1 files changed, 295 insertions, 0 deletions
diff --git a/src/utils/common/lookup.c b/src/utils/common/lookup.c
new file mode 100644
index 0000000..e7f6084
--- /dev/null
+++ b/src/utils/common/lookup.c
@@ -0,0 +1,295 @@
+/*  Copyright (C) 2022 CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz>
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#include <string.h>
+
+#include "utils/common/lookup.h"
+#include "contrib/mempattern.h"
+#include "contrib/ucw/mempool.h"
+#include "libknot/error.h"
+
+int lookup_init(lookup_t *lookup)
+{
+	if (lookup == NULL) {
+		return KNOT_EINVAL;
+	}
+	memset(lookup, 0, sizeof(*lookup));
+
+	mm_ctx_mempool(&lookup->mm, MM_DEFAULT_BLKSIZE);
+	lookup->trie = trie_create(&lookup->mm);
+	if (lookup->trie == NULL) {
+		mp_delete(lookup->mm.ctx);
+		return KNOT_ENOMEM;
+	}
+
+	return KNOT_EOK;
+}
+
+static void reset_output(lookup_t *lookup)
+{
+	if (lookup == NULL) {
+		return;
+	}
+
+	mm_free(&lookup->mm, lookup->found.key);
+	lookup->found.key = NULL;
+	lookup->found.data = NULL;
+
+	lookup->iter.count = 0;
+
+	mm_free(&lookup->mm, lookup->iter.first_key);
+	lookup->iter.first_key = NULL;
+
+	trie_it_free(lookup->iter.it);
+	lookup->iter.it = NULL;
+}
+
+void lookup_deinit(lookup_t *lookup)
+{
+	if (lookup == NULL) {
+		return;
+	}
+
+	reset_output(lookup);
+
+	trie_free(lookup->trie);
+	mp_delete(lookup->mm.ctx);
+}
+
+int lookup_insert(lookup_t *lookup, const char *str, void *data)
+{
+	if (lookup == NULL || str == NULL) {
+		return KNOT_EINVAL;
+	}
+
+	size_t str_len = strlen(str);
+	if (str_len == 0) {
+		return KNOT_EINVAL;
+	}
+
+	trie_val_t *val = trie_get_ins(lookup->trie, (const trie_key_t *)str, str_len);
+	if (val == NULL) {
+		return KNOT_ENOMEM;
+	}
+	*val = data;
+
+	return KNOT_EOK;
+}
+
+int lookup_remove(lookup_t *lookup, const char *str)
+{
+	if (lookup == NULL || str == NULL) {
+		return KNOT_EINVAL;
+	}
+
+	size_t str_len = strlen(str);
+	if (str_len > 0) {
+		(void)trie_del(lookup->trie, (const trie_key_t *)str, str_len, NULL);
+	}
+
+	return KNOT_EOK;
+}
+
+static int set_key(lookup_t *lookup, char **dst, const char *key, size_t key_len)
+{
+	if (*dst != NULL) {
+		mm_free(&lookup->mm, *dst);
+	}
+	*dst = mm_alloc(&lookup->mm, key_len + 1);
+	if (*dst == NULL) {
+		return KNOT_ENOMEM;
+	}
+	memcpy(*dst, key, key_len);
+	(*dst)[key_len] = '\0';
+
+	return KNOT_EOK;
+}
+
+int lookup_search(lookup_t *lookup, const char *str, size_t str_len)
+{
+	if (lookup == NULL) {
+		return KNOT_EINVAL;
+	}
+
+	// Change NULL string to the empty one.
+	if (str == NULL) {
+		str = "";
+	}
+
+	reset_output(lookup);
+
+	size_t new_len = 0;
+	trie_it_t *it = trie_it_begin(lookup->trie);
+	for (; !trie_it_finished(it); trie_it_next(it)) {
+		size_t len;
+		const char *key = (const char *)trie_it_key(it, &len);
+
+		// Compare with a shorter key.
+		if (len < str_len) {
+			int ret = memcmp(str, key, len);
+			if (ret >= 0) {
+				continue;
+			} else {
+				break;
+			}
+		}
+
+		// Compare with an equal length or longer key.
+		int ret = memcmp(str, key, str_len);
+		if (ret == 0) {
+			lookup->iter.count++;
+
+			// First candidate.
