#include "pangu_web_cache.h"
#include <tango_cache_pending.h>
#include <tango_cache_client.h>

#include <tfe_proxy.h>
#include <tfe_http.h>
#include <tfe_utils.h>

#include <MESA/MESA_prof_load.h>
#include <MESA/field_stat2.h>

#include <event2/event.h>
#include <event2/buffer.h>

enum cache_stat_field
{
	STAT_CACHE_QUERY,
	STAT_CACHE_QUERY_NOT_APPLICABLE,
	STAT_CACHE_QUERY_VERIFY,
	STAT_CACHE_QUERY_HIT,
	STAT_CACHE_QUERY_BYTES,
	STAT_CACHE_OVERRIDE_QUERY,
	STAT_CACHE_OVERRIDE_HIT,	
	STAT_CACHE_OVERRIDE_BYTES,
	STAT_CACHE_QUERY_ERR,
	STAT_CACHE_QUERY_ABANDON,
	STAT_CACHE_QUERYING,
	STAT_CACHE_META_QUERYING,
	STAT_CACHE_UPLOAD_CNT,
	STAT_CACHE_UPLOAD_OVERRIDE,
	STAT_CACHE_UPLOAD_FORBIDEN,
	STAT_CACHE_UPLOAD_ABANDON,
	STAT_CACHE_UPLOAD_ERR,
	STAT_CACHE_UPLOAD_BYTES,
	STAT_CACHE_UPLOADING,
	STAT_CACHE_MEMORY,
	STAT_CACHE_ACTIVE_SESSION,

	STAT_CACHE_QUERY_HIT_OJB_SIZE,
	STAT_CACHE_UPLOAD_OBJ_SIZE,
	STAT_CACHE_OVERRIDE_HIT_OBJ_SIZE,
	STAT_CACHE_OVERRIDE_UPLOAD_OBJ_SIZE,
	__CACHE_STAT_MAX
};
struct cache_handle
{
	unsigned int thread_count;
	int cache_undefined_obj_enabled;
	int query_undefined_obj_enabled;
	size_t cache_undefined_obj_min_size;
	int minimum_cache_seconds;
	struct tango_cache_instance **clients;

	long long get_concurrency_max;
	long long put_concurrency_max;

	screen_stat_handle_t fs_handle;
	long long stat_val[__CACHE_STAT_MAX];
	int fs_id[__CACHE_STAT_MAX];
	struct event_base* gc_evbase;
	struct event* gcev;	

	void* logger;
};
struct cache_update_context
{
	struct cache_handle* ref_cache_handle;
	struct tango_cache_ctx * write_ctx;
};
static void cache_gc_cb(evutil_socket_t fd, short what, void * arg)
{
	struct cache_handle* cache=(struct cache_handle *)arg;
	struct cache_statistics client_stat_sum, client_stat;
	memset(&client_stat_sum, 0, sizeof(client_stat_sum));
	long long *val_sum = (long long *)&client_stat_sum;
	long long *val = NULL;
	int i=0, j=0;
	for(i=0; i<cache->thread_count;i++)
	{
		tango_cache_get_statistics(cache->clients[i], &client_stat);
		val=(long long*)&client_stat;
		for(j=0; j<sizeof(client_stat)/sizeof(long long); j++)
		{
			val_sum[j]+=val[j];
		}
	}
	for(i=0;i<__CACHE_STAT_MAX;i++)
	{
		if(ATOMIC_READ(&(cache->stat_val[i]))!=0)
		{
			switch(i)
			{
				case STAT_CACHE_UPLOAD_BYTES:
				case STAT_CACHE_QUERY_BYTES:
				case STAT_CACHE_OVERRIDE_BYTES:
					//translate bytes to mega bytes.
					FS_operate(cache->fs_handle, cache->fs_id[i], 0, FS_OP_SET, ATOMIC_READ(&(cache->stat_val[i]))/(1024*1024));
					break;
				default:					
					FS_operate(cache->fs_handle, cache->fs_id[i], 0, FS_OP_SET, ATOMIC_READ(&(cache->stat_val[i])));
					break;
			}
		}
	}

