Merge pull request #3305 from xmake-io/json

Improve json

1 files changed, 209 insertions, 4 deletions

diff --git a/xmake/core/base/json.lua b/xmake/core/base/json.lua
index e83f6b320..4c619e69a 100644
--- a/xmake/core/base/json.lua
+++ b/xmake/core/base/json.lua
@@ -20,14 +20,219 @@
 
 -- define module: json
 local json  = json or {}
-local cjson = cjson or {}
 
 -- load modules
 local io    = require("base/io")
+local os    = require("base/os")
 local utils = require("base/utils")
 
 -- export null
-json.null = cjson.null
+if cjson then
+    json.null = cjson.null
+else
+    json.null = {}
+    setmetatable(json.null, {
+        __is_json_null = true,
+        __eq = function (obj)
+            if type(obj) == "table" then
+                local mt = getmetatable(obj)
+                if mt and mt.__is_json_null then
+                    return true
+                end
+            end
+            return false
+        end,
+        __tostring = function()
+            return "null"
+        end})
+end
+
+function json._pure_kind_of(obj)
+    if type(obj) ~= "table" then
+        return type(obj)
+    end
+    if json.is_marked_as_array(obj) then
+        return "array"
+    end
+    if obj == json.null then
+        return "nil"
+    end
+    local i = 1
+    for _ in pairs(obj) do
+        if obj[i] ~= nil then
+            i = i + 1
+        else
+            return "table"
+        end
+    end
+    if i == 1 then
+        return "table"
+    else
+        return "array"
+    end
+end
+
+function json._pure_escape_str(s)
+    local in_char  = {'\\', '"', '/', '\b', '\f', '\n', '\r', '\t'}
+    local out_char = {'\\', '"', '/',  'b',  'f',  'n',  'r',  't'}
+    for i, c in ipairs(in_char) do
+        s = s:gsub(c, '\\' .. out_char[i])
+    end
+    return s
+end
+
+function json._pure_skip_delim(str, pos, delim, err_if_missing)
+    pos = pos + #str:match('^%s*', pos)
+    if str:sub(pos, pos) ~= delim then
+        if err_if_missing then
+            os.raise("expected %s near position %d", delim, pos)
+        end
+        return pos, false
+    end
+    return pos + 1, true
+end
+
+function json._pure_parse_str_val(str, pos, val)
+    val = val or ''
+    local early_end_error = "end of input found while parsing string."
+    if pos > #str then
+        os.raise(early_end_error)
+    end
+    local c = str:sub(pos, pos)
+    if c == '"'  then
+        return val, pos + 1
+    end
+    if c ~= '\\' then
+        return json._pure_parse_str_val(str, pos + 1, val .. c)
+    end
+
+    -- we must have a \ character.
+    local esc_map = {b = '\b', f = '\f', n = '\n', r = '\r', t = '\t'}
+    local nextc = str:sub(pos + 1, pos + 1)
+    if not nextc then
+        os.raise(early_end_error)
+    end
+    return json._pure_parse_str_val(str, pos + 2, val .. (esc_map[nextc] or nextc))
+end
+
+function json._pure_parse_num_val(str, pos)
+    local num_str = str:match('^-?%d+%.?%d*[eE]?[+-]?%d*', pos)
+    local val = tonumber(num_str)
+    if not val then
+        os.raise("error parsing number at position %d", pos)
+    end
+    return val, pos + #num_str
+end
+
+function json._pure_stringify(obj, as_key)
+    local s = {}
+    local kind = json._pure_kind_of(obj)
+    if kind == "array" then
+        if as_key then
+            os.raise("can\'t encode array as key.")
+        end
+        s[#s + 1] = '['
+        for i, val in ipairs(obj) do
+            if i > 1 then s[#s + 1] = ',' end
+            s[#s + 1] = json._pure_stringify(val)
+        end
+        s[#s + 1] = ']'
+    elseif kind == "table" then
+        if as_key then
+            os.raise("can\'t encode table as key.")
+        end
+        s[#s + 1] = '{'
+        for k, v in pairs(obj) do
+            if #s > 1 then s[#s + 1] = ',' end
+            s[#s + 1] = json._pure_stringify(k, true)
+            s[#s + 1] = ':'
