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/**
* Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
* SPDX-License-Identifier: Apache-2.0.
*/
#include <aws/common/log_channel.h>
#include <aws/common/condition_variable.h>
#include <aws/common/log_writer.h>
#include <aws/common/mutex.h>
#include <aws/common/string.h>
#include <aws/common/thread.h>
#include <stdio.h>
/*
* Basic channel implementations - synchronized foreground, synchronized background
*/
struct aws_log_foreground_channel {
struct aws_mutex sync;
};
static int s_foreground_channel_send(struct aws_log_channel *channel, struct aws_string *log_line) {
struct aws_log_foreground_channel *impl = (struct aws_log_foreground_channel *)channel->impl;
AWS_ASSERT(channel->writer->vtable->write);
aws_mutex_lock(&impl->sync);
(channel->writer->vtable->write)(channel->writer, log_line);
aws_mutex_unlock(&impl->sync);
/*
* send is considered a transfer of ownership. write is not a transfer of ownership.
* So it's always the channel's responsibility to clean up all log lines that enter
* it as soon as they are no longer needed.
*/
aws_string_destroy(log_line);
return AWS_OP_SUCCESS;
}
static void s_foreground_channel_clean_up(struct aws_log_channel *channel) {
struct aws_log_foreground_channel *impl = (struct aws_log_foreground_channel *)channel->impl;
aws_mutex_clean_up(&impl->sync);
aws_mem_release(channel->allocator, impl);
}
static struct aws_log_channel_vtable s_foreground_channel_vtable = {
.send = s_foreground_channel_send,
.clean_up = s_foreground_channel_clean_up,
};
int aws_log_channel_init_foreground(
struct aws_log_channel *channel,
struct aws_allocator *allocator,
struct aws_log_writer *writer) {
struct aws_log_foreground_channel *impl = aws_mem_calloc(allocator, 1, sizeof(struct aws_log_foreground_channel));
if (impl == NULL) {
return AWS_OP_ERR;
}
if (aws_mutex_init(&impl->sync)) {
aws_mem_release(allocator, impl);
return AWS_OP_ERR;
}
channel->vtable = &s_foreground_channel_vtable;
channel->allocator = allocator;
channel->writer = writer;
channel->impl = impl;
return AWS_OP_SUCCESS;
}
struct aws_log_background_channel {
struct aws_mutex sync;
struct aws_thread background_thread;
struct aws_array_list pending_log_lines;
struct aws_condition_variable pending_line_signal;
bool finished;
};
static int s_background_channel_send(struct aws_log_channel *channel, struct aws_string *log_line) {
struct aws_log_background_channel *impl = (struct aws_log_background_channel *)channel->impl;
aws_mutex_lock(&impl->sync);
aws_array_list_push_back(&impl->pending_log_lines, &log_line);
aws_condition_variable_notify_one(&impl->pending_line_signal);
aws_mutex_unlock(&impl->sync);
return AWS_OP_SUCCESS;
}
static void s_background_channel_clean_up(struct aws_log_channel *channel) {
struct aws_log_background_channel *impl = (struct aws_log_background_channel *)channel->impl;
aws_mutex_lock(&impl->sync);
impl->finished = true;
aws_condition_variable_notify_one(&impl->pending_line_signal);
aws_mutex_unlock(&impl->sync);
aws_thread_join(&impl->background_thread);
aws_thread_clean_up(&impl->background_thread);
aws_condition_variable_clean_up(&impl->pending_line_signal);
aws_array_list_clean_up(&impl->pending_log_lines);
aws_mutex_clean_up(&impl->sync);
aws_mem_release(channel->allocator, impl);
}
static struct aws_log_channel_vtable s_background_channel_vtable = {
.send = s_background_channel_send,
.clean_up = s_background_channel_clean_up,
};
static bool s_background_wait(void *context) {
struct aws_log_background_channel *impl = (struct aws_log_background_channel *)context;
