#include <sys/types.h>
#include <unistd.h> 
#include <stdio.h> 
#include <stdlib.h>
#include <assert.h>
#include <errno.h>
#include <sys/time.h>
#include <time.h>
#include <string.h>
#include <curl/curl.h>

#include "tango_cache_transfer.h"
#include "tango_cache_xml.h"
#include "tango_cache_tools.h"

//response body很短或不关心时
size_t curl_response_any_cb(void *ptr, size_t size, size_t count, void *userp)
{
	return size*count;
}

static size_t curl_put_multipart_header_cb(void *ptr, size_t size, size_t count, void *userp)
{
	struct tango_cache_ctx *ctx = (struct tango_cache_ctx *)userp;
	size_t totallen = size*count;
	char *start = (char *)ptr, *end = start + totallen;
	struct multipart_etag_list *etag;

	if(!strncmp(start, "Etag:", totallen>5?5:totallen))
	{
		start += 5; end -= 1; totallen -= 5;
		while(totallen>0 && (*start==' ')) {start++; totallen--;}
		while(totallen>0 && (*end=='\r'||*end=='\n')) {end--; totallen--;}
		if(totallen > 0)
		{
			etag = (struct multipart_etag_list *)malloc(sizeof(struct multipart_etag_list));
			totallen = end - start + 1;
			etag->etag = (char *)malloc(totallen + 1);
			etag->part_number = ctx->put.part_index;
			memcpy(etag->etag, start, totallen);
			*(etag->etag + totallen) = '\0';
			TAILQ_INSERT_TAIL(&ctx->put.etag_head, etag, node);
		}
	}
	
	return size*count;
}

static size_t curl_put_once_send_cb(void *ptr, size_t size, size_t count, void *userp)
{
	size_t len;
	struct tango_cache_ctx *ctx = (struct tango_cache_ctx *)userp;

	if(size==0 || count==0 || ctx->response.len>=ctx->response.size)
	{
		return 0; //不一定调用
	}

	len = ctx->response.size - ctx->response.len; //剩余待上传的长度
	if(len > size * count)
	{
		len = size * count;
	}

	memcpy(ptr, ctx->response.buff + ctx->response.len, len);
	ctx->response.len += len;

	if(ctx->response.len >= ctx->response.size)
	{
		ctx->instance->statistic.memory_used -= ctx->response.size; //未使用cache buffer，自己计算内存增减
		easy_string_destroy(&ctx->response);
	}
	return len;
}

static size_t curl_put_multipart_send_cb(void *ptr, size_t size, size_t count, void *userp)
{
	size_t len, space=size*count, send_len;
	struct tango_cache_ctx *ctx = (struct tango_cache_ctx *)userp;

	if(size==0 || count==0 || ctx->put.upload_offset>=ctx->put.upload_length)
	{
		return 0;
	}

	len = ctx->put.upload_length - ctx->put.upload_offset;
	if(len > space)
	{
		len = space;
	}
	send_len = evbuffer_remove(ctx->put.evbuf, ptr, len);
	assert(send_len>0);
	ctx->put.upload_offset += send_len;
	ctx->instance->statistic.memory_used -= send_len;
	
	return send_len;
}

//return value: <0:fail; =0: not exec; >0: OK
static int http_put_bodypart_request_evbuf(struct tango_cache_ctx *ctx, bool full)
{
	CURLMcode rc;
	char minio_url[256];

