neovim/src/nvim/generators/gen_api_dispatch.lua

local mpack = require('mpack')

-- we need at least 4 arguments since the last two are output files
if arg[1] == '--help' then
  print('Usage: genmsgpack.lua args')
  print('Args: 1: source directory')
  print('      2: dispatch output file (dispatch_wrappers.generated.h)')
  print('      3: functions metadata output file (funcs_metadata.generated.h)')
  print('      4: API metadata output file (api_metadata.mpack)')
  print('      5: lua C bindings output file (lua_api_c_bindings.generated.c)')
  print('      rest: C files where API functions are defined')
end
assert(#arg >= 4)
local functions = {}

local nvimdir = arg[1]
package.path = nvimdir .. '/?.lua;' .. package.path

_G.vim = loadfile(nvimdir..'/../../runtime/lua/vim/shared.lua')()

local hashy = require'generators.hashy'

-- names of all headers relative to the source root (for inclusion in the
-- generated file)
local headers = {}

-- output h file with generated dispatch functions
local dispatch_outputf = arg[2]
-- output h file with packed metadata
local funcs_metadata_outputf = arg[3]
-- output metadata mpack file, for use by other build scripts
local mpack_outputf = arg[4]
local lua_c_bindings_outputf = arg[5]

-- set of function names, used to detect duplicates
local function_names = {}

local c_grammar = require('generators.c_grammar')

local function startswith(String,Start)
  return string.sub(String,1,string.len(Start))==Start
end

-- read each input file, parse and append to the api metadata
for i = 6, #arg do
  local full_path = arg[i]
  local parts = {}
  for part in string.gmatch(full_path, '[^/]+') do
    parts[#parts + 1] = part
  end
  headers[#headers + 1] = parts[#parts - 1]..'/'..parts[#parts]

  local input = io.open(full_path, 'rb')

  local tmp = c_grammar.grammar:match(input:read('*all'))
  for j = 1, #tmp do
    local fn = tmp[j]
    local public = startswith(fn.name, "nvim_") or fn.deprecated_since
    if public and not fn.noexport then
      functions[#functions + 1] = tmp[j]
      function_names[fn.name] = true
      if #fn.parameters ~= 0 and fn.parameters[1][2] == 'channel_id' then
        -- this function should receive the channel id
        fn.receives_channel_id = true
        -- remove the parameter since it won't be passed by the api client
        table.remove(fn.parameters, 1)
      end
      if #fn.parameters ~= 0 and fn.parameters[#fn.parameters][1] == 'error' then
        -- function can fail if the last parameter type is 'Error'
        fn.can_fail = true
        -- remove the error parameter, msgpack has it's own special field
        -- for specifying errors
        fn.parameters[#fn.parameters] = nil
      end
    end
  end
  input:close()
end

local function shallowcopy(orig)
  local copy = {}
  for orig_key, orig_value in pairs(orig) do
    copy[orig_key] = orig_value
  end
  return copy
end

-- Export functions under older deprecated names.
-- These will be removed eventually.
local deprecated_aliases = require("api.dispatch_deprecated")
for _,f in ipairs(shallowcopy(functions)) do
  local ismethod = false
  if startswith(f.name, "nvim_") then
    if startswith(f.name, "nvim__") then
      f.since = -1
    elseif f.since == nil then
      print("Function "..f.name.." lacks since field.\n")
      os.exit(1)
    end
    f.since = tonumber(f.since)
    if f.deprecated_since ~= nil then
      f.deprecated_since = tonumber(f.deprecated_since)
    end

