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| 1 // Copyright 2014 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_MESSAGE_H_ | |
| 6 #define MOJO_PUBLIC_CPP_BINDINGS_MESSAGE_H_ | |
| 7 | |
| 8 #include <vector> | |
| 9 | |
| 10 #include "mojo/public/cpp/bindings/lib/message_internal.h" | |
| 11 #include "mojo/public/cpp/environment/logging.h" | |
| 12 | |
| 13 namespace mojo { | |
| 14 | |
| 15 // Message is a holder for the data and handles to be sent over a MessagePipe. | |
| 16 // Message owns its data and handles, but a consumer of Message is free to | |
| 17 // mutate the data and handles. The message's data is comprised of a header | |
| 18 // followed by payload. | |
| 19 class Message { | |
| 20 public: | |
| 21 Message(); | |
| 22 ~Message(); | |
| 23 | |
| 24 // These may only be called on a newly created Message object. | |
| 25 void AllocUninitializedData(uint32_t num_bytes); | |
| 26 void AdoptData(uint32_t num_bytes, internal::MessageData* data); | |
| 27 | |
| 28 // Swaps data and handles between this Message and another. | |
| 29 void Swap(Message* other); | |
| 30 | |
| 31 uint32_t data_num_bytes() const { return data_num_bytes_; } | |
| 32 | |
| 33 // Access the raw bytes of the message. | |
| 34 const uint8_t* data() const { | |
| 35 return reinterpret_cast<const uint8_t*>(data_); | |
| 36 } | |
| 37 uint8_t* mutable_data() { return reinterpret_cast<uint8_t*>(data_); } | |
| 38 | |
| 39 // Access the header. | |
| 40 const internal::MessageHeader* header() const { return &data_->header; } | |
| 41 | |
| 42 uint32_t name() const { return data_->header.name; } | |
| 43 bool has_flag(uint32_t flag) const { return !!(data_->header.flags & flag); } | |
| 44 | |
| 45 // Access the request_id field (if present). | |
| 46 bool has_request_id() const { return data_->header.num_fields >= 3; } | |
| 47 uint64_t request_id() const { | |
| 48 MOJO_DCHECK(has_request_id()); | |
| 49 return static_cast<const internal::MessageHeaderWithRequestID*>( | |
| 50 &data_->header)->request_id; | |
| 51 } | |
| 52 void set_request_id(uint64_t request_id) { | |
| 53 MOJO_DCHECK(has_request_id()); | |
| 54 static_cast<internal::MessageHeaderWithRequestID*>(&data_->header) | |
| 55 ->request_id = request_id; | |
| 56 } | |
| 57 | |
| 58 // Access the payload. | |
| 59 const uint8_t* payload() const { | |
| 60 return reinterpret_cast<const uint8_t*>(data_) + data_->header.num_bytes; | |
| 61 } | |
| 62 uint8_t* mutable_payload() { | |
| 63 return reinterpret_cast<uint8_t*>(data_) + data_->header.num_bytes; | |
| 64 } | |
| 65 uint32_t payload_num_bytes() const { | |
| 66 MOJO_DCHECK(data_num_bytes_ >= data_->header.num_bytes); | |
| 67 return data_num_bytes_ - data_->header.num_bytes; | |
| 68 } | |
| 69 | |
| 70 // Access the handles. | |
| 71 const std::vector<Handle>* handles() const { return &handles_; } | |
| 72 std::vector<Handle>* mutable_handles() { return &handles_; } | |
| 73 | |
| 74 private: | |
| 75 uint32_t data_num_bytes_; | |
| 76 internal::MessageData* data_; // Heap-allocated using malloc. | |
| 77 std::vector<Handle> handles_; | |
| 78 | |
| 79 MOJO_DISALLOW_COPY_AND_ASSIGN(Message); | |
| 80 }; | |
| 81 | |
| 82 class MessageReceiver { | |
| 83 public: | |
| 84 virtual ~MessageReceiver() {} | |
| 85 | |
| 86 // The receiver may mutate the given message. Returns true if the message | |
| 87 // was accepted and false otherwise, indicating that the message was invalid | |
| 88 // or malformed. | |
| 89 virtual bool Accept(Message* message) MOJO_WARN_UNUSED_RESULT = 0; | |
| 90 }; | |
| 91 | |
| 92 class MessageReceiverWithResponder : public MessageReceiver { | |
| 93 public: | |
| 94 ~MessageReceiverWithResponder() override {} | |
| 95 | |
| 96 // A variant on Accept that registers a MessageReceiver (known as the | |
| 97 // responder) to handle the response message generated from the given | |
| 98 // message. The responder's Accept method may be called during | |
| 99 // AcceptWithResponder or some time after its return. | |
| 100 // | |
| 101 // NOTE: Upon returning true, AcceptWithResponder assumes ownership of | |
| 102 // |responder| and will delete it after calling |responder->Accept| or upon | |
| 103 // its own destruction. | |
| 104 // | |
| 105 virtual bool AcceptWithResponder(Message* message, MessageReceiver* responder) | |
| 106 MOJO_WARN_UNUSED_RESULT = 0; | |
| 107 }; | |
| 108 | |
| 109 // Read a single message from the pipe and dispatch to the given receiver. The | |
| 110 // receiver may be null, in which case the message is simply discarded. | |
| 111 // Returns MOJO_RESULT_SHOULD_WAIT if the caller should wait on the handle to | |
| 112 // become readable. Returns MOJO_RESULT_OK if a message was dispatched and | |
| 113 // otherwise returns an error code if something went wrong. | |
| 114 // | |
| 115 // NOTE: The message hasn't been validated and may be malformed! | |
| 116 MojoResult ReadAndDispatchMessage(MessagePipeHandle handle, | |
| 117 MessageReceiver* receiver, | |
| 118 bool* receiver_result); | |
| 119 | |
| 120 } // namespace mojo | |
| 121 | |
| 122 #endif // MOJO_PUBLIC_CPP_BINDINGS_MESSAGE_H_ | |
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