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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 #include "remoting/host/setup/native_messaging_reader.h" | |
6 | |
7 #include <string> | |
8 | |
9 #include "base/bind.h" | |
10 #include "base/json/json_reader.h" | |
11 #include "base/location.h" | |
12 #include "base/sequenced_task_runner.h" | |
13 #include "base/single_thread_task_runner.h" | |
14 #include "base/stl_util.h" | |
15 #include "base/thread_task_runner_handle.h" | |
16 #include "base/threading/sequenced_worker_pool.h" | |
17 #include "base/values.h" | |
18 #include "net/base/file_stream.h" | |
19 | |
20 namespace { | |
21 | |
22 // uint32 is specified in the protocol as the type for the message header. | |
23 typedef uint32 MessageLengthType; | |
24 | |
25 const int kMessageHeaderSize = sizeof(MessageLengthType); | |
26 | |
27 // Limit the size of received messages, to avoid excessive memory-allocation in | |
28 // this process, and potential overflow issues when casting to a signed 32-bit | |
29 // int. | |
30 const MessageLengthType kMaximumMessageSize = 1024 * 1024; | |
31 | |
32 } // namespace | |
33 | |
34 namespace remoting { | |
35 | |
36 class NativeMessagingReader::Core { | |
37 public: | |
38 Core(base::PlatformFile handle, | |
39 scoped_refptr<base::SingleThreadTaskRunner> caller_task_runner, | |
40 scoped_refptr<base::SequencedTaskRunner> read_task_runner, | |
41 base::WeakPtr<NativeMessagingReader> reader_); | |
42 ~Core(); | |
43 | |
44 // Reads a message from the Native Messaging client and passes it to | |
45 // |message_callback_| on the originating thread. Called on the reader thread. | |
46 void ReadMessage(); | |
47 | |
48 private: | |
49 // Notify the reader's EOF callback when an error occurs or EOF is reached. | |
50 void NotifyEof(); | |
51 | |
52 net::FileStream read_stream_; | |
53 | |
54 base::WeakPtr<NativeMessagingReader> reader_; | |
55 | |
56 // Used to post the caller-supplied reader callbacks on the caller thread. | |
57 scoped_refptr<base::SingleThreadTaskRunner> caller_task_runner_; | |
58 | |
59 // Used to DCHECK that the reader code executes on the correct thread. | |
60 scoped_refptr<base::SequencedTaskRunner> read_task_runner_; | |
61 | |
62 DISALLOW_COPY_AND_ASSIGN(Core); | |
63 }; | |
64 | |
65 NativeMessagingReader::Core::Core( | |
66 base::PlatformFile handle, | |
67 scoped_refptr<base::SingleThreadTaskRunner> caller_task_runner, | |
68 scoped_refptr<base::SequencedTaskRunner> read_task_runner, | |
69 base::WeakPtr<NativeMessagingReader> reader) | |
70 : read_stream_(handle, base::PLATFORM_FILE_READ, NULL), | |
71 reader_(reader), | |
72 caller_task_runner_(caller_task_runner), | |
73 read_task_runner_(read_task_runner) { | |
74 } | |
75 | |
76 NativeMessagingReader::Core::~Core() {} | |
77 | |
78 void NativeMessagingReader::Core::ReadMessage() { | |
79 DCHECK(read_task_runner_->RunsTasksOnCurrentThread()); | |
80 | |
81 // Keep reading messages until the stream is closed or an error occurs. | |
82 while (true) { | |
83 MessageLengthType message_length; | |
84 int read_result = read_stream_.ReadUntilComplete( | |
85 reinterpret_cast<char*>(&message_length), kMessageHeaderSize); | |
86 if (read_result != kMessageHeaderSize) { | |
87 // 0 means EOF which is normal and should not be logged as an error. | |
88 if (read_result != 0) { | |
89 LOG(ERROR) << "Failed to read message header, read returned " | |
90 << read_result; | |
91 } | |
92 NotifyEof(); | |
93 return; | |
94 } | |
95 | |
96 if (message_length > kMaximumMessageSize) { | |
97 LOG(ERROR) << "Message size too large: " << message_length; | |
98 NotifyEof(); | |
99 return; | |
100 } | |
101 | |
102 std::string message_json(message_length, '\0'); | |
103 read_result = read_stream_.ReadUntilComplete(string_as_array(&message_json), | |
104 message_length); | |
105 if (read_result != static_cast<int>(message_length)) { | |
106 LOG(ERROR) << "Failed to read message body, read returned " | |
107 << read_result; | |
108 NotifyEof(); | |
109 return; | |
110 } | |
111 | |
112 scoped_ptr<base::Value> message(base::JSONReader::Read(message_json)); | |
113 if (!message) { | |
114 LOG(ERROR) << "Failed to parse JSON message: " << message; | |
115 NotifyEof(); | |
116 return; | |
117 } | |
118 | |
119 // Notify callback of new message. | |
120 caller_task_runner_->PostTask( | |
121 FROM_HERE, base::Bind(&NativeMessagingReader::InvokeMessageCallback, | |
122 reader_, base::Passed(&message))); | |
123 } | |
124 } | |
125 | |
126 void NativeMessagingReader::Core::NotifyEof() { | |
127 DCHECK(read_task_runner_->RunsTasksOnCurrentThread()); | |
128 caller_task_runner_->PostTask( | |
129 FROM_HERE, | |
130 base::Bind(&NativeMessagingReader::InvokeEofCallback, reader_)); | |
131 } | |
132 | |
133 NativeMessagingReader::NativeMessagingReader(base::PlatformFile handle) | |
134 : reader_thread_("Reader"), | |
135 weak_factory_(this) { | |
136 reader_thread_.Start(); | |
137 read_task_runner_ = reader_thread_.message_loop_proxy(); | |
138 core_.reset(new Core(handle, base::ThreadTaskRunnerHandle::Get(), | |
139 read_task_runner_, weak_factory_.GetWeakPtr())); | |
140 } | |
141 | |
142 NativeMessagingReader::~NativeMessagingReader() { | |
143 read_task_runner_->DeleteSoon(FROM_HERE, core_.release()); | |
144 } | |
145 | |
146 void NativeMessagingReader::Start(MessageCallback message_callback, | |
147 base::Closure eof_callback) { | |
148 message_callback_ = message_callback; | |
149 eof_callback_ = eof_callback; | |
150 | |
151 // base::Unretained is safe since |core_| is only deleted via the | |
152 // DeleteSoon task which is posted from this class's dtor. | |
153 read_task_runner_->PostTask( | |
154 FROM_HERE, base::Bind(&NativeMessagingReader::Core::ReadMessage, | |
155 base::Unretained(core_.get()))); | |
156 } | |
157 | |
158 void NativeMessagingReader::InvokeMessageCallback( | |
159 scoped_ptr<base::Value> message) { | |
160 message_callback_.Run(message.Pass()); | |
161 } | |
162 | |
163 void NativeMessagingReader::InvokeEofCallback() { | |
164 eof_callback_.Run(); | |
165 } | |
166 | |
167 } // namespace remoting | |
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