From 8a28aa8b1c9302422eab93e7565e85747ed2670e Mon Sep 17 00:00:00 2001
From: Maria <marianneliash@gmail.com>
Date: Thu, 12 Sep 2019 16:55:53 +0300
Subject: [PATCH] lua: keeping the pointer type in msgpackffi.decode()
Method decode_unchecked returns two values - the one that has
been decoded and a pointer to the new position within the buffer
given as a parameter. The type of returned pointer used to be
cdata<unsigned char *> and it was not possible to assign returned
value to buf.rpos due to the following error:
> cannot convert 'const unsigned char *' to 'char *'
The patch fixes this by making decode_unchecked method return either
cdata<char *> or cdata<const char *> depending on the given parameter.
Closes #3926
(cherry picked from commit 84bcba52a84852870726e1a4d19b3768c0bde7a7)
---
src/lua/msgpackffi.lua | 12 +++++----
test/app-tap/msgpackffi.test.lua | 42 +++++++++++++++++++++++++++++++-
2 files changed, 48 insertions(+), 6 deletions(-)
diff --git a/src/lua/msgpackffi.lua b/src/lua/msgpackffi.lua
index 63d9b33b7c..051011dd9f 100644
--- a/src/lua/msgpackffi.lua
+++ b/src/lua/msgpackffi.lua
@@ -9,7 +9,7 @@ local uint8_ptr_t = ffi.typeof('uint8_t *')
local uint16_ptr_t = ffi.typeof('uint16_t *')
local uint32_ptr_t = ffi.typeof('uint32_t *')
local uint64_ptr_t = ffi.typeof('uint64_t *')
-local const_char_ptr_t = ffi.typeof('const char *')
+local char_ptr_t = ffi.typeof('char *')
ffi.cdef([[
char *
@@ -564,17 +564,19 @@ end
local function decode_unchecked(str, offset)
if type(str) == "string" then
offset = check_offset(offset, #str)
- local buf = ffi.cast(const_char_ptr_t, str)
+ local buf = ffi.cast(char_ptr_t, str)
bufp[0] = buf + offset - 1
local r = decode_r(bufp)
return r, bufp[0] - buf + 1
- elseif ffi.istype(const_char_ptr_t, str) then
+ elseif ffi.istype(char_ptr_t, str) then
+ -- Note: ffi.istype() ignores the const qualifier, so both
+ -- (char *) and (const char *) buffers are valid.
bufp[0] = str
local r = decode_r(bufp)
- return r, bufp[0]
+ return r, ffi.cast(ffi.typeof(str), bufp[0])
else
error("msgpackffi.decode_unchecked(str, offset) -> res, new_offset | "..
- "msgpackffi.decode_unchecked(const char *buf) -> res, new_buf")
+ "msgpackffi.decode_unchecked([const] char *buf) -> res, new_buf")
end
end
diff --git a/test/app-tap/msgpackffi.test.lua b/test/app-tap/msgpackffi.test.lua
index e82c7401ac..bb9826580a 100755
--- a/test/app-tap/msgpackffi.test.lua
+++ b/test/app-tap/msgpackffi.test.lua
@@ -4,6 +4,7 @@ package.path = "lua/?.lua;"..package.path
local tap = require('tap')
local common = require('serializer_test')
+local ffi = require('ffi')
local function is_map(s)
local b = string.byte(string.sub(s, 1, 1))
@@ -115,9 +116,48 @@ local function test_other(test, s)
encode_max_depth = max_depth})
end
+-- gh-3926: Ensure that a returned pointer has the same cdata type
+-- as passed argument.
+local function test_decode_buffer(test, s)
+ local cases = {
+ {
+ 'decode_unchecked(cdata<const char *>)',
+ data = ffi.cast('const char *', '\x93\x01\x02\x03'),
+ exp_res = {1, 2, 3},
+ exp_rewind = 4,
+ },
+ {
+ 'decode_unchecked(cdata<char *>)',
+ data = ffi.cast('char *', '\x93\x01\x02\x03'),
+ exp_res = {1, 2, 3},
+ exp_rewind = 4,
+ },
+ }
+
+ test:plan(#cases)
+
+ for _, case in ipairs(cases) do
+ test:test(case[1], function(test)
+ test:plan(4)
+ local res, res_buf = s.decode_unchecked(case.data)
+ test:is_deeply(res, case.exp_res, 'verify result')
+ local rewind = res_buf - case.data
+ test:is(rewind, case.exp_rewind, 'verify resulting buffer')
+ -- test:iscdata() is not sufficient here, because it
+ -- ignores 'const' qualifier (because of using
+ -- ffi.istype()).
+ test:is(type(res_buf), 'cdata', 'verify resulting buffer type')
+ local data_ctype = tostring(ffi.typeof(case.data))
+ local res_buf_ctype = tostring(ffi.typeof(res_buf))
+ test:is(res_buf_ctype, data_ctype, 'verify resulting buffer ctype')
+ end)
+ end
+end
+
+
tap.test("msgpackffi", function(test)
local serializer = require('msgpackffi')
- test:plan(9)
+ test:plan(10)
test:test("unsigned", common.test_unsigned, serializer)
test:test("signed", common.test_signed, serializer)
test:test("double", common.test_double, serializer)
--
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