// Copyright 2015-2016 Espressif Systems (Shanghai) PTE LTD
//
// 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.
#include <string.h>
#include <sys/param.h>
#include <sdkconfig.h>

#define HEAP_TRACE_SRCFILE /* don't warn on inclusion here */
#include "esp_heap_trace.h"
#undef HEAP_TRACE_SRCFILE

#include "esp_heap_caps.h"
#include "esp_attr.h"
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "soc/soc_memory_layout.h"

#include "heap_private.h"

#define STACK_DEPTH CONFIG_HEAP_TRACING_STACK_DEPTH

static portMUX_TYPE trace_mux = portMUX_INITIALIZER_UNLOCKED;
static bool tracing;
static heap_trace_mode_t mode;

/* Buffer used for records, starting at offset 0
*/
static heap_trace_record_t *buffer;
static size_t total_records;

/* Count of entries logged in the buffer.

   Maximum total_records
*/
static size_t count;

/* Actual number of allocations logged */
static size_t total_allocations;

/* Actual number of frees logged */
static size_t total_frees;

/* Has the buffer overflowed and lost trace entries? */
static bool has_overflowed = false;

esp_err_t heap_trace_init_standalone(heap_trace_record_t *record_buffer, size_t num_records)
{
#ifndef CONFIG_HEAP_TRACING
    return ESP_ERR_NOT_SUPPORTED;
#endif

    if (tracing) {
        return ESP_ERR_INVALID_STATE;
    }
    buffer = record_buffer;
    total_records = num_records;
    memset(buffer, 0, num_records * sizeof(heap_trace_record_t));
    return ESP_OK;
}

esp_err_t heap_trace_start(heap_trace_mode_t mode_param)
{
#ifndef CONFIG_HEAP_TRACING
    return ESP_ERR_NOT_SUPPORTED;
#endif

    if (buffer == NULL || total_records == 0) {
        return ESP_ERR_INVALID_STATE;
    }
    portENTER_CRITICAL(&trace_mux);

    tracing = false;
    mode = mode_param;
    count = 0;
    total_allocations = 0;
    total_frees = 0;
    has_overflowed = false;
    heap_trace_resume();

    portEXIT_CRITICAL(&trace_mux);
    return ESP_OK;
}

static esp_err_t set_tracing(bool enable)
{
#ifndef CONFIG_HEAP_TRACING
    return ESP_ERR_NOT_SUPPORTED;
#endif
    if (tracing == enable) {
        return ESP_ERR_INVALID_STATE;
    }
    tracing = enable;
    return ESP_OK;
}

esp_err_t heap_trace_stop(void)
{
    return set_tracing(false);
}

esp_err_t heap_trace_resume(void)
{
    return set_tracing(true);
}

size_t heap_trace_get_count(void)
{
    return count;
}

esp_err_t heap_trace_get(size_t index, heap_trace_record_t *record)
{
#ifndef CONFIG_HEAP_TRACING
    return ESP_ERR_NOT_SUPPORTED;
#endif
    if (record == NULL) {
        return ESP_ERR_INVALID_STATE;
    }
    esp_err_t result = ESP_OK;

    portENTER_CRITICAL(&trace_mux);
    if (index >= count) {
        result = ESP_ERR_INVALID_ARG; /* out of range for 'count' */
    } else {
        memcpy(record, &buffer[index], sizeof(heap_trace_record_t));
    }
    portEXIT_CRITICAL(&trace_mux);
    return result;
}


void heap_trace_dump(void)
{
#ifndef CONFIG_HEAP_TRACING
    printf("no data, heap tracing is disabled.\n");
    return;
#endif
    size_t delta_size = 0;
    size_t delta_allocs = 0;
    printf("%u allocations trace (%u entry buffer)\n",
           count, total_records);
    size_t start_count = count;
    for (int i = 0; i < count; i++) {
        heap_trace_record_t *rec = &buffer[i];

        if (rec->address != NULL) {
            printf("%d bytes (@ %p) allocated CPU %d ccount 0x%08x caller ",
                   rec->size, rec->address, rec->ccount & 1, rec->ccount & ~3);
            for (int j = 0; j < STACK_DEPTH && rec->alloced_by[j] != 0; j++) {
                printf("%p%s", rec->alloced_by[j],
                       (j < STACK_DEPTH - 1) ? ":" : "");
            }

