/*
 * stat_client.h - Library for access to VPP statistics segment
 *
 * Copyright (c) 2018 Cisco and/or its affiliates.
 * 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.
 */
#ifndef included_stat_client_h
#define included_stat_client_h

#define STAT_VERSION_MAJOR     1
#define STAT_VERSION_MINOR     2

#include <stdint.h>
#include <unistd.h>
#include <vlib/counter_types.h>
#include <time.h>
#include <stdbool.h>
#include <vlib/stats/shared.h>

/* Default socket to exchange segment fd */
/* TODO: Get from runtime directory */
#define STAT_SEGMENT_SOCKET_FILE "/run/vpp/stats.sock"
#define STAT_SEGMENT_SOCKET_FILENAME "stats.sock"

typedef struct
{
  char *name;
  stat_directory_type_t type;
  bool via_symlink;
  union
  {
    double scalar_value;
    counter_t *error_vector;
    counter_t **simple_counter_vec;
    vlib_counter_t **combined_counter_vec;
    uint8_t **name_vector;
  };
} stat_segment_data_t;

typedef struct
{
  uint64_t current_epoch;
  vlib_stats_shared_header_t *shared_header;
  vlib_stats_entry_t *directory_vector;
  ssize_t memory_size;
  uint64_t timeout;
} stat_client_main_t;

extern stat_client_main_t stat_client_main;

stat_client_main_t *stat_client_get (void);
void stat_client_free (stat_client_main_t * sm);
int stat_segment_connect_r (const char *socket_name, stat_client_main_t * sm);
int stat_segment_connect (const char *socket_name);
void stat_segment_disconnect_r (stat_client_main_t * sm);
void stat_segment_disconnect (void);
uint8_t **stat_segment_string_vector (uint8_t ** string_vector,
				      const char *string);
int stat_segment_vec_len (void *vec);
void stat_segment_vec_free (void *vec);
uint32_t *stat_segment_ls_r (uint8_t ** patterns, stat_client_main_t * sm);
uint32_t *stat_segment_ls (uint8_t ** pattern);
stat_segment_data_t *stat_segment_dump_r (uint32_t * stats,
					  stat_client_main_t * sm);
stat_segment_data_t *stat_segment_dump (uint32_t * counter_vec);
stat_segment_data_t *stat_segment_dump_entry_r (uint32_t index,
						stat_client_main_t * sm);
stat_segment_data_t *stat_segment_dump_entry (uint32_t index);

void stat_segment_data_free (stat_segment_data_t * res);
double stat_segment_heartbeat_r (stat_client_main_t * sm);
double stat_segment_heartbeat (void);

char *stat_segment_index_to_name_r (uint32_t index, stat_client_main_t * sm);
char *stat_segment_index_to_name (uint32_t index);
uint64_t stat_segment_version (void);
uint64_t stat_segment_version_r (stat_client_main_t * sm);

typedef struct
{
  uint64_t epoch;
} stat_segment_access_t;

static inline uint64_t
_time_now_nsec (void)
{
  struct timespec ts;
  clock_gettime (CLOCK_REALTIME, &ts);
  return 1e9 * ts.tv_sec + ts.tv_nsec;
}

static inline void *
stat_segment_adjust (stat_client_main_t * sm, void *data)
{
  char *csh = (char *) sm->shared_header;
  char *p = csh + ((char *) data - (char *) sm->shared_header->base);
  if (p > csh && p + sizeof (p) < csh + sm->memory_size)
    return (void *) p;
  return 0;
}

/*
 * Returns 0 on success, -1 on failure (timeout)
 */
static inline int
stat_segment_access_start (stat_segment_access_t * sa,
			   stat_client_main_t * sm)
{
  vlib_stats_shared_header_t *shared_header = sm->shared_header;
  uint64_t max_time;

  sa->epoch = shared_header->epoch;
  if (sm->timeout)
    {
      max_time = _time_now_nsec () + sm->timeout;
      while (shared_header->in_progress != 0 && _time_now_nsec () < max_time)
	;
    }
  else
    {
      while (shared_header->in_progress != 0)
	;
    }
  sm->directory_vector = (vlib_stats_entry_t *) stat_segment_adjust (
    sm, (void *) sm->shared_header->directory_vector);
  if (sm->timeout)
    return _time_now_nsec () < max_time ? 0 : -1;
  return 0;
}

/*
 * set maximum number of nano seconds to wait for in_progress state
 */
static inline void
stat_segment_set_timeout_nsec (stat_client_main_t * sm, uint64_t timeout)
{
  sm->timeout = timeout;
}

/*
 * set maximum number of nano seconds to wait for in_progress state
 * this function can be called directly by module using shared stat
 * segment
 */
static inline void
stat_segment_set_timeout (uint64_t timeout)
{
  stat_client_main_t *sm = &stat_client_main;
  stat_segment_set_timeout_nsec (sm, timeout);
}


static inline bool
stat_segment_access_end (stat_segment_access_t * sa, stat_client_main_t * sm)
{
  vlib_stats_shared_header_t *shared_header = sm->shared_header;

  if (shared_header->epoch != sa->epoch || shared_header->in_progress)
    return false;
  return true;
}

#endif /* included_stat_client_h */

/*
 * fd.io coding-style-patch-verification: ON
 *
 * Local Variables:
 * eval: (c-set-style "gnu")
 * End:
 */