	if(NULL == (ctx->curl=curl_easy_init())) 
	{
		return -1;
	}

	ctx->put.upload_offset = 0;
	if(full)
	{
		snprintf(minio_url, 256, "http://%s/%s/%s", ctx->hostaddr, ctx->instance->bucketname, ctx->object_key);
	}
	else
	{
		snprintf(minio_url, 256, "http://%s/%s/%s?partNumber=%d&uploadId=%s", ctx->hostaddr, ctx->instance->bucketname, ctx->object_key, ++ctx->put.part_index, ctx->put.uploadID);
		curl_easy_setopt(ctx->curl, CURLOPT_HEADERFUNCTION, curl_put_multipart_header_cb);
		curl_easy_setopt(ctx->curl, CURLOPT_HEADERDATA, ctx);
	}
	curl_easy_setopt(ctx->curl, CURLOPT_URL, minio_url);
	curl_easy_setopt(ctx->curl, CURLOPT_USERAGENT, "aws-sdk-cpp/1.5.24 Linux/3.10.0-327.el7.x86_64 x86_64 pangu_cache");
	curl_easy_setopt(ctx->curl, CURLOPT_NOSIGNAL, 1L);
	curl_easy_setopt(ctx->curl, CURLOPT_WRITEFUNCTION, curl_response_any_cb);
	curl_easy_setopt(ctx->curl, CURLOPT_WRITEDATA, ctx);
	curl_easy_setopt(ctx->curl, CURLOPT_ERRORBUFFER, ctx->error);
	curl_easy_setopt(ctx->curl, CURLOPT_PRIVATE, ctx);
	curl_easy_setopt(ctx->curl, CURLOPT_FOLLOWLOCATION, 1L);
	curl_easy_setopt(ctx->curl, CURLOPT_CONNECTTIMEOUT_MS, 500L); 
	curl_easy_setopt(ctx->curl, CURLOPT_HTTPHEADER, ctx->headers);
	curl_easy_setopt(ctx->curl, CURLOPT_LOW_SPEED_TIME, 2L);
	curl_easy_setopt(ctx->curl, CURLOPT_LOW_SPEED_LIMIT, 100L);

	curl_easy_setopt(ctx->curl, CURLOPT_UPLOAD, 1L);
	curl_easy_setopt(ctx->curl, CURLOPT_INFILESIZE, ctx->put.upload_length);
	curl_easy_setopt(ctx->curl, CURLOPT_READFUNCTION, curl_put_multipart_send_cb);
	curl_easy_setopt(ctx->curl, CURLOPT_READDATA, ctx);

	rc = curl_multi_add_handle(ctx->instance->multi_hd, ctx->curl);
	assert(rc==CURLM_OK);
	return 1;
}

static size_t curl_write_uploadID_cb(void *ptr, size_t size, size_t count, void *userp)
{
	struct tango_cache_ctx *ctx = (struct tango_cache_ctx *)userp;
	struct easy_string *estr = &ctx->response;
	CURLcode code;

	if(ctx->fail_state)
	{
	   return size*count;
	}

	if(ctx->res_code == 0)
	{
		code = curl_easy_getinfo(ctx->curl, CURLINFO_RESPONSE_CODE, &ctx->res_code);
		if(code != CURLE_OK || ctx->res_code!=200L)
		{
			ctx->fail_state = true;
			ctx->error_code = CACHE_ERR_CURL;
			if(code != CURLE_OK) MESA_HANDLE_RUNTIME_LOGV2(ctx->instance->runtime_log, RLOG_LV_DEBUG, "%s", ctx->error);
			return size*count;
		}
	}

	easy_string_savedata(estr, (const char*)ptr, size*count);
	return size*count;
}

int curl_get_minio_uploadID(struct tango_cache_ctx *ctx)
{
	CURLMcode rc;
	char minio_url[256];
	
	if(NULL == (ctx->curl=curl_easy_init())) 
	{
		free(ctx);
		return -1;
	}
	
	snprintf(minio_url, 256, "http://%s/%s/%s?uploads", ctx->hostaddr, ctx->instance->bucketname, ctx->object_key);
	curl_easy_setopt(ctx->curl, CURLOPT_POST, 1L);
	curl_easy_setopt(ctx->curl, CURLOPT_URL, minio_url);
	curl_easy_setopt(ctx->curl, CURLOPT_USERAGENT, "aws-sdk-cpp/1.5.24 Linux/3.10.0-327.el7.x86_64 x86_64 pangu_cache");
	curl_easy_setopt(ctx->curl, CURLOPT_NOSIGNAL,1L);
	curl_easy_setopt(ctx->curl, CURLOPT_WRITEFUNCTION, curl_write_uploadID_cb);
	curl_easy_setopt(ctx->curl, CURLOPT_WRITEDATA, ctx);
	curl_easy_setopt(ctx->curl, CURLOPT_ERRORBUFFER, ctx->error);
	curl_easy_setopt(ctx->curl, CURLOPT_PRIVATE, ctx);
	curl_easy_setopt(ctx->curl, CURLOPT_FOLLOWLOCATION, 1L);
	curl_easy_setopt(ctx->curl, CURLOPT_CONNECTTIMEOUT_MS, 500L); 
	curl_easy_setopt(ctx->curl, CURLOPT_HTTPHEADER, ctx->headers);
	curl_easy_setopt(ctx->curl, CURLOPT_LOW_SPEED_TIME, 2L);
	curl_easy_setopt(ctx->curl, CURLOPT_LOW_SPEED_LIMIT, 100L);

