/*
 * Sanity check of libcdecl multithread safety.
 *
 * Copyright © 2024 Nick Bowler
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */

#include <config.h>
#include <assert.h>
#include "cdecl-internal.h"
#include "errmsg.h"
#include "tap.h"

/*
 * Function called from output.c but not needed for error messaging.
 */
const char *cdecl__token_name(unsigned token)
{
	tap_bail_out("stub cdecl__token_name called");
}

/*
 * Prior returned value from cdecl_get_error in the main thread.
 */
static const struct cdecl_error *thread1_err;

/*
 * Check that the error code and message matches expectations (noting that
 * this application does not call setlocale to enable translations).
 */
static void check_simple_err(const struct cdecl_error *err, unsigned t,
                             unsigned exp_code, unsigned msg_id)
{
	static const char errmsgs[] = STRTAB_INITIALIZER;
	const char *exp_msg;

	if (!tap_result(err->code == exp_code, "thread[%u] err->code", t)) {
		tap_diag("Failed, unexpected result");
		tap_diag("   Received: %u", err->code);
		tap_diag("   Expected: %u", exp_code);
	}

	exp_msg = &errmsgs[msg_id];
	if (!tap_result(!strcmp(err->str, exp_msg), "thread[%u] err->str", t)) {
		tap_diag("Failed, unexpected result");
		tap_diag("   Received: %.*s", (int)strlen(exp_msg), err->str);
		tap_diag("   Expected: %s", exp_msg);
	}
}

static void thread2_func(void)
{
	const struct cdecl_error *err;

	cdecl__errmsg(CDECL__ENOTYPE);
	err = cdecl_get_error();

	/*
	 * Ensure that the error returned in this new thread is distinct from
	 * the error returned in the main thread.
	 */
	tap_diag("thread[2] err: %p", (void *)err);
	tap_result(thread1_err != err, "thread[2] new state");

	check_simple_err(err, 2, CDECL_ENOPARSE, CDECL__ENOTYPE);

	tap_diag("thread[2] exit");
}

#if USE_POSIX_THREADS || USE_ISOC_AND_POSIX_THREADS
#define THREAD_API "posix"
#include <pthread.h>

static void *thread2(void *p)
{
	thread2_func();
	return 0;
}

static void run_thread2(void)
{
	pthread_t t;
	int err;

	if (!(err = pthread_create(&t, 0, thread2, 0)))
		if (!(err = pthread_join(t, 0)))
			return;

	tap_bail_out("run_thread2 failed: %s", strerror(err));
}

#elif USE_ISOC_THREADS
#define THREAD_API "isoc"
#include <threads.h>

static int thread2(void *p)
{
	thread2_func();
	return 0;
}

static void run_thread2(void)
{
	thrd_t t;
	if (thrd_create(&t, thread2, 0) == thrd_success)
		if (thrd_join(t, 0) == thrd_success)
			return;

	tap_bail_out("run_thread2 failed");
}

#elif USE_WINDOWS_THREADS
#define THREAD_API "windows"
#define WIN32_LEAN_AND_MEAN
#include <windows.h>

static DWORD WINAPI thread2(LPVOID p)
{
	thread2_func();
	return 0;
}

static void run_thread2(void)
{
	HANDLE h;
	DWORD rc;

	if ((h = CreateThread(NULL, 0, thread2, NULL, 0, &rc))) {
		do {
			if (GetExitCodeThread(h, &rc) && rc != STILL_ACTIVE) {
				CloseHandle(h);
				return;
			}
		} while (WaitForSingleObject(h, INFINITE) != WAIT_FAILED);
	}

	tap_bail_out("run_thread2 failed (%lu)", GetLastError());
}
#else
#undef THREAD_API
int main(void)
{
	tap_skip_all("multithreading support disabled");
}
#endif

#ifdef THREAD_API
int main(void)
{
	size_t test_live_allocations(void);
	const struct cdecl_error *err;

	tap_diag("using thread API: " THREAD_API);
	tap_plan(9);

	/* Simulate an error in the main thread. */
	cdecl__errmsg(CDECL__ENOMEM);
	thread1_err = cdecl_get_error();
	tap_diag("thread[1] err: %p", (void *)thread1_err);
	check_simple_err(thread1_err, 1, CDECL_ENOMEM, CDECL__ENOMEM);

	run_thread2();

	/*
	 * Back in the main thread, the error previously returned by
	 * cdecl_get_error() should still be valid.
	 */
	check_simple_err(thread1_err, 1, CDECL_ENOMEM, CDECL__ENOMEM);

	/*
	 * Moreover, cdecl_get_error should return the same pointer it did
	 * last time (undocumented implementation detail).
	 */
	if (!tap_result((err = cdecl_get_error()) == thread1_err,
	                "thread[1] unchanged state"))
	{
		tap_diag("Failed, unexpected result");
		tap_diag("   Received: %p", (void *)err);
		tap_diag("   Expected: %p", (void *)thread1_err);
	}

	/*
	 * Main thread allocation should be the only one left.
	 */
	tap_result(test_live_allocations() == 1, "thread cleanup");
	tap_done();
}
#endif