+			if (lookup->iter.count == 1) {
+				ret = set_key(lookup, &lookup->found.key, key, len);
+				if (ret != KNOT_EOK) {
+					break;
+				}
+				lookup->found.data = *trie_it_val(it);
+				new_len = len;
+			// Another candidate.
+			} else if (new_len > str_len) {
+				if (new_len > len) {
+					new_len = len;
+				}
+				while (memcmp(lookup->found.key, key, new_len) != 0) {
+					new_len--;
+				}
+			}
+		// Stop if greater than the key, and also than all the following keys.
+		} else if (ret < 0) {
+			break;
+		}
+	}
+	trie_it_free(it);
+
+	switch (lookup->iter.count) {
+	case 0:
+		return KNOT_ENOENT;
+	case 1:
+		return KNOT_EOK;
+	default:
+		// Store full name of the first candidate.
+		if (set_key(lookup, &lookup->iter.first_key, lookup->found.key,
+		            strlen(lookup->found.key)) != KNOT_EOK) {
+			return KNOT_ENOMEM;
+		}
+		lookup->found.key[new_len] = '\0';
+		lookup->found.data = NULL;
+
+		return KNOT_EFEWDATA;
+	}
+}
+
+void lookup_list(lookup_t *lookup)
+{
+	if (lookup == NULL || lookup->iter.first_key == NULL) {
+		return;
+	}
+
+	if (lookup->iter.it != NULL) {
+		if (trie_it_finished(lookup->iter.it)) {
+			trie_it_free(lookup->iter.it);
+			lookup->iter.it = NULL;
+			return;
+		}
+
+		trie_it_next(lookup->iter.it);
+
+		size_t len;
+		const char *key = (const char *)trie_it_key(lookup->iter.it, &len);
+
+		int ret = set_key(lookup, &lookup->found.key, key, len);
+		if (ret == KNOT_EOK) {
+			lookup->found.data = *trie_it_val(lookup->iter.it);
+		}
+		return;
+	}
+
+	lookup->iter.it = trie_it_begin(lookup->trie);
+	while (!trie_it_finished(lookup->iter.it)) {
+		size_t len;
+		const char *key = (const char *)trie_it_key(lookup->iter.it, &len);
+
+		if (strncmp(key, lookup->iter.first_key, len) == 0) {
+			int ret = set_key(lookup, &lookup->found.key, key, len);
+			if (ret == KNOT_EOK) {
+				lookup->found.data = *trie_it_val(lookup->iter.it);
+			}
+			break;
+		}
+		trie_it_next(lookup->iter.it);
+	}
+}
+
+static void print_options(lookup_t *lookup, EditLine *el)
+{
+	// Get terminal lines.
+	unsigned lines = 0;
+	if (el_get(el, EL_GETTC, "li", &lines) != 0 || lines < 3) {
+		return;
+	}
+
+	for (size_t i = 1; i <= lookup->iter.count; i++) {
+		lookup_list(lookup);
+		printf("\n%s", lookup->found.key);
+
+		if (i > 1 && i % (lines - 1) == 0 && i < lookup->iter.count) {
+			printf("\n Display next from %zu possibilities? (y or n)",
+			       lookup->iter.count);
+			char next;
+			el_getc(el, &next);
+			if (next != 'y') {
+				break;
+			}
+		}
+	}
+
+	printf("\n");
+	fflush(stdout);
+}
+
+int lookup_complete(lookup_t *lookup, const char *str, size_t str_len,
+                    EditLine *el, bool add_space)
+{
+	if (lookup == NULL || el == NULL) {
+		return KNOT_EINVAL;
+	}
+
+	// Try to complete the command name.
+	int ret = lookup_search(lookup, str, str_len);
+	switch (ret) {
+	case KNOT_EOK:
+		el_deletestr(el, str_len);
+		el_insertstr(el, lookup->found.key);
+		if (add_space) {
+			el_insertstr(el, " ");
+		}
+		break;
+	case KNOT_EFEWDATA:
+		if (strlen(lookup->found.key) > str_len) {
+			el_deletestr(el, str_len);
+			el_insertstr(el, lookup->found.key);
+		} else {
+			print_options(lookup, el);
+		}
+		break;
+	default:
+		break;
+	}
+
+	return ret;
+}