examples/tag.c - third_party/libgit2 - Git at Google

 /*
  * libgit2 "tag" example - shows how to list, create and delete tags
  *
  * 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"

 /**
  * The following example partially reimplements the `git tag` command
  * and some of its options.
  *
  * These commands should work:

  * - Tag name listing (`tag`)
  * - Filtered tag listing with messages (`tag -n3 -l "v0.1*"`)
  * - Lightweight tag creation (`tag test v0.18.0`)
  * - Tag creation (`tag -a -m "Test message" test v0.18.0`)
  * - Tag deletion (`tag -d test`)
  *
  * The command line parsing logic is simplified and doesn't handle
  * all of the use cases.
  */

 /** tag_options represents the parsed command line options */
 typedef struct {
 	const char *message;
 	const char *pattern;
 	const char *tag_name;
 	const char *target;
 	int num_lines;
 	int force;
 } tag_options;

 /** tag_state represents the current program state for dragging around */
 typedef struct {
 	git_repository *repo;
 	tag_options *opts;
 } tag_state;

 /** An action to execute based on the command line arguments */
 typedef void (*tag_action)(tag_state *state);
 typedef struct args_info args_info;

 static void check(int result, const char *message)
 {
 	if (result) fatal(message, NULL);
 }

 /** Tag listing: Print individual message lines */
 static void print_list_lines(const char *message, const tag_state *state)
 {
 	const char *msg = message;
 	int num = state->opts->num_lines - 1;

 	if (!msg) return;

 	/** first line - headline */
 	while(*msg && *msg != '\n') printf("%c", *msg++);

 	/** skip over new lines */
 	while(*msg && *msg == '\n') msg++;

 	printf("\n");

 	/** print just headline? */
 	if (num == 0) return;
 	if (*msg && msg[1]) printf("\n");

 	/** print individual commit/tag lines */
 	while (*msg && num-- >= 2) {
 		printf("    ");

 		while (*msg && *msg != '\n') printf("%c", *msg++);

 		/** handle consecutive new lines */
 		if (*msg && *msg == '\n' && msg[1] == '\n') {
 			num--;
 			printf("\n");
 		}
 		while(*msg && *msg == '\n') msg++;

 		printf("\n");
 	}
 }

 /** Tag listing: Print an actual tag object */
 static void print_tag(git_tag *tag, const tag_state *state)
 {
 	printf("%-16s", git_tag_name(tag));

 	if (state->opts->num_lines) {
 		const char *msg = git_tag_message(tag);
 		print_list_lines(msg, state);
 	} else {
 		printf("\n");
 	}
 }

 /** Tag listing: Print a commit (target of a lightweight tag) */
 static void print_commit(git_commit *commit, const char *name,
 		const tag_state *state)
 {
 	printf("%-16s", name);

 	if (state->opts->num_lines) {
 		const char *msg = git_commit_message(commit);
 		print_list_lines(msg, state);
 	} else {
 		printf("\n");
 	}
 }

 /** Tag listing: Fallback, should not happen */
 static void print_name(const char *name)
 {
 	printf("%s\n", name);
 }

 /** Tag listing: Lookup tags based on ref name and dispatch to print */
 static int each_tag(const char *name, tag_state *state)
 {
 	git_repository *repo = state->repo;
 	git_object *obj;

 	check_lg2(git_revparse_single(&obj, repo, name),
 			"Failed to lookup rev", name);

 	switch (git_object_type(obj)) {
 		case GIT_OBJ_TAG:
 			print_tag((git_tag *) obj, state);
 			break;
 		case GIT_OBJ_COMMIT:
 			print_commit((git_commit *) obj, name, state);
 			break;
 		default:
 			print_name(name);
 	}

 	git_object_free(obj);
 	return 0;
 }

 static void action_list_tags(tag_state *state)
 {
 	const char *pattern = state->opts->pattern;
 	git_strarray tag_names = {0};
 	size_t i;

 	check_lg2(git_tag_list_match(&tag_names, pattern ? pattern : "*", state->repo),
 			"Unable to get list of tags", NULL);

 	for(i = 0; i < tag_names.count; i++) {
 		each_tag(tag_names.strings[i], state);
 	}

 	git_strarray_free(&tag_names);
 }

 static void action_delete_tag(tag_state *state)
 {
 	tag_options *opts = state->opts;
 	git_object *obj;
 	git_buf abbrev_oid = {0};

