├── .gitignore ├── LICENSE ├── README.md ├── rebar.config ├── relx.config └── src ├── niffy.app.src ├── niffy.erl └── niffy_transform.erl /.gitignore: -------------------------------------------------------------------------------- 1 | .rebar3 2 | _* 3 | .eunit 4 | deps 5 | *.o 6 | *.beam 7 | *.plt 8 | *.swp 9 | *.swo 10 | .erlang.cookie 11 | ebin 12 | log 13 | erl_crash.dump 14 | rel/example_project 15 | .concrete/DEV_MODE 16 | .rebar 17 | logs 18 | _build 19 | _checkouts 20 | .DS_Store 21 | .idea -------------------------------------------------------------------------------- /LICENSE: -------------------------------------------------------------------------------- 1 | Apache License 2 | Version 2.0, January 2004 3 | http://www.apache.org/licenses/ 4 | 5 | TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION 6 | 7 | 1. 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The text should be enclosed in the appropriate 184 | comment syntax for the file format. We also recommend that a 185 | file or class name and description of purpose be included on the 186 | same "printed page" as the copyright notice for easier 187 | identification within third-party archives. 188 | 189 | Copyright 2016 Erlang Solutions Ltd. 190 | 191 | Licensed under the Apache License, Version 2.0 (the "License"); 192 | you may not use this file except in compliance with the License. 193 | You may obtain a copy of the License at 194 | 195 | http://www.apache.org/licenses/LICENSE-2.0 196 | 197 | Unless required by applicable law or agreed to in writing, software 198 | distributed under the License is distributed on an "AS IS" BASIS, 199 | WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 200 | See the License for the specific language governing permissions and 201 | limitations under the License. 202 | -------------------------------------------------------------------------------- /README.md: -------------------------------------------------------------------------------- 1 | # niffy 2 | Erlang parse transform to generate NIF files from inlined C code. 3 | 4 | ### Why? 5 | Writing NIFs is time consuming and their code can't help but being riddled with macros. And not only that; our C code has to be in a separate file, adding a layer of complexity when debugging and trying to figure out exactly what's going on. 6 | 7 | ### What can niffy do to help? 8 | Simple, instead of writing your nifs, just inline some C code in your erlang files: 9 | 10 | ```erlang 11 | -module(example). 12 | -niffy([square/1]). 13 | -export([square/1]). 14 | 15 | square(_A) -> 16 | "int square(int a) 17 | { 18 | return a * a; 19 | }". 20 | ``` 21 | 22 | That code compiles and does exactly what you would expect: 23 | 24 | ```erlang 25 | > example:square(2). 26 | 4 27 | ``` 28 | 29 | ### How? 30 | 31 | 32 | 33 | ### But seriously, how? 34 | 35 | Niffy takes care of many things. First, it generates the NIF from the inlined C code, making all the changes so that erlang can include it. For example, given the previous erlang file, niffy will generate (and compile) the following C code: 36 | 37 | ```c 38 | #include "erl_nif.h" 39 | 40 | static ERL_NIF_TERM square_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]) 41 | { 42 | int a; 43 | if (!enif_get_int(env, argv[0], &a)) 44 | return enif_make_badarg(env); 45 | return enif_make_int(env, a * a); 46 | } 47 | 48 | static ErlNifFunc niffuncs[] = {{"square", 1, square_nif, 0}}; 49 | 50 | ERL_NIF_INIT(example, niffuncs, NULL, NULL, NULL, NULL) 51 | ``` 52 | 53 | (Yes, it also handles the indentation) 54 | 55 | Once that's done, it will modify the original erlang file so that the function ``square/1`` throws ``nif_not_loaded`` if you attempt to call it. 56 | 57 | And finally, it will add a function to load the nif on the module's ``on_load`` function (don't worry, if no ``on_load`` function is present on the module, niffy just adds one). 