From 65e2c3559b451315935f9483c5f4e59d63441e54 Mon Sep 17 00:00:00 2001
From: Felix Fietkau <nbd@openwrt.org>
Date: Sun, 3 Feb 2008 06:05:08 +0100
Subject: [PATCH] implement uci revert

---
 cli.c     |  10 ++++-
 file.c    |   6 +--
 history.c | 132 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++-----
 uci.h     |   9 +++++
 util.c    |   5 +++
 5 files changed, 149 insertions(+), 13 deletions(-)

diff --git a/cli.c b/cli.c
index c3e92e3..946a905 100644
--- a/cli.c
+++ b/cli.c
@@ -31,6 +31,7 @@ enum {
 	CMD_SET,
 	CMD_DEL,
 	CMD_RENAME,
+	CMD_REVERT,
 	/* package cmds */
 	CMD_SHOW,
 	CMD_IMPORT,
@@ -49,6 +50,7 @@ static void uci_usage(int argc, char **argv)
 		"\tget        <config>.<section>[.<option>]\n"
 		"\tset        <config>.<section>[.<option>]=<value>\n"
 		"\trename     <config>.<section>[.<option>]=<name>\n"
+		"\trevert     <config>[.<section>[.<option>]]\n"
 		"\n"
 		"Options:\n"
 		"\t-f <file>  use <file> as input instead of stdin\n"
@@ -245,6 +247,9 @@ static int uci_do_section_cmd(int cmd, int argc, char **argv)
 	case CMD_RENAME:
 		ret = uci_rename(ctx, p, section, option, value);
 		break;
+	case CMD_REVERT:
+		ret = uci_revert(ctx, &p, section, option);
+		break;
 	case CMD_SET:
 		ret = uci_set(ctx, p, section, option, value);
 		break;
@@ -254,7 +259,7 @@ static int uci_do_section_cmd(int cmd, int argc, char **argv)
 	}
 
 	/* no save necessary for get */
-	if (cmd == CMD_GET)
+	if ((cmd == CMD_GET) || (cmd == CMD_REVERT))
 		return 0;
 
 	/* save changes, but don't commit them yet */
@@ -286,6 +291,8 @@ static int uci_cmd(int argc, char **argv)
 	else if (!strcasecmp(argv[0], "ren") ||
 	         !strcasecmp(argv[0], "rename"))
 		cmd = CMD_RENAME;
+	else if (!strcasecmp(argv[0], "revert"))
+		cmd = CMD_REVERT;
 	else if (!strcasecmp(argv[0], "del"))
 		cmd = CMD_DEL;
 	else if (!strcasecmp(argv[0], "import"))
@@ -298,6 +305,7 @@ static int uci_cmd(int argc, char **argv)
 		case CMD_SET:
 		case CMD_DEL:
 		case CMD_RENAME:
+		case CMD_REVERT:
 			return uci_do_section_cmd(cmd, argc, argv);
 		case CMD_SHOW:
 		case CMD_EXPORT:
diff --git a/file.c b/file.c
index d81bbe8..169cf6e 100644
--- a/file.c
+++ b/file.c
@@ -521,8 +521,8 @@ int uci_import(struct uci_context *ctx, FILE *stream, const char *name, struct u
 	/* make sure no memory from previous parse attempts is leaked */
 	uci_file_cleanup(ctx);
 
-	pctx = (struct uci_parse_context *) uci_malloc(ctx, sizeof(struct uci_parse_context));
-	ctx->pctx = pctx;
+	uci_alloc_parse_context(ctx);
+	pctx = ctx->pctx;
 	pctx->file = stream;
 	if (*package && single) {
 		pctx->package = *package;
@@ -673,7 +673,7 @@ int uci_commit(struct uci_context *ctx, struct uci_package **package, bool overw
 			/* freed together with the uci_package */
 			path = NULL;
 
-			/* check for updated history, just in case */
+			/* check for updated history, flush */
 			uci_load_history(ctx, p, true);
 		} else {
 			/* flush history */
diff --git a/history.c b/history.c
index 5b652b9..0526361 100644
--- a/history.c
+++ b/history.c
@@ -52,6 +52,20 @@ int uci_add_history_path(struct uci_context *ctx, const char *dir)
 	return 0;
 }
 
+static inline void uci_parse_history_tuple(struct uci_context *ctx, char **buf, char **package, char **section, char **option, char **value, bool *delete, bool *rename)
+{
+	if (**buf == '-') {
+		if (delete)
+			*delete = true;
+		*buf += 1;
+	} else if (**buf == '@') {
+		if (rename)
+			*rename = true;
+		*buf += 1;
+	}
+
+	UCI_INTERNAL(uci_parse_tuple, ctx, *buf, package, section, option, value);
+}
 static void uci_parse_history_line(struct uci_context *ctx, struct uci_package *p, char *buf)
 {
 	bool delete = false;
@@ -61,15 +75,7 @@ static void uci_parse_history_line(struct uci_context *ctx, struct uci_package *
 	char *option = NULL;
 	char *value = NULL;
 
-	if (buf[0] == '-') {
-		delete = true;
-		buf++;
-	} else if (buf[0] == '@') {
-		rename = true;
-		buf++;
-	}
-
-	UCI_INTERNAL(uci_parse_tuple, ctx, buf, &package, &section, &option, &value);
+	uci_parse_history_tuple(ctx, &buf, &package, &section, &option, &value, &delete, &rename);
 	if (!package || (strcmp(package, p->e.name) != 0))
 		goto error;
 	if (!uci_validate_name(section))
@@ -171,6 +177,114 @@ static void uci_load_history(struct uci_context *ctx, struct uci_package *p, boo
 	ctx->errno = 0;
 }
 