	rc = curl_multi_add_handle(ctx->instance->multi_hd, ctx->curl);
	assert(rc==CURLM_OK);
	return 1;
}

int cache_delete_minio_object(struct tango_cache_ctx *ctx)
{
	CURLMcode rc;
	char minio_url[256];

	ctx->instance->statistic.del_recv_num += 1;
	if(NULL == (ctx->curl=curl_easy_init())) 
	{
		return 0;
	}

	snprintf(minio_url, 256, "http://%s/%s/%s", ctx->hostaddr, ctx->instance->bucketname, ctx->object_key);
	curl_easy_setopt(ctx->curl, CURLOPT_CUSTOMREQUEST, "DELETE");
	curl_easy_setopt(ctx->curl, CURLOPT_URL, minio_url);
	curl_easy_setopt(ctx->curl, CURLOPT_USERAGENT, "aws-sdk-cpp/1.5.24 Linux/3.10.0-327.el7.x86_64 x86_64 pangu_cache");
	curl_easy_setopt(ctx->curl, CURLOPT_NOSIGNAL, 1L);
	curl_easy_setopt(ctx->curl, CURLOPT_WRITEFUNCTION, curl_response_any_cb);
	curl_easy_setopt(ctx->curl, CURLOPT_WRITEDATA, ctx);
	curl_easy_setopt(ctx->curl, CURLOPT_ERRORBUFFER, ctx->error);
	curl_easy_setopt(ctx->curl, CURLOPT_PRIVATE, ctx);
	curl_easy_setopt(ctx->curl, CURLOPT_FOLLOWLOCATION, 1L);
	curl_easy_setopt(ctx->curl, CURLOPT_CONNECTTIMEOUT_MS, 500L); 

	rc = curl_multi_add_handle(ctx->instance->multi_hd, ctx->curl);
	assert(rc==CURLM_OK);
	return 1;
}

//return value: true-成功添加事件；false-未添加事件
bool cache_cancel_upload_minio(struct tango_cache_ctx *ctx)
{
	CURLMcode rc;
	char minio_url[256];

	if(NULL == (ctx->curl=curl_easy_init())) 
	{
		return false;
	}

	snprintf(minio_url, 256, "http://%s/%s/%s?uploadId=%s", ctx->hostaddr, ctx->instance->bucketname, ctx->object_key, ctx->put.uploadID);
	curl_easy_setopt(ctx->curl, CURLOPT_CUSTOMREQUEST, "DELETE");
	curl_easy_setopt(ctx->curl, CURLOPT_URL, minio_url);
	curl_easy_setopt(ctx->curl, CURLOPT_USERAGENT, "aws-sdk-cpp/1.5.24 Linux/3.10.0-327.el7.x86_64 x86_64 pangu_cache");
	curl_easy_setopt(ctx->curl, CURLOPT_NOSIGNAL, 1L);
	curl_easy_setopt(ctx->curl, CURLOPT_WRITEFUNCTION, curl_response_any_cb);
	curl_easy_setopt(ctx->curl, CURLOPT_WRITEDATA, ctx);
	curl_easy_setopt(ctx->curl, CURLOPT_ERRORBUFFER, ctx->error);
	curl_easy_setopt(ctx->curl, CURLOPT_PRIVATE, ctx);
	curl_easy_setopt(ctx->curl, CURLOPT_FOLLOWLOCATION, 1L);
	curl_easy_setopt(ctx->curl, CURLOPT_CONNECTTIMEOUT_MS, 500L); 

	rc = curl_multi_add_handle(ctx->instance->multi_hd, ctx->curl);
	assert(rc==CURLM_OK);
	return true;
}

