OVMS3-idf/components/log/log.c
2016-09-18 21:06:43 +08:00

313 lines
9.7 KiB
C

// 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.
/*
* Log library — implementation notes.
*
* Log library stores all tags provided to esp_log_set_level as a linked
* list. See uncached_tag_entry_t structure.
*
* To avoid looking up log level for given tag each time message is
* printed, this library caches pointers to tags. Because the suggested
* way of creating tags uses one 'TAG' constant per file, this caching
* should be effective. Cache is a binary min-heap of cached_tag_entry_t
* items, ordering is done on 'generation' member. In this context,
* generation is an integer which is incremented each time an operation
* with cache is performed. When cache is full, new item is inserted in
* place of an oldest item (that is, with smallest 'generation' value).
* After that, bubble-down operation is performed to fix ordering in the
* min-heap.
*
* The potential problem with wrap-around of cache generation counter is
* ignored for now. This will happen if someone happens to output more
* than 4 billion log entries, at which point wrap-around will not be
* the biggest problem.
*
*/
#ifndef BOOTLOADER_BUILD
#include <freertos/FreeRTOS.h>
#include <freertos/FreeRTOSConfig.h>
#include <freertos/task.h>
#include <freertos/semphr.h>
#endif
#include "esp_attr.h"
#include "xtensa/hal.h"
#include "soc/soc.h"
#include <stdbool.h>
#include <stdarg.h>
#include <string.h>
#include <stdlib.h>
#include <stdio.h>
#include <assert.h>
#include "esp_log.h"
#ifndef BOOTLOADER_BUILD
// Number of tags to be cached. Must be 2**n - 1, n >= 2.
#define TAG_CACHE_SIZE 31
// Maximum time to wait for the mutex in a logging statement.
#define MAX_MUTEX_WAIT_MS 10
#define MAX_MUTEX_WAIT_TICKS ((MAX_MUTEX_WAIT_MS + portTICK_PERIOD_MS - 1) / portTICK_PERIOD_MS)
// Uncomment this to enable consistency checks and cache statistics in this file.
// #define LOG_BUILTIN_CHECKS
typedef struct {
const char* tag;
uint32_t level : 3;
uint32_t generation : 29;
} cached_tag_entry_t;
typedef struct uncached_tag_entry_{
struct uncached_tag_entry_* next;
uint8_t level; // esp_log_level_t as uint8_t
char tag[0]; // beginning of a zero-terminated string
} uncached_tag_entry_t;
static esp_log_level_t s_log_default_level = ESP_LOG_VERBOSE;
static uncached_tag_entry_t* s_log_tags_head = NULL;
static uncached_tag_entry_t* s_log_tags_tail = NULL;
static cached_tag_entry_t s_log_cache[TAG_CACHE_SIZE];
static uint32_t s_log_cache_max_generation = 0;
static uint32_t s_log_cache_entry_count = 0;
static vprintf_like_t s_log_print_func = &vprintf;
static SemaphoreHandle_t s_log_mutex = NULL;
#ifdef LOG_BUILTIN_CHECKS
static uint32_t s_log_cache_misses = 0;
#endif
static inline bool get_cached_log_level(const char* tag, esp_log_level_t* level);
static inline bool get_uncached_log_level(const char* tag, esp_log_level_t* level);
static inline void add_to_cache(const char* tag, esp_log_level_t level);
static void heap_bubble_down(int index);
static inline void heap_swap(int i, int j);
static inline bool should_output(esp_log_level_t level_for_message, esp_log_level_t level_for_tag);
static inline void clear_log_level_list();
void esp_log_set_vprintf(vprintf_like_t func)
{
s_log_print_func = func;
}
void esp_log_level_set(const char* tag, esp_log_level_t level)
{
if (!s_log_mutex) {
s_log_mutex = xSemaphoreCreateMutex();
}
xSemaphoreTake(s_log_mutex, portMAX_DELAY);
// for wildcard tag, remove all linked list items and clear the cache
if (strcmp(tag, "*") == 0) {
s_log_default_level = level;
clear_log_level_list();
xSemaphoreGive(s_log_mutex);
return;
}
// allocate new linked list entry and append it to the endo of the list
size_t entry_size = offsetof(uncached_tag_entry_t, tag) + strlen(tag) + 1;
uncached_tag_entry_t* new_entry = (uncached_tag_entry_t*) malloc(entry_size);
if (!new_entry) {
xSemaphoreGive(s_log_mutex);
return;
}
new_entry->next = NULL;
new_entry->level = (uint8_t) level;
strcpy(new_entry->tag, tag);
if (s_log_tags_tail) {
s_log_tags_tail->next = new_entry;
}
s_log_tags_tail = new_entry;
if (!s_log_tags_head) {
s_log_tags_head = new_entry;
}
xSemaphoreGive(s_log_mutex);
}
void clear_log_level_list()
{
for (uncached_tag_entry_t* it = s_log_tags_head; it != NULL; ) {
uncached_tag_entry_t* next = it->next;
free(it);
it = next;
}
s_log_tags_tail = NULL;
s_log_tags_head = NULL;
s_log_cache_entry_count = 0;
s_log_cache_max_generation = 0;
#ifdef LOG_BUILTIN_CHECKS
s_log_cache_misses = 0;
#endif
}
void IRAM_ATTR esp_log_write(esp_log_level_t level,
const char* tag,
const char* format, ...)