	FS_operate(cache->fs_handle, cache->fs_id[STAT_CACHE_QUERY], 0, FS_OP_SET, client_stat_sum.get_recv_num);
	FS_operate(cache->fs_handle, cache->fs_id[STAT_CACHE_QUERY_HIT], 0, FS_OP_SET, client_stat_sum.get_succ_num);
	FS_operate(cache->fs_handle, cache->fs_id[STAT_CACHE_QUERY_ERR], 0, FS_OP_SET, client_stat_sum.get_error_num);
	FS_operate(cache->fs_handle, cache->fs_id[STAT_CACHE_UPLOAD_CNT], 0, FS_OP_SET, client_stat_sum.put_recv_num);
	FS_operate(cache->fs_handle, cache->fs_id[STAT_CACHE_UPLOAD_ERR], 0, FS_OP_SET, client_stat_sum.put_error_num);	
	FS_operate(cache->fs_handle, cache->fs_id[STAT_CACHE_MEMORY], 0, FS_OP_SET, client_stat_sum.memory_used/(1024*1024));
	FS_operate(cache->fs_handle, cache->fs_id[STAT_CACHE_ACTIVE_SESSION], 0, FS_OP_SET, client_stat_sum.session_num);
	FS_operate(cache->fs_handle, cache->fs_id[STAT_CACHE_UPLOAD_ABANDON], 0, FS_OP_SET, client_stat_sum.totaldrop_num);
	FS_passive_output(cache->fs_handle);
	return;
}
struct cache_stat_sepc
{
	const char* name;
	enum field_dsp_style_t style;
	enum field_calc_algo calc_type;
};

static void set_stat_spec(struct cache_stat_sepc* spec, const char* name, enum field_dsp_style_t style, enum field_calc_algo calc_type)
{
	spec->name=name;
	spec->style=style;
	spec->calc_type=calc_type;
	return;
}
void cache_stat_init(struct cache_handle* cache)
{
	const char* fieldstat_output="./cache.fieldstat";
	const char* app_name="tango_cache";
	const char* obj_size_bins_KB="10,100,1000,10000";
	
	int value=0, i=0;
	screen_stat_handle_t fs_handle=NULL;
	fs_handle=FS_create_handle();
	FS_set_para(fs_handle, OUTPUT_DEVICE, fieldstat_output, strlen(fieldstat_output)+1);
	value=1;
	FS_set_para(fs_handle, PRINT_MODE, &value, sizeof(value));
	value=0;
	FS_set_para(fs_handle, CREATE_THREAD, &value, sizeof(value));
	FS_set_para(fs_handle, APP_NAME, app_name, strlen(app_name)+1);
	FS_set_para(fs_handle, HISTOGRAM_GLOBAL_BINS, obj_size_bins_KB, strlen(obj_size_bins_KB)+1);

	cache->fs_handle=fs_handle;

	struct cache_stat_sepc spec[__CACHE_STAT_MAX];
	
