openstreetmap-mod_tile-python-implementation/store_null.c

#include "store_null.h"
#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <limits.h>

static int tile_read(struct storage_backend * store, 
		     const char *xmlconfig, 
		     int x, int y, int z, 
		     char *buf, size_t sz, 
		     int * compressed, char * err_msg) {
   snprintf(err_msg, PATH_MAX - 1, "Cannot read from NULL storage.");
   return -1;
}

static struct stat_info tile_stat(struct storage_backend * store, 
				  const char *xmlconfig, 
				  int x, int y, int z) {
   struct stat_info tile_stat;
   tile_stat.size = -1;
   tile_stat.atime = 0;
   tile_stat.mtime = 0;
   tile_stat.ctime = 0;
   tile_stat.expired = 1;
   return tile_stat;
}

static int metatile_write(struct storage_backend * store, 
			  const char *xmlconfig, 
			  int x, int y, int z, 
			  const char *buf, int sz) {
   // fake like we actually wrote the tile, but we didn't...
   return sz;
}

static int metatile_delete(struct storage_backend * store, 
			   const char *xmlconfig, 
			   int x, int y, int z) {
   return 0;
}

static int metatile_expire(struct storage_backend * store, 
			   const char *xmlconfig, 
			   int x, int y, int z) {
   return 0;
}

static char * tile_storage_id(struct storage_backend * store, 
			      const char *xmlconfig, 
			      int x, int y, int z, 
			      char * string) {
   snprintf(string, PATH_MAX - 1, "null://");
   return string;
}

static int close_storage(struct storage_backend * store) {
   return 0;
}

struct storage_backend *init_storage_null() {
   struct storage_backend *store = malloc(sizeof *store);
   if (store == NULL) {
      log_message(STORE_LOGLVL_ERR, "init_storage_null: Failed to allocate memory for storage backend");
      return NULL;
   }

   store->storage_ctx = NULL;
   store->tile_read = &tile_read;
   store->tile_stat = &tile_stat;
   store->metatile_write = &metatile_write;
   store->metatile_delete = &metatile_delete;
   store->metatile_expire = &metatile_expire;
   store->tile_storage_id = &tile_storage_id;
   store->close_storage = &close_storage;

   return store;
}