[grilo-plugins] lua-factory: Add inspect.lua helper

[Victor Toso de Carvalho <victortoso src gnome org>]

commit 048ad86e6ee1763d799a6f3dff8e6f65884b3006
Author: Bastien Nocera <hadess hadess net>
Date:   Mon Jun 15 11:49:59 2015 +0200

    lua-factory: Add inspect.lua helper
    
    Which is very useful when developing new sources, to inspect the results
    of json parsing, etc.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=750983

 src/lua-factory/Makefile.am                   |   23 ++-
 src/lua-factory/grl-lua-factory.gresource.xml |    6 +
 src/lua-factory/grl-lua-library.c             |   43 ++++
 src/lua-factory/grl-lua-library.h             |    1 +
 src/lua-factory/lua-library/inspect.lua       |  328 +++++++++++++++++++++++++
 src/lua-factory/lua-library/lua-libraries.h   |    4 +
 6 files changed, 404 insertions(+), 1 deletions(-)
---
diff --git a/src/lua-factory/Makefile.am b/src/lua-factory/Makefile.am
index 33ae125..d4810d9 100644
--- a/src/lua-factory/Makefile.am
+++ b/src/lua-factory/Makefile.am
@@ -31,6 +31,8 @@ libgrlluafactory_la_SOURCES =                                 \
        grl-lua-library.c                                       \
        grl-lua-library.h                                       \
        grl-lua-common.h                                        \
+       luafactoryresources.c                                   \
+       luafactoryresources.h                                   \
        lua-library/htmlentity.c                                \
        lua-library/htmlentity.h                                \
        lua-library/lua-json.c                                  \
@@ -40,13 +42,32 @@ extdir                      = $(GRL_PLUGINS_DIR)
 luafactoryxmldir       = $(GRL_PLUGINS_DIR)
 luafactoryxml_DATA     = $(LUA_FACTORY_PLUGIN_ID).xml
 
+lua_factory_resources_files =  \
+  lua-library/inspect.lua
+
+luafactoryresources.c: grl-lua-factory.gresource.xml luafactoryresources.h $(lua_factory_resources_files)
+       $(AM_V_GEN) $(GLIB_COMPILE_RESOURCES) $(srcdir)/grl-lua-factory.gresource.xml \
+               --target=$@ --sourcedir=$(srcdir) --c-name _grl_lua_factory --generate-source
+
+luafactoryresources.h: grl-lua-factory.gresource.xml
+       $(AM_V_GEN) $(GLIB_COMPILE_RESOURCES) $(srcdir)/grl-lua-factory.gresource.xml \
+               --target=$@ --sourcedir=$(srcdir) --c-name _grl_lua_factory --generate-header
+
 # Rules to enable tests
 copy-xml-to-libs-dir: libgrlluafactory.la
        cp -f $(srcdir)/$(luafactoryxml_DATA) $(builddir)/.libs/
 
 all-local: copy-xml-to-libs-dir
 
-EXTRA_DIST += $(luafactoryxml_DATA) lua-library/htmlentity.gperf
+CLEANFILES =                           \
+       luafactoryresources.h           \
+       luafactoryresources.c
+
+EXTRA_DIST +=                                  \
+       $(luafactoryxml_DATA)                   \
+       $(lua_factory_resources_files)          \
+       grl-lua-factory.gresource.xml           \
+       lua-library/htmlentity.gperf
 
 DIST_SUBDIRS = sources
 
diff --git a/src/lua-factory/grl-lua-factory.gresource.xml b/src/lua-factory/grl-lua-factory.gresource.xml
new file mode 100644
index 0000000..0e98958
--- /dev/null
+++ b/src/lua-factory/grl-lua-factory.gresource.xml
@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<gresources>
+  <gresource prefix="/org/gnome/grilo/plugins/lua-factory">
+    <file compressed="false">lua-library/inspect.lua</file>
+  </gresource>
+</gresources>
diff --git a/src/lua-factory/grl-lua-library.c b/src/lua-factory/grl-lua-library.c
index ef3deae..10c253a 100644
--- a/src/lua-factory/grl-lua-library.c
+++ b/src/lua-factory/grl-lua-library.c
@@ -1194,6 +1194,32 @@ grl_l_unzip (lua_State *L)
 
