lua-autoinc: lua box.auto_increment function added

mod/box/box.lua

@@ -241,6 +241,19 @@ function box.update_ol(space, ops_list, ...)
     return box.process(19, box.pack(format, unpack(args_list)))
 end
 
+-- Assumes that spaceno has a TREE int32 (NUM) primary key
+-- inserts a tuple after getting the next value of the
+-- primary key and returns it back to the user
+function box.auto_increment(spaceno, ...)
+    spaceno = tonumber(spaceno)
+    local max_tuple = box.space[spaceno].index[0].idx:max()
+    local max = -1
+    if max_tuple ~= nil then
+        max = box.unpack('i', max_tuple[0])
+    end
+    return box.insert(spaceno, max + 1, ...)
+end
+
 function box.on_reload_configuration()
     local index_mt = {}
     -- __len and __index

test/box_big/lua.result

@@ -310,3 +310,19 @@ lua box.space[17].index[1].idx:count()
 ---
 error: 'index.count(): one or more arguments expected'
 ...
+lua box.auto_increment(18, 'a')
+---
+ - 0: {'a'}
+...
+lua box.insert(18, 5)
+---
+ - 5: {}
+...
+lua box.auto_increment(18, 'b')
+---
+ - 6: {'b'}
+...
+lua box.auto_increment(18, 'c')
+---
+ - 7: {'c'}
+...

test/box_big/lua.test

@@ -106,3 +106,11 @@ exec admin "lua box.space[17].index[1].idx:count(2, 2)"
 exec admin "lua box.space[17].index[1].idx:count(3)"
 exec admin "lua box.space[17].index[1].idx:count(3, 3)"
 exec admin "lua box.space[17].index[1].idx:count()"
+
+#
+# Tests for lua box.auto_increment
+#
+exec admin "lua box.auto_increment(18, 'a')"
+exec admin "lua box.insert(18, 5)"
+exec admin "lua box.auto_increment(18, 'b')"
+exec admin "lua box.auto_increment(18, 'c')"

test/box_big/tarantool.cfg

@@ -226,3 +226,11 @@ space[17].index[1].key_field[0].fieldno = 1
 space[17].index[1].key_field[0].type = "NUM"
 space[17].index[1].key_field[1].fieldno = 2
 space[17].index[1].key_field[1].type = "NUM"
+
+# lua box.auto_increment() testing
+# http://bugs.launchpad.net/tarantool/+bug/1006354
+space[18].enabled = 1
+space[18].index[0].type = "TREE"
+space[18].index[0].unique = 1
+space[18].index[0].key_field[0].fieldno = 0
+space[18].index[0].key_field[0].type = "NUM"