1 /*
2  * Copyright (C) 2016 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 #ifndef COMMAND_PROCESSOR_H_
18 #define COMMAND_PROCESSOR_H_
19 
20 #include <memory>
21 #include <string>
22 
23 #include "android-base/macros.h"
24 #include "android-base/unique_fd.h"
25 
26 #include "wifilogd/local_utils.h"
27 #include "wifilogd/memory_reader.h"
28 #include "wifilogd/message_buffer.h"
29 #include "wifilogd/os.h"
30 
31 namespace android {
32 namespace wifilogd {
33 
34 class CommandProcessor {
35  public:
36   // Constructs a CommandProcessor with a buffer of |buffer_size_bytes|.
37   explicit CommandProcessor(size_t buffer_size_bytes);
38 
39   // Constructs a CommandProcessor with a buffer of |buffer_size_bytes|.
40   // The CommandProcessor will use |os| to call into operating system services.
41   // This method allows tests to provide a MockOs.
42   CommandProcessor(size_t buffer_size_bytes, std::unique_ptr<Os> os);
43 
44   virtual ~CommandProcessor();
45 
46   // Processes the given command, with the given file descriptor. The effect of
47   // this call depends on the contents of |input_buf|. In particular, depending
48   // on the command, |fd| may be used for reading or writing, or |fd| may be
49   // ignored. However, |fd| is guaranteed to be closed before ProcessCommand()
50   // returns, in all cases.
51   //
52   // (Ideally, we might want to take |fd| as a unique_fd. Unfortunately,
53   // GoogleMock doesn't deal well with move-only parameters.
54   // https://github.com/google/googletest/issues/395)
55   virtual bool ProcessCommand(NONNULL const void* input_buf,
56                               size_t n_bytes_read, int fd);
57 
58  private:
59   // Copies |command_buffer| into the log buffer. Returns true if the
60   // command was copied. If |command_len| exceeds protocol::kMaxMessageSize,
61   // copies the first protocol::kMaxMessageSize of |command_buffer|, and returns
62   // true.
63   bool CopyCommandToLog(NONNULL const void* command_buffer, size_t command_len);
64 
65   // Dumps all of the logged messages to |dump_fd|. Returns true unless
66   // an unrecoverable error was encountered.
67   bool Dump(::android::base::unique_fd dump_fd);
68 
69   // Returns a human-friendly string representation of the AsciiMessage
70   // contained at the head of the memory referenced by |memory_reader|.
71   // Validates that |memory_reader| has enough bytes to contain an AsciiMessage
72   // header, and the payload described by that header. Reports any errors in
73   // the returned string.
74   std::string FormatAsciiMessage(MemoryReader memory_reader);
75 
76   // The MessageBuffer is inlined, since there's not much value to mocking
77   // simple data objects. See Testing on the Toilet Episode 173.
78   //
79   // Note that the messages in |current_log_buffer_| have not been validated,
80   // expect to ensure that:
81   // a) each message starts with a TimestampHeader, and
82   // b) each message is large enough for a protocol::Command to follow the
83   //    TimestampHeader,and
84   // c) the protocol::Command::opcode for each message is a supported opcode.
85   MessageBuffer current_log_buffer_;
86   const std::unique_ptr<Os> os_;
87 
88   DISALLOW_COPY_AND_ASSIGN(CommandProcessor);
89 };
90 
91 }  // namespace wifilogd
92 }  // namespace android
93 
94 #endif  // COMMAND_PROCESSOR_H_
95