            if (mode != HEAP_TRACE_ALL || STACK_DEPTH == 0 || rec->freed_by[0] == NULL) {
                delta_size += rec->size;
                delta_allocs++;
                printf("\n");
            } else {
                printf("\nfreed by ");
                for (int j = 0; j < STACK_DEPTH; j++) {
                    printf("%p%s", rec->freed_by[j],
                           (j < STACK_DEPTH - 1) ? ":" : "\n");
                }
            }
        }
    }
    if (mode == HEAP_TRACE_ALL) {
        printf("%u bytes alive in trace (%u/%u allocations)\n",
               delta_size, delta_allocs, heap_trace_get_count());
    } else {
        printf("%u bytes 'leaked' in trace (%u allocations)\n", delta_size, delta_allocs);
    }
    printf("total allocations %u total frees %u\n", total_allocations, total_frees);
    if (start_count != count) { // only a problem if trace isn't stopped before dumping
        printf("(NB: New entries were traced while dumping, so trace dump may have duplicate entries.)\n");
    }
    if (has_overflowed) {
        printf("(NB: Buffer has overflowed, so trace data is incomplete.)\n");
    }
}

/* Add a new allocation to the heap trace records */
static IRAM_ATTR void record_allocation(const heap_trace_record_t *record)
{
    portENTER_CRITICAL(&trace_mux);
    if (tracing) {
        if (count == total_records) {
            has_overflowed = true;
            /* Move the whole buffer back one slot.

               This is a bit slow, compared to treating this buffer as a ringbuffer and rotating a head pointer.

               However, ringbuffer code gets tricky when we remove elements in mid-buffer (for leak trace mode) while
               trying to keep track of an item count that may overflow.
            */
            memmove(&buffer[0], &buffer[1], sizeof(heap_trace_record_t) * (total_records -1));
            count--;
        }
        // Copy new record into place
        memcpy(&buffer[count], record, sizeof(heap_trace_record_t));
        count++;
        total_allocations++;
    }
    portEXIT_CRITICAL(&trace_mux);
}

// remove a record, used when freeing
static void remove_record(int index);

/* record a free event in the heap trace log

   For HEAP_TRACE_ALL, this means filling in the freed_by pointer.
   For HEAP_TRACE_LEAKS, this means removing the record from the log.
*/
static IRAM_ATTR void record_free(void *p, void **callers)
{
    portENTER_CRITICAL(&trace_mux);
    if (tracing && count > 0) {
        total_frees++;
        /* search backwards for the allocation record matching this free */
        int i;
        for (i = count - 1; i >= 0; i--) {
            if (buffer[i].address == p) {
                break;
            }
        }

        if (i >= 0) {
            if (mode == HEAP_TRACE_ALL) {
                memcpy(buffer[i].freed_by, callers, sizeof(void *) * STACK_DEPTH);
            } else { // HEAP_TRACE_LEAKS
                // Leak trace mode, once an allocation is freed we remove it from the list
                remove_record(i);
            }
        }
    }
    portEXIT_CRITICAL(&trace_mux);
}

/* remove the entry at 'index' from the ringbuffer of saved records */
static IRAM_ATTR void remove_record(int index)
{
    if (index < count - 1) {
        // Remove the buffer entry from the list
        memmove(&buffer[index], &buffer[index+1],
                sizeof(heap_trace_record_t) * (total_records - index - 1));
    } else {
        // For last element, just zero it out to avoid ambiguity
        memset(&buffer[index], 0, sizeof(heap_trace_record_t));
    }
    count--;
}

/* Encode the CPU ID in the LSB of the ccount value */
inline static uint32_t get_ccount(void)
{
    uint32_t ccount = xthal_get_ccount() & ~3;
#ifndef CONFIG_FREERTOS_UNICORE
    ccount |= xPortGetCoreID();
#endif
    return ccount;
}

// Caller is 2 stack frames deeper than we care about
#define STACK_OFFSET  2

#define TEST_STACK(N) do {                                              \
        if (STACK_DEPTH == N) {                                         \
            return;                                                     \
        }                                                               \
        callers[N] = __builtin_return_address(N+STACK_OFFSET);                \
        if (!esp_ptr_executable(callers[N])) {                          \
            return;                                                     \
        }                                                               \
    } while(0);

/* Static function to read the call stack for a traced heap call.