    if startswith(f.name, "nvim_buf_") then
      ismethod = true
    elseif startswith(f.name, "nvim_win_") then
      ismethod = true
    elseif startswith(f.name, "nvim_tabpage_") then
      ismethod = true
    end
    f.remote = f.remote_only or not f.lua_only
    f.lua = f.lua_only or not f.remote_only
    f.eval = (not f.lua_only) and (not f.remote_only)
  else
    f.deprecated_since = tonumber(f.deprecated_since)
    assert(f.deprecated_since == 1)
    f.remote = true
    f.since = 0
  end
  f.method = ismethod
  local newname = deprecated_aliases[f.name]
  if newname ~= nil then
    if function_names[newname] then
      -- duplicate
      print("Function "..f.name.." has deprecated alias\n"
            ..newname.." which has a separate implementation.\n"..
            "Please remove it from src/nvim/api/dispatch_deprecated.lua")
      os.exit(1)
    end
    local newf = shallowcopy(f)
    newf.name = newname
    if newname == "ui_try_resize" then
      -- The return type was incorrectly set to Object in 0.1.5.
      -- Keep it that way for clients that rely on this.
      newf.return_type = "Object"
    end
    newf.impl_name = f.name
    newf.lua = false
    newf.eval = false
    newf.since = 0
    newf.deprecated_since = 1
    functions[#functions+1] = newf
  end
end

-- don't expose internal attributes like "impl_name" in public metadata
local exported_attributes = {'name', 'return_type', 'method',
                             'since', 'deprecated_since'}
local exported_functions = {}
for _,f in ipairs(functions) do
  if not startswith(f.name, "nvim__") then
    local f_exported = {}
    for _,attr in ipairs(exported_attributes) do
      f_exported[attr] = f[attr]
    end
    f_exported.parameters = {}
    for i,param in ipairs(f.parameters) do
      if param[1] == "DictionaryOf(LuaRef)" then
        param = {"Dictionary", param[2]}
      elseif startswith(param[1], "Dict(") then
        param = {"Dictionary", param[2]}
      end
      f_exported.parameters[i] = param
    end
    exported_functions[#exported_functions+1] = f_exported
  end
end


-- serialize the API metadata using msgpack and embed into the resulting
-- binary for easy querying by clients
local funcs_metadata_output = io.open(funcs_metadata_outputf, 'wb')
local packed = mpack.pack(exported_functions)
local dump_bin_array = require("generators.dump_bin_array")
dump_bin_array(funcs_metadata_output, 'funcs_metadata', packed)
funcs_metadata_output:close()

-- start building the dispatch wrapper output
local output = io.open(dispatch_outputf, 'wb')

local function real_type(type)
  local rv = type
  local rmatch = string.match(type, "Dict%(([_%w]+)%)")
  if rmatch then
    return "KeyDict_"..rmatch
  elseif c_grammar.typed_container:match(rv) then
    if rv:match('Array') then
      rv = 'Array'
    else
      rv = 'Dictionary'
    end
  end
  return rv
end

local function attr_name(rt)
  if rt == 'Float' then
    return 'floating'
  else
    return rt:lower()
  end
end

-- start the handler functions. Visit each function metadata to build the
-- handler function with code generated for validating arguments and calling to
-- the real API.
for i = 1, #functions do
  local fn = functions[i]
  if fn.impl_name == nil and fn.remote then
    local args = {}

    output:write('Object handle_'..fn.name..'(uint64_t channel_id, Array args, Error *error)')
    output:write('\n{')
    output:write('\n#if MIN_LOG_LEVEL <= LOGLVL_DBG')
    output:write('\n  logmsg(LOGLVL_DBG, "RPC: ", NULL, -1, true, "ch %" PRIu64 ": invoke '
                 ..fn.name..'", channel_id);')
    output:write('\n#endif')
    output:write('\n  Object ret = NIL;')
    -- Declare/initialize variables that will hold converted arguments
    for j = 1, #fn.parameters do
      local param = fn.parameters[j]
      local rt = real_type(param[1])
      local converted = 'arg_'..j
      output:write('\n  '..rt..' '..converted..';')
    end
    output:write('\n')
    output:write('\n  if (args.size != '..#fn.parameters..') {')
    output:write('\n    api_set_error(error, kErrorTypeException, \
      "Wrong number of arguments: expecting '..#fn.parameters..' but got %zu", args.size);')
    output:write('\n    goto cleanup;')
    output:write('\n  }\n')

