/*
    Copyright (c) 2005-2021 Intel Corporation

    Licensed under the Apache License, Version 2.0 (the "License");
    you may not use this file except in compliance with the License.
    You may obtain a copy of the License at

        http://www.apache.org/licenses/LICENSE-2.0

    Unless required by applicable law or agreed to in writing, software
    distributed under the License is distributed on an "AS IS" BASIS,
    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    See the License for the specific language governing permissions and
    limitations under the License.
*/

// The original source for this code is
// Copyright (c) 2011, Google Inc.
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
//     * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
//     * 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.
//     * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

#include <AvailabilityMacros.h>
#include <malloc/malloc.h>
#include <mach/mach.h>
#include <stdlib.h>

static kern_return_t enumerator(task_t, void *, unsigned, vm_address_t,
                                memory_reader_t, vm_range_recorder_t)
{
    return KERN_FAILURE;
}

static size_t good_size(malloc_zone_t *, size_t size)
{
    return size;
}

static boolean_t zone_check(malloc_zone_t *) /* Consistency checker */
{
    return true;
}

static void zone_print(malloc_zone_t *, boolean_t) { }
static void zone_log(malloc_zone_t *, void *) {}
static void zone_force_lock(malloc_zone_t *) {}
static void zone_force_unlock(malloc_zone_t *) {}

static void zone_statistics(malloc_zone_t *, malloc_statistics_t *s)
{
    s->blocks_in_use = 0;
    s->size_in_use = s->max_size_in_use = s->size_allocated = 0;
}

static boolean_t zone_locked(malloc_zone_t *)
{
    return false;
}

static boolean_t impl_zone_enable_discharge_checking(malloc_zone_t *)
{
    return false;
}

static void impl_zone_disable_discharge_checking(malloc_zone_t *) {}
static void impl_zone_discharge(malloc_zone_t *, void *) {}
static void impl_zone_destroy(struct _malloc_zone_t *) {}

/* note: impl_malloc_usable_size() is called for each free() call, so it must be fast */
static size_t impl_malloc_usable_size(struct _malloc_zone_t *, const void *ptr)
{
    // malloc_usable_size() is used by macOS* to recognize which memory manager
    // allocated the address, so our wrapper must not redirect to the original function.
    return __TBB_malloc_safer_msize(const_cast<void*>(ptr), NULL);
}

static void *impl_malloc(struct _malloc_zone_t *, size_t size);
static void *impl_calloc(struct _malloc_zone_t *, size_t num_items, size_t size);
static void *impl_valloc(struct _malloc_zone_t *, size_t size);
static void impl_free(struct _malloc_zone_t *, void *ptr);
static void *impl_realloc(struct _malloc_zone_t *, void *ptr, size_t size);
static void *impl_memalign(struct _malloc_zone_t *, size_t alignment, size_t size);

/* ptr is in zone and have reported size */
static void impl_free_definite_size(struct _malloc_zone_t*, void *ptr, size_t size)
{
    __TBB_malloc_free_definite_size(ptr, size);
}

/* Empty out caches in the face of memory pressure. */
static size_t impl_pressure_relief(struct _malloc_zone_t *, size_t  /* goal */)
{
    return 0;
}

static malloc_zone_t *system_zone = NULL;

struct DoMallocReplacement {
    DoMallocReplacement() {
        static malloc_introspection_t introspect;
        memset(&introspect, 0, sizeof(malloc_introspection_t));
        static malloc_zone_t zone;
        memset(&zone, 0, sizeof(malloc_zone_t));

        introspect.enumerator = &enumerator;
        introspect.good_size = &good_size;
        introspect.check = &zone_check;
        introspect.print = &zone_print;
        introspect.log = zone_log;
        introspect.force_lock = &zone_force_lock;
        introspect.force_unlock = &zone_force_unlock;
        introspect.statistics = zone_statistics;
        introspect.zone_locked = &zone_locked;
        introspect.enable_discharge_checking = &impl_zone_enable_discharge_checking;
        introspect.disable_discharge_checking = &impl_zone_disable_discharge_checking;
        introspect.discharge = &impl_zone_discharge;

        zone.size = &impl_malloc_usable_size;
        zone.malloc = &impl_malloc;
        zone.calloc = &impl_calloc;
        zone.valloc = &impl_valloc;
        zone.free = &impl_free;
        zone.realloc = &impl_realloc;
        zone.destroy = &impl_zone_destroy;
        zone.zone_name = "tbbmalloc";
        zone.introspect = &introspect;
        zone.version = 8;
        zone.memalign = impl_memalign;
        zone.free_definite_size = &impl_free_definite_size;
        zone.pressure_relief = &impl_pressure_relief;

        // make sure that default purgeable zone is initialized
        malloc_default_purgeable_zone();
        void* ptr = malloc(1);
        // get all registered memory zones
        unsigned zcount = 0;
        malloc_zone_t** zone_array = NULL;
        kern_return_t errorcode = malloc_get_all_zones(mach_task_self(),NULL,(vm_address_t**)&zone_array,&zcount);
        if (!errorcode && zone_array && zcount>0) {
            // find the zone that allocated ptr
            for (unsigned i=0; i<zcount; ++i) {
                malloc_zone_t* z = zone_array[i];
                if (z && z->size(z,ptr)>0) { // the right one is found
                    system_zone = z;
                    break;
                }
            }
        }
        free(ptr);

        malloc_zone_register(&zone);
        if (system_zone) {
            // after unregistration of the system zone, the last registered (i.e. our) zone becomes the default
            malloc_zone_unregister(system_zone);
            // register the system zone back
            malloc_zone_register(system_zone);
        }
    }
};

static DoMallocReplacement doMallocReplacement;