 /* ================== Lua-Library initialization =========================== */
 
+/** Load library included as GResource and run it with lua_pcall.
+  * Caller should handle the stack aftwards.
+ **/
+static gboolean
+load_gresource_library (lua_State   *L,
+                        const gchar *uri)
+{
+  GFile *file;
+  gchar *data;
+  gsize size;
+  GError *error = NULL;
+  gboolean ret = TRUE;
+
+  file = g_file_new_for_uri (uri);
+  g_file_load_contents (file, NULL, &data, &size, NULL, &error);
+  g_assert_no_error (error);
+  g_clear_pointer (&file, g_object_unref);
+
+  if (luaL_dostring (L, data)) {
+    GRL_WARNING ("Failed to load %s due %s", uri, lua_tostring (L, -1));
+    ret = FALSE;
+  }
+  g_free (data);
+  return ret;
+}
+
 gint
 luaopen_grilo (lua_State *L)
 {
@@ -1225,6 +1251,23 @@ luaopen_grilo (lua_State *L)
   luaopen_json (L);
   lua_settable (L, -3);
 
+  /* Load inspect.lua and save object in global environment table */
+  lua_getglobal (L, LUA_ENV_TABLE);
+  if (load_gresource_library (L, URI_LUA_LIBRARY_INSPECT) &&
+      lua_istable (L, -1)) {
+      /* Top of the stack is inspect table from inspect.lua */
+      lua_getfield (L, -1, "inspect");
+      /* Top of the stack is inspect.inspect */
+      lua_setfield (L, -4, GRILO_LUA_LIBRARY_INSPECT);
+      /* grl.lua.inspect points to inspect.inspect */
+
+      /* Save inspect table in LUA_ENV_TABLE */
+      lua_setfield (L, -2, GRILO_LUA_INSPECT_INDEX);
+  } else {
+      GRL_WARNING ("Failed to load inspect.lua");
+  }
+  lua_pop (L, 1);
+
   /* Those modules are called in 'lua' table, inside 'grl' */
   lua_settable (L, -3);
   return 1;
diff --git a/src/lua-factory/grl-lua-library.h b/src/lua-factory/grl-lua-library.h
index b678f58..c9885c6 100644
--- a/src/lua-factory/grl-lua-library.h
+++ b/src/lua-factory/grl-lua-library.h
@@ -35,6 +35,7 @@
 #define LUA_ENV_TABLE "_G"
 
 #define GRILO_LUA_OPERATION_INDEX "grl-lua-operation-spec"
+#define GRILO_LUA_INSPECT_INDEX   "grl-lua-data-inspect"
 
 gint luaopen_grilo (lua_State *L);
 
