From c452cb5b4a9c2b9c52e882557bb8c16a8476f512 Mon Sep 17 00:00:00 2001
From: Konstantin Osipov <kostja.osipov@gmail.com>
Date: Thu, 13 Oct 2011 01:08:58 +0400
Subject: [PATCH] Lua: implement tuple iterators and methods.
Add tuple::pairs() and tuple:next() implementation.
Update tuple metatable __index implementation to do
method lookup.
Fix a bug in box.unpack() where we wouldn't check that
lua_tolstring() can return NULL (which happens if nil
is on the stack).
Add tests.
---
core/tarantool_lua.m | 6 ++-
mod/box/box_lua.m | 112 ++++++++++++++++++++++++++++++++++---------
test/box/lua.result | 43 +++++++++++++++++
test/box/lua.test | 12 +++++
4 files changed, 149 insertions(+), 24 deletions(-)
diff --git a/core/tarantool_lua.m b/core/tarantool_lua.m
index db75c078bd..ac998e3807 100644
--- a/core/tarantool_lua.m
+++ b/core/tarantool_lua.m
@@ -165,6 +165,7 @@ lbox_unpack(struct lua_State *L)
int i = 2; /* first arg comes second */
int nargs = lua_gettop(L);
size_t size;
+ const char *str;
u32 u32buf;
while (*format) {
@@ -172,9 +173,10 @@ lbox_unpack(struct lua_State *L)
luaL_error(L, "box.unpack: argument count does not match the format");
switch (*format) {
case 'i':
- u32buf = * (u32 *) lua_tolstring(L, i, &size);
- if (size != sizeof(u32))
+ str = lua_tolstring(L, i, &size);
+ if (str == NULL || size != sizeof(u32))
luaL_error(L, "box.unpack('%c'): got %d bytes (expected: 4)", *format, (int) size);
+ u32buf = * (u32 *) str;
lua_pushnumber(L, u32buf);
break;
default:
diff --git a/mod/box/box_lua.m b/mod/box/box_lua.m
index 78f8d9f6bb..86cbb86613 100644
--- a/mod/box/box_lua.m
+++ b/mod/box/box_lua.m
@@ -104,17 +104,31 @@ lbox_tuple_len(struct lua_State *L)
return 1;
}
+/**
+ * Implementation of tuple __index metamethod.
+ *
+ * Provides operator [] access to individual fields for integer
+ * indexes, as well as searches and invokes metatable methods
+ * for strings.
+ */
static int
lbox_tuple_index(struct lua_State *L)
{
struct box_tuple *tuple = lua_checktuple(L, 1);
- int i = luaL_checkint(L, 2);
- if (i >= tuple->cardinality)
- luaL_error(L, "%s: index %d is out of bounds (0..%d)",
- tuplelib_name, i, tuple->cardinality-1);
- void *field = tuple_field(tuple, i);
- u32 len = load_varint32(&field);
- lua_pushlstring(L, field, len);
+ /* For integer indexes, implement [] operator */
+ if (lua_isnumber(L, 2)) {
+ int i = luaL_checkint(L, 2);
+ if (i >= tuple->cardinality)
+ luaL_error(L, "%s: index %d is out of bounds (0..%d)",
+ tuplelib_name, i, tuple->cardinality-1);
+ void *field = tuple_field(tuple, i);
+ u32 len = load_varint32(&field);
+ lua_pushlstring(L, field, len);
+ return 1;
+ }
+ /* If we got a string, try to find a method for it. */
+ lua_getmetatable(L, 1);
+ lua_getfield(L, -1, lua_tostring(L, 2));
return 1;
}
@@ -143,18 +157,62 @@ lbox_pushtuple(struct lua_State *L, struct box_tuple *tuple)
}
}
+/**
+ * Sequential access to tuple fields. Since tuple is a list-like
+ * structure, iterating over tuple fields is faster
+ * than accessing fields using an index.
+ */
+static int
+lbox_tuple_next(struct lua_State *L)
+{
+ struct box_tuple *tuple = lua_checktuple(L, 1);
+ int argc = lua_gettop(L) - 1;
+ u8 *field;
+ size_t len;
+
+ if (argc == 0 || (argc == 1 && lua_type(L, 2) == LUA_TNIL))
+ field = tuple->data;
+ else if (argc == 1 && lua_islightuserdata(L, 2))
+ field = lua_touserdata(L, 2);
+ else
+ luaL_error(L, "tuple.next(): bad arguments");
+
+ assert(field >= tuple->data);
+ if (field < tuple->data + tuple->bsize) {
+ len = load_varint32((void **) &field);
+ lua_pushlightuserdata(L, field + len);
+ lua_pushlstring(L, (char *) field, len);
+ return 2;
+ }
+ lua_pushnil(L);
+ return 1;
+}
+
+/** Iterator over tuple fields. Adapt lbox_tuple_next
+ * to Lua iteration conventions.
