Add grpc_json_tree to handle refcounting for channel arg.

2 files changed, 78 insertions, 0 deletions

diff --git a/src/core/lib/json/json.c b/src/core/lib/json/json.c
index 5b583a1f2e..c1a99df6c3 100644
--- a/src/core/lib/json/json.c
+++ b/src/core/lib/json/json.c
@@ -34,6 +34,8 @@
 #include <string.h>
 
 #include <grpc/support/alloc.h>
+#include <grpc/support/string_util.h>
+#include <grpc/support/sync.h>
 
 #include "src/core/lib/json/json.h"
 
@@ -62,3 +64,60 @@ void grpc_json_destroy(grpc_json *json) {
 
   gpr_free(json);
 }
+
+int grpc_json_cmp(const grpc_json* json1, const grpc_json* json2) {
+  if (json1 == NULL) {
+    if (json2 != NULL) return 1;
+    return 0;  // Both NULL.
+  } else {
+    if (json2 == NULL) return -1;
+  }
+  // Compare type.
+  if (json1->type > json2->type) return 1;
+  if (json1->type < json2->type) return -1;
+  // Compare key.
+  if (json1->key == NULL) {
+    if (json2->key != NULL) return -1;
+  } else {
+    if (json2->key == NULL) return 1;
+    int retval = strcmp(json1->key, json2->key);
+    if (retval != 0) return retval;
+  }
+  // Compare value.
+  if (json1->value == NULL) {
+    if (json2->value != NULL) return -1;
+  } else {
+    if (json2->value == NULL) return 1;
+    int retval = strcmp(json1->value, json2->value);
+    if (retval != 0) return retval;
+  }
+  // Recursively compare the next pointer.
+  int retval = grpc_json_cmp(json1->next, json2->next);
+  if (retval != 0) return retval;
+  // Recursively compare the child pointer.
+  retval = grpc_json_cmp(json1->child, json2->child);
+  if (retval != 0) return retval;
+  // Both are the same.
+  return 0;
+}
+
+grpc_json_tree* grpc_json_tree_create(const char* json_string) {
+  grpc_json_tree* tree = gpr_malloc(sizeof(*tree));
+  tree->string = gpr_strdup(json_string);
+  tree->root = grpc_json_parse_string(tree->string);
+  gpr_ref_init(&tree->refs, 1);
+  return tree;
+}
+
+grpc_json_tree* grpc_json_tree_ref(grpc_json_tree* tree) {
+  gpr_ref(&tree->refs);
+  return tree;
+}
+
+void grpc_json_tree_unref(grpc_json_tree* tree) {
+  if (gpr_unref(&tree->refs)) {
+    grpc_json_destroy(tree->root);
+    gpr_free(tree->string);
+    gpr_free(tree);
+  }
+}
diff --git a/src/core/lib/json/json.h b/src/core/lib/json/json.h
index 681df4bb77..e18ace7547 100644
--- a/src/core/lib/json/json.h
+++ b/src/core/lib/json/json.h
@@ -36,6 +36,8 @@
 
 #include <stdlib.h>
 
+#include <grpc/support/sync.h>
+
 #include "src/core/lib/json/json_common.h"
 
 /* A tree-like structure to hold json values. The key and value pointers
@@ -85,4 +87,21 @@ char *grpc_json_dump_to_string(grpc_json *json, int indent);
 grpc_json *grpc_json_create(grpc_json_type type);
 void grpc_json_destroy(grpc_json *json);
 
+/* Compares two JSON trees. */
+int grpc_json_cmp(const grpc_json* json1, const grpc_json* json2);
+
+/* A wrapper that contains the string used for underlying allocation and
+   is refcounted. */
+typedef struct {
+  grpc_json* root;
+  char* string;
+  gpr_refcount refs;
+} grpc_json_tree;
+
+/* Creates a copy of \a json_string. */
+grpc_json_tree* grpc_json_tree_create(const char* json_string);
+
+grpc_json_tree* grpc_json_tree_ref(grpc_json_tree* tree);
+void grpc_json_tree_unref(grpc_json_tree* tree);
+
 #endif /* GRPC_CORE_LIB_JSON_JSON_H */