[epiphany/gnome-3-26] sync-records: Convert NULL to empty string for serializable string properties

[Gabriel Ivașcu <gabrielivascu src gnome org>]

commit cafbe895e43850c24f3f75c5ceabac2e4aa77f16
Author: Gabriel Ivascu <gabrielivascu gnome org>
Date:   Wed Nov 1 14:22:04 2017 +0200

    sync-records: Convert NULL to empty string for serializable string properties
    
    Firefox may afford to work with NULL values since JavaScript is more
    permissive than C, but we cannot afford to crash because of a random
    misplaced NULL value. Better be safe than sorry.

 lib/sync/ephy-history-record.c   |   28 +++++++++++++++-----------
 lib/sync/ephy-open-tabs-record.c |   11 ++++++++++
 src/bookmarks/ephy-bookmark.c    |   40 ++++++++++++++++++++-----------------
 3 files changed, 49 insertions(+), 30 deletions(-)
---
diff --git a/lib/sync/ephy-history-record.c b/lib/sync/ephy-history-record.c
index ae69863..15beed6 100644
--- a/lib/sync/ephy-history-record.c
+++ b/lib/sync/ephy-history-record.c
@@ -307,16 +307,18 @@ serializable_serialize_property (JsonSerializable *serializable,
                                  const GValue     *value,
                                  GParamSpec       *pspec)
 {
+  if (G_VALUE_HOLDS_STRING (value) && g_value_get_string (value) == NULL) {
+    JsonNode *node = json_node_new (JSON_NODE_VALUE);
+    json_node_set_string (node, "");
+    return node;
+  }
+
   if (!g_strcmp0 (name, "visits")) {
-    JsonNode *node;
-    JsonArray *array;
-    GSequence *visits;
+    JsonNode *node = json_node_new (JSON_NODE_ARRAY);
+    JsonArray *array = json_array_new ();
+    GSequence *visits = g_value_get_pointer (value);
     GSequenceIter *it;
 
-    node = json_node_new (JSON_NODE_ARRAY);
-    array = json_array_new ();
-    visits = g_value_get_pointer (value);
-
     if (visits != NULL) {
       for (it = g_sequence_get_begin_iter (visits); !g_sequence_iter_is_end (it); it = g_sequence_iter_next 
(it)) {
         EphyHistoryRecordVisit *visit = g_sequence_get (it);
@@ -342,12 +344,14 @@ serializable_deserialize_property (JsonSerializable *serializable,
                                    GParamSpec       *pspec,
                                    JsonNode         *node)
 {
-  if (!g_strcmp0 (name, "visits")) {
-    JsonArray *array;
-    GSequence *visits;
+  if (G_VALUE_HOLDS_STRING (value) && JSON_NODE_HOLDS_NULL (node)) {
+    g_value_set_string (value, "");
+    return TRUE;
+  }
 
-    array = json_node_get_array (node);
-    visits = g_sequence_new ((GDestroyNotify)ephy_history_record_visit_free);
+  if (!g_strcmp0 (name, "visits")) {
+    JsonArray *array = json_node_get_array (node);
+    GSequence *visits = g_sequence_new ((GDestroyNotify)ephy_history_record_visit_free);
 
     for (guint i = 0; i < json_array_get_length (array); i++) {
       JsonObject *object = json_node_get_object (json_array_get_element (array, i));
diff --git a/lib/sync/ephy-open-tabs-record.c b/lib/sync/ephy-open-tabs-record.c
index 5620d9e..04d2687 100644
--- a/lib/sync/ephy-open-tabs-record.c
+++ b/lib/sync/ephy-open-tabs-record.c
@@ -220,6 +220,12 @@ serializable_serialize_property (JsonSerializable *serializable,
                                  const GValue     *value,
                                  GParamSpec       *pspec)
 {
+  if (G_VALUE_HOLDS_STRING (value) && g_value_get_string (value) == NULL) {
+    JsonNode *node = json_node_new (JSON_NODE_VALUE);
+    json_node_set_string (node, "");
+    return node;
+  }
+
   if (!g_strcmp0 (name, "tabs")) {
     JsonNode *node = json_node_new (JSON_NODE_ARRAY);
     JsonArray *array = json_array_new ();
@@ -242,6 +248,11 @@ serializable_deserialize_property (JsonSerializable *serializable,
                                    GParamSpec       *pspec,
                                    JsonNode         *node)
 {
+  if (G_VALUE_HOLDS_STRING (value) && JSON_NODE_HOLDS_NULL (node)) {
+    g_value_set_string (value, "");
+    return TRUE;
+  }
+
   if (!g_strcmp0 (name, "tabs")) {
     JsonArray *array;
     GList *tabs = NULL;
diff --git a/src/bookmarks/ephy-bookmark.c b/src/bookmarks/ephy-bookmark.c
index 0bb4cbb..fc5fa95 100644
--- a/src/bookmarks/ephy-bookmark.c
+++ b/src/bookmarks/ephy-bookmark.c
@@ -520,16 +520,17 @@ serializable_serialize_property (JsonSerializable *serializable,
                                  const GValue     *value,
                                  GParamSpec       *pspec)
 {
-  JsonNode *node = NULL;
+  if (G_VALUE_HOLDS_STRING (value) && g_value_get_string (value) == NULL) {
+    JsonNode *node = json_node_new (JSON_NODE_VALUE);
+    json_node_set_string (node, "");
+    return node;
+  }
 
   if (g_strcmp0 (name, "tags") == 0) {
-    GSequence *tags;
+    JsonNode *node = json_node_new (JSON_NODE_ARRAY);
+    JsonArray *array = json_array_new ();
+    GSequence *tags = g_value_get_pointer (value);
     GSequenceIter *iter;
-    JsonArray *array;
-
-    node = json_node_new (JSON_NODE_ARRAY);
-    array = json_array_new ();
-    tags = g_value_get_pointer (value);
 
     if (tags != NULL) {
       for (iter = g_sequence_get_begin_iter (tags);
@@ -540,13 +541,15 @@ serializable_serialize_property (JsonSerializable *serializable,
     }
 
     json_node_set_array (node, array);
-  } else if (!g_strcmp0 (name, "time-added")) {
-    /* This is not a Firefox bookmark property, skip it.  */
-  } else {
-    node = json_serializable_default_serialize_property (serializable, name, value, pspec);
+
+    return node;
   }
 
-  return node;
+  /* This is not a Firefox bookmark property, skip it. */
+  if (!g_strcmp0 (name, "time-added"))
+    return NULL;
+
+  return json_serializable_default_serialize_property (serializable, name, value, pspec);
 }
 
 static gboolean
@@ -556,15 +559,16 @@ serializable_deserialize_property (JsonSerializable *serializable,
                                    GParamSpec       *pspec,
                                    JsonNode         *node)
 {
+  if (G_VALUE_HOLDS_STRING (value) && JSON_NODE_HOLDS_NULL (node)) {
+    g_value_set_string (value, "");
+    return TRUE;
+  }
+
   if (g_strcmp0 (name, "tags") == 0) {
-    GSequence *tags;
-    JsonArray *array;
+    GSequence *tags = g_sequence_new (g_free);
+    JsonArray *array = json_node_get_array (node);
     const char *tag;
 
-    g_assert (JSON_NODE_HOLDS_ARRAY (node));
-    array = json_node_get_array (node);
-    tags = g_sequence_new (g_free);
-
     for (gsize i = 0; i < json_array_get_length (array); i++) {
       tag = json_node_get_string (json_array_get_element (array, i));
       g_sequence_insert_sorted (tags, g_strdup (tag),