	set_stat_spec(&spec[STAT_CACHE_QUERY], "cache_get",FS_STYLE_FIELD, FS_CALC_CURRENT);
	set_stat_spec(&spec[STAT_CACHE_QUERY_NOT_APPLICABLE], "get_forbid",FS_STYLE_FIELD, FS_CALC_CURRENT);
	set_stat_spec(&spec[STAT_CACHE_QUERY_VERIFY], "get_verify",FS_STYLE_FIELD, FS_CALC_CURRENT);
	set_stat_spec(&spec[STAT_CACHE_QUERY_HIT], "hit_num",FS_STYLE_FIELD, FS_CALC_CURRENT);
	set_stat_spec(&spec[STAT_CACHE_QUERY_BYTES], "downloaded(MB)",FS_STYLE_FIELD, FS_CALC_CURRENT);
	set_stat_spec(&spec[STAT_CACHE_OVERRIDE_QUERY], "or_qry",FS_STYLE_FIELD, FS_CALC_CURRENT);
	set_stat_spec(&spec[STAT_CACHE_OVERRIDE_HIT], "or_hit",FS_STYLE_FIELD, FS_CALC_CURRENT);
	set_stat_spec(&spec[STAT_CACHE_OVERRIDE_BYTES], "or_download(MB)",FS_STYLE_FIELD, FS_CALC_CURRENT);
	set_stat_spec(&spec[STAT_CACHE_QUERY_ERR], "get_err",FS_STYLE_STATUS, FS_CALC_CURRENT);
	set_stat_spec(&spec[STAT_CACHE_QUERY_ABANDON], "get_abandon",FS_STYLE_STATUS, FS_CALC_CURRENT);
	set_stat_spec(&spec[STAT_CACHE_QUERYING], "getting",FS_STYLE_STATUS, FS_CALC_CURRENT);
	set_stat_spec(&spec[STAT_CACHE_UPLOAD_CNT], "cache_put",FS_STYLE_FIELD, FS_CALC_CURRENT);
	set_stat_spec(&spec[STAT_CACHE_UPLOAD_OVERRIDE], "or_put",FS_STYLE_FIELD, FS_CALC_CURRENT);
	set_stat_spec(&spec[STAT_CACHE_UPLOAD_FORBIDEN], "put_forbid",FS_STYLE_FIELD, FS_CALC_CURRENT);
	set_stat_spec(&spec[STAT_CACHE_UPLOAD_ABANDON], "put_abandon",FS_STYLE_FIELD, FS_CALC_CURRENT);
	set_stat_spec(&spec[STAT_CACHE_UPLOAD_ERR], "put_err",FS_STYLE_STATUS, FS_CALC_CURRENT);
	set_stat_spec(&spec[STAT_CACHE_UPLOAD_BYTES], "put(MB)",FS_STYLE_FIELD, FS_CALC_CURRENT);
	set_stat_spec(&spec[STAT_CACHE_UPLOADING], "putting",FS_STYLE_STATUS, FS_CALC_CURRENT);
	set_stat_spec(&spec[STAT_CACHE_MEMORY], "used_mem(MB)",FS_STYLE_STATUS, FS_CALC_CURRENT);
	set_stat_spec(&spec[STAT_CACHE_ACTIVE_SESSION], "active_sess",FS_STYLE_STATUS, FS_CALC_CURRENT);

	set_stat_spec(&spec[STAT_CACHE_OVERRIDE_HIT_OBJ_SIZE], "or_hit_obj(KB)",FS_STYLE_HISTOGRAM, FS_CALC_CURRENT);
	set_stat_spec(&spec[STAT_CACHE_QUERY_HIT_OJB_SIZE], "hitted_obj(KB)",FS_STYLE_HISTOGRAM, FS_CALC_CURRENT);
	set_stat_spec(&spec[STAT_CACHE_UPLOAD_OBJ_SIZE], "cached_obj(KB)",FS_STYLE_HISTOGRAM, FS_CALC_CURRENT);
	set_stat_spec(&spec[STAT_CACHE_OVERRIDE_UPLOAD_OBJ_SIZE], "or_cached(KB)",FS_STYLE_HISTOGRAM, FS_CALC_CURRENT);

	
	for(i=0;i<__CACHE_STAT_MAX;i++)
	{
		cache->fs_id[i]=FS_register(cache->fs_handle, spec[i].style, spec[i].calc_type, spec[i].name);
	}
//	value=cache->fs_id[STAT_CACHE_QUERY_HIT];
//	FS_set_para(cache->fs_handle, ID_INVISBLE, &value, sizeof(value));

	FS_register_ratio(cache->fs_handle,
					cache->fs_id[STAT_CACHE_QUERY_HIT], 
					cache->fs_id[STAT_CACHE_QUERY], 	
					1,
					FS_STYLE_STATUS,
					FS_CALC_CURRENT,
					"cache_hit");

	value=cache->fs_id[STAT_CACHE_OVERRIDE_HIT];
	FS_set_para(cache->fs_handle, ID_INVISBLE, &value, sizeof(value));

	FS_register_ratio(cache->fs_handle,
					cache->fs_id[STAT_CACHE_OVERRIDE_HIT], 
					cache->fs_id[STAT_CACHE_OVERRIDE_QUERY], 
					1,
					FS_STYLE_STATUS,
					FS_CALC_CURRENT,
					"override_hit");

	
	FS_start(cache->fs_handle);
	
	struct timeval gc_delay = {0, 500*1000};	//Microseconds, we set 500 miliseconds here.
	cache->gcev = event_new(cache->gc_evbase, -1, EV_PERSIST, cache_gc_cb, cache);	
    evtimer_add(cache->gcev, &gc_delay);	
	return;
}
struct cache_handle* create_web_cache_handle(const char* profile_path, const char* section, struct event_base* gc_evbase, void *logger)
{
	struct cache_handle* cache=ALLOC(struct cache_handle, 1);
	int temp=0;	
	cache->logger=logger;
	cache->thread_count=tfe_proxy_get_work_thread_count();
	cache->clients=ALLOC(struct tango_cache_instance *, cache->thread_count);
	int i=0;
	for(i=0; i<cache->thread_count; i++)
	{
		cache->clients[i]=tango_cache_instance_new(tfe_proxy_get_work_thread_evbase(i), profile_path, section, logger);
		if(cache->clients[i]==NULL)
		{
			goto error_out;
		}
	}
	