diff --git a/src/lua-factory/lua-library/inspect.lua b/src/lua-factory/lua-library/inspect.lua
new file mode 100644
index 0000000..b7107d4
--- /dev/null
+++ b/src/lua-factory/lua-library/inspect.lua
@@ -0,0 +1,328 @@
+local inspect ={
+  _VERSION = 'inspect.lua 3.0.0',
+  _URL     = 'http://github.com/kikito/inspect.lua',
+  _DESCRIPTION = 'human-readable representations of tables',
+  _LICENSE = [[
+    MIT LICENSE
+
+    Copyright (c) 2013 Enrique García Cota
+
+    Permission is hereby granted, free of charge, to any person obtaining a
+    copy of this software and associated documentation files (the
+    "Software"), to deal in the Software without restriction, including
+    without limitation the rights to use, copy, modify, merge, publish,
+    distribute, sublicense, and/or sell copies of the Software, and to
+    permit persons to whom the Software is furnished to do so, subject to
+    the following conditions:
+
+    The above copyright notice and this permission notice shall be included
+    in all copies or substantial portions of the Software.
+
+    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+    OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+    MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+    IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+    CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+    TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+    SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+  ]]
+}
+
+inspect.KEY       = setmetatable({}, {__tostring = function() return 'inspect.KEY' end})
+inspect.METATABLE = setmetatable({}, {__tostring = function() return 'inspect.METATABLE' end})
+
+-- Apostrophizes the string if it has quotes, but not aphostrophes
+-- Otherwise, it returns a regular quoted string
+local function smartQuote(str)
+  if str:match('"') and not str:match("'") then
+    return "'" .. str .. "'"
+  end
+  return '"' .. str:gsub('"', '\\"') .. '"'
+end
+
+local controlCharsTranslation = {
+  ["\a"] = "\\a",  ["\b"] = "\\b", ["\f"] = "\\f",  ["\n"] = "\\n",
+  ["\r"] = "\\r",  ["\t"] = "\\t", ["\v"] = "\\v"
+}
+
+local function escape(str)
+  local result = str:gsub("\\", "\\\\"):gsub("(%c)", controlCharsTranslation)
+  return result
+end
+
+local function isIdentifier(str)
+  return type(str) == 'string' and str:match( "^[_%a][_%a%d]*$" )
+end
+
+local function isSequenceKey(k, length)
+  return type(k) == 'number'
+     and 1 <= k
+     and k <= length
+     and math.floor(k) == k
+end
+
+local defaultTypeOrders = {
+  ['number']   = 1, ['boolean']  = 2, ['string'] = 3, ['table'] = 4,
+  ['function'] = 5, ['userdata'] = 6, ['thread'] = 7
+}
+
+local function sortKeys(a, b)
+  local ta, tb = type(a), type(b)
+
+  -- strings and numbers are sorted numerically/alphabetically
+  if ta == tb and (ta == 'string' or ta == 'number') then return a < b end
+
+  local dta, dtb = defaultTypeOrders[ta], defaultTypeOrders[tb]
+  -- Two default types are compared according to the defaultTypeOrders table
+  if dta and dtb then return defaultTypeOrders[ta] < defaultTypeOrders[tb]
+  elseif dta     then return true  -- default types before custom ones
+  elseif dtb     then return false -- custom types after default ones
+  end
+
+  -- custom types are sorted out alphabetically
+  return ta < tb
+end
+
+local function getNonSequentialKeys(t)
+  local keys, length = {}, #t
+  for k,_ in pairs(t) do
+    if not isSequenceKey(k, length) then table.insert(keys, k) end
+  end
+  table.sort(keys, sortKeys)
+  return keys
+end
+
+local function getToStringResultSafely(t, mt)
+  local __tostring = type(mt) == 'table' and rawget(mt, '__tostring')
+  local str, ok
+  if type(__tostring) == 'function' then
+    ok, str = pcall(__tostring, t)
+    str = ok and str or 'error: ' .. tostring(str)
+  end
+  if type(str) == 'string' and #str > 0 then return str end
+end
+
+local maxIdsMetaTable = {
+  __index = function(self, typeName)
+    rawset(self, typeName, 0)
+    return 0
+  end
+}
+
+local idsMetaTable = {
+  __index = function (self, typeName)
+    local col = setmetatable({}, {__mode = "kv"})
+    rawset(self, typeName, col)
+    return col
+  end
+}
+
+local function countTableAppearances(t, tableAppearances)
+  tableAppearances = tableAppearances or setmetatable({}, {__mode = "k"})
+
+  if type(t) == 'table' then
+    if not tableAppearances[t] then
+      tableAppearances[t] = 1
+      for k,v in pairs(t) do
+        countTableAppearances(k, tableAppearances)
+        countTableAppearances(v, tableAppearances)
+      end
+      countTableAppearances(getmetatable(t), tableAppearances)
+    else
+      tableAppearances[t] = tableAppearances[t] + 1
+    end
+  end
+
+  return tableAppearances
+end
+
+local copySequence = function(s)
+  local copy, len = {}, #s
+  for i=1, len do copy[i] = s[i] end
+  return copy, len
+end
+
+local function makePath(path, ...)
+  local keys = {...}
+  local newPath, len = copySequence(path)
+  for i=1, #keys do
+    newPath[len + i] = keys[i]
+  end
+  return newPath
+end
+
+local function processRecursive(process, item, path)
