cursor: Add support for cursor operations

README.md

@@ -57,12 +57,26 @@ code, message, value = db:get("my_column_family", "key")
 -- Delete the key-value pair
 db:delete("my_column_family", "key")
 
+-- Create a cursor for iterating over key-value pairs
+code, message, cursor = db:cursor_init("my_column_family")
+assert(code == 0, message)
+
+-- Move cursor to next key-value pair
+code, message = cursor:next()
+assert(code == 0, message)
+
+-- Get current key-value pair
+code, message, value = cursor:get()
+assert(code == 0, message)
+
+-- Move cursor to previous key-value pair
+code, message = cursor:prev()
+assert(code == 0, message)
+
+-- Free cursor when done
+code, message = cursor:free()
+assert(code == 0, message)
+
 --- Close the database
 lib.close(db)
-```
-
-#### Test lua wrapper-library
-```bash
-cd build
-lua ../test_lua.lua
-```
+```

spec/tidesdb_spec.lua

@@ -44,6 +44,17 @@ local value = "value"
 local value_size = string.len(value)
 local ttl = 10
 
+-- Setup test directory
+os.execute("rm -rf " .. directory)
+os.execute("mkdir -p " .. directory)
+os.execute("chmod 777 " .. directory)
+
+describe("load", function()
+  it("should open tidesdb_lua", function()
+    assert.truthy(require("libtidesdb_lua"))
+  end)
+end)
+
 describe("open and close", function()
   it("should open and close db", function()
     assert.truthy(lib.open(directory))
@@ -233,3 +244,69 @@ describe("transactions put and delete", function()
     assert.is_equal(0, code)
   end)
 end)
+
+describe("cursor operations", function()
+  it("should perform cursor operations", function()
+    assert.truthy(lib.open(directory))
+
+    local code, message, db = lib.open(directory)
+    assert.is_equal(0, code)
+
+    code, message = db:create_column_family(name,
+                                            threshold,
+                                            max_skip_list,
+                                            prob_skip_list,
+                                            enable_compression,
+                                            compression_algo,
+                                            enable_bloom_filter)
+    assert.is_equal(0, code)
+
+    -- Insert test data
+    for i=1,5 do
+      code, message = db:put(name, "key" .. i, "value" .. i, ttl)
+      assert.is_equal(0, code)
+    end
+
+    -- Create cursor
+    code, message, cursor = db:cursor_init(name)
+    assert.is_equal(0, code)
+
+    -- Test next operations
+    for i=1,5 do
+      code, message, key, value = cursor:get()
+      assert.is_equal(0, code)
+      assert.is_equal(key, "key" .. i)
+      assert.is_equal(value, "value" .. i)
+      code, message = cursor:next()
+      if i ~= 5 then
+        assert.is_equal(0, code)
+      end
+    end
+
+    -- Position cursor at last element
+    code, message = cursor:prev()
+    assert.is_equal(0, code)
+
+    -- Test prev operations
+    for i=5,1,-1 do
+      code, message, key, value = cursor:get()
+      assert.is_equal(0, code)
+      assert.is_equal(key, "key" .. i)
+      assert.is_equal(value, "value" .. i)
+      code, message = cursor:prev()
+      if i ~= 1 then
+        assert.is_equal(0, code)
+      end
+    end
+
+    -- Free cursor
+    code, message = cursor:free()
+    assert.is_equal(0, code)
+
+    code, message = db:drop_column_family(name)
+    assert.is_equal(0, code)
+
+    local code, message, db = lib.close(db)
+    assert.is_equal(0, code)
+  end)
+end)

src/tidesdb-lua.c

@@ -72,10 +72,14 @@ static int txn_commit(lua_State *L);
 static int txn_rollback(lua_State *L);
 static int txn_free(lua_State *L);
 
+static int cursor_init(lua_State *L);
+static int cursor_next(lua_State *L);
+static int cursor_prev(lua_State *L);
+static int cursor_get(lua_State *L);
+static int cursor_free(lua_State *L);
+
 static const luaL_Reg regs_tidesdb_lib_lua[] = {
-    {"open", db_open},
-    {"close", db_close},
-    {"txn_begin", txn_begin},
+    {"open", db_open}, {"close", db_close}, {"txn_begin", txn_begin}, {"cursor_init", cursor_init},
     {NULL, NULL},
 };
 