 	check(!opts->tag_name, "Name required");

 	check_lg2(git_revparse_single(&obj, state->repo, opts->tag_name),
 			"Failed to lookup rev", opts->tag_name);

 	check_lg2(git_object_short_id(&abbrev_oid, obj),
 			"Unable to get abbreviated OID", opts->tag_name);

 	check_lg2(git_tag_delete(state->repo, opts->tag_name),
 			"Unable to delete tag", opts->tag_name);

 	printf("Deleted tag '%s' (was %s)\n", opts->tag_name, abbrev_oid.ptr);

 	git_buf_free(&abbrev_oid);
 	git_object_free(obj);
 }

 static void action_create_lighweight_tag(tag_state *state)
 {
 	git_repository *repo = state->repo;
 	tag_options *opts = state->opts;
 	git_oid oid;
 	git_object *target;

 	check(!opts->tag_name, "Name required");

 	if (!opts->target) opts->target = "HEAD";

 	check(!opts->target, "Target required");

 	check_lg2(git_revparse_single(&target, repo, opts->target),
 			"Unable to resolve spec", opts->target);

 	check_lg2(git_tag_create_lightweight(&oid, repo, opts->tag_name,
 				target, opts->force), "Unable to create tag", NULL);

 	git_object_free(target);
 }

 static void action_create_tag(tag_state *state)
 {
 	git_repository *repo = state->repo;
 	tag_options *opts = state->opts;
 	git_signature *tagger;
 	git_oid oid;
 	git_object *target;

 	check(!opts->tag_name, "Name required");
 	check(!opts->message, "Message required");

 	if (!opts->target) opts->target = "HEAD";

 	check_lg2(git_revparse_single(&target, repo, opts->target),
 			"Unable to resolve spec", opts->target);

 	check_lg2(git_signature_default(&tagger, repo),
 			"Unable to create signature", NULL);

 	check_lg2(git_tag_create(&oid, repo, opts->tag_name,
 				target, tagger, opts->message, opts->force), "Unable to create tag", NULL);

 	git_object_free(target);
 	git_signature_free(tagger);
 }

 static void print_usage(void)
 {
 	fprintf(stderr, "usage: see `git help tag`\n");
 	exit(1);
 }

 /** Parse command line arguments and choose action to run when done */
 static void parse_options(tag_action *action, tag_options *opts, int argc, char **argv)
 {
 	args_info args = ARGS_INFO_INIT;
 	*action = &action_list_tags;

 	for (args.pos = 1; args.pos < argc; ++args.pos) {
 		const char *curr = argv[args.pos];

 		if (curr[0] != '-') {
 			if (!opts->tag_name)
 				opts->tag_name = curr;
 			else if (!opts->target)
 				opts->target = curr;
 			else
 				print_usage();

 			if (*action != &action_create_tag)
 				*action = &action_create_lighweight_tag;
 		} else if (!strcmp(curr, "-n")) {
 			opts->num_lines = 1;
 			*action = &action_list_tags;
 		} else if (!strcmp(curr, "-a")) {
 			*action = &action_create_tag;
 		} else if (!strcmp(curr, "-f")) {
 			opts->force = 1;
 		} else if (match_int_arg(&opts->num_lines, &args, "-n", 0)) {
 			*action = &action_list_tags;
 		} else if (match_str_arg(&opts->pattern, &args, "-l")) {
 			*action = &action_list_tags;
 		} else if (match_str_arg(&opts->tag_name, &args, "-d")) {
 			*action = &action_delete_tag;
 		} else if (match_str_arg(&opts->message, &args, "-m")) {
 			*action = &action_create_tag;
 		}
 	}
 }

 /** Initialize tag_options struct */
 static void tag_options_init(tag_options *opts)
 {
 	memset(opts, 0, sizeof(*opts));

 	opts->message   = NULL;
 	opts->pattern   = NULL;
 	opts->tag_name  = NULL;
 	opts->target    = NULL;
 	opts->num_lines = 0;
 	opts->force     = 0;
 }

 int main(int argc, char **argv)
 {
 	git_repository *repo;
 	tag_options opts;
 	tag_action action;
 	tag_state state;

 	git_libgit2_init();

 	check_lg2(git_repository_open_ext(&repo, ".", 0, NULL),
 			"Could not open repository", NULL);

 	tag_options_init(&opts);
 	parse_options(&action, &opts, argc, argv);

 	state.repo = repo;
 	state.opts = &opts;
 	action(&state);

 	git_repository_free(repo);
 	git_libgit2_shutdown();

 	return 0;
 }
	/*
	* libgit2 "tag" example - shows how to list, create and delete tags
	*
	* 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"

