Mojo: More data pipe implementation.

mojo/system/memory.cc

Index: mojo/system/memory.cc
diff --git a/mojo/system/memory.cc b/mojo/system/memory.cc
index 633b2bef4adb28f34e4c2129fe5d82835fce6e20..a10b021cedc035e3f669d9eea0d25c91a698b4c5 100644
--- a/mojo/system/memory.cc
+++ b/mojo/system/memory.cc
@@ -11,6 +11,8 @@
 namespace mojo {
 namespace system {
 
+// TODO(vtl): Can I make this use the non-templatized function without a
+// performance hit?
 template <size_t size>
 bool VerifyUserPointerForSize(const void* pointer, size_t count) {
   if (count > std::numeric_limits<size_t>::max() / size)
@@ -22,11 +24,25 @@ bool VerifyUserPointerForSize(const void* pointer, size_t count) {
   return count == 0 || !!pointer;
 }
 
+bool MOJO_SYSTEM_IMPL_EXPORT VerifyUserPointerForSize(const void* pointer,
+                                                      size_t size,
+                                                      size_t count) {
+  if (count > std::numeric_limits<size_t>::max() / size)
+    return false;
+
+  // TODO(vtl): If running in kernel mode, do a full verification. For now, just
+  // check that it's non-null if |size| is nonzero. (A faster user mode
+  // implementation is also possible if this check is skipped.)
+  return count == 0 || !!pointer;
+}
+
 // Explicitly instantiate the sizes we need. Add instantiations as needed.
 template MOJO_SYSTEM_IMPL_EXPORT bool VerifyUserPointerForSize<1>(
     const void*, size_t);
 template MOJO_SYSTEM_IMPL_EXPORT bool VerifyUserPointerForSize<4>(
     const void*, size_t);
+template MOJO_SYSTEM_IMPL_EXPORT bool VerifyUserPointerForSize<8>(
+    const void*, size_t);
 
 }  // namespace system
 }  // namespace mojo