58 | 59 | ### What else? 60 | Well, that was just a basic example, niffy also handles includes, whatever compiler flags you need and you can even flag some functions as dirty. 61 | 62 | A more complex example would be this one, where instead of a list of functions we define a map with some properties (they are actually all optional): 63 | 64 | ```erlang 65 | -module(another_example). 66 | 67 | -niffy(#{functions => [sum_c/2, square/1, {nat_log/1, cpu_bound}], 68 | options => [{flags, ["-pedantic"]}]}). 69 | 70 | -export([sum/2, square/1, nat_log/1]). 71 | 72 | square(_A) -> 73 | "int square(int a) 74 | { 75 | return a * a; 76 | }". 77 | 78 | nat_log(_A) -> 79 | "#include 80 | double nat_log(double a) 81 | { 82 | // this will return the natural log 83 | double logA = log(a); 84 | // return logB; 85 | return logA; 86 | }". 87 | ``` 88 | 89 | As you can see, it's pretty clear when one of our functions is either ``cpu_bound`` or ``io_bound``. Also, including headers and setting compiler flags is pretty simple (also, notice that you can add the headers as many times as you wish, including on the function bodies, just use whatever you feel makes for a more readable file). 90 | 91 | Again, that works just fine and generates pretty easy to follow code: 92 | 93 | ```c 94 | #include "erl_nif.h" 95 | #include 96 | 97 | static ERL_NIF_TERM nat_log_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]) 98 | { 99 | double a; 100 | if (!enif_get_double(env, argv[0], &a)) 101 | return enif_make_badarg(env); 102 | // this will return the natural log 103 | double logA = log(a); 104 | // return enif_make_double(env, logB); 105 | return logA; 106 | } 107 | 108 | static ERL_NIF_TERM square_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]) 109 | { 110 | int a; 111 | if (!enif_get_int(env, argv[0], &a)) 112 | return enif_make_badarg(env); 113 | return enif_make_int(env, a * a); 114 | } 115 | 116 | static ErlNifFunc niffuncs[] = {{"nat_log", 1, nat_log_nif, ERL_NIF_DIRTY_JOB_CPU_BOUND}, 117 | {"square", 1, square_nif, 0}}; 118 | 119 | ERL_NIF_INIT(another_example, niffuncs, NULL, NULL, NULL, NULL) 120 | ``` 121 | 122 | Just remember that niffy is not parsing your code. And it's just making some reasonable assumptions regarding how it is written. You can see that in the way it handled the C comments, any ``return .*;`` that's not followed by ``enif_make_*`` will be modified. 123 | 124 | ### How to use niffy? 125 | Couldn't be simpler: Set it as a dependency of your project and add ``{parse_transform, niffy_transform}`` to ``erl_opts`` in your ``rebar.config`` file. Any other options go into ``niffy_options`` on ``erl_opts``: The compiler flags that apply to all the files, and the directory where you want to output the generated C code: 126 | 127 | ```erlang 128 | %{application, your_app_name_here}, 129 | {niffy_options, [{compiler, "gcc"}, % Default 130 | {flags, ["-Werror", 131 | "-I/usr/lib/erlang/erts-5.8.1/include"]}, 132 | {c_dir, "_generated/c_src"}, % Default 133 | {strict_types, false}]} 134 | ``` 135 | 136 | Also, you can tell **niffy** the name of your application. This is only useful if you are writing a dependency. 137 | 138 | Just keep in mind that if you want to upgrade niffy, you **should delete your _build folder** (otherwise rebar3 doesn't realise it needs to rebuild all the files) and that it would be a good idea to add ``*.so`` and ``_generated`` to your ``.gitignore``. 139 | 140 | ### Contact Us 141 | For **questions** or **general comments** regarding the use of this library, please use our public 142 | [hipchat room](https://www.hipchat.com/gpBpW3SsT). 143 | 144 | If you find any **bugs**, **problems** or got any **suggestions**, please [open an issue](https://github.com/inaka/niffy/issues/new) in this repo (or even a pull request :)). 