	MESA_load_profile_int_def(profile_path, section, "get_concurrency_max", &temp, 1000*1000);
	cache->put_concurrency_max=temp;
	MESA_load_profile_int_def(profile_path, section, "put_concurrency_max", &(temp), 1000*1000);
	cache->put_concurrency_max=temp;
	MESA_load_profile_int_def(profile_path, section, "query_undefined_obj", &(cache->query_undefined_obj_enabled), 1);
	MESA_load_profile_int_def(profile_path, section, "cache_undefined_obj", &(cache->cache_undefined_obj_enabled), 1);
	MESA_load_profile_int_def(profile_path, section, "cached_undefined_obj_minimum_size", &(temp), 100*1024);
	cache->cache_undefined_obj_min_size=temp;
	MESA_load_profile_int_def(profile_path, section, "cache_minimum_time_override", &(cache->minimum_cache_seconds), 60*5);

	cache->gc_evbase=gc_evbase;	
	cache_stat_init(cache);
	return cache;
error_out:
	free(cache);
	return NULL;
}

static char* read_http1_hdr(const char* hdr, const char* field_name)
{	
	const char *p=NULL, *q=NULL;
	char* value=NULL;
	p=strcasestr(hdr, field_name);
	if(p==NULL)
	{
		return NULL;
	}
	p=strstr(p, ":");
	if(p==NULL)
	{
		return NULL;
	}
	p++;
	q=strcasestr(p, "\r\n");
	if(q==NULL)
	{
		return NULL;
	}
	value=(char*) calloc(sizeof(char), (q-p+1));
	memcpy(value, p, q-p);
	return value;
}

enum cache_query_result_type cache_query_result_get_type(future_result_t * result)
{
	struct tango_cache_result* cache_result=tango_cache_read_result(result);
	enum cache_query_result_type map[__CACHE_QUERY_RESULT_MAX];
	map[RESULT_TYPE_BODY]=CACHE_QUERY_RESULT_DATA;
	map[RESULT_TYPE_HEADER]=CACHE_QUERY_RESULT_META;
	map[RESULT_TYPE_USERTAG]=CACHE_QUERY_RESULT_IRRELEVANT;
	map[RESULT_TYPE_END]=CACHE_QUERY_RESULT_END;
	map[RESULT_TYPE_MISS]=CACHE_QUERY_RESULT_MISS;
	return map[cache_result->type];
}


struct cached_meta* cache_query_result_get_header(future_result_t * result)
{
	struct tango_cache_result* cache_result=tango_cache_read_result(result);
	struct cached_meta* meta;
	if(cache_result->type!=RESULT_TYPE_HEADER)
	{
		return NULL;
	}
	meta= ALLOC(struct cached_meta, 1);
	meta->content_length=cache_result->tlength;
	meta->content_type=read_http1_hdr((const char*)cache_result->data_frag, "content-type");
	return meta;
}
size_t cache_query_result_get_data(future_result_t * result, const unsigned char** pp_data)
{
	struct tango_cache_result* cache_result=tango_cache_read_result(result);
	assert(cache_result->type==RESULT_TYPE_BODY);
	*pp_data=(const unsigned char*)cache_result->data_frag;
	return cache_result->size;
}
struct cache_query_context
{
	struct cache_handle* ref_handle;
	char* url;

	struct cached_meta meta;
	