	/**
	* The following example partially reimplements the `git tag` command
	* and some of its options.
	*
	* These commands should work:

	* - Tag name listing (`tag`)
	* - Filtered tag listing with messages (`tag -n3 -l "v0.1*"`)
	* - Lightweight tag creation (`tag test v0.18.0`)
	* - Tag creation (`tag -a -m "Test message" test v0.18.0`)
	* - Tag deletion (`tag -d test`)
	*
	* The command line parsing logic is simplified and doesn't handle
	* all of the use cases.
	*/

	/** tag_options represents the parsed command line options */
	typedef struct {
	const char *message;
	const char *pattern;
	const char *tag_name;
	const char *target;
	int num_lines;
	int force;
	} tag_options;

	/** tag_state represents the current program state for dragging around */
	typedef struct {
	git_repository *repo;
	tag_options *opts;
	} tag_state;

	/** An action to execute based on the command line arguments */
	typedef void (tag_action)(tag_state state);
	typedef struct args_info args_info;

	static void check(int result, const char *message)
	{
	if (result) fatal(message, NULL);
	}

	/** Tag listing: Print individual message lines */
	static void print_list_lines(const char message, const tag_state state)
	{
	const char *msg = message;
	int num = state->opts->num_lines - 1;

	if (!msg) return;

	/** first line - headline */
	while(msg && msg != '\n') printf("%c", *msg++);

	/** skip over new lines */
	while(msg && msg == '\n') msg++;

	printf("\n");

	/** print just headline? */
	if (num == 0) return;
	if (*msg && msg[1]) printf("\n");

	/** print individual commit/tag lines */
	while (*msg && num-- >= 2) {
	printf(" ");

	while (msg && msg != '\n') printf("%c", *msg++);

	/** handle consecutive new lines */
	if (msg && msg == '\n' && msg[1] == '\n') {
	num--;
	printf("\n");
	}
	while(msg && msg == '\n') msg++;

	printf("\n");
	}
	}

	/** Tag listing: Print an actual tag object */
	static void print_tag(git_tag tag, const tag_state state)
	{
	printf("%-16s", git_tag_name(tag));

	if (state->opts->num_lines) {
	const char *msg = git_tag_message(tag);
	print_list_lines(msg, state);
	} else {
	printf("\n");
	}
	}

	/** Tag listing: Print a commit (target of a lightweight tag) */
	static void print_commit(git_commit commit, const char name,
	const tag_state *state)
	{
	printf("%-16s", name);

	if (state->opts->num_lines) {
	const char *msg = git_commit_message(commit);
	print_list_lines(msg, state);
	} else {
	printf("\n");
	}
	}

	/** Tag listing: Fallback, should not happen */
	static void print_name(const char *name)
	{
	printf("%s\n", name);
	}

	/** Tag listing: Lookup tags based on ref name and dispatch to print */
	static int each_tag(const char name, tag_state state)
	{
	git_repository *repo = state->repo;
	git_object *obj;

	check_lg2(git_revparse_single(&obj, repo, name),
	"Failed to lookup rev", name);

	switch (git_object_type(obj)) {
	case GIT_OBJ_TAG:
	print_tag((git_tag *) obj, state);
	break;
	case GIT_OBJ_COMMIT:
	print_commit((git_commit *) obj, name, state);
	break;
	default:
	print_name(name);
	}

	git_object_free(obj);
	return 0;
	}

	static void action_list_tags(tag_state *state)
	{
	const char *pattern = state->opts->pattern;
	git_strarray tag_names = {0};
	size_t i;

	check_lg2(git_tag_list_match(&tag_names, pattern ? pattern : "*", state->repo),
	"Unable to get list of tags", NULL);

	for(i = 0; i < tag_names.count; i++) {
	each_tag(tag_names.strings[i], state);
	}

	git_strarray_free(&tag_names);
	}

	static void action_delete_tag(tag_state *state)
	{
	tag_options *opts = state->opts;
	git_object *obj;
	git_buf abbrev_oid = {0};

