Fix buffer with NULL data pointer issue.

Simply prevent buffers from ever having a NULL data pointer.

src/core/buffer.c

@@ -31,12 +31,11 @@
 /* Initialize a buffer */
 JanetBuffer *janet_buffer_init(JanetBuffer *buffer, int32_t capacity) {
     uint8_t *data = NULL;
-    if (capacity > 0) {
-        janet_gcpressure(capacity);
-        data = malloc(sizeof(uint8_t) * (size_t) capacity);
-        if (NULL == data) {
-            JANET_OUT_OF_MEMORY;
-        }
+    if (capacity < 4) capacity = 4;
+    janet_gcpressure(capacity);
+    data = malloc(sizeof(uint8_t) * (size_t) capacity);
+    if (NULL == data) {
+        JANET_OUT_OF_MEMORY;
     }
     buffer->count = 0;
     buffer->capacity = capacity;

src/core/ev.c

@@ -377,12 +377,56 @@ static int janet_stream_getter(void *p, Janet key, Janet *out) {
     return 0;
 }
 
+static void janet_stream_marshal(void *p, JanetMarshalContext *ctx) {
+    JanetStream *s = p;
+    if (!(ctx->flags & JANET_MARSHAL_UNSAFE)) {
+        janet_panic("can only marshal stream with unsafe flag");
+    }
+    janet_marshal_abstract(ctx, p);
+    janet_marshal_int(ctx, (int32_t) s->flags);
+    janet_marshal_int64(ctx, (intptr_t) s->methods);
+#ifdef JANET_WINDOWS
+    /* TODO - ref counting to avoid situation where a handle is closed or GCed
+     * while in transit, and it's value gets reused. DuplicateHandle does not work
+     * for network sockets, and in general for winsock it is better to nipt duplicate
+     * unless there is a need to. */
+    janet_marshal_int64(ctx, (int64_t)(s->handle));
+#else
+    /* Marshal after dup becuse it is easier than maintaining our own ref counting. */
+    int duph = dup(s->handle);
+    if (duph < 0) janet_panicf("failed to duplicate stream handle: %V", janet_ev_lasterr());
+    janet_marshal_int(ctx, (int32_t)(duph));
+#endif
+}
+
+static void *janet_stream_unmarshal(JanetMarshalContext *ctx) {
+    if (!(ctx->flags & JANET_MARSHAL_UNSAFE)) {
+        janet_panic("can only unmarshal stream with unsafe flag");
+    }
+    JanetStream *p = janet_unmarshal_abstract(ctx, sizeof(JanetStream));
+    /* Can't share listening state and such across threads */
+    p->_mask = 0;
+    p->state = NULL;
+    p->flags = (uint32_t) janet_unmarshal_int(ctx);
+    p->methods = (void *) janet_unmarshal_int64(ctx);
+#ifdef JANET_WINDOWS
+    p->handle = (JanetHandle) janet_unmarshal_int64(ctx);
+#else
+    p->handle = (JanetHandle) janet_unmarshal_int(ctx);
+#endif
+    return p;
+}
+
+
 const JanetAbstractType janet_stream_type = {
     "core/stream",
     janet_stream_gc,
     janet_stream_mark,
     janet_stream_getter,
-    JANET_ATEND_GET
+    NULL,
+    janet_stream_marshal,
+    janet_stream_unmarshal,
+    JANET_ATEND_UNMARSHAL
 };
 
 /* Register a fiber to resume with value */

test/suite0008.janet

@@ -336,4 +336,12 @@ neldb\0\0\0\xD8\x05printG\x01\0\xDE\xDE\xDE'\x03\0marshal_tes/\x02
 (check-replacer "aba" "ZZZZZZ" "ababababababa")
 (check-replacer "aba" "" "ababababababa")
 
+# Peg bug
+(assert (deep= @[] (peg/match '(any 1) @"")) "peg empty pattern 1")
+(assert (deep= @[] (peg/match '(any 1) (buffer))) "peg empty pattern 2")
+(assert (deep= @[] (peg/match '(any 1) "")) "peg empty pattern 3")
+(assert (deep= @[] (peg/match '(any 1) (string))) "peg empty pattern 4")
+(assert (deep= @[] (peg/match '(* "test" (any 1)) @"test")) "peg empty pattern 5")
+(assert (deep= @[] (peg/match '(* "test" (any 1)) (buffer "test"))) "peg empty pattern 6")
+
 (end-suite)