+static void uci_filter_history(struct uci_context *ctx, const char *name, char *section, char *option)
+{
+	struct uci_parse_context *pctx;
+	struct uci_element *e, *tmp;
+	struct uci_list list;
+	char *filename = NULL;
+	char *p = NULL;
+	char *s = NULL;
+	char *o = NULL;
+	char *v = NULL;
+	FILE *f = NULL;
+
+	uci_list_init(&list);
+	uci_alloc_parse_context(ctx);
+	pctx = ctx->pctx;
+
+	if ((asprintf(&filename, "%s/%s", ctx->savedir, name) < 0) || !filename)
+		UCI_THROW(ctx, UCI_ERR_MEM);
+
+	UCI_TRAP_SAVE(ctx, done);
+	f = uci_open_stream(ctx, filename, SEEK_SET, true, false);
+	pctx->file = f;
+	while (!feof(f)) {
+		struct uci_element *e;
+		char *buf;
+
+		uci_getln(ctx, 0);
+		buf = pctx->buf;
+		if (!buf[0])
+			continue;
+
+		/* NB: need to allocate the element before the call to 
+		 * uci_parse_history_tuple, otherwise the original string 
+		 * gets modified before it is saved */
+		e = uci_alloc_generic(ctx, UCI_TYPE_HISTORY, pctx->buf, sizeof(struct uci_element));
+		uci_list_add(&list, &e->list);
+
+		uci_parse_history_tuple(ctx, &buf, &p, &s, &o, &v, NULL, NULL);
+		if (section) {
+			if (!s || (strcmp(section, s) != 0))
+				continue;
+		}
+		if (option) {
+			if (!o || (strcmp(option, o) != 0))
+				continue;
+		}
+		/* match, drop this element again */
+		uci_free_element(e);
+	}
+
+	/* rebuild the history file */
+	rewind(f);
+	ftruncate(fileno(f), 0);
+	uci_foreach_element_safe(&list, tmp, e) {
+		fprintf(f, "%s\n", e->name);
+		uci_free_element(e);
+	}
+	UCI_TRAP_RESTORE(ctx);
+
+done:
+	if (filename)
+		free(filename);
+	uci_close_stream(f);
+	uci_foreach_element_safe(&list, tmp, e) {
+		uci_free_element(e);
+	}
+	ctx->internal = true;
+	uci_cleanup(ctx);
+}
+
+int uci_revert(struct uci_context *ctx, struct uci_package **pkg, char *section, char *option)
+{
+	struct uci_package *p;
+	char *name = NULL;
+
+	UCI_HANDLE_ERR(ctx);
+	UCI_ASSERT(ctx, pkg != NULL);
+	p = *pkg;
+	UCI_ASSERT(ctx, p != NULL);
+	UCI_ASSERT(ctx, p->confdir);
+
+	/* 
+	 * - flush unwritten changes
+	 * - save the package name
+	 * - unload the package
+	 * - filter the history
+	 * - reload the package
+	 */
+	UCI_TRAP_SAVE(ctx, error);
+	UCI_INTERNAL(uci_save, ctx, p);
+	name = uci_strdup(ctx, p->e.name);
+
+	*pkg = NULL;
+	uci_free_package(&p);
+	uci_filter_history(ctx, name, section, option);
+
+	UCI_INTERNAL(uci_load, ctx, name, &p);
+	UCI_TRAP_RESTORE(ctx);
+
+	goto done;
+error:
+	if (name)
+		free(name);
+	UCI_THROW(ctx, ctx->errno);
+done:
+	return 0;
+}
+
 int uci_save(struct uci_context *ctx, struct uci_package *p)
 {
 	FILE *f = NULL;
diff --git a/uci.h b/uci.h
index 43270c4..8e73bfe 100644
--- a/uci.h
+++ b/uci.h
@@ -251,6 +251,15 @@ extern int uci_set_confdir(struct uci_context *ctx, const char *dir);
  */
 extern int uci_add_history_path(struct uci_context *ctx, const char *dir);
 
+/**
+ * uci_revert: revert all changes to a config item
+ * @ctx: uci context
+ * @p: pointer to a uci_package struct ptr (will be replaced by the revert)
+ * @section: section name (optional)
+ * @option option name (optional)
+ */
+extern int uci_revert(struct uci_context *ctx, struct uci_package **p, char *section, char *option);
+
 /* UCI data structures */
 enum uci_type {
 	UCI_TYPE_HISTORY = 0,
diff --git a/util.c b/util.c
index e76ff6b..bcf65aa 100644
--- a/util.c
+++ b/util.c
@@ -72,6 +72,11 @@ static bool uci_validate_name(const char *str)
 	return true;
 }
 
+static void uci_alloc_parse_context(struct uci_context *ctx)
+{
+	ctx->pctx = (struct uci_parse_context *) uci_malloc(ctx, sizeof(struct uci_parse_context));
+}
+
 int uci_parse_tuple(struct uci_context *ctx, char *str, char **package, char **section, char **option, char **value)
 {
 	char *last = NULL;
-- 
2.11.0