From 17963c9082cb3a391e7f8df0dba8582a599400ac Mon Sep 17 00:00:00 2001
From: Alexey Melnichuk <alexeymelnichuck@gmail.com>
Date: Mon, 5 Sep 2016 14:49:51 +0300
Subject: [PATCH] Add. Protected formatter.

---
 lua/log/formatter/pformat.lua    | 91 ++++++++++++++++++++++++++++++++
 rockspecs/lua-log-scm-0.rockspec |  2 +
 test/test_basic.lua              | 71 +++++++++++++++++++++++++
 3 files changed, 164 insertions(+)
 create mode 100644 lua/log/formatter/pformat.lua

diff --git a/lua/log/formatter/pformat.lua b/lua/log/formatter/pformat.lua
new file mode 100644
index 0000000..e79028a
--- /dev/null
+++ b/lua/log/formatter/pformat.lua
@@ -0,0 +1,91 @@
+local lpeg   = require "lpeg"
+local table  = require "table"
+local string = require "string"
+
+local unpack = unpack or table.unpack
+
+local HAS_A_FORMAT = pcall(string.format, '%a' , 10)
+
+local P, C, Cs, Ct, Cp, S, R = lpeg.P, lpeg.C, lpeg.Cs, lpeg.Ct, lpeg.Cp, lpeg.S, lpeg.R
+
+local any   = P(1)
+local empty = P(0)
+
+local esc   = P'%%'
+local flags = S'-+ #0'
+local digit = R'09'
+
+local fsym         = S('cdiouxXeEfgGqs' .. (HAS_A_FORMAT and 'aA' or ''))
+local width        = digit * digit + digit
+local precision    = P'.' * (digit * digit + digit)
+local format       = (flags + empty) * (width + empty) * (precision + empty) * (P'.' + empty)
+local valid_format = P'%' * format * fsym
+local valid_format_capture = Cs(valid_format)
+
+local any_fsym     = any - (flags + digit + P'.')
+local any_format   = P'%' * (flags + digit + P'.')^0 * any_fsym
+
+local types = {
+  c = 'number';
+  d = 'number';
+  i = 'number';
+  o = 'number';
+  u = 'number';
+  x = 'number';
+  X = 'number';
+  a = 'number';
+  A = 'number';
+  e = 'number';
+  E = 'number';
+  f = 'number';
+  g = 'number';
+  G = 'number';
+  q = 'string';
+  s = 'string';
+}
+
+local function safe_format(protect_only_args, fmt, ...)
+  local n, args = 0, {...}
+
+  local function fix_fmt(f)
+    local fmt = valid_format_capture:match(f)
+
+    if not fmt then
+      if protect_only_args then return end
+      return '%' .. f
+    end
+
+    local typ = string.sub(fmt, -1)
+
+    n = n + 1
+
+    if types[typ] ~= type( args[n] ) then
+      args[n], fmt = tostring(args[n]), '%s'
+    end
+
+    return fmt
+  end
+
+  local pattern = Cs((esc + any_format / fix_fmt + any) ^ 0)
+  fmt = pattern:match(fmt)
+
+  return string.format(fmt, unpack(args, 1, n))
+end
+
+local function buld_formatter(protect_only_args, no_warning)
+  return function(...)
+    local ok, msg = pcall(string.format, ...)
+    if not ok then
+      local err = msg
+      msg = safe_format(protect_only_args, ...)
+      if not no_warning then
+        msg = msg .. ' - ' .. 'WARNING: Error formatting log message: ' .. err
+      end
+    end
+    return msg
+  end
+end
+
+return {
+  new = buld_formatter
+}
diff --git a/rockspecs/lua-log-scm-0.rockspec b/rockspecs/lua-log-scm-0.rockspec
index ee8f3ce..194a495 100644
--- a/rockspecs/lua-log-scm-0.rockspec
+++ b/rockspecs/lua-log-scm-0.rockspec
@@ -16,6 +16,7 @@ description = {
 dependencies = {
   "lua >= 5.1",
   "date >= 2.0",
+  -- "lpeg >= 0.10.0",
   -- "llthread >= 1.2",
   -- "luasocket >= 2.0.1",
   -- "lzmq >= 0.4.2",
@@ -35,6 +36,7 @@ build = {
     ["log.formatter.concat"        ] = "lua/log/formatter/concat.lua",
     ["log.formatter.default"       ] = "lua/log/formatter/default.lua",
     ["log.formatter.format"        ] = "lua/log/formatter/format.lua",
+    ["log.formatter.pformat"       ] = "lua/log/formatter/pformat.lua",
     ["log.formatter.mix"           ] = "lua/log/formatter/mix.lua",
     ["log.logformat.default"       ] = "lua/log/logformat/default.lua",
     ["log.logformat.proxy"         ] = "lua/log/logformat/proxy.lua",
diff --git a/test/test_basic.lua b/test/test_basic.lua
index 2378d20..3d3b692 100644
--- a/test/test_basic.lua
+++ b/test/test_basic.lua
@@ -268,4 +268,75 @@ end
 
 end
 
+local _ENV = TEST_CASE'protected formatter' do
+
+function test_do_not_raise_error_nil_argument()
+  local formatter = require "log.formatter.pformat".new()
+
+  local msg
+  assert_pass(function() msg = formatter("%s", nil) end)
+  assert_string(msg)
+
+  local expected = tostring(nil)
+  assert_equal(expected, string.sub(msg,1, #expected))
+
+  assert_match('Error formatting log message', msg)
+end
+
+function test_do_not_raise_error_unknown_format()
+  local formatter = require "log.formatter.pformat".new()
+
+  local msg
+  assert_pass(function() msg = formatter("%t", 10) end)
+  assert_string(msg)
+
+  local expected = "%t"
+  assert_equal(expected, string.sub(msg,1, #expected))
+
+  assert_match('Error formatting log message', msg)
+end
+
+function test_do_not_raise_error_and_no_warning_nil_argument()
+  local formatter = require "log.formatter.pformat".new(nil, true)
+
+  local msg
+  assert_pass(function() msg = formatter("%t", nil) end)
+  assert_string(msg)
+
+  local expected = '%t'
+  assert_equal(expected, msg)
+end
+
+function test_do_not_raise_error_and_no_warning_unknown_format()
+  local formatter = require "log.formatter.pformat".new(nil, true)
+
+  local msg
+  assert_pass(function() msg = formatter("%t", 10) end)
+  assert_string(msg)
+
+  local expected = '%t'
+  assert_equal(expected, msg)
+end
+
+function test_do_not_raise_error_nil_argument_2()
+  local formatter = require "log.formatter.pformat".new(true)
+
+  local msg
+  assert_pass(function() msg = formatter("%s", nil) end)
+  assert_string(msg)
+
+  local expected = tostring(nil)
+  assert_equal(expected, string.sub(msg,1, #expected))
+
+  assert_match('Error formatting log message', msg)
+end
+
+function test_raise_error_unknown_format()
+  local formatter = require "log.formatter.pformat".new(true)
+
+  local msg = assert_error(function() msg = formatter("%t", 10) end)
+end
+
+end
+
 if not HAS_RUNNER then lunit.run() end