+ */
+static int
+lbox_tuple_pairs(struct lua_State *L)
+{
+ lua_pushcfunction(L, lbox_tuple_next);
+ lua_pushvalue(L, -2); /* tuple */
+ lua_pushnil(L);
+ return 3;
+}
+
static const struct luaL_reg lbox_tuple_meta [] = {
{"__gc", lbox_tuple_gc},
{"__len", lbox_tuple_len},
{"__index", lbox_tuple_index},
{"__tostring", lbox_tuple_tostring},
+ {"next", lbox_tuple_next},
+ {"pairs", lbox_tuple_pairs},
{NULL, NULL}
};
/* }}} */
-/**
- * {{{ Lua box.index library: access to spaces and indexes
+/** {{{ box.index Lua library: access to spaces and indexes
*/
static const char *indexlib_name = "box.index";
@@ -573,27 +631,37 @@ void box_lua_call(struct box_txn *txn __attribute__((unused)),
}
}
+/** A helper to register a single type metatable. */
+static void
+lua_register_type(struct lua_State *L, const char *type_name,
+ const struct luaL_reg *methods)
+{
+ luaL_newmetatable(L, type_name);
+ /*
+ * Conventionally, make the metatable point to itself
+ * in __index. If 'methods' contain a field for __index,
+ * this is a no-op.
+ */
+ lua_pushvalue(L, -1);
+ lua_setfield(L, -2, "__index");
+ lua_pushstring(L, type_name);
+ lua_setfield(L, -2, "__metatable");
+ luaL_register(L, NULL, methods);
+ lua_pop(L, 1);
+}
+
struct lua_State *
mod_lua_init(struct lua_State *L)
{
lua_atpanic(L, box_lua_panic);
/* box, box.tuple */
+ lua_register_type(L, tuplelib_name, lbox_tuple_meta);
luaL_register(L, "box", boxlib);
- luaL_newmetatable(L, tuplelib_name);
- lua_pushstring(L, tuplelib_name);
- lua_setfield(L, -2, "__metatable");
- luaL_register(L, NULL, lbox_tuple_meta);
- lua_pop(L, 2);
+ lua_pop(L, 1);
/* box.index */
- luaL_newmetatable(L, indexlib_name);
- /* Make the metatable point to itself in __index. */
- lua_pushvalue(L, -1);
- lua_setfield(L, -2, "__index");
- lua_pushstring(L, indexlib_name);
- lua_setfield(L, -2, "__metatable");
- luaL_register(L, NULL, lbox_index_meta);
+ lua_register_type(L, indexlib_name, lbox_index_meta);
luaL_register(L, "box.index", indexlib);
- lua_pop(L, 2);
+ lua_pop(L, 1);
/* Load box.lua */
if (luaL_dostring(L, &_binary_box_lua_start))
panic("Error loading box.lua: %s", lua_tostring(L, -1));
diff --git a/test/box/lua.result b/test/box/lua.result
index cc822e853a..71dd95f4f0 100644
--- a/test/box/lua.result
+++ b/test/box/lua.result
@@ -477,3 +477,46 @@ lua box.space[0]:delete('test')
---
- 1953719668: {'bye, world'}
...
+lua t=box.space[0]:insert('test')
+---
+...
+lua t:next('abcd')
+---
+error: 'Lua error: tuple.next(): bad arguments'
+...
+lua t:next(1)
+---
+error: 'Lua error: tuple.next(): bad arguments'
+...
+lua t:next(t)
+---
+error: 'Lua error: tuple.next(): bad arguments'
+...
+lua t:next(t:next())
+---
+error: 'Lua error: tuple.next(): bad arguments'
+...
+lua for k, v in t:pairs() do print(v) end
+---
+test
+...
+lua t=box.space[0]:replace('test', 'another field')
+---
+...
+lua for k, v in t:pairs() do print(v) end
+---
+test
+another field
+...
+lua t=box.space[0]:replace('test', 'another field', 'one more')
+---
+...
+lua for k, v in t:pairs() do print(v) end
+---
+test
+another field
+one more
+...
+lua box.space[0]:truncate()
+---
+...
diff --git a/test/box/lua.test b/test/box/lua.test
index c457b4b1e6..8fcd3fc58f 100644
--- a/test/box/lua.test
+++ b/test/box/lua.test
@@ -130,3 +130,15 @@ exec admin "lua #box.index.new(0,0)"
exec admin "lua box.space[0]:insert('test', 'hello world')"
exec admin "lua box.space[0]:update('test', '=p', 1, 'bye, world')"
exec admin "lua box.space[0]:delete('test')"
+# test tuple iterators
+exec admin "lua t=box.space[0]:insert('test')"
+exec admin "lua t:next('abcd')"
+exec admin "lua t:next(1)"
+exec admin "lua t:next(t)"
+exec admin "lua t:next(t:next())"
+exec admin "lua for k, v in t:pairs() do print(v) end"
+exec admin "lua t=box.space[0]:replace('test', 'another field')"
+exec admin "lua for k, v in t:pairs() do print(v) end"
+exec admin "lua t=box.space[0]:replace('test', 'another field', 'one more')"
+exec admin "lua for k, v in t:pairs() do print(v) end"
+exec admin "lua box.space[0]:truncate()"
--
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