util.dbuffer: Add efficient shortcuts for discard() in certain cases
If the buffer is already empty, nothing to do. If we're throwing away the
whole buffer, we can just empty it and avoid read_chunk() (which in turn
may collapse()). These shortcuts are much more efficient.
local serialization = require "util.serialization";
describe("util.serialization", function ()
describe("serialize", function ()
it("makes a string", function ()
assert.is_string(serialization.serialize({}));
assert.is_string(serialization.serialize(nil));
assert.is_string(serialization.serialize(1));
assert.is_string(serialization.serialize(true));
end);
it("rejects function by default", function ()
assert.has_error(function ()
serialization.serialize(function () end)
end);
end);
it("makes a string in debug mode", function ()
assert.is_string(serialization.serialize(function () end, "debug"));
end);
it("rejects cycles", function ()
assert.has_error(function ()
local t = {}
t[t] = { t };
serialization.serialize(t)
end);
-- also with multirefs allowed
assert.has_error(function ()
local t = {}
t[t] = { t };
serialization.serialize(t, { multirefs = true })
end);
end);
it("rejects multiple references to same table", function ()
assert.has_error(function ()
local t1 = {};
local t2 = { t1, t1 };
serialization.serialize(t2, { multirefs = false });
end);
end);
it("optionally allows multiple references to same table", function ()
assert.has_error(function ()
local t1 = {};
local t2 = { t1, t1 };
serialization.serialize(t2, { multirefs = true });
end);
end);
it("roundtrips", function ()
local function test(data)
local serialized = serialization.serialize(data);
assert.is_string(serialized);
local deserialized, err = serialization.deserialize(serialized);
assert.same(data, deserialized, err);
end
test({});
test({hello="world"});
test("foobar")
test("\0\1\2\3");
test("nödåtgärd");
test({1,2,3,4});
test({foo={[100]={{"bar"},{baz=1}}}});
test({["goto"] = {["function"]={["do"]="keywords"}}});
end);
it("can serialize with metatables", function ()
local s = serialization.new({ freeze = true });
local t = setmetatable({ a = "hi" }, { __freeze = function (t) return { t.a } end });
local rt = serialization.deserialize(s(t));
assert.same({"hi"}, rt);
end);
end);
end);