	struct tango_cache_result* ref_tango_cache_result;
	struct future* f_tango_cache_fetch;
};
void cache_query_ctx_free_cb(void* p)
{
	struct cache_query_context* ctx=(struct cache_query_context*)p;
	future_destroy(ctx->f_tango_cache_fetch);
	ctx->f_tango_cache_fetch=NULL;
	FREE(&(ctx->url));
	FREE(&(ctx->meta.etag));
	FREE(&(ctx->meta.last_modified));
	FREE(&(ctx->meta.content_type));
	free(ctx);
}
const struct cached_meta* cache_query_result_read_meta(future_result_t * result)
{
	struct cache_query_context* ctx=(struct cache_query_context*)result;
	return &(ctx->meta);
}
void cached_meta_set(struct cached_meta* meta, enum CACHE_RESULT_TYPE type, const char* data_frag, size_t size)
{
	switch(type)
	{
		case RESULT_TYPE_HEADER:
			meta->content_type=read_http1_hdr((const char*)data_frag, "content-type");
			break;
		case RESULT_TYPE_USERTAG:
			meta->last_modified=read_http1_hdr(data_frag, "Last-Modified");
			meta->etag=read_http1_hdr(data_frag, "etag");
			break;
		default:
			assert(0);
			break;
	}
	return;
}

static void cache_query_obj_on_succ(future_result_t * result, void * user)
{
	struct promise * p = (struct promise *) user;
	struct cache_query_context* ctx=(struct cache_query_context*)promise_get_ctx(p);
	struct tango_cache_result* _result=tango_cache_read_result(result);
	
	switch(_result->type)
	{
		case RESULT_TYPE_HEADER:
			ATOMIC_INC(&(ctx->ref_handle->stat_val[STAT_CACHE_QUERY_HIT]));
			FS_operate(ctx->ref_handle->fs_handle, ctx->ref_handle->fs_id[STAT_CACHE_QUERY_HIT_OJB_SIZE], 0, FS_OP_SET, _result->tlength/1024);
			cached_meta_set(&ctx->meta, RESULT_TYPE_HEADER, _result->data_frag, _result->size);
			ctx->meta.content_length=_result->tlength;
			TFE_LOG_DEBUG(ctx->ref_handle->logger, "cache query hit: %s", ctx->url);
			break;
		case RESULT_TYPE_USERTAG:		
			cached_meta_set(&ctx->meta, RESULT_TYPE_USERTAG, _result->data_frag, _result->size);
			break;
		case RESULT_TYPE_MISS:
			TFE_LOG_DEBUG(ctx->ref_handle->logger, "cache query miss: %s", ctx->url);
			//NOT break intentionally.
		case RESULT_TYPE_END:
			//last call.	
			ATOMIC_DEC(&(ctx->ref_handle->stat_val[STAT_CACHE_QUERYING]));	
			promise_dettach_ctx(p);
			cache_query_ctx_free_cb(ctx);
			break;
		case RESULT_TYPE_BODY:
			ATOMIC_ADD(&(ctx->ref_handle->stat_val[STAT_CACHE_QUERY_BYTES]), _result->size);
			break;
		default:
			break;
	}
	promise_success(p, result);

	return;
}
static void cache_query_obj_on_fail(enum e_future_error err, const char * what, void * user)
{
	struct promise * p = (struct promise *) user;
	struct cache_query_context* ctx=(struct cache_query_context*)promise_dettach_ctx(p);
	promise_failed(p, err, what);	
	ATOMIC_DEC(&(ctx->ref_handle->stat_val[STAT_CACHE_QUERYING]));	
	cache_query_ctx_free_cb(ctx);
	return;
}


struct cache_pending_context
{
	enum cache_pending_result status;
	int is_undefined_obj;
	struct request_freshness req_fresshness;
	char* req_if_none_match, *req_if_modified_since;
	const struct tfe_http_half * request;

	char* url;
	struct cached_meta cached_obj_meta;
	
	struct cache_handle* ref_handle;
	struct tango_cache_result* ref_tango_cache_result;
	struct future* f_tango_cache_fetch;
};
void cache_pending_ctx_free_cb(void* p)
{
	struct cache_pending_context* ctx=(struct cache_pending_context*)p;
	ctx->request=NULL;
	free(ctx->url);
	free(ctx);
	return;
}
const struct cached_meta* cache_pending_result_read_meta(future_result_t * result)
{
	struct cache_pending_context* ctx=(struct cache_pending_context*)result;
	return &(ctx->cached_obj_meta);
}

