From a2a13280f517bc76607ee680720db4b024c85f52 Mon Sep 17 00:00:00 2001
From: Duncan MacGregor <duncan.macgregor@oracle.com>
Date: Mon, 22 Aug 2022 19:48:03 +0100
Subject: [PATCH] Add some null checks to mark functions. (#812)

---
 ext/oj/fast.c      | 28 +++++++++++++++-------------
 ext/oj/intern.c    | 15 ++++++---------
 ext/oj/saj2.c      |  2 +-
 ext/oj/usual.c     |  2 +-
 ext/oj/val_stack.c |  2 +-
 5 files changed, 24 insertions(+), 25 deletions(-)

diff --git a/ext/oj/fast.c b/ext/oj/fast.c
index 93fdcec7..10c2a23d 100644
--- a/ext/oj/fast.c
+++ b/ext/oj/fast.c
@@ -677,21 +677,23 @@ static void free_doc_cb(void *x) {
 }
 
 static void mark_leaf(Leaf leaf) {
-    switch (leaf->value_type) {
-    case COL_VAL:
-        if (NULL != leaf->elements) {
-            Leaf first = leaf->elements->next;
-            Leaf e     = first;
+    if (NULL != leaf) {
+        switch (leaf->value_type) {
+        case COL_VAL:
+            if (NULL != leaf->elements) {
+                Leaf first = leaf->elements->next;
+                Leaf e     = first;
 
-            do {
-                mark_leaf(e);
-                e = e->next;
-            } while (e != first);
-        }
-        break;
-    case RUBY_VAL: mark(leaf->value); break;
+                do {
+                    mark_leaf(e);
+                    e = e->next;
+                } while (e != first);
+            }
+            break;
+        case RUBY_VAL: mark(leaf->value); break;
 
-    default: break;
+        default: break;
+        }
     }
 }
 
diff --git a/ext/oj/intern.c b/ext/oj/intern.c
index f9831fcd..8bf8dd08 100644
--- a/ext/oj/intern.c
+++ b/ext/oj/intern.c
@@ -37,13 +37,10 @@ typedef struct _hash {
 struct _hash class_hash;
 struct _hash attr_hash;
 
-static struct _cache *str_cache = NULL;
 static VALUE          str_cache_obj;
 
-static struct _cache *sym_cache = NULL;
 static VALUE          sym_cache_obj;
 
-static struct _cache *attr_cache = NULL;
 static VALUE          attr_cache_obj;
 
 static VALUE form_str(const char *str, size_t len) {
@@ -93,15 +90,15 @@ void oj_hash_init(void) {
     rb_gc_register_address(&cache_class);
     rb_undef_alloc_func(cache_class);
 
-    str_cache     = cache_create(0, form_str, true, true);
+    struct _cache *str_cache     = cache_create(0, form_str, true, true);
     str_cache_obj = Data_Wrap_Struct(cache_class, cache_mark, cache_free, str_cache);
     rb_gc_register_address(&str_cache_obj);
 
-    sym_cache     = cache_create(0, form_sym, true, true);
+    struct _cache *sym_cache     = cache_create(0, form_sym, true, true);
     sym_cache_obj = Data_Wrap_Struct(cache_class, cache_mark, cache_free, sym_cache);
     rb_gc_register_address(&sym_cache_obj);
 
-    attr_cache     = cache_create(0, form_attr, false, true);
+    struct _cache *attr_cache = cache_create(0, form_attr, false, true);
     attr_cache_obj = Data_Wrap_Struct(cache_class, cache_mark, cache_free, attr_cache);
     rb_gc_register_address(&attr_cache_obj);
 
@@ -122,18 +119,18 @@ oj_str_intern(const char *key, size_t len) {
 #if HAVE_RB_ENC_INTERNED_STR && 0
     return rb_enc_interned_str(key, len, rb_utf8_encoding());
 #else
-    return cache_intern(str_cache, key, len);
+    return cache_intern(DATA_PTR(str_cache_obj), key, len);
 #endif
 }
 
 VALUE
 oj_sym_intern(const char *key, size_t len) {
-    return cache_intern(sym_cache, key, len);
+  return cache_intern(DATA_PTR(sym_cache_obj), key, len);
 }
 
 ID
 oj_attr_intern(const char *key, size_t len) {
-    return cache_intern(attr_cache, key, len);
+  return cache_intern(DATA_PTR(attr_cache_obj), key, len);
 }
 
 static uint64_t hash_calc(const uint8_t *key, size_t len) {
diff --git a/ext/oj/saj2.c b/ext/oj/saj2.c
index c0b8ffa1..4e4a8a8c 100644
--- a/ext/oj/saj2.c
+++ b/ext/oj/saj2.c
@@ -563,7 +563,7 @@ static void dfree(ojParser p) {
 }
 
 static void mark(ojParser p) {
-    if (NULL == p->ctx) {
+    if (NULL == p || NULL == p->ctx) {
         return;
     }
     Delegate d = (Delegate)p->ctx;
diff --git a/ext/oj/usual.c b/ext/oj/usual.c
index e5da49ff..a71c4480 100644
--- a/ext/oj/usual.c
+++ b/ext/oj/usual.c
@@ -684,7 +684,7 @@ static void dfree(ojParser p) {
 }
 
 static void mark(ojParser p) {
-    if (NULL == p->ctx) {
+    if (NULL == p || NULL == p->ctx) {
         return;
     }
     Delegate d = (Delegate)p->ctx;
diff --git a/ext/oj/val_stack.c b/ext/oj/val_stack.c
index f6582600..eeaeaf94 100644
--- a/ext/oj/val_stack.c
+++ b/ext/oj/val_stack.c
@@ -12,7 +12,7 @@ static void mark(void *ptr) {
     ValStack stack = (ValStack)ptr;
     Val      v;
 
-    if (0 == ptr) {
+    if (NULL == ptr) {
         return;
     }
 #ifdef HAVE_PTHREAD_MUTEX_INIT