Don't call Py_DECREF on null in _ttconv.cpp

jkseppan · jkseppan · commit 3dd16b505450 · 2014-04-19T15:30:43.000+03:00
Clang's static checker noted that if PyBytes_FromString returns NULL
(presumably rare) then Py_DECREF gets called on NULL; throw an
exception instead. Also assert that the char* inputs are not NULL,
since the Python API functions don't usually check that.
diff --git a/src/_ttconv.cpp b/src/_ttconv.cpp
@@ -11,6 +11,7 @@
 #include <Python.h>
 #include "ttconv/pprdrv.h"
 #include <vector>
+#include <cassert>
 
 class PythonExceptionOccurred
 {
@@ -185,14 +186,17 @@ class PythonDictionaryCallback : public TTDictionaryCallback
 
     virtual void add_pair(const char* a, const char* b)
     {
+        assert(a != NULL);
+        assert(b != NULL);
         PyObject* value = PyBytes_FromString(b);
-        if (value)
+        if (!value)
         {
-            if (PyDict_SetItemString(_dict, a, value))
-            {
-                Py_DECREF(value);
-                throw PythonExceptionOccurred();
-            }
+            throw PythonExceptionOccurred();
+        }
+        if (PyDict_SetItemString(_dict, a, value))
+        {
+            Py_DECREF(value);
+            throw PythonExceptionOccurred();
         }
         Py_DECREF(value);
     }

Original file line number	Diff line number	Diff line change
`@@ -11,6 +11,7 @@`
`11`	`11`	`#include <Python.h>`
`12`	`12`	`#include "ttconv/pprdrv.h"`
`13`	`13`	`#include <vector>`
	`14`	`+#include <cassert>`
`14`	`15`
`15`	`16`	`class PythonExceptionOccurred`
`16`	`17`	`{`
`@@ -185,14 +186,17 @@ class PythonDictionaryCallback : public TTDictionaryCallback`
`185`	`186`
`186`	`187`	`virtual void add_pair(const char* a, const char* b)`
`187`	`188`	`{`
	`189`	`+ assert(a != NULL);`
	`190`	`+ assert(b != NULL);`
`188`	`191`	`PyObject* value = PyBytes_FromString(b);`
`189`		`- if (value)`
	`192`	`+ if (!value)`
`190`	`193`	`{`
`191`		`- if (PyDict_SetItemString(_dict, a, value))`
`192`		`- {`
`193`		`- Py_DECREF(value);`
`194`		`- throw PythonExceptionOccurred();`
`195`		`- }`
	`194`	`+ throw PythonExceptionOccurred();`
	`195`	`+ }`
	`196`	`+ if (PyDict_SetItemString(_dict, a, value))`
	`197`	`+ {`
	`198`	`+ Py_DECREF(value);`
	`199`	`+ throw PythonExceptionOccurred();`
`196`	`200`	`}`
`197`	`201`	`Py_DECREF(value);`
`198`	`202`	`}`