

src/update.h

@@ -20,19 +20,8 @@
 #ifndef UPDATE_H
 #define UPDATE_H
 
-struct directory;
-
-enum update_return {
-	UPDATE_RETURN_ERROR = -1,
-	UPDATE_RETURN_NOUPDATE = 0,
-	UPDATE_RETURN_UPDATED = 1
-};
-
 int isUpdatingDB(void);
 
-enum update_return
-updateDirectory(struct directory *directory);
-
 /*
  * returns the non-negative update job ID on success,
  * returns -1 if busy