Adding upstream version 124.0.1.upstream/124.0.1

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 41 insertions, 0 deletions

diff --git a/mfbt/Try.h b/mfbt/Try.h
new file mode 100644
index 0000000000..a650a33ea2
--- /dev/null
+++ b/mfbt/Try.h
@@ -0,0 +1,41 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: set ts=8 sts=2 et sw=2 tw=80:
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_Try_h
+#define mozilla_Try_h
+
+#include "mozilla/Result.h"
+
+/**
+ * MOZ_TRY(expr) is the C++ equivalent of Rust's `try!(expr);`. First, it
+ * evaluates expr, which must produce a Result value. On success, it
+ * discards the result altogether. On error, it immediately returns an error
+ * Result from the enclosing function.
+ */
+#define MOZ_TRY(expr)                                   \
+  do {                                                  \
+    auto mozTryTempResult_ = ::mozilla::ToResult(expr); \
+    if (MOZ_UNLIKELY(mozTryTempResult_.isErr())) {      \
+      return mozTryTempResult_.propagateErr();          \
+    }                                                   \
+  } while (0)
+
+/**
+ * MOZ_TRY_VAR(target, expr) is the C++ equivalent of Rust's `target =
+ * try!(expr);`. First, it evaluates expr, which must produce a Result value. On
+ * success, the result's success value is assigned to target. On error,
+ * immediately returns the error result. |target| must be an lvalue.
+ */
+#define MOZ_TRY_VAR(target, expr)                     \
+  do {                                                \
+    auto mozTryVarTempResult_ = (expr);               \
+    if (MOZ_UNLIKELY(mozTryVarTempResult_.isErr())) { \
+      return mozTryVarTempResult_.propagateErr();     \
+    }                                                 \
+    (target) = mozTryVarTempResult_.unwrap();         \
+  } while (0)
+
+#endif  // mozilla_Try_h