feat: Add async event handling (callbacks) code.

Instead of synchronously handling events as they happen in
`tox_iterate`, this first collects all events in a structure and then
lets the client process them. This allows clients to process events in
parallel, since the data structure returned is mostly immutable. Message
buffers are returned non-const so clients can steal them (but only until
they call `tox_events_free`, which frees all internal pointers,
including byte buffers).

This also makes toxcore compatible with languages that don't (easily)
support callbacks from C into the non-C language.

CMakeLists.txt

@@ -161,6 +161,7 @@ set(toxcore_PKGCONFIG_REQUIRES)
 # LAYER 1: Crypto core
 # --------------------
 set(toxcore_SOURCES ${toxcore_SOURCES}
+  toxcore/ccompat.c
   toxcore/ccompat.h
   toxcore/crypto_core.c
   toxcore/crypto_core.h)
@@ -240,10 +241,22 @@ set(toxcore_SOURCES ${toxcore_SOURCES}
 set(toxcore_SOURCES ${toxcore_SOURCES}
   toxcore/tox_api.c
   toxcore/tox.c
-  toxcore/tox_private.h
-  toxcore/tox.h)
+  toxcore/tox.h
+  toxcore/tox_events.c
+  toxcore/tox_events.h
+  toxcore/tox_private.h)
 set(toxcore_API_HEADERS ${toxcore_API_HEADERS} ${toxcore_SOURCE_DIR}/toxcore/tox.h^tox)
 
+# LAYER 9: New async events API
+# -------------------
+set(toxcore_SOURCES ${toxcore_SOURCES}
+  toxcore/events/friend_message.c
+  toxcore/events/internal.c
+  toxcore/events/internal.h
+  toxcore/tox_events.c
+  toxcore/tox_events.h)
+set(toxcore_API_HEADERS ${toxcore_API_HEADERS} ${toxcore_SOURCE_DIR}/toxcore/tox_events.h^tox)
+
 ################################################################################
 #
 # :: Audio/Video Library
@@ -441,6 +454,7 @@ auto_test(save_load)
 auto_test(send_message)
 auto_test(set_name)
 auto_test(set_status_message)
+auto_test(tox_events)
 auto_test(tox_many)
 auto_test(tox_many_tcp)
 auto_test(tox_one)

auto_tests/BUILD.bazel

@@ -61,6 +61,7 @@ flaky_tests = {
         "//c-toxcore/toxcore:onion",
         "//c-toxcore/toxcore:onion_announce",
         "//c-toxcore/toxcore:onion_client",
+        "//c-toxcore/toxcore:tox_events",
         "//c-toxcore/toxencryptsave",
         "@libsodium",
         "@libvpx",

auto_tests/tox_events_test.c

@@ -0,0 +1,105 @@
+/* Auto Tests: Many clients.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+
+#include "../testing/misc_tools.h"
+#include "../toxcore/tox.h"
+#include "../toxcore/tox_events.h"
+#include "check_compat.h"
+
+static bool await_message(Tox **toxes)
+{
+    for (uint32_t i = 0; i < 100; ++i) {
+        // Ignore events on tox 1.
+        tox_events_free(tox_events_iterate(toxes[0]));
+        // Check if tox 2 got the message from tox 1.
+        Tox_Events *events = tox_events_iterate(toxes[1]);
+
+        if (events != nullptr) {
+            ck_assert(tox_events_get_friend_messages_size(events) == 1);
+            const Tox_Event_Friend_Message *msg_event = tox_events_get_friend_message(events, 0);
+            ck_assert(tox_event_friend_message_get_message_length(msg_event) == sizeof("hello"));
+            const uint8_t *msg = tox_event_friend_message_get_message(msg_event);
+            ck_assert_msg(memcmp(msg, "hello", sizeof("hello")) == 0,
+                          "message was not expected 'hello' but '%s'", (const char *)msg);
+            tox_events_free(events);
+            return true;
+        }
+
+        c_sleep(tox_iteration_interval(toxes[0]));
+    }
+
+    return false;
+}
+
+static void test_tox_events(void)
+{
+    uint8_t message[sizeof("hello")];
+    memcpy(message, "hello", sizeof(message));
+
+    Tox *toxes[2];
+    uint32_t index[2];
+
+    for (uint32_t i = 0; i < 2; ++i) {
+        index[i] = i + 1;
+        toxes[i] = tox_new_log(nullptr, nullptr, &index[i]);
+        tox_events_init(toxes[i]);
+        ck_assert_msg(toxes[i] != nullptr, "failed to create tox instances %u", i);
+    }
+
+    uint8_t pk[TOX_PUBLIC_KEY_SIZE];
+    tox_self_get_dht_id(toxes[0], pk);
+    tox_bootstrap(toxes[1], "localhost", tox_self_get_udp_port(toxes[0], nullptr), pk, nullptr);
+
+    tox_self_get_public_key(toxes[0], pk);
+    tox_friend_add_norequest(toxes[1], pk, nullptr);
+
+    tox_self_get_public_key(toxes[1], pk);
+    tox_friend_add_norequest(toxes[0], pk, nullptr);
+
+    printf("bootstrapping and connecting 2 toxes\n");
+
+    while (tox_self_get_connection_status(toxes[0]) == TOX_CONNECTION_NONE ||
+            tox_self_get_connection_status(toxes[1]) == TOX_CONNECTION_NONE) {
+        // Ignore connection events for now.
+        tox_events_free(tox_events_iterate(toxes[0]));
+        tox_events_free(tox_events_iterate(toxes[1]));
+
+        c_sleep(tox_iteration_interval(toxes[0]));
+    }
+
+    printf("toxes online, waiting for friend connection\n");
+
+    while (tox_friend_get_connection_status(toxes[0], 0, nullptr) == TOX_CONNECTION_NONE ||
+            tox_friend_get_connection_status(toxes[1], 0, nullptr) == TOX_CONNECTION_NONE) {
+        // Ignore connection events for now.
+        tox_events_free(tox_events_iterate(toxes[0]));
+        tox_events_free(tox_events_iterate(toxes[1]));
+
+        c_sleep(tox_iteration_interval(toxes[0]));
+    }
+
+    printf("friends are connected via %s, now sending message\n",
+           tox_friend_get_connection_status(toxes[0], 0, nullptr) == TOX_CONNECTION_TCP ? "TCP" : "UDP");
+
+    Tox_Err_Friend_Send_Message err;
+    tox_friend_send_message(toxes[0], 0, TOX_MESSAGE_TYPE_NORMAL, message, sizeof(message), &err);
+    ck_assert(err == TOX_ERR_FRIEND_SEND_MESSAGE_OK);
+
+    ck_assert(await_message(toxes));
+
+    for (uint32_t i = 0; i < 2; ++i) {
+        tox_kill(toxes[i]);
+    }
+}
+
+int main(void)
+{
+    setvbuf(stdout, nullptr, _IONBF, 0);
+    test_tox_events();
+    return 0;
+}