static void cache_query_meta_on_succ(future_result_t * result, void * user)
{
	struct promise * p = (struct promise *) user;
	struct cache_pending_context* ctx=(struct cache_pending_context*)promise_get_ctx(p);
	struct tango_cache_result* _result=tango_cache_read_result(result);
	ctx->ref_tango_cache_result=_result;
	time_t cache_last_modified_time=0, request_last_modified_time=0;
	switch(_result->type)
	{
		case RESULT_TYPE_HEADER:
			ctx->cached_obj_meta.content_length=_result->tlength;
			cached_meta_set(&ctx->cached_obj_meta, RESULT_TYPE_HEADER, _result->data_frag, _result->size);
			ctx->status=PENDING_RESULT_REVALIDATE;
			break;
		case RESULT_TYPE_USERTAG:
			cached_meta_set(&ctx->cached_obj_meta, RESULT_TYPE_HEADER, _result->data_frag, _result->size);
			TFE_LOG_DEBUG(ctx->ref_handle->logger, "cache meta query hit: %s %s %s"
							, ctx->url
							, ctx->cached_obj_meta.last_modified ? ctx->cached_obj_meta.last_modified:"no_last_modify"
							, ctx->cached_obj_meta.etag ? ctx->cached_obj_meta.etag:"no_etag");
			break;
		case RESULT_TYPE_MISS:
			ctx->status=PENDING_RESULT_MISS;
			TFE_LOG_DEBUG(ctx->ref_handle->logger, "cache meta query miss: %s", ctx->url);
			//NOT break intentionally.
		case RESULT_TYPE_END:
			//last call.	
			ATOMIC_DEC(&(ctx->ref_handle->stat_val[STAT_CACHE_META_QUERYING]));	
			promise_dettach_ctx(p);		
			promise_success(p, ctx);
			cache_query_ctx_free_cb(ctx);
			break;
		default:
			break;
	}

}
static void cache_query_meta_on_fail(enum e_future_error err, const char * what, void * user)
{
	struct promise * p = (struct promise *) user;
	struct cache_pending_context* ctx=(struct cache_pending_context*)promise_dettach_ctx(p);
	promise_failed(p, err, what);	
	ATOMIC_DEC(&(ctx->ref_handle->stat_val[STAT_CACHE_META_QUERYING]));	
	cache_query_ctx_free_cb(ctx);
	return;
}

enum cache_pending_result web_cache_async_pending(struct cache_handle* handle, unsigned int thread_id,
												const struct tfe_http_half * request, struct future* f_revalidate)
{	
	struct request_freshness req_fresshness={0,0};
	enum cache_pending_result result=PENDING_RESULT_FOBIDDEN;
	int is_undefined_obj=0;
	enum cache_pending_action get_action=tfe_cache_get_pending(request, &(req_fresshness));
	switch(get_action)
	{
		case UNDEFINED:
			if(!handle->query_undefined_obj_enabled)
			{
				ATOMIC_INC(&(handle->stat_val[STAT_CACHE_QUERY_NOT_APPLICABLE]));
				result=PENDING_RESULT_FOBIDDEN;
			}
			else
			{
				is_undefined_obj=1;
				ATOMIC_INC(&(handle->stat_val[STAT_CACHE_OVERRIDE_QUERY]));
				result=PENDING_RESULT_ALLOWED;
			}
			break;
		case FORBIDDEN:
			ATOMIC_INC(&(handle->stat_val[STAT_CACHE_QUERY_NOT_APPLICABLE]));
			result=PENDING_RESULT_FOBIDDEN;
			break;
		case ALLOWED:
			result=PENDING_RESULT_ALLOWED;
			break;
		default:
			result=PENDING_RESULT_REVALIDATE;
			break;
	}
	if(result!=PENDING_RESULT_REVALIDATE)
	{
		return result;
	}
	
	struct tango_cache_meta_get meta;
	memset(&meta, 0, sizeof(meta));
	meta.url=request->req_spec.url;
	meta.get=req_fresshness;
	
	struct promise* p=future_to_promise(f_revalidate);
	struct cache_pending_context* ctx=ALLOC(struct cache_pending_context, 1);
	ctx->status=PENDING_RESULT_FOBIDDEN;	
	ctx->ref_handle=handle;
	ctx->req_fresshness=req_fresshness;
	ctx->url=tfe_strdup(request->req_spec.url);
	ctx->req_if_modified_since=tfe_strdup(tfe_http_std_field_read(request, TFE_HTTP_IF_MODIFIED_SINCE));
	ctx->req_if_none_match=tfe_strdup(tfe_http_std_field_read(request, TFE_HTTP_IF_NONE_MATCH));
	promise_set_ctx(p, ctx, cache_pending_ctx_free_cb);