//return value: true-成功添加事件；false-未添加事件
bool cache_kick_combine_minio(struct tango_cache_ctx *ctx)
{
	int len=0;
	CURLMcode rc;
	char minio_url[256];
	
	if(NULL == (ctx->curl=curl_easy_init())) 
	{
		return false;
	}
	construct_complete_xml(ctx, &ctx->put.combine_xml, &len);
	
	snprintf(minio_url, 256, "http://%s/%s/%s?uploadId=%s", ctx->hostaddr, ctx->instance->bucketname, ctx->object_key, ctx->put.uploadID);
	curl_easy_setopt(ctx->curl, CURLOPT_POST, 1L);
	curl_easy_setopt(ctx->curl, CURLOPT_URL, minio_url);
	curl_easy_setopt(ctx->curl, CURLOPT_USERAGENT, "aws-sdk-cpp/1.5.24 Linux/3.10.0-327.el7.x86_64 x86_64 pangu_cache");
	curl_easy_setopt(ctx->curl, CURLOPT_NOSIGNAL,1L);
	curl_easy_setopt(ctx->curl, CURLOPT_WRITEFUNCTION, curl_response_any_cb);
	curl_easy_setopt(ctx->curl, CURLOPT_WRITEDATA, ctx);
	curl_easy_setopt(ctx->curl, CURLOPT_ERRORBUFFER, ctx->error);
	curl_easy_setopt(ctx->curl, CURLOPT_PRIVATE, ctx);
	curl_easy_setopt(ctx->curl, CURLOPT_FOLLOWLOCATION, 1L);
	curl_easy_setopt(ctx->curl, CURLOPT_CONNECTTIMEOUT_MS, 500L);
	
	curl_easy_setopt(ctx->curl, CURLOPT_POSTFIELDS, ctx->put.combine_xml);
	curl_easy_setopt(ctx->curl, CURLOPT_POSTFIELDSIZE, len); //填充Content-Length

	if(ctx->headers != NULL)
	{
		curl_slist_free_all(ctx->headers);
		ctx->headers = NULL;
	}
	ctx->headers = curl_slist_append(ctx->headers, "Content-Type: application/xml");
	curl_easy_setopt(ctx->curl, CURLOPT_HTTPHEADER, ctx->headers);

	rc = curl_multi_add_handle(ctx->instance->multi_hd, ctx->curl);
	assert(rc==CURLM_OK);
	return true;
}

//return value: true-成功添加事件；false-未添加事件
bool cache_kick_upload_minio_multipart(struct tango_cache_ctx *ctx, size_t block_len)
{
	int ret = 1;

	switch(ctx->put.state)
	{
		case PUT_STATE_START:
			ctx->put.state = PUT_STATE_WAIT_START;
			ret = curl_get_minio_uploadID(ctx);
			break;

		case PUT_STATE_PART:
			if(ctx->curl == NULL)
			{
				ctx->put.upload_length = block_len;
				ret = http_put_bodypart_request_evbuf(ctx, false);
			}
			break;
			
		default: break;//nothing to do
	}
	
	if(ret <= 0)
	{
		ctx->fail_state = true;
		ctx->error_code = CACHE_ERR_CURL;
		return false;
	}
	return true;
}

int http_put_complete_part_evbuf(struct tango_cache_ctx *ctx)
{
	int ret=0;
	
	ctx->put.state = PUT_STATE_END;
	ctx->put.upload_length = evbuffer_get_length(ctx->put.evbuf);
	if(ctx->put.upload_length > 0)
	{
		ret = http_put_bodypart_request_evbuf(ctx, true);
		if(ret <= 0)
		{
			ctx->fail_state = true;
			ctx->error_code = CACHE_ERR_CURL;
			tango_cache_ctx_destroy(ctx);
		}
	}
	else
	{
		tango_cache_ctx_destroy(ctx);
	}

	return ret;
}

int cache_kick_upload_minio_end(struct tango_cache_ctx *ctx)
{
	int ret = 0;

	ctx->put.close_state = true;//仅设置状态，并非真正关闭；内部状态机轮转结束后再关闭
	if(ctx->fail_state)
	{
		tango_cache_ctx_destroy(ctx);
		return 0;
	}
	
	switch(ctx->put.state)
	{
		case PUT_STATE_START:
			http_put_complete_part_evbuf(ctx);
			break;

		case PUT_STATE_PART:
			if(ctx->curl == NULL)
			{
				ctx->put.upload_length = evbuffer_get_length(ctx->put.evbuf);
				if(ctx->put.upload_length == 0)
				{
					if(cache_kick_combine_minio(ctx))
					{
						ctx->put.state = PUT_STATE_END;
					}
					else
					{
						ctx->fail_state = true;
						ctx->error_code = CACHE_ERR_CURL;
						tango_cache_ctx_destroy(ctx);
					}
				}
				else
				{
					ret = http_put_bodypart_request_evbuf(ctx, false);
					if(ret <= 0)
					{
						ctx->fail_state = true;
						ctx->error_code = CACHE_ERR_CURL;
						if(cache_cancel_upload_minio(ctx))
						{
							ctx->put.state = PUT_STATE_CANCEL;
						}
						else
						{
							tango_cache_ctx_destroy(ctx);
						}
					}
				}
			}
			break;
			