    -- Validation/conversion for each argument
    for j = 1, #fn.parameters do
      local converted, param
      param = fn.parameters[j]
      converted = 'arg_'..j
      local rt = real_type(param[1])
      if rt == 'Object' then
        output:write('\n  '..converted..' = args.items['..(j - 1)..'];\n')
      elseif rt:match('^KeyDict_') then
        converted = '&' .. converted
        output:write('\n  if (args.items['..(j - 1)..'].type == kObjectTypeDictionary) {') --luacheck: ignore 631
        output:write('\n    memset('..converted..', 0, sizeof(*'..converted..'));') -- TODO: neeeee
        output:write('\n    if (!api_dict_to_keydict('..converted..', '..rt..'_get_field, args.items['..(j - 1)..'].data.dictionary, error)) {')
        output:write('\n      goto cleanup;')
        output:write('\n    }')
          output:write('\n  } else if (args.items['..(j - 1)..'].type == kObjectTypeArray && args.items['..(j - 1)..'].data.array.size == 0) {') --luacheck: ignore 631
        output:write('\n    memset('..converted..', 0, sizeof(*'..converted..'));')

        output:write('\n  } else {')
        output:write('\n    api_set_error(error, kErrorTypeException, \
          "Wrong type for argument '..j..' when calling '..fn.name..', expecting '..param[1]..'");')
        output:write('\n    goto cleanup;')
        output:write('\n  }\n')
      else
        if rt:match('^Buffer$') or rt:match('^Window$') or rt:match('^Tabpage$') then
          -- Buffer, Window, and Tabpage have a specific type, but are stored in integer
          output:write('\n  if (args.items['..
            (j - 1)..'].type == kObjectType'..rt..' && args.items['..(j - 1)..'].data.integer >= 0) {')
          output:write('\n    '..converted..' = (handle_T)args.items['..(j - 1)..'].data.integer;')
        else
          output:write('\n  if (args.items['..(j - 1)..'].type == kObjectType'..rt..') {')
          output:write('\n    '..converted..' = args.items['..(j - 1)..'].data.'..attr_name(rt)..';')
        end
        if rt:match('^Buffer$') or rt:match('^Window$') or rt:match('^Tabpage$') or rt:match('^Boolean$') then
          -- accept nonnegative integers for Booleans, Buffers, Windows and Tabpages
          output:write('\n  } else if (args.items['..
            (j - 1)..'].type == kObjectTypeInteger && args.items['..(j - 1)..'].data.integer >= 0) {')
          output:write('\n    '..converted..' = (handle_T)args.items['..(j - 1)..'].data.integer;')
        end
        if rt:match('^Float$') then
          -- accept integers for Floats
          output:write('\n  } else if (args.items['..
            (j - 1)..'].type == kObjectTypeInteger) {')
          output:write('\n    '..converted..' = (Float)args.items['..(j - 1)..'].data.integer;')
        end
        -- accept empty lua tables as empty dictionaries
        if rt:match('^Dictionary') then
          output:write('\n  } else if (args.items['..(j - 1)..'].type == kObjectTypeArray && args.items['..(j - 1)..'].data.array.size == 0) {') --luacheck: ignore 631
          output:write('\n    '..converted..' = (Dictionary)ARRAY_DICT_INIT;')
        end
        output:write('\n  } else {')
        output:write('\n    api_set_error(error, kErrorTypeException, \
          "Wrong type for argument '..j..' when calling '..fn.name..', expecting '..param[1]..'");')
        output:write('\n    goto cleanup;')
        output:write('\n  }\n')
      end
      args[#args + 1] = converted
    end

    if fn.check_textlock then
      output:write('\n  if (textlock != 0) {')
      output:write('\n    api_set_error(error, kErrorTypeException, "%s", e_secure);')
      output:write('\n    goto cleanup;')
      output:write('\n  }\n')
    end

    -- function call
    local call_args = table.concat(args, ', ')
    output:write('\n  ')
    if fn.return_type ~= 'void' then
      -- has a return value, prefix the call with a declaration
      output:write(fn.return_type..' rv = ')
    end