/*
* Condition variable predicates are checked under mutex protection
*/
return impl->finished || aws_array_list_length(&impl->pending_log_lines) > 0;
}
static void s_background_thread_writer(void *thread_data) {
(void)thread_data;
struct aws_log_channel *channel = (struct aws_log_channel *)thread_data;
AWS_ASSERT(channel->writer->vtable->write);
struct aws_log_background_channel *impl = (struct aws_log_background_channel *)channel->impl;
struct aws_array_list log_lines;
AWS_FATAL_ASSERT(aws_array_list_init_dynamic(&log_lines, channel->allocator, 10, sizeof(struct aws_string *)) == 0);
while (true) {
aws_mutex_lock(&impl->sync);
aws_condition_variable_wait_pred(&impl->pending_line_signal, &impl->sync, s_background_wait, impl);
size_t line_count = aws_array_list_length(&impl->pending_log_lines);
bool finished = impl->finished;
if (line_count == 0) {
aws_mutex_unlock(&impl->sync);
if (finished) {
break;
}
continue;
}
aws_array_list_swap_contents(&impl->pending_log_lines, &log_lines);
aws_mutex_unlock(&impl->sync);
/*
* Consider copying these into a page-sized stack buffer (string) and then making the write calls
* against it rather than the individual strings. Might be a savings when > 1 lines (cut down on
* write calls).
*/
for (size_t i = 0; i < line_count; ++i) {
struct aws_string *log_line = NULL;
AWS_FATAL_ASSERT(aws_array_list_get_at(&log_lines, &log_line, i) == AWS_OP_SUCCESS);
(channel->writer->vtable->write)(channel->writer, log_line);
/*
* send is considered a transfer of ownership. write is not a transfer of ownership.
* So it's always the channel's responsibility to clean up all log lines that enter
* it as soon as they are no longer needed.
*/
aws_string_destroy(log_line);
}
aws_array_list_clear(&log_lines);
}
aws_array_list_clean_up(&log_lines);
}
int aws_log_channel_init_background(
struct aws_log_channel *channel,
struct aws_allocator *allocator,
struct aws_log_writer *writer) {
struct aws_log_background_channel *impl = aws_mem_calloc(allocator, 1, sizeof(struct aws_log_background_channel));
if (impl == NULL) {
return AWS_OP_ERR;
}
impl->finished = false;
if (aws_mutex_init(&impl->sync)) {
goto clean_up_sync_init_fail;
}
if (aws_array_list_init_dynamic(&impl->pending_log_lines, allocator, 10, sizeof(struct aws_string *))) {
goto clean_up_pending_log_lines_init_fail;
}
if (aws_condition_variable_init(&impl->pending_line_signal)) {
goto clean_up_pending_line_signal_init_fail;
}
if (aws_thread_init(&impl->background_thread, allocator)) {
goto clean_up_background_thread_init_fail;
}
channel->vtable = &s_background_channel_vtable;
channel->allocator = allocator;
channel->impl = impl;
channel->writer = writer;
/*
* Logging thread should need very little stack, but let's defer this to later
*/
struct aws_thread_options thread_options = {.stack_size = 0};
if (aws_thread_launch(&impl->background_thread, s_background_thread_writer, channel, &thread_options) ==
AWS_OP_SUCCESS) {
return AWS_OP_SUCCESS;
}
aws_thread_clean_up(&impl->background_thread);
clean_up_background_thread_init_fail:
aws_condition_variable_clean_up(&impl->pending_line_signal);
clean_up_pending_line_signal_init_fail:
aws_array_list_clean_up(&impl->pending_log_lines);
clean_up_pending_log_lines_init_fail:
aws_mutex_clean_up(&impl->sync);
clean_up_sync_init_fail:
aws_mem_release(allocator, impl);
return AWS_OP_ERR;
}
void aws_log_channel_clean_up(struct aws_log_channel *channel) {
AWS_ASSERT(channel->vtable->clean_up);
(channel->vtable->clean_up)(channel);
}
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