{
if (!s_log_mutex) {
s_log_mutex = xSemaphoreCreateMutex();
}
if (xSemaphoreTake(s_log_mutex, MAX_MUTEX_WAIT_TICKS) == pdFALSE) {
return;
}
esp_log_level_t level_for_tag;
// Look for the tag in cache first, then in the linked list of all tags
if (!get_cached_log_level(tag, &level_for_tag)) {
if (!get_uncached_log_level(tag, &level_for_tag)) {
level_for_tag = s_log_default_level;
}
add_to_cache(tag, level_for_tag);
#ifdef LOG_BUILTIN_CHECKS
++s_log_cache_misses;
#endif
}
xSemaphoreGive(s_log_mutex);
if (!should_output(level, level_for_tag)) {
return;
}
va_list list;
va_start(list, format);
(*s_log_print_func)(format, list);
va_end(list);
}
static inline bool get_cached_log_level(const char* tag, esp_log_level_t* level)
{
// Look for `tag` in cache
int i;
for (i = 0; i < s_log_cache_entry_count; ++i) {
#ifdef LOG_BUILTIN_CHECKS
assert(i == 0 || s_log_cache[(i - 1) / 2].generation < s_log_cache[i].generation);
#endif
if (s_log_cache[i].tag == tag) {
break;
}
}
if (i == s_log_cache_entry_count) { // Not found in cache
return false;
}
// Return level from cache
*level = (esp_log_level_t) s_log_cache[i].level;
// If cache has been filled, start taking ordering into account
// (other options are: dynamically resize cache, add "dummy" entries
// to the cache; this option was chosen because code is much simpler,
// and the unfair behavior of cache will show it self at most once, when
// it has just been filled)
if (s_log_cache_entry_count == TAG_CACHE_SIZE) {
// Update item generation
s_log_cache[i].generation = s_log_cache_max_generation++;
// Restore heap ordering
heap_bubble_down(i);
}
return true;
}
static inline void add_to_cache(const char* tag, esp_log_level_t level)
{
uint32_t generation = s_log_cache_max_generation++;
// First consider the case when cache is not filled yet.
// In this case, just add new entry at the end.
// This happens to satisfy binary min-heap ordering.
if (s_log_cache_entry_count < TAG_CACHE_SIZE) {
s_log_cache[s_log_cache_entry_count] = (cached_tag_entry_t) {
.generation = generation,
.level = level,
.tag = tag
};
++s_log_cache_entry_count;
return;
}
// Cache is full, so we replace the oldest entry (which is at index 0
// because this is a min-heap) with the new one, and do bubble-down
// operation to restore min-heap ordering.
s_log_cache[0] = (cached_tag_entry_t) {
.tag = tag,
.level = level,
.generation = generation
};
heap_bubble_down(0);
}
static inline bool get_uncached_log_level(const char* tag, esp_log_level_t* level)
{
// Walk the linked list of all tags and see if given tag is present in the list.
// This is slow because tags are compared as strings.
for (uncached_tag_entry_t* it = s_log_tags_head; it != NULL; it = it->next) {
if (strcmp(tag, it->tag) == 0) {
*level = it->level;
return true;
}
}
return false;
}
static inline bool should_output(esp_log_level_t level_for_message, esp_log_level_t level_for_tag)
{
return level_for_message <= level_for_tag;
}
static void heap_bubble_down(int index)
{
while (index < TAG_CACHE_SIZE / 2) {
int left_index = index * 2 + 1;
int right_index = left_index + 1;
int next = (s_log_cache[left_index].generation < s_log_cache[right_index].generation) ? left_index : right_index;
heap_swap(index, next);
index = next;
}
}
static inline void heap_swap(int i, int j)
{
cached_tag_entry_t tmp = s_log_cache[i];
s_log_cache[i] = s_log_cache[j];
s_log_cache[j] = tmp;
}
#endif //BOOTLOADER_BUILD
inline IRAM_ATTR uint32_t esp_log_early_timestamp()
{
return xthal_get_ccount() / (CPU_CLK_FREQ_ROM / 1000);
}
#ifndef BOOTLOADER_BUILD
uint32_t IRAM_ATTR esp_log_timestamp()
{
if (xTaskGetSchedulerState() == taskSCHEDULER_NOT_STARTED) {
return esp_log_early_timestamp();
}
static uint32_t base = 0;
if (base == 0) {
base = esp_log_early_timestamp();
}
return base + xTaskGetTickCount() * (1000 / configTICK_RATE_HZ);
}
#else
uint32_t IRAM_ATTR esp_log_timestamp()
{
return esp_log_early_timestamp();
}
#endif //BOOTLOADER_BUILD