Issue #7451: Improve decoding performance of JSON objects, and reduce

the memory consumption of said decoded objects when they use the same
strings as keys.

1 files changed, 9 insertions, 1 deletions

diff --git a/Lib/json/scanner.py b/Lib/json/scanner.py
index b4f3561..23eef61 100644
--- a/Lib/json/scanner.py
+++ b/Lib/json/scanner.py
@@ -22,6 +22,8 @@ def py_make_scanner(context):
     parse_int = context.parse_int
     parse_constant = context.parse_constant
     object_hook = context.object_hook
+    object_pairs_hook = context.object_pairs_hook
+    memo = context.memo
 
     def _scan_once(string, idx):
         try:
@@ -33,7 +35,7 @@ def py_make_scanner(context):
             return parse_string(string, idx + 1, strict)
         elif nextchar == '{':
             return parse_object((string, idx + 1), strict,
-                _scan_once, object_hook, object_pairs_hook)
+                _scan_once, object_hook, object_pairs_hook, memo)
         elif nextchar == '[':
             return parse_array((string, idx + 1), _scan_once)
         elif nextchar == 'n' and string[idx:idx + 4] == 'null':
@@ -60,6 +62,12 @@ def py_make_scanner(context):
         else:
             raise StopIteration
 
+    def scan_once(string, idx):
+        try:
+            return _scan_once(string, idx)
+        finally:
+            memo.clear()
+
     return _scan_once
 
 make_scanner = c_make_scanner or py_make_scanner