other/docker/autotools/run

@@ -0,0 +1,3 @@
+#!/bin/sh
+
+docker build -t toxchat/toxcore-autotools -f other/docker/autotools/Dockerfile .

other/docker/circleci/Dockerfile

@@ -10,6 +10,7 @@ RUN apt-get update && \
  libopus-dev \
  libsodium-dev \
  libvpx-dev \
+ llvm-dev \
  ninja-build \
  pkg-config \
  && apt-get clean \

other/docker/circleci/run

@@ -0,0 +1,6 @@
+#!/bin/sh
+
+SANITIZER="${1:-asan}"
+
+docker build -t toxchat/toxcore-circleci other/docker/circleci
+docker run --rm -it -v "$PWD:/c-toxcore" toxchat/toxcore-circleci "$SANITIZER"

toxcore/BUILD.bazel

@@ -10,6 +10,7 @@ exports_files(
 
 cc_library(
     name = "ccompat",
+    srcs = ["ccompat.c"],
     hdrs = ["ccompat.h"],
     visibility = ["//c-toxcore:__subpackages__"],
 )
@@ -459,6 +460,20 @@ cc_library(
     ],
 )
 
+cc_library(
+    name = "tox_events",
+    srcs = ["tox_events.c"] + glob([
+        "events/*.c",
+        "events/*.h",
+    ]),
+    hdrs = ["tox_events.h"],
+    visibility = ["//c-toxcore:__subpackages__"],
+    deps = [
+        ":ccompat",
+        ":toxcore",
+    ],
+)
+
 sh_library(
     name = "cimple_files",
     srcs = glob([

toxcore/Makefile.inc

@@ -6,6 +6,9 @@ libtoxcore_la_include_HEADERS = \
 libtoxcore_la_includedir = $(includedir)/tox
 
 libtoxcore_la_SOURCES = ../toxcore/ccompat.h \
+                        ../toxcore/events/internal.h \
+                        ../toxcore/events/internal.c \
+                        ../toxcore/events/friend_message.c \
                         ../toxcore/DHT.h \
                         ../toxcore/DHT.c \
                         ../toxcore/mono_time.h \
@@ -31,8 +34,10 @@ libtoxcore_la_SOURCES = ../toxcore/ccompat.h \
                         ../toxcore/state.h \
                         ../toxcore/state.c \
                         ../toxcore/tox.h \
-                        ../toxcore/tox_private.h \
                         ../toxcore/tox.c \
+                        ../toxcore/tox_events.h \
+                        ../toxcore/tox_events.c \
+                        ../toxcore/tox_private.h \
                         ../toxcore/tox_api.c \
                         ../toxcore/util.h \
                         ../toxcore/util.c \

toxcore/ccompat.c

@@ -0,0 +1,15 @@
+#include "ccompat.h"
+
+#include <stdlib.h>
+#include <string.h>
+
+void *salloc(uint32_t size, const void *default_value)
+{
+    void *ptr = malloc(size);
+
+    if (ptr != nullptr) {
+        memcpy(ptr, default_value, size);
+    }
+
+    return ptr;
+}

toxcore/ccompat.h

@@ -10,6 +10,7 @@
 
 #include <assert.h>
 #include <stdbool.h>
+#include <stdint.h>
 
 bool unused_for_tokstyle(void);
 
@@ -59,8 +60,12 @@ bool unused_for_tokstyle(void);
 #ifndef static_assert
 #define static_assert(cond, msg) extern const int unused_for_static_assert
 #endif
+#define new(T) (T *)salloc(sizeof(T), &(T){0})
+#define delete(obj) free(obj)
 #endif
 
+void *salloc(uint32_t size, const void *default_value);
+
 #ifdef __GNUC__
 #define GNU_PRINTF(f, a) __attribute__((__format__(__printf__, f, a)))
 #else