#include "builtin.h"
#include "cache.h"
#include "xdiff/xdiff.h"
#include "xdiff-interface.h"
 
static const char merge_file_usage[] =
"git merge-file [-p | --stdout] [-q | --quiet] [-L name1 [-L orig [-L name2]]] file1 orig_file file2";
 
int cmd_merge_file(int argc, const char **argv, const char *prefix)
{
  const char *names[3];
  mmfile_t mmfs[3];
  mmbuffer_t result = {NULL, 0};
  xpparam_t xpp = {XDF_NEED_MINIMAL};
  int ret = 0, i = 0, to_stdout = 0;
 
  while (argc > 4) {
    if (!strcmp(argv[1], "-L") && i < 3) {
      names[i++] = argv[2];
      argc--;
      argv++;
    } else if (!strcmp(argv[1], "-p") ||
        !strcmp(argv[1], "--stdout"))
      to_stdout = 1;
    else if (!strcmp(argv[1], "-q") ||
        !strcmp(argv[1], "--quiet"))
      freopen("/dev/null", "w", stderr);
    else
      usage(merge_file_usage);
    argc--;
    argv++;
  }
 
  if (argc != 4)
    usage(merge_file_usage);
 
  for (; i < 3; i++)
    names[i] = argv[i + 1];
 
  for (i = 0; i < 3; i++) {
    if (read_mmfile(mmfs + i, argv[i + 1]))
      return -1;
    if (buffer_is_binary(mmfs[i].ptr, mmfs[i].size))
      return error("Cannot merge binary files: %s\n",
          argv[i + 1]);
  }
 
  ret = xdl_merge(mmfs + 1, mmfs + 0, names[0], mmfs + 2, names[2],
      &xpp, XDL_MERGE_ZEALOUS, &result);
 
  for (i = 0; i < 3; i++)
    free(mmfs[i].ptr);
 
  if (ret >= 0) {
    const char *filename = argv[1];
    FILE *f = to_stdout ? stdout : fopen(filename, "wb");
 
    if (!f)
      ret = error("Could not open %s for writing", filename);
    else if (fwrite(result.ptr, result.size, 1, f) != 1)
      ret = error("Could not write to %s", filename);
    else if (fclose(f))
      ret = error("Could not close %s", filename);
    free(result.ptr);
  }
 
  return ret;
}