	ATOMIC_INC(&(handle->stat_val[STAT_CACHE_META_QUERYING]));		
	ctx->f_tango_cache_fetch=future_create("_cache_meta", cache_query_meta_on_succ, cache_query_meta_on_fail, p);
	int ret=tango_cache_head_object(handle->clients[thread_id], ctx->f_tango_cache_fetch, &meta);
	assert(ret==0);
	return PENDING_RESULT_REVALIDATE;
}
int web_cache_async_query(struct cache_handle* handle, unsigned int thread_id,
									const struct tfe_http_half * request, struct future* f)
{
	struct request_freshness req_fresshness;
	enum cache_pending_action get_action;	
	struct cache_query_context* query_ctx=NULL;
	struct promise* p=NULL;
	struct future* _f=NULL;

	get_action=tfe_cache_get_pending(request, &req_fresshness);
	assert(get_action!=FORBIDDEN);
	
	if(ATOMIC_READ(&(handle->stat_val[STAT_CACHE_QUERYING])) > ATOMIC_READ(&(handle->put_concurrency_max)))
	{		
		ATOMIC_INC(&(handle->stat_val[STAT_CACHE_QUERY_ABANDON]));	
		return -1;
	}

	struct tango_cache_meta_get meta;
	memset(&meta, 0, sizeof(meta));
	meta.url=request->req_spec.url;
	memcpy(&(meta.get), &req_fresshness, sizeof(meta.get));
	query_ctx=ALLOC(struct cache_query_context, 1);
	query_ctx->ref_handle=handle;
	query_ctx->url=tfe_strdup(request->req_spec.url);

	p=future_to_promise(f);
	promise_set_ctx(p, query_ctx, cache_query_ctx_free_cb);
	
	ATOMIC_INC(&(handle->stat_val[STAT_CACHE_QUERYING]));	
	query_ctx->f_tango_cache_fetch=future_create("_cache_get", cache_query_obj_on_succ, cache_query_obj_on_fail, p);
	int ret=tango_cache_fetch_object(handle->clients[thread_id], query_ctx->f_tango_cache_fetch, &meta);	
	return 0;
}
struct wrap_cache_put_ctx
{
	char* url;
	time_t start;
	struct future* f;
	struct cache_handle* ref_handle;
};
void wrap_cache_put_ctx_free(struct wrap_cache_put_ctx* ctx)
{
	FREE(&(ctx->url));
	future_destroy(ctx->f);
	free(ctx);
}
static void wrap_cache_update_on_succ(future_result_t * result, void * user)
{
	struct wrap_cache_put_ctx* ctx=(struct wrap_cache_put_ctx*)user;
	TFE_LOG_DEBUG(ctx->ref_handle->logger, "cache upload success: %s elapse: %d", ctx->url, time(NULL)-ctx->start);
	wrap_cache_put_ctx_free(ctx);
}
static void wrap_cache_update_on_fail(enum e_future_error err, const char * what, void * user)
{
	struct wrap_cache_put_ctx* ctx=(struct wrap_cache_put_ctx*)user;
	TFE_LOG_DEBUG(ctx->ref_handle->logger, "cache upload failed: %s elapse: %d", ctx->url, time(NULL)-ctx->start);
	wrap_cache_put_ctx_free(ctx);
}

struct cache_update_context* web_cache_update_start(struct cache_handle* handle, unsigned int thread_id, 
															const struct tfe_http_session * session)
{
	struct cache_update_context* update_ctx=NULL;
	struct response_freshness resp_freshness;
	enum cache_pending_action put_action;
	struct tango_cache_ctx *write_ctx=NULL;
	char cont_len_str[TFE_STRING_MAX]={0}, user_tag_str[TFE_STRING_MAX]={0};
	const char* value=NULL;
	char *tmp=NULL;
	int i=0, is_undefined_obj=0;
	size_t content_len=0;
	if(session->resp->resp_spec.content_length)
	{
		sscanf(session->resp->resp_spec.content_length, "%lu", &content_len);
	}
	