	check(!opts->tag_name, "Name required");

	check_lg2(git_revparse_single(&obj, state->repo, opts->tag_name),
	"Failed to lookup rev", opts->tag_name);

	check_lg2(git_object_short_id(&abbrev_oid, obj),
	"Unable to get abbreviated OID", opts->tag_name);

	check_lg2(git_tag_delete(state->repo, opts->tag_name),
	"Unable to delete tag", opts->tag_name);

	printf("Deleted tag '%s' (was %s)\n", opts->tag_name, abbrev_oid.ptr);

	git_buf_free(&abbrev_oid);
	git_object_free(obj);
	}

	static void action_create_lighweight_tag(tag_state *state)
	{
	git_repository *repo = state->repo;
	tag_options *opts = state->opts;
	git_oid oid;
	git_object *target;

	check(!opts->tag_name, "Name required");

	if (!opts->target) opts->target = "HEAD";

	check(!opts->target, "Target required");

	check_lg2(git_revparse_single(&target, repo, opts->target),
	"Unable to resolve spec", opts->target);

	check_lg2(git_tag_create_lightweight(&oid, repo, opts->tag_name,
	target, opts->force), "Unable to create tag", NULL);

	git_object_free(target);
	}

	static void action_create_tag(tag_state *state)
	{
	git_repository *repo = state->repo;
	tag_options *opts = state->opts;
	git_signature *tagger;
	git_oid oid;
	git_object *target;

	check(!opts->tag_name, "Name required");
	check(!opts->message, "Message required");

	if (!opts->target) opts->target = "HEAD";

	check_lg2(git_revparse_single(&target, repo, opts->target),
	"Unable to resolve spec", opts->target);

	check_lg2(git_signature_default(&tagger, repo),
	"Unable to create signature", NULL);

	check_lg2(git_tag_create(&oid, repo, opts->tag_name,
	target, tagger, opts->message, opts->force), "Unable to create tag", NULL);

	git_object_free(target);
	git_signature_free(tagger);
	}

	static void print_usage(void)
	{
	fprintf(stderr, "usage: see `git help tag`\n");
	exit(1);
	}

	/** Parse command line arguments and choose action to run when done */
	static void parse_options(tag_action action, tag_options opts, int argc, char **argv)
	{
	args_info args = ARGS_INFO_INIT;
	*action = &action_list_tags;

	for (args.pos = 1; args.pos < argc; ++args.pos) {
	const char *curr = argv[args.pos];

	if (curr[0] != '-') {
	if (!opts->tag_name)
	opts->tag_name = curr;
	else if (!opts->target)
	opts->target = curr;
	else
	print_usage();

	if (*action != &action_create_tag)
	*action = &action_create_lighweight_tag;
	} else if (!strcmp(curr, "-n")) {
	opts->num_lines = 1;
	*action = &action_list_tags;
	} else if (!strcmp(curr, "-a")) {
	*action = &action_create_tag;
	} else if (!strcmp(curr, "-f")) {
	opts->force = 1;
	} else if (match_int_arg(&opts->num_lines, &args, "-n", 0)) {
	*action = &action_list_tags;
	} else if (match_str_arg(&opts->pattern, &args, "-l")) {
	*action = &action_list_tags;
	} else if (match_str_arg(&opts->tag_name, &args, "-d")) {
	*action = &action_delete_tag;
	} else if (match_str_arg(&opts->message, &args, "-m")) {
	*action = &action_create_tag;
	}
	}
	}

	/** Initialize tag_options struct */
	static void tag_options_init(tag_options *opts)
	{
	memset(opts, 0, sizeof(*opts));

	opts->message = NULL;
	opts->pattern = NULL;
	opts->tag_name = NULL;
	opts->target = NULL;
	opts->num_lines = 0;
	opts->force = 0;
	}

	int main(int argc, char **argv)
	{
	git_repository *repo;
	tag_options opts;
	tag_action action;
	tag_state state;

	git_libgit2_init();

	check_lg2(git_repository_open_ext(&repo, ".", 0, NULL),
	"Could not open repository", NULL);

	tag_options_init(&opts);
	parse_options(&action, &opts, argc, argv);

	state.repo = repo;
	state.opts = &opts;
	action(&state);

	git_repository_free(repo);
	git_libgit2_shutdown();

	return 0;
	}