except.c

/* Copyright 1998-2012
 * Kaz Kylheku <kaz@kylheku.com>
 * Vancouver, Canada
 * All rights reserved.
 *
 * BSD License:
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 *   1. Redistributions of source code must retain the above copyright
 *      notice, this list of conditions and the following disclaimer.
 *   2. Redistributions in binary form must reproduce the above copyright
 *      notice, this list of conditions and the following disclaimer in
 *      the documentation and/or other materials provided with the
 *      distribution.
 *   3. The name of the author may not be used to endorse or promote
 *      products derived from this software without specific prior
 *      written permission.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 */

#include <assert.h>
#include <stdlib.h>
#include <stdio.h>
#include <stdarg.h>
#include <limits.h>
#include "except.h"

#define XCEPT_BUFFER_SIZE       1024

#define group except_group
#define code except_code
#define id except_id
#define message except_message
#define dyndata except_dyndata
#define func except_func
#define context except_context
#define id except_id
#define size except_size
#define obj except_obj
#define jmp except_jmp
#define down except_down
#define type except_type
#define catcher except_catcher
#define cleanup except_cleanup
#define info except_info

#ifdef KAZLIB_POSIX_THREADS

#include <pthread.h>

static pthread_mutex_t init_mtx = PTHREAD_MUTEX_INITIALIZER;
static int init_counter;
static pthread_key_t top_key;
static pthread_key_t uh_key;
static pthread_key_t alloc_key;
static pthread_key_t dealloc_key;
static void unhandled_catcher(except_t *);

#define get_top() ((struct except_stacknode *) pthread_getspecific(top_key))
#define set_top(T) (pthread_setspecific(top_key, (T)), (void)((T) == (struct except_stacknode *) 0))
#define set_catcher(C) (pthread_setspecific(uh_key, (void *) (C)), (void)((C) == (void (*)(except_t *)) 0))
#define set_alloc(A) (pthread_setspecific(alloc_key, (void *) (A)), (void)((A) == (void *(*)(size_t)) 0))
#define set_dealloc(D) (pthread_setspecific(dealloc_key, (void *) (D)), (void)((D) == (void (*)(void *)) 0))

static void (*get_catcher(void))(except_t *)
{
    void (*catcher)(except_t *) = (void (*)(except_t *)) pthread_getspecific(uh_key);
    return (catcher == 0) ? unhandled_catcher : catcher;
}

static void *(*get_alloc(void))(size_t)
{
    void *(*alloc)(size_t) = (void *(*)(size_t)) pthread_getspecific(alloc_key);
    return (alloc == 0) ? malloc : alloc;
}

static void (*get_dealloc(void))(void *)
{
    void (*dealloc)(void *) = (void (*)(void *)) pthread_getspecific(dealloc_key);
    return (dealloc == 0) ? free : dealloc;
}

int except_init(void)
{
    int retval = 1;

    pthread_mutex_lock(&init_mtx);

    assert (init_counter < INT_MAX);

    if (init_counter++ == 0) {
        int top_ok = (pthread_key_create(&top_key, 0) == 0);
        int uh_ok = (pthread_key_create(&uh_key, 0) == 0);
        int alloc_ok = (pthread_key_create(&alloc_key, 0) == 0);
        int dealloc_ok = (pthread_key_create(&dealloc_key, 0) == 0);

        if (!top_ok || !uh_ok || !alloc_ok || !dealloc_ok) {
            retval = 0;
            init_counter = 0;
            if (top_ok)
                pthread_key_delete(top_key);
            if (uh_ok)
                pthread_key_delete(uh_key);
            if (alloc_ok)
                pthread_key_delete(alloc_key);
            if (dealloc_ok)
                pthread_key_delete(dealloc_key);
        }
    }

    pthread_mutex_unlock(&init_mtx);

    return retval;
}

void except_deinit(void)
{
    pthread_mutex_lock(&init_mtx);

    assert (init_counter > 0);

    if (--init_counter == 0) {
        pthread_key_delete(top_key);
        pthread_key_delete(uh_key);
        pthread_key_delete(alloc_key);
        pthread_key_delete(dealloc_key);
    }

    pthread_mutex_unlock(&init_mtx);
}

#else   /* no thread support */

static int init_counter;
static void unhandled_catcher(except_t *);
static void (*uh_catcher_ptr)(except_t *) = unhandled_catcher;
static void *(*allocator)(size_t) = malloc;
static void (*deallocator)(void *) = free;
static struct except_stacknode *stack_top;

#define get_top() (stack_top)
#define set_top(T) (stack_top = (T))
#define get_catcher() (uh_catcher_ptr)
#define set_catcher(C) (uh_catcher_ptr = (C))
#define get_alloc() (allocator)
#define set_alloc(A) (allocator = (A))
#define get_dealloc() (deallocator)
#define set_dealloc(D) (deallocator = (D))

int except_init(void)
{
    assert (init_counter < INT_MAX);
    init_counter++;
    return 1;
}

void except_deinit(void)
{
    assert (init_counter > 0);
    init_counter--;
}

#endif


static int match(const volatile except_id_t *thrown, const except_id_t *caught)
{
    int group_match = (caught->group == XCEPT_GROUP_ANY || caught->group == thrown->group);
    int code_match = (caught->code == XCEPT_CODE_ANY || caught->code == thrown->code);

    return group_match && code_match;
}

static void do_throw(except_t *except)
{
    struct except_stacknode *top;

    assert (except->id.group != 0 && except->id.code != 0);

