thodg/libgit2/examples/checkout.c

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• Hash : ed387d4a
  Author :
  Date : 2019-07-24T12:01:27
  

  Fix example checkout to forbid rather than require -- Make the example program for checkout follow git syntax, where "--" indicates a file. This was likely just a strcmp return value confusion.

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• examples/checkout.c

• /*
   * libgit2 "checkout" example - shows how to perform checkouts
   *
   * Written by the libgit2 contributors
   *
   * To the extent possible under law, the author(s) have dedicated all copyright
   * and related and neighboring rights to this software to the public domain
   * worldwide. This software is distributed without any warranty.
   *
   * You should have received a copy of the CC0 Public Domain Dedication along
   * with this software. If not, see
   * <http://creativecommons.org/publicdomain/zero/1.0/>.
   */
  
  #include "common.h"
  #include <assert.h>
  
  /* Define the printf format specifer to use for size_t output */
  #if defined(_MSC_VER) || defined(__MINGW32__)
  #	define PRIuZ "Iu"
  #	define PRIxZ "Ix"
  #	define PRIdZ "Id"
  #else
  #	define PRIuZ "zu"
  #	define PRIxZ "zx"
  #	define PRIdZ "zd"
  #endif
  
  /**
   * The following example demonstrates how to do checkouts with libgit2.
   *
   * Recognized options are :
   *  --force: force the checkout to happen.
   *  --[no-]progress: show checkout progress, on by default.
   *  --perf: show performance data.
   */
  
  typedef struct {
  	int force : 1;
  	int progress : 1;
  	int perf : 1;
  } checkout_options;
  
  static void print_usage(void)
  {
  	fprintf(stderr, "usage: checkout [options] <branch>\n"
  		"Options are :\n"
  		"  --git-dir: use the following git repository.\n"
  		"  --force: force the checkout.\n"
  		"  --[no-]progress: show checkout progress.\n"
  		"  --perf: show performance data.\n");
  	exit(1);
  }
  
  static void parse_options(const char **repo_path, checkout_options *opts, struct args_info *args)
  {
  	if (args->argc <= 1)
  		print_usage();
  
  	memset(opts, 0, sizeof(*opts));
  
  	/* Default values */
  	opts->progress = 1;
  
  	for (args->pos = 1; args->pos < args->argc; ++args->pos) {
  		const char *curr = args->argv[args->pos];
  		int bool_arg;
  
  		if (strcmp(curr, "--") == 0) {
  			break;
  		} else if (!strcmp(curr, "--force")) {
  			opts->force = 1;
  		} else if (match_bool_arg(&bool_arg, args, "--progress")) {
  			opts->progress = bool_arg;
  		} else if (match_bool_arg(&bool_arg, args, "--perf")) {
  			opts->perf = bool_arg;
  		} else if (match_str_arg(repo_path, args, "--git-dir")) {
  			continue;
  		} else {
  			break;
  		}
  	}
  }
  
  /**
   * This function is called to report progression, ie. it's called once with
   * a NULL path and the number of total steps, then for each subsequent path,
   * the current completed_step value.
   */
  static void print_checkout_progress(const char *path, size_t completed_steps, size_t total_steps, void *payload)
  {
  	(void)payload;
  	if (path == NULL) {
  		printf("checkout started: %" PRIuZ " steps\n", total_steps);
  	} else {
  		printf("checkout: %s %" PRIuZ "/%" PRIuZ "\n", path, completed_steps, total_steps);
  	}
  }
  
  /**
   * This function is called when the checkout completes, and is used to report the
   * number of syscalls performed.
   */
  static void print_perf_data(const git_checkout_perfdata *perfdata, void *payload)
  {
  	(void)payload;
  	printf("perf: stat: %" PRIuZ " mkdir: %" PRIuZ " chmod: %" PRIuZ "\n",
  	       perfdata->stat_calls, perfdata->mkdir_calls, perfdata->chmod_calls);
  }
  
