io: add file:size() method

2 files changed, 58 insertions, 0 deletions

diff --git a/lem/io/core.c b/lem/io/core.c
index 672961f..f46319e 100644
--- a/lem/io/core.c
+++ b/lem/io/core.c
@@ -283,6 +283,9 @@ luaopen_lem_io_core(lua_State *L)
 	/* mt.write = <file_write> */
 	lua_pushcfunction(L, file_write);
 	lua_setfield(L, -2, "write");
+	/* mt.size = <file_size> */
+	lua_pushcfunction(L, file_size);
+	lua_setfield(L, -2, "size");
 	/* mt.seek = <file_seek> */
 	lua_pushcfunction(L, file_seek);
 	lua_setfield(L, -2, "seek");
diff --git a/lem/io/file.c b/lem/io/file.c
index 07985b8..2015f31 100644
--- a/lem/io/file.c
+++ b/lem/io/file.c
@@ -29,6 +29,9 @@ struct file {
 			size_t len;
 		} write;
 		struct {
+			off_t val;
+		} size;
+		struct {
 			off_t offset;
 			int whence;
 		} seek;
@@ -247,6 +250,58 @@ file_write(lua_State *T)
 }
 
 /*
+ * file:size() method
+ */
+static void
+file_size_work(struct lem_async *a)
+{
+	struct file *f = (struct file *)a;
+	struct stat st;
+
+	if (fstat(f->fd, &st)) {
+		f->ret = errno;
+	} else {
+		f->ret = 0;
+		f->size.val = st.st_size;
+	}
+}
+
+static void
+file_size_reap(struct lem_async *a)
+{
+	struct file *f = (struct file *)a;
+	lua_State *T = f->a.T;
+
+	f->a.T = NULL;
+
+	if (f->ret) {
+		lem_queue(T, io_strerror(T, f->ret));
+		return;
+	}
+
+	lua_pushnumber(T, f->size.val);
+	lem_queue(T, 1);
+}
+
+static int
+file_size(lua_State *T)
+{
+	struct file *f;
+
+	luaL_checktype(T, 1, LUA_TUSERDATA);
+	f = lua_touserdata(T, 1);
+	if (f->fd < 0)
+		return io_closed(T);
+	if (f->a.T != NULL)
+		return io_busy(T);
+
+	lem_async_do(&f->a, T, file_size_work, file_size_reap);
+
+	lua_settop(T, 1);
+	return lua_yield(T, 1);
+}
+
+/*
  * file:seek() method
  */
 static void