thodg/got/lib/diff.c

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• Hash : 7d283eee
  Author :
  Date : 2017-11-29T17:11:11
  

  add and test basic blob diffing functionality
  

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• lib/diff.c

• /*
   * Copyright (c) 2017 Stefan Sperling <stsp@openbsd.org>
   *
   * Permission to use, copy, modify, and distribute this software for any
   * purpose with or without fee is hereby granted, provided that the above
   * copyright notice and this permission notice appear in all copies.
   *
   * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
   * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
   * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
   * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
   * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
   * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
   * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
   */
  
  #include <sys/queue.h>
  
  #include <stdio.h>
  #include <stdlib.h>
  #include <string.h>
  #include <sha1.h>
  #include <zlib.h>
  
  #include "got_repository.h"
  #include "got_object.h"
  #include "got_error.h"
  
  #include "diff.h"
  
  static const struct got_error *
  open_tempfile(FILE **sfp, char **sfn)
  {
  	static const int sfnlen = 20;
  	int fd;
  
  	*sfn = calloc(sizeof(char), sfnlen);
  	if (*sfn == NULL)
  		return got_error(GOT_ERR_NO_MEM);
  	strlcpy(*sfn, "/tmp/got.XXXXXXXXXX", sfnlen);
  	if ((fd = mkstemp(*sfn)) == -1 ||
  	    ((*sfp) = fdopen(fd, "w+")) == NULL) {
  		if (fd != -1) {
  			unlink(*sfn);
  			close(fd);
  		}
  		free(*sfn);
  		return got_error(GOT_ERR_FILE_OPEN);
  	}
  	return NULL;
  }
  
  const struct got_error *
  got_diff_blob(struct got_blob_object *blob1, struct got_blob_object *blob2,
      FILE *outfile)
  {
  	const struct got_error *err = NULL;
  	FILE *f1, *f2;
  	char *n1, *n2;
  	size_t len, hdrlen;
  	int res;
  
  	err = open_tempfile(&f1, &n1);
  	if (err != NULL)
  		return err;
  
  	err = open_tempfile(&f2, &n2);
  	if (err != NULL) {
  		fclose(f1);
  		free(n1);
  		return err;
  	}
  
  
  	hdrlen = blob1->hdrlen;
  	do {
  		err = got_object_blob_read_block(blob1, &len);
  		if (err)
  			goto done;
  		/* Skip blob object header first time around. */
  		fwrite(blob1->zb.outbuf + hdrlen, len - hdrlen, 1, f1);
  		hdrlen = 0;
  	} while (len != 0);
  
  	hdrlen = blob2->hdrlen;
  	do {
  		err = got_object_blob_read_block(blob2, &len);
  		if (err)
  			goto done;
  		/* Skip blob object header first time around. */
  		fwrite(blob2->zb.outbuf + hdrlen, len - hdrlen, 1, f2);
  		hdrlen = 0;
  	} while (len != 0);
  
  	fflush(f1);
  	fflush(f2);
  
  	err = got_diffreg(&res, n1, n2, 0);
  done:
  	unlink(n1);
  	unlink(n2);
  	fclose(f1);
  	fclose(f2);
  	free(n1);
  	free(n2);
  	return err;
  }
  

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