json-caching

json.patch

diff --git a/ext/json/json.c b/ext/json/json.c
index df46294cd6..f915a492c4 100644
--- a/ext/json/json.c
+++ b/ext/json/json.c
@@ -74,6 +74,7 @@ static PHP_MINIT_FUNCTION(json)
 	PHP_JSON_REGISTER_CONSTANT("JSON_INVALID_UTF8_IGNORE", PHP_JSON_INVALID_UTF8_IGNORE);
 	PHP_JSON_REGISTER_CONSTANT("JSON_INVALID_UTF8_SUBSTITUTE", PHP_JSON_INVALID_UTF8_SUBSTITUTE);
 	PHP_JSON_REGISTER_CONSTANT("JSON_THROW_ON_ERROR", PHP_JSON_THROW_ON_ERROR);
+	PHP_JSON_REGISTER_CONSTANT("JSON_ENABLE_CACHING", PHP_JSON_ENABLE_CACHE);
 
 	/* json error constants */
 	PHP_JSON_REGISTER_CONSTANT("JSON_ERROR_NONE", PHP_JSON_ERROR_NONE);
@@ -155,6 +156,8 @@ PHP_JSON_API int php_json_encode_ex(smart_str *buf, zval *val, int options, zend
 
 	return_code = php_json_encode_zval(buf, val, options, &encoder);
 	JSON_G(error_code) = encoder.error_code;
+	
+	php_json_encode_destroy(&encoder);
 
 	return return_code;
 }
diff --git a/ext/json/json_encoder.c b/ext/json/json_encoder.c
index 92e4a10933..425133dd17 100644
--- a/ext/json/json_encoder.c
+++ b/ext/json/json_encoder.c
@@ -481,6 +481,16 @@ static int php_json_encode_serializable_object(smart_str *buf, zval *val, int op
 		return FAILURE;
 	}
 
+	if ((options & PHP_JSON_ENABLE_CACHE)) {
+		zend_string *cached = zend_hash_index_find_ptr(&encoder->cache, (zend_ulong) Z_OBJ_P(val));
+
+		if (cached) {
+			smart_str_append(buf, cached);
+
+			return SUCCESS;
+		}
+	}
+
 	PHP_JSON_HASH_PROTECT_RECURSION(myht);
 
 	ZVAL_STRING(&fname, "jsonSerialize");
@@ -510,17 +520,26 @@ static int php_json_encode_serializable_object(smart_str *buf, zval *val, int op
 		return FAILURE;
 	}
 
+	smart_str cache = {0};
+
 	if ((Z_TYPE(retval) == IS_OBJECT) &&
 		(Z_OBJ(retval) == Z_OBJ_P(val))) {
 		/* Handle the case where jsonSerialize does: return $this; by going straight to encode array */
 		PHP_JSON_HASH_UNPROTECT_RECURSION(myht);
-		return_code = php_json_encode_array(buf, &retval, options, encoder);
+		return_code = php_json_encode_array(options & PHP_JSON_ENABLE_CACHE ? &cache : buf, &retval, options, encoder);
 	} else {
 		/* All other types, encode as normal */
-		return_code = php_json_encode_zval(buf, &retval, options, encoder);
+		return_code = php_json_encode_zval(options & PHP_JSON_ENABLE_CACHE ? &cache : buf, &retval, options, encoder);
 		PHP_JSON_HASH_UNPROTECT_RECURSION(myht);
 	}
 
+	if ((return_code == SUCCESS) && (options & PHP_JSON_ENABLE_CACHE)) {
+		smart_str_append_smart_str(buf, &cache);
+
+		zend_hash_index_update_ptr(
+			&encoder->cache, (zend_ulong) Z_OBJ_P(val), cache.s);
+	}
+
 	zval_ptr_dtor(&retval);
 	zval_ptr_dtor(&fname);
 
diff --git a/ext/json/php_json.h b/ext/json/php_json.h
index ee8affa1d1..b29a56b354 100644
--- a/ext/json/php_json.h
+++ b/ext/json/php_json.h
@@ -75,6 +75,7 @@ typedef enum {
 #define PHP_JSON_INVALID_UTF8_IGNORE        (1<<20)
 #define PHP_JSON_INVALID_UTF8_SUBSTITUTE    (1<<21)
 #define PHP_JSON_THROW_ON_ERROR             (1<<22)
+#define PHP_JSON_ENABLE_CACHE               (1<<23)
 
 /* Internal flags */
 #define PHP_JSON_OUTPUT_ARRAY	0
diff --git a/ext/json/php_json_encoder.h b/ext/json/php_json_encoder.h
index 8d9825b4fb..45c5ad735e 100644
--- a/ext/json/php_json_encoder.h
+++ b/ext/json/php_json_encoder.h
@@ -25,12 +25,24 @@ typedef struct _php_json_encoder php_json_encoder;
 struct _php_json_encoder {
 	int depth;
 	int max_depth;
+	HashTable cache;
 	php_json_error_code error_code;
 };
 
+static inline void php_json_encode_cache_dtor(zval *zv) {
+	zend_string_release(Z_PTR_P(zv));
+}
+
 static inline void php_json_encode_init(php_json_encoder *encoder)
 {
 	memset(encoder, 0, sizeof(php_json_encoder));
+
+	zend_hash_init(&encoder->cache, 8, NULL, php_json_encode_cache_dtor, 0);
+}
+
+static inline void php_json_encode_destroy(php_json_encoder *encoder)
+{
+	zend_hash_destroy(&encoder->cache);
 }
 
 int php_json_encode_zval(smart_str *buf, zval *val, int options, php_json_encoder *encoder);