1 // Copyright 2013 The Chromium Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4
5 #ifndef MOJO_PUBLIC_CPP_BINDINGS_LIB_BINDINGS_SERIALIZATION_H_
6 #define MOJO_PUBLIC_CPP_BINDINGS_LIB_BINDINGS_SERIALIZATION_H_
7
8 #include <vector>
9
10 #include "mojo/public/cpp/system/core.h"
11
12 namespace mojo {
13 namespace internal {
14
15 class BoundsChecker;
16
17 // Please note that this is a different value than |mojo::kInvalidHandleValue|,
18 // which is the "decoded" invalid handle.
19 const MojoHandle kEncodedInvalidHandleValue = static_cast<MojoHandle>(-1);
20
21 size_t Align(size_t size);
22 char* AlignPointer(char* ptr);
23
24 bool IsAligned(const void* ptr);
25
26 // Pointers are encoded as relative offsets. The offsets are relative to the
27 // address of where the offset value is stored, such that the pointer may be
28 // recovered with the expression:
29 //
30 // ptr = reinterpret_cast<char*>(offset) + *offset
31 //
32 // A null pointer is encoded as an offset value of 0.
33 //
34 void EncodePointer(const void* ptr, uint64_t* offset);
35 // Note: This function doesn't validate the encoded pointer value.
36 const void* DecodePointerRaw(const uint64_t* offset);
37
38 // Note: This function doesn't validate the encoded pointer value.
39 template <typename T>
DecodePointer(const uint64_t * offset,T ** ptr)40 inline void DecodePointer(const uint64_t* offset, T** ptr) {
41 *ptr = reinterpret_cast<T*>(const_cast<void*>(DecodePointerRaw(offset)));
42 }
43
44 // Checks whether decoding the pointer will overflow and produce a pointer
45 // smaller than |offset|.
46 bool ValidateEncodedPointer(const uint64_t* offset);
47
48 // Handles are encoded as indices into a vector of handles. These functions
49 // manipulate the value of |handle|, mapping it to and from an index.
50 void EncodeHandle(Handle* handle, std::vector<Handle>* handles);
51 // Note: This function doesn't validate the encoded handle value.
52 void DecodeHandle(Handle* handle, std::vector<Handle>* handles);
53
54 // The following 2 functions are used to encode/decode all objects (structs and
55 // arrays) in a consistent manner.
56
57 template <typename T>
Encode(T * obj,std::vector<Handle> * handles)58 inline void Encode(T* obj, std::vector<Handle>* handles) {
59 if (obj->ptr)
60 obj->ptr->EncodePointersAndHandles(handles);
61 EncodePointer(obj->ptr, &obj->offset);
62 }
63
64 // Note: This function doesn't validate the encoded pointer and handle values.
65 template <typename T>
Decode(T * obj,std::vector<Handle> * handles)66 inline void Decode(T* obj, std::vector<Handle>* handles) {
67 DecodePointer(&obj->offset, &obj->ptr);
68 if (obj->ptr)
69 obj->ptr->DecodePointersAndHandles(handles);
70 }
71
72 // If returns true, this function also claims the memory range of the size
73 // specified in the struct header, starting from |data|.
74 // Note: |min_num_bytes| must be no less than sizeof(StructHeader).
75 bool ValidateStructHeader(const void* data,
76 uint32_t min_num_bytes,
77 uint32_t min_num_fields,
78 BoundsChecker* bounds_checker);
79
80 } // namespace internal
81 } // namespace mojo
82
83 #endif // MOJO_PUBLIC_CPP_BINDINGS_LIB_BINDINGS_SERIALIZATION_H_
84