		case PUT_STATE_END: assert(0); //用户主动调用end时不可能处于此状态
		case PUT_STATE_WAIT_START: //此时未获取到uploadId，所以无法触发上传
		default: break;
	}

	return ret;
}

void tango_cache_curl_put_done(struct tango_cache_ctx *ctx, CURLcode res, long res_code)
{
	switch(ctx->put.state)
	{
		case PUT_STATE_WAIT_START:
			if(res!=CURLE_OK||res_code!=200L|| ctx->fail_state || !parse_uploadID_xml(ctx->response.buff, ctx->response.len, &ctx->put.uploadID))
			{
				easy_string_destroy(&ctx->response);
				ctx->error_code = CACHE_ERR_CURL;
				ctx->fail_state = true;
				if(res != CURLE_OK) MESA_HANDLE_RUNTIME_LOGV2(ctx->instance->runtime_log, RLOG_LV_DEBUG, "%s", ctx->error);
				if(ctx->put.close_state)
				{
					tango_cache_ctx_destroy(ctx);
				}
			}
			else
			{
				easy_string_destroy(&ctx->response);
				ctx->put.state = PUT_STATE_PART;
				if(ctx->put.close_state)
				{
					cache_kick_upload_minio_end(ctx);
				}
				else
				{
					size_t upload_length = evbuffer_get_length(ctx->put.evbuf);
					if(upload_length >= ctx->instance->upload_block_size)
					{
						cache_kick_upload_minio_multipart(ctx, upload_length);
					}
				}
			}
			break;

		case PUT_STATE_PART:
			if(res != CURLE_OK || res_code!=200L)
			{
				ctx->fail_state = true;
				ctx->error_code = CACHE_ERR_CURL;
				if(res != CURLE_OK) MESA_HANDLE_RUNTIME_LOGV2(ctx->instance->runtime_log, RLOG_LV_DEBUG, "%s", ctx->error);
			}
			if(ctx->fail_state)
			{
				if(cache_cancel_upload_minio(ctx))
				{
					ctx->put.state = PUT_STATE_CANCEL;
				}
				else if(ctx->put.close_state)
				{
					tango_cache_ctx_destroy(ctx);
				}
			}
			else if(ctx->put.close_state)
			{
				cache_kick_upload_minio_end(ctx);
			}
			else
			{
				size_t upload_length = evbuffer_get_length(ctx->put.evbuf);
				if(upload_length >= ctx->instance->upload_block_size)
				{
					cache_kick_upload_minio_multipart(ctx, upload_length);
				}
			}
			break;
			
		case PUT_STATE_CANCEL: //等待关闭
			if(ctx->put.close_state)
			{
				tango_cache_ctx_destroy(ctx);
			}
			break;
			
		case PUT_STATE_END:
			if(res != CURLE_OK || res_code!=200L)
			{
				ctx->fail_state = true;
				ctx->error_code = CACHE_ERR_CURL;
				if(res != CURLE_OK) MESA_HANDLE_RUNTIME_LOGV2(ctx->instance->runtime_log, RLOG_LV_DEBUG, "%s", ctx->error);
			}
			tango_cache_ctx_destroy(ctx);
			break;
		default: break;
	}
}

int tango_cache_upload_once_start_data(struct tango_cache_ctx *ctx, enum PUT_MEMORY_COPY_WAY way, const char *data, size_t size)
{
	CURLMcode rc;
	char minio_url[256];

	ctx->instance->statistic.put_recv_num += 1;
	ctx->instance->error_code = CACHE_OK;
	if(NULL == (ctx->curl=curl_easy_init())) 
	{
		tango_cache_ctx_destroy(ctx);
		if(way == PUT_MEM_FREE)
		{
			free((void *)data);
		}
		return -1;
	}
	ctx->put.state = PUT_STATE_END;

