Mojo C++ bindings: better log messages for some validation errors at the receiver side.

mojo/public/cpp/bindings/lib/array_internal.h

 // Copyright 2013 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.
 
 #ifndef MOJO_PUBLIC_CPP_BINDINGS_LIB_ARRAY_INTERNAL_H_
 #define MOJO_PUBLIC_CPP_BINDINGS_LIB_ARRAY_INTERNAL_H_
 
 #include <new>
 #include <vector>
 
@@ skipping 198 matching lines @@
   static bool ValidateElements(const ArrayHeader* header,
                                const ElementType* elements,
                                BoundsChecker* bounds_checker) {
     MOJO_COMPILE_ASSERT(
         (IsSame<ElementValidateParams, NoValidateParams>::value),
         Handle_type_should_not_have_array_validate_params);
 
     for (uint32_t i = 0; i < header->num_elements; ++i) {
       if (!element_is_nullable &&
           elements[i].value() == kEncodedInvalidHandleValue) {
-        ReportValidationError(VALIDATION_ERROR_UNEXPECTED_INVALID_HANDLE);
+        ReportValidationError(
+            VALIDATION_ERROR_UNEXPECTED_INVALID_HANDLE,
+            MakeMessageWithArrayIndex(
+                "invalid handle in array expecting valid handles",
+                header->num_elements, i).c_str());
         return false;
       }
       if (!bounds_checker->ClaimHandle(elements[i])) {
         ReportValidationError(VALIDATION_ERROR_ILLEGAL_HANDLE);
         return false;
       }
     }
     return true;
   }
 };
@@ skipping 43 matching lines @@
     for (uint32_t i = 0; i < header->num_elements; ++i)
       Decode(&elements[i], handles);
   }
 
   template <bool element_is_nullable, typename ElementValidateParams>
   static bool ValidateElements(const ArrayHeader* header,
                                const ElementType* elements,
                                BoundsChecker* bounds_checker) {
     for (uint32_t i = 0; i < header->num_elements; ++i) {
       if (!element_is_nullable && !elements[i].offset) {
-        ReportValidationError(VALIDATION_ERROR_UNEXPECTED_NULL_POINTER);
+        ReportValidationError(
+            VALIDATION_ERROR_UNEXPECTED_NULL_POINTER,
+            MakeMessageWithArrayIndex(
+                "null in array expecting valid pointers",
+                header->num_elements, i).c_str());
         return false;
       }
       if (!ValidateEncodedPointer(&elements[i].offset)) {
         ReportValidationError(VALIDATION_ERROR_ILLEGAL_POINTER);
         return false;
       }
       if (!ValidateCaller<P, ElementValidateParams>::Run(
               DecodePointerRaw(&elements[i].offset), bounds_checker)) {
         return false;
       }
@@ skipping 55 matching lines @@
       return false;
     }
     const ArrayHeader* header = static_cast<const ArrayHeader*>(data);
     if (header->num_elements > Traits::kMaxNumElements ||
         header->num_bytes < Traits::GetStorageSize(header->num_elements)) {
       ReportValidationError(VALIDATION_ERROR_UNEXPECTED_ARRAY_HEADER);
       return false;
     }
     if (Params::expected_num_elements != 0 &&
         header->num_elements != Params::expected_num_elements) {
-      ReportValidationError(VALIDATION_ERROR_UNEXPECTED_ARRAY_HEADER);
+      ReportValidationError(
+          VALIDATION_ERROR_UNEXPECTED_ARRAY_HEADER,
+          MakeMessageWithExpectedArraySize(
+              "fixed-size array has wrong number of elements",
+              header->num_elements, Params::expected_num_elements).c_str());
       return false;
     }
     if (!bounds_checker->ClaimMemory(data, header->num_bytes)) {
       ReportValidationError(VALIDATION_ERROR_ILLEGAL_MEMORY_RANGE);
       return false;
     }
 
     const Array_Data<T>* object = static_cast<const Array_Data<T>*>(data);
     return Helper::template ValidateElements<
         Params::element_is_nullable, typename Params::ElementValidateParams>(
@@ skipping 120 matching lines @@
 };
 
 template <> struct WrapperTraits<String, false> {
   typedef String_Data* DataType;
 };
 
 }  // namespace internal
 }  // namespace mojo
 
 #endif  // MOJO_PUBLIC_CPP_BINDINGS_LIB_ARRAY_INTERNAL_H_