/*

Copyright 2020 Google LLC

Use of this source code is governed by a BSD-style

license that can be found in the LICENSE file or at

https://developers.google.com/open-source/licenses/bsd

*/

#include "system.h"

#include "block.h"

#include "iter.h"

#include "record.h"

#include "reftable.h"

#include "tree.h"

struct file_block_source {

  int fd;

  uint64_t size;

};

static uint64_t file_size(void *b)

{

  return ((struct file_block_source *)b)->size;

}

static void file_return_block(void *b, struct reftable_block *dest)

{

  memset(dest->data, 0xff, dest->len);

  reftable_free(dest->data);

}

static void file_close(void *b)

{

  int fd = ((struct file_block_source *)b)->fd;

  if (fd > 0) {

    close(fd);

    ((struct file_block_source *)b)->fd = 0;

  }

  reftable_free(b);

}

static int file_read_block(void *v, struct reftable_block *dest, uint64_t off,

         uint32_t size)

{

  struct file_block_source *b = (struct file_block_source *)v;

  assert(off + size <= b->size);

  dest->data = reftable_malloc(size);

  if (pread(b->fd, dest->data, size, off) != size) {

    return -1;

  }

  dest->len = size;

  return size;

}

struct reftable_block_source_vtable file_vtable = {

  .size = &file_size,

  .read_block = &file_read_block,

  .return_block = &file_return_block,

  .close = &file_close,

};

int reftable_block_source_from_file(struct reftable_block_source *bs,

            const char *name)

{

  struct stat st = { 0 };

  int err = 0;

  int fd = open(name, O_RDONLY);

  if (fd < 0) {

    if (errno == ENOENT) {

      return REFTABLE_NOT_EXIST_ERROR;

    }

    return -1;

  }

  err = fstat(fd, &st);

  if (err < 0) {

    return -1;

  }

  {

    struct file_block_source *p =

      reftable_calloc(sizeof(struct file_block_source));

    p->size = st.st_size;

    p->fd = fd;

    assert(bs->ops == NULL);

    bs->ops = &file_vtable;

    bs->arg = p;

  }

  return 0;

}

int reftable_fd_write(void *arg, byte *data, size_t sz)

{

  int *fdp = (int *)arg;

  return write(*fdp, data, sz);

}