#define _FILE_OFFSET_BITS 64
#include <sys/types.h>
#include <unistd.h>
#include <sys/mman.h>
#include "mstorage.h"

#ifdef UNITTEST
#include <errno.h>
int failafter=0;
void* my_mmap(void* addr, size_t len, int prot, int flags, int fd, off_t ofs) {
  if (--failafter == 0) {
    errno=EINVAL;
    return MAP_FAILED;
  }
  return mmap(addr,len,prot,flags,fd,ofs);
}
#define mmap my_mmap
#endif

int mstorage_init_persistent(mstorage_t* p,int fd) {
  off_t o;
  p->fd=fd;
  p->mapped=p->used=0;
  p->root=NULL;
  o=lseek(fd,0,SEEK_END);
  if (o==-1)
    return -1;
  if (o==0) {
    if (ftruncate(fd,4096)==-1)
      return -1;
    o=4096;
  }
  p->root=mmap(0,o,PROT_READ|PROT_WRITE,MAP_SHARED,fd,0);
  if (p->root==MAP_FAILED) {
    p->root=NULL;
    return -1;
  }
  p->mapped=p->used=o;
  return 0;
}

#ifdef UNITTEST
#include <assert.h>
#include <stdlib.h>
#include <fcntl.h>
#include <sys/resource.h>

int main() {
  mstorage_t m;
  char filename[]="/tmp/fooXXXXXX";
  int fd;
  assert((fd=mkstemp(filename)) != -1);
  assert(unlink(filename) == 0);
  // success case
  assert(mstorage_init_persistent(&m, fd) == 0);
  assert(munmap(m.root, m.mapped) == 0);
  assert(close(fd) == 0);
  // make lseek fail
  int pipes[2];
  assert(pipe(pipes) == 0);
  assert(mstorage_init_persistent(&m, pipes[0]) == -1);
  close(pipes[0]); close(pipes[1]);
  // make ftruncate fail
  assert((fd=open(filename, O_RDWR|O_CREAT|O_EXCL, 0600)) != -1);
  assert(close(fd) == 0);
  assert((fd=open(filename, O_RDONLY)) != -1);
  assert(unlink(filename) == 0);
  // fd is now a read-only handle to a 0 byte file
  assert(mstorage_init_persistent(&m, fd) == -1);
  assert(m.root == NULL && m.mapped == 0);
  assert(close(fd) == 0);
  // make mmap fail
  failafter=1;
  assert((fd=open(filename, O_RDWR|O_CREAT|O_EXCL, 0600)) != -1);
  assert(unlink(filename) == 0);
  assert(mstorage_init_persistent(&m, fd) == -1);
  assert(m.root == NULL && m.mapped == 0);
  assert(close(fd) == 0);
  return 0;
}
#endif