@@ -88,6 +92,7 @@ static const luaL_Reg regs_tidesdb_lua[] = {
     {"compact_sstables", compact_sstables},
     {"list_column_families", list_column_families},
     {"txn_begin", txn_begin},
+    {"cursor_init", cursor_init},
     {NULL, NULL},
 };
 
@@ -96,6 +101,11 @@ static const luaL_Reg regs_tidesdb_txn_lua[] = {
     {"rollback", txn_rollback}, {"free", txn_free},     {NULL, NULL},
 };
 
+static const luaL_Reg regs_tidesdb_curs_lua[] = {
+    {"next", cursor_next}, {"prev", cursor_prev}, {"get", cursor_get},
+    {"free", cursor_free}, {NULL, NULL},
+};
+
 static int db_open(lua_State *L)
 {
     const char *directory = luaL_checkstring(L, 1);
@@ -293,6 +303,87 @@ static int txn_free(lua_State *L)
     LUA_RET_CODE()
 }
 
+static int cursor_init(lua_State *L)
+{
+    lua_getfield(L, 1, "self_db");
+    tidesdb_t *db = lua_touserdata(L, -1);
+    const char *column_family = luaL_checkstring(L, 2);
+    tidesdb_cursor_t *curs = NULL;
+
+    tidesdb_err_t *ret = tidesdb_cursor_init(db, column_family, &curs);
+    if (ret)
+    {
+        lua_pushinteger(L, ret->code);
+        lua_pushstring(L, ret->message);
+        tidesdb_err_free(ret);
+        return 2;
+    }
+    else
+    {
+        lua_pushinteger(L, 0);
+        lua_pushstring(L, "OK");
+
+        lua_newtable(L);
+        luaL_setfuncs(L, regs_tidesdb_curs_lua, 0);
+        lua_pushlightuserdata(L, curs);
+        lua_setfield(L, -2, "self_curs");
+        return 3;
+    }
+}
+
+static int cursor_next(lua_State *L)
+{
+    lua_getfield(L, 1, "self_curs");
+    tidesdb_cursor_t *curs = lua_touserdata(L, -1);
+    tidesdb_err_t *ret = tidesdb_cursor_next(curs);
+    LUA_RET_CODE()
+}
+
+static int cursor_prev(lua_State *L)
+{
+    lua_getfield(L, 1, "self_curs");
+    tidesdb_cursor_t *curs = lua_touserdata(L, -1);
+    tidesdb_err_t *ret = tidesdb_cursor_prev(curs);
+    LUA_RET_CODE()
+}
+
+static int cursor_get(lua_State *L)
+{
+    lua_getfield(L, 1, "self_curs");
+    tidesdb_cursor_t *curs = lua_touserdata(L, -1);
+    uint8_t *key = NULL;
+    size_t key_size = 0;
+    uint8_t *value = NULL;
+    size_t value_size = 0;
+
+    tidesdb_err_t *ret = tidesdb_cursor_get(curs, &key, &key_size, &value, &value_size);
+    if (ret)
+    {
+        lua_pushinteger(L, ret->code);
+        lua_pushstring(L, ret->message);
+        tidesdb_err_free(ret);
+        return 2;
+    }
+    else
+    {
+        lua_pushinteger(L, 0);
+        lua_pushstring(L, "OK");
+        lua_pushlstring(L, (char *)key, key_size);
+        lua_pushlstring(L, (char *)value, value_size);
+        free(key);
+        free(value);
+        return 4;
+    }
+}
+
+static int cursor_free(lua_State *L)
+{
+    lua_getfield(L, 1, "self_curs");
+    tidesdb_cursor_t *curs = lua_touserdata(L, -1);
+    tidesdb_err_t *ret = tidesdb_cursor_free(curs);
+    LUA_RET_CODE()
+}
+
 LUALIB_API int luaopen_libtidesdb_lua(lua_State *L)
 {
     luaL_newlib(L, regs_tidesdb_lib_lua);