	snprintf(minio_url, 256, "http://%s/%s/%s", ctx->hostaddr, ctx->instance->bucketname, ctx->object_key);
	curl_easy_setopt(ctx->curl, CURLOPT_URL, minio_url);
	curl_easy_setopt(ctx->curl, CURLOPT_USERAGENT, "aws-sdk-cpp/1.5.24 Linux/3.10.0-327.el7.x86_64 x86_64 pangu_cache");
	curl_easy_setopt(ctx->curl, CURLOPT_NOSIGNAL, 1L);
	curl_easy_setopt(ctx->curl, CURLOPT_WRITEFUNCTION, curl_response_any_cb);
	curl_easy_setopt(ctx->curl, CURLOPT_WRITEDATA, ctx);
	curl_easy_setopt(ctx->curl, CURLOPT_ERRORBUFFER, ctx->error);
	curl_easy_setopt(ctx->curl, CURLOPT_PRIVATE, ctx);
	curl_easy_setopt(ctx->curl, CURLOPT_FOLLOWLOCATION, 1L);
	curl_easy_setopt(ctx->curl, CURLOPT_CONNECTTIMEOUT_MS, 500L); 
	curl_easy_setopt(ctx->curl, CURLOPT_HTTPHEADER, ctx->headers);
	curl_easy_setopt(ctx->curl, CURLOPT_LOW_SPEED_TIME, 2L);
	curl_easy_setopt(ctx->curl, CURLOPT_LOW_SPEED_LIMIT, 100L);

	if(way == PUT_MEM_COPY)
	{
		ctx->response.buff = (char *)malloc(size);
		memcpy(ctx->response.buff, data, size);
	}
	else
	{
		ctx->response.buff = (char *)data;
	}
	ctx->response.size = size;
	ctx->response.len = 0;
	ctx->instance->statistic.memory_used += size;
	curl_easy_setopt(ctx->curl, CURLOPT_UPLOAD, 1L);
	curl_easy_setopt(ctx->curl, CURLOPT_INFILESIZE, ctx->response.size);
	curl_easy_setopt(ctx->curl, CURLOPT_READFUNCTION, curl_put_once_send_cb);
	curl_easy_setopt(ctx->curl, CURLOPT_READDATA, ctx);

	rc = curl_multi_add_handle(ctx->instance->multi_hd, ctx->curl);
	assert(rc==CURLM_OK);
	return 0;
}

int tango_cache_upload_once_start_evbuf(struct tango_cache_ctx *ctx, enum EVBUFFER_COPY_WAY way, struct evbuffer *evbuf)
{
	size_t size;

	ctx->instance->statistic.put_recv_num += 1;
	ctx->instance->error_code = CACHE_OK;

	size = evbuffer_get_length(evbuf);
	if(way == EVBUFFER_MOVE)
	{
		if(evbuffer_add_buffer(ctx->put.evbuf, evbuf))
		{
			return -1;
		}
	}
	else
	{
		if(evbuffer_add_buffer_reference(ctx->put.evbuf, evbuf))
		{
			return -1;
		}
	}
	ctx->instance->statistic.memory_used += size;

	return http_put_complete_part_evbuf(ctx);
}

void tango_cache_curl_del_done(struct tango_cache_ctx *ctx, CURLcode res, long res_code)
{
	if(res!=CURLE_OK || (res_code!=204L && res_code!=200L ))
	{
		ctx->fail_state = true;
	}
	tango_cache_ctx_destroy(ctx);
}

void tango_cache_curl_get_done(struct tango_cache_ctx *ctx, CURLcode res, long res_code)
{
	switch(ctx->get.state)
	{
		case GET_STATE_START:
			if(!ctx->fail_state)
			{
				if(res!=CURLE_OK || res_code!=200L)
				{
					ctx->error_code = (res!=CURLE_OK)?CACHE_ERR_CURL:CACHE_CACHE_MISS;
					promise_failed(future_to_promise(ctx->future), FUTURE_ERROR_CANCEL, ctx->error);
				}
				else
				{
					promise_success(future_to_promise(ctx->future), NULL);
				}
			}
			tango_cache_ctx_destroy(ctx);
			break;
			
		case GET_STATE_DELETE:
			if(cache_delete_minio_object(ctx))
			{
				ctx->get.state = GET_STATE_END;
			}
			else
			{
				tango_cache_ctx_destroy(ctx);
			}
			break;
			
		case GET_STATE_END:
			tango_cache_ctx_destroy(ctx);
			break;
		default: assert(0);break;
	}
}

static size_t curl_get_response_body_cb(void *ptr, size_t size, size_t count, void *userp)
{
	struct tango_cache_ctx *ctx = (struct tango_cache_ctx *)userp;
	struct tango_cache_result result;