145 | 146 | And you can check all of our open-source projects at [inaka.github.io](http://inaka.github.io) 147 | -------------------------------------------------------------------------------- /rebar.config: -------------------------------------------------------------------------------- 1 | {erl_opts, [debug_info]}. 2 | {deps, []}. 3 | {ct_compile_opts, [ warn_unused_vars 4 | , warn_export_all 5 | , warn_shadow_vars 6 | , warn_unused_import 7 | , warn_unused_function 8 | , warn_bif_clash 9 | , warn_unused_record 10 | , warn_deprecated_function 11 | , warn_obsolete_guard 12 | , strict_validation 13 | , warn_export_vars 14 | , warn_exported_vars 15 | , warn_missing_spec 16 | , warn_untyped_record 17 | , debug_info 18 | ]}. 19 | -------------------------------------------------------------------------------- /relx.config: -------------------------------------------------------------------------------- 1 | {release, {niffy, "0.1.0"}, [kernel, stdlib]}. 2 | %{sys_config, "config/sys.config"}. 3 | {extended_start_script, true}. -------------------------------------------------------------------------------- /src/niffy.app.src: -------------------------------------------------------------------------------- 1 | {application, 2 | niffy, 3 | [{description, "NIF code generation tool"}, 4 | {vsn, "0.1.0"}, 5 | {id, "niffy"}, 6 | {registered, []}, 7 | {modules, []}, 8 | {applications, []}, 9 | {env, []}, 10 | {maintainers, ["Inaka", "HernanRivasAcosta"]}, 11 | {licenses, ["Apache2"]}]}. 12 | -------------------------------------------------------------------------------- /src/niffy.erl: -------------------------------------------------------------------------------- 1 | -module(niffy). 2 | -export([nif_filename/2]). 3 | 4 | %%============================================================================== 5 | %% API 6 | %%============================================================================== 7 | nif_filename(AppName, NIF) -> 8 | Dir = case code:priv_dir(AppName) of 9 | {error, bad_name} -> 10 | case filelib:is_dir(filename:join("..", "priv")) of 11 | true -> 12 | filename:join("..", "priv"); 13 | _ -> 14 | "priv" 15 | end; 16 | PrivDir -> 17 | PrivDir 18 | end, 19 | filename:join(Dir, NIF). -------------------------------------------------------------------------------- /src/niffy_transform.erl: -------------------------------------------------------------------------------- 1 | -module(niffy_transform). 2 | -export([parse_transform/2]). 3 | 4 | %%============================================================================== 5 | %% API 6 | %%============================================================================== 7 | parse_transform(Forms, Options) -> 8 | case config(Forms) of 9 | undefined -> 10 | Forms; 11 | Config -> 12 | % Get the functions to niffify 13 | Functions = maps:get(functions, Config, []), 14 | % Get the configuration 15 | NiffyOptions = options(maps:get(options, Config, []), 16 | proplists:get_value(niffy_options, Options, [])), 17 | Module = module(Forms), 18 | NIFId = nif_id(Module), 19 | {ok, AppDir} = file:get_cwd(), 20 | 21 | % Parse the Forms and get the C code 22 | {CFunctions, Forms2} = functions_from_forms(Functions, Forms), 23 | 24 | % Build the C file 25 | CDir = proplists:get_value(c_dir, NiffyOptions), 26 | CFileName = filename:join([AppDir, CDir, NIFId ++ ".c"]), 27 | CCode = build_c_code(Module, lists:reverse(CFunctions), NiffyOptions), 28 | ok = filelib:ensure_dir(CFileName), 29 | ok = file:write_file(CFileName, CCode), 30 | 31 | % Make sure we have an init function where we can add the nif loading code 32 | {InitFunc, Forms3} = ensure_init_function(Module, Forms2), 33 | 34 | % Compile the C file to the priv folder 35 | SOName = filename:join([AppDir, "priv", NIFId ++ ".so"]), 36 | ok = filelib:ensure_dir(SOName), 37 | Flags = flags(NiffyOptions), 38 | Compiler = proplists:get_value(compiler, NiffyOptions), 39 | ExtraFiles = proplists:get_value(extra_files, NiffyOptions), 40 | FilesToCompile = string:join([CFileName | ExtraFiles], " "), 41 | Command = [Compiler, " -o ", SOName, " ", Flags, " ", FilesToCompile], 42 | _ = case os:cmd(Command) of 43 | [] -> 44 | ignore; 45 | Error -> 46 | io:format("Compiler Error:~n$ ~s~n> ~s", [Command, Error]) 47 | end, 48 | % Add the call to load the nif 49 | add_nif_loader(Forms3, InitFunc, {app_name(Options, AppDir), NIFId}) 50 | end. 51 | 52 | %%============================================================================== 53 | %% Utils 54 | %%============================================================================== 55 | config([]) -> 56 | undefined; 57 | % There is the full map configuration for niffy 58 | config([{attribute, _, niffy, Config} | _]) when is_map(Config) -> 59 | Config#{functions := normalize_functions(maps:get(functions, Config))}; 60 | % And also a simple function list, in this case, we need to build the map 61 | config([{attribute, _, niffy, Functions} | _]) when is_list(Functions) -> 62 | #{functions => normalize_functions(Functions)}; 63 | config([_ | T]) -> 64 | config(T). 65 | 66 | % Make sure all the function specifications have the optional DirtyMode value 67 | normalize_functions(Functions) -> 68 | normalize_functions(Functions, []). 69 | 70 | normalize_functions([], Acc) -> 71 | Acc; 72 | normalize_functions([{{F, A}, DirtyMode} | T], Acc) -> 73 | normalize_functions(T, [{F, A, DirtyMode} | Acc]); 74 | normalize_functions([{F, A} | T], Acc) -> 75 | normalize_functions(T, [{F, A, none} | Acc]). 76 | 77 | options(ModuleOpts, GlobalOpts) -> 78 | [get_option(Type, Name, ModuleOpts, GlobalOpts, Default) || 79 | {Name, Type, Default} <- options_spec()]. 80 | 81 | % This is easy to read, the options are simply tuples where the first element is 82 | % the name, the second is the mode, and the third is the default value. 83 | % Available modes are: 84 | % - merge: Appends the module configuration to the erl_opts AND the default 85 | % - module_first: It will use the module value if available, if not, it will use 86 | % the one in erl_opts (and the default as a last resort) 87 | % - global_only: Used when it makes no sense to have the option on a module 88 | % - module_only: And this is the counterpart, sometimes it doesn't make sense to 89 | % have a global setting 90 | options_spec() -> 91 | [{flags, merge, ["-fpic", "-shared"]}, 92 | {compiler, module_first, "gcc"}, 93 | {includes, module_only, []}, 94 | {strict_types, module_first, true}, 95 | {c_dir, global_only, "_generated/c_src"}, 96 | {on_load, module_only, "NULL"}, 97 | {on_upgrade, module_only, "NULL"}, 98 | {on_unload, module_only, "NULL"}, 99 | {extra_files, merge, []}, 100 | {default_string_type, module_first, string}, 101 | {max_string_size, module_first, 1023}, 102 | {string_encoding, module_first, "ERL_NIF_LATIN1"}]. 103 | 104 | get_option(merge, K, ModuleOpts, GlobalOpts, Def) -> 105 | {K, proplists:get_value(K, ModuleOpts, []) ++ 106 | proplists:get_value(K, GlobalOpts, []) ++ 107 | Def}; 108 | get_option(module_only, K, ModuleOpts, _GlobalOpts, Def) -> 109 | {K, proplists:get_value(K, ModuleOpts, Def)}; 110 | get_option(global_only, K, _ModuleOpts, GlobalOpts, Def) -> 111 | {K, proplists:get_value(K, GlobalOpts, Def)}; 112 | get_option(module_first, K, ModuleOpts, GlobalOpts, Def) -> 113 | {K, 114 | proplists:get_value(K, ModuleOpts, proplists:get_value(K, GlobalOpts, Def))}. 115 | 116 | % Retrieve the module name 117 | module([{attribute, _, module, Module} | _]) -> 118 | Module; 119 | module([_ | T]) -> 120 | module(T). 121 | 122 | % Get the C code of each of the functions on the niffy config 123 | functions_from_forms(Functions, Forms) -> 124 | functions_from_forms(Functions, Forms, [], []). 