[Presentation API] Mojo typemap for content::PresentationConnectionMessage

content/common/presentation/presentation_struct_traits.cc

Index: content/common/presentation/presentation_struct_traits.cc
diff --git a/content/common/presentation/presentation_struct_traits.cc b/content/common/presentation/presentation_struct_traits.cc
new file mode 100644
index 0000000000000000000000000000000000000000..d6e2bbfd92747840d85978b0b5cb4195c0b48bd3
--- /dev/null
+++ b/content/common/presentation/presentation_struct_traits.cc
@@ -0,0 +1,64 @@
+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "content/common/presentation/presentation_struct_traits.h"
+
+#include "url/mojo/url_gurl_struct_traits.h"
+
+namespace mojo {
+
+bool StructTraits<blink::mojom::PresentationSessionInfoDataView,
+                  content::PresentationSessionInfo>::
+    Read(blink::mojom::PresentationSessionInfoDataView data,
+         content::PresentationSessionInfo* out) {
+  if (!data.ReadUrl(&(out->presentation_url)) ||
+      !data.ReadId(&(out->presentation_id))) {
+    return false;
+  }
+
+  if (out->presentation_id.empty() ||
+      !base::IsStringASCII(out->presentation_id) ||

[dcheng, 2017/03/01 00:55:50]

It seems pretty unusual to do this: no other struct traits does this. Out of
curiosity, why is it important for the presentation code to do this?

[mark a. foltz, 2017/03/03 21:03:21]

To avoid invalid ids from a compromised renderer process?  This is a
Chrome-specific restriction so it could be relaxed to valid UTF-8 to be more
flexible.

+      out->presentation_id.length() >
+          content::PresentationSessionInfo::kMaxIdLength) {
+    return false;
+  }
+  return true;
+}
+
+bool StructTraits<blink::mojom::PresentationErrorDataView,
+                  content::PresentationError>::
+    Read(blink::mojom::PresentationErrorDataView data,
+         content::PresentationError* out) {
+  if (!data.ReadErrorType(&(out->error_type)) ||
+      !data.ReadMessage(&(out->message))) {
+    return false;
+  }
+
+  if (!base::IsStringUTF8(out->message) ||
+      out->message.length() > content::PresentationError::kMaxMessageLength) {
+    return false;
+  }
+
+  return true;
+}
+
+bool UnionTraits<blink::mojom::PresentationConnectionMessageDataView,
+                 content::PresentationConnectionMessage>::
+    Read(blink::mojom::PresentationConnectionMessageDataView data,
+         content::PresentationConnectionMessage* out) {
+  if (data.is_message()) {
+    if (!data.ReadMessage(&(out->message)) ||
+        out->message->length() >
+            content::kMaxPresentationConnectionMessageSize) {
+      return false;
+    }
+  } else {
+    if (!data.ReadData(&(out->data)) ||
+        out->data->size() > content::kMaxPresentationConnectionMessageSize) {
+      return false;
+    }
+  }
+  return true;
+}
+}