Outline of "ftag tag edit"

Some things are not finished yet, such as the handling of non-utf8
characters in SQL strings.

3 files changed, 123 insertions, 1 deletions

diff --git a/src/main.c b/src/main.c
index a9ab73b..912cfde 100644
--- a/src/main.c
+++ b/src/main.c
@@ -1010,11 +1010,79 @@ static void ftag_tag_add(int argc, char **argv)
 	free(new_tag_desc);
 }
 
+static int tag_edit_desc_callback(void *_old, int, char **cols, char **)
+{
+	char **old = _old;
+	assert(cols);
+	assert(cols[0]);
+	*old = strdup(cols[0]);
+	return 0;
+}
+
+static void ftag_tag_edit(int argc, char **argv)
+{
+	if (argc < 1) {
+		fprintf(stderr, "Usage: ftag tag edit [-h] [-n] NAME...\n");
+		exit(EXIT_FAILURE);
+	}
+	int opt;
+	int edit_name = 0;
+	char *column_name;
+	char *optstring = "hn";
+	char *tag_name = NULL;
+	sqlite3 *db;
+	int rc;
+	char sql[512];
+	char *old;
+	char *new;
+	optind = 1;
+	while ((opt = getopt(argc, argv, optstring)) != -1) {
+		switch (opt) {
+		case 'h':
+			printf("Usage: ftag tag edit [-h] [-n] NAME...\n");
+			exit(EXIT_SUCCESS);
+		case 'n':
+			edit_name = 1;
+			break;
+		case '?':
+		default:
+			fprintf(stderr, "Usage: ftag tag edit [-h] [-n] NAME...\n");
+			exit(EXIT_FAILURE);
+		}
+	}
+	tag_name = argv[optind];
+	/* TODO: check that tag exists */
+	db = ftag_db_open();
+	if (edit_name) {
+		column_name = "name";
+		old = strdup(tag_name);
+	}
+	else {
+		column_name = "description";
+		strbuild(sql, "SELECT description FROM tags WHERE name = '%s';",
+			 tag_name);
+		rc = sqlite3_exec(db, sql, tag_edit_desc_callback, &old, NULL);
+		sqlite3_check(rc, db);
+	}
+	new = edit(old);
+	printf("%s: old content: %s\n", __func__, old);
+	printf("%s: new content: %s\n", __func__, new);
+	sanitize_sql_str(&new);
+	/* TODO: fix isse with UTF-8 and sanitize_sql_str */
+	strbuild(sql, "UPDATE tags SET %s = '%s' WHERE name = '%s';", column_name, new, tag_name);
+	rc = sqlite3_exec(db, sql, NULL, NULL, NULL);
+	sqlite3_check(rc, db);
+	free(old);
+	free(new);
+	sqlite3_close(db);
+}
+
 static void ftag_tag_help(int, char **)
 {
 	puts("Usage: ftag tag COMMAND [ARG]...");
 	puts("Available values for COMMAND:");
 	puts("  add    create new tags");
+	puts("  edit   edit a tag");
 	puts("  help   print this help");
 	puts("  list   list available tags");
 }
@@ -1029,10 +1097,10 @@ static void ftag_tag(int argc, char **argv)
 	assert_db_exists();
 	const struct ftag_command tag_commands[] = {
 		{.name = "add",  .func = ftag_tag_add},
+		{.name = "edit",  .func = ftag_tag_edit},
 		{.name = "help", .func = ftag_tag_help},
 		{.name = "list", .func = ftag_tag_list}
 		/* TODO: add an alias command */
-		/* TODO: add an edit command */
 	};
 	int tag_command_count = sizeof(tag_commands) / sizeof(struct ftag_command);
 	parse_args(argc - 1, argv + 1, tag_commands, tag_command_count);
diff --git a/src/system.c b/src/system.c
index 2f95661..ccb7ccd 100644
--- a/src/system.c
+++ b/src/system.c
@@ -122,3 +122,49 @@ int ftag_execvp(char *const *cmd, int can_exit)
 	}
 	return status;
 }
+
+char *edit(const char *initial_content)
+{
+	char tmp_file[32];
+	int tmp_fd;
+	int rc;
+	char *env_editor;
+	char editor_cmd[512];
+	char *cmd[] = {
+		"sh",
+		"-c",
+		editor_cmd,
+		NULL
+	};
+	char *new_content;
+	strcpy(tmp_file, "/tmp/ftag-XXXXXX");
+	tmp_fd = mkstemp(tmp_file);
+	sys_check(tmp_fd != -1, "mkstemp");
+	rc = write(tmp_fd, initial_content, strlen(initial_content));
+	sys_check(rc != -1, "write");
+	env_editor = getenv("EDITOR");
+	if (env_editor)
+		strbuild(editor_cmd, "%s %s", env_editor, tmp_file);
+	else
+		strbuild(editor_cmd, "%s %s", "nano", tmp_file);
+	ftag_execvp(cmd, 1);
+	new_content = file_to_string(tmp_fd);
+	close(tmp_fd);
+	return new_content;
+}
+
+char *file_to_string(int fd)
+{
+	struct stat st;
+	char *content;
+	int rc;
+	rc = lseek(fd, 0L, SEEK_SET);
+	sys_check(rc != -1, "lseek");
+	rc = fstat(fd, &st);
+	sys_check(rc != -1, "stat");
+	content = malloc(st.st_size + 1);
+	rc = read(fd, content, st.st_size);
+	sys_check(rc != -1, "read");
+	content[st.st_size] = '\0';
+	return content;
+}
diff --git a/src/system.h b/src/system.h
index 1045153..abc7c7f 100644
--- a/src/system.h
+++ b/src/system.h
@@ -31,4 +31,12 @@ void copy_file_with_encryption(const char *in, const char *out, enum encrypt enc
  * is non-zero, exit, else return -1. Return 0 on success. */
 int ftag_execvp(char *const *cmd, int can_exit);
 
+/* Create a temporary file containing INITIAL_CONTENT and open the editor to
+ * edit it, then return the edited string. */
+char *edit(const char *initial_content);
+
+/* Get the content of the open file FD as a heap-allocated string. The offset of
+ * FD is set to zero as a side effect. */
+char *file_to_string(int fd);
+
 #endif