125 | 126 | functions_from_forms([], Forms, Functions, Acc) -> 127 | {Functions, lists:reverse(Acc, Forms)}; 128 | functions_from_forms(_, [], Functions, Acc) -> 129 | {Functions, lists:reverse(Acc)}; 130 | functions_from_forms(FunctionNames, 131 | [{function, L1, F, A, 132 | [{clause, _, Args, [], [{string, L2, CCode}]}]} = H | T], 133 | Functions, Acc) -> 134 | case take_function(F, A, FunctionNames) of 135 | false -> 136 | functions_from_forms(FunctionNames, T, Functions, [H | Acc]); 137 | {{F, A, DirtyMode}, NewFunctionNames} -> 138 | Stub = get_function_stub(L1, L2, F, A, Args), 139 | NewFunctions = [{F, A, DirtyMode, CCode} | Functions], 140 | functions_from_forms(NewFunctionNames, T, NewFunctions, [Stub | Acc]) 141 | end; 142 | functions_from_forms(FunctionNames, [H | T], Functions, Acc) -> 143 | functions_from_forms(FunctionNames, T, Functions, [H | Acc]). 144 | 145 | % Get the function specification from the function list 146 | take_function(F, A, Functions) -> 147 | take_function(F, A, Functions, []). 148 | 149 | take_function(_F, _A, [], _Acc) -> 150 | false; 151 | take_function(F, A, [{F, A, _} = H | T], Acc) -> 152 | {H, lists:reverse(Acc, T)}; 153 | take_function(F, A, [H | T], Acc) -> 154 | take_function(F, A, T, [H | Acc]). 155 | 156 | nif_id(Module) -> 157 | atom_to_list(Module) ++ "_nif". 158 | 159 | % Get the app name, this is needed at runtime to retrieve the priv_dir 160 | app_name(Options, AppDir) -> 161 | case proplists:get_value(application, Options) of 162 | undefined -> 163 | % If the user didn't specify an application name, we have to get one 164 | AppSrc = filename:join([AppDir, "src", "*.app.src"]), 165 | {ok, [{_, AppName, _}]} = file:consult(hd(filelib:wildcard(AppSrc))), 166 | AppName; 167 | Value -> 168 | Value 169 | end. 170 | 171 | % The list of compiler flags used when calling gcc 172 | flags(NiffyOptions) -> 173 | string:join(lists:usort(proplists:get_value(flags, NiffyOptions)), " "). 174 | 175 | % Make sure we have an init function 176 | ensure_init_function(Module, Forms) -> 177 | ensure_init_function(Module, Forms, []). 178 | 179 | % Yes, this is assuming the last statement on the forms is an EOF 180 | ensure_init_function(Module, [], [Eof | Acc]) -> 181 | FName = list_to_atom(atom_to_list(Module) ++ "_nif_init"), 182 | L = lists:reverse([Eof, {function, 0, FName, 0, [{clause, 0, [], [], []}]} | 183 | Acc]), 184 | {P, S} = lists:split(3, L), 185 | {{FName, 0}, P ++ [{attribute, 0, on_load, {FName, 0}}] ++ S}; 186 | ensure_init_function(_Module, [{attribute, _, on_load, F} | _] = L, Acc) -> 187 | {F, lists:reverse(Acc, L)}; 188 | ensure_init_function(Module, [H | T], Acc) -> 189 | ensure_init_function(Module, T, [H | Acc]). 190 | 191 | % Assuming we have an init function, add the code to load the nif 192 | add_nif_loader(Forms, Func, NIF) -> 193 | add_nif_loader(Forms, Func, NIF, []). 194 | 195 | add_nif_loader([{function, L, F, A, [Clause]} | T], {F, A}, NIF, Acc) -> 196 | {clause, L2, Args, [], Body} = Clause, 197 | NewClause = {clause, L2, Args, [], [make_nif_loader(L, NIF) | Body]}, 198 | NewF = {function, L, F, A, [NewClause]}, 199 | lists:reverse([NewF | Acc], T); 200 | add_nif_loader([H | T], Func, NIF, Acc) -> 201 | add_nif_loader(T, Func, NIF, [H | Acc]). 202 | 203 | %%============================================================================== 204 | %% Code generators 205 | %%============================================================================== 206 | get_function_stub(Line1, Line2, Name, Arity, Args) -> 207 | Body = {call, Line2, {atom, Line2, throw}, [{atom, Line2, nif_not_loaded}]}, 208 | {function, Line1, Name, Arity, [{clause, Line1, Args, [], [Body]}]}. 