+  if item == nil then return nil end
+
+  local processed = process(item, path)
+  if type(processed) == 'table' then
+    local processedCopy = {}
+    local processedKey
+
+    for k,v in pairs(processed) do
+      processedKey = processRecursive(process, k, makePath(path, k, inspect.KEY))
+      if processedKey ~= nil then
+        processedCopy[processedKey] = processRecursive(process, v, makePath(path, processedKey))
+      end
+    end
+
+    local mt  = processRecursive(process, getmetatable(processed), makePath(path, inspect.METATABLE))
+    setmetatable(processedCopy, mt)
+    processed = processedCopy
+  end
+  return processed
+end
+
+
+-------------------------------------------------------------------
+
+local Inspector = {}
+local Inspector_mt = {__index = Inspector}
+
+function Inspector:puts(...)
+  local args   = {...}
+  local buffer = self.buffer
+  local len    = #buffer
+  for i=1, #args do
+    len = len + 1
+    buffer[len] = tostring(args[i])
+  end
+end
+
+function Inspector:down(f)
+  self.level = self.level + 1
+  f()
+  self.level = self.level - 1
+end
+
+function Inspector:tabify()
+  self:puts(self.newline, string.rep(self.indent, self.level))
+end
+
+function Inspector:alreadyVisited(v)
+  return self.ids[type(v)][v] ~= nil
+end
+
+function Inspector:getId(v)
+  local tv = type(v)
+  local id = self.ids[tv][v]
+  if not id then
+    id              = self.maxIds[tv] + 1
+    self.maxIds[tv] = id
+    self.ids[tv][v] = id
+  end
+  return id
+end
+
+function Inspector:putKey(k)
+  if isIdentifier(k) then return self:puts(k) end
+  self:puts("[")
+  self:putValue(k)
+  self:puts("]")
+end
+
+function Inspector:putTable(t)
+  if t == inspect.KEY or t == inspect.METATABLE then
+    self:puts(tostring(t))
+  elseif self:alreadyVisited(t) then
+    self:puts('<table ', self:getId(t), '>')
+  elseif self.level >= self.depth then
+    self:puts('{...}')
+  else
+    if self.tableAppearances[t] > 1 then self:puts('<', self:getId(t), '>') end
+
+    local nonSequentialKeys = getNonSequentialKeys(t)
+    local length            = #t
+    local mt                = getmetatable(t)
+    local toStringResult    = getToStringResultSafely(t, mt)
+
+    self:puts('{')
+    self:down(function()
+      if toStringResult then
+        self:puts(' -- ', escape(toStringResult))
+        if length >= 1 then self:tabify() end
+      end
+
+      local count = 0
+      for i=1, length do
+        if count > 0 then self:puts(',') end
+        self:puts(' ')
+        self:putValue(t[i])
+        count = count + 1
+      end
+
+      for _,k in ipairs(nonSequentialKeys) do
+        if count > 0 then self:puts(',') end
+        self:tabify()
+        self:putKey(k)
+        self:puts(' = ')
+        self:putValue(t[k])
+        count = count + 1
+      end
+
+      if mt then
+        if count > 0 then self:puts(',') end
+        self:tabify()
+        self:puts('<metatable> = ')
+        self:putValue(mt)
+      end
+    end)
+
+    if #nonSequentialKeys > 0 or mt then -- result is multi-lined. Justify closing }
+      self:tabify()
+    elseif length > 0 then -- array tables have one extra space before closing }
+      self:puts(' ')
+    end
+
+    self:puts('}')
+  end
+end
+
+function Inspector:putValue(v)
+  local tv = type(v)
+
+  if tv == 'string' then
+    self:puts(smartQuote(escape(v)))
+  elseif tv == 'number' or tv == 'boolean' or tv == 'nil' then
+    self:puts(tostring(v))
+  elseif tv == 'table' then
+    self:putTable(v)
+  else
+    self:puts('<',tv,' ',self:getId(v),'>')
+  end
+end
+
+-------------------------------------------------------------------
+
+function inspect.inspect(root, options)
+  options       = options or {}
+
+  local depth   = options.depth   or math.huge
+  local newline = options.newline or '\n'
+  local indent  = options.indent  or '  '
+  local process = options.process
+
+  if process then
+    root = processRecursive(process, root, {})
+  end
+
+  local inspector = setmetatable({
+    depth            = depth,
+    buffer           = {},
+    level            = 0,
+    ids              = setmetatable({}, idsMetaTable),
+    maxIds           = setmetatable({}, maxIdsMetaTable),
+    newline          = newline,
+    indent           = indent,
+    tableAppearances = countTableAppearances(root)
+  }, Inspector_mt)
+
+  inspector:putValue(root)
+
+  return table.concat(inspector.buffer)
+end
+
+setmetatable(inspect, { __call = function(_, ...) return inspect.inspect(...) end })
+
+return inspect
+
diff --git a/src/lua-factory/lua-library/lua-libraries.h b/src/lua-factory/lua-library/lua-libraries.h
index 6905915..3af5f55 100644
--- a/src/lua-factory/lua-library/lua-libraries.h
+++ b/src/lua-factory/lua-library/lua-libraries.h
@@ -29,6 +29,10 @@
 #ifndef _GRL_LUA_LIBRARY_JSON_H_
 #define _GRL_LUA_LIBRARY_JSON_H_
 
+#define GRESOURCE_LIBRARY_PREFIX    "resource:///org/gnome/grilo/plugins/lua-factory/lua-library/"
+#define URI_LUA_LIBRARY_INSPECT     GRESOURCE_LIBRARY_PREFIX "inspect.lua"
+
+#define GRILO_LUA_LIBRARY_INSPECT   "inspect"
 #define GRILO_LUA_LIBRARY_JSON  "json"
 
 gint luaopen_json (lua_State *L);