+            s[#s + 1] = json._pure_stringify(v)
+        end
+        s[#s + 1] = '}'
+    elseif kind == "string" then
+        return '"' .. json._pure_escape_str(obj) .. '"'
+    elseif kind == "number" then
+        if as_key then
+            return '"' .. tostring(obj) .. '"'
+        end
+        return tostring(obj)
+    elseif kind == "boolean" then
+        return tostring(obj)
+    elseif kind == "nil" then
+        return "null"
+    else
+        os.raise("unknown type: %s", kind)
+    end
+    return table.concat(s)
+end
+
+function json._pure_parse(str, pos, end_delim)
+    pos = pos or 1
+    if pos > #str then
+        os.raise("reached unexpected end of input.")
+    end
+    -- skip whitespace.
+    local pos = pos + #str:match('^%s*', pos)
+    local first = str:sub(pos, pos)
+    if first == '{' then
+        local obj, key, delim_found = {}, true, true
+        pos = pos + 1
+        while true do
+            key, pos = json._pure_parse(str, pos, '}')
+            if key == nil then
+                return obj, pos
+            end
+            if not delim_found then
+                os.raise("comma missing between object items.")
+            end
+            pos = json._pure_skip_delim(str, pos, ':', true)  -- true -> error if missing.
+            obj[key], pos = json._pure_parse(str, pos)
+            pos, delim_found = json._pure_skip_delim(str, pos, ',')
+        end
+    elseif first == '[' then
+        local arr, val, delim_found = {}, true, true
+        json.mark_as_array(arr)
+        pos = pos + 1
+        while true do
+            val, pos = json._pure_parse(str, pos, ']')
+            if val == nil then
+                return arr, pos
+            end
+            if not delim_found then
+                os.raise("comma missing between array items.")
+            end
+            arr[#arr + 1] = val
+            pos, delim_found = json._pure_skip_delim(str, pos, ',')
+        end
+    elseif first == '"' then
+        return json._pure_parse_str_val(str, pos + 1)
+    elseif first == '-' or first:match("%d") then
+        return json._pure_parse_num_val(str, pos)
+    elseif first == end_delim then
+        -- end of an object or array.
+        return nil, pos + 1
+    else
+        local literals = {["true"] = true, ["false"] = false, ["null"] = json.null}
+        for lit_str, lit_val in pairs(literals) do
+            local lit_end = pos + #lit_str - 1
+            if str:sub(pos, lit_end) == lit_str then
+                return lit_val, lit_end + 1
+            end
+        end
+        local pos_info_str = "position " .. pos .. ": " .. str:sub(pos, pos + 10)
+        os.raise("invalid json syntax starting at " .. pos_info_str)
+    end
+end
+
+-- decode json string using pure lua
+function json._pure_decode(jsonstr, opt)
+    return json._pure_parse(jsonstr)
+end
+
+-- encode json string using pua lua
+function json._pure_encode(luatable, opt)
+    return json._pure_stringify(luatable)
+end
 
 -- support empty array
 -- @see https://github.com/mpx/lua-cjson/issues/11
@@ -51,7 +256,7 @@ end
 -- @return              the lua table
 --
 function json.decode(jsonstr, opt)
-    local ok, luatable_or_errors = utils.trycall(cjson.decode, nil, jsonstr)
+    local ok, luatable_or_errors = utils.trycall(cjson and cjson.decode or json._pure_decode, nil, jsonstr)
     if not ok then
         return nil, string.format("decode json failed, %s", luatable_or_errors)
     end
@@ -66,7 +271,7 @@ end
 -- @return              the json string
 --
 function json.encode(luatable, opt)
-    local ok, jsonstr_or_errors = utils.trycall(cjson.encode, nil, luatable)
+    local ok, jsonstr_or_errors = utils.trycall(cjson and cjson.encode or json._pure_encode, nil, luatable)
     if not ok then
         return nil, string.format("encode json failed, %s", jsonstr_or_errors)
     end