From 811965b4756731dae5c08215ca048cb7af9b8b63 Mon Sep 17 00:00:00 2001
From: David Harvey-Macaulay <alteous@outlook.com>
Date: Mon, 22 Feb 2016 21:32:20 +0000
Subject: [PATCH] Implemented json_pack() format specifiers 's?', 'o?', and
 'O?'.

---
 src/pack_unpack.c           | 68 +++++++++++++++++++++++++++----------
 test/suites/api/test_pack.c | 48 ++++++++++++++++++++++++++
 2 files changed, 99 insertions(+), 17 deletions(-)

diff --git a/src/pack_unpack.c b/src/pack_unpack.c
index 9b1ef9e..625f4d9 100644
--- a/src/pack_unpack.c
+++ b/src/pack_unpack.c
@@ -48,7 +48,6 @@ static const char * const type_names[] = {
 
 static const char unpack_value_starters[] = "{[siIbfFOon";
 
-
 static void scanner_init(scanner_t *s, json_error_t *error,
                          size_t flags, const char *fmt)
 {
@@ -291,6 +290,26 @@ error:
     return NULL;
 }
 
+static json_t *pack_string(scanner_t *s, va_list *ap) {
+    char *str;
+    size_t len;
+    int ours;
+    int nullable;
+
+    nullable = s->start[1] == '?';
+    if (nullable)
+        next_token(s);
+
+    str = read_string(s, ap, "string", &len, &ours);
+    if (!str) {
+        return nullable ? json_null() : NULL;
+    } else if (ours) {
+        return jsonp_stringn_nocheck_own(str, len);
+    } else {
+        return json_stringn_nocheck(str, len);
+    }
+}
+
 static json_t *pack(scanner_t *s, va_list *ap)
 {
     switch(token(s)) {
@@ -301,20 +320,7 @@ static json_t *pack(scanner_t *s, va_list *ap)
             return pack_array(s, ap);
 
         case 's': /* string */
-        {
-            char *str;
-            size_t len;
-            int ours;
-
-            str = read_string(s, ap, "string", &len, &ours);
-            if(!str)
-                return NULL;
-
-            if (ours)
-                return jsonp_stringn_nocheck_own(str, len);
-            else
-                return json_stringn_nocheck(str, len);
-        }
+            return pack_string(s, ap);
 
         case 'n': /* null */
             return json_null();
@@ -332,10 +338,38 @@ static json_t *pack(scanner_t *s, va_list *ap)
             return json_real(va_arg(*ap, double));
 
         case 'O': /* a json_t object; increments refcount */
-            return json_incref(va_arg(*ap, json_t *));
+        {
+            int nullable;
+            json_t *json;
+
+            nullable = s->start[1] == '?';
+            if (nullable)
+                next_token(s);
+
+            json = va_arg(*ap, json_t *);
+            if (!json && nullable) {
+                return json_null();
+            } else {
+                return json_incref(json);
+            }
+        }
 
         case 'o': /* a json_t object; doesn't increment refcount */
-            return va_arg(*ap, json_t *);
+        {
+            int nullable;
+            json_t *json;
+
+            nullable = s->start[1] == '?';
+            if (nullable)
+                next_token(s);
+
+            json = va_arg(*ap, json_t *);
+            if (!json && nullable) {
+                return json_null();
+            } else {
+                return json;
+            }
+        }
 
         default:
             set_error(s, "<format>", "Unexpected format character '%c'",
diff --git a/test/suites/api/test_pack.c b/test/suites/api/test_pack.c
index 9a8a62c..24c49a4 100644
--- a/test/suites/api/test_pack.c
+++ b/test/suites/api/test_pack.c
@@ -83,6 +83,22 @@ static void run_tests()
         fail("json_pack string refcount failed");
     json_decref(value);
 
+    /* nullable string (defined case) */
+    value = json_pack("s?", "test");
+    if(!json_is_string(value) || strcmp("test", json_string_value(value)))
+        fail("json_pack nullable string (defined case) failed");
+    if(value->refcount != (size_t)1)
+        fail("json_pack nullable string (defined case) refcount failed");
+    json_decref(value);
+
+    /* nullable string (NULL case) */
+    value = json_pack("s?", NULL);
+    if(!json_is_null(value))
+        fail("json_pack nullable string (NULL case) failed");
+    if(value->refcount != (size_t)-1)
+        fail("json_pack nullable string (NULL case) refcount failed");
+    json_decref(value);
+
     /* string and length (int) */
     value = json_pack("s#", "test asdf", 4);
     if(!json_is_string(value) || strcmp("test", json_string_value(value)))
@@ -163,6 +179,22 @@ static void run_tests()
         fail("json_pack integer refcount failed");
     json_decref(value);
 
+    /* non-incref'd nullable object (defined case) */
+    value = json_pack("o?", json_integer(1));
+    if(!json_is_integer(value) || json_integer_value(value) != 1)
+        fail("json_pack nullable object (defined case) failed");
+    if(value->refcount != (size_t)1)
+        fail("json_pack nullable object (defined case) refcount failed");
+    json_decref(value);
+
+    /* non-incref'd nullable object (NULL case) */
+    value = json_pack("o?", NULL);
+    if(!json_is_null(value))
+        fail("json_pack nullable object (NULL case) failed");
+    if(value->refcount != (size_t)-1)
+        fail("json_pack nullable object (NULL case) refcount failed");
+    json_decref(value);
+
     /* incref'd object */
     value = json_pack("O", json_integer(1));
     if(!json_is_integer(value) || json_integer_value(value) != 1)
@@ -172,6 +204,22 @@ static void run_tests()
     json_decref(value);
     json_decref(value);
 
+    /* incref'd nullable object (defined case) */
+    value = json_pack("O?", json_integer(1));
+    if(!json_is_integer(value) || json_integer_value(value) != 1)
+        fail("json_pack incref'd nullable object (defined case) failed");
+    if(value->refcount != (size_t)2)
+        fail("json_pack incref'd nullable object (defined case) refcount failed");
+    json_decref(value);
+    json_decref(value);
+
+    /* incref'd nullable object (NULL case) */
+    value = json_pack("O?", NULL);
+    if(!json_is_null(value))
+        fail("json_pack incref'd nullable object (NULL case) failed");
+    if(value->refcount != (size_t)-1)
+        fail("json_pack incref'd nullable object (NULL case) refcount failed");
+
     /* simple object */
     value = json_pack("{s:[]}", "foo");
     if(!json_is_object(value) || json_object_size(value) != 1)