neovim/scripts/msgpack-gen.lua
Thiago de Arruda 35ff53c6b0 Add msgpack_rpc_dispatch/metadata generator
This adds a lua script which parses the contents of 'api.h'. After the api is
parsed into a metadata table. After that, it will generate:

- A msgpack blob for the metadata table. This msgpack object contains everything
  scripting engines need to generate their own wrappers for the remote API.
- The `msgpack_rpc_dispatch` function, which takes care of validating msgpack
  requests, converting arguments to C types and passing control to the
  appropriate 'api.h' function. The result is then serialized back to msgpack
  and returned to the client.

This approach was used because:

- It automatically modifies `msgpack_rpc_dispatch` to reflect API changes.
- Scripting engines that generate remote call wrappers using the msgpack
  metadata will also adapt automatically to API changes
2014-04-11 14:07:45 -03:00

136 lines
3.6 KiB
Lua

lpeg = require('lpeg')
msgpack = require('cmsgpack')
P, R, S = lpeg.P, lpeg.R, lpeg.S
C, Ct, Cc, Cg = lpeg.C, lpeg.Ct, lpeg.Cc, lpeg.Cg
any = P(1) -- (consume one character)
letter = R('az', 'AZ') + S('_$')
alpha = letter + R('09')
nl = P('\n')
not_nl = any - nl
ws = S(' \t') + nl
fill = ws ^ 0
c_comment = P('//') * (not_nl ^ 0)
c_preproc = P('#') * (not_nl ^ 0)
c_id = letter * (alpha ^ 0)
c_void = P('void')
c_raw = P('char') * fill * P('*')
c_int = P('uint32_t')
c_array = c_raw * fill * P('*') * Cc('array')
c_param_type = (
(c_array * Cc('array') * fill) +
(c_raw * Cc('raw') * fill) +
(c_int * Cc('integer') * (ws ^ 1))
)
c_type = (c_void * Cc('none') * (ws ^ 1)) + c_param_type
c_param = Ct(c_param_type * C(c_id))
c_param_list = c_param * (fill * (P(',') * fill * c_param) ^ 0)
c_params = Ct(c_void + c_param_list)
c_proto = Ct(
Cg(c_type, 'rtype') * Cg(c_id, 'fname') *
fill * P('(') * fill * Cg(c_params, 'params') * fill * P(')') *
fill * P(';')
)
grammar = Ct((c_proto + c_comment + c_preproc + ws) ^ 1)
inputf = assert(arg[1])
outputf = assert(arg[2])
input = io.open(inputf, 'rb')
api = grammar:match(input:read('*all'))
input:close()
-- assign a unique integer id for each api function
for i = 1, #api do
api[i].id = i
end
output = io.open(outputf, 'wb')
output:write([[
#include <stdbool.h>
#include <stdint.h>
#include <msgpack.h>
#include "api.h"
#include "msgpack_rpc.h"
static const uint8_t msgpack_metadata[] = {
]])
packed = msgpack.pack(api)
for i = 1, #packed do
output:write(string.byte(packed, i)..', ')
if i % 10 == 0 then
output:write('\n ')
end
end
output:write([[
};
bool msgpack_rpc_dispatch(msgpack_object *req, msgpack_packer *res)
{
uint32_t method_id = (uint32_t)req->via.u64;
switch (method_id) {
case 0:
msgpack_rpc_response(req, res);
msgpack_pack_nil(res);
// The result is the `msgpack_metadata` byte array
msgpack_pack_raw(res, sizeof(msgpack_metadata));
msgpack_pack_raw_body(res, msgpack_metadata, sizeof(msgpack_metadata));
return true;
]])
for i = 1, #api do
local fn
local args = {}
fn = api[i]
output:write('\n case '..fn.id..':')
for j = 1, #fn.params do
local expected, convert, param
local idx = tostring(j - 1)
param = fn.params[j]
ref = '(req->via.array.ptr[3].via.array.ptr + '..idx..')'
-- decide which validation/conversion to use for this argument
if param[1] == 'array' then
expected = 'MSGPACK_OBJECT_ARRAY'
convert = 'msgpack_rpc_array_argument'
elseif param[1] == 'raw' then
expected = 'MSGPACK_OBJECT_RAW'
convert = 'msgpack_rpc_raw_argument'
elseif param[1] == 'integer' then
expected = 'MSGPACK_OBJECT_POSITIVE_INTEGER'
convert = 'msgpack_rpc_integer_argument'
end
output:write('\n if ('..ref..'->type != '..expected..') {')
output:write('\n return msgpack_rpc_error(req, res, "Wrong argument types");')
output:write('\n }')
table.insert(args, convert..'('..ref..')')
end
local call_args = table.concat(args, ', ')
-- convert the result back to msgpack
if fn.rtype == 'none' then
output:write('\n '..fn.fname..'('..call_args..');')
output:write('\n return msgpack_rpc_void_result(req, res);\n')
else
if fn.rtype == 'array' then
convert = 'msgpack_rpc_array_result'
elseif fn.rtype == 'raw' then
convert = 'msgpack_rpc_raw_result'
elseif fn.rtype == 'integer' then
convert = 'msgpack_rpc_integer_result'
end
output:write('\n return '..convert..'('..fn.fname..'('..call_args..'), req, res);\n')
end
end
output:write([[
default:
abort();
return false;
}
}
]])
output:close()