thodg/libgit2/examples/common.c

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• Hash : 66902d47
  Author :
  Date : 2013-10-29T18:30:49
  

  Extract common example helpers and reorg examples This reorganizes a few of the examples so that the main function comes first with the argument parsing extracted into a helper that can come at the end of the file (so the example focuses more on the use of libgit2 instead of command line support). This also creates a shared examples/common.[ch] so that useful helper funcs can be shared across examples instead of repeated.

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• examples/common.c

• /*
   * Copyright (C) the libgit2 contributors. All rights reserved.
   *
   * This file is part of libgit2, distributed under the GNU GPL v2 with
   * a Linking Exception. For full terms see the included COPYING file.
   */
  
  #include "common.h"
  
  void check_lg2(int error, const char *message, const char *extra)
  {
  	const git_error *lg2err;
  	const char *lg2msg = "", *lg2spacer = "";
  
  	if (!error)
  		return;
  
  	if ((lg2err = giterr_last()) != NULL && lg2err->message != NULL) {
  		lg2msg = lg2err->message;
  		lg2spacer = " - ";
  	}
  
  	if (extra)
  		fprintf(stderr, "%s '%s' [%d]%s%s\n",
  			message, extra, error, lg2spacer, lg2msg);
  	else
  		fprintf(stderr, "%s [%d]%s%s\n",
  			message, error, lg2spacer, lg2msg);
  
  	exit(1);
  }
  
  void fatal(const char *message, const char *extra)
  {
  	if (extra)
  		fprintf(stderr, "%s %s\n", message, extra);
  	else
  		fprintf(stderr, "%s\n", message);
  
  	exit(1);
  }
  
  size_t is_prefixed(const char *str, const char *pfx)
  {
  	size_t len = strlen(pfx);
  	return strncmp(str, pfx, len) ? 0 : len;
  }
  
  int match_str_arg(
  	const char **out, struct args_info *args, const char *opt)
  {
  	const char *found = args->argv[args->pos];
  	size_t len = is_prefixed(found, opt);
  
  	if (!len)
  		return 0;
  
  	if (!found[len]) {
  		if (args->pos + 1 == args->argc)
  			fatal("expected value following argument", opt);
  		args->pos += 1;
  		*out = args->argv[args->pos];
  		return 1;
  	}
  
  	if (found[len] == '=') {
  		*out = found + len + 1;
  		return 1;
  	}
  
  	return 0;
  }
  
  static const char *match_numeric_arg(struct args_info *args, const char *opt)
  {
  	const char *found = args->argv[args->pos];
  	size_t len = is_prefixed(found, opt);
  
  	if (!len)
  		return NULL;
  
  	if (!found[len]) {
  		if (args->pos + 1 == args->argc)
  			fatal("expected numeric value following argument", opt);
  		args->pos += 1;
  		found = args->argv[args->pos];
  	} else {
  		found = found + len;
  		if (*found == '=')
  			found++;
  	}
  
  	return found;
  }
  
  int match_uint16_arg(
  	uint16_t *out, struct args_info *args, const char *opt)
  {
  	const char *found = match_numeric_arg(args, opt);
  	uint16_t val;
  	char *endptr = NULL;
  
  	if (!found)
  		return 0;
  
  	val = (uint16_t)strtoul(found, &endptr, 0);
  	if (!endptr || *endptr != '\0')
  		fatal("expected number after argument", opt);
  
  	if (out)
  		*out = val;
  	return 1;
  }
  
  static int match_int_internal(
  	int *out, const char *str, int allow_negative, const char *opt)
  {
  	char *endptr = NULL;
  	int	  val = (int)strtol(str, &endptr, 10);
  
  	if (!endptr || *endptr != '\0')
  		fatal("expected number", opt);
  	else if (val < 0 && !allow_negative)
  		fatal("negative values are not allowed", opt);
  
  	if (out)
  		*out = val;
  
  	return 1;
  }
  
  int is_integer(int *out, const char *str, int allow_negative)
  {
  	return match_int_internal(out, str, allow_negative, NULL);
  }
  
  int match_int_arg(
  	int *out, struct args_info *args, const char *opt, int allow_negative)
  {
  	const char *found = match_numeric_arg(args, opt);
  	if (!found)
  		return 0;
  	return match_int_internal(out, found, allow_negative, opt);
  }
  
  int diff_output(
  	const git_diff_delta *d,
  	const git_diff_hunk *h,
  	const git_diff_line *l,
  	void *p)
  {
  	FILE *fp = p;
  
  	(void)d; (void)h;
  
  	if (!fp)
  		fp = stdout;
  
  	if (l->origin == GIT_DIFF_LINE_CONTEXT ||
  		l->origin == GIT_DIFF_LINE_ADDITION ||
  		l->origin == GIT_DIFF_LINE_DELETION)
  		fputc(l->origin, fp);
  
  	fwrite(l->content, 1, l->content_len, fp);
  
  	return 0;
  }
  
  void treeish_to_tree(
  	git_tree **out, git_repository *repo, const char *treeish)
  {
  	git_object *obj = NULL;
  
  	check_lg2(
  		git_revparse_single(&obj, repo, treeish),
  		"looking up object", treeish);
  
  	check_lg2(
  		git_object_peel((git_object **)out, obj, GIT_OBJ_TREE),
  		"resolving object to tree", treeish);
  
  	git_object_free(obj);
  }
  
  

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