	if(ctx->fail_state || ctx->get.state==GET_STATE_DELETE)
	{
		return size*count;
	}
	
	if(ctx->get.need_hdrs!=RESPONSE_HDR_ALL) //无Expires时
	{
		ctx->fail_state = true;
		ctx->error_code = CACHE_ERR_CURL;
		ctx->get.state	= GET_STATE_DELETE;
		promise_failed(future_to_promise(ctx->future), FUTURE_ERROR_CANCEL, "cache Expires or x-amz-meta-lm not found");
		return size*count;
	}

	if(ctx->get.response_tag.len > 0)
	{
		result.data_frag = ctx->get.response_tag.buff;
		result.size = ctx->get.response_tag.len;
		result.type = RESULT_TYPE_USERTAG;
		promise_success(future_to_promise(ctx->future), &result);
		easy_string_destroy(&ctx->get.response_tag);
	}
	if(ctx->response.len > 0)
	{
		result.data_frag = ctx->response.buff;
		result.size = ctx->response.len;
		result.type = RESULT_TYPE_HEADER;
		promise_success(future_to_promise(ctx->future), &result);
		easy_string_destroy(&ctx->response);
	}
	result.data_frag = ptr;
	result.size = size * count;
	result.type = RESULT_TYPE_BODY;
	promise_success(future_to_promise(ctx->future), &result);
	return size*count;
}

static bool check_expires_header(struct tango_cache_ctx *ctx, const char *expires_val, size_t len)
{
	time_t time_gmt;

	ctx->get.expires = expires_hdr2timestamp(expires_val, len);
	time_gmt = get_gmtime_timestamp(time(NULL));
	
	if(time_gmt > ctx->get.expires) //缓存失效；TODO relative_age的含义是啥
	{
		ctx->fail_state = true;
		ctx->error_code = CACHE_TIMEOUT;
		ctx->get.state  = GET_STATE_DELETE; //缓存失效时在下载完毕时触发删除动作
		easy_string_destroy(&ctx->response);
		promise_failed(future_to_promise(ctx->future), FUTURE_ERROR_CANCEL, "cache not fresh");
		return false;
	}
	return true;
}

static bool check_fresh_header(struct tango_cache_ctx *ctx)
{
	time_t now_gmt;

	if(ctx->get.need_hdrs != RESPONSE_HDR_ALL)
		return true;

	now_gmt = get_gmtime_timestamp(time(NULL));
	if(ctx->get.last_modify+ctx->get.max_age > now_gmt || now_gmt+ctx->get.min_fresh>ctx->get.expires)
	{
		ctx->fail_state = true;
		ctx->error_code = CACHE_TIMEOUT;
		easy_string_destroy(&ctx->response);
		promise_failed(future_to_promise(ctx->future), FUTURE_ERROR_CANCEL, "cache not fresh");
		return false;
	}
	return true;
}

static bool check_get_result_code(struct tango_cache_ctx *ctx)
{
	CURLcode code;

	code = curl_easy_getinfo(ctx->curl, CURLINFO_RESPONSE_CODE, &ctx->res_code);
	if(code != CURLE_OK || ctx->res_code!=200L)
	{
		ctx->fail_state = true;
		ctx->error_code = (code!=CURLE_OK)?CACHE_ERR_CURL:CACHE_CACHE_MISS;
		promise_failed(future_to_promise(ctx->future), FUTURE_ERROR_CANCEL, (code!=CURLE_OK)?ctx->error:"cache not hit");
		return false;
	}
	return true;
}

static size_t curl_get_response_header_cb(void *ptr, size_t size, size_t count, void *userp)
{
	struct tango_cache_ctx *ctx = (struct tango_cache_ctx *)userp;
	char *start=(char *)ptr, *pos_colon;
	size_t raw_len = size*count, hdrlen=size*count;
	char usertag[2048];
	size_t datalen;

	if(ctx->fail_state || ctx->get.state==GET_STATE_DELETE)
	{
		return raw_len;
	}
	if(ctx->res_code==0 && !check_get_result_code(ctx)) //首次应答时先看应答码是否是200
	{
		return raw_len;
	}
	pos_colon = (char*)memchr(start, ':', raw_len);
	if(pos_colon == NULL)
	{
		return raw_len;
	}
	
