3 files changed, 228 insertions, 0 deletions

diff --git a/Makefile b/Makefile
index 3abba03..39b15b2 100644
--- a/Makefile
+++ b/Makefile
@@ -13,6 +13,7 @@ LDADD.ncursesw = -lncursesw
 LDLIBS = ${LDADD.libtls} ${LDADD.ncursesw}
 
 OBJS += buffer.o
+OBJS += cache.o
 OBJS += chat.o
 OBJS += command.o
 OBJS += complete.o
diff --git a/cache.c b/cache.c
new file mode 100644
index 0000000..a5348d2
--- /dev/null
+++ b/cache.c
@@ -0,0 +1,211 @@
+/* Copyright (C) 2020, 2022  June McEnroe <june@causal.agency>
+ *
+ * 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/>.
+ *
+ * Additional permission under GNU GPL version 3 section 7:
+ *
+ * If you modify this Program, or any covered work, by linking or
+ * combining it with OpenSSL (or a modified version of that library),
+ * containing parts covered by the terms of the OpenSSL License and the
+ * original SSLeay license, the licensors of this Program grant you
+ * additional permission to convey the resulting work. Corresponding
+ * Source for a non-source form of such a combination shall include the
+ * source code for the parts of OpenSSL used as well as that of the
+ * covered work.
+ */
+
+#include <err.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sysexits.h>
+
+#include "chat.h"
+
+struct Node {
+	uint id;
+	char *key;
+	enum Color color;
+	struct Node *prev;
+	struct Node *next;
+};
+
+static uint gen;
+static struct Node *head;
+static struct Node *tail;
+
+static struct Node *alloc(uint id, const char *key) {
+	struct Node *node = calloc(1, sizeof(*node));
+	if (!node) err(EX_OSERR, "calloc");
+	node->id = id;
+	node->key = strdup(key);
+	node->color = Default;
+	if (!node->key) err(EX_OSERR, "strdup");
+	return node;
+}
+
+static struct Node *detach(struct Node *node) {
+	if (node->prev) node->prev->next = node->next;
+	if (node->next) node->next->prev = node->prev;
+	if (head == node) head = node->next;
+	if (tail == node) tail = node->prev;
+	node->prev = NULL;
+	node->next = NULL;
+	return node;
+}
+
+static struct Node *prepend(struct Node *node) {
+	node->prev = NULL;
+	node->next = head;
+	if (head) head->prev = node;
+	head = node;
+	tail = (tail ?: node);
+	return node;
+}
+
+static struct Node *append(struct Node *node) {
+	node->next = NULL;
+	node->prev = tail;
+	if (tail) tail->next = node;
+	tail = node;
+	head = (head ?: node);
+	return node;
+}
+
+static struct Node *find(uint id, const char *key) {
+	for (struct Node *node = head; node; node = node->next) {
+		if (node->id != id) continue;
+		if (strcmp(node->key, key)) continue;
+		return node;
+	}
+	return NULL;
+}
+
+static struct Node *insert(bool touch, uint id, const char *key) {
+	struct Node *node = find(id, key);
+	if (node && touch) {
+		return prepend(detach(node));
+	} else if (node) {
+		return node;
+	} else if (touch) {
+		return prepend(alloc(id, key));
+	} else {
+		return append(alloc(id, key));
+	}
+}
+
+void cacheInsert(bool touch, uint id, const char *key) {
+	insert(touch, id, key);
+}
+
+void cacheInsertColor(bool touch, uint id, const char *key, enum Color color) {
+	insert(touch, id, key)->color = color;
+}
+
+void cacheReplace(bool touch, const char *old, const char *new) {
+	struct Node *next = NULL;
+	for (struct Node *node = head; node; node = next) {
+		next = node->next;
+		if (strcmp(node->key, old)) continue;
+		free(node->key);
+		node->key = strdup(new);
+		if (!node->key) err(EX_OSERR, "strdup");
+		if (touch) prepend(detach(node));
+	}
+}
+
+enum Color cacheColor(uint id, const char *key) {
+	struct Node *node = find(id, key);
+	return (node ? node->color : Default);
+}
+
+const char *cachePrefix(struct Cursor *curs, uint id, const char *prefix) {
+	size_t len = strlen(prefix);
+	if (curs->gen != gen) curs->node = NULL;
+	for (
+		curs->gen = gen, curs->node = (curs->node ? curs->node->next : head);
+		curs->node;
+		curs->node = curs->node->next
+	) {
+		if (curs->node->id && curs->node->id != id) continue;
+		if (strncasecmp(curs->node->key, prefix, len)) continue;
+		return curs->node->key;
+	}
+	return NULL;
+}
+
+const char *cacheSubstr(struct Cursor *curs, uint id, const char *substr) {
+	if (curs->gen != gen) curs->node = NULL;
+	for (
+		curs->gen = gen, curs->node = (curs->node ? curs->node->next : head);
+		curs->node;
+		curs->node = curs->node->next
+	) {
+		if (curs->node->id && curs->node->id != id) continue;
+		if (!strstr(curs->node->key, substr)) continue;
+		return curs->node->key;
+	}
+	return NULL;
+}
+
+uint cacheID(struct Cursor *curs, const char *key) {
+	if (curs->gen != gen) curs->node = NULL;
+	for (
+		curs->gen = gen, curs->node = (curs->node ? curs->node->next : head);
+		curs->node;
+		curs->node = curs->node->next
+	) {
+		if (!curs->node->id) continue;
+		if (strcmp(curs->node->key, key)) continue;
+		return curs->node->id;
+	}
+	return None;
+}
+
+void cacheAccept(struct Cursor *curs) {
+	if (curs->gen == gen && curs->node) {
+		prepend(detach(curs->node));
+	}
+	curs->node = NULL;
+}
+
+void cacheReject(struct Cursor *curs) {
+	curs->node = NULL;
+}
+
+void cacheRemove(uint id, const char *key) {
+	gen++;
+	struct Node *next = NULL;
+	for (struct Node *node = head; node; node = next) {
+		next = node->next;
+		if (id && node->id != id) continue;
+		if (strcmp(node->key, key)) continue;
+		detach(node);
+		free(node->key);
+		free(node);
+		if (id) break;
+	}
+}
+
+void cacheClear(uint id) {
+	gen++;
+	struct Node *next = NULL;
+	for (struct Node *node = head; node; node = next) {
+		next = node->next;
+		if (node->id != id) continue;
+		detach(node);
+		free(node->key);
+		free(node);
+	}
+}
diff --git a/chat.h b/chat.h
index eecb7d9..b7de9ac 100644
--- a/chat.h
+++ b/chat.h
@@ -396,6 +396,22 @@ int bufferReflow(
 	struct Buffer *buffer, int cols, enum Heat thresh, size_t tail
 );
 
+struct Cursor {
+	uint gen;
+	struct Node *node;
+};
+void cacheInsert(bool touch, uint id, const char *key);
+void cacheInsertColor(bool touch, uint id, const char *key, enum Color color);
+void cacheReplace(bool touch, const char *old, const char *new);
+enum Color cacheColor(uint id, const char *key);
+const char *cachePrefix(struct Cursor *curs, uint id, const char *prefix);
+const char *cacheSubstr(struct Cursor *curs, uint id, const char *substr);
+uint cacheID(struct Cursor *curs, const char *key);
+void cacheAccept(struct Cursor *curs);
+void cacheReject(struct Cursor *curs);
+void cacheRemove(uint id, const char *key);
+void cacheClear(uint id);
+
 const char *complete(uint id, const char *prefix);
 const char *completeSubstr(uint id, const char *substr);
 void completeAccept(void);