Add sdl_hints:add_callback/3 function

This also sets up esdl2 to start accepting callbacks.
The module/process esdl2_callbacks must always be running
for that purpose, so esdl2 was made an OTP application
instead of a simple library.

Implementation of the rest of SDL_hints will follow in
subsequent commits.

3 files changed, 143 insertions, 0 deletions

diff --git a/c_src/esdl2.h b/c_src/esdl2.h
index 530abc4..df16664 100644
--- a/c_src/esdl2.h
+++ b/c_src/esdl2.h
@@ -27,6 +27,7 @@
 	A(blend) \
 	A(borderless) \
 	A(button) \
+	A(callback) \
 	A(caps) \
 	A(centered) \
 	A(charged) \
@@ -133,6 +134,8 @@
 
 #define NIF_FUNCTION_NAME(f) esdl2_ ## f
 #define NIF_FUNCTIONS(F) \
+	/* internal */ \
+	F(register_callback_process, 0) \
 	/* sdl */ \
 	F(init, 1) \
 	F(init_subsystem, 1) \
@@ -166,6 +169,8 @@
 	/* sdl_gl */ \
 	F(gl_create_context, 1) \
 	F(gl_swap_window, 1) \
+	/* sdl_hints */ \
+	F(add_hint_callback, 3) \
 	/* sdl_keyboard */ \
 	F(is_text_input_active, 0) \
 	F(start_text_input, 0) \
@@ -254,6 +259,8 @@ NIF_FUNCTIONS(NIF_FUNCTION_H_DECL)
 
 // --
 
+ErlNifPid* get_callback_process();
+
 #define sdl_error_tuple(env) \
 	enif_make_tuple2(env, \
 		atom_error, \
diff --git a/c_src/internal.c b/c_src/internal.c
new file mode 100644
index 0000000..0c58476
--- /dev/null
+++ b/c_src/internal.c
@@ -0,0 +1,35 @@
+// Copyright (c) 2015, Loïc Hoguin <[email protected]>
+//
+// Permission to use, copy, modify, and/or distribute this software for any
+// purpose with or without fee is hereby granted, provided that the above
+// copyright notice and this permission notice appear in all copies.
+//
+// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+// WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+// MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+// ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+// WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+// ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+// OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+
+#include "esdl2.h"
+
+// @todo Make thread-safe.
+
+// register_callback_process
+
+ErlNifPid callback_process;
+
+NIF_FUNCTION(register_callback_process)
+{
+	BADARG_IF(!enif_self(env, &callback_process));
+
+	return atom_ok;
+}
+
+// get_callback_process
+
+ErlNifPid* get_callback_process()
+{
+	return &callback_process;
+}
diff --git a/c_src/sdl_hints.c b/c_src/sdl_hints.c
new file mode 100644
index 0000000..fe4eceb
--- /dev/null
+++ b/c_src/sdl_hints.c
@@ -0,0 +1,101 @@
+// Copyright (c) 2015, Loïc Hoguin <[email protected]>
+//
+// Permission to use, copy, modify, and/or distribute this software for any
+// purpose with or without fee is hereby granted, provided that the above
+// copyright notice and this permission notice appear in all copies.
+//
+// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+// WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+// MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+// ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+// WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+// ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+// OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+
+#include "esdl2.h"
+
+// SDL_HintCallback
+
+typedef struct esdl2_callback {
+	char* module;
+	char* function;
+} esdl2_callback;
+
+void esdl2_hint_callback(void* userdata, const char* name, const char* oldValue, const char* newValue)
+{
+	ErlNifEnv* env = enif_alloc_env();
+	esdl2_callback* callback = (esdl2_callback*)userdata;
+	ERL_NIF_TERM old;
+	ERL_NIF_TERM new;
+
+	if (oldValue == NULL)
+		old = atom_undefined;
+	else
+		old = enif_make_string(env, oldValue, ERL_NIF_LATIN1);
+
+	if (newValue == NULL)
+		new = atom_undefined;
+	else
+		new = enif_make_string(env, newValue, ERL_NIF_LATIN1);
+
+	enif_send(NULL, get_callback_process(), env,
+		enif_make_tuple4(env, atom_callback,
+			enif_make_atom(env, callback->module),
+			enif_make_atom(env, callback->function),
+			enif_make_list3(env,
+				enif_make_string(env, name, ERL_NIF_LATIN1),
+				old,
+				new)));
+
+	enif_free_env(env);
+}
+
+// add_hint_callback
+// @todo We must free the userdata in SDL_DelHintCallback.
+
+NIF_CAST_HANDLER(thread_add_hint_callback)
+{
+	esdl2_callback* callback = (esdl2_callback*)enif_alloc(sizeof(esdl2_callback));
+
+	callback->module = args[1];
+	callback->function = args[2];
+
+	SDL_AddHintCallback(args[0], &esdl2_hint_callback, callback);
+
+	enif_free(args[0]);
+}
+
+NIF_FUNCTION(add_hint_callback)
+{
+	unsigned int hint_len, module_len, function_len;
+	char* hint;
+	char* module;
+	char* function;
+
+	BADARG_IF(!enif_get_list_length(env, argv[0], &hint_len));
+	BADARG_IF(!enif_get_atom_length(env, argv[1], &module_len, ERL_NIF_LATIN1));
+	BADARG_IF(!enif_get_atom_length(env, argv[2], &function_len, ERL_NIF_LATIN1));
+
+	hint = (char*)enif_alloc(hint_len + 1);
+	if (!enif_get_string(env, argv[0], hint, hint_len + 1, ERL_NIF_LATIN1)) {
+		enif_free(hint);
+		return enif_make_badarg(env);
+	}
+
+	module = (char*)enif_alloc(module_len + 1);
+	if (!enif_get_atom(env, argv[1], module, module_len + 1, ERL_NIF_LATIN1)) {
+		enif_free(hint);
+		enif_free(module);
+		return enif_make_badarg(env);
+	}
+
+	function = (char*)enif_alloc(function_len + 1);
+	if (!enif_get_atom(env, argv[2], function, function_len + 1, ERL_NIF_LATIN1)) {
+		enif_free(hint);
+		enif_free(module);
+		enif_free(function);
+		return enif_make_badarg(env);
+	}
+
+	return nif_thread_cast(env, thread_add_hint_callback, 3, hint, module, function);
+}