   Calls to __builtin_return_address are "unrolled" via TEST_STACK macro as gcc requires the
   argument to be a compile-time constant.
*/
static IRAM_ATTR __attribute__((noinline)) void get_call_stack(void **callers)
{
    bzero(callers, sizeof(void *) * STACK_DEPTH);
    TEST_STACK(0);
    TEST_STACK(1);
    TEST_STACK(2);
    TEST_STACK(3);
    TEST_STACK(4);
    TEST_STACK(5);
    TEST_STACK(6);
    TEST_STACK(7);
    TEST_STACK(8);
    TEST_STACK(9);
}

_Static_assert(STACK_DEPTH >= 0 && STACK_DEPTH <= 10, "CONFIG_HEAP_TRACING_STACK_DEPTH must be in range 0-10");


typedef enum {
    TRACE_MALLOC_CAPS,
    TRACE_MALLOC_DEFAULT
} trace_malloc_mode_t;


void *__real_heap_caps_malloc(size_t size, uint32_t caps);
void *__real_heap_caps_malloc_default( size_t size );
void *__real_heap_caps_realloc_default( void *ptr, size_t size );

/* trace any 'malloc' event */
static IRAM_ATTR __attribute__((noinline)) void *trace_malloc(size_t size, uint32_t caps, trace_malloc_mode_t mode)
{
    uint32_t ccount = get_ccount();
    void *p;
    if ( mode == TRACE_MALLOC_CAPS ) {
        p = __real_heap_caps_malloc(size, caps);
    } else { //TRACE_MALLOC_DEFAULT
        p = __real_heap_caps_malloc_default(size);
    }

    if (tracing && p != NULL) {
        heap_trace_record_t rec = {
            .address = p,
            .ccount = ccount,
            .size = size,
        };
        get_call_stack(rec.alloced_by);
        record_allocation(&rec);
    }
    return p;
}

void __real_heap_caps_free(void *p);

/* trace any 'free' event */
static IRAM_ATTR __attribute__((noinline)) void trace_free(void *p)
{
    if (tracing && p != NULL) {
        void *callers[STACK_DEPTH];
        get_call_stack(callers);
        record_free(p, callers);
    }
    __real_heap_caps_free(p);
}

void * __real_heap_caps_realloc(void *p, size_t size, uint32_t caps);

/* trace any 'realloc' event */
static IRAM_ATTR __attribute__((noinline)) void *trace_realloc(void *p, size_t size, uint32_t caps, trace_malloc_mode_t mode)
{
    void *callers[STACK_DEPTH];
    uint32_t ccount = get_ccount();
    if (tracing && p != NULL && size == 0) {
        get_call_stack(callers);
        record_free(p, callers);
    }
    void *r;
    if (mode == TRACE_MALLOC_CAPS ) {
        r = __real_heap_caps_realloc(p, size, caps);
    } else { //TRACE_MALLOC_DEFAULT
        r = __real_heap_caps_realloc_default(p, size);
    }
    if (tracing && r != NULL) {
        get_call_stack(callers);
        if (p != NULL) {
            /* trace realloc as free-then-alloc */
            record_free(p, callers);
        }
        heap_trace_record_t rec = {
            .address = r,
            .ccount = ccount,
            .size = size,
        };
        memcpy(rec.alloced_by, callers, sizeof(void *) * STACK_DEPTH);
        record_allocation(&rec);
    }
    return r;
}

/* Note: this changes the behaviour of libc malloc/realloc/free a bit,
   as they no longer go via the libc functions in ROM. But more or less
   the same in the end. */

IRAM_ATTR void *__wrap_malloc(size_t size)
{
    return trace_malloc(size, 0, TRACE_MALLOC_DEFAULT);
}

IRAM_ATTR void __wrap_free(void *p)
{
    trace_free(p);
}

IRAM_ATTR void *__wrap_realloc(void *p, size_t size)
{
    return trace_realloc(p, size, 0, TRACE_MALLOC_DEFAULT);
}

IRAM_ATTR void *__wrap_calloc(size_t nmemb, size_t size)
{
    size = size * nmemb;
    void *result = trace_malloc(size, 0, TRACE_MALLOC_DEFAULT);
    if (result != NULL) {
        memset(result, 0, size);
    }
    return result;
}

IRAM_ATTR void *__wrap_heap_caps_malloc(size_t size, uint32_t caps)
{
    return trace_malloc(size, caps, TRACE_MALLOC_CAPS);
}

void __wrap_heap_caps_free(void *p) __attribute__((alias("__wrap_free")));

IRAM_ATTR void *__wrap_heap_caps_realloc(void *p, size_t size, uint32_t caps)
{
    return trace_realloc(p, size, caps, TRACE_MALLOC_CAPS);
}

IRAM_ATTR void *__wrap_heap_caps_malloc_default( size_t size )
{
    return trace_malloc(size, 0, TRACE_MALLOC_DEFAULT);
}

IRAM_ATTR void *__wrap_heap_caps_realloc_default( void *ptr, size_t size )
{
    return trace_realloc(ptr, size, 0, TRACE_MALLOC_DEFAULT);
}