    -- write the function name and the opening parenthesis
    output:write(fn.name..'(')

    if fn.receives_channel_id then
      -- if the function receives the channel id, pass it as first argument
      if #args > 0 or fn.can_fail then
        output:write('channel_id, '..call_args)
      else
        output:write('channel_id')
      end
    else
      output:write(call_args)
    end

    if fn.can_fail then
      -- if the function can fail, also pass a pointer to the local error object
      if #args > 0 then
        output:write(', error);\n')
      else
        output:write('error);\n')
      end
      -- and check for the error
      output:write('\n  if (ERROR_SET(error)) {')
      output:write('\n    goto cleanup;')
      output:write('\n  }\n')
    else
      output:write(');\n')
    end

    if fn.return_type ~= 'void' then
      output:write('\n  ret = '..string.upper(real_type(fn.return_type))..'_OBJ(rv);')
    end
    output:write('\n\ncleanup:');

    output:write('\n  return ret;\n}\n\n');
  end
end

local remote_fns = {}
for _,fn in ipairs(functions) do
  if fn.remote then
    remote_fns[fn.name] = fn
  end
end
remote_fns.redraw = {impl_name="ui_client_redraw", fast=true}

local hashorder, hashfun = hashy.hashy_hash("msgpack_rpc_get_handler_for", vim.tbl_keys(remote_fns), function (idx)
  return "method_handlers["..idx.."].name"
end)

output:write("static const MsgpackRpcRequestHandler method_handlers[] = {\n")
for _, name in ipairs(hashorder) do
  local fn = remote_fns[name]
  output:write('  { .name = "'..name..'", .fn = handle_'..  (fn.impl_name or fn.name)..
               ', .fast = '..tostring(fn.fast)..'},\n')
end
output:write("};\n\n")
output:write(hashfun)

output:close()

local mpack_output = io.open(mpack_outputf, 'wb')
mpack_output:write(mpack.pack(functions))
mpack_output:close()

local function include_headers(output_handle, headers_to_include)
  for i = 1, #headers_to_include do
    if headers_to_include[i]:sub(-12) ~= '.generated.h' then
      output_handle:write('\n#include "nvim/'..headers_to_include[i]..'"')
    end
  end
end

local function write_shifted_output(_, str)
  str = str:gsub('\n  ', '\n')
  str = str:gsub('^  ', '')
  str = str:gsub(' +$', '')
  output:write(str)
end

-- start building lua output
output = io.open(lua_c_bindings_outputf, 'wb')

output:write([[
// This is an open source non-commercial project. Dear PVS-Studio, please check
// it. PVS-Studio Static Code Analyzer for C, C++ and C#: http://www.viva64.com
#include <lua.h>
#include <lualib.h>
#include <lauxlib.h>

#include "nvim/func_attr.h"
#include "nvim/api/private/defs.h"
#include "nvim/api/private/helpers.h"
#include "nvim/lua/converter.h"
#include "nvim/lua/executor.h"
]])
include_headers(output, headers)
output:write('\n')

local lua_c_functions = {}

local function process_function(fn)
  local lua_c_function_name = ('nlua_api_%s'):format(fn.name)
  write_shifted_output(output, string.format([[

  static int %s(lua_State *lstate)
  {
    Error err = ERROR_INIT;
    if (lua_gettop(lstate) != %i) {
      api_set_error(&err, kErrorTypeValidation, "Expected %i argument%s");
      goto exit_0;
    }
  ]], lua_c_function_name, #fn.parameters, #fn.parameters,
      (#fn.parameters == 1) and '' or 's'))
  lua_c_functions[#lua_c_functions + 1] = {
    binding=lua_c_function_name,
    api=fn.name
  }

  if not fn.fast then
    write_shifted_output(output, string.format([[
    if (!nlua_is_deferred_safe()) {
      return luaL_error(lstate, e_luv_api_disabled, "%s");
    }
    ]], fn.name))
  end

