ext/intl usmg_parse_helper possible mem leak fixes on failure path.

introducing an utility class which calls a lambda from its destructor
when going out of scope.

Author: devnexen

ext/intl/intl_convertcpp.h

@@ -28,4 +28,41 @@ int intl_stringFromChar(UnicodeString &ret, char *str, size_t str_len, UErrorCod
 
 zend_string* intl_charFromString(const UnicodeString &from, UErrorCode *status);
 
+/**
+ * Utility class to act as a cleaner when an instance
+ * uses the expression when it goes out of its scope
+ * avoiding to needs handle all errors in all code paths
+ *
+ * note that template auto deduction is supported
+ * only from C++17, still need to be explicit
+ * at instantiation's time.
+ */
+template<typename T>
+class intl_cleaner {
+    T expr;
+    bool useexpr{true};
+public:
+    intl_cleaner(T& expr_) :
+      expr(std::move(expr_)) {}
+    intl_cleaner(const intl_cleaner& o) = delete;
+    intl_cleaner& operator=(const intl_cleaner& o) = delete;
+    // for the assignment constructors with std::move semantics
+    // we invalidate the original.
+    intl_cleaner(intl_cleaner&& o) :
+      expr(std::move(o.expr)),
+      useexpr(o.useexpr) {
+        o.useexpr = false;
+    }
+    intl_cleaner& operator=(const intl_cleaner&& o) {
+        if (&o == this)
+            return *this;
+        this->~intl_cleaner();
+        new (this)intl_cleaner(std::move(o));
+        return *this;
+    }
+    ~intl_cleaner() {
+        if (useexpr)
+            expr();
+    }
+};
 #endif /* INTL_CONVERTCPP_H */

ext/intl/msgformat/msgformat_helpers.cpp

@@ -623,11 +623,13 @@ U_CFUNC void umsg_parse_helper(UMessageFormat *fmt, int *count, zval **args, UCh
     UnicodeString srcString(source, source_len);
     Formattable *fargs = ((const MessageFormat*)fmt)->parse(srcString, *count, *status);
 
-	if(U_FAILURE(*status)) {
-		return;
-	}
+    if(U_FAILURE(*status)) {
+	    return;
+    }
 
-	*args = (zval *)safe_emalloc(*count, sizeof(zval), 0);
+    *args = (zval *)safe_emalloc(*count, sizeof(zval), 0);
+    auto fargs_expr = [&]() { delete []fargs; };
+    auto fargs_cleaner = intl_cleaner<decltype(fargs_expr)>(fargs_expr);
 
     // assign formattables to varargs
     for(int32_t i = 0; i < *count; i++) {
@@ -676,5 +678,4 @@ U_CFUNC void umsg_parse_helper(UMessageFormat *fmt, int *count, zval **args, UCh
             break;
         }
     }
-	delete[] fargs;
 }