  /**
   * This is the main "checkout <branch>" function, responsible for performing
   * a branch-based checkout.
   */
  static int perform_checkout_ref(git_repository *repo, git_annotated_commit *target, checkout_options *opts)
  {
  	git_checkout_options checkout_opts = GIT_CHECKOUT_OPTIONS_INIT;
  	git_commit *target_commit = NULL;
  	int err;
  
  	/** Setup our checkout options from the parsed options */
  	checkout_opts.checkout_strategy = GIT_CHECKOUT_SAFE;
  	if (opts->force)
  		checkout_opts.checkout_strategy = GIT_CHECKOUT_FORCE;
  
  	if (opts->progress)
  		checkout_opts.progress_cb = print_checkout_progress;
  
  	if (opts->perf)
  		checkout_opts.perfdata_cb = print_perf_data;
  
  	/** Grab the commit we're interested to move to */
  	err = git_commit_lookup(&target_commit, repo, git_annotated_commit_id(target));
  	if (err != 0) {
  		fprintf(stderr, "failed to lookup commit: %s\n", git_error_last()->message);
  		goto cleanup;
  	}
  
  	/**
  	 * Perform the checkout so the workdir corresponds to what target_commit
  	 * contains.
  	 *
  	 * Note that it's okay to pass a git_commit here, because it will be
  	 * peeled to a tree.
  	 */
  	err = git_checkout_tree(repo, (const git_object *)target_commit, &checkout_opts);
  	if (err != 0) {
  		fprintf(stderr, "failed to checkout tree: %s\n", git_error_last()->message);
  		goto cleanup;
  	}
  
  	/**
  	 * Now that the checkout has completed, we have to update HEAD.
  	 *
  	 * Depending on the "origin" of target (ie. it's an OID or a branch name),
  	 * we might need to detach HEAD.
  	 */
  	if (git_annotated_commit_ref(target)) {
  		err = git_repository_set_head(repo, git_annotated_commit_ref(target));
  	} else {
  		err = git_repository_set_head_detached_from_annotated(repo, target);
  	}
  	if (err != 0) {
  		fprintf(stderr, "failed to update HEAD reference: %s\n", git_error_last()->message);
  		goto cleanup;
  	}
  
  cleanup:
  	git_commit_free(target_commit);
  
  	return err;
  }
  
  /** That example's entry point */
  int lg2_checkout(git_repository *repo, int argc, char **argv)
  {
  	struct args_info args = ARGS_INFO_INIT;
  	checkout_options opts;
  	git_repository_state_t state;
  	git_annotated_commit *checkout_target = NULL;
  	int err = 0;
  	const char *path = ".";
  
  	/** Parse our command line options */
  	parse_options(&path, &opts, &args);
  
  	/** Make sure we're not about to checkout while something else is going on */
  	state = git_repository_state(repo);
  	if (state != GIT_REPOSITORY_STATE_NONE) {
  		fprintf(stderr, "repository is in unexpected state %d\n", state);
  		goto cleanup;
  	}
  
  	if (args.pos >= args.argc) {
  		fprintf(stderr, "unhandled\n");
  		err = -1;
  		goto cleanup;
  	} else if (!strcmp("--", args.argv[args.pos])) {
  		/**
  		 * Try to checkout the given path
  		 */
  
  		fprintf(stderr, "unhandled path-based checkout\n");
  		err = 1;
  		goto cleanup;
  	} else {
  		/**
  		 * Try to resolve a "refish" argument to a target libgit2 can use
  		 */
  		err = resolve_refish(&checkout_target, repo, args.argv[args.pos]);
  		if (err != 0) {
  			fprintf(stderr, "failed to resolve %s: %s\n", args.argv[args.pos], git_error_last()->message);
  			goto cleanup;
  		}
  		err = perform_checkout_ref(repo, checkout_target, &opts);
  	}
  
  cleanup:
  	git_annotated_commit_free(checkout_target);
  
  	return err;
  }
  

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