Mojo: Report bindings validation errors via MojoNotifyBadMessage

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

Index: mojo/public/cpp/bindings/lib/validation_context.h
diff --git a/mojo/public/cpp/bindings/lib/bounds_checker.h b/mojo/public/cpp/bindings/lib/validation_context.h
similarity index 60%
rename from mojo/public/cpp/bindings/lib/bounds_checker.h
rename to mojo/public/cpp/bindings/lib/validation_context.h
index d59a68aa0347cf8996da05769d6020efec395fe6..5b02a59fdfc04c4dd308cafbd6162b3a36a036fd 100644
--- a/mojo/public/cpp/bindings/lib/bounds_checker.h
+++ b/mojo/public/cpp/bindings/lib/validation_context.h
@@ -2,30 +2,41 @@
 // 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_BOUNDS_CHECKER_H_
-#define MOJO_PUBLIC_CPP_BINDINGS_LIB_BOUNDS_CHECKER_H_
+#ifndef MOJO_PUBLIC_CPP_BINDINGS_LIB_VALIDATION_CONTEXT_H_
+#define MOJO_PUBLIC_CPP_BINDINGS_LIB_VALIDATION_CONTEXT_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include "base/macros.h"
+#include "base/strings/string_piece.h"
 #include "mojo/public/cpp/bindings/lib/bindings_internal.h"
 
 namespace mojo {
 
 class Handle;
+class Message;
 
 namespace internal {
 
-// BoundsChecker is used to validate object sizes, pointers and handle indices
-// for payload of incoming messages.
-class BoundsChecker {
+// ValidationContext is used when validating object sizes, pointers and handle
+// indices in the payload of incoming messages.
+class ValidationContext {
  public:
   // [data, data + data_num_bytes) specifies the initial valid memory range.
   // [0, num_handles) specifies the initial valid range of handle indices.
-  BoundsChecker(const void* data, uint32_t data_num_bytes, size_t num_handles);
-
-  ~BoundsChecker();
+  //
+  // If provided, |message| and |description| provide additional information
+  // to use when reporting validation errors. In addition if |message| is
+  // provided, the MojoNotifyBadMessage API will be used to notify the system of
+  // such errors.
+  ValidationContext(const void* data,
+                    uint32_t data_num_bytes,
+                    size_t num_handles,
+                    Message* message = nullptr,
+                    const base::StringPiece& description = "");
+
+  ~ValidationContext();
 
   // Claims the specified memory range.
   // The method succeeds if the range is valid to claim. (Please see
@@ -45,9 +56,15 @@ class BoundsChecker {
   // contained inside the valid memory range.
   bool IsValidRange(const void* position, uint32_t num_bytes) const;
 
+  Message* message() const { return message_; }
+  const base::StringPiece& description() const { return description_; }
+
  private:
   bool InternalIsValidRange(uintptr_t begin, uintptr_t end) const;
 
+  Message* const message_;
+  const base::StringPiece description_;
+
   // [data_begin_, data_end_) is the valid memory range.
   uintptr_t data_begin_;
   uintptr_t data_end_;
@@ -56,10 +73,10 @@ class BoundsChecker {
   uint32_t handle_begin_;
   uint32_t handle_end_;
 
-  DISALLOW_COPY_AND_ASSIGN(BoundsChecker);
+  DISALLOW_COPY_AND_ASSIGN(ValidationContext);
 };
 
 }  // namespace internal
 }  // namespace mojo
 
-#endif  // MOJO_PUBLIC_CPP_BINDINGS_LIB_BOUNDS_CHECKER_H_
+#endif  // MOJO_PUBLIC_CPP_BINDINGS_LIB_VALIDATION_CONTEXT_H_