	datalen = pos_colon - start;
	switch(datalen)
	{
		case 7:
			if(strcmp_one_word_mesa_equal_len("expires", "EXPIRES", start, 7))
			{
				ctx->get.need_hdrs |= RESPONSE_HDR_EXPIRES;
				if(!check_expires_header(ctx, pos_colon + 1, raw_len - datalen - 1) || !check_fresh_header(ctx))
				{
					return raw_len;
				}
			}
			break;
		case 13:
			if(strcmp_one_word_mesa_equal_len("x-amz-meta-lm", "X-AMZ-META-LM", start, 13))
			{
				ctx->get.need_hdrs |= RESPONSE_HDR_LAST_MOD;
				sscanf(pos_colon+1, "%lu", &ctx->get.last_modify);
				if(!check_fresh_header(ctx))
				{
					return raw_len;
				}
			}
			break;
		case 15:
			if(strcmp_one_word_mesa_equal_len("x-amz-meta-user", "X-AMZ-META-USER", start, 15))
			{
				if((hdrlen = Base64_DecodeBlock((unsigned char*)pos_colon+1, raw_len-datalen-1, (unsigned char*)usertag, 2048))>0)
				{
					easy_string_savedata(&ctx->get.response_tag, usertag, hdrlen);
				}
			}
			break;
		case 11: if(strcmp_one_word_mesa_equal_len("content-md5", "CONTENT-MD5", start, 11)) easy_string_savedata(&ctx->response, (const char*)ptr, raw_len); break;
		case 12: if(strcmp_one_word_mesa_equal_len("content-type", "CONTENT-TYPE", start, 12)) easy_string_savedata(&ctx->response, (const char*)ptr, raw_len); break;
		case 14: if(strcmp_one_word_mesa_equal_len("content-length", "CONTENT-LENGTH", start, 14)) easy_string_savedata(&ctx->response, (const char*)ptr, raw_len); break;
		case 16: if(strcmp_one_word_mesa_equal_len("content-encoding", "CONTENT-ENCODING", start, 16)) easy_string_savedata(&ctx->response, (const char*)ptr, raw_len); break;
		case 19: if(strcmp_one_word_mesa_equal_len("content-disposition", "CONTENT-DISPOSITION", start, 19)) easy_string_savedata(&ctx->response, (const char*)ptr, raw_len); break;
		default: break;
	}
	return raw_len;
}

int tango_cache_fetch_start(struct tango_cache_ctx *ctx)
{	
	CURLMcode rc;
	char minio_url[256];

	ctx->instance->statistic.get_recv_num += 1;
	if(NULL == (ctx->curl=curl_easy_init())) 
	{
		tango_cache_ctx_destroy(ctx);
		return -1;
	}

	snprintf(minio_url, 256, "http://%s/%s/%s", ctx->hostaddr, ctx->instance->bucketname, ctx->object_key);
	curl_easy_setopt(ctx->curl, CURLOPT_URL, minio_url);
	curl_easy_setopt(ctx->curl, CURLOPT_USERAGENT, "aws-sdk-cpp/1.5.24 Linux/3.10.0-327.el7.x86_64 x86_64 pangu_cache");
	curl_easy_setopt(ctx->curl, CURLOPT_NOSIGNAL,1L);
	curl_easy_setopt(ctx->curl, CURLOPT_WRITEFUNCTION, curl_get_response_body_cb);
	curl_easy_setopt(ctx->curl, CURLOPT_WRITEDATA, ctx);
	curl_easy_setopt(ctx->curl, CURLOPT_ERRORBUFFER, ctx->error);
	curl_easy_setopt(ctx->curl, CURLOPT_PRIVATE, ctx);
	curl_easy_setopt(ctx->curl, CURLOPT_FOLLOWLOCATION, 1L);
	curl_easy_setopt(ctx->curl, CURLOPT_CONNECTTIMEOUT_MS, 500L); 	
	curl_easy_setopt(ctx->curl, CURLOPT_HEADERFUNCTION, curl_get_response_header_cb);
	curl_easy_setopt(ctx->curl, CURLOPT_HEADERDATA, ctx);
	//ctx->error="Operation too slow. Less than 1024 bytes/sec transferred the last 3 seconds"
	curl_easy_setopt(ctx->curl, CURLOPT_LOW_SPEED_TIME, 2L);
	curl_easy_setopt(ctx->curl, CURLOPT_LOW_SPEED_LIMIT, 100L);

	rc = curl_multi_add_handle(ctx->instance->multi_hd, ctx->curl);
	assert(rc==CURLM_OK);
	return 0;
}