  if fn.check_textlock then
    write_shifted_output(output, [[
    if (textlock != 0) {
      api_set_error(&err, kErrorTypeException, "%s", e_secure);
      goto exit_0;
    }
    ]])
  end

  local cparams = ''
  local free_code = {}
  for j = #fn.parameters,1,-1 do
    local param = fn.parameters[j]
    local cparam = string.format('arg%u', j)
    local param_type = real_type(param[1])
    local lc_param_type = real_type(param[1]):lower()
    local extra = param_type == "Dictionary" and "false, " or ""
    if param[1] == "Object" or param[1] == "DictionaryOf(LuaRef)" then
      extra = "true, "
    end
    local errshift = 0
    if string.match(param_type, '^KeyDict_') then
      write_shifted_output(output, string.format([[
      %s %s = { 0 }; nlua_pop_keydict(lstate, &%s, %s_get_field, %s&err);]], param_type, cparam, cparam, param_type, extra))
      cparam = '&'..cparam
      errshift = 1 -- free incomplete dict on error
    else
      write_shifted_output(output, string.format([[
      const %s %s = nlua_pop_%s(lstate, %s&err);]], param[1], cparam, param_type, extra))
    end

    write_shifted_output(output, string.format([[

    if (ERROR_SET(&err)) {
      goto exit_%u;
    }

    ]], #fn.parameters - j + errshift))
    free_code[#free_code + 1] = ('api_free_%s(%s);'):format(
      lc_param_type, cparam)
    cparams = cparam .. ', ' .. cparams
  end
  if fn.receives_channel_id then
    cparams = 'LUA_INTERNAL_CALL, ' .. cparams
  end
  if fn.can_fail then
    cparams = cparams .. '&err'
  else
    cparams = cparams:gsub(', $', '')
  end
  local free_at_exit_code = ''
  for i = 1, #free_code do
    local rev_i = #free_code - i + 1
    local code = free_code[rev_i]
    if i == 1 and not string.match(real_type(fn.parameters[1][1]), '^KeyDict_') then
      free_at_exit_code = free_at_exit_code .. ('\n    %s'):format(code)
    else
      free_at_exit_code = free_at_exit_code .. ('\n  exit_%u:\n    %s'):format(
        rev_i, code)
    end
  end
  local err_throw_code = [[

  exit_0:
    if (ERROR_SET(&err)) {
      luaL_where(lstate, 1);
      lua_pushstring(lstate, err.msg);
      api_clear_error(&err);
      lua_concat(lstate, 2);
      return lua_error(lstate);
    }
  ]]
  local return_type
  if fn.return_type ~= 'void' then
    if fn.return_type:match('^ArrayOf') then
      return_type = 'Array'
    else
      return_type = fn.return_type
    end
    write_shifted_output(output, string.format([[
    const %s ret = %s(%s);
    nlua_push_%s(lstate, ret, true);
    api_free_%s(ret);
  %s
  %s
    return 1;
    ]], fn.return_type, fn.name, cparams, return_type, return_type:lower(),
        free_at_exit_code, err_throw_code))
  else
    write_shifted_output(output, string.format([[
    %s(%s);
  %s
  %s
    return 0;
    ]], fn.name, cparams, free_at_exit_code, err_throw_code))
  end
  write_shifted_output(output, [[
  }
  ]])
end

for _, fn in ipairs(functions) do
  if fn.lua or fn.name:sub(1, 4) == '_vim' then
    process_function(fn)
  end
end

output:write(string.format([[
void nlua_add_api_functions(lua_State *lstate);  // silence -Wmissing-prototypes
void nlua_add_api_functions(lua_State *lstate)
  FUNC_ATTR_NONNULL_ALL
{
  lua_createtable(lstate, 0, %u);
]], #lua_c_functions))
for _, func in ipairs(lua_c_functions) do
  output:write(string.format([[

  lua_pushcfunction(lstate, &%s);
  lua_setfield(lstate, -2, "%s");]], func.binding, func.api))
end
output:write([[

  lua_setfield(lstate, -2, "api");
}
]])

output:close()