    for (top = get_top(); top != 0; top = top->down) {
        if (top->type == XCEPT_CLEANUP) {
            top->info.cleanup->func(top->info.cleanup->context);
        } else {
            struct except_catch *catcher = top->info.catcher;
            const except_id_t *pi = catcher->id;
            size_t i;

            assert (top->type == XCEPT_CATCHER);
            except_free(catcher->obj.dyndata);

            for (i = 0; i < catcher->size; pi++, i++) {
                if (match(&except->id, pi)) {
                    catcher->obj = *except;
                    set_top(top);
                    longjmp(catcher->jmp, 1);
                }
            }
        }
    }

    set_top(top);
    get_catcher()(except);      /* unhandled exception */
    abort();
}

static void unhandled_catcher(except_t *except)
{
    fprintf(stderr, "Unhandled exception (\"%s\", group=%ld, code=%ld)\n",
            except->message, except->id.group, except->id.code);
    abort();
}

static void stack_push(struct except_stacknode *node)
{
    node->down = get_top();
    set_top(node);
}

void except_setup_clean(struct except_stacknode *esn,
        struct except_cleanup *ecl, void (*cleanf)(void *), void *context)
{
    esn->type = XCEPT_CLEANUP;
    ecl->func = cleanf;
    ecl->context = context;
    esn->info.cleanup = ecl;
    stack_push(esn);
}

void except_setup_try(struct except_stacknode *esn,
        struct except_catch *ech, const except_id_t id[], size_t size)
{
   ech->id = id;
   ech->size = size;
   ech->obj.dyndata = 0;
   esn->type = XCEPT_CATCHER;
   esn->info.catcher = ech;
   stack_push(esn);
}

struct except_stacknode *except_pop(void)
{
    struct except_stacknode *top = get_top();
    set_top(top->down);
    return top;
}

void except_rethrow(except_t *except)
{
    struct except_stacknode *top = get_top();
    assert (top != 0);
    assert (top->type == XCEPT_CATCHER);
    assert (&top->info.catcher->obj == except);
    set_top(top->down);
    do_throw(except);
}

void except_throw(long group, long code, const char *msg)
{
    except_t except;

    except.id.group = group;
    except.id.code = code;
    except.message = msg;
    except.dyndata = 0;

    do_throw(&except);
}

void except_throwd(long group, long code, const char *msg, void *data)
{
    except_t except;

    except.id.group = group;
    except.id.code = code;
    except.message = msg;
    except.dyndata = data;

    do_throw(&except);
}

void except_throwf(long group, long code, const char *fmt, ...)
{
    char *buf = (char *) except_alloc(XCEPT_BUFFER_SIZE);
    va_list vl;

    va_start (vl, fmt);
    vsprintf(buf, fmt, vl);
    va_end (vl);
    except_throwd(group, code, buf, buf);
}

void (*except_unhandled_catcher(void (*new_catcher)(except_t *)))(except_t *)
{
    void (*old_catcher)(except_t *) = get_catcher();
    set_catcher(new_catcher);
    return old_catcher;
}

#undef except_code
#undef except_group
#undef except_message
#undef except_data

unsigned long except_code(except_t *ex)
{
    return ex->id.code;
}

unsigned long except_group(except_t *ex)
{
    return ex->id.group;
}

const char *except_message(except_t *ex)
{
    return ex->message;
}

void *except_data(except_t *ex)
{
    return ex->dyndata;
}

void *except_take_data(except_t *ex)
{
    void *data = ex->dyndata;
    ex->dyndata = 0;
    return data;
}

void except_set_allocator(void *(*alloc)(size_t), void (*dealloc)(void *))
{
    set_alloc(alloc);
    set_dealloc(dealloc);
}

void *except_alloc(size_t size)
{
    void *ptr = get_alloc()(size);

    if (ptr == 0)
        except_throw(XCEPT_BAD_ALLOC, 0, "out of memory");
    return ptr;
}

void except_free(void *ptr)
{
    get_dealloc()(ptr);
}

#ifdef KAZLIB_TEST_MAIN

#include <stdio.h>
#include <ctype.h>

static void cleanup(void *arg)
{
    printf("cleanup(\"%s\") called\n", (char *) arg);
}

static void bottom_level(void)
{
    char buf[256];
    printf("throw exception? "); fflush(stdout);
    if (fgets(buf, sizeof buf, stdin) == 0)
        return;

    if (buf[0] >= 0 && toupper(buf[0]) == 'Y')
        except_throw(1, 1, "nasty exception");
}

static void top_level(void)
{
    except_cleanup_push(cleanup, (void *) "argument");
    bottom_level();
    except_cleanup_pop(0);
}

int main(void)
{
    static const except_id_t match[] = { { 1, 1 }, { 1, 2 } };
    except_t *ex;

    /*
     * Nested exception ``try blocks''
     */

    /* outer */
    except_try_push(match, 2, &ex);
    if (!ex) {
        /* inner */
        except_try_push(match, 2, &ex);
        if (!ex) {
            top_level();
        } else {
            /* inner catch */
            printf("caught exception (inner): \"%s\", s=%ld, c=%ld\n",
                    except_message(ex), except_group(ex), except_code(ex));
            except_rethrow(ex);
        }
        except_try_pop();
    } else {
        /* outer catch */
        printf("caught exception (outer): \"%s\", s=%ld, c=%ld\n",
                except_message(ex), except_group(ex), except_code(ex));
    }
    except_try_pop();
    except_throw(99, 99, "exception in main");
    return 0;
}


#endif