add slist argument handling, extra cleanup

when a curl_easy_setopt expects an slist, we convert an indexed datatype
that is expected to be filled with strings into an slist,
registering it for cleanup in a way that should avoid memory leaks

3 files changed, 51 insertions, 3 deletions

diff --git a/jurl.c b/jurl.c
index f5d4204..365740a 100644
--- a/jurl.c
+++ b/jurl.c
@@ -7,6 +7,18 @@ int jurl_gc(void *p, size_t s) {
 	(void) s;
 	jurl_handle *jurl = (jurl_handle*)p;
 	if (jurl->handle) curl_easy_cleanup(jurl->handle);
+	while (jurl->cleanup) {
+		struct jurl_cleanup *cur = jurl->cleanup;
+		switch (cur->type) {
+		case JURL_CLEANUP_TYPE_SLIST:
+			curl_slist_free_all(cur->slist);
+			break;
+		default:
+			janet_panic("unknown type of cleanup data in jurl_gc");
+		}
+		jurl->cleanup = cur->next;
+		free(cur);
+	}
 	return 0;
 }
 
@@ -27,6 +39,14 @@ JANET_CFUN(jurl_new) {
 	return janet_wrap_abstract(jurl);
 }
 
+struct jurl_cleanup *register_cleanup(jurl_handle *jurl, enum jurl_cleanup_type type) {
+	struct jurl_cleanup *out = malloc(sizeof(struct jurl_cleanup));
+	out->next = jurl->cleanup;
+	jurl->cleanup = out;
+	out->type = type;
+	return out;
+}
+
 JANET_CFUN(jurl_reset) {
 	janet_fixarity(argc, 1);
 	jurl_handle *jurl = (jurl_handle*)janet_getabstract(argv, 0, &jurl_type);
diff --git a/jurl.h b/jurl.h
index 382b178..4182025 100644
--- a/jurl.h
+++ b/jurl.h
@@ -3,12 +3,25 @@
 #include <janet.h>
 
 // jurl globals
+enum jurl_cleanup_type {
+	JURL_CLEANUP_TYPE_SLIST,
+};
+struct jurl_cleanup {
+	struct jurl_cleanup *next;
+	enum jurl_cleanup_type type;
+	union {
+		struct curl_slist *slist; // when JURL_CLEANUP_TYPE_SLIST
+	};
+};
+
 struct jurl_handle {
 	CURL* handle;
+	struct jurl_cleanup* cleanup;
 };
 typedef struct jurl_handle jurl_handle;
 
 // jurl.c
+struct jurl_cleanup *register_cleanup(jurl_handle *jurl, enum jurl_cleanup_type type);
 JANET_CFUN(jurl_new);
 JANET_CFUN(jurl_reset);
 JANET_CFUN(jurl_dup);
diff --git a/jurl_setopt.c b/jurl_setopt.c
index a3cf8e6..f0b0cd7 100644
--- a/jurl_setopt.c
+++ b/jurl_setopt.c
@@ -312,10 +312,25 @@ JANET_CFUN(jurl_setopt) {
 			// TODO: how to clean up leak?
 			janet_panic("jurl_setopt: FILE* not implemented");
 			break;
-		case JURL_PARAMTYPE_SLIST:
-			// TODO: make sure all slits are plain strings
-			janet_panic("jurl_setopt: slist not implemented");
+		case JURL_PARAMTYPE_SLIST: {
+			// we register the cleanup ahead of time, because...
+			struct jurl_cleanup *clean = register_cleanup(jurl, JURL_CLEANUP_TYPE_SLIST);
+
+			JanetView args = janet_getindexed(argv, 2);
+			for (int32_t i = 0; i < args.len; i++) {
+				const char *s = janet_getcstring(args.items, i);
+				// we use the cleanup pointer directly, this way...
+				struct curl_slist *newlist = curl_slist_append(clean->slist, s);
+				if (!newlist) {
+					// if we ever panic in the *middle* of handling,
+					// the slist will get cleaned up during garbage collection anyway
+					janet_panic("failed to append to slist in jurl_setopt");
+				}
+				clean->slist = newlist;
+			}
+			curl_easy_setopt(jurl->handle, opt->opt, clean->slist);
 			break;
+		}
 		case JURL_PARAMTYPE_BITMASK:
 			// TODO: bitmask table
 			janet_panic("jurl_setopt: bitmasks not implemented");