209 | 210 | make_nif_loader(L, {AppName, NIF}) -> 211 | % The code this is generating is just: 212 | % erlang:load_nif(niffy:nif_filename(AppName, NIF), 0) 213 | Args = [{call, L, 214 | {remote, L, {atom, L, niffy}, {atom, L, nif_filename}}, 215 | [{atom, L, AppName}, {string, L, NIF}]}, 216 | {integer, L, 0}], 217 | {match, L, {atom, L, ok}, 218 | {call, L, {remote, L, {atom, L, erlang}, 219 | {atom, L, load_nif}}, Args}}. 220 | 221 | build_c_code(Mod, Functions, Options) -> 222 | Includes = proplists:get_value(includes, Options), 223 | {NewIncludes, NewFunctions} = includes(Functions, ["erl_nif.h" | Includes]), 224 | NIFIds = [["{\"", atom_to_list(F), "\", ", 225 | integer_to_list(A), ", ", 226 | atom_to_list(F), "_nif, ", 227 | func_flags(DirtyMode), 228 | "}"] || {F, A, DirtyMode, _} <- NewFunctions], 229 | [string:join(NewIncludes, "\n"), "\n\n", 230 | string:join([build_c_function(F, Options) || F <- NewFunctions], "\n"), "\n", 231 | "static ErlNifFunc niffuncs[] = {", 232 | string:join(NIFIds, [",\n", lists:duplicate(32, 32)]), "};\n\n", 233 | "ERL_NIF_INIT(", atom_to_list(Mod), ", niffuncs, ", 234 | proplists:get_value(on_load, Options), 235 | ", NULL, ", 236 | proplists:get_value(on_upgrade, Options), ", ", 237 | proplists:get_value(on_unload, Options), ")\n"]. 238 | 239 | build_c_function({F, _, _, Function}, Options) -> 240 | Name = atom_to_list(F), 241 | Body = body(Function), 242 | % Get the function that transforms the return value to an erlang term 243 | ReturnReplacement = build_make_type(return_type(Function, Name)), 244 | % And apply it (via regex) to all returns on the function body 245 | FixedBody = re:replace(Body, 246 | "return\s+(?!enif_make)([^;\n]*);", 247 | ReturnReplacement, 248 | [global]), 249 | ["static ERL_NIF_TERM ", atom_to_list(F), 250 | "_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])\n", "{\n", 251 | build_argument_getters(Function, Options), 252 | FixedBody, "}\n"]. 253 | 254 | func_flags(cpu_bound) -> 255 | "ERL_NIF_DIRTY_JOB_CPU_BOUND"; 256 | func_flags(io_bound) -> 257 | "ERL_NIF_DIRTY_JOB_IO_BOUND"; 258 | func_flags(_None) -> 259 | $0. 260 | 261 | %%============================================================================== 262 | %% C code utils 263 | %%============================================================================== 264 | build_make_type("ERL_NIF_TERM") -> 265 | "return \\1;"; 266 | build_make_type("bool") -> 267 | "return enif_make_atom(env, \\1 ? \"true\" : \"false\");"; 268 | build_make_type("_Bool") -> 269 | build_make_type("bool"); 270 | build_make_type(Type) -> 271 | "return enif_make_" ++ 272 | proplists:get_value(Type, numeric_type_mapping()) ++ 273 | "(env, \\1);". 274 | 275 | numeric_type_mapping() -> 276 | [{"int", "int"}, 277 | {"ErlNifSInt64", "int64"}, 278 | {"double", "double"}, 279 | {"long int", "long"}, 280 | {"unsigned int", "uint"}, 281 | {"ErlNifUInt64", "uint64"}, 282 | {"unsigned long", "ulong"}]. 283 | 284 | % The body of the function is assumed to be anything within the outmost brackets 285 | body(Function) -> 286 | % Get the position of the outmost brackets 287 | OpeningBracket = string:chr(Function, ${), 288 | ClosingBracket = string:rchr(Function, $}), 289 | % Get the spaces we have in front of the first bracket 290 | BeforeOpeningBracket = string:sub_string(Function, 1, OpeningBracket - 1), 291 | Tab = string:sub_string(Function, 292 | string:rchr(BeforeOpeningBracket, $\n) + 1, 293 | OpeningBracket - 1), 294 | % Get the body 295 | Body = string:sub_string(Function, OpeningBracket + 1, ClosingBracket - 1), 296 | % Divide the body in lines and remove all extra spaces on each line 297 | Lines = [Line -- Tab || Line <- string:tokens(Body, "\n")], 298 | % Put the newline characters back 299 | string:join(Lines, "\n"). 300 | 301 | return_type(Body, FName) -> 302 | string:strip(string:substr(Body, 1, string:str(Body, FName) - 1), both). 