	put_action=tfe_cache_put_pending(session->resp, &resp_freshness);
	switch(put_action){
		case FORBIDDEN:
		case REVALIDATE:
			ATOMIC_INC(&(handle->stat_val[STAT_CACHE_UPLOAD_FORBIDEN]));
			TFE_LOG_DEBUG(handle->logger, "cache update forbiden: %s", session->req->req_spec.url);
			return NULL;
		case ALLOWED:
			break;
		case UNDEFINED:
			if(handle->cache_undefined_obj_enabled && content_len<handle->cache_undefined_obj_min_size)
			{
				TFE_LOG_DEBUG(handle->logger, "cache update forbiden: %s", session->req->req_spec.url);
				return NULL;
			}
			is_undefined_obj=1;
			break;
		default:
			assert(0);
			break;
	}
	if(ATOMIC_READ(&(handle->stat_val[STAT_CACHE_UPLOADING])) > handle->get_concurrency_max)
	{		
		ATOMIC_INC(&(handle->stat_val[STAT_CACHE_UPLOAD_ABANDON]));	
		return NULL;
	}
	ATOMIC_INC(&(handle->stat_val[STAT_CACHE_UPLOADING]));
	
	struct tango_cache_meta_put meta;
	memset(&meta, 0, sizeof(meta));
	meta.url=session->req->req_spec.url;
	i=0;	

	snprintf(cont_len_str, sizeof(cont_len_str), "content-type:%s",session->resp->resp_spec.content_type);
	meta.std_hdr[i]=cont_len_str;
	i++;
	const char* etag=tfe_http_std_field_read(session->resp, TFE_HTTP_ETAG);
	const char* last_modified=tfe_http_std_field_read(session->resp, TFE_HTTP_LAST_MODIFIED);
	tmp=user_tag_str;
	if(etag) tmp+=snprintf(tmp, sizeof(user_tag_str)-(tmp-user_tag_str), "etag:%s\r\n", etag);
	if(last_modified) tmp+=snprintf(tmp, sizeof(user_tag_str)-(tmp-user_tag_str), "Last-modified:%s\r\n", last_modified);
	if(strlen(user_tag_str)>0)
	{
		meta.usertag=user_tag_str;
		meta.usertag_len=strlen(user_tag_str)+1;
	}
	memcpy(&meta.put, &resp_freshness, sizeof(resp_freshness));
	
	struct wrap_cache_put_ctx* _cache_put_ctx=ALLOC(struct wrap_cache_put_ctx, 1);
	_cache_put_ctx->url=tfe_strdup(session->req->req_spec.url);
	_cache_put_ctx->start=time(NULL);
	_cache_put_ctx->ref_handle=handle;
	_cache_put_ctx->f=future_create("cache_put", wrap_cache_update_on_succ, wrap_cache_update_on_fail, _cache_put_ctx);
	TFE_LOG_DEBUG(handle->logger, "cache update allowed: %s", _cache_put_ctx->url);
	write_ctx=tango_cache_update_start(handle->clients[thread_id], _cache_put_ctx->f, &meta);
	if(write_ctx==NULL)//exceed maximum cache memory size.
	{
		wrap_cache_put_ctx_free(_cache_put_ctx);
		return NULL;
	}
	if(is_undefined_obj)
	{
		ATOMIC_INC(&(handle->stat_val[STAT_CACHE_UPLOAD_OVERRIDE]));
		FS_operate(handle->fs_handle,handle->fs_id[STAT_CACHE_OVERRIDE_UPLOAD_OBJ_SIZE], 0, FS_OP_SET, content_len/1024);
	}
	FS_operate(handle->fs_handle,handle->fs_id[STAT_CACHE_UPLOAD_OBJ_SIZE], 0, FS_OP_SET, content_len/1024);
	update_ctx=ALLOC(struct cache_update_context, 1);
	update_ctx->write_ctx=write_ctx;
	update_ctx->ref_cache_handle=handle;
	return update_ctx;

}
void web_cache_update(struct cache_update_context* ctx, const unsigned char * body_frag, size_t frag_size)
{
	tango_cache_update_frag_data(ctx->write_ctx, (const char*)body_frag, frag_size);
	ATOMIC_ADD(&(ctx->ref_cache_handle->stat_val[STAT_CACHE_UPLOAD_BYTES]), frag_size);
	return;
}
void web_cache_update_end(struct cache_update_context* ctx)
{
	tango_cache_update_end(ctx->write_ctx);
	free(ctx);
	ATOMIC_DEC(&(ctx->ref_cache_handle->stat_val[STAT_CACHE_UPLOADING]));		
	return;
}