303 | 304 | build_argument_getters(Function, Options) -> 305 | case args(Function) of 306 | % Do nothing for functions with no parameters 307 | [] -> 308 | ""; 309 | % Special case to handle when the user doesn't want any parameter magic 310 | [{"ErlNifEnv*", "env"}, 311 | {"int", "argc"}, 312 | {"const ERL_NIF_TERM", "argv[]"}] -> 313 | ""; 314 | % Try to convert the standard C types to the getter functions from erl_nif.h 315 | Args -> 316 | [" // Actual variable declarations from the parameters\n", 317 | string:join([[" ", handle_const_char(T), " ", N, $;] || 318 | {T, N} <- Args], "\n"), 319 | "\n // Assigning the contents of 'env' to the variables", 320 | case lists:any(fun({"const char*", _}) -> 321 | true; 322 | (_) -> 323 | false 324 | end, Args) of 325 | true -> 326 | "\n unsigned int internal_str_length;"; 327 | false -> 328 | "" 329 | end, "\n", build_argument_getters(Args, Options, 0, []), 330 | "\n // Your actual (mostly untached) code\n"] 331 | end. 332 | 333 | handle_const_char("const char*") -> 334 | "char*"; 335 | handle_const_char(Other) -> 336 | Other. 337 | 338 | build_argument_getters([], _Options, _, Acc) -> 339 | string:join(lists:reverse(Acc), ["\n"]); 340 | build_argument_getters([{"const char*", Name} | T], Options, I, Acc) -> 341 | IStr = integer_to_list(I), 342 | Get = case get_type_from_name(Name, Options) of 343 | string -> 344 | [" if (!enif_get_list_length(env, argv[", IStr, "], " 345 | "&internal_str_length))\n", 346 | " return enif_make_badarg(env);\n", 347 | " ", Name, " = malloc(internal_str_length + 1);\n" 348 | " if (!", Name, ")\n return enif_raise_exception(env, ", 349 | "enif_make_atom(env, \"malloc_error\"));\n", 350 | " if (!enif_get_string(env, argv[", IStr, "], ", 351 | Name, ", ", 352 | integer_to_list(proplists:get_value(max_string_size, Options)), 353 | ", ", proplists:get_value(string_encoding, Options), "))\n", 354 | " return enif_make_badarg(env);"] 355 | end, 356 | build_argument_getters(T, Options, I + 1, [Get | Acc]); 357 | build_argument_getters([{Type, Name} | T], Options, I, Acc) -> 358 | NewEnifGet = build_numeric_enif_get(I, Type, Name, Options), 359 | build_argument_getters(T, Options, I + 1, [NewEnifGet | Acc]). 360 | 361 | get_type_from_name(Name, Options) -> 362 | LName = string:to_lower(Name), 363 | case lists:suffix("string", LName) orelse 364 | lists:suffix("str", LName) of 365 | true -> 366 | string; 367 | false -> 368 | case lists:suffix("atom", LName) of 369 | true -> 370 | atom; 371 | false -> 372 | case lists:suffix("binary", LName) orelse 373 | lists:suffix("bin", LName) of 374 | true -> 375 | string; 376 | false -> 377 | string 378 | %proplists:get_value(default_string_type, Options) 379 | end 380 | end 381 | end. 382 | 383 | build_numeric_enif_get(I, Type, Name, _Options) -> 384 | [" if (!", ["enif_get_", proplists:get_value(Type, numeric_type_mapping())], 385 | "(env, argv[", integer_to_list(I), "], &", Name, "))\n", 386 | " return enif_make_badarg(env);"]. 387 | 388 | args(Function) -> 389 | ArgsStr = string:sub_string(Function, string:chr(Function, $() + 1, 390 | string:chr(Function, $)) - 1), 391 | [case string:tokens(A, " ") of 392 | [T, N] -> {T, N}; 393 | [T1, T2, N] -> {T1 ++ " " ++ T2, N} 394 | end || A <- string:tokens(ArgsStr, ",")]. 395 | 396 | includes(Functions, Included) -> 397 | lists:foldr(fun(Function, {NewIncludes, NewFunctions}) -> 398 | {Includes, NewFunction} = includes(Function), 399 | {lists:usort(Includes ++ NewIncludes), 400 | [NewFunction | NewFunctions]} 401 | end, {[format_include(I) || I <- Included], []}, Functions). 402 | 403 | includes({F, A, DirtyMode, Body}) -> 404 | {Includes, Rest} = lists:partition(fun([$# | _]) -> true; 405 | (_) -> false 406 | end, string:tokens(Body, "\n")), 407 | {Includes, {F, A, DirtyMode, string:join(Rest, "\n")}}. 408 | 409 | format_include([$< | _] = File) -> "#include " ++ File; 410 | format_include(File) -> "#include \"" ++ File ++ "\"". --------------------------------------------------------------------------------